Bug 1620824 - Add content encoding support for TRRServiceChannel r=valentin

Differential Revision: https://phabricator.services.mozilla.com/D65898

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

modules/libpref/init/StaticPrefList.yaml

@@ -7384,6 +7384,12 @@
   value: false
   mirror: always
 
+# Whether to send an empty Accept-Encoding header for TRR requests
+- name: network.trr.send_empty_accept-encoding_headers
+  type: RelaxedAtomicBool
+  value: true
+  mirror: always
+
 # Whether to send the User-Agent header for TRR requests
 - name: network.trr.send_user-agent_headers
   type: RelaxedAtomicBool

netwerk/dns/TRR.cpp

@@ -395,6 +395,12 @@ nsresult TRR::SendHTTPRequest() {
     NS_ENSURE_SUCCESS(rv, rv);
   }
 
+  if (StaticPrefs::network_trr_send_empty_accept_encoding_headers()) {
+    rv = httpChannel->SetEmptyRequestHeader(
+        NS_LITERAL_CSTRING("Accept-Encoding"));
+    NS_ENSURE_SUCCESS(rv, rv);
+  }
+
   // set the *default* response content type
   if (NS_FAILED(httpChannel->SetContentType(
           NS_LITERAL_CSTRING("application/dns-message")))) {

netwerk/protocol/http/TRRServiceChannel.cpp

@@ -786,9 +786,71 @@ nsresult TRRServiceChannel::CallOnStartRequest() {
     mOnStartRequestCalled = true;
   }
 
+  if (!mResponseHead) {
+    return NS_OK;
+  }
+
+  nsAutoCString contentEncoding;
+  rv = mResponseHead->GetHeader(nsHttp::Content_Encoding, contentEncoding);
+  if (NS_FAILED(rv) || contentEncoding.IsEmpty()) {
+    return NS_OK;
+  }
+
+  Suspend();
+
+  RefPtr<TRRServiceChannel> self = this;
+  rv = NS_DispatchToMainThread(
+      NS_NewRunnableFunction("TRRServiceChannel::DoApplyContentConversions",
+                             [self]() {
+                               nsCOMPtr<nsIStreamListener> listener;
+                               nsresult rv = self->DoApplyContentConversions(
+                                   self->mListener, getter_AddRefs(listener),
+                                   nullptr);
+                               self->AfterApplyContentConversions(rv, listener);
+                             }),
+      NS_DISPATCH_NORMAL);
+  if (NS_FAILED(rv)) {
+    Resume();
+    return rv;
+  }
+
   return NS_OK;
 }
 
+void TRRServiceChannel::AfterApplyContentConversions(
+    nsresult aResult, nsIStreamListener* aListener) {
+  LOG(("TRRServiceChannel::AfterApplyContentConversions [this=%p]", this));
+  if (!mCurrentEventTarget->IsOnCurrentThread()) {
+    RefPtr<TRRServiceChannel> self = this;
+    nsCOMPtr<nsIStreamListener> listener = aListener;
+    self->mCurrentEventTarget->Dispatch(
+        NS_NewRunnableFunction(
+            "TRRServiceChannel::AfterApplyContentConversions",
+            [self, aResult, listener]() {
+              self->AfterApplyContentConversions(aResult, listener);
+            }),
+        NS_DISPATCH_NORMAL);
+    return;
+  }
+
+  Resume();
+
+  if (mCanceled) {
+    return;
+  }
+
+  if (NS_FAILED(aResult)) {
+    Unused << AsyncAbort(aResult);
+    return;
+  }
+
+  if (aListener) {
+    mListener = aListener;
+    mCompressListener = aListener;
+    mHasAppliedConversion = true;
+  }
+}
+
 void TRRServiceChannel::ProcessAltService() {
   // e.g. Alt-Svc: h2=":443"; ma=60
   // e.g. Alt-Svc: h2="otherhost:443"

netwerk/protocol/http/TRRServiceChannel.h

@@ -123,6 +123,8 @@ class TRRServiceChannel : public HttpBaseChannel,
   void DoNotifyListener();
   nsresult MaybeResolveProxyAndBeginConnect();
   nsresult ResolveProxy();
+  void AfterApplyContentConversions(nsresult aResult,
+                                    nsIStreamListener* aListener);
 
   // True only when we have computed the value of the top window origin.
   bool mTopWindowOriginComputed;