[Downloads] Factor out request handling logic between DRH and UD.

content/browser/download/download_request_core.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_request_core.h"
 
 #include <string>
 
 #include "base/bind.h"
+#include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/stringprintf.h"
 #include "base/thread_task_runner_handle.h"
 #include "content/browser/byte_stream.h"
 #include "content/browser/download/download_create_info.h"
 #include "content/browser/download/download_interrupt_reasons_impl.h"
 #include "content/browser/download/download_manager_impl.h"
+#include "content/browser/download/download_request_handle.h"
 #include "content/browser/download/download_stats.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager_delegate.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/power_save_blocker.h"
 #include "content/public/browser/web_contents.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_response_headers.h"
 #include "net/http/http_status_code.h"
 #include "net/url_request/url_request_context.h"
 
 namespace content {
 
-namespace {
-
-void CallStartedCBOnUIThread(
-    const DownloadUrlParameters::OnStartedCallback& started_cb,
-    DownloadItem* item,
-    DownloadInterruptReason interrupt_reason) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-
-  if (started_cb.is_null())
-    return;
-  started_cb.Run(item, interrupt_reason);
-}
-
-// Static function in order to prevent any accidental accesses to
-// DownloadRequestCore members from the UI thread.
-static void StartOnUIThread(
-    scoped_ptr<DownloadCreateInfo> info,
-    scoped_ptr<ByteStreamReader> stream,
-    base::WeakPtr<DownloadManager> download_manager,
-    const DownloadUrlParameters::OnStartedCallback& started_cb) {
-  DCHECK_CURRENTLY_ON(BrowserThread::UI);
-
-  if (!download_manager) {
-    // nullptr in unittests or if the page closed right after starting the
-    // download.
-    if (!started_cb.is_null())
-      started_cb.Run(nullptr, DOWNLOAD_INTERRUPT_REASON_USER_CANCELED);
-
-    // |stream| gets deleted on non-FILE thread, but it's ok since
-    // we're not using stream_writer_ yet.
-
-    return;
-  }
-
-  download_manager->StartDownload(info.Pass(), stream.Pass(), started_cb);
-}
-
-}  // namespace
-
 const int DownloadRequestCore::kDownloadByteStreamSize = 100 * 1024;
 
 DownloadRequestCore::DownloadRequestCore(
-    uint32 id,
     net::URLRequest* request,
-    const DownloadUrlParameters::OnStartedCallback& started_cb,
     scoped_ptr<DownloadSaveInfo> save_info,
-    base::WeakPtr<DownloadManagerImpl> download_manager)
-    : request_(request),
-      download_id_(id),
-      started_cb_(started_cb),
-      save_info_(save_info.Pass()),
+    const base::Closure& on_ready_to_read_callback)
+    : on_ready_to_read_callback_(on_ready_to_read_callback),
+      request_(request),
+      save_info_(std::move(save_info)),
       last_buffer_size_(0),
       bytes_read_(0),
       pause_count_(0),
-      was_deferred_(false),
-      on_response_started_called_(false),
-      download_manager_(download_manager) {
+      was_deferred_(false) {
+  DCHECK(request_);
+  DCHECK(save_info_);
+  DCHECK(!on_ready_to_read_callback_.is_null());
   RecordDownloadCount(UNTHROTTLED_COUNT);
-
   power_save_blocker_ = PowerSaveBlocker::Create(
       PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension,
       PowerSaveBlocker::kReasonOther, "Download in progress");
 }
 
 DownloadRequestCore::~DownloadRequestCore() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-
-  // This won't do anything if the callback was called before.
-  // If it goes through, it will likely be because OnWillStart() returned
-  // false somewhere in the chain of resource handlers.
-  CallStartedCB(nullptr, DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED);
-
   // Remove output stream callback if a stream exists.
   if (stream_writer_)
     stream_writer_->RegisterCallback(base::Closure());
 
   UMA_HISTOGRAM_TIMES("SB2.DownloadDuration",
                       base::TimeTicks::Now() - download_start_time_);
 }
 
 // Send the download creation information to the download thread.
-bool DownloadRequestCore::OnResponseStarted() {
+void DownloadRequestCore::OnResponseStarted(
+    scoped_ptr<DownloadCreateInfo>* create_info,
+    scoped_ptr<ByteStreamReader>* stream_reader) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  // There can be only one (call)
-  DCHECK(!on_response_started_called_);
-  on_response_started_called_ = true;
-
+  DCHECK(save_info_);
   DVLOG(20) << __FUNCTION__ << "()" << DebugString();
   download_start_time_ = base::TimeTicks::Now();
 
   // If it's a download, we don't want to poison the cache with it.
   request()->StopCaching();
 
   // Lower priority as well, so downloads don't contend for resources
   // with main frames.
   request()->SetPriority(net::IDLE);
 
   // If the content-length header is not present (or contains something other
   // than numbers), the incoming content_length is -1 (unknown size).
   // Set the content length to 0 to indicate unknown size to DownloadManager.
   int64 content_length = request()->GetExpectedContentSize() > 0
                              ? request()->GetExpectedContentSize()
                              : 0;
 
   // Deleted in DownloadManager.
-  scoped_ptr<DownloadCreateInfo> info(new DownloadCreateInfo(
-      base::Time::Now(), content_length, request()->net_log(), false,
-      ui::PAGE_TRANSITION_LINK, save_info_.Pass()));
+  scoped_ptr<DownloadCreateInfo> info(
+      new DownloadCreateInfo(base::Time::Now(), content_length,
+                             request()->net_log(), std::move(save_info_)));
 
