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simgear/simgear/structure/subsystem_mgr.hxx
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2018-04-25 11:41:40 +01:00

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// Written by David Megginson, started 2000-12
//
// Copyright (C) 2000 David Megginson, david@megginson.com
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program 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
// 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.
//
// $Id$
#ifndef __SUBSYSTEM_MGR_HXX
#define __SUBSYSTEM_MGR_HXX 1
#include <simgear/compiler.h>
#include <string>
#include <map>
#include <vector>
#include <functional>
#include <simgear/timing/timestamp.hxx>
#include <simgear/structure/SGSharedPtr.hxx>
#include <simgear/misc/strutils.hxx>
class TimingInfo
{
private:
std::string eventName;
SGTimeStamp time;
public:
TimingInfo(const std::string& name, const SGTimeStamp &t) :
eventName(name), time(t)
{ }
const std::string& getName() const { return eventName; }
const SGTimeStamp& getTime() const { return time; }
};
// forward decls
class SampleStatistic;
class SGSubsystemGroup;
class SGSubsystemMgr;
typedef std::vector<TimingInfo> eventTimeVec;
typedef std::vector<TimingInfo>::iterator eventTimeVecIterator;
typedef void (*SGSubsystemTimingCb)(void* userData, const std::string& name, SampleStatistic* pStatistic);
/**
* Basic interface for all FlightGear subsystems.
*
* <p>This is an abstract interface that all FlightGear subsystems
* will eventually implement. It defines the basic operations for
* each subsystem: initialization, property binding and unbinding, and
* updating. Interfaces may define additional methods, but the
* preferred way of exchanging information with other subsystems is
* through the property tree.</p>
*
* <p>To publish information through a property, a subsystem should
* bind it to a variable or (if necessary) a getter/setter pair in the
* bind() method, and release the property in the unbind() method:</p>
*
* <pre>
* void MySubsystem::bind ()
* {
* fgTie("/controls/flight/elevator", &_elevator);
* fgSetArchivable("/controls/flight/elevator");
* }
*
* void MySubsystem::unbind ()
* {
* fgUntie("/controls/flight/elevator");
* }
* </pre>
*
* <p>To reference a property (possibly) from another subsystem, there
* are two alternatives. If the property will be referenced only
* infrequently (say, in the init() method), then the fgGet* methods
* declared in fg_props.hxx are the simplest:</p>
*
* <pre>
* void MySubsystem::init ()
* {
* _errorMargin = fgGetFloat("/display/error-margin-pct");
* }
* </pre>
*
* <p>On the other hand, if the property will be referenced frequently
* (say, in the update() method), then the hash-table lookup required
* by the fgGet* methods might be too expensive; instead, the
* subsystem should obtain a reference to the actual property node in
* its init() function and use that reference in the main loop:</p>
*
* <pre>
* void MySubsystem::init ()
* {
* _errorNode = fgGetNode("/display/error-margin-pct", true);
* }
*
* void MySubsystem::update (double delta_time_sec)
* {
* do_something(_errorNode.getFloatValue());
* }
* </pre>
*
* <p>The node returned will always be a pointer to SGPropertyNode,
* and the subsystem should <em>not</em> delete it in its destructor
* (the pointer belongs to the property tree, not the subsystem).</p>
*
* <p>The program may ask the subsystem to suspend or resume
* sim-time-dependent operations; by default, the suspend() and
* resume() methods set the protected variable <var>_suspended</var>,
* which the subsystem can reference in its update() method, but
* subsystems may also override the suspend() and resume() methods to
* take different actions.</p>
*/
class SGSubsystem : public SGReferenced
{
public:
/**
* Default constructor.
*/
SGSubsystem ();
/**
* Virtual destructor to ensure that subclass destructors are called.
*/
virtual ~SGSubsystem ();
/**
* Initialize the subsystem.
*
* <p>This method should set up the state of the subsystem, but
* should not bind any properties. Note that any dependencies on
* the state of other subsystems should be placed here rather than
* in the constructor, so that FlightGear can control the
* initialization order.</p>
*/
virtual void init ();
typedef enum
{
INIT_DONE, ///< subsystem is fully initialised
INIT_CONTINUE ///< init should be called again
} InitStatus;
virtual InitStatus incrementalInit ();
/**
* Initialize parts that depend on other subsystems having been initialized.
