fileapi: FileWriter and LocalFileWriter.

webkit/fileapi/local_file_writer.cc

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "webkit/fileapi/local_file_writer.h"
+
+#include "base/callback.h"
+#include "base/location.h"
+#include "net/base/file_stream.h"
+#include "net/base/io_buffer.h"
+
+namespace fileapi {
+
+namespace {
+
+const int kOpenFlagsForWrite = base::PLATFORM_FILE_OPEN |
+                               base::PLATFORM_FILE_WRITE |
+                               base::PLATFORM_FILE_ASYNC;
+
+void EmptyCompletionCallback(int) {}
+
+}  // anonymous namespace

[kinuko, 2012/04/20 11:26:37]

nit: just 'namespace' would be ok (and more common)

[kinaba, 2012/04/23 08:56:41]

Done.

+
+LocalFileWriter::LocalFileWriter(const FilePath& file_path)
+    : weak_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(this)),
+      file_path_(file_path),
+      has_pending_operation_(false) {}
+
+LocalFileWriter::~LocalFileWriter() {
+  DCHECK(!has_pending_operation_);
+  DCHECK(cancel_callback_.is_null());
+
+  weak_factory_.InvalidateWeakPtrs();
+}
+
+int LocalFileWriter::Write(net::IOBuffer* buf, int buf_len,
+                           const net::CompletionCallback& callback) {
+  DCHECK(!has_pending_operation_);
+  DCHECK(cancel_callback_.is_null());
+
+  has_pending_operation_ = true;
+  if (stream_impl_.get()) {
+    int result = InitiateWrite(buf, buf_len, callback);
+    if (result != net::ERR_IO_PENDING)
+      has_pending_operation_ = false;
+    return result;
+  }
+  return InitiateOpen(base::Bind(&LocalFileWriter::ReadyToWrite,
+                                 weak_factory_.GetWeakPtr(),
+                                 make_scoped_refptr(buf), buf_len, callback));
+}
+
+int LocalFileWriter::Seek(int64 offset,
+                          const net::Int64CompletionCallback& callback) {
+  DCHECK(!has_pending_operation_);
+  DCHECK(cancel_callback_.is_null());
+
+  has_pending_operation_ = true;
+  if (stream_impl_.get()) {
+    int result = InitiateSeek(offset, callback);
+    if (result != net::ERR_IO_PENDING)
+      has_pending_operation_ = false;
+    return result;
+  }
+  return InitiateOpen(base::Bind(&LocalFileWriter::ReadyToSeek,
+                                 weak_factory_.GetWeakPtr(), offset, callback));
+}
+
+void LocalFileWriter::Cancel(const net::CompletionCallback& callback) {
+  DCHECK(has_pending_operation_);

[kinuko, 2012/04/20 11:26:37]

Could we simply run the callback (asynchronously) when we have no pending
operations?
Then the caller could call Cancel() at any time and could do the final cleanup
in its callback (e.g. delete the instance etc).

[kinaba, 2012/04/23 08:56:41]

I agree. Done.

+  DCHECK(cancel_callback_.is_null());
+
+  DCHECK(!callback.is_null());
+  cancel_callback_ = callback;
+}
+
+int LocalFileWriter::InitiateOpen(
+    const net::CompletionCallback& main_operation) {
+  DCHECK(has_pending_operation_);
+  DCHECK(!stream_impl_.get());
+
+  stream_impl_.reset(new net::FileStream(NULL));
+  return stream_impl_->Open(file_path_, kOpenFlagsForWrite,
+                            base::Bind(&LocalFileWriter::DidOpen,
+                                       weak_factory_.GetWeakPtr(),
+                                       main_operation));
+}
+
+void LocalFileWriter::DidOpen(const net::CompletionCallback& main_operation,
+                              int result) {
+  DCHECK(has_pending_operation_);
+  DCHECK(stream_impl_.get());
+
+  if (result != net::OK)
+    stream_impl_.reset(NULL);
+  if (CancelIfRequested())
+    return;
+  main_operation.Run(result);
+}
+
+void LocalFileWriter::ReadyToWrite(net::IOBuffer* buf, int buf_len,
+                                   const net::CompletionCallback& callback,
+                                   int file_open_result) {
+  DCHECK(has_pending_operation_);
+
+  if (file_open_result != net::OK) {
+    has_pending_operation_ = false;
+    callback.Run(file_open_result);
+    return;
+  }
+
+  int result = InitiateWrite(buf, buf_len, callback);
+  if (result != net::ERR_IO_PENDING) {
+    has_pending_operation_ = false;
+    callback.Run(result);
+  }
+}
+
+void LocalFileWriter::ReadyToSeek(int64 offset,
+                                  const net::Int64CompletionCallback& callback,
+                                  int file_open_result) {
+  DCHECK(has_pending_operation_);
+
+  if (file_open_result != net::OK) {
+    has_pending_operation_ = false;
+    callback.Run(file_open_result);
+    return;
+  }
+
+  int result = InitiateSeek(offset, callback);
+  if (result != net::ERR_IO_PENDING) {
+    has_pending_operation_ = false;
+    callback.Run(result);
+  }
+}
+
+int LocalFileWriter::InitiateWrite(net::IOBuffer* buf, int buf_len,
+                                   const net::CompletionCallback& callback) {
+  DCHECK(has_pending_operation_);
+  DCHECK(stream_impl_.get());
+
+  return stream_impl_->Write(buf, buf_len,
+                             base::Bind(&LocalFileWriter::DidWrite,
+                                        weak_factory_.GetWeakPtr(),
+                                        callback));
+}
+
+int LocalFileWriter::InitiateSeek(
+    int64 offset, const net::Int64CompletionCallback& callback) {
+  DCHECK(has_pending_operation_);
+  DCHECK(stream_impl_.get());
+
+  return stream_impl_->Seek(net::FROM_BEGIN, offset,
+                            base::Bind(&LocalFileWriter::DidSeek,
+                                       weak_factory_.GetWeakPtr(),
+                                       callback));
+}
+
+void LocalFileWriter::DidWrite(const net::CompletionCallback& callback,
+                               int result) {
+  DCHECK(has_pending_operation_);
+
+  if (CancelIfRequested())
+    return;
+  has_pending_operation_ = false;
+  callback.Run(result);
+}
+
+void LocalFileWriter::DidSeek(const net::Int64CompletionCallback& callback,
+                              int64 result) {
+  DCHECK(has_pending_operation_);
+
+  if (CancelIfRequested())
+    return;
+  has_pending_operation_ = false;
+  callback.Run(result);
+}
+
+bool LocalFileWriter::CancelIfRequested() {
+  DCHECK(has_pending_operation_);
+
+  if (cancel_callback_.is_null())
+    return false;
+
+  net::CompletionCallback pending_cancel = cancel_callback_;
+  has_pending_operation_ = false;
+  cancel_callback_.Reset();
+  pending_cancel.Run(net::OK);
+  return true;
+}
+
+}  // namespace fileapi