API/JSContextRef.cpp

   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).releaseRef());
  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;
  97         return JSGlobalContextRetain(toGlobalRef(globalObject->globalExec()));
  98     }
  99
 100     JSGlobalObject* globalObject = new (globalData.get()) JSCallbackObject<JSGlobalObject>(globalObjectClass);
 101     ExecState* exec = globalObject->globalExec();
 102     JSValue prototype = globalObjectClass->prototype(exec);
 103     if (!prototype)
 104         prototype = jsNull();
 105     globalObject->resetPrototype(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.heap.destroy();
 146     else if (releasingGlobalObject)
 147         globalData.heap.collectAllGarbage();
 148
 149     globalData.deref();
 150
 151     wtfThreadData().setCurrentIdentifierTable(savedIdentifierTable);
 152 }
 153
 154 JSObjectRef JSContextGetGlobalObject(JSContextRef ctx)
 155 {
 156     ExecState* exec = toJS(ctx);
 157     APIEntryShim entryShim(exec);
 158
 159     // It is necessary to call toThisObject to get the wrapper object when used with WebCore.
 160     return toRef(exec->lexicalGlobalObject()->toThisObject(exec));
 161 }
 162
 163 JSContextGroupRef JSContextGetGroup(JSContextRef ctx)
 164 {
 165     ExecState* exec = toJS(ctx);
 166     return toRef(&exec->globalData());
 167 }
 168
 169 JSGlobalContextRef JSContextGetGlobalContext(JSContextRef ctx)
 170 {
 171     ExecState* exec = toJS(ctx);
 172     APIEntryShim entryShim(exec);
 173
 174     return toGlobalRef(exec->lexicalGlobalObject()->globalExec());
 175 }