Bug 1437080 P3 Make SetFetchCacheMode() to clear other cache flags an…

…d assert the final value. r=valentin

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -2765,6 +2765,25 @@ HttpBaseChannel::GetFetchCacheMode(uint32_t* aFetchCacheMode)
   return NS_OK;
 }
 
+namespace {
+
+void
+SetCacheFlags(uint32_t& aLoadFlags, uint32_t aFlags)
+{
+  // First, clear any possible cache related flags.
+  uint32_t allPossibleFlags = nsIRequest::INHIBIT_CACHING
+                            | nsIRequest::LOAD_BYPASS_CACHE
+                            | nsIRequest::VALIDATE_ALWAYS
+                            | nsIRequest::LOAD_FROM_CACHE
+                            | nsICachingChannel::LOAD_ONLY_FROM_CACHE;
+  aLoadFlags &= ~allPossibleFlags;
+
+  // Then set the new flags.
+  aLoadFlags |= aFlags;
+}
+
+} // anonymous namespace
+
 NS_IMETHODIMP
 HttpBaseChannel::SetFetchCacheMode(uint32_t aFetchCacheMode)
 {
@@ -2779,20 +2798,20 @@ HttpBaseChannel::SetFetchCacheMode(uint32_t aFetchCacheMode)
   case nsIHttpChannelInternal::FETCH_CACHE_MODE_NO_STORE:
     // no-store means don't consult the cache on the way to the network, and
     // don't store the response in the cache even if it's cacheable.
-    mLoadFlags |= INHIBIT_CACHING | LOAD_BYPASS_CACHE;
+    SetCacheFlags(mLoadFlags, INHIBIT_CACHING | LOAD_BYPASS_CACHE);
     break;
   case nsIHttpChannelInternal::FETCH_CACHE_MODE_RELOAD:
     // reload means don't consult the cache on the way to the network, but
     // do store the response in the cache if possible.
-    mLoadFlags |= LOAD_BYPASS_CACHE;
+    SetCacheFlags(mLoadFlags, LOAD_BYPASS_CACHE);
     break;
   case nsIHttpChannelInternal::FETCH_CACHE_MODE_NO_CACHE:
     // no-cache means always validate what's in the cache.
-    mLoadFlags |= VALIDATE_ALWAYS;
+    SetCacheFlags(mLoadFlags, VALIDATE_ALWAYS);
     break;
   case nsIHttpChannelInternal::FETCH_CACHE_MODE_FORCE_CACHE:
     // force-cache means don't validate unless if the response would vary.
-    mLoadFlags |= VALIDATE_NEVER;
+    SetCacheFlags(mLoadFlags, LOAD_FROM_CACHE);
     break;
   case nsIHttpChannelInternal::FETCH_CACHE_MODE_ONLY_IF_CACHED:
     // only-if-cached means only from cache, no network, no validation, generate
@@ -2801,10 +2820,17 @@ HttpBaseChannel::SetFetchCacheMode(uint32_t aFetchCacheMode)
     // the user has things in their cache without any network traffic side
     // effects) are addressed in the Request constructor which enforces/requires
     // same-origin request mode.
-    mLoadFlags |= VALIDATE_NEVER | nsICachingChannel::LOAD_ONLY_FROM_CACHE;
+    SetCacheFlags(mLoadFlags, LOAD_FROM_CACHE |
+                              nsICachingChannel::LOAD_ONLY_FROM_CACHE);
     break;
   }
 
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+  uint32_t finalMode = 0;
+  MOZ_ALWAYS_SUCCEEDS(GetFetchCacheMode(&finalMode));
+  MOZ_DIAGNOSTIC_ASSERT(finalMode == aFetchCacheMode);
+#endif // MOZ_DIAGNOSTIC_ASSERT_ENABLED
+
   return NS_OK;
 }