+// 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
// 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.
+ * @return true if the flight was saved successfully.
+ */
extern bool fgSaveFlight (ostream &output);
+
+
+/**
+ * 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);
}
+/**
+ * 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.
+ */
inline bool fgGetBool (const string &name, bool defaultValue = false)
{
return globals->get_props()->getBoolValue(name, defaultValue);
}
+
+/**
+ * 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.
+ */
inline int fgGetInt (const string &name, int defaultValue = 0)
{
return globals->get_props()->getIntValue(name, defaultValue);
}
+
+/**
+ * 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.
+ */
inline int fgGetLong (const string &name, long defaultValue = 0L)
{
return globals->get_props()->getLongValue(name, defaultValue);
}
+
+/**
+ * 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.
+ */
inline float fgGetFloat (const string &name, float defaultValue = 0.0)
{
return globals->get_props()->getFloatValue(name, defaultValue);
}
+
+/**
+ * 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.
+ */
inline double fgGetDouble (const string &name, double defaultValue = 0.0)
{
return globals->get_props()->getDoubleValue(name, defaultValue);
}
+
+/**
+ * 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.
+ */
inline string fgGetString (const string &name, string defaultValue = "")
{
return globals->get_props()->getStringValue(name, 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.
+ */
inline bool fgSetBool (const string &name, bool val)
{
return globals->get_props()->setBoolValue(name, 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.
+ */
inline bool fgSetInt (const string &name, int val)
{
return globals->get_props()->setIntValue(name, 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.
+ */
inline bool fgSetLong (const string &name, long val)
{
return globals->get_props()->setLongValue(name, 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.
+ */
inline bool fgSetFloat (const string &name, float val)
{
return globals->get_props()->setFloatValue(name, 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.
+ */
inline bool fgSetDouble (const string &name, double val)
{
return globals->get_props()->setDoubleValue(name, 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.
+ */
inline bool fgSetString (const string &name, const string &val)
{
return globals->get_props()->setStringValue(name, val);
}
+\f
+////////////////////////////////////////////////////////////////////////
+// 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).
+ */
+inline void
+fgSetArchivable (const string &name, bool state = true)
+{
+ SGPropertyNode * node = globals->get_props()->getNode(name);
+ if (node == 0)
+ SG_LOG(SG_GENERAL, SG_ALERT,
+ "Attempt to set archive flag for non-existant property "
+ << name);
+ else
+ node->setAttribute(SGPropertyNode::ARCHIVE, state);
+}
+
+
+/**
+ * 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).
+ */
+inline void
+fgSetReadable (const string &name, bool state = true)
+{
+ SGPropertyNode * node = globals->get_props()->getNode(name);
+ if (node == 0)
+ SG_LOG(SG_GENERAL, SG_ALERT,
+ "Attempt to set read flag for non-existant property "
+ << name);
+ else
+ node->setAttribute(SGPropertyNode::READ, state);
+}
+
+
+/**
+ * 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).
+ */
+inline void
+fgSetWritable (const string &name, bool state = true)
+{
+ SGPropertyNode * node = globals->get_props()->getNode(name);
+ if (node == 0)
+ SG_LOG(SG_GENERAL, SG_ALERT,
+ "Attempt to set write flag for non-existant property "
+ << name);
+ else
+ node->setAttribute(SGPropertyNode::WRITE, state);
+}
+
+
\f
////////////////////////////////////////////////////////////////////////
// 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.
+ */
inline void
fgUntie (const string &name)
{
// Templates cause ambiguity here
+
+/**
+ * Tie a property to an external bool variable.
+ *
+ * The property's value will automatically mirror the variable's
+ * value, and vice-versa, until the property is untied.
+ *
+ * @param name The property name to tie (full path).
+ * @param pointer A pointer to the variable.
+ * @param useDefault true if any existing property value should be
+ * copied to the variable; false if the variable should not
+ * be modified; defaults to true.
+ */
inline void
fgTie (const string &name, bool *pointer, bool useDefault = true)
{
"Failed to tie property " << name << " to a pointer");
}
+
+/**
+ * Tie a property to an external int variable.
+ *
+ * The property's value will automatically mirror the variable's
+ * value, and vice-versa, until the property is untied.
+ *
+ * @param name The property name to tie (full path).
+ * @param pointer A pointer to the variable.
+ * @param useDefault true if any existing property value should be
+ * copied to the variable; false if the variable should not
+ * be modified; defaults to true.
+ */
inline void
fgTie (const string &name, int *pointer, bool useDefault = true)
{
"Failed to tie property " << name << " to a pointer");
}
+
+/**
+ * Tie a property to an external long variable.
+ *
+ * The property's value will automatically mirror the variable's
+ * value, and vice-versa, until the property is untied.
+ *
+ * @param name The property name to tie (full path).
+ * @param pointer A pointer to the variable.
+ * @param useDefault true if any existing property value should be
+ * copied to the variable; false if the variable should not
+ * be modified; defaults to true.
+ */
inline void
fgTie (const string &name, long *pointer, bool useDefault = true)
{
"Failed to tie property " << name << " to a pointer");
}
+
+/**
+ * Tie a property to an external float variable.
+ *
+ * The property's value will automatically mirror the variable's
+ * value, and vice-versa, until the property is untied.
+ *
+ * @param name The property name to tie (full path).
+ * @param pointer A pointer to the variable.
+ * @param useDefault true if any existing property value should be
+ * copied to the variable; false if the variable should not
+ * be modified; defaults to true.
+ */
inline void
fgTie (const string &name, float *pointer, bool useDefault = true)
{
"Failed to tie property " << name << " to a pointer");
}
+
+/**
+ * Tie a property to an external double variable.
+ *
+ * The property's value will automatically mirror the variable's
+ * value, and vice-versa, until the property is untied.
+ *
+ * @param name The property name to tie (full path).
+ * @param pointer A pointer to the variable.
+ * @param useDefault true if any existing property value should be
+ * copied to the variable; false if the variable should not
+ * be modified; defaults to true.
+ */
inline void
fgTie (const string &name, double *pointer, bool useDefault = true)
{
"Failed to tie property " << name << " to a pointer");
}
+
+/**
+ * Tie a property to an external string variable.
+ *
+ * The property's value will automatically mirror the variable's
+ * value, and vice-versa, until the property is untied.
+ *
+ * @param name The property name to tie (full path).
+ * @param pointer A pointer to the variable.
+ * @param useDefault true if any existing property value should be
+ * copied to the variable; false if the variable should not
+ * be modified; defaults to true.
+ */
inline void
fgTie (const string &name, string *pointer, bool useDefault = true)
{
"Failed to tie property " << name << " to a pointer");
}
+
+/**
+ * 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 <class V>
inline void
fgTie (const string &name, V (*getter)(), void (*setter)(V) = 0,
"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 <class V>
inline void
fgTie (const string &name, int index, V (*getter)(int),
"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 <class T, class V>
inline void
fgTie (const string &name, T * obj, V (T::*getter)() const,
"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 <class T, class V>
inline void
fgTie (const string &name, T * obj, int index,
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