Move MimeTypeResourceHandler before ThrottlingResourceHandler

content/browser/loader/replacing_resource_handler.cc

Index: content/browser/loader/replacing_resource_handler.cc
diff --git a/content/browser/loader/replacing_resource_handler.cc b/content/browser/loader/replacing_resource_handler.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d1ecbf132b0a287e73d3beb682f45654c1014981
--- /dev/null
+++ b/content/browser/loader/replacing_resource_handler.cc
@@ -0,0 +1,317 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.

[mmenke, 2016/06/09 18:09:29]

Weird that git isn't picking up that this file was forked from
mime_type_resource_handler.  Could you try turning down the similarity
threshold?  Makes review easier.

[clamy, 2016/06/21 16:14:15]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/loader/replacing_resource_handler.h"
+
+#include <utility>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/location.h"
+#include "base/logging.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/single_thread_task_runner.h"
+#include "base/strings/string_util.h"
+#include "base/threading/thread_task_runner_handle.h"
+#include "components/mime_util/mime_util.h"
+#include "content/browser/download/download_resource_handler.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/browser/loader/stream_resource_handler.h"
+#include "content/public/browser/content_browser_client.h"
+#include "content/public/browser/download_item.h"
+#include "content/public/browser/download_save_info.h"
+#include "content/public/browser/download_url_parameters.h"
+#include "content/public/browser/plugin_service.h"
+#include "content/public/browser/resource_context.h"
+#include "content/public/browser/resource_dispatcher_host_delegate.h"
+#include "content/public/common/resource_response.h"
+#include "content/public/common/webplugininfo.h"
+#include "net/base/io_buffer.h"
+#include "net/base/mime_sniffer.h"

[mattm, 2016/06/09 22:55:32]

not used here?

[clamy, 2016/06/21 16:14:15]

Done.

+#include "net/base/mime_util.h"
+#include "net/http/http_content_disposition.h"
+#include "net/http/http_response_headers.h"
+
+namespace content {
+
+ReplacingResourceHandler::ReplacingResourceHandler(
+    std::unique_ptr<ResourceHandler> next_handler,
+    ResourceDispatcherHostImpl* host,
+    PluginService* plugin_service,
+    net::URLRequest* request)
+    : LayeredResourceHandler(request, std::move(next_handler)),
+      state_(State::STARTING),
+      host_(host),
+#if defined(ENABLE_PLUGINS)
+      plugin_service_(plugin_service),
+#endif
+      switched_handler_(false),
+      must_download_(false),
+      must_download_is_set_(false),
+      bytes_read_(0),
+      weak_ptr_factory_(this) {
+}
+
+ReplacingResourceHandler::~ReplacingResourceHandler() {}
+
+bool ReplacingResourceHandler::OnResponseStarted(ResourceResponse* response,
+                                                 bool* defer) {
+  if (response->head.headers.get() &&
+      response->head.headers->response_code() == 304) {
+    return true;

[mmenke, 2016/06/09 18:09:29]

BUG:  This should be passed through to the next handler, and state should be set
to State::CHOICE_MADE.  Should have a test for that case.

[clamy, 2016/06/21 16:14:15]

Done.

+  }
+
+  response_ = response;
+
+  state_ = State::WAITING_FOR_NEW_HANDLER;
+
+  return MakeHandlerChoice(defer);
+}
+
+bool ReplacingResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
+                                          int* buf_size,
+                                          int min_size) {
+  if (state_ == State::CHOICE_MADE)
+    return next_handler_->OnWillRead(buf, buf_size, min_size);
+
+  DCHECK_EQ(State::STARTING, state_);
+  DCHECK_EQ(-1, min_size);
+
+  if (!next_handler_->OnWillRead(buf, buf_size, min_size))
+    return false;
+
+  read_buffer_ = *buf;
+  return true;
+}
+
+bool ReplacingResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
+  if (state_ == State::CHOICE_MADE)
+    return next_handler_->OnReadCompleted(bytes_read, defer);
+
+  DCHECK(state_ == State::WAITING_FOR_BUFFER_COPY);

[mmenke, 2016/06/09 18:09:29]

DCHECK_EQ

[clamy, 2016/06/21 16:14:15]

Done.

