// fg_props.hxx - Declarations and inline methods for property handling. // Written by David Megginson, started 2000. // // This file is in the Public Domain, and comes with no warranty. #ifndef __FG_PROPS_HXX #define __FG_PROPS_HXX 1 #include #include #include #include "globals.hxx" //////////////////////////////////////////////////////////////////////// // Property management. //////////////////////////////////////////////////////////////////////// /** * Initialize the default FlightGear properties. * * These are mostly properties that haven't been claimed by a * specific module yet. This function should be invoked once, * while the program is starting (and after the global property * tree has been created). */ extern void fgInitProps (); // fixme: how are they untied? /** * Update the default FlightGear properties. * * This function should be invoked once in each loop to update all * of the default properties. */ extern void fgUpdateProps (); /** * Save a flight to disk. * * This function saves all of the archivable properties to a stream * so that the current flight can be restored later. * * @param output The output stream to write the XML save file to. * @param write_all If true, write all properties rather than * just the ones flagged as archivable. * @return true if the flight was saved successfully. */ extern bool fgSaveFlight (ostream &output, bool write_all = false); /** * Load a flight from disk. * * This function loads an XML save file from a stream to restore * a flight. * * @param input The input stream to read the XML from. * @return true if the flight was restored successfully. */ extern bool fgLoadFlight (istream &input); //////////////////////////////////////////////////////////////////////// // Convenience functions for getting property values. //////////////////////////////////////////////////////////////////////// /** * Get a property node. * * @param path The path of the node, relative to root. * @param create true to create the node if it doesn't exist. * @return The node, or 0 if none exists and none was created. */ extern SGPropertyNode * fgGetNode (const char * path, bool create = false); /** * Get a property node with separate index. * * This method separates the index from the path string, to make it * easier to iterate through multiple components without using sprintf * to add indices. For example, fgGetNode("foo[1]/bar", 3) will * return the same result as fgGetNode("foo[1]/bar[3]"). * * @param path The path of the node, relative to root. * @param index The index for the last member of the path (overrides * any given in the string). * @param create true to create the node if it doesn't exist. * @return The node, or 0 if none exists and none was created. */ extern SGPropertyNode * fgGetNode (const char * path, int index, bool create = false); /** * Test whether a given node exists. * * @param path The path of the node, relative to root. * @return true if the node exists, false otherwise. */ extern bool fgHasNode (const char * path); /** * Add a listener to a node. * * @param listener The listener to add to the node. * @param path The path of the node, relative to root. * @param index The index for the last member of the path (overrides * any given in the string). */ extern void fgAddChangeListener (SGPropertyChangeListener * listener, const char * path); /** * Add a listener to a node. * * @param listener The listener to add to the node. * @param path The path of the node, relative to root. * @param index The index for the last member of the path (overrides * any given in the string). */ extern void fgAddChangeListener (SGPropertyChangeListener * listener, const char * path, int index); /** * Get a bool value for a property. * * This method is convenient but inefficient. It should be used * infrequently (i.e. for initializing, loading, saving, etc.), * not in the main loop. If you need to get a value frequently, * it is better to look up the node itself using fgGetNode and then * use the node's getBoolValue() method, to avoid the lookup overhead. * * @param name The property name. * @param defaultValue The default value to return if the property * does not exist. * @return The property's value as a bool, or the default value provided. */ extern bool fgGetBool (const char * name, bool defaultValue = false); /** * Get an int value for a property. * * This method is convenient but inefficient. It should be used * infrequently (i.e. for initializing, loading, saving, etc.), * not in the main loop. If you need to get a value frequently, * it is better to look up the node itself using fgGetNode and then * use the node's getIntValue() method, to avoid the lookup overhead. * * @param name The property name. * @param defaultValue The default value to return if the property * does not exist. * @return The property's value as an int, or the default value provided. */ extern int fgGetInt (const char * name, int defaultValue = 0); /** * Get a long value for a property. * * This method is convenient but inefficient. It should be used * infrequently (i.e. for initializing, loading, saving, etc.), * not in the main loop. If