new version: 2020.3.6

The 'spin' animation has a strange behaviour:
it pushes a temporary rotation matrix on the transformation stack during
cull traversal, and removes it thereafter.
Thus, the rotation matrix is missing outside of cull traversal, e.g.
when the position of Compositor lights is computed.

The same issue was fixed for the 'rotate' animation by commit
e202d4e4a5
(this mentions broken 'picking' animations as a different manifestation
of the same issue).

Fix this by setting the angle of the persistent SGRotateTransform,
instead of creating a temporary rotation matrix.

CMakeLists.txt

@@ -278,7 +278,14 @@ else()
     endif()
 endif(SIMGEAR_HEADLESS)
 
-find_package(ZLIB 1.2.4 REQUIRED)
+if(${CMAKE_SYSTEM_NAME} MATCHES "OpenBSD")
+    # As of 2020-08-01, OpenBSD's system zlib is slightly old, but it's usable
+    # with a workaround in simgear/io/iostreams/gzfstream.cxx.
+    find_package(ZLIB 1.2.3 REQUIRED)
+else()
+    find_package(ZLIB 1.2.4 REQUIRED)
+endif()
+
 find_package(CURL REQUIRED)
 
 if (SYSTEM_EXPAT)

simgear-version

@@ -1 +1 @@
-2020.3.1
+2020.3.6

simgear/canvas/Canvas.cxx

@@ -691,6 +691,10 @@ namespace canvas
       {
         _sampling_dirty = true;
       }
+      else if( name == "anisotropy" )
+      {
+        _texture.setMaxAnisotropy( node->getFloatValue() );
+      }
       else if( name == "additive-blend" )
       {
         _texture.useAdditiveBlend( node->getBoolValue() );

simgear/canvas/ODGauge.cxx

@@ -202,6 +202,12 @@ namespace canvas
     updateSampling();
   }
 
+  //----------------------------------------------------------------------------
+  void ODGauge::setMaxAnisotropy(float anis)
+  {
+    texture->setMaxAnisotropy(anis);
+  }
+
   //----------------------------------------------------------------------------
   void ODGauge::setRender(bool render)
   {

simgear/canvas/ODGauge.hxx

@@ -109,6 +109,8 @@ namespace canvas
                         int coverage_samples = 0,
                         int color_samples = 0 );
 
+      void setMaxAnisotropy(float anis);
+
       /**
        * Enable/Disable updating the texture (If disabled the contents of the
        * texture remains with the outcome of the last rendering pass)

simgear/constants.h

@@ -218,6 +218,9 @@ const float SG_RADIANS_TO_DEGREES = 180.0f / SG_PI;
 #define SG_OBJECT_RANGE_ROUGH     9000.0
 #define SG_OBJECT_RANGE_DETAILED  1500.0
 
+/** Minimum expiry time of PagedLOD within the Tile.  Overridden by /sim/rendering/plod-minimum-expiry-time-secs **/
+#define SG_TILE_MIN_EXPIRY 180.0
+
 /** Radius of scenery tiles in m **/
 #define SG_TILE_RADIUS      14000.0
 

simgear/debug/CMakeLists.txt

@@ -3,8 +3,12 @@ include (SimGearComponent)
 
 set(HEADERS debug_types.h 
     logstream.hxx BufferedLogCallback.hxx OsgIoCapture.hxx
-    LogCallback.hxx LogEntry.hxx)
+    LogCallback.hxx LogEntry.hxx
+    ErrorReportingCallback.hxx)
+
 set(SOURCES logstream.cxx BufferedLogCallback.cxx
-    LogCallback.cxx LogEntry.cxx)
+    LogCallback.cxx LogEntry.cxx
+    ErrorReportingCallback.cxx
+    )
 
 simgear_component(debug debug "${SOURCES}" "${HEADERS}")

simgear/debug/ErrorReportingCallback.cxx

@@ -0,0 +1,47 @@
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Library General Public
+// License as published by the Free Software Foundation; either
+// version 2 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Library General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+//
+
+#include <simgear_config.h>
+
+#include "ErrorReportingCallback.hxx"
+
+using std::string;
+
+namespace simgear {
+
+static ErrorReportCallback static_callback;
+
+void setErrorReportCallback(ErrorReportCallback cb)
+{
+    static_callback = cb;
+}
+
+
+void reportError(const std::string& msg, const std::string& more)
+{
+    if (!static_callback)
+        return;
+
+    static_callback(msg, more, false);
+}
+
+void reportFatalError(const std::string& msg, const std::string& more)
+{
+    if (!static_callback)
+        return;
+    static_callback(msg, more, true);
+}
+
+} // namespace simgear

simgear/debug/ErrorReportingCallback.hxx

@@ -0,0 +1,31 @@
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Library General Public
+// License as published by the Free Software Foundation; either
+// version 2 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Library General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+//
+
+#pragma once
+
+#include <functional>
+#include <string>
+
+namespace simgear {
+
+void reportError(const std::string& msg, const std::string& more = {});
+
+void reportFatalError(const std::string& msg, const std::string& more = {});
+
+using ErrorReportCallback = std::function<void(const std::string& msg, const std::string& more, bool isFatal)>;
+
+void setErrorReportCallback(ErrorReportCallback cb);
+
+} // namespace simgear

simgear/emesary/Transmitter.hxx

@@ -45,14 +45,6 @@ namespace simgear
             std::atomic<int> receiveDepth;
             std::atomic<int> sentMessageCount;
 
-            void UnlockList()
-            {
-                _lock.unlock();
-            }
-            void LockList()
-            {
-                _lock.lock();
-            }
         public:
             Transmitter() : receiveDepth(0), sentMessageCount(0)
             {
@@ -69,20 +61,17 @@ namespace simgear
             // most recently registered recipients should process the messages/events first.
             virtual void Register(IReceiver& r)
             {
-                LockList();
+                std::lock_guard<std::mutex> scopeLock(_lock);
                 recipient_list.push_back(&r);
                 r.OnRegisteredAtTransmitter(this);
                 if (std::find(deleted_recipients.begin(), deleted_recipients.end(), &r) != deleted_recipients.end())
                     deleted_recipients.remove(&r);
-
-                UnlockList();
             }
 
             //  Removes an object from receving message from this transmitter
             virtual void DeRegister(IReceiver& R)
             {
-                LockList();
-                //printf("Remove %x\n", &R);
+                std::lock_guard<std::mutex> scopeLock(_lock);
                 if (recipient_list.size())
                 {
                     if (std::find(recipient_list.begin(), recipient_list.end(), &R) != recipient_list.end())
@@ -93,7 +82,6 @@ namespace simgear
                             deleted_recipients.push_back(&R);
                     }
                 }
-                UnlockList();
             }
 
             // Notify all registered recipients. Stop when receipt status of abort or finished are received.
@@ -107,69 +95,68 @@ namespace simgear
                 ReceiptStatus return_status = ReceiptStatusNotProcessed;
 
                 sentMessageCount++;
-                try
+
+                std::vector<IReceiver*> temp;
                 {
-                    LockList();
+                    std::lock_guard<std::mutex> scopeLock(_lock);
                     if (receiveDepth == 0)
                         deleted_recipients.clear();
                     receiveDepth++;
-                    std::vector<IReceiver*> temp(recipient_list.size());
+
                     int idx = 0;
                     for (RecipientList::iterator i = recipient_list.begin(); i != recipient_list.end(); i++)
                     {
-                        temp[idx++] = *i;
+                        temp.push_back(*i);
                     }
-                    UnlockList();
-                    int tempSize = temp.size();
-                    for (int index = 0; index < tempSize; index++)
+                }
+                int tempSize = temp.size();
+                for (int index = 0; index < tempSize; index++)
+                {
+                    IReceiver* R = temp[index];
                     {
-                        IReceiver* R = temp[index];
-                        LockList();
+                        std::lock_guard<std::mutex> scopeLock(_lock);
                         if (deleted_recipients.size())
                         {
                             if (std::find(deleted_recipients.begin(), deleted_recipients.end(), R) != deleted_recipients.end())
                             {
-                                UnlockList();
                                 continue;
                             }
                         }
-                        UnlockList();
-                        if (R)
-                        {
-                            ReceiptStatus rstat = R->Receive(M);
-                            switch (rstat)
-                            {
-                            case ReceiptStatusFail:
-                                return_status = ReceiptStatusFail;
-                                break;
-                            case ReceiptStatusPending:
-                                return_status = ReceiptStatusPending;
-                                break;
-                            case ReceiptStatusPendingFinished:
-                                return rstat;
-
-                            case ReceiptStatusNotProcessed:
-                                break;
-                            case ReceiptStatusOK:
-                                if (return_status == ReceiptStatusNotProcessed)
-                                    return_status = rstat;
-                                break;
-
-                            case ReceiptStatusAbort:
-                                return ReceiptStatusAbort;
-
-                            case ReceiptStatusFinished:
-                                return ReceiptStatusOK;
-                            }
-                        }
-
                     }
+                    if (R)
+                    {
+                        ReceiptStatus rstat = R->Receive(M);
+                        switch (rstat)
+                        {
+                        case ReceiptStatusFail:
+                            return_status = ReceiptStatusFail;
+                            break;
+
+                        case ReceiptStatusPending:
+                            return_status = ReceiptStatusPending;
+                            break;
+
+                        case ReceiptStatusPendingFinished:
+                            return rstat;
+
+                        case ReceiptStatusNotProcessed:
+                            break;
+
+                        case ReceiptStatusOK:
+                            if (return_status == ReceiptStatusNotProcessed)
+                                return_status = rstat;
+                            break;
+
+                        case ReceiptStatusAbort:
+                            return ReceiptStatusAbort;
+
+                        case ReceiptStatusFinished:
+                            return ReceiptStatusOK;
+                        }
+                    }
+
                 }
-                catch (...)
-                {
-                    throw;
-                    // return_status = ReceiptStatusAbort;
-                }
+
                 receiveDepth--;
                 return return_status;
             }
@@ -177,9 +164,8 @@ namespace simgear
             // number of currently registered recipients
             virtual int Count()
             {
-                LockList();
+                std::lock_guard<std::mutex> scopeLock(_lock);
                 return recipient_list.size();
-                UnlockList();
             }
 
             // number of sent messages.

simgear/environment/metar.cxx

@@ -46,6 +46,7 @@
 #include <sstream>
 
 #include <simgear/debug/logstream.hxx>
+#include <simgear/math/sg_random.h>
 #include <simgear/structure/exception.hxx>
 
 #include "metar.hxx"
@@ -646,16 +647,21 @@ bool SGMetar::scanWind()
 	double gust = NaN;
 	if (*m == 'G') {
 		m++;
-		if (!scanNumber(&m, &i, 2, 3))
+		if (!strncmp(m, "//", 2))	// speed not measurable
+			m += 2, i = -1;
+		else if (!scanNumber(&m, &i, 2, 3))
 			return false;
-		gust = i;
+
+		if (i != -1)
+			gust = i;
 	}
+
 	double factor;
 	if (!strncmp(m, "KT", 2))
 		m += 2, factor = SG_KT_TO_MPS;
-	else if (!strncmp(m, "KMH", 3))
+	else if (!strncmp(m, "KMH", 3))		// invalid Km/h
 		m += 3, factor = SG_KMH_TO_MPS;
-	else if (!strncmp(m, "KPH", 3))		// ??
+	else if (!strncmp(m, "KPH", 3))		// invalid Km/h
 		m += 3, factor = SG_KMH_TO_MPS;
 	else if (!strncmp(m, "MPS", 3))
 		m += 3, factor = 1.0;
@@ -680,18 +686,28 @@ bool SGMetar::scanVariability()
 {
 	char *m = _m;
 	int from, to;
-	if (!scanNumber(&m, &from, 3))
+
+	if (!strncmp(m, "///", 3))	// direction not measurable
+		m += 3, from = -1;
+	else if (!scanNumber(&m, &from, 3))
 		return false;
+
 	if (*m++ != 'V')
 		return false;
-	if (!scanNumber(&m, &to, 3))
+
+	if (!strncmp(m, "///", 3))	// direction not measurable
+		m += 3, to = -1;
+	else if (!scanNumber(&m, &to, 3))
 		return false;
+
 	if (!scanBoundary(&m))
 		return false;
+
 	_m = m;
 	_wind_range_from = from;
 	_wind_range_to = to;
 	_grpcount++;
+
 	return true;
 }
 
