Bug 1729477 - Tweak SubresourceCacheValidationInfo to account for chrome uris. r=tnikkel

Turns out my patch above causes some failures because chrome:// channels
don't have cache information, so we conservatively assume they always
expire, which causes some interesting timing issues in a single test.
Fun stuff.

Tweak the code so that SubresourceCacheValidationInfo has the
pre-existing data:// URI special-case and also special-cases chrome://
URIs.

Differential Revision: https://phabricator.services.mozilla.com/D124921

dom/base/nsContentUtils.cpp

@@ -10494,7 +10494,8 @@ ScreenIntMargin nsContentUtils::GetWindowSafeAreaInsets(
 
 /* static */
 nsContentUtils::SubresourceCacheValidationInfo
-nsContentUtils::GetSubresourceCacheValidationInfo(nsIRequest* aRequest) {
+nsContentUtils::GetSubresourceCacheValidationInfo(nsIRequest* aRequest,
+                                                  nsIURI* aURI) {
   SubresourceCacheValidationInfo info;
   if (nsCOMPtr<nsICacheInfoChannel> cache = do_QueryInterface(aRequest)) {
     uint32_t value = 0;
@@ -10513,6 +10514,18 @@ nsContentUtils::GetSubresourceCacheValidationInfo(nsIRequest* aRequest) {
     }
   }
 
+  // data: URIs are safe to cache across documents under any circumstance, so we
+  // special-case them here even though the channel itself doesn't have any
+  // caching policy. Same for chrome:// uris.
+  //
+  // TODO(emilio): Figure out which other schemes that don't have caching
+  // policies are safe to cache. Blobs should be...
+  if (aURI && (aURI->SchemeIs("data") || dom::IsChromeURI(aURI))) {
+    MOZ_ASSERT(!info.mExpirationTime);
+    MOZ_ASSERT(!info.mMustRevalidate);
+    info.mExpirationTime = Some(0);  // 0 means "doesn't expire".
+  }
+
   return info;
 }
 

dom/base/nsContentUtils.h

@@ -3271,7 +3271,7 @@ class nsContentUtils {
    * stylesheets.
    */
   static SubresourceCacheValidationInfo GetSubresourceCacheValidationInfo(
-      nsIRequest*);
+      nsIRequest*, nsIURI*);
 
   static uint32_t SecondsFromPRTime(PRTime aTime) {
     return uint32_t(int64_t(aTime) / int64_t(PR_USEC_PER_SEC));

image/imgLoader.cpp

@@ -1880,10 +1880,10 @@ bool imgLoader::ValidateEntry(
   LOG_SCOPE(gImgLog, "imgLoader::ValidateEntry");
 
   // If the expiration time is zero, then the request has not gotten far enough
-  // to know when it will expire.
+  // to know when it will expire, or we know it will never expire (see
+  // nsContentUtils::GetSubresourceCacheValidationInfo).
   uint32_t expiryTime = aEntry->GetExpiryTime();
-  bool hasExpired =
-      expiryTime != 0 && expiryTime <= SecondsFromPRTime(PR_Now());
+  bool hasExpired = expiryTime && expiryTime <= SecondsFromPRTime(PR_Now());
 
   nsresult rv;
 

image/imgLoader.h

@@ -83,8 +83,8 @@ class imgCacheEntry {
 
   void UpdateLoadTime();
 
-  int32_t GetExpiryTime() const { return mExpiryTime; }
-  void SetExpiryTime(int32_t aExpiryTime) {
+  uint32_t GetExpiryTime() const { return mExpiryTime; }
+  void SetExpiryTime(uint32_t aExpiryTime) {
     mExpiryTime = aExpiryTime;
     Touch();
   }
@@ -130,7 +130,7 @@ class imgCacheEntry {
   uint32_t mDataSize;
   int32_t mTouchedTime;
   uint32_t mLoadTime;
-  int32_t mExpiryTime;
+  uint32_t mExpiryTime;
   nsExpirationState mExpirationState;
   bool mMustValidate : 1;
   bool mEvicted : 1;

image/imgRequest.cpp

@@ -544,7 +544,17 @@ void imgRequest::SetCacheValidation(imgCacheEntry* aCacheEntry,
     return;
   }
 
-  auto info = nsContentUtils::GetSubresourceCacheValidationInfo(aRequest);
+  RefPtr<imgRequest> req = aCacheEntry->GetRequest();
+  MOZ_ASSERT(req);
+  RefPtr<nsIURI> uri;
+  req->GetURI(getter_AddRefs(uri));
+  // TODO(emilio): Seems we should be able to assert `uri` is not null, but we
+  // get here in such cases sometimes (like for some redirects, see
+  // docshell/test/chrome/test_bug89419.xhtml).
+  //
+  // We have the original URI in the cache key though, probably we should be
+  // using that instead of relying on Init() getting called.
+  auto info = nsContentUtils::GetSubresourceCacheValidationInfo(aRequest, uri);
 
   // Expiration time defaults to 0. We set the expiration time on our entry if
   // it hasn't been set yet.

layout/style/StreamLoader.cpp

@@ -115,19 +115,8 @@ StreamLoader::OnStopRequest(nsIRequest* aRequest, nsresult aStatus) {
     }
   }  // run destructor for `bytes`
 
-  auto info = nsContentUtils::GetSubresourceCacheValidationInfo(aRequest);
-
-  // data: URIs are safe to cache across documents under any circumstance, so we
-  // special-case them here even though the channel itself doesn't have any
-  // caching policy.
-  //
-  // TODO(emilio): Figure out which other schemes that don't have caching
-  // policies are safe to cache. Blobs should be...
-  if (mSheetLoadData->mURI->SchemeIs("data")) {
-    MOZ_ASSERT(!info.mExpirationTime);
-    MOZ_ASSERT(!info.mMustRevalidate);
-    info.mExpirationTime = Some(0);  // 0 means "doesn't expire".
-  }
+  auto info = nsContentUtils::GetSubresourceCacheValidationInfo(
+      aRequest, mSheetLoadData->mURI);
 
   // For now, we never cache entries that we have to revalidate, or whose
   // channel don't support caching.