In BlobURLRequestJob, open files asynchronously to avoid blocking the IO thread

webkit/blob/blob_url_request_job.h

 // Copyright (c) 20010 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 WEBKIT_BLOB_BLOB_URL_REQUEST_JOB_H_
 #define WEBKIT_BLOB_BLOB_URL_REQUEST_JOB_H_
 
 #include "base/platform_file.h"
 #include "base/ref_counted.h"
 #include "base/scoped_callback_factory.h"
 #include "base/scoped_ptr.h"
 #include "base/task.h"
 #include "net/base/completion_callback.h"
-#include "net/base/file_stream.h"
 #include "net/http/http_byte_range.h"
 #include "net/url_request/url_request_job.h"
 #include "webkit/blob/blob_data.h"
 
 namespace base {
 class MessageLoopProxy;
 struct PlatformFileInfo;
 }
 
+namespace net {
+class FileStream;
+}
+
 namespace webkit_blob {
 
 // A request job that handles reading blob URLs.
 class BlobURLRequestJob : public net::URLRequestJob {
  public:
   BlobURLRequestJob(net::URLRequest* request,
                     BlobData* blob_data,
                     base::MessageLoopProxy* resolving_message_loop_proxy);
   virtual ~BlobURLRequestJob();
 
   // net::URLRequestJob methods.
   virtual void Start();
   virtual void Kill();
   virtual bool ReadRawData(net::IOBuffer* buf, int buf_size, int* bytes_read);
   virtual bool GetMimeType(std::string* mime_type) const;
   virtual void GetResponseInfo(net::HttpResponseInfo* info);
   virtual int GetResponseCode() const;
   virtual void SetExtraRequestHeaders(const net::HttpRequestHeaders& headers);
 
  private:
+  void CloseStream();
   void ResolveFile(const FilePath& file_path);
   void CountSize();
   void Seek(int64 offset);
   void AdvanceItem();
   void AdvanceBytesRead(int result);
+  int ComputeBytesToRead() const;
   bool ReadLoop(int* bytes_read);
   bool ReadItem();
-  bool ReadBytes(const BlobData::Item& item, int bytes_to_read);
-  bool ReadFile(const BlobData::Item& item, int bytes_to_read);
+  bool ReadBytes(const BlobData::Item& item);
+  bool DispatchReadFile(const BlobData::Item& item);
+  bool ReadFile(const BlobData::Item& item);
   void HeadersCompleted(int status_code, const std::string& status_txt);
   int ReadCompleted();
   void NotifySuccess();
   void NotifyFailure(int);
 
   void DidStart();
   void DidResolve(base::PlatformFileError rv,
                   const base::PlatformFileInfo& file_info);
+  void DidOpen(base::PlatformFileError rv,
+               base::PassPlatformFile file,
+               bool created);
   void DidRead(int result);
 
   base::ScopedCallbackFactory<BlobURLRequestJob> callback_factory_;
   scoped_refptr<BlobData> blob_data_;
   scoped_refptr<base::MessageLoopProxy> file_thread_proxy_;
   net::CompletionCallbackImpl<BlobURLRequestJob> io_callback_;
   std::vector<int64> item_length_list_;
-  net::FileStream stream_;
+  scoped_ptr<net::FileStream> stream_;
   size_t item_index_;
   int64 total_size_;
   int64 current_item_offset_;
   int64 remaining_bytes_;
   scoped_refptr<net::IOBuffer> read_buf_;
   int read_buf_offset_;
   int read_buf_size_;
   int read_buf_remaining_bytes_;
+  int bytes_to_read_;
   bool error_;
   bool headers_set_;
   bool byte_range_set_;
   net::HttpByteRange byte_range_;
   scoped_ptr<net::HttpResponseInfo> response_info_;
   ScopedRunnableMethodFactory<BlobURLRequestJob> method_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BlobURLRequestJob);
 };
 
 }  // namespace webkit_blob
 
 #endif  // WEBKIT_BLOB_BLOB_URL_REQUEST_JOB_H_