@@ -1053,9 +1069,12 @@ bool SGMetar::scanSkyCondition()
 		return false;
 	m += i;
 
-	if (!strncmp(m, "///", 3))	// vis not measurable (e.g. because of heavy snowing)
+	if (!strncmp(m, "///", 3))	{ // vis not measurable (e.g. because of heavy snowing)
 		m += 3, i = -1;
-	else if (scanBoundary(&m)) {
+		sg_srandom_time();
+		// randomize the base height to avoid the black sky issue
+		i = 50 + static_cast<int>(sg_random() * 250.0);		// range [5,000, 30,000]
+	} else if (scanBoundary(&m)) {
 		_m = m;
 		return true;				// ignore single OVC/BKN/...
 	} else if (!scanNumber(&m, &i, 3))

simgear/environment/test_metar.cxx

@@ -81,6 +81,15 @@ void test_sensor_failure_wind()
     SGMetar m1("2020/10/23 16:55 LIVD 231655Z /////KT 9999 OVC025 10/08 Q1020 RMK OVC VIS MIN 9999 BLU");
     SG_CHECK_EQUAL(m1.getWindDir(), -1);
     SG_CHECK_EQUAL_EP2(m1.getWindSpeed_kt(), -1, TEST_EPSILON);
+
+    SGMetar m2("2020/10/21 16:55 LIVD 211655Z /////KT CAVOK 07/03 Q1023 RMK SKC VIS MIN 9999 BLU");
+    SG_CHECK_EQUAL(m2.getWindDir(), -1);
+    SG_CHECK_EQUAL_EP2(m2.getWindSpeed_kt(), -1, TEST_EPSILON);
+
+    SGMetar m3("2020/11/17 16:00 CYAZ 171600Z 14040G//KT 10SM -RA OVC012 12/11 A2895 RMK NS8 VIA CYXY SLP806 DENSITY ALT 900FT");
+    SG_CHECK_EQUAL(m3.getWindDir(), 140);
+    SG_CHECK_EQUAL_EP2(m3.getWindSpeed_kt(), 40, TEST_EPSILON);
+    SG_CHECK_EQUAL_EP2(m3.getGustSpeed_kt(), SGMetarNaN, TEST_EPSILON);
 }
 
 void test_wind_unit_not_specified()

simgear/io/DNSClient.cxx

@@ -61,6 +61,10 @@ public:
 
     struct dns_ctx * ctx;
     static size_t instanceCounter;
+
+    using RequestVec = std::vector<Request_ptr>;
+
+    RequestVec _activeRequests;
 };
 
 size_t Client::ClientPrivate::instanceCounter = 0;
@@ -78,6 +82,11 @@ Request::~Request()
 {
 }
 
+void Request::cancel()
+{
+    _cancelled = true;
+}
+
 bool Request::isTimeout() const
 {
     return (time(NULL) - _start) > _timeout_secs;
@@ -114,18 +123,20 @@ static void dnscbSRV(struct dns_ctx *ctx, struct dns_rr_srv *result, void *data)
 {
     SRVRequest * r = static_cast<SRVRequest*>(data);
     if (result) {
-        r->cname = result->dnssrv_cname;
-        r->qname = result->dnssrv_qname;
-        r->ttl = result->dnssrv_ttl;
-        for (int i = 0; i < result->dnssrv_nrr; i++) {
-            SRVRequest::SRV_ptr srv(new SRVRequest::SRV);
-            r->entries.push_back(srv);
-            srv->priority = result->dnssrv_srv[i].priority;
-            srv->weight = result->dnssrv_srv[i].weight;
-            srv->port = result->dnssrv_srv[i].port;
-            srv->target = result->dnssrv_srv[i].name;
+        if (!r->isCancelled()) {
+            r->cname = result->dnssrv_cname;
+            r->qname = result->dnssrv_qname;
+            r->ttl = result->dnssrv_ttl;
+            for (int i = 0; i < result->dnssrv_nrr; i++) {
+                SRVRequest::SRV_ptr srv(new SRVRequest::SRV);
+                r->entries.push_back(srv);
+                srv->priority = result->dnssrv_srv[i].priority;
+                srv->weight = result->dnssrv_srv[i].weight;
+                srv->port = result->dnssrv_srv[i].port;
+                srv->target = result->dnssrv_srv[i].name;
+            }
+            std::sort(r->entries.begin(), r->entries.end(), sortSRV);
         }
-        std::sort( r->entries.begin(), r->entries.end(), sortSRV );
         free(result);
     }
     r->setComplete();
@@ -134,11 +145,16 @@ static void dnscbSRV(struct dns_ctx *ctx, struct dns_rr_srv *result, void *data)
 void SRVRequest::submit( Client * client )
 {
     // if service is defined, pass service and protocol
-    if (!dns_submit_srv(client->d->ctx, getDn().c_str(), _service.empty() ? NULL : _service.c_str(), _service.empty() ? NULL : _protocol.c_str(), 0, dnscbSRV, this )) {
+    auto q = dns_submit_srv(client->d->ctx, getDn().c_str(), _service.empty() ? NULL : _service.c_str(),
+                            _service.empty() ? NULL : _protocol.c_str(),
+                            0, dnscbSRV, this);
+
+    if (!q) {
         SG_LOG(SG_IO, SG_ALERT, "Can't submit dns request for " << getDn());
         return;
     }
     _start = time(NULL);
+    _query = q;
 }
 
 TXTRequest::TXTRequest( const std::string & dn ) :
@@ -151,22 +167,24 @@ static void dnscbTXT(struct dns_ctx *ctx, struct dns_rr_txt *result, void *data)
 {
     TXTRequest * r = static_cast<TXTRequest*>(data);
     if (result) {
-        r->cname = result->dnstxt_cname;
-        r->qname = result->dnstxt_qname;
-        r->ttl = result->dnstxt_ttl;
-        for (int i = 0; i < result->dnstxt_nrr; i++) {
-          //TODO: interprete the .len field of dnstxt_txt?
-          auto rawTxt = reinterpret_cast<char*>(result->dnstxt_txt[i].txt);
-          if (!rawTxt) {
-              continue;
-          }
+        if (!r->isCancelled()) {
+            r->cname = result->dnstxt_cname;
+            r->qname = result->dnstxt_qname;
+            r->ttl = result->dnstxt_ttl;
+            for (int i = 0; i < result->dnstxt_nrr; i++) {
+                //TODO: interprete the .len field of dnstxt_txt?
+                auto rawTxt = reinterpret_cast<char*>(result->dnstxt_txt[i].txt);
+                if (!rawTxt) {
+                    continue;
+                }
 
-          const string txt{rawTxt};
-          r->entries.push_back(txt);
-          string_list tokens = simgear::strutils::split( txt, "=", 1 );
-          if( tokens.size() == 2 ) {
-            r->attributes[tokens[0]] = tokens[1];
-          }
+                const string txt{rawTxt};
+                r->entries.push_back(txt);
+                string_list tokens = simgear::strutils::split(txt, "=", 1);
+                if (tokens.size() == 2) {
+                    r->attributes[tokens[0]] = tokens[1];
+                }
+            }
         }
         free(result);
     }
@@ -176,11 +194,13 @@ static void dnscbTXT(struct dns_ctx *ctx, struct dns_rr_txt *result, void *data)
 void TXTRequest::submit( Client * client )
 {
     // protocol and service an already encoded in DN so pass in NULL for both
-    if (!dns_submit_txt(client->d->ctx, getDn().c_str(), DNS_C_IN, 0, dnscbTXT, this )) {
+    auto q = dns_submit_txt(client->d->ctx, getDn().c_str(), DNS_C_IN, 0, dnscbTXT, this);
+    if (!q) {
         SG_LOG(SG_IO, SG_ALERT, "Can't submit dns request for " << getDn());
         return;
     }
     _start = time(NULL);
+    _query = q;
 }
 
 
@@ -195,27 +215,29 @@ static void dnscbNAPTR(struct dns_ctx *ctx, struct dns_rr_naptr *result, void *d
 {
     NAPTRRequest * r = static_cast<NAPTRRequest*>(data);
     if (result) {
-        r->cname = result->dnsnaptr_cname;
-        r->qname = result->dnsnaptr_qname;
-        r->ttl = result->dnsnaptr_ttl;
-        for (int i = 0; i < result->dnsnaptr_nrr; i++) {
-            if( !r->qservice.empty() && r->qservice != result->dnsnaptr_naptr[i].service )
-                continue;
+        if (!r->isCancelled()) {
+            r->cname = result->dnsnaptr_cname;
+            r->qname = result->dnsnaptr_qname;
+            r->ttl = result->dnsnaptr_ttl;
+            for (int i = 0; i < result->dnsnaptr_nrr; i++) {
+                if (!r->qservice.empty() && r->qservice != result->dnsnaptr_naptr[i].service)
+                    continue;
 
-            //TODO: case ignore and result flags may have more than one flag
-            if( !r->qflags.empty() && r->qflags != result->dnsnaptr_naptr[i].flags )
-                continue;
+                //TODO: case ignore and result flags may have more than one flag
+                if (!r->qflags.empty() && r->qflags != result->dnsnaptr_naptr[i].flags)
+                    continue;
 
-            NAPTRRequest::NAPTR_ptr naptr(new NAPTRRequest::NAPTR);
-            r->entries.push_back(naptr);
-            naptr->order = result->dnsnaptr_naptr[i].order;
-            naptr->preference = result->dnsnaptr_naptr[i].preference;
-            naptr->flags = result->dnsnaptr_naptr[i].flags;
-            naptr->service = result->dnsnaptr_naptr[i].service;
-            naptr->regexp = result->dnsnaptr_naptr[i].regexp;
-            naptr->replacement = result->dnsnaptr_naptr[i].replacement;
+                NAPTRRequest::NAPTR_ptr naptr(new NAPTRRequest::NAPTR);
+                r->entries.push_back(naptr);
+                naptr->order = result->dnsnaptr_naptr[i].order;
+                naptr->preference = result->dnsnaptr_naptr[i].preference;
+                naptr->flags = result->dnsnaptr_naptr[i].flags;
+                naptr->service = result->dnsnaptr_naptr[i].service;
+                naptr->regexp = result->dnsnaptr_naptr[i].regexp;
+                naptr->replacement = result->dnsnaptr_naptr[i].replacement;
+            }
+            std::sort(r->entries.begin(), r->entries.end(), sortNAPTR);
         }
-        std::sort( r->entries.begin(), r->entries.end(), sortNAPTR );
         free(result);
     }
     r->setComplete();
@@ -223,11 +245,13 @@ static void dnscbNAPTR(struct dns_ctx *ctx, struct dns_rr_naptr *result, void *d
 
 void NAPTRRequest::submit( Client * client )
 {
-    if (!dns_submit_naptr(client->d->ctx, getDn().c_str(), 0, dnscbNAPTR, this )) {
+    auto q = dns_submit_naptr(client->d->ctx, getDn().c_str(), 0, dnscbNAPTR, this);
+    if (!q) {
         SG_LOG(SG_IO, SG_ALERT, "Can't submit dns request for " << getDn());
         return;
     }
     _start = time(NULL);
+    _query = q;
 }
 
 
@@ -242,6 +266,7 @@ Client::Client() :
 
 void Client::makeRequest(const Request_ptr& r)
 {
+    d->_activeRequests.push_back(r);
     r->submit(this);
 }
 
@@ -252,6 +277,19 @@ void Client::update(int waitTimeout)
         return;
 
     dns_ioevent(d->ctx, now);
+
+    // drop our owning ref to completed requests,
+    // and cancel any which timed out
+    auto it = std::remove_if(d->_activeRequests.begin(), d->_activeRequests.end(),
+                             [this](const Request_ptr& r) {
+                                 if (r->isTimeout()) {
+                                     dns_cancel(d->ctx, reinterpret_cast<struct dns_query*>(r->_query));
+                                     return true;
+                                 }
+
+                                 return r->isComplete();
+                             });
+    d->_activeRequests.erase(it, d->_activeRequests.end());
 }
 
