Bug 1523638 - Part 4: Move NextWindowId logic into nsContentUtils, r=kmag

Differential Revision: https://phabricator.services.mozilla.com/D37651

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

docshell/base/nsDocShell.cpp

@@ -309,7 +309,7 @@ static void DecreasePrivateDocShellCount() {
 
 nsDocShell::nsDocShell(BrowsingContext* aBrowsingContext)
     : nsDocLoader(),
-      mContentWindowID(NextWindowID()),
+      mContentWindowID(nsContentUtils::GenerateWindowId()),
       mBrowsingContext(aBrowsingContext),
       mForcedCharset(nullptr),
       mParentCharset(nullptr),

dom/base/nsContentUtils.cpp

@@ -9848,8 +9848,12 @@ bool nsContentUtils::IsLocalRefURL(const nsString& aString) {
   return !aString.IsEmpty() && aString[0] == '#';
 }
 
-static const uint64_t kIdProcessBits = 32;
-static const uint64_t kIdBits = 64 - kIdProcessBits;
+// We use only 53 bits for the ID so that it can be converted to and from a JS
+// value without loss of precision. The upper bits of the ID hold the process
+// ID. The lower bits identify the object itself.
+static constexpr uint64_t kIdTotalBits = 53;
+static constexpr uint64_t kIdProcessBits = 22;
+static constexpr uint64_t kIdBits = kIdTotalBits - kIdProcessBits;
 
 /* static */ uint64_t GenerateProcessSpecificId(uint64_t aId) {
   uint64_t processId = 0;
@@ -9874,7 +9878,7 @@ static const uint64_t kIdBits = 64 - kIdProcessBits;
   return (processBits << kIdBits) | bits;
 }
 
-// Tab ID is composed in a similar manner of Window ID.
+// Next process-local Tab ID.
 static uint64_t gNextTabId = 0;
 
 /* static */
@@ -9882,7 +9886,7 @@ uint64_t nsContentUtils::GenerateTabId() {
   return GenerateProcessSpecificId(++gNextTabId);
 }
 
-// Browsing context ID is composed in a similar manner of Window ID.
+// Next process-local Browsing Context ID.
 static uint64_t gNextBrowsingContextId = 0;
 
 /* static */
@@ -9890,6 +9894,14 @@ uint64_t nsContentUtils::GenerateBrowsingContextId() {
   return GenerateProcessSpecificId(++gNextBrowsingContextId);
 }
 
+// Next process-local Window ID.
+static uint64_t gNextWindowId = 0;
+
+/* static */
+uint64_t nsContentUtils::GenerateWindowId() {
+  return GenerateProcessSpecificId(++gNextWindowId);
+}
+
 /* static */
 bool nsContentUtils::GetUserIsInteracting() {
   return UserInteractionObserver::sUserActive;

dom/base/nsContentUtils.h

@@ -3075,6 +3075,12 @@ class nsContentUtils {
    */
   static uint64_t GenerateBrowsingContextId();
 
+  /**
+   * Generate a window ID which is unique across processes and will never be
+   * recycled.
+   */
+  static uint64_t GenerateWindowId();
+
   /**
    * Determine whether or not the user is currently interacting with the web
    * browser. This method is safe to call from off of the main thread.

dom/base/nsGlobalWindowInner.cpp

@@ -7199,13 +7199,6 @@ bool nsPIDOMWindowInner::HasStorageAccessGranted(
   return mStorageAccessGranted.Contains(aPermissionKey);
 }
 
-// XXX: Can we define this in a header instead of here?
-namespace mozilla {
-namespace dom {
-extern uint64_t NextWindowID();
-}  // namespace dom
-}  // namespace mozilla
-
 nsPIDOMWindowInner::nsPIDOMWindowInner(nsPIDOMWindowOuter* aOuterWindow)
     : mMutationBits(0),
       mActivePeerConnections(0),
@@ -7218,8 +7211,7 @@ nsPIDOMWindowInner::nsPIDOMWindowInner(nsPIDOMWindowOuter* aOuterWindow)
       mMayHavePointerEnterLeaveEventListener(false),
       mMayHaveTextEventListenerInDefaultGroup(false),
       mOuterWindow(aOuterWindow),
-      // Make sure no actual window ends up with mWindowID == 0
-      mWindowID(NextWindowID()),
+      mWindowID(nsContentUtils::GenerateWindowId()),
       mHasNotifiedGlobalCreated(false),
       mMarkedCCGeneration(0),
       mHasTriedToCacheTopInnerWindow(false),

dom/ipc/ContentChild.cpp

@@ -3213,48 +3213,6 @@ mozilla::ipc::IPCResult ContentChild::RecvSetAudioSessionData(
 #endif
 }
 
-// This code goes here rather than nsGlobalWindow.cpp because nsGlobalWindow.cpp
-// can't include ContentChild.h since it includes windows.h.
-
-static uint64_t gNextWindowID = 0;
-
-// We use only 53 bits for the window ID so that it can be converted to and from
-// a JS value without loss of precision. The upper bits of the window ID hold
-// the process ID. The lower bits identify the window.
-static const uint64_t kWindowIDTotalBits = 53;
-static const uint64_t kWindowIDProcessBits = 22;
-static const uint64_t kWindowIDWindowBits =
-    kWindowIDTotalBits - kWindowIDProcessBits;
-
-// Try to return a window ID that is unique across processes and that will never
-// be recycled.
-uint64_t NextWindowID() {
-  uint64_t processID = 0;
-  if (XRE_IsContentProcess()) {
-    ContentChild* cc = ContentChild::GetSingleton();
-    processID = cc->GetID();
-  }
-
-  MOZ_RELEASE_ASSERT(processID < (uint64_t(1) << kWindowIDProcessBits));
-  uint64_t processBits =
-      processID & ((uint64_t(1) << kWindowIDProcessBits) - 1);
-
-  // Make sure no actual window ends up with mWindowID == 0.
-  uint64_t windowID = ++gNextWindowID;
-
-  MOZ_RELEASE_ASSERT(windowID < (uint64_t(1) << kWindowIDWindowBits));
-  uint64_t windowBits = windowID & ((uint64_t(1) << kWindowIDWindowBits) - 1);
-
-  // Make sure that the middleman process doesn't generate WindowIDs which
-  // conflict with the process it's wrapping (which shares a ContentParentID
-  // with it).
-  if (recordreplay::IsMiddleman()) {
-    windowBits |= uint64_t(1) << (kWindowIDWindowBits - 1);
-  }
-
-  return (processBits << kWindowIDWindowBits) | windowBits;
-}
-
 mozilla::ipc::IPCResult ContentChild::RecvInvokeDragSession(
     nsTArray<IPCDataTransfer>&& aTransfers, const uint32_t& aAction) {
   nsCOMPtr<nsIDragService> dragService =

dom/ipc/ContentChild.h

@@ -835,8 +835,6 @@ class ContentChild final : public PContentChild,
   DISALLOW_EVIL_CONSTRUCTORS(ContentChild);
 };
 
-uint64_t NextWindowID();
-
 }  // namespace dom
 }  // namespace mozilla