net/disk_cache/file_posix.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 "net/disk_cache/file.h"
   6
   7 #include <fcntl.h>
   8
   9 #include "base/bind.h"
  10 #include "base/location.h"
  11 #include "base/logging.h"
  12 #include "base/threading/worker_pool.h"
  13 #include "net/base/net_errors.h"
  14 #include "net/disk_cache/disk_cache.h"
  15 #include "net/disk_cache/in_flight_io.h"
  16
  17 namespace {
  18
  19 // This class represents a single asynchronous IO operation while it is being
  20 // bounced between threads.
  21 class FileBackgroundIO : public disk_cache::BackgroundIO {
  22  public:
  23   // Other than the actual parameters for the IO operation (including the
  24   // |callback| that must be notified at the end), we need the controller that
  25   // is keeping track of all operations. When done, we notify the controller
  26   // (we do NOT invoke the callback), in the worker thead that completed the
  27   // operation.
  28   FileBackgroundIO(disk_cache::File* file, const void* buf, size_t buf_len,
  29                    size_t offset, disk_cache::FileIOCallback* callback,
  30                    disk_cache::InFlightIO* controller)
  31       : disk_cache::BackgroundIO(controller), callback_(callback), file_(file),
  32         buf_(buf), buf_len_(buf_len), offset_(offset) {
  33   }
  34
  35   disk_cache::FileIOCallback* callback() {
  36     return callback_;
  37   }
  38
  39   disk_cache::File* file() {
  40     return file_;
  41   }
  42
  43   // Read and Write are the operations that can be performed asynchronously.
  44   // The actual parameters for the operation are setup in the constructor of
  45   // the object. Both methods should be called from a worker thread, by posting
  46   // a task to the WorkerPool (they are RunnableMethods). When finished,
  47   // controller->OnIOComplete() is called.
  48   void Read();
  49   void Write();
  50
  51  private:
  52   virtual ~FileBackgroundIO() {}
  53
  54   disk_cache::FileIOCallback* callback_;
  55
  56   disk_cache::File* file_;
  57   const void* buf_;
  58   size_t buf_len_;
  59   size_t offset_;
  60
  61   DISALLOW_COPY_AND_ASSIGN(FileBackgroundIO);
  62 };
  63
  64
  65 // The specialized controller that keeps track of current operations.
  66 class FileInFlightIO : public disk_cache::InFlightIO {
  67  public:
  68   FileInFlightIO() {}
  69   virtual ~FileInFlightIO() {}
  70
  71   // These methods start an asynchronous operation. The arguments have the same
  72   // semantics of the File asynchronous operations, with the exception that the
  73   // operation never finishes synchronously.
  74   void PostRead(disk_cache::File* file, void* buf, size_t buf_len,
  75                 size_t offset, disk_cache::FileIOCallback* callback);
  76   void PostWrite(disk_cache::File* file, const void* buf, size_t buf_len,
  77                  size_t offset, disk_cache::FileIOCallback* callback);
  78
  79  protected:
  80   // Invokes the users' completion callback at the end of the IO operation.
  81   // |cancel| is true if the actual task posted to the thread is still
  82   // queued (because we are inside WaitForPendingIO), and false if said task is
  83   // the one performing the call.
  84   virtual void OnOperationComplete(disk_cache::BackgroundIO* operation,
  85                                    bool cancel) OVERRIDE;
  86
  87  private:
  88   DISALLOW_COPY_AND_ASSIGN(FileInFlightIO);
  89 };
  90
  91 // ---------------------------------------------------------------------------
  92
  93 // Runs on a worker thread.
  94 void FileBackgroundIO::Read() {
  95   if (file_->Read(const_cast<void*>(buf_), buf_len_, offset_)) {
  96     result_ = static_cast<int>(buf_len_);
  97   } else {
  98     result_ = net::ERR_CACHE_READ_FAILURE;
  99   }
 100   NotifyController();
 101 }
 102
 103 // Runs on a worker thread.
 104 void FileBackgroundIO::Write() {
 105   bool rv = file_->Write(buf_, buf_len_, offset_);
 106
 107   result_ = rv ? static_cast<int>(buf_len_) : net::ERR_CACHE_WRITE_FAILURE;
 108   NotifyController();
 109 }
 110
 111 // ---------------------------------------------------------------------------
 112
 113 void FileInFlightIO::PostRead(disk_cache::File *file, void* buf, size_t buf_len,
 114                           size_t offset, disk_cache::FileIOCallback *callback) {
 115   scoped_refptr<FileBackgroundIO> operation(
 116       new FileBackgroundIO(file, buf, buf_len, offset, callback, this));
 117   file->AddRef();  // Balanced on OnOperationComplete()
 118
 119   base::WorkerPool::PostTask(FROM_HERE,
 120       base::Bind(&FileBackgroundIO::Read, operation.get()), true);
 121   OnOperationPosted(operation.get());
 122 }
 123
 124 void FileInFlightIO::PostWrite(disk_cache::File* file, const void* buf,
 125                            size_t buf_len, size_t offset,
 126                            disk_cache::FileIOCallback* callback) {
 127   scoped_refptr<FileBackgroundIO> operation(
 128       new FileBackgroundIO(file, buf, buf_len, offset, callback, this));
 129   file->AddRef();  // Balanced on OnOperationComplete()
 130
 131   base::WorkerPool::PostTask(FROM_HERE,
 132       base::Bind(&FileBackgroundIO::Write, operation.get()), true);
 133   OnOperationPosted(operation.get());
 134 }
 135
 136 // Runs on the IO thread.