you need to get a value frequently, * it is better to look up the node itself using fgGetNode and then * use the node's getLongValue() method, to avoid the lookup overhead. * * @param name The property name. * @param defaultValue The default value to return if the property * does not exist. * @return The property's value as a long, or the default value provided. */ extern int fgGetLong (const char * name, long defaultValue = 0L); /** * Get a float value for a property. * * This method is convenient but inefficient. It should be used * infrequently (i.e. for initializing, loading, saving, etc.), * not in the main loop. If you need to get a value frequently, * it is better to look up the node itself using fgGetNode and then * use the node's getFloatValue() method, to avoid the lookup overhead. * * @param name The property name. * @param defaultValue The default value to return if the property * does not exist. * @return The property's value as a float, or the default value provided. */ extern float fgGetFloat (const char * name, float defaultValue = 0.0); /** * Get a double value for a property. * * This method is convenient but inefficient. It should be used * infrequently (i.e. for initializing, loading, saving, etc.), * not in the main loop. If you need to get a value frequently, * it is better to look up the node itself using fgGetNode and then * use the node's getDoubleValue() method, to avoid the lookup overhead. * * @param name The property name. * @param defaultValue The default value to return if the property * does not exist. * @return The property's value as a double, or the default value provided. */ extern double fgGetDouble (const char * name, double defaultValue = 0.0); /** * Get a string value for a property. * * This method is convenient but inefficient. It should be used * infrequently (i.e. for initializing, loading, saving, etc.), * not in the main loop. If you need to get a value frequently, * it is better to look up the node itself using fgGetNode and then * use the node's getStringValue() method, to avoid the lookup overhead. * * @param name The property name. * @param defaultValue The default value to return if the property * does not exist. * @return The property's value as a string, or the default value provided. */ extern const char * fgGetString (const char * name, const char * defaultValue = ""); /** * Set a bool value for a property. * * Assign a bool value to a property. If the property does not * yet exist, it will be created and its type will be set to * BOOL; if it has a type of UNKNOWN, the type will also be set to * BOOL; otherwise, the bool value will be converted to the property's * type. * * @param name The property name. * @param val The new value for the property. * @return true if the assignment succeeded, false otherwise. */ extern bool fgSetBool (const char * name, bool val); /** * Set an int value for a property. * * Assign an int value to a property. If the property does not * yet exist, it will be created and its type will be set to * INT; if it has a type of UNKNOWN, the type will also be set to * INT; otherwise, the bool value will be converted to the property's * type. * * @param name The property name. * @param val The new value for the property. * @return true if the assignment succeeded, false otherwise. */ extern bool fgSetInt (const char * name, int val); /** * Set a long value for a property. * * Assign a long value to a property. If the property does not * yet exist, it will be created and its type will be set to * LONG; if it has a type of UNKNOWN, the type will also be set to * LONG; otherwise, the bool value will be converted to the property's * type. * * @param name The property name. * @param val The new value for the property. * @return true if the assignment succeeded, false otherwise. */ extern bool fgSetLong (const char * name, long val); /** * Set a float value for a property. * * Assign a float value to a property. If the property does not * yet exist, it will be created and its type will be set to * FLOAT; if it has a type of UNKNOWN, the type will also be set to * FLOAT; otherwise, the bool value will be converted to the property's * type. * * @param name The property name. * @param val The new value for the property. * @return true if the assignment succeeded, false otherwise. */ extern bool fgSetFloat (const char * name, float val); /** * Set a double value for a property. * * Assign a double value to a property. If the property does not * yet exist, it will be created and its type will be set to * DOUBLE; if it has a type of UNKNOWN, the type will also be set to * DOUBLE; otherwise, the double value will be converted to the property's * type. * * @param name The property name. * @param val The new value for the property. * @return true if the assignment succeeded, false otherwise. */ extern bool fgSetDouble (const char * name, double val); /** * Set a string value for a property. * * Assign a string value to a property. If the property does not * yet exist, it will be created and its type will be set to * STRING; if it has a type of UNKNOWN, the type will also