 } // of namespace DNS

simgear/io/DNSClient.hxx

@@ -40,28 +40,38 @@ namespace DNS
 {
 
 class Client;
+
+using UDNSQueryPtr = void*;
+
 class Request : public SGReferenced
 {
 public:
     Request( const std::string & dn );
     virtual ~Request();
-    std::string getDn() const { return _dn; }
+    const std::string& getDn() const { return _dn; }
     int getType() const { return _type; }
     bool isComplete() const { return _complete; }
     bool isTimeout() const;
     void setComplete( bool b = true ) { _complete = b; }
+    bool isCancelled() const { return _cancelled; }
 
     virtual void submit( Client * client) = 0;
 
+    void cancel();
+
     std::string cname;
     std::string qname;
     unsigned ttl;
 protected:
+    friend class Client;
+
+    UDNSQueryPtr _query = nullptr;
     std::string _dn;
     int _type;
     bool _complete;
     time_t _timeout_secs;
     time_t _start;
+    bool _cancelled = false;
 };
 typedef SGSharedPtr<Request> Request_ptr;
 
@@ -69,7 +79,7 @@ class NAPTRRequest : public Request
 {
 public:
     NAPTRRequest( const std::string & dn );
-    virtual void submit( Client * client );
+    void submit(Client* client) override;
 
     struct NAPTR : SGReferenced {
         int order;
@@ -92,7 +102,7 @@ class SRVRequest : public Request
 public:
     SRVRequest( const std::string & dn );
     SRVRequest( const std::string & dn, const string & service, const string & protocol );
-    virtual void submit( Client * client );
+    void submit(Client* client) override;
 
     struct SRV : SGReferenced {
       int priority;
@@ -112,7 +122,7 @@ class TXTRequest : public Request
 {
 public:
     TXTRequest( const std::string & dn );
-    virtual void submit( Client * client );
+    void submit(Client* client) override;
 
     typedef std::vector<string> TXT_list;
     typedef std::map<std::string,std::string> TXT_Attribute_map;

simgear/io/HTTPRepository.cxx

@@ -81,6 +81,45 @@ std::string innerResultCodeAsString(HTTPRepository::ResultCode code) {
   return "Unknown response code";
 }
 
+struct HashCacheEntry {
+    std::string filePath;
+    time_t modTime;
+    size_t lengthBytes;
+    std::string hashHex;
+};
+
+using HashCache = std::unordered_map<std::string, HashCacheEntry>;
+
+std::string computeHashForPath(const SGPath& p)
+{
+    if (!p.exists())
+        return {};
+
+    sha1nfo info;
+    sha1_init(&info);
+
+    const int bufSize = 1024 * 1024;
+    char* buf = static_cast<char*>(malloc(bufSize));
+    if (!buf) {
+        sg_io_exception("Couldn't allocate SHA1 computation buffer");
+    }
+
+    size_t readLen;
+    SGBinaryFile f(p);
+    if (!f.open(SG_IO_IN)) {
+        free(buf);
+        throw sg_io_exception("Couldn't open file for compute hash", p);
+    }
+    while ((readLen = f.read(buf, bufSize)) > 0) {
+        sha1_write(&info, buf, readLen);
+    }
+
+    f.close();
+    free(buf);
+    std::string hashBytes((char*)sha1_result(&info), HASH_LENGTH);
+    return strutils::encodeHex(hashBytes);
+}
+
 } // namespace
 
 class HTTPDirectory
@@ -111,6 +150,9 @@ class HTTPDirectory
     typedef std::vector<ChildInfo> ChildInfoList;
     ChildInfoList children;
 
+    mutable HashCache hashes;
+    mutable bool hashCacheDirty = false;
+
 public:
     HTTPDirectory(HTTPRepoPrivate* repo, const std::string& path) :
         _repository(repo),
@@ -124,6 +166,8 @@ public:
               // already exists on disk
               parseDirIndex(children);
               std::sort(children.begin(), children.end());
+
+              parseHashCache();
           } catch (sg_exception& ) {
               // parsing cache failed
               children.clear();
@@ -149,7 +193,7 @@ public:
     {
         SGPath fpath(absolutePath());
         fpath.append(".dirindex");
-        _repository->updatedFileContents(fpath, hash);
+        updatedFileContents(fpath, hash);
 
         children.clear();
         parseDirIndex(children);
@@ -177,7 +221,7 @@ public:
 		char* buf = nullptr;
 		size_t bufSize = 0;
 
-		for (const auto& child : children) {
+                for (auto &child : children) {
                   if (child.type != HTTPRepository::FileType)
                     continue;
 
@@ -189,30 +233,36 @@ public:
                   cp.append(child.name);
                   if (!cp.exists()) {
                     continue;
-			}
+                  }
 
-			SGBinaryFile src(cp);
-			SGBinaryFile dst(child.path);
-			src.open(SG_IO_IN);
-			dst.open(SG_IO_OUT);
+                  SGBinaryFile src(cp);
+                  SGBinaryFile dst(child.path);
+                  src.open(SG_IO_IN);
+                  dst.open(SG_IO_OUT);
 
-			if (bufSize < cp.sizeInBytes()) {
-				bufSize = cp.sizeInBytes();
-				free(buf);
-				buf = (char*) malloc(bufSize);
-				if (!buf) {
-					continue;
-				}
-			}
+                  if (bufSize < cp.sizeInBytes()) {
+                    bufSize = cp.sizeInBytes();
+                    free(buf);
+                    buf = (char *)malloc(bufSize);
+                    if (!buf) {
+                      continue;
+                    }
+                  }
 
-			src.read(buf, cp.sizeInBytes());
-			dst.write(buf, cp.sizeInBytes());
-			src.close();
-			dst.close();
+                  src.read(buf, cp.sizeInBytes());
+                  dst.write(buf, cp.sizeInBytes());
+                  src.close();
+                  dst.close();
 
-		}
+                  // reset caching
+                  child.path.set_cached(false);
+                  child.path.set_cached(true);
 
-		free(buf);
+                  std::string hash = computeHashForPath(child.path);
+                  updatedFileContents(child.path, hash);
+                }
+
+                free(buf);
     }
 
     void updateChildrenBasedOnHash()
@@ -274,7 +324,7 @@ public:
           if (c.type == HTTPRepository::DirectoryType) {
             // If it's a directory,perform a recursive check.
             HTTPDirectory *childDir = childDirectory(c.name);
-            childDir->updateChildrenBasedOnHash();
+            _repository->scheduleUpdateOfChildren(childDir);
           }
         }
       } // of repository-defined (well, .dirIndex) children iteration
@@ -372,6 +422,71 @@ public:
         return _relativePath;
     }
 
+    class ArchiveExtractTask {
+    public:
+      ArchiveExtractTask(SGPath p, const std::string &relPath)
+          : relativePath(relPath), file(p), extractor(p.dir()) {
+        if (!file.open(SG_IO_IN)) {
+          SG_LOG(SG_TERRASYNC, SG_ALERT,
+                 "Unable to open " << p << " to extract");
+          return;
+        }
+
+        buffer = (uint8_t *)malloc(bufferSize);
+      }
+
+      ArchiveExtractTask(const ArchiveExtractTask &) = delete;
+
+      HTTPRepoPrivate::ProcessResult run(HTTPRepoPrivate* repo)
+      {
+          if (!buffer) {
+              return HTTPRepoPrivate::ProcessFailed;
+          }
+
+          size_t rd = file.read((char*)buffer, bufferSize);
+          extractor.extractBytes(buffer, rd);
+
+          if (file.eof()) {
+              extractor.flush();
+              file.close();
+
+              if (!extractor.isAtEndOfArchive()) {
+                  SG_LOG(SG_TERRASYNC, SG_ALERT, "Corrupt tarball " << relativePath);
+                  repo->failedToUpdateChild(relativePath,
+                                            HTTPRepository::REPO_ERROR_IO);
+                  return HTTPRepoPrivate::ProcessFailed;
+              }
+
+              if (extractor.hasError()) {
+                  SG_LOG(SG_TERRASYNC, SG_ALERT, "Error extracting " << relativePath);
+                  repo->failedToUpdateChild(relativePath,
+                                            HTTPRepository::REPO_ERROR_IO);
+                  return HTTPRepoPrivate::ProcessFailed;
+              }
+
+              return HTTPRepoPrivate::ProcessDone;
+          }
+
+          return HTTPRepoPrivate::ProcessContinue;
+      }
+
+      ~ArchiveExtractTask() { free(buffer); }
+
+    private:
+      // intentionally small so we extract incrementally on Windows
+      // where Defender throttles many small files, sorry
+      // if you make this bigger we will be more efficient but stall for
+      // longer when extracting the Airports_archive
+      const int bufferSize = 1024 * 64;
+
+      std::string relativePath;
+      uint8_t *buffer = nullptr;
+      SGBinaryFile file;
+      ArchiveExtractor extractor;
+    };
+
+    using ArchiveExtractTaskPtr = std::shared_ptr<ArchiveExtractTask>;
+
     void didUpdateFile(const std::string& file, const std::string& hash, size_t sz)
     {
         // check hash matches what we expected
@@ -387,7 +502,7 @@ public:
                     _relativePath + "/" + file,
                     HTTPRepository::REPO_ERROR_CHECKSUM);
             } else {
-                _repository->updatedFileContents(it->path, hash);
+                updatedFileContents(it->path, hash);
                 _repository->updatedChildSuccessfully(_relativePath + "/" +
                                                       file);
 
@@ -410,33 +525,22 @@ public:
                   }
 
                   if (pathAvailable) {
-                    // If this is a tarball, then extract it.
-                    SGBinaryFile f(p);
-                    if (! f.open(SG_IO_IN)) SG_LOG(SG_TERRASYNC, SG_ALERT, "Unable to open " << p << " to extract");
+                    // we use a Task helper to extract tarballs incrementally.
+                    // without this, archive extraction blocks here, which
+                    // prevents other repositories downloading / updating.
+                    // Unfortunately due Windows AV (Defender, etc) we cna block
+                    // here for many minutes.
 
-                    SG_LOG(SG_TERRASYNC, SG_INFO, "Extracting " << absolutePath() << "/" << file << " to " << p.dir());
-                    SGPath extractDir = p.dir();
-                    ArchiveExtractor ex(extractDir);
-
-                    uint8_t *buf = (uint8_t *)alloca(2048);
-                    while (!f.eof()) {
-                      size_t bufSize = f.read((char *)buf, 2048);
-                      ex.extractBytes(buf, bufSize);
-                    }
-
-                    ex.flush();
-                    if (! ex.isAtEndOfArchive()) {
-                      SG_LOG(SG_TERRASYNC, SG_ALERT, "Corrupt tarball " << p);
-                      _repository->failedToUpdateChild(
-                          _relativePath, HTTPRepository::REPO_ERROR_IO);
-                    }
-
-                    if (ex.hasError()) {
-                      SG_LOG(SG_TERRASYNC, SG_ALERT, "Error extracting " << p);
-                      _repository->failedToUpdateChild(
-                          _relativePath, HTTPRepository::REPO_ERROR_IO);
-                    }
+                    // use a lambda to own this shared_ptr; this means when the
+                    // lambda is destroyed, the ArchiveExtraTask will get
+                    // cleaned up.
+                    ArchiveExtractTaskPtr t =
+                        std::make_shared<ArchiveExtractTask>(p, _relativePath);
+                    auto cb = [t](HTTPRepoPrivate *repo) {
+                      return t->run(repo);
+                    };
 
