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

content/browser/download/download_resource_handler.cc

Index: content/browser/download/download_resource_handler.cc
diff --git a/content/browser/download/download_resource_handler.cc b/content/browser/download/download_resource_handler.cc
index 5cc4ee8123ec222aca709871feec52415e2252ae..e4b82bf50be6e8178e2df7a8d2d207148b7306af 100644
--- a/content/browser/download/download_resource_handler.cc
+++ b/content/browser/download/download_resource_handler.cc
@@ -7,34 +7,22 @@
 #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/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_request_info_impl.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 "content/public/common/resource_response.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 {
 
@@ -45,17 +33,6 @@ struct DownloadResourceHandler::DownloadTabInfo {
 
 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
 // DownloadResourceHandler members from the UI thread.
 static void StartOnUIThread(
@@ -65,7 +42,8 @@ static void StartOnUIThread(
     const DownloadUrlParameters::OnStartedCallback& started_cb) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  DownloadManager* download_manager = info->request_handle.GetDownloadManager();
+  DownloadManager* download_manager =
+      info->request_handle->GetDownloadManager();
   if (!download_manager) {
     // NULL in unittests or if the page closed right after starting the
     // download.
@@ -104,8 +82,6 @@ void DeleteOnUIThread(
 
 }  // namespace
 
-const int DownloadResourceHandler::kDownloadByteStreamSize = 100 * 1024;
-
 DownloadResourceHandler::DownloadResourceHandler(
     uint32 id,
     net::URLRequest* request,
@@ -114,15 +90,11 @@ DownloadResourceHandler::DownloadResourceHandler(
     : ResourceHandler(request),
       download_id_(id),
       started_cb_(started_cb),
-      save_info_(save_info.Pass()),
       tab_info_(new DownloadTabInfo()),
-      last_buffer_size_(0),
-      bytes_read_(0),
-      pause_count_(0),
-      was_deferred_(false),
-      on_response_started_called_(false) {
-  RecordDownloadCount(UNTHROTTLED_COUNT);
-
+      core_(request,
+            save_info.Pass(),
+            base::Bind(&DownloadResourceHandler::OnCoreReadyToRead,
+                       base::Unretained(this))) {
   // Do UI thread initialization for tab_info_ asap after
   // DownloadResourceHandler creation since the tab could be navigated
   // before StartOnUIThread gets called.  This is safe because deletion
@@ -137,9 +109,19 @@ DownloadResourceHandler::DownloadResourceHandler(
                                        request_info->GetRequestID(),
                                        request_info->frame_tree_node_id()),
                  tab_info_.get()));
-  power_save_blocker_ = PowerSaveBlocker::Create(
-      PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension,
-      PowerSaveBlocker::kReasonOther, "Download in progress");
+}
+
+DownloadResourceHandler::~DownloadResourceHandler() {
+  // 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(DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED);
+
+  if (tab_info_) {
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&DeleteOnUIThread, base::Passed(&tab_info_)));
+  }
 }
 
 bool DownloadResourceHandler::OnRequestRedirected(
@@ -153,127 +135,39 @@ bool DownloadResourceHandler::OnRequestRedirected(
 bool DownloadResourceHandler::OnResponseStarted(
     ResourceResponse* response,
     bool* defer) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  // There can be only one (call)
-  DCHECK(!on_response_started_called_);
-  on_response_started_called_ = true;
-
-  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);
+  scoped_ptr<DownloadCreateInfo> create_info;
+  scoped_ptr<ByteStreamReader> stream_reader;
 
-  // 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 =
-      response->head.content_length > 0 ? response->head.content_length : 0;
+  core_.OnResponseStarted(&create_info, &stream_reader);
 
   const ResourceRequestInfoImpl* request_info = GetRequestInfo();
-
-  // Deleted in DownloadManager.
-  scoped_ptr<DownloadCreateInfo> info(
-      new DownloadCreateInfo(base::Time::Now(),
-                             content_length,
-                             request()->net_log(),
-                             request_info->HasUserGesture(),
-                             request_info->GetPageTransition(),
-                             save_info_.Pass()));
-
-  // 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);
-  stream_writer_->RegisterCallback(
-      base::Bind(&DownloadResourceHandler::ResumeRequest, AsWeakPtr()));
-
-  info->download_id = download_id_;
-  info->url_chain = request()->url_chain();
-  info->referrer_url = GURL(request()->referrer());
-  info->mime_type = response->head.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);
-  }
-  RecordDownloadMimeType(info->mime_type);
-  RecordDownloadContentDisposition(info->content_disposition);
-
-  info->request_handle = DownloadRequestHandle(
+  create_info->download_id = download_id_;
+  create_info->has_user_gesture = request_info->HasUserGesture();
+  create_info->transition_type = request_info->GetPageTransition();
+  create_info->request_handle.reset(new DownloadRequestHandle(
       AsWeakPtr(), request_info->GetChildID(), request_info->GetRouteID(),
-      request_info->GetRequestID(), request_info->frame_tree_node_id());
-
-  // 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.
-      if (!headers->EnumerateHeader(NULL, "Last-Modified",
-                                    &info->last_modified))
-        info->last_modified.clear();
-      if (!headers->EnumerateHeader(NULL, "ETag", &info->etag))
-        info->etag.clear();
-    }
+      request_info->GetRequestID(), request_info->frame_tree_node_id()));
 