be set to * STRING; otherwise, the string value will be converted to the property's * type. * * @param name The property name. * @param val The new value for the property. * @return true if the assignment succeeded, false otherwise. */ extern bool fgSetString (const char * name, const char * val); //////////////////////////////////////////////////////////////////////// // Convenience functions for setting property attributes. //////////////////////////////////////////////////////////////////////// /** * Set the state of the archive attribute for a property. * * If the archive attribute is true, the property will be written * when a flight is saved; if it is false, the property will be * skipped. * * A warning message will be printed if the property does not exist. * * @param name The property name. * @param state The state of the archive attribute (defaults to true). */ extern void fgSetArchivable (const char * name, bool state = true); /** * Set the state of the read attribute for a property. * * If the read attribute is true, the property value will be readable; * if it is false, the property value will always be the default value * for its type. * * A warning message will be printed if the property does not exist. * * @param name The property name. * @param state The state of the read attribute (defaults to true). */ extern void fgSetReadable (const char * name, bool state = true); /** * Set the state of the write attribute for a property. * * If the write attribute is true, the property value may be modified * (depending on how it is tied); if the write attribute is false, the * property value may not be modified. * * A warning message will be printed if the property does not exist. * * @param name The property name. * @param state The state of the write attribute (defaults to true). */ extern void fgSetWritable (const char * name, bool state = true); //////////////////////////////////////////////////////////////////////// // Convenience functions for tying properties, with logging. //////////////////////////////////////////////////////////////////////// /** * Untie a property from an external data source. * * Classes should use this function to release control of any * properties they are managing. */ extern void fgUntie (const char * name); /** * Tie a property to a pair of simple functions. * * Every time the property value is queried, the getter (if any) will * be invoked; every time the property value is modified, the setter * (if any) will be invoked. The getter can be 0 to make the property * unreadable, and the setter can be 0 to make the property * unmodifiable. * * @param name The property name to tie (full path). * @param getter The getter function, or 0 if the value is unreadable. * @param setter The setter function, or 0 if the value is unmodifiable. * @param useDefault true if the setter should be invoked with any existing * property value should be; false if the old value should be * discarded; defaults to true. */ template inline void fgTie (const char * name, V (*getter)(), void (*setter)(V) = 0, bool useDefault = true) { if (!globals->get_props()->tie(name, SGRawValueFunctions(getter, setter), useDefault)) SG_LOG(SG_GENERAL, SG_WARN, "Failed to tie property " << name << " to functions"); } /** * Tie a property to a pair of indexed functions. * * Every time the property value is queried, the getter (if any) will * be invoked with the index provided; every time the property value * is modified, the setter (if any) will be invoked with the index * provided. The getter can be 0 to make the property unreadable, and * the setter can be 0 to make the property unmodifiable. * * @param name The property name to tie (full path). * @param index The integer argument to pass to the getter and * setter functions. * @param getter The getter function, or 0 if the value is unreadable. * @param setter The setter function, or 0 if the value is unmodifiable. * @param useDefault true if the setter should be invoked with any existing * property value should be; false if the old value should be * discarded; defaults to true. */ template inline void fgTie (const char * name, int index, V (*getter)(int), void (*setter)(int, V) = 0, bool useDefault = true) { if (!globals->get_props()->tie(name, SGRawValueFunctionsIndexed(index, getter, setter), useDefault)) SG_LOG(SG_GENERAL, SG_WARN, "Failed to tie property " << name << " to indexed functions"); } /** * Tie a property to a pair of object methods. * * Every time the property value is queried, the getter (if any) will * be invoked; every time the property value is modified, the setter * (if any) will be invoked. The getter can be 0 to make the property * unreadable, and the setter can be 0 to make the property * unmodifiable. * * @param name The property name to tie (full path). * @param obj The object whose methods should be invoked. * @param getter The object's getter method, or 0 if the value is * unreadable. * @param setter The object's setter method, or 0 if the value is * unmodifiable. * @param useDefault true if the setter should be invoked with any existing * property value should