diff --git a/include/binder/PermissionCache.h b/include/binder/PermissionCache.h
new file mode 100644
index 0000000..1171d48
--- /dev/null
+++ b/include/binder/PermissionCache.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2009 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef BINDER_PERMISSION_H
+#define BINDER_PERMISSION_H
+
+#include <stdint.h>
+#include <unistd.h>
+
+#include <utils/String16.h>
+#include <utils/Singleton.h>
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+/*
+ * PermissionCache caches permission checks for a given uid.
+ *
+ * Currently the cache is not updated when there is a permission change,
+ * for instance when an application is uninstalled.
+ *
+ * IMPORTANT: for the reason stated above, only system permissions are safe
+ * to cache. This restriction may be lifted at a later time.
+ *
+ */
+
+class PermissionCache : Singleton<PermissionCache> {
+    struct Entry {
+        String16    name;
+        uid_t       uid;
+        bool        granted;
+        inline bool operator < (const Entry& e) const {
+            return (uid == e.uid) ? (name < e.name) : (uid < e.uid);
+        }
+    };
+    mutable Mutex mLock;
+    // we pool all the permission names we see, as many permissions checks
+    // will have identical names
+    SortedVector< String16 > mPermissionNamesPool;
+    // this is our cache per say. it stores pooled names.
+    SortedVector< Entry > mCache;
+
+    // free the whole cache, but keep the permission name pool
+    void purge();
+
+    status_t check(bool* granted,
+            const String16& permission, uid_t uid) const;
+
+    void cache(const String16& permission, uid_t uid, bool granted);
+
+public:
+    PermissionCache();
+
+    static bool checkCallingPermission(const String16& permission);
+
+    static bool checkCallingPermission(const String16& permission,
+                                int32_t* outPid, int32_t* outUid);
+
+    static bool checkPermission(const String16& permission,
+            pid_t pid, uid_t uid);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif /* BINDER_PERMISSION_H */