jsicontext.hpp

OSB-PIK-OpenVXI-3.0.0源代码 “中国XML论坛 - 专业的XML技术讨论区--XML在语音技术中的应用”

 /****************License************************************************
  *
  * Copyright 2000-2003.  ScanSoft, Inc.    
  *
  * Use of this software is subject to notices and obligations set forth 
  * in the SpeechWorks Public License - Software Version 1.2 which is 
  * included with this software. 
  *
  * ScanSoft is a registered trademark of ScanSoft, Inc., and OpenSpeech, 
  * SpeechWorks and the SpeechWorks logo are registered trademarks or 
  * trademarks of SpeechWorks International, Inc. in the United States 
  * and other countries.
  *
  ***********************************************************************/
 

 /*****************************************************************************
  *****************************************************************************
  *
  *
  * JsiContext, class for managing JavaScript contexts
  *
  * The JsiContext class represents a JavaScript context, a script
  * execution state. All JavaScript variables are maintained in a
  * context, and all scripts are executed in reference to a context
  * (for accessing variables and maintaining script side-effects). Each
  * context may have one or more scopes that are used to layer the
  * state information so that it is possible for clients to control the
  * lifetime of state information within the context.
  *
  *****************************************************************************
  ****************************************************************************/
 
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 #ifndef _JSI_CONTEXT_H__
 #define _JSI_CONTEXT_H__
 
 #include "VXIjsi.h"              // For VXIjsiResult codes
 #include "SBjsiString.hpp"      // For SBinetString class
 #include "SBjsiLogger.hpp"      // For SBjsiLogger base class
 
 #ifndef HAVE_SPIDERMONKEY
 #error Need Mozilla SpiderMonkey to build this ECMAScript integration
 #endif
 #include <jsapi.h>               // SpiderMonkey API, for typedefs
 
 #ifndef JS_DLL_CALLBACK
 #define JS_DLL_CALLBACK CRT_CALL // For SpiderMonkey 1.5 RC 3 and earlier
 #endif
 
 class JsiRuntime;
 class JsiProtectedJsval;
 class JsiScopeChainNode;
 extern "C" struct VXIlogInterface;
 
 class JsiContext : public SBjsiLogger {
  public:
   // Constructor and destructor
   JsiContext( );
   virtual ~JsiContext( );
 
   // Creation method
   VXIjsiResult Create (JsiRuntime        *runtime, 
 		       long               contextSize, 
 		       long               maxBranches,
 		       VXIlogInterface   *log,
 		       VXIunsigned        diagTagBase);
 
   // Create a script variable relative to the current scope
   VXIjsiResult CreateVar (const VXIchar  *name, 
 			  const VXIchar  *expr);
   VXIjsiResult CreateVar (const VXIchar  *name, 
 			  const VXIValue *value);
   
   // Set a script variable relative to the current scope
   VXIjsiResult SetVar (const VXIchar     *name, 
 		       const VXIchar     *expr);
   VXIjsiResult SetVar (const VXIchar     *name, 
 		       const VXIValue    *value);
   
   // Get the value of a variable
   VXIjsiResult GetVar (const VXIchar     *name,
 		       VXIValue         **value) const;
   
   // Check whether a variable is defined (not void, could be NULL)
   VXIjsiResult CheckVar (const VXIchar   *name) const;
 
 	// Set the given variable to read-only attribute
   VXIjsiResult SetReadOnly(const VXIchar *name) const;
   
   // Execute a script, optionally returning any execution result
   VXIjsiResult Eval (const VXIchar       *expr,
 		     VXIValue           **result);
   
   // Push a new context onto the scope chain (add a nested scope);
   VXIjsiResult PushScope (const VXIchar  *name, const VXIjsiScopeAttr attr);
 
   // Pop a context from the scope chain (remove a nested scope);
   VXIjsiResult PopScope( );
   
