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      1 /*
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      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
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     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 V8Utilities_h
     32 #define V8Utilities_h
     33 
     34 #include <wtf/Forward.h>
     35 #include <v8.h>
     36 
     37 namespace WebCore {
     38 
     39     class EventListener;
     40     class Frame;
     41     class KURL;
     42     class ScriptExecutionContext;
     43     class ScriptState;
     44 
     45     // Use an array to hold dependents. It works like a ref-counted scheme. A value can be added more than once to the DOM object.
     46     void createHiddenDependency(v8::Handle<v8::Object>, v8::Local<v8::Value>, int cacheIndex);
     47     void removeHiddenDependency(v8::Handle<v8::Object>, v8::Local<v8::Value>, int cacheIndex);
     48 
     49     // Combo create/remove, for generated event-handler-setter bindings:
     50     void transferHiddenDependency(v8::Handle<v8::Object>, EventListener* oldValue, v8::Local<v8::Value> newValue, int cacheIndex);
     51 
     52     bool processingUserGesture();
     53     bool shouldAllowNavigation(Frame*);
     54     KURL completeURL(const String& relativeURL);
     55 
     56     ScriptExecutionContext* getScriptExecutionContext();
     57 
     58     void throwTypeMismatchException();
     59 
     60     enum CallbackAllowedValueFlag {
     61         CallbackAllowUndefined = 1,
     62         CallbackAllowNull = 1 << 1
     63     };
     64 
     65     typedef unsigned CallbackAllowedValueFlags;
     66 
     67     // 'FunctionOnly' is assumed for the created callback.
     68     template <typename V8CallbackType>
     69     PassRefPtr<V8CallbackType> createFunctionOnlyCallback(v8::Local<v8::Value> value, bool& succeeded, CallbackAllowedValueFlags acceptedValues = 0)
     70     {
     71         succeeded = true;
     72 
     73         if (value->IsUndefined() && (acceptedValues & CallbackAllowUndefined))
     74             return 0;
     75 
     76         if (value->IsNull() && (acceptedValues & CallbackAllowNull))
     77             return 0;
     78 
     79         if (!value->IsFunction()) {
     80             succeeded = false;
     81             throwTypeMismatchException();
     82             return 0;
     83         }
     84 
     85         return V8CallbackType::create(value, getScriptExecutionContext());
     86     }
     87 
     88     class AllowAllocation {
     89     public:
     90         inline AllowAllocation()
     91         {
     92             m_previous = m_current;
     93             m_current = true;
     94         }
     95 
     96         inline ~AllowAllocation()
     97         {
     98             m_current = m_previous;
     99         }
    100 
    101         static bool m_current;
    102 
    103     private:
    104         bool m_previous;
    105     };
    106 
    107     class SafeAllocation {
    108      public:
    109       static inline v8::Local<v8::Object> newInstance(v8::Handle<v8::Function>);
    110       static inline v8::Local<v8::Object> newInstance(v8::Handle<v8::ObjectTemplate>);
    111       static inline v8::Local<v8::Object> newInstance(v8::Handle<v8::Function>, int argc, v8::Handle<v8::Value> argv[]);
    112     };
    113 
    114     v8::Local<v8::Object> SafeAllocation::newInstance(v8::Handle<v8::Function> function)
    115     {
    116         if (function.IsEmpty())
    117             return v8::Local<v8::Object>();
    118         AllowAllocation allow;
    119         return function->NewInstance();
    120     }
    121 
    122     v8::Local<v8::Object> SafeAllocation::newInstance(v8::Handle<v8::ObjectTemplate> objectTemplate)
    123     {
    124         if (objectTemplate.IsEmpty())
    125             return v8::Local<v8::Object>();
    126         AllowAllocation allow;
    127         return objectTemplate->NewInstance();
    128     }
    129 
    130     v8::Local<v8::Object> SafeAllocation::newInstance(v8::Handle<v8::Function> function, int argc, v8::Handle<v8::Value> argv[])
    131     {
    132         if (function.IsEmpty())
    133             return v8::Local<v8::Object>();
    134         AllowAllocation allow;
    135         return function->NewInstance(argc, argv);
    136     }
    137 
    138 } // namespace WebCore
    139 
    140 #endif // V8Utilities_h
    141