net: Use DrainableIOBuffer in URLFetcherFileWriter

With DrainableIOBuffer, there is no need to maintain |pending_bytes_| and |buffer_offset_| manually.

BUG=126753
TEST=net_unittests


Review URL: https://chromiumcodereview.appspot.com/12297023

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@183440 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 8 insertions, 21 deletions

diff --git a/net/url_request/url_fetcher_file_writer.cc b/net/url_request/url_fetcher_file_writer.cc
index bd70b57..07da472 100644
--- a/net/url_request/url_fetcher_file_writer.cc
+++ b/net/url_request/url_fetcher_file_writer.cc
@@ -49,16 +49,12 @@ void URLFetcherFileWriter::CreateTempFile(const CompletionCallback& callback) {
 void URLFetcherFileWriter::Write(scoped_refptr<IOBuffer> buffer,
                                  int num_bytes,
                                  const CompletionCallback& callback) {
-  // Start writing to the file by setting the initial state
-  // of |pending_bytes_| and |buffer_offset_| to indicate that the
-  // entire buffer has not yet been written.
-  pending_bytes_ = num_bytes;
-  buffer_offset_ = 0;
-  ContinueWrite(buffer, callback, base::PLATFORM_FILE_OK, 0);
+  ContinueWrite(new DrainableIOBuffer(buffer, num_bytes), callback,
+                base::PLATFORM_FILE_OK, 0);
 }
 
 void URLFetcherFileWriter::ContinueWrite(
-    scoped_refptr<IOBuffer> buffer,
+    scoped_refptr<DrainableIOBuffer> buffer,
     const CompletionCallback& callback,
     base::PlatformFileError error_code,
     int bytes_written) {
@@ -78,14 +74,13 @@ void URLFetcherFileWriter::ContinueWrite(
   }
 
   total_bytes_written_ += bytes_written;
-  buffer_offset_ += bytes_written;
-  pending_bytes_ -= bytes_written;
+  buffer->DidConsume(bytes_written);
 
-  if (pending_bytes_ > 0) {
+  if (buffer->BytesRemaining() > 0) {
     base::FileUtilProxy::Write(
         file_task_runner_, file_handle_,
         total_bytes_written_,  // Append to the end
-        (buffer->data() + buffer_offset_), pending_bytes_,
+        buffer->data(), buffer->BytesRemaining(),
         base::Bind(&URLFetcherFileWriter::ContinueWrite,
                    weak_factory_.GetWeakPtr(),
                    buffer,
diff --git a/net/url_request/url_fetcher_file_writer.h b/net/url_request/url_fetcher_file_writer.h
index 6a14409..3596f2b 100644
--- a/net/url_request/url_fetcher_file_writer.h
+++ b/net/url_request/url_fetcher_file_writer.h
@@ -18,6 +18,7 @@ class TaskRunner;
 
 namespace net {
 
+class DrainableIOBuffer;
 class IOBuffer;
 
 // This class encapsulates all state involved in writing URLFetcher response
@@ -38,7 +39,7 @@ class URLFetcherFileWriter {
 
   // Called when a write has been done.  Continues writing if there are more
   // bytes to write.  Otherwise, runs |callback|.
-  void ContinueWrite(scoped_refptr<IOBuffer> buffer,
+  void ContinueWrite(scoped_refptr<DrainableIOBuffer> buffer,
                      const CompletionCallback& callback,
                      base::PlatformFileError error_code,
                      int bytes_written);
@@ -103,15 +104,6 @@ class URLFetcherFileWriter {
   // written, so that writes know the offset to give.
   int64 total_bytes_written_;
 
-  // How many bytes did the last Write() try to write?  Needed so
-  // that if not all the bytes get written on a Write(), we can
-  // call Write() again with the rest.
-  int pending_bytes_;
-
-  // When writing, how many bytes from the buffer have been successfully
-  // written so far?
-  int buffer_offset_;
-
   DISALLOW_COPY_AND_ASSIGN(URLFetcherFileWriter);
 };