+                    _repository->addTask(cb);
                   } else {
                     SG_LOG(SG_TERRASYNC, SG_ALERT, "Unable to remove old file/directory " << removePath);
                   } // of pathAvailable
@@ -452,6 +556,50 @@ public:
         fpath.append(file);
         _repository->failedToUpdateChild(fpath, status);
     }
+
+    std::string hashForPath(const SGPath& p) const
+    {
+        const auto ps = p.utf8Str();
+        auto it = hashes.find(ps);
+        if (it != hashes.end()) {
+            const auto& entry = it->second;
+            // ensure data on disk hasn't changed.
+            // we could also use the file type here if we were paranoid
+            if ((p.sizeInBytes() == entry.lengthBytes) && (p.modTime() == entry.modTime)) {
+                return entry.hashHex;
+            }
+
+            // entry in the cache, but it's stale so remove and fall through
+            hashes.erase(it);
+        }
+
+        std::string hash = computeHashForPath(p);
+        updatedFileContents(p, hash);
+        return hash;
+    }
+
+    bool isHashCacheDirty() const
+    {
+        return hashCacheDirty;
+    }
+
+    void writeHashCache() const
+    {
+        if (!hashCacheDirty)
+            return;
+
+        hashCacheDirty = false;
+
+        SGPath cachePath = absolutePath() / ".dirhash";
+        sg_ofstream stream(cachePath, std::ios::out | std::ios::trunc | std::ios::binary);
+        for (const auto& e : hashes) {
+            const auto& entry = e.second;
+            stream << entry.filePath << "*" << entry.modTime << "*"
+                   << entry.lengthBytes << "*" << entry.hashHex << "\n";
+        }
+        stream.close();
+    }
+
 private:
 
     struct ChildWithName
@@ -575,7 +723,7 @@ private:
             ok = _repository->deleteDirectory(fpath, path);
         } else {
             // remove the hash cache entry
-            _repository->updatedFileContents(path, std::string());
+            updatedFileContents(path, std::string());
             ok = path.remove();
         }
 
@@ -593,9 +741,80 @@ private:
       if (child.type == HTTPRepository::TarballType)
         p.concat(
             ".tgz"); // For tarballs the hash is against the tarball file itself
-      return _repository->hashForPath(p);
+      return hashForPath(p);
     }
 
+    void parseHashCache()
+    {
+        hashes.clear();
+        SGPath cachePath = absolutePath() / ".dirhash";
+        if (!cachePath.exists()) {
+            return;
+        }
+
+        sg_ifstream stream(cachePath, std::ios::in);
+
+        while (!stream.eof()) {
+            std::string line;
+            std::getline(stream, line);
+            line = simgear::strutils::strip(line);
+            if (line.empty() || line[0] == '#')
+                continue;
+
+            string_list tokens = simgear::strutils::split(line, "*");
+            if (tokens.size() < 4) {
+                SG_LOG(SG_TERRASYNC, SG_WARN, "invalid entry in '" << cachePath << "': '" << line << "' (ignoring line)");
+                continue;
+            }
+            const std::string nameData = simgear::strutils::strip(tokens[0]);
+            const std::string timeData = simgear::strutils::strip(tokens[1]);
+            const std::string sizeData = simgear::strutils::strip(tokens[2]);
+            const std::string hashData = simgear::strutils::strip(tokens[3]);
+
+            if (nameData.empty() || timeData.empty() || sizeData.empty() || hashData.empty()) {
+                SG_LOG(SG_TERRASYNC, SG_WARN, "invalid entry in '" << cachePath << "': '" << line << "' (ignoring line)");
+                continue;
+            }
+
+            HashCacheEntry entry;
+            entry.filePath = nameData;
+            entry.hashHex = hashData;
+            entry.modTime = strtol(timeData.c_str(), NULL, 10);
+            entry.lengthBytes = strtol(sizeData.c_str(), NULL, 10);
+            hashes.insert(std::make_pair(entry.filePath, entry));
+        }
+    }
+
+    void updatedFileContents(const SGPath& p, const std::string& newHash) const
+    {
+        // remove the existing entry
+        const auto ps = p.utf8Str();
+        auto it = hashes.find(ps);
+        if (it != hashes.end()) {
+            hashes.erase(it);
+            hashCacheDirty = true;
+        }
+
+        if (newHash.empty()) {
+            return; // we're done
+        }
+
+        // use a cloned SGPath and reset its caching to force one stat() call
+        SGPath p2(p);
+        p2.set_cached(false);
+        p2.set_cached(true);
+
+        HashCacheEntry entry;
+        entry.filePath = ps;
+        entry.hashHex = newHash;
+        entry.modTime = p2.modTime();
+        entry.lengthBytes = p2.sizeInBytes();
+        hashes.insert(std::make_pair(ps, entry));
+
+        hashCacheDirty = true;
+    }
+
+
     HTTPRepoPrivate* _repository;
     std::string _relativePath; // in URL and file-system space
 };
@@ -606,7 +825,6 @@ HTTPRepository::HTTPRepository(const SGPath& base, HTTP::Client *cl) :
     _d->http = cl;
     _d->basePath = base;
     _d->rootDir.reset(new HTTPDirectory(_d.get(), ""));
-    _d->parseHashCache();
 }
 
 HTTPRepository::~HTTPRepository()
@@ -654,6 +872,38 @@ bool HTTPRepository::isDoingSync() const
     return _d->isUpdating;
 }
 
+void HTTPRepository::process()
+{
+    int processedCount = 0;
+    const int maxToProcess = 16;
+
+    while (processedCount < maxToProcess) {
+      if (_d->pendingTasks.empty()) {
+        break;
+      }
+
+      auto task = _d->pendingTasks.front();
+      auto result = task(_d.get());
+      if (result == HTTPRepoPrivate::ProcessContinue) {
+        // assume we're not complete
+        return;
+      }
+
+      _d->pendingTasks.pop_front();
+      ++processedCount;
+    }
+
+    _d->checkForComplete();
+}
+
+void HTTPRepoPrivate::checkForComplete()
+{
+  if (pendingTasks.empty() && activeRequests.empty() &&
+      queuedRequests.empty()) {
+    isUpdating = false;
+  }
+}
+
 size_t HTTPRepository::bytesToDownload() const
 {
     size_t result = 0;
@@ -731,49 +981,71 @@ HTTPRepository::failure() const
         }
 
     protected:
-      void gotBodyData(const char *s, int n) override {
-        if (!file.get()) {
-          file.reset(new SGBinaryFile(pathInRepo));
-          if (!file->open(SG_IO_OUT)) {
-            SG_LOG(SG_TERRASYNC, SG_WARN,
-                   "unable to create file " << pathInRepo);
-            _directory->repository()->http->cancelRequest(
-                this, "Unable to create output file:" + pathInRepo.utf8Str());
-          }
+        void gotBodyData(const char* s, int n) override
+        {
+            if (!file.get()) {
+                const bool ok = createOutputFile();
+                if (!ok) {
+                    _directory->repository()->http->cancelRequest(
+                        this, "Unable to create output file:" + pathInRepo.utf8Str());
+                }
+            }
 
-          sha1_init(&hashContext);
+            sha1_write(&hashContext, s, n);
+            file->write(s, n);
         }
 
-        sha1_write(&hashContext, s, n);
-        file->write(s, n);
-      }
+        bool createOutputFile()
+        {
+            file.reset(new SGBinaryFile(pathInRepo));
+            if (!file->open(SG_IO_OUT)) {
+                SG_LOG(SG_TERRASYNC, SG_WARN,
+                       "unable to create file " << pathInRepo);
+                return false;
+            }
 
-      void onDone() override {
-        file->close();
-        if (responseCode() == 200) {
-          std::string hash =
-              strutils::encodeHex(sha1_result(&hashContext), HASH_LENGTH);
-          _directory->didUpdateFile(fileName, hash, contentSize());
-        } else if (responseCode() == 404) {
-          SG_LOG(SG_TERRASYNC, SG_WARN,
-                 "terrasync file not found on server: "
-                     << fileName << " for " << _directory->absolutePath());
-          _directory->didFailToUpdateFile(
-              fileName, HTTPRepository::REPO_ERROR_FILE_NOT_FOUND);
-        } else {
-          SG_LOG(SG_TERRASYNC, SG_WARN,
-                 "terrasync file download error on server: "
-                     << fileName << " for " << _directory->absolutePath()
-                     << "\n\tserver responded: " << responseCode() << "/"
-                     << responseReason());
-          _directory->didFailToUpdateFile(fileName,
-                                          HTTPRepository::REPO_ERROR_HTTP);
-          // should we every retry here?
+            sha1_init(&hashContext);
+            return true;
         }
 
-        _directory->repository()->finishedRequest(
-            this, HTTPRepoPrivate::RequestFinish::Done);
-      }
+        void onDone() override
+        {
+            const bool is200Response = (responseCode() == 200);
+            if (!file && is200Response) {
+                // if the server defines a zero-byte file, we will never call
+                // gotBodyData, so create the file here
+                // this ensures all the logic below works as expected
+                createOutputFile();
+            }
+
+            if (file) {
+                file->close();
+            }
+
+            if (is200Response) {
+                std::string hash =
+                    strutils::encodeHex(sha1_result(&hashContext), HASH_LENGTH);
+                _directory->didUpdateFile(fileName, hash, contentSize());
+            } else if (responseCode() == 404) {
+                SG_LOG(SG_TERRASYNC, SG_WARN,
+                       "terrasync file not found on server: "
+                           << fileName << " for " << _directory->absolutePath());
+                _directory->didFailToUpdateFile(
+                    fileName, HTTPRepository::REPO_ERROR_FILE_NOT_FOUND);
+            } else {
+                SG_LOG(SG_TERRASYNC, SG_WARN,
+                       "terrasync file download error on server: "
+                           << fileName << " for " << _directory->absolutePath()
+                           << "\n\tserver responded: " << responseCode() << "/"
+                           << responseReason());
+                _directory->didFailToUpdateFile(fileName,
+                                                HTTPRepository::REPO_ERROR_HTTP);
+                // should we every retry here?
+            }
+
+            _directory->repository()->finishedRequest(
+                this, HTTPRepoPrivate::RequestFinish::Done);
+        }
 
       void onFail() override {
         HTTPRepository::ResultCode code = HTTPRepository::REPO_ERROR_SOCKET;
@@ -868,7 +1140,7 @@ HTTPRepository::failure() const
               return;
             }
 
-            std::string curHash = _directory->repository()->hashForPath(path());
+            std::string curHash = _directory->hashForPath(path());
             if (hash != curHash) {
               simgear::Dir d(_directory->absolutePath());
               if (!d.exists()) {
@@ -967,6 +1239,7 @@ HTTPRepository::failure() const
             http->cancelRequest(*rq, "Repository object deleted");
         }
 
+        flushHashCaches();
         directories.clear(); // wil delete them all
     }
 