-    int status = headers->response_code();
-    if (2 == status / 100  && status != net::HTTP_PARTIAL_CONTENT) {
-      // Success & not range response; if we asked for a range, we didn't
-      // get it--reset the file pointers to reflect that.
-      info->save_info->offset = 0;
-      info->save_info->hash_state = "";
-    }
-
-    if (!headers->GetMimeType(&info->original_mime_type))
-      info->original_mime_type.clear();
-  }
-
-  // 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();
+  // The MIME type in ResourceResponse is the product of
+  // MimeTypeResourceHandler.
+  create_info->mime_type = response->head.mime_type;
 
   BrowserThread::PostTask(
       BrowserThread::UI, FROM_HERE,
-      base::Bind(&StartOnUIThread,
-                 base::Passed(&info),
-                 base::Passed(&tab_info_),
-                 base::Passed(&stream_reader),
-                 // 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();
-
+      base::Bind(&StartOnUIThread, base::Passed(&create_info),
+                 base::Passed(&tab_info_), base::Passed(&stream_reader),
+                 base::ResetAndReturn(&started_cb_)));
   return true;
 }
 
 void DownloadResourceHandler::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();
+  BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
+                          base::Bind(base::ResetAndReturn(&started_cb_),
+                                     nullptr, interrupt_reason));
 }
 
 bool DownloadResourceHandler::OnWillStart(const GURL& url, bool* defer) {
@@ -290,175 +184,20 @@ bool DownloadResourceHandler::OnBeforeNetworkStart(const GURL& url,
 bool DownloadResourceHandler::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());
-
-  *buf_size = min_size < 0 ? kReadBufSize : min_size;
-  last_buffer_size_ = *buf_size;
-  read_buffer_ = new net::IOBuffer(*buf_size);
-  *buf = read_buffer_.get();
-  return true;
+  return core_.OnWillRead(buf, buf_size, min_size);
 }
 
 // Pass the buffer to the download file writer.
 bool DownloadResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-  DCHECK(read_buffer_.get());
-
-  base::TimeTicks now(base::TimeTicks::Now());
-  if (!last_read_time_.is_null()) {
-    double seconds_since_last_read = (now - last_read_time_).InSecondsF();
-    if (now == last_read_time_)
-      // Use 1/10 ms as a "very small number" so that we avoid
-      // divide-by-zero error and still record a very high potential bandwidth.
-      seconds_since_last_read = 0.00001;
-
-    double actual_bandwidth = (bytes_read)/seconds_since_last_read;
-    double potential_bandwidth = last_buffer_size_/seconds_since_last_read;
-    RecordBandwidth(actual_bandwidth, potential_bandwidth);
-  }
-  last_read_time_ = now;
-
-  if (!bytes_read)
-    return true;
-  bytes_read_ += bytes_read;
-  DCHECK(read_buffer_.get());
-
-  // Take the data ship it down the stream.  If the stream is full, pause the
-  // request; the stream callback will resume it.
-  if (!stream_writer_->Write(read_buffer_, bytes_read)) {
-    PauseRequest();
-    *defer = was_deferred_ = true;
-    last_stream_pause_time_ = now;
-  }
-
-  read_buffer_ = NULL;  // Drop our reference.
-
-  if (pause_count_ > 0)
-    *defer = was_deferred_ = true;
-
-  return true;
+  return core_.OnReadCompleted(bytes_read, defer);
 }
 
