/*

 * Copyright (C) 2006, 2007 Apple 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 "JSContextRef.h"

#include "JSContextRefPrivate.h"

#include "APICast.h"

#include "InitializeThreading.h"

#include "JSCallbackObject.h"

#include "JSClassRef.h"

#include "JSGlobalObject.h"

#include "JSObject.h"

#include <wtf/text/StringHash.h>

#if OS(DARWIN)

#include <mach-o/dyld.h>

static const int32_t webkitFirstVersionWithConcurrentGlobalContexts = 0x2100500; // 528.5.0

#endif

using namespace JSC;

JSContextGroupRef JSContextGroupCreate()

{

    initializeThreading();

    return toRef(JSGlobalData::createContextGroup(ThreadStackTypeSmall).releaseRef());

}

JSContextGroupRef JSContextGroupRetain(JSContextGroupRef group)

{

    toJS(group)->ref();

    return group;

}

void JSContextGroupRelease(JSContextGroupRef group)

{

    toJS(group)->deref();

}

JSGlobalContextRef JSGlobalContextCreate(JSClassRef globalObjectClass)

{

    initializeThreading();

#if OS(DARWIN)

    // When running on Tiger or Leopard, or if the application was linked before JSGlobalContextCreate was changed

    // to use a unique JSGlobalData, we use a shared one for compatibility.

#if !defined(BUILDING_ON_TIGER) && !defined(BUILDING_ON_LEOPARD)

    if (NSVersionOfLinkTimeLibrary("JavaScriptCore") <= webkitFirstVersionWithConcurrentGlobalContexts) {

#else

    {

#endif

        JSLock lock(LockForReal);

        return JSGlobalContextCreateInGroup(toRef(&JSGlobalData::sharedInstance()), globalObjectClass);

    }

#endif // OS(DARWIN)

    return JSGlobalContextCreateInGroup(0, globalObjectClass);

}

JSGlobalContextRef JSGlobalContextCreateInGroup(JSContextGroupRef group, JSClassRef globalObjectClass)

{

    initializeThreading();

    JSLock lock(LockForReal);

    RefPtr<JSGlobalData> globalData = group ? PassRefPtr<JSGlobalData>(toJS(group)) : JSGlobalData::createContextGroup(ThreadStackTypeSmall);

    APIEntryShim entryShim(globalData.get(), false);

#if ENABLE(JSC_MULTIPLE_THREADS)

    globalData->makeUsableFromMultipleThreads();

#endif

    if (!globalObjectClass) {

        JSGlobalObject* globalObject = new (globalData.get()) JSGlobalObject;

        return JSGlobalContextRetain(toGlobalRef(globalObject->globalExec()));

    }

    JSGlobalObject* globalObject = new (globalData.get()) JSCallbackObject<JSGlobalObject>(globalObjectClass, JSCallbackObject<JSGlobalObject>::createStructure(jsNull()));

    ExecState* exec = globalObject->globalExec();

    JSValue prototype = globalObjectClass->prototype(exec);

    if (!prototype)

        prototype = jsNull();

    globalObject->resetPrototype(prototype);

    return JSGlobalContextRetain(toGlobalRef(exec));

}

JSGlobalContextRef JSGlobalContextRetain(JSGlobalContextRef ctx)

{

    ExecState* exec = toJS(ctx);

    APIEntryShim entryShim(exec);

    JSGlobalData& globalData = exec->globalData();

    gcProtect(exec->dynamicGlobalObject());

    globalData.ref();

    return ctx;

}

void JSGlobalContextRelease(JSGlobalContextRef ctx)

{

    ExecState* exec = toJS(ctx);

    JSLock lock(exec);

    JSGlobalData& globalData = exec->globalData();

    JSGlobalObject* dgo = exec->dynamicGlobalObject();

    IdentifierTable* savedIdentifierTable = wtfThreadData().setCurrentIdentifierTable(globalData.identifierTable);

    // One reference is held by JSGlobalObject, another added by JSGlobalContextRetain().

    bool releasingContextGroup = globalData.refCount() == 2;

    bool releasingGlobalObject = Heap::heap(dgo)->unprotect(dgo);

    // If this is the last reference to a global data, it should also

    // be the only remaining reference to the global object too!

    ASSERT(!releasingContextGroup || releasingGlobalObject);

    // An API 'JSGlobalContextRef' retains two things - a global object and a

    // global data (or context group, in API terminology).

    // * If this is the last reference to any contexts in the given context group,

    //   call destroy on the heap (the global data is being  freed).

    // * If this was the last reference to the global object, then unprotecting

    //   it may  release a lot of GC memory - run the garbage collector now.

    // * If there are more references remaining the the global object, then do nothing

    //   (specifically that is more protects, which we assume come from other JSGlobalContextRefs).

    if (releasingContextGroup)

        globalData.heap.destroy();

    else if (releasingGlobalObject)

        globalData.heap.collectAllGarbage();

    globalData.deref();

    wtfThreadData().setCurrentIdentifierTable(savedIdentifierTable);

}

JSObjectRef JSContextGetGlobalObject(JSContextRef ctx)

{

    ExecState* exec = toJS(ctx);

    APIEntryShim entryShim(exec);

    // It is necessary to call toThisObject to get the wrapper object when used with WebCore.

    return toRef(exec->lexicalGlobalObject()->toThisObject(exec));

}

JSContextGroupRef JSContextGetGroup(JSContextRef ctx)

{

    ExecState* exec = toJS(ctx);

    return toRef(&exec->globalData());

}

JSGlobalContextRef JSContextGetGlobalContext(JSContextRef ctx)

{

    ExecState* exec = toJS(ctx);

    APIEntryShim entryShim(exec);

    return toGlobalRef(exec->lexicalGlobalObject()->globalExec());

}