[Android WebView] Implement WebSettings.{get|set}CacheMode

android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.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 "android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.h"
 
 #include "android_webview/browser/aw_login_delegate.h"
 #include "android_webview/browser/aw_contents_io_thread_client.h"
 #include "android_webview/common/url_constants.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 19 matching lines @@
 void SetOnlyAllowLoadFromCache(
     net::URLRequest* request) {
   int load_flags = request->load_flags();
   load_flags &= ~(net::LOAD_BYPASS_CACHE &
                   net::LOAD_VALIDATE_CACHE &
                   net::LOAD_PREFERRING_CACHE);
   load_flags |= net::LOAD_ONLY_FROM_CACHE;
   request->set_load_flags(load_flags);
 }
 
-// May cancel this resource request based on result of Java callbacks.
-class MaybeCancelResourceThrottle : public content::ResourceThrottle {
+// Enqueries certain WebSettings values, sets up the resource request
+// accordingly.  May cancel the request.
+class ApplyWebSettingsResourceThrottle : public content::ResourceThrottle {
  public:
-  MaybeCancelResourceThrottle(int child_id,
-                              int route_id,
-                              net::URLRequest* request)
+  ApplyWebSettingsResourceThrottle(int child_id,
+                                   int route_id,
+                                   net::URLRequest* request)
       : child_id_(child_id),
         route_id_(route_id),
         request_(request) { }
   virtual void WillStartRequest(bool* defer) OVERRIDE;
 
   scoped_ptr<AwContentsIoThreadClient> GetIoThreadClient() {
     return AwContentsIoThreadClient::FromID(child_id_, route_id_);
   }
 
  private:
   int child_id_;
   int route_id_;
   net::URLRequest* request_;
 };
 
-void MaybeCancelResourceThrottle::WillStartRequest(bool* defer) {
+void ApplyWebSettingsResourceThrottle::WillStartRequest(bool* defer) {
   // If there is no IO thread client set at this point, use a
   // restrictive policy. This can happen for blocked popup
   // windows for example.
   // TODO(benm): Revert this to a DCHECK when the we support
   // pop up windows being created in the WebView, as at that
   // time we should always have an IoThreadClient at this
   // point (i.e., the one associated with the new popup).
   if (!GetIoThreadClient()) {
     controller()->CancelWithError(net::ERR_ACCESS_DENIED);
     return;
   }
 
+  AwContentsIoThreadClient::CacheMode cache_mode =
+      GetIoThreadClient()->GetCacheMode();
+  int load_flags = request_->load_flags();
+  switch(cache_mode) {
+    case AwContentsIoThreadClient::LOAD_CACHE_ELSE_NETWORK:
+      load_flags |= net::LOAD_PREFERRING_CACHE;
+      load_flags &= ~net::LOAD_VALIDATE_CACHE;
+      break;
+    case AwContentsIoThreadClient::LOAD_NO_CACHE:
+      load_flags |= net::LOAD_BYPASS_CACHE;
+      break;
+    case AwContentsIoThreadClient::LOAD_CACHE_ONLY:
+      load_flags |= net::LOAD_ONLY_FROM_CACHE;
+      break;
+    default:
+      break;
+  }
+  request_->set_load_flags(load_flags);

[boliu, 2012/11/20 20:00:09]

nit: Let's do better than existing code. I think the the 4 cache flags are
mutually exclusive, so can we make sure only one of them is set? Looking at this
code, I think it can work. See SetOnlyAllowLoadFromCache above.

[mnaganov (inactive), 2012/11/21 10:37:08]

Done. BTW, there was an error in SetOnlyAllowLoadFromCache, as AND-ing flags
effectively produces zero.

+
   // Part of implementation of WebSettings.allowContentAccess.
   if (request_->url().SchemeIs(android_webview::kContentScheme) &&
       GetIoThreadClient()->ShouldBlockContentUrls()) {
     controller()->CancelWithError(net::ERR_ACCESS_DENIED);
     return;
   }
 
   // Part of implementation of WebSettings.allowFileAccess.
   if (request_->url().SchemeIsFile() &&
       GetIoThreadClient()->ShouldBlockFileUrls()) {
     const GURL& url = request_->url();
     if (!url.has_path() ||
         // Application's assets and resources are always available.
         (url.path().find(android_webview::kAndroidResourcePath) != 0 &&
          url.path().find(android_webview::kAndroidAssetPath) != 0)) {
       controller()->CancelWithError(net::ERR_ACCESS_DENIED);
       return;
     }
   }
 
   if (GetIoThreadClient()->ShouldBlockNetworkLoads()) {
     if (request_->url().SchemeIs(chrome::kFtpScheme)) {
       controller()->CancelWithError(net::ERR_ACCESS_DENIED);
       return;
     }
     SetOnlyAllowLoadFromCache(request_);

[boliu, 2012/11/20 20:00:09]

Can you make sure the flags above are interacting correctly with this which also
sets flags?

[mnaganov (inactive), 2012/11/21 10:37:08]

Added a test. In fact, setting cache mode doesn't have any effect when network
loads are blocked (I verified with the legacy WebView for sure), so I moved the
new code under the else branch of network loads blocking.

   }
 }
 
 }  // namespace
 
 namespace android_webview {
 
 // static
 void AwResourceDispatcherHostDelegate::ResourceDispatcherHostCreated() {
   content::ResourceDispatcherHost::Get()->SetDelegate(
@@ skipping 10 matching lines @@
 void AwResourceDispatcherHostDelegate::RequestBeginning(
     net::URLRequest* request,
     content::ResourceContext* resource_context,
     appcache::AppCacheService* appcache_service,
     ResourceType::Type resource_type,
     int child_id,
     int route_id,
     bool is_continuation_of_transferred_request,
     ScopedVector<content::ResourceThrottle>* throttles) {
 
-  throttles->push_back(new MaybeCancelResourceThrottle(
+  throttles->push_back(new ApplyWebSettingsResourceThrottle(
       child_id, route_id, request));
 
   if (resource_type == ResourceType::MAIN_FRAME) {
     throttles->push_back(InterceptNavigationDelegate::CreateThrottleFor(
         request));
   }
 }
 
 bool AwResourceDispatcherHostDelegate::AcceptAuthRequest(
     net::URLRequest* request,
@@ skipping 11 matching lines @@
 bool AwResourceDispatcherHostDelegate::HandleExternalProtocol(const GURL& url,
                                                               int child_id,
                                                               int route_id) {
   // The AwURLRequestJobFactory implementation should ensure this method never
   // gets called.
   NOTREACHED();
   return false;
 }
 
 }