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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef WorkerFileWriterCallbacksBridge_h
#define WorkerFileWriterCallbacksBridge_h
#if ENABLE(FILE_SYSTEM)
#include "WebFileError.h"
#include "WebFileWriterClient.h"
#include "WorkerContext.h"
#include <wtf/PassOwnPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/ThreadSafeRefCounted.h>
namespace WebCore {
class AsyncFileWriterClient;
class KURL;
class WorkerLoaderProxy;
}
namespace WTF {
class String;
}
using WTF::String;
namespace WebKit {
class WebFileSystem;
class WebFileWriter;
class WebFileWriterClient;
class WebWorkerBase;
// This class is used as a mechanism to bridge calls between threads.
// Calls to a WebFileWriter must happen on the main thread, but they come from
// the context thread. The responses through the WebFileWriterClient interface
// start on the main thread, but must be sent via the worker context thread.
//
// A typical flow for write would look like this:
// Bridge::postWriteToMainThread() on WorkerThread
// --> Bridge::writeOnMainThread() is called on MainThread
// --> WebFileWriter::write()
// This makes an IPC; the actual operation is down in the browser.
// --> Bridge::didWrite is called on MainThread
// --> Bridge::didWriteOnWorkerThread is called on WorkerThread
// This calls the original client (m_clientOnWorkerThread).
//
// The bridge object is refcounted, so that it doesn't get deleted while there
// are cross-thread calls in flight. Each CrossThreadTask carries a reference
// to the bridge, which guarantees that the bridge will still be valid when the
// task is executed. In order to shut down the bridge, the WebFileWriterClient
// should call postShutdownToMainThread before dropping its reference to the
// bridge. This ensures that the WebFileWriter will be cleared on the main
// thread and that no further calls to the WebFileWriterClient will be made.
class WorkerFileWriterCallbacksBridge : public ThreadSafeRefCounted<WorkerFileWriterCallbacksBridge>, public WebCore::WorkerContext::Observer, public WebFileWriterClient {
public:
~WorkerFileWriterCallbacksBridge();
// WorkerContext::Observer method.
virtual void notifyStop();
static PassRefPtr<WorkerFileWriterCallbacksBridge> create(const String& path, WebCore::WorkerLoaderProxy* proxy, WebCore::ScriptExecutionContext* workerContext, WebCore::AsyncFileWriterClient* client)
{
return adoptRef(new WorkerFileWriterCallbacksBridge(path, proxy, workerContext, client));
}
// Methods that create an instance and post an initial request task to the main thread. They must be called on the worker thread.
void postWriteToMainThread(long long position, const WebCore::KURL& data);
void postTruncateToMainThread(long long length);
void postAbortToMainThread();
// The owning WorkerAsyncFileWriterChromium should call this method before dropping its last reference to the bridge, on the context thread.
// The actual deletion of the WorkerFileWriterCallbacksBridge may happen on either the main or context thread, depending on where the last reference goes away; that's safe as long as this is called first.
void postShutdownToMainThread(PassRefPtr<WorkerFileWriterCallbacksBridge>);
// Callback methods that are called on the main thread.
// These are the implementation of WebKit::WebFileWriterClient.
void didWrite(long long bytes, bool complete);
void didFail(WebFileError);
void didTruncate();
// Call this on the context thread to wait for the current operation to complete.
bool waitForOperationToComplete();
private:
WorkerFileWriterCallbacksBridge(const String& path, WebCore::WorkerLoaderProxy*, WebCore::ScriptExecutionContext*, WebCore::AsyncFileWriterClient*);
void postInitToMainThread(const String& path);
// Methods that are to be called on the main thread.
static void writeOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long position, const WebCore::KURL& data);
static void truncateOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long length);
static void abortOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>);
static void initOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, const String& path);
static void shutdownOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>);
// Methods that dispatch to AsyncFileWriterClient on the worker threads.
static void didWriteOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, long long length, bool complete);
static void didFailOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, WebFileError);
static void didTruncateOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>);
// Called on the main thread to run the supplied task.
static void runTaskOnMainThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, PassOwnPtr<WebCore::ScriptExecutionContext::Task>);
// Called on the worker thread to run the supplied task.
static void runTaskOnWorkerThread(WebCore::ScriptExecutionContext*, PassRefPtr<WorkerFileWriterCallbacksBridge>, PassOwnPtr<WebCore::ScriptExecutionContext::Task>);
// Called on the worker thread to dispatch to the main thread.
void dispatchTaskToMainThread(PassOwnPtr<WebCore::ScriptExecutionContext::Task>);
// Called on the main thread to dispatch to the worker thread.
void dispatchTaskToWorkerThread(PassOwnPtr<WebCore::ScriptExecutionContext::Task>);
// Used from the main thread to post tasks to the context thread.
WebCore::WorkerLoaderProxy* m_proxy;
// Used on the context thread, only to check that we're running on the context thread.
WebCore::ScriptExecutionContext* m_workerContext;
// Created and destroyed from the main thread.
OwnPtr<WebKit::WebFileWriter> m_writer;
// Used on the context thread to call back into the client.
WebCore::AsyncFileWriterClient* m_clientOnWorkerThread;
// Used to indicate that shutdown has started on the main thread, and hence the writer has been deleted.
bool m_writerDeleted;
// Used by waitForOperationToComplete.
bool m_operationInProgress;
// Used by postTaskForModeToWorkerContext and runInMode.
String m_mode;
};
} // namespace WebCore
#endif
#endif // WorkerFileWriterCallbacksBridge_h