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
41static const int32_t webkitFirstVersionWithConcurrentGlobalContexts = 0x2100500; // 528.5.0
42#endif
43
44using namespace JSC;
45
46JSContextGroupRef JSContextGroupCreate()
47{
48    initializeThreading();
49    return toRef(JSGlobalData::createContextGroup(ThreadStackTypeSmall).leakRef());
50}
51
52JSContextGroupRef JSContextGroupRetain(JSContextGroupRef group)
53{
54    toJS(group)->ref();
55    return group;
56}
57
58void JSContextGroupRelease(JSContextGroupRef group)
59{
60    toJS(group)->deref();
61}
62
63JSGlobalContextRef 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
82JSGlobalContextRef 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
109JSGlobalContextRef 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
120void 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
155JSObjectRef 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
164JSContextGroupRef JSContextGetGroup(JSContextRef ctx)
165{
166    ExecState* exec = toJS(ctx);
167    return toRef(&exec->globalData());
168}
169
170JSGlobalContextRef JSContextGetGlobalContext(JSContextRef ctx)
171{
172    ExecState* exec = toJS(ctx);
173    APIEntryShim entryShim(exec);
174
175    return toGlobalRef(exec->lexicalGlobalObject()->globalExec());
176}
177