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