From 18d5a9159f9c66336c40bf91b77dfe3ebe3af31f Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Sun, 21 Jan 2018 12:09:49 +0000
Subject: [PATCH] Restructured the system() fallback to be usable for C and C++

---
 include/osg/os_utils                         | 37 ++++++++++----------
 src/osg/CMakeLists.txt                       |  1 +
 src/osg/os_utils.cpp                         | 28 +++++++++++++++
 src/osgPlugins/lua/lua-5.2.3/src/loslib.c    |  8 ++---
 src/osgPlugins/osgtgz/ReaderWriterOSGTGZ.cpp |  4 +--
 src/osgPlugins/tgz/ReaderWriterTGZ.cpp       |  4 +--
 src/osgPresentation/KeyEventHandler.cpp      |  2 +-
 src/osgPresentation/PickEventHandler.cpp     |  2 +-
 src/osgPresentation/SlideEventHandler.cpp    |  4 +--
 src/osgPresentation/SlideShowConstructor.cpp |  2 +-
 10 files changed, 59 insertions(+), 33 deletions(-)
 create mode 100644 src/osg/os_utils.cpp

diff --git a/include/osg/os_utils b/include/osg/os_utils
index 2caf78a9f..b46073f5b 100644
--- a/include/osg/os_utils
+++ b/include/osg/os_utils
@@ -11,33 +11,32 @@
  * OpenSceneGraph Public License for more details.
 */
 
-#ifndef OSG_osg_utils
-#define OSG_osg_utils 1
+#ifndef OSG_os_utils
+#define OSG_os_utils 1
 
-#include <osg/Config>
+#include <osg/Export>
 
-#if defined(OSG_SYSTEM_SUPPORTED) || defined(OSG_ENVVAR_SUPPORTED)
-    #include <stdlib.h>
+#ifdef __cplusplus
+extern "C" {
 #endif
 
-#ifdef OSG_ENVVAR_SUPPORTED
+/** Cross platform version of C system() function. */
+extern OSG_EXPORT int osg_system(const char* str);
+
+#ifdef __cplusplus
+}
+#endif
+
+
+#ifdef __cplusplus
+
+#if defined(OSG_ENVVAR_SUPPORTED)
+    #include <stdlib.h>
     #include <sstream>
 #endif
 
 namespace osg {
 
-#ifdef OSG_SYSTEM_SUPPORTED
-inline int system(const char* command)
-{
-    return ::system(command);
-}
-#else
-inline int system(const char* command)
-{
-    OSG_WARN<<"system("<<command<<") not supported on this platform."<<std::endl;
-    return 0;
-}
-#endif
 
 inline unsigned int getClampedLength(const char* str, unsigned int maxNumChars=4096)
 {
@@ -131,4 +130,6 @@ inline bool getEnvVar(const char* name, T1& value1, T2& value2, T3& value3, T4&
 
 }
 
+#endif // _cplusplus
+
 # endif
diff --git a/src/osg/CMakeLists.txt b/src/osg/CMakeLists.txt
index a0e19c622..96a072b59 100644
--- a/src/osg/CMakeLists.txt
+++ b/src/osg/CMakeLists.txt
@@ -240,6 +240,7 @@ SET(TARGET_H
 #    ${OPENSCENEGRAPH_USER_DEFINED_DYNAMIC_OR_STATIC}
 #    ${LIB_PUBLIC_HEADERS}
 SET(TARGET_SRC
+    os_utils.cpp
     AlphaFunc.cpp
     AnimationPath.cpp
     ApplicationUsage.cpp
diff --git a/src/osg/os_utils.cpp b/src/osg/os_utils.cpp
new file mode 100644
index 000000000..84613ad81
--- /dev/null
+++ b/src/osg/os_utils.cpp
@@ -0,0 +1,28 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 2018 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * 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
+ * OpenSceneGraph Public License for more details.
+*/
+
+#include <osg/os_utils>
+
+extern "C" {
+
+int osg_system(const char* command)
+{
+#ifdef OSG_SYSTEM_SUPPORTED
+    return system(command);
+#else
+    printf("osgSystem(%s) not supported.\n", command);
+#endif
+}
+
+}
+
diff --git a/src/osgPlugins/lua/lua-5.2.3/src/loslib.c b/src/osgPlugins/lua/lua-5.2.3/src/loslib.c
index 5a7904a6b..6fb877829 100644
--- a/src/osgPlugins/lua/lua-5.2.3/src/loslib.c
+++ b/src/osgPlugins/lua/lua-5.2.3/src/loslib.c
@@ -19,7 +19,7 @@
 #include "lauxlib.h"
 #include "lualib.h"
 
-#include <osg/Config>
+#include <osg/os_utils>
 
 /*
 ** list of valid conversion specifiers for the 'strftime' function
@@ -80,18 +80,14 @@
 
 static int os_execute (lua_State *L) {
 
-#if defined(OSG_SYSTEM_SUPPORTED)
   const char *cmd = luaL_optstring(L, 1, NULL);
-  int stat = system(cmd);
+  int stat = osg_system(cmd);
   if (cmd != NULL)
     return luaL_execresult(L, stat);
   else {
     lua_pushboolean(L, stat);  /* true if there is a shell */
     return 1;
   }
-#else
-    return 0;
-#endif
 }
 
 
diff --git a/src/osgPlugins/osgtgz/ReaderWriterOSGTGZ.cpp b/src/osgPlugins/osgtgz/ReaderWriterOSGTGZ.cpp
index 788875a22..9fa7bc5e3 100644
--- a/src/osgPlugins/osgtgz/ReaderWriterOSGTGZ.cpp
+++ b/src/osgPlugins/osgtgz/ReaderWriterOSGTGZ.cpp
@@ -78,7 +78,7 @@ class sgReaderWriterOSGTGZ : public osgDB::ReaderWriter
             mkdir( dirname, 0700 );
         #endif
 
