JavaScriptCore/bindings/runtime_root.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2004 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include "config.h"

 #include "object.h"
 #include "runtime_root.h"
 #include <wtf/HashCountedSet.h>

 namespace KJS { namespace Bindings {

 // Java does NOT always call finalize (and thus KJS_JSObject_JSFinalize) when
 // it collects an objects.  This presents some difficulties.  We must ensure
 // the a JavaJSObject's corresponding JavaScript object doesn't get collected.  We
 // do this by incrementing the JavaScript's reference count the first time we
 // create a JavaJSObject for it, and decrementing the JavaScript reference count when
 // the last JavaJSObject that refers to it is finalized, or when the applet is
 // shutdown.
 //
 // To do this we keep a map that maps each applet instance
 // to the JavaScript objects it is referencing.  For each JavaScript instance
 // we also maintain a secondary reference count.  When that reference count reaches
 // 1 OR the applet is shutdown we deref the JavaScript instance.  Applet instances
 // are represented by a jlong.

 typedef HashMap<const RootObject*, ReferencesSet*> ReferencesByRootMap;

 static ReferencesByRootMap* getReferencesByRootMap()
 {
     static ReferencesByRootMap* referencesByRootMap = 0;

     if (!referencesByRootMap)
         referencesByRootMap = new ReferencesByRootMap;

     return referencesByRootMap;
 }

 static ReferencesSet* getReferencesSet(const RootObject* rootObject)
 {
     ReferencesByRootMap* refsByRoot = getReferencesByRootMap();
     ReferencesSet* referencesSet = 0;

     referencesSet = refsByRoot->get(rootObject);
     if (!referencesSet) {
         referencesSet  = new ReferencesSet;
         refsByRoot->add(rootObject, referencesSet);
     }
     return referencesSet;
 }

 // Scan all the dictionary for all the roots to see if any have a
 // reference to the imp, and if so, return it's reference count
 // dictionary.
 // FIXME:  This is a potential performance bottleneck with many applets.  We could fix be adding a
 // imp to root dictionary.
 ReferencesSet* findReferenceSet(JSObject* imp)
 {
     ReferencesByRootMap* refsByRoot = getReferencesByRootMap ();
     if (refsByRoot) {
         ReferencesByRootMap::const_iterator end = refsByRoot->end();
         for (ReferencesByRootMap::const_iterator it = refsByRoot->begin(); it != end; ++it) {
             ReferencesSet* set = it->second;

             if (set->contains(imp))
                 return set;
         }
     }

     return 0;
 }

 // FIXME:  This is a potential performance bottleneck with many applets.  We could fix be adding a
 // imp to root dictionary.
 const RootObject* rootObjectForImp (JSObject* imp)
 {
     ReferencesByRootMap* refsByRoot = getReferencesByRootMap ();
     const RootObject* rootObject = 0;

     if (refsByRoot) {
         ReferencesByRootMap::const_iterator end = refsByRoot->end();
         for (ReferencesByRootMap::const_iterator it = refsByRoot->begin(); it != end; ++it) {
             ReferencesSet* set = it->second;
             if (set->contains(imp)) {
                 rootObject = it->first;
                 break;
             }
         }
     }

     return rootObject;
 }

 const RootObject* rootObjectForInterpreter(Interpreter* interpreter)
 {
     ReferencesByRootMap* refsByRoot = getReferencesByRootMap ();

     if (refsByRoot) {
         ReferencesByRootMap::const_iterator end = refsByRoot->end();
         for (ReferencesByRootMap::const_iterator it = refsByRoot->begin(); it != end; ++it) {
             const RootObject* aRootObject = it->first;

             if (aRootObject->interpreter() == interpreter)
                 return aRootObject;
         }
     }

     return 0;
 }

 void addNativeReference(const RootObject* rootObject, JSObject* imp)
 {
     if (rootObject) {
         ReferencesSet* referenceMap = getReferencesSet(rootObject);

         unsigned numReferences = referenceMap->count(imp);
         if (numReferences == 0) {
             JSLock lock;
             gcProtect(imp);
         }
         referenceMap->add(imp);
     }
 }

 void removeNativeReference(JSObject* imp)
 {
     if (!imp)
         return;