 void DownloadResourceHandler::OnResponseCompleted(
     const net::URLRequestStatus& status,
     const std::string& security_info,
     bool* defer) {
-  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 ||
-      // Note cancels as failures too.
-      status.status() == net::URLRequestStatus::CANCELED) {
-    error_code = static_cast<net::Error>(status.error());  // Normal case.
-    // Make sure that at least the fact of failure comes through.
-    if (error_code == net::OK)
-      error_code = net::ERR_FAILED;
-  }
-
-  // ERR_CONTENT_LENGTH_MISMATCH and ERR_INCOMPLETE_CHUNKED_ENCODING are
-  // allowed since a number of servers in the wild close the connection too
-  // early by mistake. Other browsers - IE9, Firefox 11.0, and Safari 5.1.4 -
-  // treat downloads as complete in both cases, so we follow their lead.
-  if (error_code == net::ERR_CONTENT_LENGTH_MISMATCH ||
-      error_code == net::ERR_INCOMPLETE_CHUNKED_ENCODING) {
-    error_code = net::OK;
-  }
-  DownloadInterruptReason reason =
-      ConvertNetErrorToInterruptReason(
-        error_code, DOWNLOAD_INTERRUPT_FROM_NETWORK);
-
-  if (status.status() == net::URLRequestStatus::CANCELED &&
-      status.error() == net::ERR_ABORTED) {
-    // CANCELED + ERR_ABORTED == something outside of the network
-    // stack cancelled the request.  There aren't that many things that
-    // could do this to a download request (whose lifetime is separated from
-    // the tab from which it came).  We map this to USER_CANCELLED as the
-    // case we know about (system suspend because of laptop close) corresponds
-    // to a user action.
-    // TODO(ahendrickson) -- Find a better set of codes to use here, as
-    // CANCELED/ERR_ABORTED can occur for reasons other than user cancel.
-    if (net::IsCertStatusError(request()->ssl_info().cert_status))
-      reason = DOWNLOAD_INTERRUPT_REASON_SERVER_CERT_PROBLEM;
-    else
-      reason = DOWNLOAD_INTERRUPT_REASON_USER_CANCELED;
-  }
-
-  if (status.is_success() &&
-      reason == DOWNLOAD_INTERRUPT_REASON_NONE &&
-      request()->response_headers()) {
-    // Handle server's response codes.
-    switch(response_code) {
-      case -1:                          // Non-HTTP request.
-      case net::HTTP_OK:
-      case net::HTTP_CREATED:
-      case net::HTTP_ACCEPTED:
-      case net::HTTP_NON_AUTHORITATIVE_INFORMATION:
-      case net::HTTP_RESET_CONTENT:
-      case net::HTTP_PARTIAL_CONTENT:
-        // Expected successful codes.
-        break;
-      case net::HTTP_NO_CONTENT:
-      case net::HTTP_NOT_FOUND:
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_BAD_CONTENT;
-        break;
-      case net::HTTP_REQUESTED_RANGE_NOT_SATISFIABLE:
-        // Retry by downloading from the start automatically:
-        // If we haven't received data when we get this error, we won't.
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_NO_RANGE;
-        break;
-      case net::HTTP_UNAUTHORIZED:
-        // Server didn't authorize this request.
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_UNAUTHORIZED;
-        break;
-      case net::HTTP_FORBIDDEN:
-        // Server forbids access to this resource.
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_FORBIDDEN;
-        break;
-      default:    // All other errors.
-        // Redirection and informational codes should have been handled earlier
-        // in the stack.
-        DCHECK_NE(3, response_code / 100);
-        DCHECK_NE(1, response_code / 100);
-        reason = DOWNLOAD_INTERRUPT_REASON_SERVER_FAILED;
-        break;
-    }
-  }
-
-  std::string accept_ranges;
-  bool has_strong_validators = false;
-  if (request()->response_headers()) {
-    request()->response_headers()->EnumerateHeader(
-        NULL, "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(NULL, 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_ = NULL;
+  DownloadInterruptReason result = core_.OnResponseCompleted(status);
+  CallStartedCB(result);
 }
 
 void DownloadResourceHandler::OnDataDownloaded(int bytes_downloaded) {
@@ -466,28 +205,15 @@ void DownloadResourceHandler::OnDataDownloaded(int bytes_downloaded) {
 }
 
 void DownloadResourceHandler::PauseRequest() {
-  DCHECK_CURRENTLY_ON(BrowserThread::IO);
-
-  ++pause_count_;
+  core_.PauseRequest();
 }
 
 void DownloadResourceHandler::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();
-  }
+  core_.ResumeRequest();
+}
 
+void DownloadResourceHandler::OnCoreReadyToRead() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
   controller()->Resume();
 }
 
@@ -519,28 +245,4 @@ std::string DownloadResourceHandler::DebugString() const {
                             info->GetRouteID());
 }
 
-DownloadResourceHandler::~DownloadResourceHandler() {
-  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(NULL, DOWNLOAD_INTERRUPT_REASON_NETWORK_FAILED);
-
-  // Remove output stream callback if a stream exists.
-  if (stream_writer_)
-    stream_writer_->RegisterCallback(base::Closure());
-
-  // tab_info_ must be destroyed on UI thread, since
-  // InitializeDownloadTabInfoOnUIThread might still be using it.
-  if (tab_info_.get()) {
-    BrowserThread::PostTask(
-        BrowserThread::UI, FROM_HERE,
-        base::Bind(&DeleteOnUIThread, base::Passed(&tab_info_)));
-  }
-
-  UMA_HISTOGRAM_TIMES("SB2.DownloadDuration",
-                      base::TimeTicks::Now() - download_start_time_);
-}
-
 }  // namespace content