From b5dcdc80bb9a9bad9e989ac9f9818c50cf5d7ff6 Mon Sep 17 00:00:00 2001
From: Valentin Gosu <valentin.gosu@gmail.com>
Date: Mon, 19 Oct 2020 07:45:46 +0000
Subject: [PATCH] Bug 1669780 - Backed out changeset 29d1be2b96f9 (Bug 1569715)
 for causing us to skip CORS preflight cache for POST requests
 r=necko-reviewers,kershaw

Differential Revision: https://phabricator.services.mozilla.com/D93746
---
 netwerk/protocol/http/nsCORSListenerProxy.cpp | 29 +++++--------------
 1 file changed, 8 insertions(+), 21 deletions(-)

diff --git a/netwerk/protocol/http/nsCORSListenerProxy.cpp b/netwerk/protocol/http/nsCORSListenerProxy.cpp
index 218f494360d2..14a03920a297 100644
--- a/netwerk/protocol/http/nsCORSListenerProxy.cpp
+++ b/netwerk/protocol/http/nsCORSListenerProxy.cpp
@@ -1399,27 +1399,10 @@ nsresult nsCORSListenerProxy::StartCORSPreflight(
   bool withCredentials =
       originalLoadInfo->GetCookiePolicy() == nsILoadInfo::SEC_COOKIES_INCLUDE;
 
-  nsPreflightCache::CacheEntry* entry = nullptr;
-
-  nsLoadFlags loadFlags;
-  rv = httpChannel->GetLoadFlags(&loadFlags);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  if (sPreflightCache) {
-    nsCOMPtr<nsICacheInfoChannel> cacheInfoChannel =
-        do_QueryInterface(httpChannel);
-    bool preferCacheLoadOverBypass = false;
-    rv = cacheInfoChannel->GetPreferCacheLoadOverBypass(
-        &preferCacheLoadOverBypass);
-    NS_ENSURE_SUCCESS(rv, rv);
-
-    if (!(loadFlags & (nsIRequest::LOAD_BYPASS_CACHE |
-                       nsICachingChannel::LOAD_BYPASS_LOCAL_CACHE)) ||
-        ((loadFlags & nsIRequest::LOAD_FROM_CACHE) &&
-         preferCacheLoadOverBypass)) {
-      entry = sPreflightCache->GetEntry(uri, principal, withCredentials, false);
-    }
-  }
+  nsPreflightCache::CacheEntry* entry =
+      sPreflightCache
+          ? sPreflightCache->GetEntry(uri, principal, withCredentials, false)
+          : nullptr;
 
   if (entry && entry->CheckRequest(method, aUnsafeHeaders)) {
     aCallback->OnPreflightSucceeded();
@@ -1447,6 +1430,10 @@ nsresult nsCORSListenerProxy::StartCORSPreflight(
   NS_ENSURE_SUCCESS(rv, rv);
   nsCOMPtr<nsILoadContext> loadContext = do_GetInterface(callbacks);
 
+  nsLoadFlags loadFlags;
+  rv = aRequestChannel->GetLoadFlags(&loadFlags);
+  NS_ENSURE_SUCCESS(rv, rv);
+
   // Preflight requests should never be intercepted by service workers and
   // are always anonymous.
   // NOTE: We ignore CORS checks on synthesized responses (see the CORS