*
* <p>This method should set up all parts that depend on other
* subsystems. One example is the scripting/Nasal subsystem, which
* is initialized last. So, if a subsystem wants to execute Nasal
* code in subsystem-specific configuration files, it has to do that
* in its postinit() method.</p>
*/
virtual void postinit ();
/**
* Reinitialize the subsystem.
*
* <p>This method should cause the subsystem to reinitialize itself,
* and (normally) to reload any configuration files.</p>
*/
virtual void reinit ();
/**
* Shutdown the subsystem.
*
* <p>Release any state associated with subsystem. Shutdown happens in
* the reverse order to init(), so this is the correct place to do
* shutdown that depends on other subsystems.
* </p>
*/
virtual void shutdown ();
/**
* Acquire the subsystem's property bindings.
*
* <p>This method should bind all properties that the subsystem
* publishes. It will be invoked after init, but before any
* invocations of update.</p>
*/
virtual void bind ();
/**
* Release the subsystem's property bindings.
*
* <p>This method should release all properties that the subsystem
* publishes. It will be invoked by FlightGear (not the destructor)
* just before the subsystem is removed.</p>
*/
virtual void unbind ();
/**
* Update the subsystem.
*
* <p>FlightGear invokes this method every time the subsystem should
* update its state.</p>
*
* @param delta_time_sec The delta time, in seconds, since the last
* update. On first update, delta time will be 0.
*/
virtual void update (double delta_time_sec) = 0;
/**
* Suspend operation of this subsystem.
*
* <p>This method instructs the subsystem to suspend
* sim-time-dependent operations until asked to resume. The update
* method will still be invoked so that the subsystem can take any
* non-time-dependent actions, such as updating the display.</p>
*
* <p>It is not an error for the suspend method to be invoked when
* the subsystem is already suspended; the invocation should simply
* be ignored.</p>
*/
virtual void suspend ();
/**
* Suspend or resume operation of this subsystem.
*
* @param suspended true if the subsystem should be suspended, false
* otherwise.
*/
virtual void suspend (bool suspended);
/**
* Resume operation of this subsystem.
*
* <p>This method instructs the subsystem to resume
* sim-time-depended operations. It is not an error for the resume
* method to be invoked when the subsystem is not suspended; the
* invocation should simply be ignored.</p>
*/
virtual void resume ();
/**
* Test whether this subsystem is suspended.
*
* @return true if the subsystem is suspended, false if it is not.
*/
virtual bool is_suspended () const;
/**
* Trigger the callback to report timing information for all subsystems.
*/
void reportTiming(void);
/**
* Place time stamps at strategic points in the execution of subsystems
* update() member functions. Predominantly for debugging purposes.
*/
void stamp(const std::string& name);
std::string name() const
{ return _name; }
virtual bool is_group() const
{ return false; }
virtual SGSubsystemMgr* get_manager() const;
/// get the parent group of this subsystem
SGSubsystemGroup* get_group() const;
enum class State {
ADD,
BIND,
INIT,
POSTINIT,
REINIT,
SUSPEND,
RESUME,
UNBIND,
SHUTDOWN,
REMOVE
};
/**
* debug helper, print a state as a string
*/
static std::string nameForState(State s);
protected:
friend class SGSubsystemMgr;
friend class SGSubsystemGroup;
void set_name(const std::string& n);
void set_group(SGSubsystemGroup* group);
std::string _name;
bool _suspended = false;
eventTimeVec timingInfo;
static SGSubsystemTimingCb reportTimingCb;
static void* reportTimingUserData;
private:
SGSubsystemGroup* _group = nullptr;
};
typedef SGSharedPtr<SGSubsystem> SGSubsystemRef;
/**
* A group of FlightGear subsystems.
