chrome/browser/chromeos/extensions/file_manager/file_stream_md5_digester.h

   1 // Copyright 2015 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 #ifndef CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_FILE_STREAM_MD5_DIGESTER_H_
   6 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_FILE_STREAM_MD5_DIGESTER_H_
   7
   8 #include "base/callback_forward.h"
   9 #include "base/macros.h"
  10 #include "base/md5.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "net/base/io_buffer.h"
  14
  15 namespace storage {
  16 class FileStreamReader;
  17 }
  18
  19 namespace drive {
  20 namespace util {
  21
  22 // Computes the (base-16 encoded) MD5 digest of data extracted from a file
  23 // stream.
  24 class FileStreamMd5Digester {
  25  public:
  26   typedef base::Callback<void(const std::string&)> ResultCallback;
  27
  28   FileStreamMd5Digester();
  29   ~FileStreamMd5Digester();
  30
  31   // Computes an MD5 digest of data read from the given |streamReader|.  The
  32   // work occurs asynchronously, and the resulting hash is returned via the
  33   // |callback|.  If an error occurs, |callback| is called with an empty string.
  34   // Only one stream can be processed at a time by each digester.  Do not call
  35   // GetMd5Digest before the results of a previous call have been returned.
  36   void GetMd5Digest(scoped_ptr<storage::FileStreamReader> stream_reader,
  37                     const ResultCallback& callback);
  38
  39  private:
  40   // Kicks off a read of the next chunk from the stream.
  41   void ReadNextChunk(const ResultCallback& callback);
  42   // Handles the incoming chunk of data from a stream read.
  43   void OnChunkRead(const ResultCallback& callback, int bytes_read);
  44
  45   // Maximum chunk size for read operations.
  46   scoped_ptr<storage::FileStreamReader> reader_;
  47   scoped_refptr<net::IOBuffer> buffer_;
  48   base::MD5Context md5_context_;
  49
  50   DISALLOW_COPY_AND_ASSIGN(FileStreamMd5Digester);
  51 };
  52
  53 }  // namespace util
  54 }  // namespace drive
  55
  56 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_MANAGER_FILE_STREAM_MD5_DIGESTER_H_