     ReferencesSet *referencesSet = findReferenceSet(imp);
     if (referencesSet) {
         unsigned numReferences = referencesSet->count(imp);

         if (numReferences == 1) {
             JSLock lock;
             gcUnprotect(imp);
         }
         referencesSet->remove(imp);
     }
 }

 #if PLATFORM(MAC)
 // May only be set by dispatchToJavaScriptThread().
 static CFRunLoopSourceRef completionSource;

 static void completedJavaScriptAccess (void *i)
 {
     assert (CFRunLoopGetCurrent() != RootObject::runLoop());

     JSObjectCallContext *callContext = (JSObjectCallContext *)i;
     CFRunLoopRef runLoop = (CFRunLoopRef)callContext->originatingLoop;

     assert (CFRunLoopGetCurrent() == runLoop);

     CFRunLoopStop(runLoop);
 }

 static pthread_once_t javaScriptAccessLockOnce = PTHREAD_ONCE_INIT;
 static pthread_mutex_t javaScriptAccessLock;
 static int javaScriptAccessLockCount = 0;

 static void initializeJavaScriptAccessLock()
 {
     pthread_mutexattr_t attr;

     pthread_mutexattr_init(&attr);
     pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);

     pthread_mutex_init(&javaScriptAccessLock, &attr);
 }

 static inline void lockJavaScriptAccess()
 {
     // Perhaps add deadlock detection?
     pthread_once(&javaScriptAccessLockOnce, initializeJavaScriptAccessLock);
     pthread_mutex_lock(&javaScriptAccessLock);
     javaScriptAccessLockCount++;
 }

 static inline void unlockJavaScriptAccess()
 {
     javaScriptAccessLockCount--;
     pthread_mutex_unlock(&javaScriptAccessLock);
 }


 void RootObject::dispatchToJavaScriptThread(JSObjectCallContext *context)
 {
     // This lock guarantees that only one thread can invoke
     // at a time, and also guarantees that completionSource;
     // won't get clobbered.
     lockJavaScriptAccess();

     CFRunLoopRef currentRunLoop = CFRunLoopGetCurrent();

     assert (currentRunLoop != RootObject::runLoop());

     // Setup a source to signal once the invocation of the JavaScript
     // call completes.
     //
     // FIXME:  This could be a potential performance issue.  Creating and
     // adding run loop sources is expensive.  We could create one source
     // per thread, as needed, instead.
     context->originatingLoop = currentRunLoop;
     CFRunLoopSourceContext sourceContext = {0, context, NULL, NULL, NULL, NULL, NULL, NULL, NULL, completedJavaScriptAccess};
     completionSource = CFRunLoopSourceCreate(NULL, 0, &sourceContext);
     CFRunLoopAddSource(currentRunLoop, completionSource, kCFRunLoopDefaultMode);

     // Wakeup JavaScript access thread and make it do it's work.
     CFRunLoopSourceSignal(RootObject::performJavaScriptSource());
     if (CFRunLoopIsWaiting(RootObject::runLoop())) {
         CFRunLoopWakeUp(RootObject::runLoop());
     }

     // Wait until the JavaScript access thread is done.
     CFRunLoopRun ();

     CFRunLoopRemoveSource(currentRunLoop, completionSource, kCFRunLoopDefaultMode);
     CFRelease (completionSource);

     unlockJavaScriptAccess();
 }

 static void performJavaScriptAccess(void*)
 {
     assert (CFRunLoopGetCurrent() == RootObject::runLoop());

     // Dispatch JavaScript calls here.
     CFRunLoopSourceContext sourceContext;
     CFRunLoopSourceGetContext (completionSource, &sourceContext);
     JSObjectCallContext *callContext = (JSObjectCallContext *)sourceContext.info;
     CFRunLoopRef originatingLoop = callContext->originatingLoop;

     JavaJSObject::invoke (callContext);

     // Signal the originating thread that we're done.
     CFRunLoopSourceSignal (completionSource);
     if (CFRunLoopIsWaiting(originatingLoop)) {
         CFRunLoopWakeUp(originatingLoop);
     }
 }