@@ -986,154 +1259,6 @@ HTTPRepository::failure() const
         return r;
     }
 
-
-    class HashEntryWithPath
-    {
-    public:
-        HashEntryWithPath(const SGPath& p) : path(p.utf8Str()) {}
-        bool operator()(const HTTPRepoPrivate::HashCacheEntry& entry) const
-        { return entry.filePath == path; }
-    private:
-        std::string path;
-    };
-
-    std::string HTTPRepoPrivate::hashForPath(const SGPath& p)
-    {
-        HashCache::iterator it = std::find_if(hashes.begin(), hashes.end(), HashEntryWithPath(p));
-        if (it != hashes.end()) {
-            // ensure data on disk hasn't changed.
-            // we could also use the file type here if we were paranoid
-            if ((p.sizeInBytes() == it->lengthBytes) && (p.modTime() == it->modTime)) {
-                return it->hashHex;
-            }
-
-            // entry in the cache, but it's stale so remove and fall through
-            hashes.erase(it);
-        }
-
-        std::string hash = computeHashForPath(p);
-        updatedFileContents(p, hash);
-        return hash;
-    }
-
-    std::string HTTPRepoPrivate::computeHashForPath(const SGPath& p)
-    {
-        if (!p.exists())
-            return {};
-
-        sha1nfo info;
-        sha1_init(&info);
-
-        const int bufSize = 1024 * 1024;
-        char* buf = static_cast<char*>(malloc(bufSize));
-        if (!buf) {
-            sg_io_exception("Couldn't allocate SHA1 computation buffer");
-        }
-
-        size_t readLen;
-        SGBinaryFile f(p);
-        if (!f.open(SG_IO_IN)) {
-            free(buf);
-            throw sg_io_exception("Couldn't open file for compute hash", p);
-        }
-        while ((readLen = f.read(buf, bufSize)) > 0) {
-            sha1_write(&info, buf, readLen);
-        }
-
-        f.close();
-        free(buf);
-        std::string hashBytes((char*) sha1_result(&info), HASH_LENGTH);
-        return strutils::encodeHex(hashBytes);
-    }
-
-    void HTTPRepoPrivate::updatedFileContents(const SGPath& p, const std::string& newHash)
-    {
-        // remove the existing entry
-        auto it = std::find_if(hashes.begin(), hashes.end(), HashEntryWithPath(p));
-        if (it != hashes.end()) {
-            hashes.erase(it);
-            ++hashCacheDirty;
-        }
-
-        if (newHash.empty()) {
-            return; // we're done
-        }
-
-        // use a cloned SGPath and reset its caching to force one stat() call
-        SGPath p2(p);
-        p2.set_cached(false);
-        p2.set_cached(true);
-
-        HashCacheEntry entry;
-        entry.filePath = p.utf8Str();
-        entry.hashHex = newHash;
-        entry.modTime = p2.modTime();
-        entry.lengthBytes = p2.sizeInBytes();
-        hashes.push_back(entry);
-
-        ++hashCacheDirty ;
-    }
-
-    void HTTPRepoPrivate::writeHashCache()
-    {
-        if (hashCacheDirty == 0) {
-            return;
-        }
-
-        SGPath cachePath = basePath;
-        cachePath.append(".hashes");
-        sg_ofstream stream(cachePath, std::ios::out | std::ios::trunc | std::ios::binary);
-        HashCache::const_iterator it;
-        for (it = hashes.begin(); it != hashes.end(); ++it) {
-            stream << it->filePath << "*" << it->modTime << "*"
-            << it->lengthBytes << "*" << it->hashHex << "\n";
-        }
-        stream.close();
-        hashCacheDirty = 0;
-    }
-
-    void HTTPRepoPrivate::parseHashCache()
-    {
-        hashes.clear();
-        SGPath cachePath = basePath;
-        cachePath.append(".hashes");
-        if (!cachePath.exists()) {
-            return;
-        }
-
-        sg_ifstream stream(cachePath, std::ios::in);
-
-        while (!stream.eof()) {
-            std::string line;
-            std::getline(stream,line);
-            line = simgear::strutils::strip(line);
-            if( line.empty() || line[0] == '#' )
-                continue;
-
-			string_list tokens = simgear::strutils::split(line, "*");
-            if( tokens.size() < 4 ) {
-                SG_LOG(SG_TERRASYNC, SG_WARN, "invalid entry in '" << cachePath << "': '" << line << "' (ignoring line)");
-                continue;
-            }
-            const std::string nameData = simgear::strutils::strip(tokens[0]);
-            const std::string timeData = simgear::strutils::strip(tokens[1]);
-            const std::string sizeData = simgear::strutils::strip(tokens[2]);
-            const std::string hashData = simgear::strutils::strip(tokens[3]);
-
-            if (nameData.empty() || timeData.empty() || sizeData.empty() || hashData.empty() ) {
-                SG_LOG(SG_TERRASYNC, SG_WARN, "invalid entry in '" << cachePath << "': '" << line << "' (ignoring line)");
-                continue;
-            }
-
-            HashCacheEntry entry;
-            entry.filePath = nameData;
-            entry.hashHex = hashData;
-            entry.modTime = strtol(timeData.c_str(), NULL, 10);
-            entry.lengthBytes = strtol(sizeData.c_str(), NULL, 10);
-            hashes.push_back(entry);
-        }
-    }
-
     class DirectoryWithPath
     {
     public:
@@ -1163,16 +1288,12 @@ HTTPRepository::failure() const
         if (it != directories.end()) {
           assert((*it)->absolutePath() == absPath);
           directories.erase(it);
-                } else {
-			// we encounter this code path when deleting an orphaned directory
-		}
+        } else {
+            // we encounter this code path when deleting an orphaned directory
+        }
 
-		Dir dir(absPath);
+        Dir dir(absPath);
 		bool result = dir.remove(true);
-
-		// update the hash cache too
-		updatedFileContents(absPath, std::string());
-
         return result;
     }
 
@@ -1208,17 +1329,10 @@ HTTPRepository::failure() const
         http->makeRequest(rr);
       }
 
-      // rate limit how often we write this, since otherwise
-      // it dominates the time on Windows. 256 seems about right,
-      // causes a write a few times a minute.
-      if (hashCacheDirty > 256) {
-        writeHashCache();
-      }
-
-      if (activeRequests.empty() && queuedRequests.empty()) {
-        isUpdating = false;
-        writeHashCache();
+      if (countDirtyHashCaches() > 32) {
+          flushHashCaches();
       }
+      checkForComplete();
     }
 
     void HTTPRepoPrivate::failedToGetRootIndex(HTTPRepository::ResultCode st)
@@ -1279,4 +1393,38 @@ HTTPRepository::failure() const
           failures.end());
     }
 
+    void HTTPRepoPrivate::scheduleUpdateOfChildren(HTTPDirectory* dir)
+    {
+      auto updateChildTask = [dir](const HTTPRepoPrivate *) {
+        dir->updateChildrenBasedOnHash();
+        return ProcessDone;
+      };
+
+      addTask(updateChildTask);
+    }
+
+    void HTTPRepoPrivate::addTask(RepoProcessTask task) {
+      pendingTasks.push_back(task);
+    }
+
+    int HTTPRepoPrivate::countDirtyHashCaches() const
+    {
+        int result = rootDir->isHashCacheDirty() ? 1 : 0;
+        for (const auto& dir : directories) {
+            if (dir->isHashCacheDirty()) {
+                ++result;
+            }
+        }
+
+        return result;
+    }
+
+    void HTTPRepoPrivate::flushHashCaches()
+    {
+        rootDir->writeHashCache();
+        for (const auto& dir : directories) {
+            dir->writeHashCache();
+        }
+    }
+
 } // of namespace simgear

simgear/io/HTTPRepository.hxx

@@ -62,6 +62,11 @@ public:
 
   virtual bool isDoingSync() const;
 
+  /**
+        @brief call this periodically to progress non-network tasks
+     */
+  void process();
+
   virtual ResultCode failure() const;
 
   virtual size_t bytesToDownload() const;

simgear/io/HTTPRepository_private.hxx

@@ -19,8 +19,11 @@
 
 #pragma once
 
+#include <deque>
+#include <functional>
 #include <memory>
 #include <string>
+#include <unordered_map>
 
 #include <simgear/io/HTTPClient.hxx>
 #include <simgear/misc/sg_path.hxx>
@@ -48,20 +51,11 @@ protected:
   size_t _contentSize = 0;
 };
 
-typedef SGSharedPtr<HTTPRepoGetRequest> RepoRequestPtr;
+using RepoRequestPtr = SGSharedPtr<HTTPRepoGetRequest>;
 
 class HTTPRepoPrivate {
 public:
-  struct HashCacheEntry {
-    std::string filePath;
-    time_t modTime;
-    size_t lengthBytes;
-    std::string hashHex;
-  };
 
-  typedef std::vector<HashCacheEntry> HashCache;
-  HashCache hashes;
-  int hashCacheDirty = 0;
 
   HTTPRepository::FailureVec failures;
   int maxPermittedFailures = 16;
@@ -89,18 +83,14 @@ public:
   HTTP::Request_ptr updateDir(HTTPDirectory *dir, const std::string &hash,
                               size_t sz);
 
-  std::string hashForPath(const SGPath &p);
-  void updatedFileContents(const SGPath &p, const std::string &newHash);
-  void parseHashCache();
-  std::string computeHashForPath(const SGPath &p);
-  void writeHashCache();
-
   void failedToGetRootIndex(HTTPRepository::ResultCode st);
   void failedToUpdateChild(const SGPath &relativePath,
                            HTTPRepository::ResultCode fileStatus);
 
   void updatedChildSuccessfully(const SGPath &relativePath);
 
+  void checkForComplete();
+
   typedef std::vector<RepoRequestPtr> RequestVector;
   RequestVector queuedRequests, activeRequests;
 
@@ -113,10 +103,24 @@ public:
   HTTPDirectory *getOrCreateDirectory(const std::string &path);
   bool deleteDirectory(const std::string &relPath, const SGPath &absPath);
 
+
   typedef std::vector<HTTPDirectory_ptr> DirectoryVector;
   DirectoryVector directories;
 
+  void scheduleUpdateOfChildren(HTTPDirectory *dir);
+
   SGPath installedCopyPath;
+
+  int countDirtyHashCaches() const;
+  void flushHashCaches();
+
+  enum ProcessResult { ProcessContinue, ProcessDone, ProcessFailed };
+
+  using RepoProcessTask = std::function<ProcessResult(HTTPRepoPrivate *repo)>;
+
+  void addTask(RepoProcessTask task);
+
+  std::deque<RepoProcessTask> pendingTasks;
 };
 
 } // namespace simgear

simgear/io/iostreams/gzfstream.cxx

@@ -185,6 +185,9 @@ gzfilebuf::setcompressionstrategy( int comp_strategy )
 
 z_off_t
 gzfilebuf::approxOffset() {
+    #ifdef __OpenBSD__
+    z_off_t res = 0;
+    #else
     z_off_t res = gzoffset(file);
 
     if (res == -1) {
@@ -201,7 +204,7 @@ gzfilebuf::approxOffset() {
         SG_LOG( SG_GENERAL, SG_ALERT, errMsg );
         throw sg_io_exception(errMsg);
     }
-
+    #endif
     return res;
 }
 

simgear/io/sg_binobj.cxx

@@ -42,6 +42,7 @@
 
 #include <simgear/bucket/newbucket.hxx>
 #include <simgear/misc/sg_path.hxx>
+#include <simgear/misc/strutils.hxx>
 #include <simgear/math/SGGeometry.hxx>
 #include <simgear/structure/exception.hxx>
 
@@ -563,6 +564,14 @@ bool SGBinObject::read_bin( const SGPath& file ) {
     // read headers
     unsigned int header;
     sgReadUInt( fp, &header );
+
+    if (sgReadError()) {
+        int code = 0;
+        const char* gzErrorString = gzerror(fp, &code);
+        gzclose(fp);
+        throw sg_io_exception("Unable to read BTG header: " + string{gzErrorString} + ", code =" + std::to_string(code), sg_location(file));
+    }
+
     if ( ((header & 0xFF000000) >> 24) == 'S' &&
          ((header & 0x00FF0000) >> 16) == 'G' ) {
 

simgear/io/test_repository.cxx

@@ -31,6 +31,10 @@ using TestApi = simgear::HTTP::TestApi;
 
 std::string dataForFile(const std::string& parentName, const std::string& name, int revision)
 {
+    if (name == "zeroByteFile") {
+        return {};
+    }
+
     std::ostringstream os;
     // random content but which definitely depends on our tree location
     // and revision.
@@ -409,6 +413,7 @@ void waitForUpdateComplete(HTTP::Client* cl, HTTPRepository* repo)
         cl->update();
         testServer.poll();
 
+        repo->process();
         if (!repo->isDoingSync()) {
             return;
         }
@@ -423,6 +428,7 @@ void runForTime(HTTP::Client *cl, HTTPRepository *repo, int msec = 15) {
   while (start.elapsedMSec() < msec) {
     cl->update();
     testServer.poll();
+    repo->process();
     SGTimeStamp::sleepForMSec(1);
   }
 }
@@ -444,6 +450,7 @@ void testBasicClone(HTTP::Client* cl)
     verifyFileState(p, "fileA");
     verifyFileState(p, "dirA/subdirA/fileAAA");
     verifyFileState(p, "dirC/subdirA/subsubA/fileCAAA");
+    verifyFileState(p, "dirA/subdirA/zeroByteFile");
 
     global_repo->findEntry("fileA")->revision++;
     global_repo->findEntry("dirB/subdirA/fileBAA")->revision++;
@@ -909,6 +916,8 @@ int main(int argc, char* argv[])
     global_repo->defineFile("dirA/fileAC");
     global_repo->defineFile("dirA/subdirA/fileAAA");
     global_repo->defineFile("dirA/subdirA/fileAAB");
+    global_repo->defineFile("dirA/subdirA/zeroByteFile");
+
     global_repo->defineFile("dirB/subdirA/fileBAA");
     global_repo->defineFile("dirB/subdirA/fileBAB");
     global_repo->defineFile("dirB/subdirA/fileBAC");

simgear/io/untar.cxx

@@ -31,6 +31,8 @@
 #include <simgear/sg_inlines.h>
 #include <simgear/io/sg_file.hxx>
 #include <simgear/misc/sg_dir.hxx>
+#include <simgear/misc/strutils.hxx>
+
 #include <simgear/io/iostreams/sgstream.hxx>
 #include <simgear/debug/logstream.hxx>
 #include <simgear/package/unzip.h>
@@ -509,32 +511,34 @@ public:
 		const size_t BUFFER_SIZE = 1024 * 1024;
 		void* buf = malloc(BUFFER_SIZE);
 
