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      1 /*
      2  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #include "config.h"
     27 #include "JSContextRef.h"
     28 #include "JSContextRefPrivate.h"
     29 
     30 #include "APICast.h"
     31 #include "InitializeThreading.h"
     32 #include "JSCallbackObject.h"
     33 #include "JSClassRef.h"
     34 #include "JSGlobalObject.h"
     35 #include "JSObject.h"
     36 #include <wtf/text/StringHash.h>
     37 
     38 #if OS(DARWIN)
     39 #include <mach-o/dyld.h>
     40 
     41 static const int32_t webkitFirstVersionWithConcurrentGlobalContexts = 0x2100500; // 528.5.0
     42 #endif
     43 
     44 using namespace JSC;
     45 
     46 JSContextGroupRef JSContextGroupCreate()
     47 {
     48     initializeThreading();
     49     return toRef(JSGlobalData::createContextGroup(ThreadStackTypeSmall).leakRef());
     50 }
     51 
     52 JSContextGroupRef JSContextGroupRetain(JSContextGroupRef group)
     53 {
     54     toJS(group)->ref();
     55     return group;
     56 }
     57 
     58 void JSContextGroupRelease(JSContextGroupRef group)
     59 {
     60     toJS(group)->deref();
     61 }
     62 
     63 JSGlobalContextRef JSGlobalContextCreate(JSClassRef globalObjectClass)
     64 {
     65     initializeThreading();
     66 #if OS(DARWIN)
     67     // When running on Tiger or Leopard, or if the application was linked before JSGlobalContextCreate was changed
     68     // to use a unique JSGlobalData, we use a shared one for compatibility.
     69 #if !defined(BUILDING_ON_TIGER) && !defined(BUILDING_ON_LEOPARD)
     70     if (NSVersionOfLinkTimeLibrary("JavaScriptCore") <= webkitFirstVersionWithConcurrentGlobalContexts) {
     71 #else
     72     {
     73 #endif
     74         JSLock lock(LockForReal);
     75         return JSGlobalContextCreateInGroup(toRef(&JSGlobalData::sharedInstance()), globalObjectClass);
     76     }
     77 #endif // OS(DARWIN)
     78 
     79     return JSGlobalContextCreateInGroup(0, globalObjectClass);
     80 }
     81 
     82 JSGlobalContextRef JSGlobalContextCreateInGroup(JSContextGroupRef group, JSClassRef globalObjectClass)
     83 {
     84     initializeThreading();
     85 
     86     JSLock lock(LockForReal);
     87     RefPtr<JSGlobalData> globalData = group ? PassRefPtr<JSGlobalData>(toJS(group)) : JSGlobalData::createContextGroup(ThreadStackTypeSmall);
     88 
     89     APIEntryShim entryShim(globalData.get(), false);
     90 
     91 #if ENABLE(JSC_MULTIPLE_THREADS)
     92     globalData->makeUsableFromMultipleThreads();
     93 #endif
     94 
     95     if (!globalObjectClass) {
     96         JSGlobalObject* globalObject = new (globalData.get()) JSGlobalObject(*globalData);
     97         return JSGlobalContextRetain(toGlobalRef(globalObject->globalExec()));
     98     }
     99 
    100     JSGlobalObject* globalObject = new (globalData.get()) JSCallbackObject<JSGlobalObject>(*globalData, globalObjectClass, JSCallbackObject<JSGlobalObject>::createStructure(*globalData, jsNull()));
    101     ExecState* exec = globalObject->globalExec();
    102     JSValue prototype = globalObjectClass->prototype(exec);
    103     if (!prototype)
    104         prototype = jsNull();
    105     globalObject->resetPrototype(*globalData, prototype);
    106     return JSGlobalContextRetain(toGlobalRef(exec));
    107 }
    108 
    109 JSGlobalContextRef JSGlobalContextRetain(JSGlobalContextRef ctx)
    110 {
    111     ExecState* exec = toJS(ctx);
    112     APIEntryShim entryShim(exec);
    113 
    114     JSGlobalData& globalData = exec->globalData();
    115     gcProtect(exec->dynamicGlobalObject());
    116     globalData.ref();
    117     return ctx;
    118 }
    119 
    120 void JSGlobalContextRelease(JSGlobalContextRef ctx)
    121 {
    122     ExecState* exec = toJS(ctx);
    123     JSLock lock(exec);
    124 
    125     JSGlobalData& globalData = exec->globalData();
    126     JSGlobalObject* dgo = exec->dynamicGlobalObject();
    127     IdentifierTable* savedIdentifierTable = wtfThreadData().setCurrentIdentifierTable(globalData.identifierTable);
    128 
    129     // One reference is held by JSGlobalObject, another added by JSGlobalContextRetain().
    130     bool releasingContextGroup = globalData.refCount() == 2;
    131     bool releasingGlobalObject = Heap::heap(dgo)->unprotect(dgo);
    132     // If this is the last reference to a global data, it should also
    133     // be the only remaining reference to the global object too!
    134     ASSERT(!releasingContextGroup || releasingGlobalObject);
    135 
    136     // An API 'JSGlobalContextRef' retains two things - a global object and a
    137     // global data (or context group, in API terminology).
    138     // * If this is the last reference to any contexts in the given context group,
    139     //   call destroy on the heap (the global data is being  freed).
    140     // * If this was the last reference to the global object, then unprotecting
    141     //   it may  release a lot of GC memory - run the garbage collector now.
    142     // * If there are more references remaining the the global object, then do nothing
    143     //   (specifically that is more protects, which we assume come from other JSGlobalContextRefs).
    144     if (releasingContextGroup) {
    145         globalData.clearBuiltinStructures();
    146         globalData.heap.destroy();
    147     } else if (releasingGlobalObject)
    148         globalData.heap.collectAllGarbage();
    149 
    150     globalData.deref();
    151 
    152     wtfThreadData().setCurrentIdentifierTable(savedIdentifierTable);
    153 }
    154 
    155 JSObjectRef JSContextGetGlobalObject(JSContextRef ctx)
    156 {
    157     ExecState* exec = toJS(ctx);
    158     APIEntryShim entryShim(exec);
    159 
    160     // It is necessary to call toThisObject to get the wrapper object when used with WebCore.
    161     return toRef(exec->lexicalGlobalObject()->toThisObject(exec));
    162 }
    163 
    164 JSContextGroupRef JSContextGetGroup(JSContextRef ctx)
    165 {
    166     ExecState* exec = toJS(ctx);
    167     return toRef(&exec->globalData());
    168 }
    169 
    170 JSGlobalContextRef JSContextGetGlobalContext(JSContextRef ctx)
    171 {
    172     ExecState* exec = toJS(ctx);
    173     APIEntryShim entryShim(exec);
    174 
    175     return toGlobalRef(exec->lexicalGlobalObject()->globalExec());
    176 }
    177