Discourage use of "_data" column.

Moving forward, all client file access really needs to be going
through explicit APIs like openFileDescriptor(), since that allows
the provider to better protect its underlying files.

This change also changes several classes to use the AutoClosable
pattern, which enables try-with-resources usage.  Older release()
methods are deprecated in favor of close().

Uniformly apply CloseGuard across several classes, using
AtomicBoolean to avoid double-freeing, and fix several resource
leaks and bugs related to MediaScanner allocation.  Switch
MediaScanner and friends to use public API instead of raw AIDL calls.

Bug: 22958127
Change-Id: Id722379f72c9e4b80d8b72550d7ce90e5e2bc786

1 files changed, 36 insertions, 29 deletions

diff --git a/drm/java/android/drm/DrmManagerClient.java b/drm/java/android/drm/DrmManagerClient.java
index c05ea2e1a1e5..704f0ce7624b 100644
--- a/drm/java/android/drm/DrmManagerClient.java
+++ b/drm/java/android/drm/DrmManagerClient.java
@@ -38,13 +38,14 @@ import java.io.IOException;
 import java.lang.ref.WeakReference;
 import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * The main programming interface for the DRM framework. An application must instantiate this class
  * to access DRM agents through the DRM framework.
  *
  */
-public class DrmManagerClient {
+public class DrmManagerClient implements AutoCloseable {
     /**
      * Indicates that a request was successful or that no error occurred.
      */
@@ -61,6 +62,7 @@ public class DrmManagerClient {
     HandlerThread mEventThread;
     private static final String TAG = "DrmManagerClient";
 
+    private final AtomicBoolean mClosed = new AtomicBoolean();
     private final CloseGuard mCloseGuard = CloseGuard.get();
 
     static {
@@ -117,7 +119,6 @@ public class DrmManagerClient {
 
     private int mUniqueId;
     private long mNativeContext;
-    private volatile boolean mReleased;
     private Context mContext;
     private InfoHandler mInfoHandler;
     private EventHandler mEventHandler;
@@ -261,41 +262,47 @@ public class DrmManagerClient {
     @Override
     protected void finalize() throws Throwable {
         try {
-            if (mCloseGuard != null) {
-                mCloseGuard.warnIfOpen();
-            }
-            release();
+            mCloseGuard.warnIfOpen();
+            close();
         } finally {
             super.finalize();
         }
     }
 
     /**
-     * Releases resources associated with the current session of DrmManagerClient.
-     *
-     * It is considered good practice to call this method when the {@link DrmManagerClient} object
-     * is no longer needed in your application. After release() is called,
-     * {@link DrmManagerClient} is no longer usable since it has lost all of its required resource.
+     * Releases resources associated with the current session of
+     * DrmManagerClient. It is considered good practice to call this method when
+     * the {@link DrmManagerClient} object is no longer needed in your
+     * application. After this method is called, {@link DrmManagerClient} is no
+     * longer usable since it has lost all of its required resource.
      */
-    public void release() {
-        if (mReleased) return;
-        mReleased = true;
-
-        if (mEventHandler != null) {
-            mEventThread.quit();
-            mEventThread = null;
-        }
-        if (mInfoHandler != null) {
-            mInfoThread.quit();
-            mInfoThread = null;
-        }
-        mEventHandler = null;
-        mInfoHandler = null;
-        mOnEventListener = null;
-        mOnInfoListener = null;
-        mOnErrorListener = null;
-        _release(mUniqueId);
+    @Override
+    public void close() {
         mCloseGuard.close();
+        if (mClosed.compareAndSet(false, true)) {
+            if (mEventHandler != null) {
+                mEventThread.quit();
+                mEventThread = null;
+            }
+            if (mInfoHandler != null) {
+                mInfoThread.quit();
+                mInfoThread = null;
+            }
+            mEventHandler = null;
+            mInfoHandler = null;
+            mOnEventListener = null;
+            mOnInfoListener = null;
+            mOnErrorListener = null;
+            _release(mUniqueId);
+        }
+    }
+
+    /**
+     * @deprecated replaced by {@link #close()}.
+     */
+    @Deprecated
+    public void release() {
+        close();
     }
 
     /**