1 files changed, 68 insertions, 0 deletions
diff --git a/accessible/windows/msaa/MsaaIdGenerator.h b/accessible/windows/msaa/MsaaIdGenerator.h
new file mode 100644
index 0000000000..d1f2c4974e
--- /dev/null
+++ b/accessible/windows/msaa/MsaaIdGenerator.h
@@ -0,0 +1,68 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_MsaaIdGenerator_h
+#define mozilla_a11y_MsaaIdGenerator_h
+
+#include "mozilla/a11y/IDSet.h"
+
+#include "mozilla/dom/ipc/IdType.h"
+#include "mozilla/NotNull.h"
+#include "mozilla/UniquePtr.h"
+#include "nsITimer.h"
+
+namespace mozilla {
+namespace a11y {
+
+class MsaaAccessible;
+class sdnAccessible;
+
+/**
+ * This class is responsible for generating child IDs used by our MSAA
+ * implementation.
+ *
+ * If the accessibility cache is disabled, we must differentiate IDs based on
+ * the originating process of the accessible, so a portion of the ID's bits are
+ * allocated to storing that information. The remaining bits represent the
+ * unique ID of the accessible, within that content process.
+ *
+ * The constants kNumContentProcessIDBits and kNumUniqueIDBits in the
+ * implementation are responsible for determining the proportion of bits that
+ * are allocated for each purpose.
+ *
+ * If the accessibility cache is enabled, we don't need to differentiate IDs
+ * based on the originating process, so all bits of the ID are used for the
+ * unique ID.
+ */
+class MsaaIdGenerator {
+ public:
+  uint32_t GetID();
+  void ReleaseID(NotNull<MsaaAccessible*> aMsaaAcc);
+  void ReleaseID(NotNull<sdnAccessible*> aSdnAcc);
+  bool IsChromeID(uint32_t aID);
+  bool IsIDForThisContentProcess(uint32_t aID);
+  bool IsIDForContentProcess(uint32_t aID,
+                             dom::ContentParentId aIPCContentProcessId);
+  bool IsSameContentProcessFor(uint32_t aFirstID, uint32_t aSecondID);
+
+  uint32_t GetContentProcessIDFor(dom::ContentParentId aIPCContentProcessID);
+  void ReleaseContentProcessIDFor(dom::ContentParentId aIPCContentProcessID);
+
+ private:
+  bool ReleaseID(uint32_t aID);
+  uint32_t ResolveContentProcessID();
+  void ReleasePendingIDs();
+
+ private:
+  UniquePtr<IDSet> mIDSet;
+  nsTArray<uint32_t> mIDsToRelease;
+  nsCOMPtr<nsITimer> mReleaseIDTimer;
+};
+
+}  // namespace a11y
+}  // namespace mozilla
+
+#endif  // mozilla_a11y_MsaaIdGenerator_h