 137 void FileInFlightIO::OnOperationComplete(disk_cache::BackgroundIO* operation,
 138                                          bool cancel) {
 139   FileBackgroundIO* op = static_cast<FileBackgroundIO*>(operation);
 140
 141   disk_cache::FileIOCallback* callback = op->callback();
 142   int bytes = operation->result();
 143
 144   // Release the references acquired in PostRead / PostWrite.
 145   op->file()->Release();
 146   callback->OnFileIOComplete(bytes);
 147 }
 148
 149 // A static object tha will broker all async operations.
 150 FileInFlightIO* s_file_operations = NULL;
 151
 152 // Returns the current FileInFlightIO.
 153 FileInFlightIO* GetFileInFlightIO() {
 154   if (!s_file_operations) {
 155     s_file_operations = new FileInFlightIO;
 156   }
 157   return s_file_operations;
 158 }
 159
 160 // Deletes the current FileInFlightIO.
 161 void DeleteFileInFlightIO() {
 162   DCHECK(s_file_operations);
 163   delete s_file_operations;
 164   s_file_operations = NULL;
 165 }
 166
 167 }  // namespace
 168
 169 namespace disk_cache {
 170
 171 File::File(base::PlatformFile file)
 172     : init_(true),
 173       mixed_(true),
 174       platform_file_(file),
 175       sync_platform_file_(base::kInvalidPlatformFileValue) {
 176 }
 177
 178 bool File::Init(const base::FilePath& name) {
 179   if (init_)
 180     return false;
 181
 182   int flags = base::PLATFORM_FILE_OPEN |
 183               base::PLATFORM_FILE_READ |
 184               base::PLATFORM_FILE_WRITE;
 185   platform_file_ = base::CreatePlatformFile(name, flags, NULL, NULL);
 186   if (platform_file_ < 0) {
 187     platform_file_ = 0;
 188     return false;
 189   }
 190
 191   init_ = true;
 192   return true;
 193 }
 194
 195 base::PlatformFile File::platform_file() const {
 196   return platform_file_;
 197 }
 198
 199 bool File::IsValid() const {
 200   if (!init_)
 201     return false;
 202   return (base::kInvalidPlatformFileValue != platform_file_);
 203 }
 204
 205 bool File::Read(void* buffer, size_t buffer_len, size_t offset) {
 206   DCHECK(init_);
 207   if (buffer_len > static_cast<size_t>(kint32max) ||
 208       offset > static_cast<size_t>(kint32max))
 209     return false;
 210
 211   int ret = base::ReadPlatformFile(platform_file_, offset,
 212                                    static_cast<char*>(buffer), buffer_len);
 213   return (static_cast<size_t>(ret) == buffer_len);
 214 }
 215
 216 bool File::Write(const void* buffer, size_t buffer_len, size_t offset) {
 217   DCHECK(init_);
 218   if (buffer_len > static_cast<size_t>(kint32max) ||
 219       offset > static_cast<size_t>(kint32max))
 220     return false;
 221
 222   int ret = base::WritePlatformFile(platform_file_, offset,
 223                                     static_cast<const char*>(buffer),
 224                                     buffer_len);
 225   return (static_cast<size_t>(ret) == buffer_len);
 226 }
 227
 228 // We have to increase the ref counter of the file before performing the IO to
 229 // prevent the completion to happen with an invalid handle (if the file is
 230 // closed while the IO is in flight).
 231 bool File::Read(void* buffer, size_t buffer_len, size_t offset,
 232                 FileIOCallback* callback, bool* completed) {
 233   DCHECK(init_);
 234   if (!callback) {
 235     if (completed)
 236       *completed = true;
 237     return Read(buffer, buffer_len, offset);
 238   }
 239
 240   if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
 241     return false;
 242
 243   GetFileInFlightIO()->PostRead(this, buffer, buffer_len, offset, callback);
 244
 245   *completed = false;
 246   return true;
 247 }
 248
 249 bool File::Write(const void* buffer, size_t buffer_len, size_t offset,
 250                  FileIOCallback* callback, bool* completed) {
 251   DCHECK(init_);
 252   if (!callback) {
 253     if (completed)
 254       *completed = true;
 255     return Write(buffer, buffer_len, offset);
 256   }
 257
 258   return AsyncWrite(buffer, buffer_len, offset, callback, completed);
 259 }
 260
 261 bool File::SetLength(size_t length) {
 262   DCHECK(init_);
 263   if (length > ULONG_MAX)
 264     return false;
 265
 266   return base::TruncatePlatformFile(platform_file_, length);
 267 }
 268
 269 size_t File::GetLength() {
 270   DCHECK(init_);
 271   off_t ret = lseek(platform_file_, 0, SEEK_END);
 272   if (ret < 0)
 273     return 0;
 274   return ret;
 275 }
 276
 277 // Static.
 278 void File::WaitForPendingIO(int* num_pending_io) {
 279   // We may be running unit tests so we should allow be able to reset the
 280   // message loop.
 281   GetFileInFlightIO()->WaitForPendingIO();
 282   DeleteFileInFlightIO();
 283 }
 284
 285 // Static.
 286 void File::DropPendingIO() {
 287   GetFileInFlightIO()->DropPendingIO();
 288   DeleteFileInFlightIO();
 289 }
 290
 291 File::~File() {
 292   if (IsValid())
 293     base::ClosePlatformFile(platform_file_);
 294 }
 295
 296 bool File::AsyncWrite(const void* buffer, size_t buffer_len, size_t offset,
 297                       FileIOCallback* callback, bool* completed) {
 298   DCHECK(init_);
 299   if (buffer_len > ULONG_MAX || offset > ULONG_MAX)
 300     return false;
 301
 302   GetFileInFlightIO()->PostWrite(this, buffer, buffer_len, offset, callback);
 303
 304   if (completed)
 305     *completed = false;
 306   return true;
 307 }
 308
 309 }  // namespace disk_cache