 FindRootObjectForNativeHandleFunctionPtr RootObject::_findRootObjectForNativeHandleFunctionPtr = 0;
 CFRunLoopRef RootObject::_runLoop = 0;
 CFRunLoopSourceRef RootObject::_performJavaScriptSource = 0;

 // Must be called from the thread that will be used to access JavaScript.
 void RootObject::setFindRootObjectForNativeHandleFunction(FindRootObjectForNativeHandleFunctionPtr aFunc) {
     // Should only be called once.
     assert (_findRootObjectForNativeHandleFunctionPtr == 0);

     _findRootObjectForNativeHandleFunctionPtr = aFunc;

     // Assume that we can retain this run loop forever.  It'll most
     // likely (always?) be the main loop.
     _runLoop = (CFRunLoopRef)CFRetain (CFRunLoopGetCurrent ());

     // Setup a source the other threads can use to signal the _runLoop
     // thread that a JavaScript call needs to be invoked.
     CFRunLoopSourceContext sourceContext = {0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, performJavaScriptAccess};
     RootObject::_performJavaScriptSource = CFRunLoopSourceCreate(NULL, 0, &sourceContext);
     CFRunLoopAddSource(RootObject::_runLoop, RootObject::_performJavaScriptSource, kCFRunLoopDefaultMode);
 }
 #endif

 // Destroys the RootObject and unprotects all JSObjects associated with it.
 void RootObject::destroy()
 {
     ReferencesSet* referencesSet = getReferencesSet(this);

     if (referencesSet) {
         ReferencesSet::iterator end = referencesSet->end();
         for (ReferencesSet::iterator it = referencesSet->begin(); it != end; ++it) {
             JSLock lock;
             gcUnprotect(it->first);
         }
         referencesSet->clear();
         ReferencesByRootMap* refsByRoot = getReferencesByRootMap();
         refsByRoot->remove(this);
         delete referencesSet;
     }

     delete this;
 }

 } } // namespace KJS::Bindings
	/*
	* Copyright (C) 2004 Apple Computer, Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/
	#include "config.h"

	#include "object.h"
	#include "runtime_root.h"
	#include <wtf/HashCountedSet.h>

	namespace KJS { namespace Bindings {

	// Java does NOT always call finalize (and thus KJS_JSObject_JSFinalize) when
	// it collects an objects. This presents some difficulties. We must ensure
	// the a JavaJSObject's corresponding JavaScript object doesn't get collected. We
	// do this by incrementing the JavaScript's reference count the first time we
	// create a JavaJSObject for it, and decrementing the JavaScript reference count when
	// the last JavaJSObject that refers to it is finalized, or when the applet is
	// shutdown.
	//
	// To do this we keep a map that maps each applet instance
	// to the JavaScript objects it is referencing. For each JavaScript instance
	// we also maintain a secondary reference count. When that reference count reaches
	// 1 OR the applet is shutdown we deref the JavaScript instance. Applet instances
	// are represented by a jlong.

	typedef HashMap<const RootObject, ReferencesSet> ReferencesByRootMap;

	static ReferencesByRootMap* getReferencesByRootMap()
	{
	static ReferencesByRootMap* referencesByRootMap = 0;

	if (!referencesByRootMap)
	referencesByRootMap = new ReferencesByRootMap;

	return referencesByRootMap;
	}

	static ReferencesSet* getReferencesSet(const RootObject* rootObject)
	{
	ReferencesByRootMap* refsByRoot = getReferencesByRootMap();
	ReferencesSet* referencesSet = 0;

	referencesSet = refsByRoot->get(rootObject);
	if (!referencesSet) {
	referencesSet = new ReferencesSet;
	refsByRoot->add(rootObject, referencesSet);
	}
	return referencesSet;
	}

