Refactor ResourceHandler API.

content/browser/download/download_resource_handler.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.
 
 #include "content/browser/download/download_resource_handler.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 121 matching lines @@
 
 // static
 std::unique_ptr<ResourceHandler> DownloadResourceHandler::Create(
     net::URLRequest* request) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   std::unique_ptr<ResourceHandler> handler(
       new DownloadResourceHandler(request));
   return handler;
 }
 
-bool DownloadResourceHandler::OnRequestRedirected(
+void DownloadResourceHandler::OnRequestRedirected(
     const net::RedirectInfo& redirect_info,
     ResourceResponse* response,
-    bool* defer) {
-  return core_.OnRequestRedirected();
+    std::unique_ptr<ResourceController> controller) {
+  if (core_.OnRequestRedirected()) {
+    controller->Resume();
+  } else {
+    controller->Cancel();
+  }
 }
 
 // Send the download creation information to the download thread.
-bool DownloadResourceHandler::OnResponseStarted(
+void DownloadResourceHandler::OnResponseStarted(
     ResourceResponse* response,
-    bool* defer) {
+    std::unique_ptr<ResourceController> controller) {
   // The MIME type in ResourceResponse is the product of
   // MimeTypeResourceHandler.
-  return core_.OnResponseStarted(response->head.mime_type);
+  if (core_.OnResponseStarted(response->head.mime_type)) {
+    controller->Resume();
+  } else {
+    controller->Cancel();
+  }
 }
 
-bool DownloadResourceHandler::OnWillStart(const GURL& url, bool* defer) {
-  return true;
+void DownloadResourceHandler::OnWillStart(
+    const GURL& url,
+    std::unique_ptr<ResourceController> controller) {
+  controller->Resume();
 }
 
 // Create a new buffer, which will be handed to the download thread for file
 // writing and deletion.
 bool DownloadResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
                                          int* buf_size,
                                          int min_size) {
   return core_.OnWillRead(buf, buf_size, min_size);
 }
 
 // Pass the buffer to the download file writer.
-bool DownloadResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
-  return core_.OnReadCompleted(bytes_read, defer);
+void DownloadResourceHandler::OnReadCompleted(
+    int bytes_read,
+    std::unique_ptr<ResourceController> controller) {
+  DCHECK(!has_controller());
+
+  bool defer = false;
+  if (!core_.OnReadCompleted(bytes_read, &defer)) {
+    controller->Cancel();
+    return;
+  }
+
+  if (!defer) {

[Charlie Harrison, 2017/01/25 20:22:59]

optional: invert conditions so the positive one is first.

[mmenke, 2017/01/25 22:07:58]

Done.

+    controller->Resume();
+  } else {
+    HoldController(std::move(controller));
+  }
 }
 
 void DownloadResourceHandler::OnResponseCompleted(
     const net::URLRequestStatus& status,
-    bool* defer) {
+    std::unique_ptr<ResourceController> controller) {
   core_.OnResponseCompleted(status);
+  controller->Resume();
 }
 
 void DownloadResourceHandler::OnDataDownloaded(int bytes_downloaded) {
   NOTREACHED();
 }
 
 void DownloadResourceHandler::PauseRequest() {
   core_.PauseRequest();
 }
 
@@ skipping 30 matching lines @@
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
       base::Bind(&StartOnUIThread, base::Passed(&create_info),
                  base::Passed(&tab_info_), base::Passed(&stream_reader),
                  render_process_id, render_frame_id,
                  request_info->frame_tree_node_id(), callback));
 }
 
 void DownloadResourceHandler::OnReadyToRead() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  controller()->Resume();
+  Resume();
 }
 
 void DownloadResourceHandler::CancelRequest() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   const ResourceRequestInfoImpl* info = GetRequestInfo();
   ResourceDispatcherHostImpl::Get()->CancelRequest(
       info->GetChildID(),
       info->GetRequestID());
   // This object has been deleted.
@@ skipping 11 matching lines @@
                             " }",
                             request() ?
                                 request()->url().spec().c_str() :
                                 "<NULL request>",
                             info->GetChildID(),
                             info->GetRequestID(),
                             info->GetRouteID());
 }
 
 }  // namespace content