Bug 1731792 - Part 2: Respect AppType in ImageCacheKey, r=emilio

This attribute is not used in Gecko, but exists for use by other
applications. Specifically, the APP_TYPE_EDITOR type is given permission
to load privileged images as tested by browser_docshell_type_editor.js.
Before these changes, that test passed because the docshell was loaded
in a different process, so the cache was empty when each load occurred,
but after my changes the process ends up being re-used, so the image
cache bypasses this check.

This changes the image cache key to also include the app type
information so that it will be compared before re-using the entry.

Depends on D126405

Differential Revision: https://phabricator.services.mozilla.com/D126557

image/ImageCacheKey.cpp

@@ -35,7 +35,8 @@ ImageCacheKey::ImageCacheKey(nsIURI* aURI, const OriginAttributes& aAttrs,
       mOriginAttributes(aAttrs),
       mControlledDocument(GetSpecialCaseDocumentToken(aDocument)),
       mIsolationKey(GetIsolationKey(aDocument, aURI)),
-      mIsChrome(false) {
+      mIsChrome(false),
+      mAppType(GetAppType(aDocument)) {
   if (mURI->SchemeIs("chrome")) {
     mIsChrome = true;
   }
@@ -47,7 +48,8 @@ ImageCacheKey::ImageCacheKey(const ImageCacheKey& aOther)
       mControlledDocument(aOther.mControlledDocument),
       mIsolationKey(aOther.mIsolationKey),
       mHash(aOther.mHash),
-      mIsChrome(aOther.mIsChrome) {}
+      mIsChrome(aOther.mIsChrome),
+      mAppType(aOther.mAppType) {}
 
 ImageCacheKey::ImageCacheKey(ImageCacheKey&& aOther)
     : mURI(std::move(aOther.mURI)),
@@ -55,7 +57,8 @@ ImageCacheKey::ImageCacheKey(ImageCacheKey&& aOther)
       mControlledDocument(aOther.mControlledDocument),
       mIsolationKey(aOther.mIsolationKey),
       mHash(aOther.mHash),
-      mIsChrome(aOther.mIsChrome) {}
+      mIsChrome(aOther.mIsChrome),
+      mAppType(aOther.mAppType) {}
 
 bool ImageCacheKey::operator==(const ImageCacheKey& aOther) const {
   // Don't share the image cache between a controlled document and anything
@@ -73,6 +76,10 @@ bool ImageCacheKey::operator==(const ImageCacheKey& aOther) const {
   if (mOriginAttributes != aOther.mOriginAttributes) {
     return false;
   }
+  // Don't share the image cache between two different appTypes
+  if (mAppType != aOther.mAppType) {
+    return false;
+  }
 
   // For non-blob URIs, compare the URIs.
   bool equals = false;
@@ -96,7 +103,7 @@ void ImageCacheKey::EnsureHash() const {
   hash = HashString(spec);
 
   hash = AddToHash(hash, HashString(suffix), HashString(mIsolationKey),
-                   HashString(ptr));
+                   HashString(ptr), mAppType);
   mHash.emplace(hash);
 }
 
@@ -165,5 +172,24 @@ nsCString ImageCacheKey::GetIsolationKey(Document* aDocument, nsIURI* aURI) {
   return ""_ns;
 }
 
+/* static */
+nsIDocShell::AppType ImageCacheKey::GetAppType(Document* aDocument) {
+  if (!aDocument) {
+    return nsIDocShell::APP_TYPE_UNKNOWN;
+  }
+
+  nsCOMPtr<nsIDocShellTreeItem> dsti = aDocument->GetDocShell();
+  if (!dsti) {
+    return nsIDocShell::APP_TYPE_UNKNOWN;
+  }
+
+  nsCOMPtr<nsIDocShellTreeItem> root;
+  dsti->GetInProcessRootTreeItem(getter_AddRefs(root));
+  if (nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(root)) {
+    return docShell->GetAppType();
+  }
+  return nsIDocShell::APP_TYPE_UNKNOWN;
+}
+
 }  // namespace image
 }  // namespace mozilla

image/ImageCacheKey.h

@@ -14,6 +14,7 @@
 #include "mozilla/Maybe.h"
 #include "mozilla/RefPtr.h"
 #include "PLDHashTable.h"
+#include "nsIDocShell.h"
 
 class nsIURI;
 
@@ -70,6 +71,10 @@ class ImageCacheKey final {
   // document's base domain. This is handled by this method.
   static nsCString GetIsolationKey(dom::Document* aDocument, nsIURI* aURI);
 
+  // The AppType of the docshell an image is loaded in can influence whether the
+  // image is allowed to load. The specific AppType is fetched by this method.
+  static nsIDocShell::AppType GetAppType(dom::Document* aDocument);
+
   void EnsureHash() const;
 
   nsCOMPtr<nsIURI> mURI;
@@ -78,6 +83,7 @@ class ImageCacheKey final {
   nsCString mIsolationKey;
   mutable Maybe<PLDHashNumber> mHash;
   bool mIsChrome;
+  nsIDocShell::AppType mAppType;
 };
 
 }  // namespace image