Bug 1148544 - Figure out UA override once per LoadGroup and cache it, rather than once per channel. r=nwgh

netwerk/base/nsILoadGroup.idl

@@ -58,7 +58,7 @@ interface nsILoadGroup : nsIRequest
      * By the time this call ends, aRequest will have been removed from the
      * loadgroup, even if this function throws an exception.
      */
-    void removeRequest(in nsIRequest aRequest, 
+    void removeRequest(in nsIRequest aRequest,
                        in nsISupports aContext,
                        in nsresult aStatus);
 
@@ -97,4 +97,10 @@ interface nsILoadGroup : nsIRequest
      * the docShell has created the default request.)
      */
     attribute nsLoadFlags defaultLoadFlags;
+
+    /**
+     * The cached user agent override created by UserAgentOverrides.jsm. Used
+     * for all sub-resource requests in the loadgroup.
+     */
+    attribute ACString userAgentOverrideCache;
 };

netwerk/base/nsLoadGroup.cpp

@@ -172,7 +172,7 @@ nsLoadGroup::GetName(nsACString &result)
         result.Truncate();
         return NS_OK;
     }
-    
+
     return mDefaultLoadRequest->GetName(result);
 }
 
@@ -188,9 +188,9 @@ nsLoadGroup::GetStatus(nsresult *status)
 {
     if (NS_SUCCEEDED(mStatus) && mDefaultLoadRequest)
         return mDefaultLoadRequest->GetStatus(status);
-    
+
     *status = mStatus;
-    return NS_OK; 
+    return NS_OK;
 }
 
 static bool
@@ -480,7 +480,7 @@ nsLoadGroup::AddRequest(nsIRequest *request, nsISupports* ctxt)
         rv = MergeLoadFlags(request, flags);
     }
     if (NS_FAILED(rv)) return rv;
-    
+
     //
     // Add the request to the list of active requests...
     //
@@ -810,10 +810,24 @@ nsLoadGroup::SetDefaultLoadFlags(uint32_t aFlags)
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsLoadGroup::GetUserAgentOverrideCache(nsACString & aUserAgentOverrideCache)
+{
+  aUserAgentOverrideCache = mUserAgentOverrideCache;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsLoadGroup::SetUserAgentOverrideCache(const nsACString & aUserAgentOverrideCache)
+{
+  mUserAgentOverrideCache = aUserAgentOverrideCache;
+  return NS_OK;
+}
+
 
 ////////////////////////////////////////////////////////////////////////////////
 
-void 
+void
 nsLoadGroup::TelemetryReport()
 {
     if (mDefaultLoadIsTimed) {

netwerk/base/nsLoadGroup.h

@@ -29,7 +29,7 @@ class nsLoadGroup : public nsILoadGroup,
 {
 public:
     NS_DECL_AGGREGATED
-    
+
     ////////////////////////////////////////////////////////////////////////////
     // nsIRequest methods:
     NS_DECL_NSIREQUEST
@@ -79,7 +79,7 @@ protected:
 
     nsWeakPtr                       mObserver;
     nsWeakPtr                       mParentLoadGroup;
-    
+
     nsresult                        mStatus;
     int32_t                         mPriority;
     bool                            mIsCanceling;
@@ -92,6 +92,8 @@ protected:
 
     /* For nsPILoadGroupInternal */
     uint32_t                        mTimedNonCachedRequestsUntilOnEndPageLoad;
+
+    nsCString                       mUserAgentOverrideCache;
 };
 
 #endif // nsLoadGroup_h__

netwerk/protocol/http/HttpBaseChannel.cpp

@@ -2476,6 +2476,41 @@ HttpBaseChannel::ShouldIntercept(nsIURI* aURI)
   return shouldIntercept;
 }
 
+void
+HttpBaseChannel::SetLoadGroupUserAgentOverride()
+{
+  nsCOMPtr<nsIURI> uri;
+  GetURI(getter_AddRefs(uri));
+  nsAutoCString uriScheme;
+  if (uri) {
+    uri->GetScheme(uriScheme);
+  }
+  nsCOMPtr<nsILoadGroupChild> childLoadGroup = do_QueryInterface(mLoadGroup);
+  nsCOMPtr<nsILoadGroup> rootLoadGroup;
+  if (childLoadGroup) {
+    childLoadGroup->GetRootLoadGroup(getter_AddRefs(rootLoadGroup));
+  }
+  if (rootLoadGroup && !uriScheme.EqualsLiteral("file")) {
+    nsAutoCString ua;
+    if (nsContentUtils::IsNonSubresourceRequest(this)) {
+      gHttpHandler->OnUserAgentRequest(this);
+      GetRequestHeader(NS_LITERAL_CSTRING("User-Agent"), ua);
+      rootLoadGroup->SetUserAgentOverrideCache(ua);
+    } else {
+      GetRequestHeader(NS_LITERAL_CSTRING("User-Agent"), ua);
+      // Don't overwrite the UA if it is already set (eg by an XHR with explicit UA).
+      if (ua.IsEmpty()) {
+        rootLoadGroup->GetUserAgentOverrideCache(ua);
+        SetRequestHeader(NS_LITERAL_CSTRING("User-Agent"), ua, false);
+      }
+    }
+  } else {
+    // If the root loadgroup doesn't exist or if the channel's URI's scheme is "file",
+    // fall back on getting the UA override per channel.
+    gHttpHandler->OnUserAgentRequest(this);
+  }
+}
+
 //-----------------------------------------------------------------------------
 // nsHttpChannel::nsITraceableChannel
 //-----------------------------------------------------------------------------

netwerk/protocol/http/HttpBaseChannel.h

@@ -353,6 +353,8 @@ protected:
   // for a possible synthesized response instead.
   bool ShouldIntercept(nsIURI* aURI = nullptr);
 
