net/url_request/url_fetcher_response_writer.h

   1 // Copyright (c) 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 #ifndef NET_URL_REQUEST_URL_FETCHER_RESPONSE_WRITER_H_
   6 #define NET_URL_REQUEST_URL_FETCHER_RESPONSE_WRITER_H_
   7
   8 #include <string>
   9
  10 #include "base/basictypes.h"
  11 #include "base/files/file_path.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/memory/weak_ptr.h"
  15 #include "net/base/completion_callback.h"
  16 #include "net/base/net_export.h"
  17
  18 namespace base {
  19 class SequencedTaskRunner;
  20 }  // namespace base
  21
  22 namespace net {
  23
  24 class DrainableIOBuffer;
  25 class FileStream;
  26 class IOBuffer;
  27 class URLFetcherFileWriter;
  28 class URLFetcherStringWriter;
  29
  30 // This class encapsulates all state involved in writing URLFetcher response
  31 // bytes to the destination.
  32 class NET_EXPORT URLFetcherResponseWriter {
  33  public:
  34   virtual ~URLFetcherResponseWriter() {}
  35
  36   // Initializes this instance. If ERR_IO_PENDING is returned, |callback| will
  37   // be run later with the result. Calling this method again after a
  38   // Initialize() success results in discarding already written data.
  39   virtual int Initialize(const CompletionCallback& callback) = 0;
  40
  41   // Writes |num_bytes| bytes in |buffer|, and returns the number of bytes
  42   // written or an error code. If ERR_IO_PENDING is returned, |callback| will be
  43   // run later with the result.
  44   virtual int Write(IOBuffer* buffer,
  45                     int num_bytes,
  46                     const CompletionCallback& callback) = 0;
  47
  48   // Finishes writing. If ERR_IO_PENDING is returned, |callback| will be run
  49   // later with the result.
  50   virtual int Finish(const CompletionCallback& callback) = 0;
  51
  52   // Returns this instance's pointer as URLFetcherStringWriter when possible.
  53   virtual URLFetcherStringWriter* AsStringWriter();
  54
  55   // Returns this instance's pointer as URLFetcherFileWriter when possible.
  56   virtual URLFetcherFileWriter* AsFileWriter();
  57 };
  58
  59 // URLFetcherResponseWriter implementation for std::string.
  60 class NET_EXPORT URLFetcherStringWriter : public URLFetcherResponseWriter {
  61  public:
  62   URLFetcherStringWriter();
  63   ~URLFetcherStringWriter() override;
  64
  65   const std::string& data() const { return data_; }
  66
  67   // URLFetcherResponseWriter overrides:
  68   int Initialize(const CompletionCallback& callback) override;
  69   int Write(IOBuffer* buffer,
  70             int num_bytes,
  71             const CompletionCallback& callback) override;
  72   int Finish(const CompletionCallback& callback) override;
  73   URLFetcherStringWriter* AsStringWriter() override;
  74
  75  private:
  76   std::string data_;
  77
  78   DISALLOW_COPY_AND_ASSIGN(URLFetcherStringWriter);
  79 };
  80
  81 // URLFetcherResponseWriter implementation for files.
  82 class NET_EXPORT URLFetcherFileWriter : public URLFetcherResponseWriter {
  83  public:
  84   // |file_path| is used as the destination path. If |file_path| is empty,
  85   // Initialize() will create a temporary file.
  86   URLFetcherFileWriter(
  87       scoped_refptr<base::SequencedTaskRunner> file_task_runner,
  88       const base::FilePath& file_path);
  89   ~URLFetcherFileWriter() override;
  90
  91   const base::FilePath& file_path() const { return file_path_; }
  92
  93   // URLFetcherResponseWriter overrides:
  94   int Initialize(const CompletionCallback& callback) override;
  95   int Write(IOBuffer* buffer,
  96             int num_bytes,
  97             const CompletionCallback& callback) override;
  98   int Finish(const CompletionCallback& callback) override;
  99   URLFetcherFileWriter* AsFileWriter() override;
 100
 101   // Drops ownership of the file at |file_path_|.
 102   // This class will not delete it or write to it again.
 103   void DisownFile();
 104
 105  private:
 106   // Called when a write has been done.
 107   void DidWrite(const CompletionCallback& callback, int result);
 108
 109   // Closes the file if it is open and then delete it.
 110   void CloseAndDeleteFile();
 111
 112   // Callback which gets the result of a temporary file creation.
 113   void DidCreateTempFile(const CompletionCallback& callback,
 114                          base::FilePath* temp_file_path,
 115                          bool success);
 116
 117   // Callback which gets the result of FileStream::Open.
 118   void DidOpenFile(const CompletionCallback& callback,
 119                    int result);
 120
 121   // Callback which gets the result of closing a file.
 122   void CloseComplete(const CompletionCallback& callback, int result);
 123
 124   // Task runner on which file operations should happen.
 125   scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
 126
 127   // Destination file path.
 128   // Initialize() creates a temporary file if this variable is empty.
 129   base::FilePath file_path_;
 130
 131   // True when this instance is responsible to delete the file at |file_path_|.
 132   bool owns_file_;
 133
 134   scoped_ptr<FileStream> file_stream_;
 135
 136   // Callbacks are created for use with base::FileUtilProxy.
 137   base::WeakPtrFactory<URLFetcherFileWriter> weak_factory_;
 138
 139   DISALLOW_COPY_AND_ASSIGN(URLFetcherFileWriter);
 140 };
 141
 142 }  // namespace net
 143
 144 #endif  // NET_URL_REQUEST_URL_FETCHER_RESPONSE_WRITER_H_