Improve readability of UploadDataStream.

Many variable names in the code are misleading or not descriptive.
In particular, next_element_* are misleading as these are referring
to the current element currently being read.

Along the way, add some comments, and clean up some pieces of code.

BUG=72001
TEST=run tests via try bots


Review URL: http://codereview.chromium.org/9212015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@118854 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 26 insertions, 17 deletions

diff --git a/net/base/upload_data_stream.h b/net/base/upload_data_stream.h
index e71cc68..f0a59fa 100644
--- a/net/base/upload_data_stream.h
+++ b/net/base/upload_data_stream.h
@@ -22,7 +22,7 @@ class NET_EXPORT UploadDataStream {
   // Returns a new instance of UploadDataStream if it can be created and
   // initialized successfully. If not, NULL will be returned and the error
   // code will be set if the output parameter error_code is not empty.
-  static UploadDataStream* Create(UploadData* data, int* error_code);
+  static UploadDataStream* Create(UploadData* upload_data, int* error_code);
 
   // Returns the stream's buffer.
   IOBuffer* buf() const { return buf_; }
@@ -44,7 +44,7 @@ class NET_EXPORT UploadDataStream {
 
   // Sets the callback to be invoked when new chunks are available to upload.
   void set_chunk_callback(ChunkCallback* callback) {
-    data_->set_chunk_callback(callback);
+    upload_data_->set_chunk_callback(callback);
   }
 
   // Returns the total size of the data stream and the current position.
@@ -54,7 +54,7 @@ class NET_EXPORT UploadDataStream {
   uint64 size() const { return total_size_; }
   uint64 position() const { return current_position_; }
 
-  bool is_chunked() const { return data_->is_chunked(); }
+  bool is_chunked() const { return upload_data_->is_chunked(); }
 
   // Returns whether there is no more data to read, regardless of whether
   // position < size.
@@ -75,14 +75,21 @@ class NET_EXPORT UploadDataStream {
  private:
   // Protects from public access since now we have a static creator function
   // which will do both creation and initialization and might return an error.
-  explicit UploadDataStream(UploadData* data);
+  explicit UploadDataStream(UploadData* upload_data);
 
   // Fills the buffer with any remaining data and sets eof_ if there was nothing
   // left to fill the buffer with.
   // Returns OK if the operation succeeds. Otherwise error code is returned.
-  int FillBuf();
+  int FillBuffer();
 
-  scoped_refptr<UploadData> data_;
+  // Advances to the next element. Updates the internal states.
+  void AdvanceToNextElement();
+
+  // Returns true if all data has been consumed from this upload data
+  // stream.
+  bool IsEOF() const;
+
+  scoped_refptr<UploadData> upload_data_;
 
   // This buffer is filled with data to be uploaded.  The data to be sent is
   // always at the front of the buffer.  If we cannot send all of the buffer at
@@ -91,22 +98,24 @@ class NET_EXPORT UploadDataStream {
   scoped_refptr<IOBuffer> buf_;
   size_t buf_len_;
 
-  // Index of the upload element to be written to the send buffer next.
-  size_t next_element_;
+  // Index of the current upload element (i.e. the element currently being
+  // read). The index is used as a cursor to iterate over elements in
+  // |upload_data_|.
+  size_t element_index_;
 
-  // The byte offset into next_element_'s data buffer if the next element is
-  // a TYPE_BYTES element.
-  size_t next_element_offset_;
+  // The byte offset into the current element's data buffer if the current
+  // element is a TYPE_BYTES or TYPE_DATA element.
+  size_t element_offset_;
 
-  // A stream to the currently open file, for next_element_ if the next element
-  // is a TYPE_FILE element.
-  scoped_ptr<FileStream> next_element_stream_;
+  // A stream to the currently open file, for the current element if the
+  // current element is a TYPE_FILE element.
+  scoped_ptr<FileStream> element_file_stream_;
 
   // The number of bytes remaining to be read from the currently open file
-  // if the next element is of TYPE_FILE.
-  uint64 next_element_remaining_;
+  // if the current element is of TYPE_FILE.
+  uint64 element_file_bytes_remaining_;
 
-  // Size and current read position within the stream.
+  // Size and current read position within the upload data stream.
   uint64 total_size_;
   uint64 current_position_;