   // Reset the scope chain to the global scope (pop all nested scopes);
   VXIjsiResult ClearScopes( );
    
  private:
   // NOTE: Internal methods, these do not do mutex locking
 
   // Flag that we are starting and stopping execution of a script,
   // used to ensure thread safety. For simplicity, return true on
   // success, false on failure (mutex error). For the threadsafe
   // build, this is really disabling/enabling garbage collection.  For
   // the non-threadsafe build this is doing mutex locks.
   bool AccessBegin( ) const { 
 #ifdef JS_THREADSAFE
     JS_ResumeRequest (context, contextRefs);
     return true;
 #else
     return runtime->AccessBegin( );
 #endif
   }
 
   bool AccessEnd( ) const {
 #ifdef JS_THREADSAFE
     JsiContext *pThis = (JsiContext *) this;
     pThis->contextRefs = JS_SuspendRequest (context);
 #endif
 #ifdef JSI_MEMORY_TEST
     // Do garbage collection to invalidate memory, use this during unit
     // test/Purify runs to make sure we're extremely clean
     if ( context ) JS_GC (context);
 #endif
 #ifdef JS_THREADSAFE
     return true;
 #else
     return runtime->AccessEnd( );
 #endif
   }
   
   // Script evaluation
   VXIjsiResult EvaluateScript (const VXIchar *script, 
 			       JsiProtectedJsval *retval = NULL,
 			       bool loggingEnabled = true) const;
 
   // Convert JS values to VXIValue types and vice versa
   static VXIjsiResult JsvalToVXIValue (JSContext *context,
 				       const jsval val,
 				       VXIValue **value);
   VXIjsiResult VXIValueToJsval (JSContext *context,
 				const VXIValue *value,
 				JsiProtectedJsval *val);
 
   // Reset for the next evaluation
   void EvaluatePrepare (bool enableLog = true) const { 
     JsiContext *pThis = const_cast<JsiContext *>(this);
     pThis->logEnabled = enableLog;
     pThis->numBranches = 0L;
     if ( pThis->exception ) { 
       VXIValueDestroy (&pThis->exception); pThis->exception = NULL; }
   }
 
   // Check if the variable name is valid at declaration
 	bool IsValidVarName(JSContext *context, JSObject *obj, const VXIchar* vname);
 	
 	// Check if the scope is writeable
 	VXIjsiResult CheckWriteable(JSContext *context, JSObject *obj, const VXIchar* varname);
 	
   // Disable the copy constructor and assignment operator
   JsiContext (const JsiContext &src);
   JsiContext & operator= (const JsiContext &src);
 
  public:
   // NOTE: Internal static methods, these do not do mutex locking
 
   // Static callback for finalizing scopes
   static void JS_DLL_CALLBACK ScopeFinalize (JSContext *cx, JSObject *obj);
 
   // Static callback for finalizing content objects
   static void JS_DLL_CALLBACK ContentFinalize (JSContext *cx, JSObject *obj);
 
   // Static callback for enforcing maxBranches
   static JSBool JS_DLL_CALLBACK BranchCallback (JSContext *context, 
 						JSScript *script);
 
   // Static callback for reporting JavaScript errors
   static void JS_DLL_CALLBACK ErrorReporter (JSContext *context, 
 					     const char *message,
 					     JSErrorReport *report);
 
 	static JSBool JS_DLL_CALLBACK SCOPE_CLASS_SetProperty(JSContext *cx, JSObject *obj, jsval id, jsval *vp);
 		
  private:
   JSVersion           version;           // JavaScript version
   JsiRuntime         *runtime;           // JavaScript runtime environment
   JSContext          *context;           // Underlying SpiderMonkey context
   jsrefcount          contextRefs;       // Reference count for the context
   JsiScopeChainNode  *scopeChain;        // Scope chain
   JsiScopeChainNode  *currentScope;      // Current (leaf) scope
 
   // Evaluation state information
   bool      logEnabled;      /* Whether to log JavaScript errors */
   long      maxBranches;     /* Maximum number of branches for each 
 			        evaluation */
   long      numBranches;     /* Number of branches for the current evaluation,
 		 	        used to enforce maxBranches */
   VXIValue *exception;      /* Exception data, NULL if no exception */
 
 
 };
 
 #endif  // _JSI_CONTEXT_H__