-		try {
-			int result = unzGoToFirstFile(zip);
-			if (result != UNZ_OK) {
-				throw sg_exception("failed to go to first file in archive");
-			}
-
-			while (true) {
-				extractCurrentFile(zip, (char*)buf, BUFFER_SIZE);
-				if (state == FILTER_STOPPED) {
-					break;
-				}
-
-				result = unzGoToNextFile(zip);
-				if (result == UNZ_END_OF_LIST_OF_FILE) {
-					break;
-				}
-				else if (result != UNZ_OK) {
-					throw sg_io_exception("failed to go to next file in the archive");
-				}
-			}
-			state = END_OF_ARCHIVE;
-		}
-		catch (sg_exception&) {
+        int result = unzGoToFirstFile(zip);
+        if (result != UNZ_OK) {
+            SG_LOG(SG_IO, SG_ALERT, outer->rootPath() << "failed to go to first file in archive:" << result);
             state = BAD_ARCHIVE;
+            free(buf);
+            unzClose(zip);
+            return;
         }
-        
+
+        while (true) {
+            extractCurrentFile(zip, (char*)buf, BUFFER_SIZE);
+            if (state == FILTER_STOPPED) {
+                state = END_OF_ARCHIVE;
+                break;
+            }
+
+            result = unzGoToNextFile(zip);
+            if (result == UNZ_END_OF_LIST_OF_FILE) {
+                state = END_OF_ARCHIVE;
+                break;
+            } else if (result != UNZ_OK) {
+                SG_LOG(SG_IO, SG_ALERT, outer->rootPath() << "failed to go to next file in archive:" << result);
+                state = BAD_ARCHIVE;
+                break;
+            }
+        }
+
+
         free(buf);
         unzClose(zip);
     }
@@ -592,7 +596,7 @@ public:
 
 		outFile.open(path, std::ios::binary | std::ios::trunc | std::ios::out);
 		if (outFile.fail()) {
-			throw sg_io_exception("failed to open output file for writing", path);
+			throw sg_io_exception("failed to open output file for writing:" + strutils::error_string(errno), path);
 		}
 
 		while (!eof) {

simgear/io/untar.hxx

@@ -70,6 +70,11 @@ public:
 		Stop
 	};
 
+    SGPath rootPath() const
+    {
+        return _rootPath;
+    }
+
 protected:
 
 

simgear/math/SGGeod.hxx

@@ -29,6 +29,13 @@ public:
   /// Default constructor, initializes the instance to lat = lon = elev = 0
   SGGeod(void);
 
+  /**
+    return an SGGeod for which isValid() returns false.
+    This is necessaerby becuase for historical reasons, ther defaulrt constructor above initialsies to zero,zero,zero
+    which *is*
+   */
+  static SGGeod invalid();
+
   /// Factory from angular values in radians and elevation is 0
   static SGGeod fromRad(double lon, double lat);
   /// Factory from angular values in degrees and elevation is 0

simgear/math/SGGeodesy.cxx

@@ -663,3 +663,8 @@ SGGeodesy::radialIntersection(const SGGeod& a, double aRadial,
   result = SGGeod::fromGeoc(r);
   return true;
 }
+
+SGGeod SGGeod::invalid()
+{
+    return SGGeod::fromDeg(-999.9, -999.0);
+}

simgear/nasal/code.c

@@ -248,7 +248,7 @@ void naFreeContext(naContext c)
     // than I have right now. So instead I'm clearing the stack tops here, so
     // a freed context looks the same as a new one returned by initContext.
 
-    c->fTop = c->opTop = c->markTop = 0;
+    c->fTop = c->opTop = c->markTop = c->ntemps = 0;
 
     c->nextFree = globals->freeContexts;
     globals->freeContexts = c;

simgear/nasal/cppbind/NasalEmesaryInterface.hxx

@@ -63,7 +63,7 @@ namespace nasal
 
     class NasalMainLoopRecipient : public simgear::Emesary::IReceiver {
     public:
-        NasalMainLoopRecipient() : receiveCount(0) {
+        NasalMainLoopRecipient() : receiveCount(0), Active(false), CanWait(false) {
             simgear::Emesary::GlobalTransmitter::instance()->Register(*this);
         }
         virtual ~NasalMainLoopRecipient() {

simgear/nasal/misc.c

@@ -100,7 +100,14 @@ naRef naNewHash(struct Context* c)
 
 naRef naNewCode(struct Context* c)
 {
-    return naNew(c, T_CODE);
+    naRef r = naNew(c, T_CODE);
+    // naNew can return a previously used naCode. naCodeGen will init
+    // all these members but a GC can occur inside naCodeGen, so we see
+    // partially initalized state here. To avoid this, clear out the values
+    // which mark() cares about.
+    PTR(r).code->srcFile = naNil();
+    PTR(r).code->nConstants = 0;
+    return r;
 }
 
 naRef naNewCCode(struct Context* c, naCFunction fptr)

simgear/package/Root.cxx

@@ -133,7 +133,9 @@ public:
 
     void fireRefreshStatus(CatalogRef catalog, Delegate::StatusCode status)
     {
-        for (auto d : delegates) {
+        // take a copy of delegates since firing this can modify the data
+        const auto currentDelegates = delegates;
+        for (auto d : currentDelegates) {
             d->catalogRefreshed(catalog, status);
         }
     }
@@ -722,12 +724,6 @@ void Root::catalogRefreshStatus(CatalogRef aCat, Delegate::StatusCode aReason)
     auto catIt = d->catalogs.find(aCat->id());
     d->fireRefreshStatus(aCat, aReason);
 
-    if (aReason == Delegate::STATUS_IN_PROGRESS) {
-        d->refreshing.insert(aCat);
-    } else {
-        d->refreshing.erase(aCat);
-    }
-
     if (aCat->isUserEnabled() &&
         (aReason == Delegate::STATUS_REFRESHED) && 
         (catIt == d->catalogs.end())) 
@@ -761,6 +757,17 @@ void Root::catalogRefreshStatus(CatalogRef aCat, Delegate::StatusCode aReason)
         }
     } // of catalog is disabled
 
+    // remove from refreshing /after/ checking for enable / disabled, since for
+    // new catalogs, the reference in d->refreshing might be our /only/
+    // reference to the catalog. Once the refresh is done (either failed or
+    // succeeded) the Catalog will be in either d->catalogs or
+    // d->disabledCatalogs
+    if (aReason == Delegate::STATUS_IN_PROGRESS) {
+      d->refreshing.insert(aCat);
+    } else {
+      d->refreshing.erase(aCat);
+    }
+
     if (d->refreshing.empty()) {
         d->fireRefreshStatus(CatalogRef(), Delegate::STATUS_REFRESHED);
         d->firePackagesChanged();

simgear/props/AtomicChangeListener.cxx

@@ -59,6 +59,12 @@ void AtomicChangeListener::fireChangeListeners()
     listeners.clear();
 }
 
+void AtomicChangeListener::clearPendingChanges()
+{
+    auto& listeners = ListenerListSingleton::instance()->listeners;
+    listeners.clear();
+}
+
 void AtomicChangeListener::valueChangedImplementation()
 {
     if (!_dirty) {

simgear/props/AtomicChangeListener.hxx

@@ -52,7 +52,17 @@ public:
     bool isDirty() { return _dirty; }
     bool isValid() { return _valid; }
     virtual void unregister_property(SGPropertyNode* node) override;
+
     static void fireChangeListeners();
+
+    /**
+     * @brief Ensure we've deleted any pending changes. 
+     * 
+     * This is important in shutdown and reset, to avoid holding
+     * property listeners around after the property tree is destroyed
+     */
+    static void clearPendingChanges();
+
 private:
     virtual void valueChangedImplementation() override;
     virtual void valuesChanged();

simgear/props/props.cxx

@@ -19,6 +19,10 @@
 #include <sstream>
 #include <iomanip>
 #include <iterator>
+#include <exception> // can't use sg_exception becuase of PROPS_STANDALONE
+#include <mutex>
+#include <thread>
+
 #include <stdio.h>
 #include <string.h>
 
@@ -51,11 +55,15 @@ using namespace simgear;
 
 struct SGPropertyNodeListeners
 {
+  /* Protect _num_iterators and _items. We use a recursive mutex to allow
+  nested access to work as normal. */
+  std::recursive_mutex  _rmutex;
+
   /* This keeps a count of the current number of nested invocations of
   forEachListener(). If non-zero, other code higher up the stack is iterating
   _items[] so for example code must not erase items in the vector. */
   int _num_iterators = 0;
-  
+
   std::vector<SGPropertyChangeListener *> _items;
 };
 
@@ -558,23 +566,15 @@ find_node (SGPropertyNode * current,
   }
 }
 #else
-template<typename Range>
-SGPropertyNode*
-find_node (SGPropertyNode * current,
-           const Range& path,
-           bool create,
-           int last_index = -1)
-{
+template <typename Range>
+SGPropertyNode *find_node(SGPropertyNode *current, const Range &path,
+                          bool create, int last_index = -1) {
   using namespace boost;
-  typedef split_iterator<typename range_result_iterator<Range>::type>
-    PathSplitIterator;
-
-  PathSplitIterator itr
-    = make_split_iterator(path, first_finder("/", is_equal()));
+  auto itr = make_split_iterator(path, first_finder("/", is_equal()));
   if (*path.begin() == '/')
     return find_node_aux(current->getRootNode(), itr, create, last_index);
-   else
-     return find_node_aux(current, itr, create, last_index);
+  else
+    return find_node_aux(current, itr, create, last_index);
 }
 #endif
 
@@ -2406,6 +2406,7 @@ SGPropertyNode::addChangeListener (SGPropertyChangeListener * listener,
   if (_listeners == 0)
     _listeners = new SGPropertyNodeListeners;
 
+  std::lock_guard<std::recursive_mutex> lock(_listeners->_rmutex);
   /* If there's a nullptr entry (a listener that was unregistered), we
   overwrite it. This ensures that listeners that routinely unregister+register
   themselves don't make _listeners->_items grow unnecessarily. Otherwise simply
@@ -2429,9 +2430,13 @@ SGPropertyNode::removeChangeListener (SGPropertyChangeListener * listener)
 {
   if (_listeners == 0)
     return;
+  /* We use a std::unique_lock rather than a std::lock_guard because we may
+  need to unlock early. */
+  std::unique_lock<std::recursive_mutex> lock(_listeners->_rmutex);
   vector<SGPropertyChangeListener*>::iterator it =
     find(_listeners->_items.begin(), _listeners->_items.end(), listener);
   if (it != _listeners->_items.end()) {
+    assert(_listeners->_num_iterators >= 0);
     if (_listeners->_num_iterators) {
       /* _listeners._items is currently being iterated further up the stack in
       this thread by one or more nested invocations of forEachListener(), so
@@ -2450,6 +2455,7 @@ SGPropertyNode::removeChangeListener (SGPropertyChangeListener * listener)
       _listeners->_items.erase(it);
       listener->unregister_property(this);
       if (_listeners->_items.empty()) {
+        lock.unlock();
         delete _listeners;
         _listeners = 0;
       }
@@ -2511,9 +2517,11 @@ static void forEachListener(
     )
 {
   if (!_listeners) return;
-  
+
+  std::lock_guard<std::recursive_mutex> lock(_listeners->_rmutex);
+  assert(_listeners->_num_iterators >= 0);
   _listeners->_num_iterators += 1;
-  
+
   /* We need to use an index here when iterating _listeners->_items, not an
   iterator. This is because a listener may add new listeners, causing the
   vector to be reallocated, which would invalidate any iterator. */
@@ -2528,10 +2536,12 @@ static void forEachListener(
       }
     }
   }
-  
+
   _listeners->_num_iterators -= 1;
-  
+  assert(_listeners->_num_iterators >= 0);
+
   if (_listeners->_num_iterators == 0) {
+
     /* Remove any items that have been set to nullptr. */
     _listeners->_items.erase(
         std::remove(_listeners->_items.begin(), _listeners->_items.end(), (SGPropertyChangeListener*) nullptr),
@@ -2547,6 +2557,7 @@ static void forEachListener(
 int SGPropertyNode::nListeners() const
 {
   if (!_listeners) return 0;
+  std::lock_guard<std::recursive_mutex> lock(_listeners->_rmutex);
   int   n = 0;
   for (auto listener: _listeners->_items) {
     if (listener)   n += 1;

