Make URLFetcherFileWriter::Finish() skip closing file when there is an error

net/url_request/url_fetcher_response_writer.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_URL_REQUEST_URL_FETCHER_RESPONSE_WRITER_H_
 #define NET_URL_REQUEST_URL_FETCHER_RESPONSE_WRITER_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 27 matching lines @@
   // Initialize() success results in discarding already written data.
   virtual int Initialize(const CompletionCallback& callback) = 0;
 
   // Writes |num_bytes| bytes in |buffer|, and returns the number of bytes
   // written or an error code. If ERR_IO_PENDING is returned, |callback| will be
   // run later with the result.
   virtual int Write(IOBuffer* buffer,
                     int num_bytes,
                     const CompletionCallback& callback) = 0;
 
-  // Finishes writing. If ERR_IO_PENDING is returned, |callback| will be run
+  // Finishes writing. If |net_error| is not OK, the writer might choose to skip
+  // graceful shutdown. If ERR_IO_PENDING is returned, |callback| will be run

[mmenke, 2016/10/19 14:32:29]

Also, think we should be more explicit that if net_error is not OK, this may be
called in the middle of another operation (We could actually wait for the write
to complete instead, but that gets complicated)

[xunjieli, 2016/10/19 15:19:28]

Done.

   // later with the result.
-  virtual int Finish(const CompletionCallback& callback) = 0;
+  virtual int Finish(int net_error, const CompletionCallback& callback) = 0;
 
   // Returns this instance's pointer as URLFetcherStringWriter when possible.
   virtual URLFetcherStringWriter* AsStringWriter();
 
   // Returns this instance's pointer as URLFetcherFileWriter when possible.
   virtual URLFetcherFileWriter* AsFileWriter();
 };
 
 // URLFetcherResponseWriter implementation for std::string.
 class NET_EXPORT URLFetcherStringWriter : public URLFetcherResponseWriter {
  public:
   URLFetcherStringWriter();
   ~URLFetcherStringWriter() override;
 
   const std::string& data() const { return data_; }
 
   // URLFetcherResponseWriter overrides:
   int Initialize(const CompletionCallback& callback) override;
   int Write(IOBuffer* buffer,
             int num_bytes,
             const CompletionCallback& callback) override;
-  int Finish(const CompletionCallback& callback) override;
+  int Finish(int net_error, const CompletionCallback& callback) override;
   URLFetcherStringWriter* AsStringWriter() override;
 
  private:
   std::string data_;
 
   DISALLOW_COPY_AND_ASSIGN(URLFetcherStringWriter);
 };
 
 // URLFetcherResponseWriter implementation for files.
 class NET_EXPORT URLFetcherFileWriter : public URLFetcherResponseWriter {
  public:
   // |file_path| is used as the destination path. If |file_path| is empty,
   // Initialize() will create a temporary file.
   URLFetcherFileWriter(
       scoped_refptr<base::SequencedTaskRunner> file_task_runner,
       const base::FilePath& file_path);
   ~URLFetcherFileWriter() override;
 
   const base::FilePath& file_path() const { return file_path_; }
 
   // URLFetcherResponseWriter overrides:
   int Initialize(const CompletionCallback& callback) override;
   int Write(IOBuffer* buffer,
             int num_bytes,
             const CompletionCallback& callback) override;
-  int Finish(const CompletionCallback& callback) override;
+  int Finish(int net_error, const CompletionCallback& callback) override;
   URLFetcherFileWriter* AsFileWriter() override;
 
   // Drops ownership of the file at |file_path_|.
   // This class will not delete it or write to it again.
   void DisownFile();
 
  private:
   // Called when a write has been done.
   void DidWrite(const CompletionCallback& callback, int result);
 
@@ skipping 26 matching lines @@
 
   // Callbacks are created for use with base::FileUtilProxy.
   base::WeakPtrFactory<URLFetcherFileWriter> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(URLFetcherFileWriter);
 };
 
 }  // namespace net
 
 #endif  // NET_URL_REQUEST_URL_FETCHER_RESPONSE_WRITER_H_