+  bytes_read_ += bytes_read;
+  if (!CopyReadBufferToNextHandler())
+    return false;
+
+  return next_handler_->OnReadCompleted(bytes_read, defer);
+}
+
+bool ReplacingResourceHandler::MakeHandlerChoice(bool* defer) {
+  if (!SelectNextHandler(defer))
+    return false;
+
+  if (*defer)
+    return true;
+
+  if (!next_handler_->OnResponseStarted(response_.get(), defer))
+    return false;
+
+  state_ = read_buffer_ && switched_handler_ ? State::WAITING_FOR_BUFFER_COPY
+                                             : State::CHOICE_MADE;
+  return true;
+}
+
+bool ReplacingResourceHandler::SelectPluginHandler(bool* defer,
+                                                   bool* handled_by_plugin) {
+  *handled_by_plugin = false;
+#if defined(ENABLE_PLUGINS)
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+  bool allow_wildcard = false;
+  bool stale;
+  WebPluginInfo plugin;
+  bool has_plugin = plugin_service_->GetPluginInfo(
+      info->GetChildID(), info->GetRenderFrameID(), info->GetContext(),
+      request()->url(), GURL(), response_->head.mime_type, allow_wildcard,
+      &stale, &plugin, NULL);
+
+  if (stale) {
+    // Refresh the plugins asynchronously.
+    plugin_service_->GetPlugins(
+        base::Bind(&ReplacingResourceHandler::OnPluginsLoaded,
+                   weak_ptr_factory_.GetWeakPtr()));
+    request()->LogBlockedBy("ReplacingResourceHandler");
+    *defer = true;
+    return true;
+  }
+
+  if (has_plugin && plugin.type != WebPluginInfo::PLUGIN_TYPE_BROWSER_PLUGIN) {
+    *handled_by_plugin = true;
+    return true;
+  }
+
+  // Attempt to intercept the request as a stream.
+  base::FilePath plugin_path;
+  if (has_plugin)
+    plugin_path = plugin.path;
+  std::string payload;
+  std::unique_ptr<ResourceHandler> handler(host_->MaybeInterceptAsStream(
+      plugin_path, request(), response_.get(), &payload));
+  if (handler) {
+    *handled_by_plugin = true;
+    return UseAlternateNextHandler(std::move(handler), payload);
+  }
+#endif
+  return true;
+}
+
+bool ReplacingResourceHandler::SelectNextHandler(bool* defer) {
+  DCHECK(!response_->head.mime_type.empty());
+
+  ResourceRequestInfoImpl* info = GetRequestInfo();
+  const std::string& mime_type = response_->head.mime_type;
+
+  // https://crbug.com/568184 - Temporary hack to track servers that aren't
+  // setting Content-Disposition when sending x-x509-user-cert and expecting
+  // the browser to automatically install certificates; this is being
+  // deprecated and will be removed upon full <keygen> removal.
+  if (mime_type == "application/x-x509-user-cert") {
+    UMA_HISTOGRAM_BOOLEAN(
+        "UserCert.ContentDisposition",
+        response_->head.headers->HasHeader("Content-Disposition"));
+  }
+
+  // Allow requests for object/embed tags to be intercepted as streams.
+  if (info->GetResourceType() == content::RESOURCE_TYPE_OBJECT) {
+    DCHECK(!info->allow_download());
+
+    bool handled_by_plugin;
+    if (!SelectPluginHandler(defer, &handled_by_plugin))
+      return false;
+    if (handled_by_plugin || *defer)
+      return true;
+  }
+
+  if (!info->allow_download())
+    return true;
+
+  // info->allow_download() == true implies
+  // info->GetResourceType() == RESOURCE_TYPE_MAIN_FRAME or
+  // info->GetResourceType() == RESOURCE_TYPE_SUB_FRAME.
+  DCHECK(info->GetResourceType() == RESOURCE_TYPE_MAIN_FRAME ||
+         info->GetResourceType() == RESOURCE_TYPE_SUB_FRAME);
+
+  bool must_download = MustDownload();
+  if (!must_download) {
+    if (mime_util::IsSupportedMimeType(mime_type))
+      return true;
+
+    bool handled_by_plugin;
+    if (!SelectPluginHandler(defer, &handled_by_plugin))
+      return false;
+    if (handled_by_plugin || *defer)
+      return true;
+  }
+
+  // Install download handler
+  info->set_is_download(true);
+  std::unique_ptr<ResourceHandler> handler(
+      host_->CreateResourceHandlerForDownload(request(),
