Bug 1482117 - Part 2: cache the result of IsThirdPartyChannel; r=mayhemer

cache the result to speed up

Differential Revision: https://phabricator.services.mozilla.com/D3423

--HG--
extra : moz-landing-system : lando

netwerk/protocol/http/nsHttpChannel.cpp

@@ -630,17 +630,8 @@ nsHttpChannel::Connect()
     LOG(("nsHttpChannel %p tracking resource=%d, cos=%u",
           this, isTrackingResource, mClassOfService));
 
-    if (isTrackingResource) {
-        nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
-          services::GetThirdPartyUtil();
-        bool result = false;
-        if (thirdPartyUtil &&
-            NS_SUCCEEDED(thirdPartyUtil->IsThirdPartyChannel(this, nullptr,
-                                                             &result)) &&
-            result) {
-
-            AddClassFlags(nsIClassOfService::Tail);
-        }
+    if (isTrackingResource && IsThirdPartyChannel()) {
+        AddClassFlags(nsIClassOfService::Tail);
     }
 
     if (WaitingForTailUnblock()) {
@@ -694,11 +685,7 @@ nsHttpChannel::CheckFastBlocked()
         Preferences::AddUintVarCache(&sFastBlockTimeout, "browser.fastblock.timeout");
     }
 
-    nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil = services::GetThirdPartyUtil();
-    bool result = false;
-    if (!thirdPartyUtil ||
-        NS_FAILED(thirdPartyUtil->IsThirdPartyChannel(this, nullptr, &result)) ||
-        !result) {
+    if (!IsThirdPartyChannel()) {
         return false;
     }
 
@@ -722,6 +709,29 @@ nsHttpChannel::CheckFastBlocked()
     return true;
 }
 
+bool
+nsHttpChannel::IsThirdPartyChannel()
+{
+    if (mIsThirdPartyChannel) {
+        return *mIsThirdPartyChannel;
+    }
+
+    nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil = services::GetThirdPartyUtil();
+    if (!thirdPartyUtil) {
+        return false;
+    }
+
+    bool isThirdPartyChannel;
+    if (NS_FAILED(thirdPartyUtil->IsThirdPartyChannel(this,
+                                                      nullptr,
+                                                      &isThirdPartyChannel))) {
+        return false;
+    }
+
+    mIsThirdPartyChannel.emplace(isThirdPartyChannel);
+    return *mIsThirdPartyChannel;
+}
+
 nsresult
 nsHttpChannel::ConnectOnTailUnblock()
 {
@@ -2325,13 +2335,8 @@ nsHttpChannel::ProcessResponse()
     // We consider top-level tracking resource as non-tracking if not in 3rd
     // party context.
     bool isThirdPartyAndTrackingResource = false;
-    if(mIsTrackingResource) {
-        nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
-          services::GetThirdPartyUtil();
-        if (thirdPartyUtil) {
-            thirdPartyUtil->IsThirdPartyChannel(this, nullptr,
-                                                &isThirdPartyAndTrackingResource);
-        }
+    if (mIsTrackingResource) {
+        isThirdPartyAndTrackingResource = IsThirdPartyChannel();
     }
 
     if (referrer) {

netwerk/protocol/http/nsHttpChannel.h

@@ -32,6 +32,7 @@
 #include "nsIRaceCacheWithNetwork.h"
 #include "mozilla/extensions/PStreamFilterParent.h"
 #include "mozilla/Mutex.h"
+#include "mozilla/Maybe.h"
 
 class nsDNSPrefetch;
 class nsICancelable;
@@ -660,6 +661,10 @@ private:
     // Check if current channel should be canceled by FastBlock rules.
     bool CheckFastBlocked();
 
+    // This caches the result of mozIThirdPartyUtil::IsThirdPartyChannel.
+    bool IsThirdPartyChannel();
+    Maybe<bool> mIsThirdPartyChannel;
+
     nsCString mUsername;
 
     // If non-null, warnings should be reported to this object.