Round millibars to nearest whole number, and make inches default even in UK until...

[flightgear.git] / src / Scripting / NasalSys.hxx

diff --git a/src/Scripting/NasalSys.hxx b/src/Scripting/NasalSys.hxx
index c1dfa92ad3483c8c3686c603916d228a4dd37a2b..8e584f9ebfe471ca75d3de2e677902daad9b10b5 100644 (file)
--- a/src/Scripting/NasalSys.hxx
+++ b/src/Scripting/NasalSys.hxx
@@ -5,6 +5,8 @@
 #include <simgear/structure/subsystem_mgr.hxx>
 #include <simgear/nasal/nasal.h>
 
+class FGNasalScript;
+
 class FGNasalSys : public SGSubsystem
 {
 public:
@@ -13,21 +15,32 @@ public:
     virtual void init();
     virtual void update(double dt) { /* noop */ }
 
-    virtual bool handleCommand(const SGPropertyNode* arg);
-
     // Simple hook to run arbitrary source code.  Returns a bool to
     // indicate successful execution.  Does *not* return any Nasal
     // values, because handling garbage-collected objects from C space
     // is deep voodoo and violates the "simple hook" idea.
     bool parseAndRun(const char* sourceCode);
 
+    // Slightly more complicated hook to get a handle to a precompiled
+    // Nasal script that can be invoked via a call() method.  The
+    // caller is expected to delete the FGNasalScript returned from
+    // this function.  The "name" argument specifies the "file name"
+    // for the source code that will be printed in Nasal stack traces
+    // on error.
+    FGNasalScript* parseScript(const char* src, const char* name=0);
+
     // Implementation of the settimer extension function
     void setTimer(naRef args);
 
     // Returns a ghost wrapper for the current _cmdArg
     naRef cmdArgGhost();
     
+    // Callbacks for command and timer bindings
+    virtual bool handleCommand(const SGPropertyNode* arg);
+
 private:
+    friend class FGNasalScript;
+
     //
     // FGTimer subclass for handling Nasal timer callbacks.
     // See the implementation of the settimer() extension function for
@@ -36,7 +49,7 @@ private:
     struct NasalTimer {
         virtual void timerExpired();
         naRef handler;
-        int hashKey;
+        int gcKey;
         FGNasalSys* nasal;
     };
 
@@ -46,20 +59,44 @@ private:
     void readScriptFile(SGPath file, const char* lib);
     void hashset(naRef hash, const char* key, naRef val);
     void logError();
-    naRef parse(const char* filename, const char* buf, int len);
+    naRef parse(const char* filename, const char* buf, int len=0);
     naRef genPropsModule();
     naRef propNodeGhost(SGPropertyNode* handle);
 
+    // This mechanism is here to allow naRefs to be passed to
+    // locations "outside" the interpreter.  Normally, such a
+    // reference would be garbage collected unexpectedly.  By passing
+    // it to gcSave and getting a key/handle, it can be cached in a
+    // globals.__gcsave hash.  Be sure to release it with gcRelease
+    // when done.
+    int gcSave(naRef r);
+    void gcRelease(int key);
+
     naContext _context;
     naRef _globals;
-    naRef _timerHash;
 
     SGPropertyNode* _cmdArg;
 
-    int _nextTimerHashKey;
+    int _nextGCKey;
+    naRef _gcHash;
+
+    public: void handleTimer(NasalTimer* t);
+};
 
+class FGNasalScript {
 public:
-         void handleTimer(NasalTimer* t);
+    ~FGNasalScript() { _nas->gcRelease(_gcKey); }
+
+    bool call() {
+        naCall(_nas->_context, _code, naNil(), naNil(), naNil());
+        return naGetError(_nas->_context) == 0;
+    }
+
+private:
+    friend class FGNasalSys;
+    naRef _code;
+    int _gcKey;
+    FGNasalSys* _nas;
 };
 
 #endif // __NASALSYS_HXX