+  void SetLoadGroupUserAgentOverride();
+
   friend class PrivateBrowsingChannel<HttpBaseChannel>;
   friend class InterceptFailedOnStop;
 

netwerk/protocol/http/HttpChannelChild.cpp

@@ -1805,9 +1805,12 @@ HttpChannelChild::AsyncOpen(nsIStreamListener *listener, nsISupports *aContext)
     return NS_OK;
   }
 
-  // Set user agent override
+  // Set user agent override from docshell
   HttpBaseChannel::SetDocshellUserAgentOverride();
 
+  // Set user agent override from loadgroup
+  HttpBaseChannel::SetLoadGroupUserAgentOverride();
+
   MOZ_ASSERT_IF(mPostRedirectChannelShouldUpgrade,
                 mPostRedirectChannelShouldIntercept);
   bool shouldUpgrade = mPostRedirectChannelShouldUpgrade;

netwerk/protocol/http/UserAgentOverrides.jsm

@@ -46,9 +46,9 @@ this.UserAgentOverrides = {
     Services.prefs.addObserver(PREF_OVERRIDES_ENABLED, buildOverrides, false);
 
     try {
-      Services.obs.addObserver(HTTP_on_modify_request, "http-on-modify-request", false);
+      Services.obs.addObserver(HTTP_on_useragent_request, "http-on-useragent-request", false);
     } catch (x) {
-      // The http-on-modify-request notification is disallowed in content processes.
+      // The http-on-useragent-request notification is disallowed in content processes.
     }
 
     UserAgentUpdates.init(function(overrides) {
@@ -118,7 +118,7 @@ this.UserAgentOverrides = {
 
     Services.prefs.removeObserver(PREF_OVERRIDES_ENABLED, buildOverrides);
 
-    Services.obs.removeObserver(HTTP_on_modify_request, "http-on-modify-request");
+    Services.obs.removeObserver(HTTP_on_useragent_request, "http-on-useragent-request");
   },
 
   receiveMessage: function(aMessage) {
@@ -169,7 +169,7 @@ function buildOverrides() {
   }
 }
 
-function HTTP_on_modify_request(aSubject, aTopic, aData) {
+function HTTP_on_useragent_request(aSubject, aTopic, aData) {
   let channel = aSubject.QueryInterface(Ci.nsIHttpChannel);
 
   for (let callback of gOverrideFunctions) {

netwerk/protocol/http/nsHttpChannel.cpp

@@ -5228,6 +5228,11 @@ nsHttpChannel::BeginConnect()
     // notify "http-on-modify-request" observers
     CallOnModifyRequestObservers();
 
+    // If mLoadGroup is null, e10s is enabled and this will be handled by HttpChannelChild.
+    if (mLoadGroup) {
+      HttpBaseChannel::SetLoadGroupUserAgentOverride();
+    }
+
     // Check to see if we should redirect this channel elsewhere by
     // nsIHttpChannel.redirectTo API request
     if (mAPIRedirectToURI) {

netwerk/protocol/http/nsHttpHandler.h

@@ -275,6 +275,12 @@ public:
         NotifyObservers(chan, NS_HTTP_ON_MODIFY_REQUEST_TOPIC);
     }
 
+    // Called by the channel and cached in the loadGroup
+    void OnUserAgentRequest(nsIHttpChannel *chan)
+    {
+      NotifyObservers(chan, NS_HTTP_ON_USERAGENT_REQUEST_TOPIC);
+    }
+
     // Called by the channel once headers are available
     void OnExamineResponse(nsIHttpChannel *chan)
     {

netwerk/protocol/http/nsIHttpProtocolHandler.idl

@@ -113,5 +113,14 @@ interface nsIHttpProtocolHandler : nsIProxiedProtocolHandler
  */
 #define NS_HTTP_ON_EXAMINE_CACHED_RESPONSE_TOPIC "http-on-examine-cached-response"
 
+/**
+ * Before an HTTP request corresponding to a channel with the LOAD_DOCUMENT_URI
+ * flag is sent to the server, this observer topic is notified. The observer of
+ * this topic can then choose to modify the user agent for this request before
+ * the request is actually sent to the server. Additionally, the modified user
+ * agent will be propagated to sub-resource requests from the same load group.
+ */
+#define NS_HTTP_ON_USERAGENT_REQUEST_TOPIC "http-on-useragent-request"
+
 
 %}