content/child/fileapi/webfilewriter_impl.cc

   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