   // Create the ByteStream for sending data to the download sink.
-  scoped_ptr<ByteStreamReader> stream_reader;
   CreateByteStream(
       base::ThreadTaskRunnerHandle::Get(),
       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
-      kDownloadByteStreamSize, &stream_writer_, &stream_reader);
+      kDownloadByteStreamSize, &stream_writer_, stream_reader);
   stream_writer_->RegisterCallback(
       base::Bind(&DownloadRequestCore::ResumeRequest, AsWeakPtr()));
 
-  info->download_id = download_id_;
   info->url_chain = request()->url_chain();
   info->referrer_url = GURL(request()->referrer());
   string mime_type;
   request()->GetMimeType(&mime_type);
   info->mime_type = mime_type;
   info->remote_address = request()->GetSocketAddress().host();
   if (request()->response_headers()) {
     // Grab the first content-disposition header.  There may be more than one,
     // though as of this writing, the network stack ensures if there are, they
     // are all duplicates.
     request()->response_headers()->EnumerateHeader(
-        nullptr, "content-disposition", &info->content_disposition);
+        nullptr, "Content-Disposition", &info->content_disposition);
   }
   RecordDownloadMimeType(info->mime_type);
   RecordDownloadContentDisposition(info->content_disposition);
 
   // Get the last modified time and etag.
   const net::HttpResponseHeaders* headers = request()->response_headers();
   if (headers) {
     if (headers->HasStrongValidators()) {
       // If we don't have strong validators as per RFC 2616 section 13.3.3, then
       // we neither store nor use them for range requests.
@@ skipping 17 matching lines @@
   }
 
   // Blink verifies that the requester of this download is allowed to set a
   // suggested name for the security origin of the downlaod URL. However, this
   // assumption doesn't hold if there were cross origin redirects. Therefore,
   // clear the suggested_name for such requests.
   if (info->url_chain.size() > 1 &&
       info->url_chain.front().GetOrigin() != info->url_chain.back().GetOrigin())
     info->save_info->suggested_name.clear();
 
-  BrowserThread::PostTask(
-      BrowserThread::UI, FROM_HERE,
-      base::Bind(&StartOnUIThread, base::Passed(&info),
-                 base::Passed(&stream_reader), download_manager_,
-                 // Pass to StartOnUIThread so that variable
-                 // access is always on IO thread but function
-                 // is called on UI thread.
-                 started_cb_));
-  // Guaranteed to be called in StartOnUIThread
-  started_cb_.Reset();
-
-  return true;
-}
-
-void DownloadRequestCore::CallStartedCB(
-    DownloadItem* item,
-    DownloadInterruptReason interrupt_reason) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  if (started_cb_.is_null())
-    return;
-  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
-                          base::Bind(&CallStartedCBOnUIThread, started_cb_,
-                                     item, interrupt_reason));
-  started_cb_.Reset();
+  info.swap(*create_info);
 }
 
 // Create a new buffer, which will be handed to the download thread for file
 // writing and deletion.
 bool DownloadRequestCore::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
                                      int* buf_size,
                                      int min_size) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK(buf && buf_size);
   DCHECK(!read_buffer_.get());
@@ skipping 38 matching lines @@
   }
 
   read_buffer_ = NULL;  // Drop our reference.
 
   if (pause_count_ > 0)
     *defer = was_deferred_ = true;
 
   return true;
 }
 
-void DownloadRequestCore::OnResponseCompleted(
+DownloadInterruptReason DownloadRequestCore::OnResponseCompleted(
     const net::URLRequestStatus& status) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   int response_code = status.is_success() ? request()->GetResponseCode() : 0;
   DVLOG(20) << __FUNCTION__ << "()" << DebugString()
             << " status.status() = " << status.status()
             << " status.error() = " << status.error()
             << " response_code = " << response_code;
 
   net::Error error_code = net::OK;
   if (status.status() == net::URLRequestStatus::FAILED ||
@@ skipping 77 matching lines @@
   if (request()->response_headers()) {
     request()->response_headers()->EnumerateHeader(nullptr, "Accept-Ranges",
                                                    &accept_ranges);
     has_strong_validators =
         request()->response_headers()->HasStrongValidators();
   }
   RecordAcceptsRanges(accept_ranges, bytes_read_, has_strong_validators);
   RecordNetworkBlockage(base::TimeTicks::Now() - download_start_time_,
                         total_pause_time_);
 
-  CallStartedCB(nullptr, reason);
-
   // Send the info down the stream.  Conditional is in case we get
   // OnResponseCompleted without OnResponseStarted.
   if (stream_writer_)
     stream_writer_->Close(reason);
 
   // If the error mapped to something unknown, record it so that
   // we can drill down.
   if (reason == DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED) {
     UMA_HISTOGRAM_SPARSE_SLOWLY("Download.MapErrorNetworkFailed",
                                 std::abs(status.error()));
   }
 
   stream_writer_.reset();  // We no longer need the stream.
   read_buffer_ = nullptr;
+
+  return reason;
 }
 
 void DownloadRequestCore::PauseRequest() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   ++pause_count_;
 }
 
 void DownloadRequestCore::ResumeRequest() {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
   DCHECK_LT(0, pause_count_);
 
   --pause_count_;
 
   if (!was_deferred_)
     return;
   if (pause_count_ > 0)
     return;
 
   was_deferred_ = false;
   if (!last_stream_pause_time_.is_null()) {
     total_pause_time_ += (base::TimeTicks::Now() - last_stream_pause_time_);
     last_stream_pause_time_ = base::TimeTicks();
   }
 
-  downloader_->ResumeReading();
+  on_ready_to_read_callback_.Run();
 }
 
 std::string DownloadRequestCore::DebugString() const {
   return base::StringPrintf(
       "{"
       " url_ = "
       "\"%s\""
       " }",
       request() ? request()->url().spec().c_str() : "<NULL request>");
 }
 
 }  // namespace content