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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "content/child/fileapi/webfilewriter_impl.h"
      6 
      7 #include "base/bind.h"
      8 #include "base/synchronization/waitable_event.h"
      9 #include "content/child/child_thread.h"
     10 #include "content/child/fileapi/file_system_dispatcher.h"
     11 #include "content/child/worker_task_runner.h"
     12 
     13 namespace content {
     14 
     15 namespace {
     16 
     17 FileSystemDispatcher* GetFileSystemDispatcher() {
     18   return ChildThread::current() ?
     19       ChildThread::current()->file_system_dispatcher() : NULL;
     20 }
     21 
     22 }  // namespace
     23 
     24 typedef FileSystemDispatcher::StatusCallback StatusCallback;
     25 typedef FileSystemDispatcher::WriteCallback WriteCallback;
     26 
     27 // This instance may be created outside main thread but runs mainly
     28 // on main thread.
     29 class WebFileWriterImpl::WriterBridge
     30     : public base::RefCountedThreadSafe<WriterBridge> {
     31  public:
     32   WriterBridge(WebFileWriterImpl::Type type)
     33       : request_id_(0),
     34         thread_id_(WorkerTaskRunner::Instance()->CurrentWorkerId()),
     35         written_bytes_(0) {
     36     if (type == WebFileWriterImpl::TYPE_SYNC)
     37       waitable_event_.reset(new base::WaitableEvent(false, false));
     38   }
     39 
     40   void Truncate(const GURL& path, int64 offset,
     41                 const StatusCallback& status_callback) {
     42     status_callback_ = status_callback;
     43     if (!GetFileSystemDispatcher())
     44       return;
     45     ChildThread::current()->file_system_dispatcher()->Truncate(
     46         path, offset, &request_id_,
     47         base::Bind(&WriterBridge::DidFinish, this));
     48   }
     49 
     50   void Write(const GURL& path, const std::string& id, int64 offset,
     51              const WriteCallback& write_callback,
     52              const StatusCallback& error_callback) {
     53     write_callback_ = write_callback;
     54     status_callback_ = error_callback;
     55     if (!GetFileSystemDispatcher())
     56       return;
     57     ChildThread::current()->file_system_dispatcher()->Write(
     58         path, id, offset, &request_id_,
     59         base::Bind(&WriterBridge::DidWrite, this),
     60         base::Bind(&WriterBridge::DidFinish, this));
     61   }
     62 
     63   void Cancel(const StatusCallback& status_callback) {
     64     status_callback_ = status_callback;
     65     if (!GetFileSystemDispatcher())
     66       return;
     67     ChildThread::current()->file_system_dispatcher()->Cancel(
     68         request_id_,
     69         base::Bind(&WriterBridge::DidFinish, this));
     70   }
     71 
     72   base::WaitableEvent* waitable_event() {
     73     return waitable_event_.get();
     74   }
     75 
     76   void WaitAndRun() {
     77     waitable_event_->Wait();
     78     DCHECK(!results_closure_.is_null());
     79     results_closure_.Run();
     80   }
     81 
     82  private:
     83   friend class base::RefCountedThreadSafe<WriterBridge>;
     84   virtual ~WriterBridge() {}
     85 
     86   void DidWrite(int64 bytes, bool complete) {
     87     written_bytes_ += bytes;
     88     if (waitable_event_ && !complete)
     89       return;
     90     PostTaskToWorker(base::Bind(write_callback_, written_bytes_, complete));
     91   }
     92 
     93   void DidFinish(base::File::Error status) {
     94     PostTaskToWorker(base::Bind(status_callback_, status));
     95   }
     96 
     97   void PostTaskToWorker(const base::Closure& closure) {
     98     written_bytes_ = 0;
     99     if (!thread_id_) {
    100       DCHECK(!waitable_event_);
    101       closure.Run();
    102       return;
    103     }
    104     if (waitable_event_) {
    105       results_closure_ = closure;
    106       waitable_event_->Signal();
    107       return;
    108     }
    109     WorkerTaskRunner::Instance()->PostTask(thread_id_, closure);
    110   }
    111 
    112   StatusCallback status_callback_;
    113   WriteCallback write_callback_;
    114   int request_id_;
    115   int thread_id_;
    116   int written_bytes_;
    117   scoped_ptr<base::WaitableEvent> waitable_event_;
    118   base::Closure results_closure_;
    119 };
    120 
    121 WebFileWriterImpl::WebFileWriterImpl(
    122      const GURL& path, blink::WebFileWriterClient* client,
    123      Type type,
    124      base::MessageLoopProxy* main_thread_loop)
    125   : WebFileWriterBase(path, client),
    126     main_thread_loop_(main_thread_loop),
    127     bridge_(new WriterBridge(type)) {
    128 }
    129 
    130 WebFileWriterImpl::~WebFileWriterImpl() {
    131 }
    132 
    133 void WebFileWriterImpl::DoTruncate(const GURL& path, int64 offset) {
    134   RunOnMainThread(base::Bind(&WriterBridge::Truncate, bridge_,
    135       path, offset,
    136       base::Bind(&WebFileWriterImpl::DidFinish, AsWeakPtr())));
    137 }
    138 
    139 void WebFileWriterImpl::DoWrite(
    140     const GURL& path, const std::string& blob_id, int64 offset) {
    141   RunOnMainThread(base::Bind(&WriterBridge::Write, bridge_,
    142       path, blob_id, offset,
    143       base::Bind(&WebFileWriterImpl::DidWrite, AsWeakPtr()),
    144       base::Bind(&WebFileWriterImpl::DidFinish, AsWeakPtr())));
    145 }
    146 
    147 void WebFileWriterImpl::DoCancel() {
    148   RunOnMainThread(base::Bind(&WriterBridge::Cancel, bridge_,
    149       base::Bind(&WebFileWriterImpl::DidFinish, AsWeakPtr())));
    150 }
    151 
    152 void WebFileWriterImpl::RunOnMainThread(const base::Closure& closure) {
    153   if (main_thread_loop_->RunsTasksOnCurrentThread()) {
    154     DCHECK(!bridge_->waitable_event());
    155     closure.Run();
    156     return;
    157   }
    158   main_thread_loop_->PostTask(FROM_HERE, closure);
    159   if (bridge_->waitable_event())
    160     bridge_->WaitAndRun();
    161 }
    162 
    163 }  // namespace content
    164