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      1 /*
      2  * Copyright (C) 2008, 2009, 2011 Google 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 are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef ScriptState_h
     32 #define ScriptState_h
     33 
     34 #include "DOMWrapperWorld.h"
     35 #include <v8.h>
     36 #include <wtf/Noncopyable.h>
     37 #include <wtf/RefCounted.h>
     38 
     39 namespace WebCore {
     40 class DOMWrapperWorld;
     41 class Frame;
     42 class Node;
     43 class Page;
     44 class WorkerContext;
     45 
     46 class ScriptState {
     47     WTF_MAKE_NONCOPYABLE(ScriptState);
     48 public:
     49     bool hadException() { return !m_exception.IsEmpty(); }
     50     void setException(v8::Local<v8::Value> exception)
     51     {
     52         m_exception = exception;
     53     }
     54     v8::Local<v8::Value> exception() { return m_exception; }
     55 
     56     v8::Local<v8::Context> context() const
     57     {
     58         return v8::Local<v8::Context>::New(m_context);
     59     }
     60 
     61     static ScriptState* forContext(v8::Local<v8::Context>);
     62     static ScriptState* current();
     63 
     64 protected:
     65     ScriptState() { }
     66     ~ScriptState();
     67 
     68 private:
     69     friend ScriptState* mainWorldScriptState(Frame*);
     70     explicit ScriptState(v8::Handle<v8::Context>);
     71 
     72     static void weakReferenceCallback(v8::Persistent<v8::Value> object, void* parameter);
     73 
     74     v8::Local<v8::Value> m_exception;
     75     v8::Persistent<v8::Context> m_context;
     76 };
     77 
     78 class EmptyScriptState : public ScriptState {
     79 public:
     80     EmptyScriptState() : ScriptState() { }
     81     ~EmptyScriptState() { }
     82 };
     83 
     84 class ScriptStateProtectedPtr {
     85     WTF_MAKE_NONCOPYABLE(ScriptStateProtectedPtr);
     86 public:
     87     ScriptStateProtectedPtr() : m_scriptState(0) { }
     88     ScriptStateProtectedPtr(ScriptState* scriptState) : m_scriptState(scriptState)
     89     {
     90         v8::HandleScope handleScope;
     91         // Keep the context from being GC'ed. ScriptState is guaranteed to be live while the context is live.
     92         m_context = v8::Persistent<v8::Context>::New(scriptState->context());
     93     }
     94     ~ScriptStateProtectedPtr()
     95     {
     96         if (!m_context.IsEmpty()) {
     97             m_context.Dispose();
     98             m_context.Clear();
     99         }
    100     }
    101     ScriptState* get() const { return m_scriptState; }
    102 private:
    103     ScriptState* m_scriptState;
    104     v8::Persistent<v8::Context> m_context;
    105 };
    106 
    107 ScriptState* mainWorldScriptState(Frame*);
    108 
    109 ScriptState* scriptStateFromNode(DOMWrapperWorld*, Node*);
    110 ScriptState* scriptStateFromPage(DOMWrapperWorld*, Page*);
    111 
    112 #if ENABLE(WORKERS)
    113 ScriptState* scriptStateFromWorkerContext(WorkerContext*);
    114 #endif
    115 
    116 inline DOMWrapperWorld* debuggerWorld() { return mainThreadNormalWorld(); }
    117 inline DOMWrapperWorld* pluginWorld() { return mainThreadNormalWorld(); }
    118 
    119 }
    120 
    121 #endif // ScriptState_h
    122