-            if (osg::system( command ) ) {
+            if (osg_system( command ) ) {
                 return ReadResult::FILE_NOT_HANDLED;
             }
 
@@ -108,7 +108,7 @@ class sgReaderWriterOSGTGZ : public osgDB::ReaderWriter
 
             sprintf( command, "rm -rf %s", dirname );
         #endif
-            if (osg::system( command ) ) {
+            if (osg_system( command ) ) {
                 return ReadResult::FILE_NOT_HANDLED;
             }
 
diff --git a/src/osgPlugins/tgz/ReaderWriterTGZ.cpp b/src/osgPlugins/tgz/ReaderWriterTGZ.cpp
index d9345bd19..6f1b7f81f 100644
--- a/src/osgPlugins/tgz/ReaderWriterTGZ.cpp
+++ b/src/osgPlugins/tgz/ReaderWriterTGZ.cpp
@@ -95,7 +95,7 @@ class ReaderWriterTGZ : public osgDB::ReaderWriter
 
             OSG_NOTICE<<"Running command '"<<command<<"'"<<std::endl;
 
-            int result = osg::system( command );
+            int result = osg_system( command );
             if (result!=0) return ReadResult::ERROR_IN_READING_FILE;
 
 
@@ -138,7 +138,7 @@ class ReaderWriterTGZ : public osgDB::ReaderWriter
         #endif
             OSG_NOTICE<<"Running command '"<<command<<"'"<<std::endl;
 
-            result = osg::system( command );
+            result = osg_system( command );
             if (result!=0) return ReadResult::ERROR_IN_READING_FILE;
 
             if( grp->getNumChildren() == 0 )
diff --git a/src/osgPresentation/KeyEventHandler.cpp b/src/osgPresentation/KeyEventHandler.cpp
index 1b7e7dc6d..84f3c85de 100644
--- a/src/osgPresentation/KeyEventHandler.cpp
+++ b/src/osgPresentation/KeyEventHandler.cpp
@@ -120,7 +120,7 @@ void KeyEventHandler::doOperation()
 
             bool commandRunsInBackground = (_command.find("&")!=std::string::npos);
 
-            int result = osg::system(_command.c_str());
+            int result = osg_system(_command.c_str());
 
             OSG_INFO<<"system("<<_command<<") result "<<result<<std::endl;
 
diff --git a/src/osgPresentation/PickEventHandler.cpp b/src/osgPresentation/PickEventHandler.cpp
index abbc6c034..16b3ad4fe 100644
--- a/src/osgPresentation/PickEventHandler.cpp
+++ b/src/osgPresentation/PickEventHandler.cpp
@@ -231,7 +231,7 @@ void PickEventHandler::doOperation()
 
             bool commandRunsInBackground = (_command.find("&")!=std::string::npos);
 
-            int result = osg::system(_command.c_str());
+            int result = osg_system(_command.c_str());
 
             OSG_INFO<<"system("<<_command<<") result "<<result<<std::endl;
 
diff --git a/src/osgPresentation/SlideEventHandler.cpp b/src/osgPresentation/SlideEventHandler.cpp
index 96013b43f..0bfa3078c 100644
--- a/src/osgPresentation/SlideEventHandler.cpp
+++ b/src/osgPresentation/SlideEventHandler.cpp
@@ -421,7 +421,7 @@ struct LayerAttributesOperator : public ObjectOperator
                 OSG_NOTICE<<"Run "<<itr->c_str()<<std::endl;
                 osg::Timer_t startTick = osg::Timer::instance()->tick();
 
-                int result = osg::system(itr->c_str());
+                int result = osg_system(itr->c_str());
 
                 OSG_INFO<<"system("<<*itr<<") result "<<result<<std::endl;
 
@@ -1258,7 +1258,7 @@ bool SlideEventHandler::handle(const osgGA::GUIEventAdapter& ea,osgGA::GUIAction
                     std::stringstream command;
                     command<<editor<<" "<<filename<<" &"<<std::endl;
 
-                    int result = osg::system(command.str().c_str());
+                    int result = osg_system(command.str().c_str());
 
                     OSG_INFO<<"system("<<command.str()<<") result "<<result<<std::endl;
 
diff --git a/src/osgPresentation/SlideShowConstructor.cpp b/src/osgPresentation/SlideShowConstructor.cpp
index ad5d9ee8c..d4ee8b266 100644
--- a/src/osgPresentation/SlideShowConstructor.cpp
+++ b/src/osgPresentation/SlideShowConstructor.cpp
@@ -1750,7 +1750,7 @@ void SlideShowConstructor::addGraph(const std::string& contents, const PositionD
 
     std::stringstream command;
     command<<"dot -Tsvg "<<dotFileName<<" -o "<<tmpSvgFileName;
-    int result = osg::system(command.str().c_str());
+    int result = osg_system(command.str().c_str());
     if (result==0)
     {
         osg::ref_ptr<osgDB::Options> previousOptions = _options;