be; false if the old value should be * discarded; defaults to true. */ template inline void fgTie (const char * name, T * obj, V (T::*getter)() const, void (T::*setter)(V) = 0, bool useDefault = true) { if (!globals->get_props()->tie(name, SGRawValueMethods(*obj, getter, setter), useDefault)) SG_LOG(SG_GENERAL, SG_WARN, "Failed to tie property " << name << " to object methods"); } /** * Tie a property to a pair of indexed object methods. * * Every time the property value is queried, the getter (if any) will * be invoked with the index provided; every time the property value * is modified, the setter (if any) will be invoked with the index * provided. The getter can be 0 to make the property unreadable, and * the setter can be 0 to make the property unmodifiable. * * @param name The property name to tie (full path). * @param obj The object whose methods should be invoked. * @param index The integer argument to pass to the getter and * setter methods. * @param getter The getter method, or 0 if the value is unreadable. * @param setter The setter method, or 0 if the value is unmodifiable. * @param useDefault true if the setter should be invoked with any existing * property value should be; false if the old value should be * discarded; defaults to true. */ template inline void fgTie (const char * name, T * obj, int index, V (T::*getter)(int) const, void (T::*setter)(int, V) = 0, bool useDefault = true) { if (!globals->get_props()->tie(name, SGRawValueMethodsIndexed(*obj, index, getter, setter), useDefault)) SG_LOG(SG_GENERAL, SG_WARN, "Failed to tie property " << name << " to indexed object methods"); } //////////////////////////////////////////////////////////////////////// // Conditions. //////////////////////////////////////////////////////////////////////// /** * An encoded condition. * * This class encodes a single condition of some sort, possibly * connected with properties. * * This class should migrate to somewhere more general. */ class FGCondition { public: FGCondition (); virtual ~FGCondition (); virtual bool test () const = 0; }; /** * Condition for a single property. * * This condition is true only if the property returns a boolean * true value. */ class FGPropertyCondition : public FGCondition { public: FGPropertyCondition (const char * propname); virtual ~FGPropertyCondition (); virtual bool test () const { return _node->getBoolValue(); } private: const SGPropertyNode * _node; }; /** * Condition for a 'not' operator. * * This condition is true only if the child condition is false. */ class FGNotCondition : public FGCondition { public: // transfer pointer ownership FGNotCondition (FGCondition * condition); virtual ~FGNotCondition (); virtual bool test () const; private: FGCondition * _condition; }; /** * Condition for an 'and' group. * * This condition is true only if all of the conditions * in the group are true. */ class FGAndCondition : public FGCondition { public: FGAndCondition (); virtual ~FGAndCondition (); virtual bool test () const; // transfer pointer ownership virtual void addCondition (FGCondition * condition); private: vector _conditions; }; /** * Condition for an 'or' group. * * This condition is true if at least one of the conditions in the * group is true. */ class FGOrCondition : public FGCondition { public: FGOrCondition (); virtual ~FGOrCondition (); virtual bool test () const; // transfer pointer ownership virtual void addCondition (FGCondition * condition); private: vector _conditions; }; /** * Abstract base class for property comparison conditions. */ class FGComparisonCondition : public FGCondition { public: enum Type { LESS_THAN, GREATER_THAN, EQUALS }; FGComparisonCondition (Type type, bool reverse = false); virtual ~FGComparisonCondition (); virtual bool test () const; virtual void setLeftProperty (const char * propname); virtual void setRightProperty (const char * propname); // will make a local copy virtual void setRightValue (const SGPropertyNode * value); private: Type _type; bool _reverse; const SGPropertyNode * _left_property; const SGPropertyNode * _right_property; const SGPropertyNode * _right_value; }; /** * Base class for a conditional components. * * This class manages the conditions and tests; the component should * invoke the test() method whenever it needs to decide whether to * active itself, draw itself, and so on. */ class FGConditional { public: FGConditional (); virtual ~FGConditional (); // transfer pointer ownership virtual void setCondition (FGCondition * condition); virtual const FGCondition * getCondition () const { return _condition; } virtual bool test () const; private: FGCondition * _condition; }; /** * Global function to make a condition out of properties. * * The top-level is always an implicit 'and' group, whatever the * node's name (it should usually be "condition"). * * @param node The top-level condition node (usually named "condition"). * @return A pointer to a newly-allocated condition; it is the * responsibility of the caller to delete the condition when * it is no longer needed. */ FGCondition * fgReadCondition (const SGPropertyNode * node); #endif // __FG_PROPS_HXX