simgear/scene/material/Effect.cxx

@@ -76,7 +76,7 @@
 #include <simgear/structure/SGExpression.hxx>
 #include <simgear/props/props_io.hxx>
 #include <simgear/props/vectorPropTemplates.hxx>
-
+#include <simgear/debug/ErrorReportingCallback.hxx>
 #include <simgear/io/iostreams/sgstream.hxx>
 
 namespace simgear
@@ -928,7 +928,8 @@ void ShaderProgramBuilder::buildAttribute(Effect* effect, Pass* pass,
         // FIXME orig: const string& shaderName = shaderKey.first;
         string shaderName = shaderKey.first;
         Shader::Type stype = (Shader::Type)shaderKey.second;
-        if (getPropertyRoot()->getBoolValue("/sim/version/compositor-support", false) &&
+        const bool compositorEnabled = getPropertyRoot()->getBoolValue("/sim/version/compositor-support", false);
+        if (compositorEnabled &&
             shaderName.substr(0, shaderName.find("/")) == "Shaders") {
             shaderName = "Compositor/" + shaderName;
         }
@@ -936,7 +937,9 @@ void ShaderProgramBuilder::buildAttribute(Effect* effect, Pass* pass,
         if (fileName.empty())
         {
             SG_LOG(SG_INPUT, SG_ALERT, "Could not locate shader" << shaderName);
-
+            if (!compositorEnabled) {
+                reportError("Missing shader", shaderName);
+            }
 
             throw BuilderException(string("couldn't find shader ") +
                 shaderName);
@@ -1481,10 +1484,8 @@ void mergeSchemesFallbacks(Effect *effect, const SGReaderWriterOptions *options)
 
 // Walk the techniques property tree, building techniques and
 // passes.
-static std::mutex  realizeTechniques_lock;
 bool Effect::realizeTechniques(const SGReaderWriterOptions* options)
 {
-    std::lock_guard<std::mutex> g(realizeTechniques_lock);
     if (getPropertyRoot()->getBoolValue("/sim/version/compositor-support", false))
         mergeSchemesFallbacks(this, options);
 

simgear/scene/material/TextureBuilder.cxx

@@ -273,11 +273,19 @@ bool setAttrs(const TexTuple& attrs, Texture* tex,
         options->setLoadOriginHint(SGReaderWriterOptions::LoadOriginHint::ORIGIN_EFFECTS_NORMALIZED);
     else
         options->setLoadOriginHint(SGReaderWriterOptions::LoadOriginHint::ORIGIN_EFFECTS);
-#if OSG_VERSION_LESS_THAN(3,4,2)
-    result = osgDB::readImageFile(imageName, options);
-#else
-    result = osgDB::readRefImageFile(imageName, options);
-#endif
+
+    try {
+    #if OSG_VERSION_LESS_THAN(3,4,2)
+        result = osgDB::readImageFile(imageName, options);
+    #else
+        result = osgDB::readRefImageFile(imageName, options);
+    #endif
+    } catch (std::bad_alloc& ba) {
+        SG_LOG(SG_GL, SG_ALERT, "Bad allocation loading:" << imageName);
+        // todo: report low memory warning
+        return false;
+    }
+
     options->setLoadOriginHint(origLOH);
     osg::ref_ptr<osg::Image> image;
     if (result.success())

simgear/scene/model/ModelRegistry.cxx

@@ -393,6 +393,10 @@ ModelRegistry::readImage(const string& fileName,
                         isEffect = true;
 //                        can_compress = false;
                     }
+                    else if (sgoptC && !transparent && sgoptC->getLoadOriginHint() == SGReaderWriterOptions::LoadOriginHint::ORIGIN_CANVAS) {
+                        SG_LOG(SG_IO, SG_INFO, "From Canvas " + absFileName + " will generate mipmap only");
+                        can_compress = false;
+                    }
                     if (can_compress)
                     {
                         std::string pot_message;

simgear/scene/model/animation.cxx

@@ -1135,16 +1135,8 @@ void SpinAnimCallback::operator()(osg::Node* node, osg::NodeVisitor* nv)
         double intPart;
         double rot = modf(rotation, &intPart);
         double angle = rot * 2.0 * osg::PI;
-        const SGVec3d& sgcenter = transform->getCenter();
-        const SGVec3d& sgaxis = transform->getAxis();
-        Matrixd mat = Matrixd::translate(-sgcenter[0], -sgcenter[1], -sgcenter[2])
-            * Matrixd::rotate(angle, sgaxis[0], sgaxis[1], sgaxis[2])
-            * Matrixd::translate(sgcenter[0], sgcenter[1], sgcenter[2])
-            * *cv->getModelViewMatrix();
-        ref_ptr<RefMatrix> refmat = new RefMatrix(mat);
-        cv->pushModelViewMatrix(refmat.get(), transform->getReferenceFrame());
+        transform->setAngleRad(angle);
         traverse(transform, nv);
-        cv->popModelViewMatrix();
     } else {
         traverse(transform, nv);
     }

simgear/scene/tgdb/ReaderWriterSPT.cxx

@@ -294,7 +294,7 @@ ReaderWriterSPT::createTree(const BucketBox& bucketBox, const LocalOptions& opti
 osg::ref_ptr<osg::Node>
 ReaderWriterSPT::createPagedLOD(const BucketBox& bucketBox, const LocalOptions& options) const
 {
-    osg::PagedLOD* pagedLOD = new osg::PagedLOD;
+    osg::ref_ptr<osg::PagedLOD> pagedLOD = new osg::PagedLOD;
 
     pagedLOD->setCenterMode(osg::PagedLOD::USER_DEFINED_CENTER);
     SGSpheref sphere = bucketBox.getBoundingSphere();

simgear/scene/tgdb/ReaderWriterSTG.cxx

@@ -212,7 +212,8 @@ struct ReaderWriterSTG::_ModelBin {
             STGObjectsQuadtree quadtree((GetModelLODCoord()), (AddModelLOD()));
             quadtree.buildQuadTree(_objectStaticList.begin(), _objectStaticList.end());
             osg::ref_ptr<osg::Group> group = quadtree.getRoot();
-            group->setName("STG-group-A");
+            string group_name = string("STG-group-A ").append(_bucket.gen_index_str());
+            group->setName(group_name);
             group->setDataVariance(osg::Object::STATIC);
 
             simgear::AirportSignBuilder signBuilder(_options->getMaterialLib(), _bucket.get_center());
@@ -586,10 +587,12 @@ struct ReaderWriterSTG::_ModelBin {
     {
         osg::ref_ptr<SGReaderWriterOptions> options;
         options = SGReaderWriterOptions::copyOrCreate(opt);
+        float pagedLODExpiry = atoi(options->getPluginStringData("SimGear::PAGED_LOD_EXPIRY").c_str());
 
         osg::ref_ptr<osg::Group> terrainGroup = new osg::Group;
         terrainGroup->setDataVariance(osg::Object::STATIC);
-        terrainGroup->setName("terrain");
+        std::string terrain_name = string("terrain ").append(bucket.gen_index_str());
+        terrainGroup->setName(terrain_name);
 
         if (_foundBase) {
             for (auto stgObject : _objectList) {
@@ -637,11 +640,13 @@ struct ReaderWriterSTG::_ModelBin {
         } else {
             osg::PagedLOD* pagedLOD = new osg::PagedLOD;
             pagedLOD->setCenterMode(osg::PagedLOD::USE_BOUNDING_SPHERE_CENTER);
-            pagedLOD->setName("pagedObjectLOD");
+            std::string name = string("pagedObjectLOD ").append(bucket.gen_index_str());
+            pagedLOD->setName(name);
 
             // This should be visible in any case.
             // If this is replaced by some lower level of detail, the parent LOD node handles this.
             pagedLOD->addChild(terrainGroup, 0, std::numeric_limits<float>::max());
+            pagedLOD->setMinimumExpiryTime(0, pagedLODExpiry);
 
             // we just need to know about the read file callback that itself holds the data
             osg::ref_ptr<DelayLoadReadFileCallback> readFileCallback = new DelayLoadReadFileCallback;
@@ -658,10 +663,11 @@ struct ReaderWriterSTG::_ModelBin {
 
             // Objects may end up displayed up to 2x the object range.
             pagedLOD->setRange(pagedLOD->getNumChildren(), 0, 2.0 * _object_range_rough);
+            pagedLOD->setMinimumExpiryTime(pagedLOD->getNumChildren(), pagedLODExpiry);
             pagedLOD->setRadius(SG_TILE_RADIUS);
-            SG_LOG( SG_TERRAIN, SG_DEBUG, "Tile PagedLOD Center: " << pagedLOD->getCenter().x() << "," << pagedLOD->getCenter().y() << "," << pagedLOD->getCenter().z() );
-            SG_LOG( SG_TERRAIN, SG_DEBUG, "Tile PagedLOD Range: " << (2.0 * _object_range_rough));
-            SG_LOG( SG_TERRAIN, SG_DEBUG, "Tile PagedLOD Radius: " << SG_TILE_RADIUS);
+            SG_LOG( SG_TERRAIN, SG_DEBUG, "Tile " << bucket.gen_index_str() << " PagedLOD Center: " << pagedLOD->getCenter().x() << "," << pagedLOD->getCenter().y() << "," << pagedLOD->getCenter().z() );
+            SG_LOG( SG_TERRAIN, SG_DEBUG, "Tile " << bucket.gen_index_str() << " PagedLOD Range: " << (2.0 * _object_range_rough));
+            SG_LOG( SG_TERRAIN, SG_DEBUG, "Tile " << bucket.gen_index_str() << " PagedLOD Radius: " << SG_TILE_RADIUS);
             return pagedLOD;
         }
     }

simgear/scene/tgdb/SGBuildingBin.cxx

@@ -441,6 +441,10 @@ typedef QuadTreeBuilder<LOD*, SGBuildingBin::BuildingInstance, MakeBuildingLeaf,
       if (hash_pos != std::string::npos)
           line.resize(hash_pos);
 
+      if (line.empty()) {
+          continue; // skip blank lines
+      }
+
       // and process further
       std::stringstream in(line);
 

simgear/scene/tgdb/SGOceanTile.cxx

@@ -41,6 +41,7 @@
 #include <simgear/scene/material/EffectGeode.hxx>
 #include <simgear/scene/material/mat.hxx>
 #include <simgear/scene/material/matlib.hxx>
+#include <simgear/scene/model/BoundingVolumeBuildVisitor.hxx>
 #include <simgear/scene/util/OsgMath.hxx>
 #include <simgear/scene/util/VectorArrayAdapter.hxx>
 #include <simgear/scene/util/SGNodeMasks.hxx>
@@ -340,5 +341,10 @@ osg::Node* SGOceanTile(const SGBucket& b, SGMaterialLib *matlib, int latPoints,
     transform->addChild(geode);
     transform->setNodeMask( ~(simgear::CASTSHADOW_BIT | simgear::MODELLIGHT_BIT) );
 
+    // Create a BVH at this point.  This is normally provided by the file loader, but as we create the 
+    // geometry programmatically, no file loader is involved.
+    BoundingVolumeBuildVisitor bvhBuilder(false);
+    transform->accept(bvhBuilder);
+    
     return transform;
 }

simgear/scene/tsync/terrasync.cxx

@@ -334,6 +334,10 @@ public:
     void runInternal();
     void updateSyncSlot(SyncSlot& slot);
 
+    void beginSyncAirports(SyncSlot& slot);
+    void beginSyncTile(SyncSlot& slot);
+    void beginNormalSync(SyncSlot& slot);
+
     void drainWaitingTiles();
 