	// Scan all the dictionary for all the roots to see if any have a
	// reference to the imp, and if so, return it's reference count
	// dictionary.
	// FIXME: This is a potential performance bottleneck with many applets. We could fix be adding a
	// imp to root dictionary.
	ReferencesSet* findReferenceSet(JSObject* imp)
	{
	ReferencesByRootMap* refsByRoot = getReferencesByRootMap ();
	if (refsByRoot) {
	ReferencesByRootMap::const_iterator end = refsByRoot->end();
	for (ReferencesByRootMap::const_iterator it = refsByRoot->begin(); it != end; ++it) {
	ReferencesSet* set = it->second;

	if (set->contains(imp))
	return set;
	}
	}

	return 0;
	}

	// FIXME: This is a potential performance bottleneck with many applets. We could fix be adding a
	// imp to root dictionary.
	const RootObject* rootObjectForImp (JSObject* imp)
	{
	ReferencesByRootMap* refsByRoot = getReferencesByRootMap ();
	const RootObject* rootObject = 0;

	if (refsByRoot) {
	ReferencesByRootMap::const_iterator end = refsByRoot->end();
	for (ReferencesByRootMap::const_iterator it = refsByRoot->begin(); it != end; ++it) {
	ReferencesSet* set = it->second;
	if (set->contains(imp)) {
	rootObject = it->first;
	break;
	}
	}
	}

	return rootObject;
	}

	const RootObject* rootObjectForInterpreter(Interpreter* interpreter)
	{
	ReferencesByRootMap* refsByRoot = getReferencesByRootMap ();

	if (refsByRoot) {
	ReferencesByRootMap::const_iterator end = refsByRoot->end();
	for (ReferencesByRootMap::const_iterator it = refsByRoot->begin(); it != end; ++it) {
	const RootObject* aRootObject = it->first;

	if (aRootObject->interpreter() == interpreter)
	return aRootObject;
	}
	}

	return 0;
	}

	void addNativeReference(const RootObject* rootObject, JSObject* imp)
	{
	if (rootObject) {
	ReferencesSet* referenceMap = getReferencesSet(rootObject);

	unsigned numReferences = referenceMap->count(imp);
	if (numReferences == 0) {
	JSLock lock;
	gcProtect(imp);
	}
	referenceMap->add(imp);
	}
	}

	void removeNativeReference(JSObject* imp)
	{
	if (!imp)
	return;

	ReferencesSet *referencesSet = findReferenceSet(imp);
	if (referencesSet) {
	unsigned numReferences = referencesSet->count(imp);

	if (numReferences == 1) {
	JSLock lock;
	gcUnprotect(imp);
	}
	referencesSet->remove(imp);
	}
	}

	#if PLATFORM(MAC)
	// May only be set by dispatchToJavaScriptThread().
	static CFRunLoopSourceRef completionSource;

	static void completedJavaScriptAccess (void *i)
	{
	assert (CFRunLoopGetCurrent() != RootObject::runLoop());

	JSObjectCallContext callContext = (JSObjectCallContext )i;
	CFRunLoopRef runLoop = (CFRunLoopRef)callContext->originatingLoop;

	assert (CFRunLoopGetCurrent() == runLoop);

	CFRunLoopStop(runLoop);
	}

	static pthread_once_t javaScriptAccessLockOnce = PTHREAD_ONCE_INIT;
	static pthread_mutex_t javaScriptAccessLock;
	static int javaScriptAccessLockCount = 0;

	static void initializeJavaScriptAccessLock()
	{
	pthread_mutexattr_t attr;

	pthread_mutexattr_init(&attr);
	pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);

	pthread_mutex_init(&javaScriptAccessLock, &attr);
	}

	static inline void lockJavaScriptAccess()
	{
	// Perhaps add deadlock detection?
	pthread_once(&javaScriptAccessLockOnce, initializeJavaScriptAccessLock);
	pthread_mutex_lock(&javaScriptAccessLock);
	javaScriptAccessLockCount++;
	}

	static inline void unlockJavaScriptAccess()
	{
	javaScriptAccessLockCount--;
	pthread_mutex_unlock(&javaScriptAccessLock);
	}


	void RootObject::dispatchToJavaScriptThread(JSObjectCallContext *context)
	{
	// This lock guarantees that only one thread can invoke
	// at a time, and also guarantees that completionSource;
	// won't get clobbered.
	lockJavaScriptAccess();

