[ON HOLD] Implement pull-based design for content decoding

net/url_request/url_request_file_job.cc

 // 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.
 
 // For loading files, we make use of overlapped i/o to ensure that reading from
 // the filesystem (e.g., a network filesystem) does not block the calling
 // thread.  An alternative approach would be to use a background thread or pool
 // of threads, but it seems better to leverage the operating system's ability
 // to do background file reads for us.
 //
 // Since overlapped reads require a 'static' buffer for the duration of the
 // asynchronous read, the URLRequestFileJob keeps a buffer as a member var.  In
 // URLRequestFileJob::Read, data is simply copied from the object's buffer into
 // the given buffer.  If there is no data to copy, the URLRequestFileJob
 // attempts to read more from the file to fill its buffer.  If reading from the
 // file does not complete synchronously, then the URLRequestFileJob waits for a
 // signal from the OS that the overlapped read has completed.  It does so by
 // leveraging the MessageLoop::WatchObject API.
 
 #include "net/url_request/url_request_file_job.h"
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/files/file_util.h"
+#include "base/memory/ptr_util.h"

[mmenke, 2016/07/21 18:14:09]

What's this being used for?

[xunjieli, 2016/07/27 20:32:03]

Done.

 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_util.h"
 #include "base/synchronization/lock.h"
 #include "base/task_runner.h"
 #include "base/threading/thread_restrictions.h"
 #include "build/build_config.h"
 #include "net/base/file_stream.h"
 #include "net/base/filename_util.h"
 #include "net/base/io_buffer.h"
 #include "net/base/load_flags.h"
 #include "net/base/mime_util.h"
-#include "net/filter/filter.h"
+#include "net/filter/gzip_stream_source.h"
+#include "net/filter/stream_source.h"
 #include "net/http/http_util.h"
 #include "net/url_request/url_request_error_job.h"
 #include "net/url_request/url_request_file_dir_job.h"
 #include "url/gurl.h"
 
 #if defined(OS_WIN)
 #include "base/win/shortcut.h"
 #endif
 
 namespace net {
@@ skipping 91 matching lines @@
     return false;
 
   *location = FilePathToFileURL(new_path);
   *http_status_code = 301;
   return true;
 #else
   return false;
 #endif
 }
 
-std::unique_ptr<Filter> URLRequestFileJob::SetupFilter() const {
-  // Bug 9936 - .svgz files needs to be decompressed.
-  return base::LowerCaseEqualsASCII(file_path_.Extension(), ".svgz")
-             ? Filter::GZipFactory()
-             : nullptr;
+std::unique_ptr<StreamSource> URLRequestFileJob::SetupSource() {
+  std::unique_ptr<StreamSource> source = URLRequestJob::SetupSource();
+  if (!base::LowerCaseEqualsASCII(file_path_.Extension(), ".svgz"))
+    return source;
+
+  std::unique_ptr<GzipStreamSource> gzip(new GzipStreamSource(
+      std::move(source), GzipStreamSource::GZIP_STREAM_SOURCE_GZIP));
+  if (gzip->Init())
+    return std::move(gzip);
+  return nullptr;
 }
 
 bool URLRequestFileJob::GetMimeType(std::string* mime_type) const {
   DCHECK(request_);
   if (meta_info_.mime_type_result) {
     *mime_type = meta_info_.mime_type;
     return true;
   }
   return false;
 }
@@ skipping 130 matching lines @@
     DCHECK_GE(remaining_bytes_, 0);
   }
 
   OnReadComplete(buf.get(), result);
   buf = NULL;
 
   ReadRawDataComplete(result);
 }
 
 }  // namespace net