net: Make UploadDataStream::Init() asynchronous.

net/base/upload_data_stream.h

 // Copyright (c) 2012 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_BASE_UPLOAD_DATA_STREAM_H_
 #define NET_BASE_UPLOAD_DATA_STREAM_H_
 #pragma once
 
+#include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "net/base/completion_callback.h"
 #include "net/base/net_export.h"
 #include "net/base/upload_data.h"
 
 namespace net {
 
 class FileStream;
 class IOBuffer;
 
 class NET_EXPORT UploadDataStream {
  public:
   explicit UploadDataStream(UploadData* upload_data);
   ~UploadDataStream();
 
-  // Initializes the stream. This function must be called exactly once,
-  // before calling any other method. It is not valid to call any method
-  // (other than the destructor) if Init() returns a failure.
+  // Initializes the stream synchronously or asynchronously depending on
+  // whether the upload data is in memory or not. This function must be
+  // called exactly once, before calling any other method. It is not valid to
+  // call any method (other than the destructor) if the initialization
+  // failed.
   //
-  // Returns OK on success. Returns ERR_UPLOAD_FILE_CHANGED if the expected
+  // If the upload data is in memory, the initialization is done
+  // synchronously. Returns OK or some other error code.
+  //
+  // If initialization requires file IO, returns ERR_IO_PENDING, and runs
+  // |on_completion| with a result code on the original thread once the
+  // initialization is done.
+  //
+  // ERR_UPLOAD_FILE_CHANGED is passed to |on_completion| if the expected
   // file modification time is set (usually not set, but set for sliced
   // files) and the target file is changed.
-  int Init();
+  int Init(const CompletionCallback & on_completion);
+
+  // Similar to Init() but performs the operation always synchronously. This
+  // version may perform file IO on the current thread. This function will
+  // fail if called on a thread where file IO is prohibited. Usually used for
+  // testing, but Chrome Frame also uses this version.
+  int InitSync();
 
   // Reads up to |buf_len| bytes from the upload data stream to |buf|. The
   // number of bytes read is returned. Partial reads are allowed.  Zero is
   // returned on a call to Read when there are no remaining bytes in the
   // stream, and IsEof() will return true hereafter.
   //
   // If there's less data to read than we initially observed (i.e. the actual
   // upload data is smaller than size()), zeros are padded to ensure that
   // size() bytes can be read, which can happen for TYPE_FILE payloads.
   //
@@ skipping 24 matching lines @@
   // Returns true if the upload data in the stream is entirely in memory.
   bool IsInMemory() const;
 
   // This method is provided only to be used by unit tests.
   static void set_merge_chunks(bool merge) { merge_chunks_ = merge; }
 
  private:
   // Advances to the next element. Updates the internal states.
   void AdvanceToNextElement();
 
+  // Called when GetContentLength() is completed. Used to implement Init().
+  void OnGetContentLengthComplete(uint64 content_length);
+
+  // Called when CheckModifiedFiles() is completed. Used to implement Init().
+  void OnCheckModifiedFilesComplete(int* result);
+
   scoped_refptr<UploadData> upload_data_;
 
   // 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 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 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 current element is of TYPE_FILE.
   uint64 element_file_bytes_remaining_;
 
   // Size and current read position within the upload data stream.
   uint64 total_size_;
   uint64 current_position_;
 
   // True if the initialization was successful.
   bool initialized_successfully_;
 
+  // The user supplied callback for asynchronous operations.
+  CompletionCallback user_callback_;
+
   // TODO(satish): Remove this once we have a better way to unit test POST
   // requests with chunked uploads.
   static bool merge_chunks_;
 
+  base::WeakPtrFactory<UploadDataStream> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(UploadDataStream);
 };
 
 }  // namespace net
 
 #endif  // NET_BASE_UPLOAD_DATA_STREAM_H_