flutter_flutter/engine/bindings/core/v8/V8PerContextData.cpp

/*
 * Copyright (C) 2012 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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#include "config.h"
#include "bindings/core/v8/V8PerContextData.h"

#include "bindings/core/v8/ScriptState.h"
#include "bindings/core/v8/V8Binding.h"
#include "bindings/core/v8/V8ObjectConstructor.h"
#include "wtf/StringExtras.h"

#include <stdlib.h>

namespace blink {

V8PerContextData::V8PerContextData(v8::Handle<v8::Context> context)
    : m_isolate(context->GetIsolate())
    , m_wrapperBoilerplates(m_isolate)
    , m_constructorMap(m_isolate)
    , m_contextHolder(adoptPtr(new gin::ContextHolder(m_isolate)))
    , m_context(m_isolate, context)
    , m_customElementBindings(adoptPtr(new CustomElementBindingMap()))
{
    m_contextHolder->SetContext(context);

    v8::Context::Scope contextScope(context);
    ASSERT(m_errorPrototype.isEmpty());
    v8::Handle<v8::Object> object = v8::Handle<v8::Object>::Cast(context->Global()->Get(v8AtomicString(m_isolate, "Error")));
    ASSERT(!object.IsEmpty());
    v8::Handle<v8::Value> prototypeValue = object->Get(v8AtomicString(m_isolate, "prototype"));
    ASSERT(!prototypeValue.IsEmpty());
    m_errorPrototype.set(m_isolate, prototypeValue);
}

V8PerContextData::~V8PerContextData()
{
}

PassOwnPtr<V8PerContextData> V8PerContextData::create(v8::Handle<v8::Context> context)
{
    return adoptPtr(new V8PerContextData(context));
}

V8PerContextData* V8PerContextData::from(v8::Handle<v8::Context> context)
{
    return ScriptState::from(context)->perContextData();
}

v8::Local<v8::Object> V8PerContextData::createWrapperFromCacheSlowCase(const WrapperTypeInfo* type)
{
    ASSERT(!m_errorPrototype.isEmpty());

    v8::Context::Scope scope(context());
    v8::Local<v8::Function> function = constructorForType(type);
    v8::Local<v8::Object> instanceTemplate = V8ObjectConstructor::newInstance(m_isolate, function);
    if (!instanceTemplate.IsEmpty()) {
        m_wrapperBoilerplates.Set(type, instanceTemplate);
        return instanceTemplate->Clone();
    }
    return v8::Local<v8::Object>();
}

v8::Local<v8::Function> V8PerContextData::constructorForTypeSlowCase(const WrapperTypeInfo* type)
{
    ASSERT(!m_errorPrototype.isEmpty());

    v8::Context::Scope scope(context());
    v8::Handle<v8::FunctionTemplate> functionTemplate = type->domTemplate(m_isolate);
    // Getting the function might fail if we're running out of stack or memory.
    v8::TryCatch tryCatch;
    v8::Local<v8::Function> function = functionTemplate->GetFunction();
    if (function.IsEmpty())
        return v8::Local<v8::Function>();

    if (type->parentClass) {
        v8::Local<v8::Object> prototypeTemplate = constructorForType(type->parentClass);
        if (prototypeTemplate.IsEmpty())
            return v8::Local<v8::Function>();
        function->SetPrototype(prototypeTemplate);
    }

    v8::Local<v8::Value> prototypeValue = function->Get(v8AtomicString(m_isolate, "prototype"));
    if (!prototypeValue.IsEmpty() && prototypeValue->IsObject()) {
        v8::Local<v8::Object> prototypeObject = v8::Local<v8::Object>::Cast(prototypeValue);
        if (prototypeObject->InternalFieldCount() == v8PrototypeInternalFieldcount
            && type->wrapperTypePrototype == WrapperTypeInfo::WrapperTypeObjectPrototype)
            prototypeObject->SetAlignedPointerInInternalField(v8PrototypeTypeIndex, const_cast<WrapperTypeInfo*>(type));
        type->installConditionallyEnabledMethods(prototypeObject, m_isolate);
        if (type->wrapperTypePrototype == WrapperTypeInfo::WrapperTypeExceptionPrototype)
            prototypeObject->SetPrototype(m_errorPrototype.newLocal(m_isolate));
    }

    m_constructorMap.Set(type, function);

    return function;
}

v8::Local<v8::Object> V8PerContextData::prototypeForType(const WrapperTypeInfo* type)
{
    v8::Local<v8::Object> constructor = constructorForType(type);
    if (constructor.IsEmpty())
        return v8::Local<v8::Object>();
    return constructor->Get(v8String(m_isolate, "prototype")).As<v8::Object>();
}

void V8PerContextData::addCustomElementBinding(CustomElementDefinition* definition, PassOwnPtr<CustomElementBinding> binding)
{
    ASSERT(!m_customElementBindings->contains(definition));
    m_customElementBindings->add(definition, binding);
}

void V8PerContextData::clearCustomElementBinding(CustomElementDefinition* definition)
{
    CustomElementBindingMap::iterator it = m_customElementBindings->find(definition);
    ASSERT_WITH_SECURITY_IMPLICATION(it != m_customElementBindings->end());
    m_customElementBindings->remove(it);
}

CustomElementBinding* V8PerContextData::customElementBinding(CustomElementDefinition* definition)
{
    CustomElementBindingMap::const_iterator it = m_customElementBindings->find(definition);
    ASSERT_WITH_SECURITY_IMPLICATION(it != m_customElementBindings->end());
    return it->value.get();
}


static v8::Handle<v8::Value> createDebugData(const char* worldName, int debugId, v8::Isolate* isolate)
{
    char buffer[32];
    unsigned wanted;
    if (debugId == -1)
        wanted = snprintf(buffer, sizeof(buffer), "%s", worldName);
    else
        wanted = snprintf(buffer, sizeof(buffer), "%s,%d", worldName, debugId);

    if (wanted < sizeof(buffer))
        return v8AtomicString(isolate, buffer);

    return v8::Undefined(isolate);
}

static v8::Handle<v8::Value> debugData(v8::Handle<v8::Context> context)
{
    v8::Context::Scope contextScope(context);
    return context->GetEmbedderData(v8ContextDebugIdIndex);
}

static void setDebugData(v8::Handle<v8::Context> context, v8::Handle<v8::Value> value)
{
    v8::Context::Scope contextScope(context);
    context->SetEmbedderData(v8ContextDebugIdIndex, value);
}

bool V8PerContextDebugData::setContextDebugData(v8::Handle<v8::Context> context, const char* worldName, int debugId)
{
    if (!debugData(context)->IsUndefined())
        return false;
    v8::HandleScope scope(context->GetIsolate());
    v8::Handle<v8::Value> debugData = createDebugData(worldName, debugId, context->GetIsolate());
    setDebugData(context, debugData);
    return true;
}

int V8PerContextDebugData::contextDebugId(v8::Handle<v8::Context> context)
{
    v8::HandleScope scope(context->GetIsolate());
    v8::Handle<v8::Value> data = debugData(context);

    if (!data->IsString())
        return -1;
    v8::String::Utf8Value utf8(data);
    char* comma = strnstr(*utf8, ",", utf8.length());
    if (!comma)
        return -1;
    return atoi(comma + 1);
}

} // namespace blink