*/
class SGSubsystemGroup : public SGSubsystem
{
public:
SGSubsystemGroup ();
virtual ~SGSubsystemGroup ();
void init() override;
InitStatus incrementalInit () override;
void postinit () override;
void reinit () override;
void shutdown () override;
void bind () override;
void unbind () override;
void update (double delta_time_sec) override;
void suspend () override;
void resume () override;
bool is_suspended () const override;
virtual void set_subsystem (const std::string &name,
SGSubsystem * subsystem,
double min_step_sec = 0);
void set_subsystem (SGSubsystem * subsystem, double min_step_sec = 0);
virtual SGSubsystem * get_subsystem (const std::string &name);
bool remove_subsystem (const std::string &name);
virtual bool has_subsystem (const std::string &name) const;
/**
* Remove all subsystems.
*/
virtual void clearSubsystems();
void reportTiming(void);
/**
*
*/
void set_fixed_update_time(double fixed_dt);
/**
* retrive list of member subsystem names
*/
string_list member_names() const;
template<class T>
T* get_subsystem()
{
return dynamic_cast<T*>(get_subsystem(T::subsystemName()));
}
bool is_group() const override
{ return true; }
SGSubsystemMgr* get_manager() const override;
private:
void forEach(std::function<void(SGSubsystem*)> f);
void reverseForEach(std::function<void(SGSubsystem*)> f);
void notifyWillChange(SGSubsystem* sub, SGSubsystem::State s);
void notifyDidChange(SGSubsystem* sub, SGSubsystem::State s);
friend class SGSubsystemMgr;
void set_manager(SGSubsystemMgr* manager);
class Member;
Member* get_member (const std::string &name, bool create = false);
using MemberVec = std::vector<Member*>;
MemberVec _members;
double _fixedUpdateTime;
double _updateTimeRemainder;
/// index of the member we are currently init-ing
int _initPosition;
/// back-pointer to the manager, for the root groups. (sub-groups
/// will have this as null, and chain via their parent)
SGSubsystemMgr* _manager = nullptr;
};
typedef SGSharedPtr<SGSubsystemGroup> SGSubsystemGroupRef;
/**
* Manage subsystems for FlightGear.
*
* This top-level subsystem will eventually manage all of the
* subsystems in FlightGear: it broadcasts its life-cycle events
* (init, bind, etc.) to all of the subsystems it manages. Subsystems
* are grouped to guarantee order of initialization and execution --
* currently, the only two groups are INIT and GENERAL, but others
* will appear in the future.
*
* All subsystems are named as well as grouped, and subsystems can be
* looked up by name and cast to the appropriate subtype when another
* subsystem needs to invoke specialized methods.
*
* The subsystem manager owns the pointers to all the subsystems in
* it.
*/
class SGSubsystemMgr : public SGSubsystem
{
public:
/**
* Types of subsystem groups.
*/
enum GroupType {
INVALID = -1,
INIT = 0,
GENERAL,
FDM, ///< flight model, autopilot, instruments that run coupled
POST_FDM, ///< certain subsystems depend on FDM data
DISPLAY, ///< view, camera, rendering updates
SOUND/*I want to be last!*/, ///< needs to run AFTER display, to allow concurrent GPU/sound processing
MAX_GROUPS
};
SGSubsystemMgr ();
virtual ~SGSubsystemMgr ();
void init () override;
InitStatus incrementalInit () override;
void postinit () override;
void reinit () override;
void shutdown () override;
void bind () override;
void unbind () override;
void update (double delta_time_sec) override;
void suspend () override;
void resume () override;
bool is_suspended () const override;
virtual void add (const char * name,
SGSubsystem * subsystem,
GroupType group = GENERAL,
double min_time_sec = 0);
/**
* remove a subsystem, and return true on success
* returns false if the subsystem was not found
*/
bool remove(const char* name);
virtual SGSubsystemGroup * get_group (GroupType group);
SGSubsystem* get_subsystem(const std::string &name) const;
SGSubsystem* get_subsystem(const std::string &name, const std::string& instanceName) const;
void reportTiming();
void setReportTimingCb(void* userData,SGSubsystemTimingCb cb) {reportTimingCb = cb;reportTimingUserData = userData;}
template<class T>