     // commond helpers between both internal and external models
@@ -547,6 +551,7 @@ void SGTerraSync::WorkerThread::run()
 void SGTerraSync::WorkerThread::updateSyncSlot(SyncSlot &slot)
 {
     if (slot.repository.get()) {
+        slot.repository->process();
         if (slot.repository->isDoingSync()) {
 #if 1
             if (slot.stamp.elapsedMSec() > (int)slot.nextWarnTimeout) {
@@ -567,6 +572,15 @@ void SGTerraSync::WorkerThread::updateSyncSlot(SyncSlot &slot)
             notFound(slot.currentItem);
         } else if (res != HTTPRepository::REPO_NO_ERROR) {
             fail(slot.currentItem);
+
+            // in case the Airports_archive download fails, create the
+            // directory, so that next sync, we do a manual sync
+            if ((slot.currentItem._type == SyncItem::AirportData) && slot.isNewDirectory) {
+                SG_LOG(SG_TERRASYNC, SG_ALERT, "Failed to download Airports_archive, will download discrete files next time");
+                simgear::Dir d(_local_dir + "/Airports");
+                d.create(0755);
+                _completedTiles.erase(slot.currentItem._dir);
+            }
         } else {
             updated(slot.currentItem, slot.isNewDirectory);
             SG_LOG(SG_TERRASYNC, SG_DEBUG, "sync of " << slot.repository->baseUrl() << " finished ("
@@ -588,47 +602,14 @@ void SGTerraSync::WorkerThread::updateSyncSlot(SyncSlot &slot)
         SGPath path(_local_dir);
         path.append(slot.currentItem._dir);
         slot.isNewDirectory = !path.exists();
-        if (slot.isNewDirectory) {
-            int rc = path.create_dir( 0755 );
-            if (rc) {
-                SG_LOG(SG_TERRASYNC,SG_ALERT,
-                       "Cannot create directory '" << path << "', return code = " << rc );
-                fail(slot.currentItem);
-                return;
-            }
-        } // of creating directory step
-
-        // optimise initial Airport download
-        if (slot.isNewDirectory &&
-            (slot.currentItem._type == SyncItem::AirportData)) {
-          SG_LOG(SG_TERRASYNC, SG_INFO, "doing Airports download via tarball");
-
-          // we want to sync the 'root' TerraSync dir, but not all of it, just
-          // the Airports_archive.tar.gz file so we use our TerraSync local root
-          // as the path (since the archive will add Airports/)
-          slot.repository.reset(new HTTPRepository(_local_dir, &_http));
-          slot.repository->setBaseUrl(_httpServer + "/");
-
-          // filter callback to *only* sync the Airport_archive tarball,
-          // and ensure no other contents are touched
-          auto f = [](const HTTPRepository::SyncItem &item) {
-            if (!item.directory.empty())
-              return false;
-            return (item.filename.find("Airports_archive.") == 0);
-          };
-
-          slot.repository->setFilter(f);
+        const auto type = slot.currentItem._type;
 
+        if (type == SyncItem::AirportData) {
+            beginSyncAirports(slot);
+        } else if (type == SyncItem::Tile) {
+            beginSyncTile(slot);
         } else {
-          slot.repository.reset(new HTTPRepository(path, &_http));
-          slot.repository->setBaseUrl(_httpServer + "/" +
-                                      slot.currentItem._dir);
-        }
-
-        if (_installRoot.exists()) {
-            SGPath p = _installRoot;
-            p.append(slot.currentItem._dir);
-            slot.repository->setInstalledCopyPath(p);
+            beginNormalSync(slot);
         }
 
         try {
@@ -651,6 +632,96 @@ void SGTerraSync::WorkerThread::updateSyncSlot(SyncSlot &slot)
     }
 }
 
+void SGTerraSync::WorkerThread::beginSyncAirports(SyncSlot& slot)
+{
+    if (!slot.isNewDirectory) {
+        beginNormalSync(slot);
+        return;
+    }
+
+    SG_LOG(SG_TERRASYNC, SG_INFO, "doing Airports download via tarball");
+
+    // we want to sync the 'root' TerraSync dir, but not all of it, just
+    // the Airports_archive.tar.gz file so we use our TerraSync local root
+    // as the path (since the archive will add Airports/)
+    slot.repository.reset(new HTTPRepository(_local_dir, &_http));
+    slot.repository->setBaseUrl(_httpServer);
+
+    // filter callback to *only* sync the Airport_archive tarball,
+    // and ensure no other contents are touched
+    auto f = [](const HTTPRepository::SyncItem& item) {
+        if (!item.directory.empty())
+            return false;
+        return (item.filename.find("Airports_archive.") == 0);
+    };
+
+    slot.repository->setFilter(f);
+}
+
+void SGTerraSync::WorkerThread::beginSyncTile(SyncSlot& slot)
+{
+    // avoid 404 requests by doing a sync which excludes all paths
+    // except our tile path. In the case of a missing 1x1 tile, we will
+    // stop becuase all directories are filtered out, which is what we want
+
+    auto comps = strutils::split(slot.currentItem._dir, "/");
+    if (comps.size() != 3) {
+        SG_LOG(SG_TERRASYNC, SG_ALERT, "Bad tile path:" << slot.currentItem._dir);
+        beginNormalSync(slot);
+        return;
+    }
+
+    const auto tileCategory = comps.front();
+    const auto tenByTenDir = comps.at(1);
+    const auto oneByOneDir = comps.at(2);
+
+    const auto path = SGPath::fromUtf8(_local_dir) / tileCategory;
+    slot.repository.reset(new HTTPRepository(path, &_http));
+    slot.repository->setBaseUrl(_httpServer + "/" + tileCategory);
+
+    if (_installRoot.exists()) {
+      SGPath p = _installRoot / tileCategory;
+      slot.repository->setInstalledCopyPath(p);
+    }
+
+    const auto dirPrefix = tenByTenDir + "/" + oneByOneDir;
+
+    // filter callback to *only* sync the 1x1 dir we want, if it exists
+    // if doesn't, we'll simply stop, which is what we want
+    auto f = [tenByTenDir, oneByOneDir, dirPrefix](const HTTPRepository::SyncItem& item) {
+        // only allow the specific 10x10 and 1x1 dirs we want
+        if (item.directory.empty()) {
+            return item.filename == tenByTenDir;
+        } else if (item.directory == tenByTenDir) {
+            return item.filename == oneByOneDir;
+        }
+
+        // allow arbitrary children below dirPrefix, including sub-dirs
+        if (item.directory.find(dirPrefix) == 0) {
+            return true;
+        }
+
+        SG_LOG(SG_TERRASYNC, SG_ALERT, "Tile sync: saw weird path:" << item.directory << " file " << item.filename);
+        return false;
+    };
+
+    slot.repository->setFilter(f);
+}
+
+void SGTerraSync::WorkerThread::beginNormalSync(SyncSlot& slot)
+{
+    SGPath path(_local_dir);
+    path.append(slot.currentItem._dir);
+    slot.repository.reset(new HTTPRepository(path, &_http));
+    slot.repository->setBaseUrl(_httpServer + "/" + slot.currentItem._dir);
+
+    if (_installRoot.exists()) {
+      SGPath p = _installRoot;
+      p.append(slot.currentItem._dir);
+      slot.repository->setInstalledCopyPath(p);
+    }
+}
+
 void SGTerraSync::WorkerThread::runInternal()
 {
     while (!_stop) {

simgear/scene/util/SGReaderWriterOptions.hxx

@@ -46,6 +46,7 @@ public:
         ORIGIN_EFFECTS,
         ORIGIN_EFFECTS_NORMALIZED,
         ORIGIN_SPLASH_SCREEN,
+        ORIGIN_CANVAS,
     };
 
     //SGReaderWriterOptions* cloneOptions(const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY) const { return static_cast<SGReaderWriterOptions*>(clone(copyop)); }

simgear/structure/SGAction.cxx

@@ -0,0 +1,86 @@
+
+
+#if 0
+
+set bindings for action seperate from defintion ?
+    - in XML, especially aircraft XML
+
+define actions from command / Nasal
+add behaviours from Nasal 
+
+define keymapping
+    - manager of keybindings defined against actions?
+    - for a toggle or enum, define behaviour
+        - each key repeat cycles
+        - alternate key to go the other way (G/shift-G)
+
+release bindings for momentary actions:
+    button up / key-up
+
+send activate, release
+
+    send deactivate, release for 'alternate' action
+
+#endif
+
+
+void SGAction::setValueExpression()
+{
+    // watch all the properties
+}
+
+void SGAction::setValueCondition()
+{
+    // 
+}
+
+void SGAction::updateProperties()
+{
+    //
+    _node->setBoolValue("enabled", isEnabled());
+    switch (_type) {
+    case Momentary:
+    case Toggle:
+        _node->setBoolValue("value", getValue());
+        break;
+
+    case Enumerated: 
+        if (!_valueEnumeration.empty()) {
+            // map to the string value
+            _node->setStringValue("value", _valueEnumeration.at(getValue()));
+        } else {
+            // set as an integer
+            _node->setIntValue("value", getValue());
+        }
+    }
+
+    // set description
+}
+
+bool SGAction::isEnabled()
+{
+    if (_enableCondition) {
+
+    } else {
+        return _enabled;
+    }
+
+    updateProperties();
+}
+
+int SGAction::getValue()
+{
+    if (type == Enumerated) {
+        if (_valueExpression) {
+            // invoke it
+        }
+    } else {
+        if (_valueCondition) {
+            return _valueCondition.test();
+        }
+    }
+
+    return _value;
+}
+
+// commands enable-action, disable-action

simgear/structure/StateMachine.cxx

@@ -441,7 +441,7 @@ void StateMachine::initFromPlist(SGPropertyNode* desc, SGPropertyNode* root)
         std::string nm = stateDesc->getStringValue("name");
 
         if (nm.empty()) {
-          SG_LOG(SG_GENERAL, SG_ALERT, "No name found for state in branch " << path);
+          SG_LOG(SG_GENERAL, SG_DEV_ALERT, "No name found for state in branch " << path);
           throw sg_exception("No name element in state");
         }
 
@@ -464,8 +464,8 @@ void StateMachine::initFromPlist(SGPropertyNode* desc, SGPropertyNode* root)
         std::string target_id = tDesc->getStringValue("target");
 
         if (nm.empty()) {
-          SG_LOG(SG_GENERAL, SG_ALERT, "No name found for transition in branch " << path);
-          throw sg_exception("No name element in transition");
+          SG_LOG(SG_GENERAL, SG_DEV_WARN, "No name found for transition in branch " << path);
+          nm = "transition-to-" + target_id;
         }
 
         if (target_id.empty()) {

simgear/structure/subsystem_mgr.cxx

@@ -30,9 +30,10 @@
 #include "subsystem_mgr.hxx"
 #include "commands.hxx"
 
-#include <simgear/props/props.hxx>
-#include <simgear/math/SGMath.hxx>
 #include "SGSmplstat.hxx"
+#include <simgear/debug/ErrorReportingCallback.hxx>
+#include <simgear/math/SGMath.hxx>
+#include <simgear/props/props.hxx>
 
 const int SG_MAX_SUBSYSTEM_EXCEPTIONS = 4;
 const char SUBSYSTEM_NAME_SEPARATOR = '.';
@@ -828,8 +829,18 @@ SGSubsystemGroup::Member::update (double delta_time_sec)
       if (++exceptionCount > SG_MAX_SUBSYSTEM_EXCEPTIONS) {
         SG_LOG(SG_GENERAL, SG_ALERT, "(exceptionCount=" << exceptionCount <<
           ", suspending)");
+        simgear::reportError("suspending subsystem after too many errors:" + name);
         subsystem->suspend();
       }
+    } catch (std::bad_alloc& ba) {
+        // attempting to track down source of these on Sentry.io
+        SG_LOG(SG_GENERAL, SG_ALERT, "caught bad_alloc processing subsystem:" << name);
+        simgear::reportError("caught bad_alloc processing subsystem:" + name);
+
+        if (++exceptionCount > SG_MAX_SUBSYSTEM_EXCEPTIONS) {
+            SG_LOG(SG_GENERAL, SG_ALERT, "(exceptionCount=" << exceptionCount << ", suspending)");
+            subsystem->suspend();
+        }
     }
 }