	CFRunLoopRef currentRunLoop = CFRunLoopGetCurrent();

	assert (currentRunLoop != RootObject::runLoop());

	// Setup a source to signal once the invocation of the JavaScript
	// call completes.
	//
	// FIXME: This could be a potential performance issue. Creating and
	// adding run loop sources is expensive. We could create one source
	// per thread, as needed, instead.
	context->originatingLoop = currentRunLoop;
	CFRunLoopSourceContext sourceContext = {0, context, NULL, NULL, NULL, NULL, NULL, NULL, NULL, completedJavaScriptAccess};
	completionSource = CFRunLoopSourceCreate(NULL, 0, &sourceContext);
	CFRunLoopAddSource(currentRunLoop, completionSource, kCFRunLoopDefaultMode);

	// Wakeup JavaScript access thread and make it do it's work.
	CFRunLoopSourceSignal(RootObject::performJavaScriptSource());
	if (CFRunLoopIsWaiting(RootObject::runLoop())) {
	CFRunLoopWakeUp(RootObject::runLoop());
	}

	// Wait until the JavaScript access thread is done.
	CFRunLoopRun ();

	CFRunLoopRemoveSource(currentRunLoop, completionSource, kCFRunLoopDefaultMode);
	CFRelease (completionSource);

	unlockJavaScriptAccess();
	}

	static void performJavaScriptAccess(void*)
	{
	assert (CFRunLoopGetCurrent() == RootObject::runLoop());

	// Dispatch JavaScript calls here.
	CFRunLoopSourceContext sourceContext;
	CFRunLoopSourceGetContext (completionSource, &sourceContext);
	JSObjectCallContext callContext = (JSObjectCallContext )sourceContext.info;
	CFRunLoopRef originatingLoop = callContext->originatingLoop;

	JavaJSObject::invoke (callContext);

	// Signal the originating thread that we're done.
	CFRunLoopSourceSignal (completionSource);
	if (CFRunLoopIsWaiting(originatingLoop)) {
	CFRunLoopWakeUp(originatingLoop);
	}
	}

	FindRootObjectForNativeHandleFunctionPtr RootObject::_findRootObjectForNativeHandleFunctionPtr = 0;
	CFRunLoopRef RootObject::_runLoop = 0;
	CFRunLoopSourceRef RootObject::_performJavaScriptSource = 0;

	// Must be called from the thread that will be used to access JavaScript.
	void RootObject::setFindRootObjectForNativeHandleFunction(FindRootObjectForNativeHandleFunctionPtr aFunc) {
	// Should only be called once.
	assert (_findRootObjectForNativeHandleFunctionPtr == 0);

	_findRootObjectForNativeHandleFunctionPtr = aFunc;

	// Assume that we can retain this run loop forever. It'll most
	// likely (always?) be the main loop.
	_runLoop = (CFRunLoopRef)CFRetain (CFRunLoopGetCurrent ());

	// Setup a source the other threads can use to signal the _runLoop
	// thread that a JavaScript call needs to be invoked.
	CFRunLoopSourceContext sourceContext = {0, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, performJavaScriptAccess};
	RootObject::_performJavaScriptSource = CFRunLoopSourceCreate(NULL, 0, &sourceContext);
	CFRunLoopAddSource(RootObject::_runLoop, RootObject::_performJavaScriptSource, kCFRunLoopDefaultMode);
	}
	#endif

	// Destroys the RootObject and unprotects all JSObjects associated with it.
	void RootObject::destroy()
	{
	ReferencesSet* referencesSet = getReferencesSet(this);

	if (referencesSet) {
	ReferencesSet::iterator end = referencesSet->end();
	for (ReferencesSet::iterator it = referencesSet->begin(); it != end; ++it) {
	JSLock lock;
	gcUnprotect(it->first);
	}
	referencesSet->clear();
	ReferencesByRootMap* refsByRoot = getReferencesByRootMap();
	refsByRoot->remove(this);
	delete referencesSet;
	}

	delete this;
	}

	} } // namespace KJS::Bindings