components/drive/file_system/truncate_operation.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 "components/drive/file_system/truncate_operation.h"
   6
   7 #include "base/bind.h"
   8 #include "base/callback_helpers.h"
   9 #include "base/files/file.h"
  10 #include "base/files/file_path.h"
  11 #include "base/logging.h"
  12 #include "base/sequenced_task_runner.h"
  13 #include "base/task_runner_util.h"
  14 #include "base/thread_task_runner_handle.h"
  15 #include "components/drive/drive.pb.h"
  16 #include "components/drive/file_cache.h"
  17 #include "components/drive/file_errors.h"
  18 #include "components/drive/file_system/download_operation.h"
  19 #include "components/drive/file_system/operation_delegate.h"
  20 #include "components/drive/job_scheduler.h"
  21
  22 namespace drive {
  23 namespace file_system {
  24 namespace {
  25
  26 // Truncates the local file at |local_cache_path| to the |length| bytes,
  27 // then marks the resource is dirty on |cache|.
  28 FileError TruncateOnBlockingPool(internal::ResourceMetadata* metadata,
  29                                  internal::FileCache* cache,
  30                                  const std::string& local_id,
  31                                  const base::FilePath& local_cache_path,
  32                                  int64 length) {
  33   DCHECK(metadata);
  34   DCHECK(cache);
  35
  36   scoped_ptr<base::ScopedClosureRunner> file_closer;
  37   FileError error = cache->OpenForWrite(local_id, &file_closer);
  38   if (error != FILE_ERROR_OK)
  39     return error;
  40
  41   base::File file(local_cache_path,
  42                   base::File::FLAG_OPEN | base::File::FLAG_WRITE);
  43   if (!file.IsValid())
  44     return FILE_ERROR_FAILED;
  45
  46   if (!file.SetLength(length))
  47     return FILE_ERROR_FAILED;
  48
  49   return FILE_ERROR_OK;
  50 }
  51
  52 }  // namespace
  53
  54 TruncateOperation::TruncateOperation(
  55     base::SequencedTaskRunner* blocking_task_runner,
  56     OperationDelegate* delegate,
  57     JobScheduler* scheduler,
  58     internal::ResourceMetadata* metadata,
  59     internal::FileCache* cache,
  60     const base::FilePath& temporary_file_directory)
  61     : blocking_task_runner_(blocking_task_runner),
  62       delegate_(delegate),
  63       metadata_(metadata),
  64       cache_(cache),
  65       download_operation_(new DownloadOperation(blocking_task_runner,
  66                                                 delegate,
  67                                                 scheduler,
  68                                                 metadata,
  69                                                 cache,
  70                                                 temporary_file_directory)),
  71       weak_ptr_factory_(this) {
  72 }
  73
  74 TruncateOperation::~TruncateOperation() {
  75 }
  76
  77 void TruncateOperation::Truncate(const base::FilePath& file_path,
  78                                  int64 length,
  79                                  const FileOperationCallback& callback) {
  80   DCHECK(thread_checker_.CalledOnValidThread());
  81   DCHECK(!callback.is_null());
  82
  83   if (length < 0) {
  84     base::ThreadTaskRunnerHandle::Get()->PostTask(
  85         FROM_HERE,
  86         base::Bind(callback, FILE_ERROR_INVALID_OPERATION));
  87     return;
  88   }
  89
  90   // TODO(kinaba): http://crbug.com/132780.
  91   // Optimize the cases for small |length|, at least for |length| == 0.
  92   download_operation_->EnsureFileDownloadedByPath(
  93       file_path,
  94       ClientContext(USER_INITIATED),
  95       GetFileContentInitializedCallback(),
  96       google_apis::GetContentCallback(),
  97       base::Bind(&TruncateOperation::TruncateAfterEnsureFileDownloadedByPath,
  98                  weak_ptr_factory_.GetWeakPtr(), length, callback));
  99 }
 100
 101 void TruncateOperation::TruncateAfterEnsureFileDownloadedByPath(
 102     int64 length,
 103     const FileOperationCallback& callback,
 104     FileError error,
 105     const base::FilePath& local_file_path,
 106     scoped_ptr<ResourceEntry> entry) {
 107   DCHECK(thread_checker_.CalledOnValidThread());
 108   DCHECK(!callback.is_null());
 109
 110   if (error != FILE_ERROR_OK) {
 111     callback.Run(error);
 112     return;
 113   }
 114   DCHECK(entry);
 115   DCHECK(entry->has_file_specific_info());
 116
 117   if (entry->file_specific_info().is_hosted_document()) {
 118     callback.Run(FILE_ERROR_INVALID_OPERATION);
 119     return;
 120   }
 121
 122   base::PostTaskAndReplyWithResult(
 123       blocking_task_runner_.get(),
 124       FROM_HERE,
 125       base::Bind(&TruncateOnBlockingPool,
 126                  metadata_, cache_, entry->local_id(), local_file_path, length),
 127       base::Bind(
 128           &TruncateOperation::TruncateAfterTruncateOnBlockingPool,
 129           weak_ptr_factory_.GetWeakPtr(), entry->local_id(), callback));
 130 }
 131
 132 void TruncateOperation::TruncateAfterTruncateOnBlockingPool(
 133     const std::string& local_id,
 134     const FileOperationCallback& callback,
 135     FileError error) {
 136   DCHECK(thread_checker_.CalledOnValidThread());
 137   DCHECK(!callback.is_null());
 138
 139   delegate_->OnEntryUpdatedByOperation(ClientContext(USER_INITIATED), local_id);
 140
 141   callback.Run(error);
 142 }
 143
 144 }  // namespace file_system
 145 }  // namespace drive