T* get_subsystem() const
{
return dynamic_cast<T*>(get_subsystem(T::subsystemName()));
}
// instanced overloads, for both raw char* and std::string
// these concatenate the subsystem type name with the instance name
template<class T>
T* get_subsystem(const char* instanceName) const
{
return dynamic_cast<T*>(get_subsystem(T::subsystemName(), instanceName));
}
template<class T>
T* get_subsystem(const std::string& instanceName) const
{
return dynamic_cast<T*>(get_subsystem(T::subsystemName(), instanceName));
}
struct Dependency {
enum Type {
HARD,
SOFT,
PROPERTY
};
std::string name;
Type type;
};
using DependencyVec = std::vector<SGSubsystemMgr::Dependency>;
using SubsystemFactoryFunctor = std::function<SGSubsystemRef()>;
/**
* @brief register a subsytem with the manager
*
*/
static void registerSubsystem(const std::string& name,
SubsystemFactoryFunctor f,
GroupType group,
bool isInstanced = false,
double updateInterval = 0.0,
std::initializer_list<Dependency> deps = {});
template<class T>
class Registrant
{
public:
Registrant(GroupType group = GENERAL, double updateInterval = 0.0,
std::initializer_list<Dependency> deps = {})
{
SubsystemFactoryFunctor factory = [](){ return new T; };
SGSubsystemMgr::registerSubsystem(T::subsystemName(),
factory, group,
false, updateInterval,
deps);
}
// could implement a dtor to unregister but not needed at the moment
};
template<class T>
class InstancedRegistrant
{
public:
InstancedRegistrant(GroupType group = GENERAL,
double updateInterval = 0.0,
std::initializer_list<Dependency> deps = {})
{
SubsystemFactoryFunctor factory = [](){ return new T; };
SGSubsystemMgr::registerSubsystem(T::subsystemName(),
factory, group,
true, updateInterval,
deps);
}
// could implement a dtor to unregister but not needed at the moment
};
/**
* @brief templated add function, subsystem is deduced automatically
*
*/
template <class T>
SGSharedPtr<T> add(GroupType customGroup = INVALID, double customInterval = 0.0)
{
auto ref = create(T::subsystemName());
const GroupType group = (customGroup == INVALID) ?
defaultGroupFor(T::subsystemName()) : customGroup;
const double interval = (customInterval == 0.0) ?
defaultUpdateIntervalFor(T::subsystemName()) : customInterval;
add(ref->name().c_str(), ref.ptr(), group, interval);
return dynamic_cast<T*>(ref.ptr());
}
/**
* @brief templated creation function, only makes the instance but
* doesn't add to the manager or group heirarchy
*/
template <class T>
SGSharedPtr<T> create()
{
auto ref = create(T::subsystemName());
return dynamic_cast<T*>(ref.ptr());
}
SGSubsystemRef create(const std::string& name);
template <class T>
SGSharedPtr<T> createInstance(const std::string& instanceName)
{
auto ref = createInstance(T::subsystemName(), instanceName);
return dynamic_cast<T*>(ref.ptr());
}
SGSubsystemRef createInstance(const std::string& name, const std::string& instanceName);
static GroupType defaultGroupFor(const char* name);
static double defaultUpdateIntervalFor(const char* name);
static const DependencyVec& dependsFor(const char* name);
/**
* @brief delegate to recieve notifications when the subsystem
* configuration changes. For any event/state change, a before (will)
* and after (did) change notifications are sent.
*/
class Delegate
{
public:
virtual void willChange(SGSubsystem* sub, SGSubsystem::State newState);
virtual void didChange(SGSubsystem* sub, SGSubsystem::State currentState);
};
void addDelegate(Delegate * d);
void removeDelegate(Delegate * d);
private:
friend class SGSubsystem;
friend class SGSubsystemGroup;
void notifyDelegatesWillChange(SGSubsystem* sub, State newState);
void notifyDelegatesDidChange(SGSubsystem* sub, State statee);
std::vector<SGSubsystemGroupRef> _groups;
unsigned int _initPosition = 0;
bool _destructorActive = false;
// non-owning reference, this is to accelerate lookup
// by name which otherwise needs a full walk of the entire tree
using SubsystemDict = std::map<std::string, SGSubsystem*>;
mutable SubsystemDict _subsystemNameCache;
using DelegateVec = std::vector<Delegate*>;
DelegateVec _delegates;
};
#endif // __SUBSYSTEM_MGR_HXX