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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/platform_file.h"
      9 #include "base/synchronization/waitable_event.h"
     10 #include "content/child/child_thread.h"
     11 #include "content/child/fileapi/file_system_dispatcher.h"
     12 #include "webkit/child/worker_task_runner.h"
     13 
     14 using webkit_glue::WorkerTaskRunner;
     15 
     16 namespace content {
     17 
     18 namespace {
     19 
     20 FileSystemDispatcher* GetFileSystemDispatcher() {
     21   return ChildThread::current() ?
     22       ChildThread::current()->file_system_dispatcher() : NULL;
     23 }
     24 
     25 }  // namespace
     26 
     27 typedef FileSystemDispatcher::StatusCallback StatusCallback;
     28 typedef FileSystemDispatcher::WriteCallback WriteCallback;
     29 
     30 // This instance may be created outside main thread but runs mainly
     31 // on main thread.
     32 class WebFileWriterImpl::WriterBridge
     33     : public base::RefCountedThreadSafe<WriterBridge> {
     34  public:
     35   WriterBridge(WebFileWriterImpl::Type type)
     36       : request_id_(0),
     37         thread_id_(WorkerTaskRunner::Instance()->CurrentWorkerId()),
     38         written_bytes_(0) {
     39     if (type == WebFileWriterImpl::TYPE_SYNC)
     40       waitable_event_.reset(new base::WaitableEvent(false, false));
     41   }
     42 
     43   void Truncate(const GURL& path, int64 offset,
     44                 const StatusCallback& status_callback) {
     45     status_callback_ = status_callback;
     46     if (!GetFileSystemDispatcher())
     47       return;
     48     ChildThread::current()->file_system_dispatcher()->Truncate(
     49         path, offset, &request_id_,
     50         base::Bind(&WriterBridge::DidFinish, this));
     51   }
     52 
     53   void Write(const GURL& path, const std::string& id, int64 offset,
     54              const WriteCallback& write_callback,
     55              const StatusCallback& error_callback) {
     56     write_callback_ = write_callback;
     57     status_callback_ = error_callback;
     58     if (!GetFileSystemDispatcher())
     59       return;
     60     ChildThread::current()->file_system_dispatcher()->Write(
     61         path, id, offset, &request_id_,
     62         base::Bind(&WriterBridge::DidWrite, this),
     63         base::Bind(&WriterBridge::DidFinish, this));
     64   }
     65 
     66   void Cancel(const StatusCallback& status_callback) {
     67     status_callback_ = status_callback;
     68     if (!GetFileSystemDispatcher())
     69       return;
     70     ChildThread::current()->file_system_dispatcher()->Cancel(
     71         request_id_,
     72         base::Bind(&WriterBridge::DidFinish, this));
     73   }
     74 
     75   base::WaitableEvent* waitable_event() {
     76     return waitable_event_.get();
     77   }
     78 
     79   void WaitAndRun() {
     80     waitable_event_->Wait();
     81     DCHECK(!results_closure_.is_null());
     82     results_closure_.Run();
     83   }
     84 
     85  private:
     86   friend class base::RefCountedThreadSafe<WriterBridge>;
     87   virtual ~WriterBridge() {}
     88 
     89   void DidWrite(int64 bytes, bool complete) {
     90     written_bytes_ += bytes;
     91     if (waitable_event_ && !complete)
     92       return;
     93     PostTaskToWorker(base::Bind(write_callback_, written_bytes_, complete));
     94   }
     95 
     96   void DidFinish(base::PlatformFileError status) {
     97     PostTaskToWorker(base::Bind(status_callback_, status));
     98   }
     99 
    100   void PostTaskToWorker(const base::Closure& closure) {
    101     written_bytes_ = 0;
    102     if (!thread_id_) {
    103       DCHECK(!waitable_event_);
    104       closure.Run();
    105       return;
    106     }
    107     if (waitable_event_) {
    108       results_closure_ = closure;
    109       waitable_event_->Signal();
    110       return;
    111     }
    112     WorkerTaskRunner::Instance()->PostTask(thread_id_, closure);
    113   }
    114 
    115   StatusCallback status_callback_;
    116   WriteCallback write_callback_;
    117   int request_id_;
    118   int thread_id_;
    119   int written_bytes_;
    120   scoped_ptr<base::WaitableEvent> waitable_event_;
    121   base::Closure results_closure_;
    122 };
    123 
    124 WebFileWriterImpl::WebFileWriterImpl(
    125      const GURL& path, blink::WebFileWriterClient* client,
    126      Type type,
    127      base::MessageLoopProxy* main_thread_loop)
    128   : WebFileWriterBase(path, client),
    129     main_thread_loop_(main_thread_loop),
    130     bridge_(new WriterBridge(type)) {
    131 }
    132 
    133 WebFileWriterImpl::~WebFileWriterImpl() {
    134 }
    135 
    136 void WebFileWriterImpl::DoTruncate(const GURL& path, int64 offset) {
    137   RunOnMainThread(base::Bind(&WriterBridge::Truncate, bridge_,
    138       path, offset,
    139       base::Bind(&WebFileWriterImpl::DidFinish, AsWeakPtr())));
    140 }
    141 
    142 void WebFileWriterImpl::DoWrite(
    143     const GURL& path, const std::string& blob_id, int64 offset) {
    144   RunOnMainThread(base::Bind(&WriterBridge::Write, bridge_,
    145       path, blob_id, offset,
    146       base::Bind(&WebFileWriterImpl::DidWrite, AsWeakPtr()),
    147       base::Bind(&WebFileWriterImpl::DidFinish, AsWeakPtr())));
    148 }
    149 
    150 void WebFileWriterImpl::DoCancel() {
    151   RunOnMainThread(base::Bind(&WriterBridge::Cancel, bridge_,
    152       base::Bind(&WebFileWriterImpl::DidFinish, AsWeakPtr())));
    153 }
    154 
    155 void WebFileWriterImpl::RunOnMainThread(const base::Closure& closure) {
    156   if (main_thread_loop_->RunsTasksOnCurrentThread()) {
    157     DCHECK(!bridge_->waitable_event());
    158     closure.Run();
    159     return;
    160   }
    161   main_thread_loop_->PostTask(FROM_HERE, closure);
    162   if (bridge_->waitable_event())
    163     bridge_->WaitAndRun();
    164 }
    165 
    166 }  // namespace content
    167