Use ashmem for CursorWindows.

Bug: 5332296

The memory dealer introduces additional delays for reclaiming
the memory owned by CursorWindows because the Binder object must
be finalized.  Using ashmem instead gives CursorWindow more
direct control over the lifetime of the shared memory region.

The provider now allocates the CursorWindows and returns them
to clients with a read-only protection bit set on the ashmem
region.

Improved the encapsulation of CursorWindow.  Callers shouldn't
need to care about details like how string fields are allocated.

Removed the compile-time configuration of string and numeric
storage modes to remove some dead weight.

Change-Id: I07c2bc2a9c573d7e435dcaecd269d25ea9807acd

1 files changed, 51 insertions, 59 deletions

diff --git a/core/java/android/content/ContentProviderNative.java b/core/java/android/content/ContentProviderNative.java
index 064755e..b089bf2 100644
--- a/core/java/android/content/ContentProviderNative.java
+++ b/core/java/android/content/ContentProviderNative.java
@@ -108,21 +108,22 @@ abstract public class ContentProviderNative extends Binder implements IContentPr
                     String sortOrder = data.readString();
                     IContentObserver observer = IContentObserver.Stub.asInterface(
                             data.readStrongBinder());
-                    CursorWindow window = CursorWindow.CREATOR.createFromParcel(data);
 
                     Cursor cursor = query(url, projection, selection, selectionArgs, sortOrder);
                     if (cursor != null) {
                         CursorToBulkCursorAdaptor adaptor = new CursorToBulkCursorAdaptor(
-                                cursor, observer, getProviderName(), window);
+                                cursor, observer, getProviderName());
                         final IBinder binder = adaptor.asBinder();
                         final int count = adaptor.count();
                         final int index = BulkCursorToCursorAdaptor.findRowIdColumnIndex(
                                 adaptor.getColumnNames());
+                        final boolean wantsAllOnMoveCalls = adaptor.getWantsAllOnMoveCalls();
 
                         reply.writeNoException();
                         reply.writeStrongBinder(binder);
                         reply.writeInt(count);
                         reply.writeInt(index);
+                        reply.writeInt(wantsAllOnMoveCalls ? 1 : 0);
                     } else {
                         reply.writeNoException();
                         reply.writeStrongBinder(null);
@@ -324,67 +325,58 @@ final class ContentProviderProxy implements IContentProvider
 
     public Cursor query(Uri url, String[] projection, String selection,
             String[] selectionArgs, String sortOrder) throws RemoteException {
-        CursorWindow window = new CursorWindow(false /* window will be used remotely */);
+        BulkCursorToCursorAdaptor adaptor = new BulkCursorToCursorAdaptor();
+        Parcel data = Parcel.obtain();
+        Parcel reply = Parcel.obtain();
         try {
-            BulkCursorToCursorAdaptor adaptor = new BulkCursorToCursorAdaptor();
-            Parcel data = Parcel.obtain();
-            Parcel reply = Parcel.obtain();
-            try {
-                data.writeInterfaceToken(IContentProvider.descriptor);
-
-                url.writeToParcel(data, 0);
-                int length = 0;
-                if (projection != null) {
-                    length = projection.length;
-                }
-                data.writeInt(length);
-                for (int i = 0; i < length; i++) {
-                    data.writeString(projection[i]);
-                }
-                data.writeString(selection);
-                if (selectionArgs != null) {
-                    length = selectionArgs.length;
-                } else {
-                    length = 0;
-                }
-                data.writeInt(length);
-                for (int i = 0; i < length; i++) {
-                    data.writeString(selectionArgs[i]);
-                }
-                data.writeString(sortOrder);
-                data.writeStrongBinder(adaptor.getObserver().asBinder());
-                window.writeToParcel(data, 0);
-
-                mRemote.transact(IContentProvider.QUERY_TRANSACTION, data, reply, 0);
-
-                DatabaseUtils.readExceptionFromParcel(reply);
-
-                IBulkCursor bulkCursor = BulkCursorNative.asInterface(reply.readStrongBinder());
-                if (bulkCursor != null) {
-                    int rowCount = reply.readInt();
-                    int idColumnPosition = reply.readInt();
-                    adaptor.initialize(bulkCursor, rowCount, idColumnPosition);
-                } else {
-                    adaptor.close();
-                    adaptor = null;
-                }
-                return adaptor;
-            } catch (RemoteException ex) {
-                adaptor.close();
-                throw ex;
-            } catch (RuntimeException ex) {
+            data.writeInterfaceToken(IContentProvider.descriptor);
+
+            url.writeToParcel(data, 0);
+            int length = 0;
+            if (projection != null) {
+                length = projection.length;
+            }
+            data.writeInt(length);
+            for (int i = 0; i < length; i++) {
+                data.writeString(projection[i]);
+            }
+            data.writeString(selection);
+            if (selectionArgs != null) {
+                length = selectionArgs.length;
+            } else {
+                length = 0;
+            }
+            data.writeInt(length);
+            for (int i = 0; i < length; i++) {
+                data.writeString(selectionArgs[i]);
+            }
+            data.writeString(sortOrder);
+            data.writeStrongBinder(adaptor.getObserver().asBinder());
+
+            mRemote.transact(IContentProvider.QUERY_TRANSACTION, data, reply, 0);
+
+            DatabaseUtils.readExceptionFromParcel(reply);
+
+            IBulkCursor bulkCursor = BulkCursorNative.asInterface(reply.readStrongBinder());
+            if (bulkCursor != null) {
+                int rowCount = reply.readInt();
+                int idColumnPosition = reply.readInt();
+                boolean wantsAllOnMoveCalls = reply.readInt() != 0;
+                adaptor.initialize(bulkCursor, rowCount, idColumnPosition, wantsAllOnMoveCalls);
+            } else {
                 adaptor.close();
-                throw ex;
-            } finally {
-                data.recycle();
-                reply.recycle();
+                adaptor = null;
             }
+            return adaptor;
+        } catch (RemoteException ex) {
+            adaptor.close();
+            throw ex;
+        } catch (RuntimeException ex) {
+            adaptor.close();
+            throw ex;
         } finally {
-            // We close the window now because the cursor adaptor does not
-            // take ownership of the window until the first call to onMove.
-            // The adaptor will obtain a fresh reference to the window when
-            // it is filled.
-            window.close();
+            data.recycle();
+            reply.recycle();
         }
     }