+                                              true,  // is_content_initiated
+                                              must_download));
+  return UseAlternateNextHandler(std::move(handler), std::string());
+}
+
+bool ReplacingResourceHandler::UseAlternateNextHandler(
+    std::unique_ptr<ResourceHandler> new_handler,
+    const std::string& payload_for_old_handler) {
+  if (response_->head.headers.get() &&  // Can be NULL if FTP.
+      response_->head.headers->response_code() / 100 != 2) {
+    // The response code indicates that this is an error page, but we don't
+    // know how to display the content.  We follow Firefox here and show our
+    // own error page instead of triggering a download.
+    // TODO(abarth): We should abstract the response_code test, but this kind
+    //               of check is scattered throughout our codebase.
+    request()->CancelWithError(net::ERR_INVALID_RESPONSE);
+    return false;
+  }
+
+  // Inform the original ResourceHandler that this will be handled entirely by
+  // the new ResourceHandler.
+  // TODO(darin): We should probably check the return values of these.
+  bool defer_ignored = false;
+  next_handler_->OnResponseStarted(response_.get(), &defer_ignored);
+  // Although deferring OnResponseStarted is legal, the only downstream handler
+  // which does so is CrossSiteResourceHandler. Cross-site transitions should
+  // not trigger when switching handlers.
+  DCHECK(!defer_ignored);
+  if (payload_for_old_handler.empty()) {
+    net::URLRequestStatus status(net::URLRequestStatus::CANCELED,
+                                 net::ERR_ABORTED);
+    next_handler_->OnResponseCompleted(status, std::string(), &defer_ignored);
+    DCHECK(!defer_ignored);
+  } else {
+    scoped_refptr<net::IOBuffer> buf;
+    int size = 0;
+    next_handler_->OnWillRead(&buf, &size, -1);
+    CHECK_GE(size, static_cast<int>(payload_for_old_handler.length()));
+    memcpy(buf->data(), payload_for_old_handler.c_str(),
+           payload_for_old_handler.length());
+    next_handler_->OnReadCompleted(payload_for_old_handler.length(),
+                                   &defer_ignored);
+    DCHECK(!defer_ignored);
+
+    net::URLRequestStatus status(net::URLRequestStatus::SUCCESS, 0);
+    next_handler_->OnResponseCompleted(status, std::string(), &defer_ignored);
+    DCHECK(!defer_ignored);
+  }
+
+  // This is handled entirely within the new ResourceHandler, so just reset the
+  // original ResourceHandler.
+  next_handler_ = std::move(new_handler);
+  next_handler_->SetController(controller());
+
+  switched_handler_ = true;
+
+  return true;
+}
+
+bool ReplacingResourceHandler::MustDownload() {
+  if (must_download_is_set_)
+    return must_download_;
+
+  must_download_is_set_ = true;
+
+  std::string disposition;
+  request()->GetResponseHeaderByName("content-disposition", &disposition);
+  if (!disposition.empty() &&
+      net::HttpContentDisposition(disposition, std::string()).is_attachment()) {
+    must_download_ = true;
+  } else if (host_->delegate() &&
+             host_->delegate()->ShouldForceDownloadResource(
+                 request()->url(), response_->head.mime_type)) {
+    must_download_ = true;
+  } else {
+    must_download_ = false;
+  }
+
+  return must_download_;
+}
+
+void ReplacingResourceHandler::OnPluginsLoaded(
+    const std::vector<WebPluginInfo>& plugins) {
+  request()->LogUnblocked();
+  bool defer = false;
+  if (!MakeHandlerChoice(&defer)) {
+    controller()->Cancel();
+  } else if (!defer) {
+    controller()->Resume();
+  }
+}
+
+bool ReplacingResourceHandler::CopyReadBufferToNextHandler() {
+  DCHECK(read_buffer_.get());
+  scoped_refptr<net::IOBuffer> buf;
+  int buf_len = 0;
+  if (!next_handler_->OnWillRead(&buf, &buf_len, bytes_read_))
+    return false;
+
+  CHECK((buf_len >= bytes_read_) && (bytes_read_ >= 0));
+  memcpy(buf->data(), read_buffer_->data(), bytes_read_);
+  state_ = State::CHOICE_MADE;
+  return true;
+}
+
+}  // namespace content