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

android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc

Index: android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
diff --git a/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc b/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
index b24eb2b56eac50e61bccdadb308a07a74515d6c0..fb5106066a38ceb29343eab595901cccea857fc8 100644
--- a/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
+++ b/android_webview/browser/renderer_host/aw_resource_dispatcher_host_delegate.cc
@@ -37,12 +37,13 @@ void SetOnlyAllowLoadFromCache(
   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) { }
@@ -58,7 +59,7 @@ class MaybeCancelResourceThrottle : public content::ResourceThrottle {
   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.
@@ -71,6 +72,25 @@ void MaybeCancelResourceThrottle::WillStartRequest(bool* defer) {
     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()) {
@@ -127,7 +147,7 @@ void AwResourceDispatcherHostDelegate::RequestBeginning(
     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) {