net: Make UploadData::GetContentLength() asynchronous.

net/base/upload_data.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_H_
 #define NET_BASE_UPLOAD_DATA_H_
 #pragma once
 
 #include <vector>
 
 #include "base/basictypes.h"
+#include "base/callback_forward.h"
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/time.h"
 #include "googleurl/src/gurl.h"
 #include "net/base/net_export.h"
 
 namespace net {
 
 class FileStream;
@@ skipping 78 matching lines @@
     void SetToChunk(const char* bytes, int bytes_len, bool is_last_chunk);
 
     bool is_last_chunk() const { return is_last_chunk_; }
     // Sets whether this is the last chunk. Used during IPC marshalling.
     void set_is_last_chunk(bool is_last_chunk) {
       is_last_chunk_ = is_last_chunk;
     }
 
     // Returns the byte-length of the element.  For files that do not exist, 0
     // is returned.  This is done for consistency with Mozilla.
-    // Once called, this function will always return the same value.
     uint64 GetContentLength();
 
     // Returns a FileStream opened for reading for this element, positioned at
     // |file_range_offset_|.  The caller gets ownership and is responsible
     // for cleaning up the FileStream. Returns NULL if this element is not of
     // type TYPE_FILE or if the file is not openable.
     FileStream* NewFileStreamForReading();
 
    private:
     // Allows tests to override the result of GetContentLength.
@@ skipping 35 matching lines @@
   void AppendChunk(const char* bytes, int bytes_len, bool is_last_chunk);
 
   // Sets the callback to be invoked when a new chunk is available to upload.
   void set_chunk_callback(ChunkCallback* callback);
 
   // Initializes the object to send chunks of upload data over time rather
   // than all at once.
   void set_is_chunked(bool set) { is_chunked_ = set; }
   bool is_chunked() const { return is_chunked_; }
 
-  // Returns the total size in bytes of the data to upload.
-  uint64 GetContentLength();
+  // Gets the total size in bytes of the data to upload. Computing the
+  // content length can result in performing file IO hence the operation is
+  // done asynchronously. Runs the callback with the content length once the
+  // computation is done.
+  typedef base::Callback<void(uint64 content_length)> ContentLengthCallback;
+  void GetContentLength(const ContentLengthCallback& callback);
+
+  // Returns the total size in bytes of the data to upload, for testing.
+  // 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.
+  uint64 GetContentLengthSync();
 
   // Returns true if the upload data is entirely in memory (i.e. the
   // upload data is not chunked, and all elemnts are of TYPE_BYTES).
   bool IsInMemory() const;
 
   std::vector<Element>* elements() {
     return &elements_;
   }
 
   void SetElements(const std::vector<Element>& elements);
 
   void swap_elements(std::vector<Element>* elements) {
     elements_.swap(*elements);
   }
 
   // Identifies a particular upload instance, which is used by the cache to
   // formulate a cache key.  This value should be unique across browser
   // sessions.  A value of 0 is used to indicate an unspecified identifier.
   void set_identifier(int64 id) { identifier_ = id; }
   int64 identifier() const { return identifier_; }
 
  private:
+  // Helper function for GetContentLength().
+  void DoGetContentLength(uint64* content_length);
+
   friend class base::RefCounted<UploadData>;
 
   ~UploadData();
 
   std::vector<Element> elements_;
   int64 identifier_;
   ChunkCallback* chunk_callback_;
   bool is_chunked_;
 
   DISALLOW_COPY_AND_ASSIGN(UploadData);
@@ skipping 20 matching lines @@
 
 inline bool operator!=(const UploadData::Element& a,
                        const UploadData::Element& b) {
   return !(a == b);
 }
 #endif  // defined(UNIT_TEST)
 
 }  // namespace net
 
 #endif  // NET_BASE_UPLOAD_DATA_H_