storage/browser/fileapi/file_system_file_stream_reader.cc

   1 // Copyright (c) 2012 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 "storage/browser/fileapi/file_system_file_stream_reader.h"
   6
   7 #include "base/files/file_util_proxy.h"
   8 #include "base/single_thread_task_runner.h"
   9 #include "net/base/file_stream.h"
  10 #include "net/base/io_buffer.h"
  11 #include "net/base/net_errors.h"
  12 #include "storage/browser/fileapi/file_system_context.h"
  13 #include "storage/browser/fileapi/file_system_operation_runner.h"
  14
  15 using storage::FileStreamReader;
  16
  17 // TODO(kinuko): Remove this temporary namespace hack after we move both
  18 // blob and fileapi into content namespace.
  19 namespace storage {
  20
  21 FileStreamReader* FileStreamReader::CreateForFileSystemFile(
  22     storage::FileSystemContext* file_system_context,
  23     const storage::FileSystemURL& url,
  24     int64 initial_offset,
  25     const base::Time& expected_modification_time) {
  26   return new storage::FileSystemFileStreamReader(
  27       file_system_context, url, initial_offset, expected_modification_time);
  28 }
  29
  30 }  // namespace storage
  31
  32 namespace storage {
  33
  34 namespace {
  35
  36 void ReadAdapter(base::WeakPtr<FileSystemFileStreamReader> reader,
  37                  net::IOBuffer* buf, int buf_len,
  38                  const net::CompletionCallback& callback) {
  39   if (!reader.get())
  40     return;
  41   int rv = reader->Read(buf, buf_len, callback);
  42   if (rv != net::ERR_IO_PENDING)
  43     callback.Run(rv);
  44 }
  45
  46 void GetLengthAdapter(base::WeakPtr<FileSystemFileStreamReader> reader,
  47                       const net::Int64CompletionCallback& callback) {
  48   if (!reader.get())
  49     return;
  50   int rv = reader->GetLength(callback);
  51   if (rv != net::ERR_IO_PENDING)
  52     callback.Run(rv);
  53 }
  54
  55 void Int64CallbackAdapter(const net::Int64CompletionCallback& callback,
  56                           int value) {
  57   callback.Run(value);
  58 }
  59
  60 }  // namespace
  61
  62 FileSystemFileStreamReader::~FileSystemFileStreamReader() {
  63 }
  64
  65 int FileSystemFileStreamReader::Read(
  66     net::IOBuffer* buf, int buf_len,
  67     const net::CompletionCallback& callback) {
  68   if (local_file_reader_)
  69     return local_file_reader_->Read(buf, buf_len, callback);
  70   return CreateSnapshot(
  71       base::Bind(&ReadAdapter, weak_factory_.GetWeakPtr(),
  72                  make_scoped_refptr(buf), buf_len, callback),
  73       callback);
  74 }
  75
  76 int64 FileSystemFileStreamReader::GetLength(
  77     const net::Int64CompletionCallback& callback) {
  78   if (local_file_reader_)
  79     return local_file_reader_->GetLength(callback);
  80   return CreateSnapshot(
  81       base::Bind(&GetLengthAdapter, weak_factory_.GetWeakPtr(), callback),
  82       base::Bind(&Int64CallbackAdapter, callback));
  83 }
  84
  85 FileSystemFileStreamReader::FileSystemFileStreamReader(
  86     FileSystemContext* file_system_context,
  87     const FileSystemURL& url,
  88     int64 initial_offset,
  89     const base::Time& expected_modification_time)
  90     : file_system_context_(file_system_context),
  91       url_(url),
  92       initial_offset_(initial_offset),
  93       expected_modification_time_(expected_modification_time),
  94       has_pending_create_snapshot_(false),
  95       weak_factory_(this) {
  96 }
  97
  98 int FileSystemFileStreamReader::CreateSnapshot(
  99     const base::Closure& callback,
 100     const net::CompletionCallback& error_callback) {
 101   DCHECK(!has_pending_create_snapshot_);
 102   has_pending_create_snapshot_ = true;
 103   file_system_context_->operation_runner()->CreateSnapshotFile(
 104       url_,
 105       base::Bind(&FileSystemFileStreamReader::DidCreateSnapshot,
 106                  weak_factory_.GetWeakPtr(),
 107                  callback,
 108                  error_callback));
 109   return net::ERR_IO_PENDING;
 110 }
 111
 112 void FileSystemFileStreamReader::DidCreateSnapshot(
 113     const base::Closure& callback,
 114     const net::CompletionCallback& error_callback,
 115     base::File::Error file_error,
 116     const base::File::Info& file_info,
 117     const base::FilePath& platform_path,
 118     const scoped_refptr<storage::ShareableFileReference>& file_ref) {
 119   DCHECK(has_pending_create_snapshot_);
 120   DCHECK(!local_file_reader_.get());
 121   has_pending_create_snapshot_ = false;
 122
 123   if (file_error != base::File::FILE_OK) {
 124     error_callback.Run(net::FileErrorToNetError(file_error));
 125     return;
 126   }
 127
 128   // Keep the reference (if it's non-null) so that the file won't go away.
 129   snapshot_ref_ = file_ref;
 130
 131   local_file_reader_.reset(
 132       FileStreamReader::CreateForLocalFile(
 133           file_system_context_->default_file_task_runner(),
 134           platform_path, initial_offset_, expected_modification_time_));
 135
 136   callback.Run();
 137 }
 138
 139 }  // namespace storage