# include <config.h>
#endif
-#ifdef SG_MATH_EXCEPTION_CLASH
-# include <math.h>
-#endif
+#include <simgear/compiler.h>
+
+// #ifdef SG_MATH_EXCEPTION_CLASH
+// # include <math.h>
+// #endif
#ifdef HAVE_WINDOWS_H
# include <windows.h>
# include <float.h>
#endif
+#include STL_STRING
+SG_USING_STD(string);
+
+#include <vector>
+SG_USING_STD(vector);
+
+#include <map>
+SG_USING_STD(map);
+
+#include <simgear/props/props.hxx>
+
\f
/**
* 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 FGSubsystem
{
public:
+
+ /**
+ * Default constructor.
+ */
+ FGSubsystem ();
+
+ /**
+ * Virtual destructor to ensure that subclass destructors are called.
+ */
virtual ~FGSubsystem ();
- virtual void init () = 0;
- virtual void bind () = 0;
- virtual void unbind () = 0;
- virtual void update () = 0;
+
+ /**
+ * 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 ();
+
+
+ /**
+ * Reinitialize the subsystem.
+ *
+ * <p>This method should cause the subsystem to reinitialize itself,
+ * and (normally) to reload any configuration files.</p>
+ */
+ virtual void reinit ();
+
+
+ /**
+ * 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 resum 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;
+
+
+protected:
+
+ mutable SGPropertyNode_ptr _freeze_master_node;
+ bool _suspended;
+
};
+\f
+/**
+ * A group of FlightGear subsystems.
+ */
+class FGSubsystemGroup : public FGSubsystem
+{
+public:
+
+ FGSubsystemGroup ();
+ virtual ~FGSubsystemGroup ();
+
+ virtual void init ();
+ virtual void reinit ();
+ virtual void bind ();
+ virtual void unbind ();
+ virtual void update (double delta_time_sec);
+ virtual void suspend ();
+ virtual void resume ();
+ virtual bool is_suspended () const;
+
+ virtual void set_subsystem (const string &name,
+ FGSubsystem * subsystem,
+ double min_step_sec = 0);
+ virtual FGSubsystem * get_subsystem (const string &name);
+ virtual void remove_subsystem (const string &name);
+ virtual bool has_subsystem (const string &name) const;
+
+private:
+
+ struct Member {
+
+ Member ();
+ Member (const Member &member);
+ virtual ~Member ();
+
+ virtual void update (double delta_time_sec);
+
+ string name;
+ FGSubsystem * subsystem;
+ double min_step_sec;
+ double elapsed_sec;
+ };
+
+ Member * get_member (const string &name, bool create = false);
+
+ vector<Member *> _members;
+};
+
+
+\f
+/**
+ * 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 FGSubsystemMgr : public FGSubsystem
+{
+public:
+
+ /**
+ * Types of subsystem groups.
+ */
+ enum GroupType {
+ INIT = 0,
+ GENERAL,
+ MAX_GROUPS
+ };
+
+ FGSubsystemMgr ();
+ virtual ~FGSubsystemMgr ();
+
+ virtual void init ();
+ virtual void reinit ();
+ virtual void bind ();
+ virtual void unbind ();
+ virtual void update (double delta_time_sec);
+ virtual void suspend ();
+ virtual void resume ();
+ virtual bool is_suspended () const;
+
+ virtual void add (const char * name,
+ FGSubsystem * subsystem,
+ GroupType group = GENERAL,
+ double min_time_sec = 0);
+
+ virtual FGSubsystemGroup * get_group (GroupType group);
+
+ virtual FGSubsystem * get_subsystem(const string &name);
+
+private:
+
+ FGSubsystemGroup _groups[MAX_GROUPS];
+ map<string,FGSubsystem *> _subsystem_map;
+
+};
+
+
+
#endif // __FGFS_HXX
// end of fgfs.hxx
projects / flightgear.git / blobdiff