Add "call" method on ContentProvider.

This permits implementing interfaces which are faster than using
remote Cursors.  It then uses it for Settings & SettingProvider, which
together account for ~50% of total ContentProvider event loop stalls
across Froyo dogfooders.

For fetching Settings this looks like it should reduce average
Settings lookup from 10 ms to 0.4 ms on Sholes, once the
SettingsProvider serves most gets from in-memory cache.  Currently it
brings the Sholes average down from 10ms to 2.5 ms while still using
SQLite queries on each get.

1 files changed, 23 insertions, 1 deletions

diff --git a/core/java/android/content/ContentProvider.java b/core/java/android/content/ContentProvider.java
index 91b1c4e..5fb2aae 100644
--- a/core/java/android/content/ContentProvider.java
+++ b/core/java/android/content/ContentProvider.java
@@ -29,6 +29,7 @@ import android.database.IContentObserver;
 import android.database.SQLException;
 import android.net.Uri;
 import android.os.Binder;
+import android.os.Bundle;
 import android.os.ParcelFileDescriptor;
 import android.os.Process;
 
@@ -217,6 +218,13 @@ public abstract class ContentProvider implements ComponentCallbacks {
             return ContentProvider.this.openAssetFile(uri, mode);
         }
 
+        /**
+         * @hide
+         */
+        public Bundle call(String method, String request, Bundle args) {
+            return ContentProvider.this.call(method, request, args);
+        }
+
         private void enforceReadPermission(Uri uri) {
             final int uid = Binder.getCallingUid();
             if (uid == mMyUid) {
@@ -748,4 +756,18 @@ public abstract class ContentProvider implements ComponentCallbacks {
         }
         return results;
     }
-}
\ No newline at end of file
+
+    /**
+     * @hide -- until interface has proven itself
+     *
+     * Call an provider-defined method.  This can be used to implement
+     * interfaces that are cheaper than using a Cursor.
+     *
+     * @param method Method name to call.  Opaque to framework.
+     * @param request Nullable String argument passed to method.
+     * @param args Nullable Bundle argument passed to method.
+     */
+    public Bundle call(String method, String request, Bundle args) {
+        return null;
+    }
+}