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Commit 75ea64fc authored by Jeff Brown's avatar Jeff Brown
Browse files

Implement a cancelation mechanism for queries. 

Added new API to enable cancelation of SQLite and content provider
queries by means of a CancelationSignal object.  The application
creates a CancelationSignal object and passes it as an argument
to the query.  The cancelation signal can then be used to cancel
the query while it is executing.

If the cancelation signal is raised before the query is executed,
then it is immediately terminated.

Change-Id: If2c76e9a7e56ea5e98768b6d4f225f0a1ca61c61
parent ebc016c0

Android.mk

+1 −0
Original line number Diff line number Diff line
@@ -94,6 +94,7 @@ LOCAL_SRC_FILES += \ 
	core/java/android/bluetooth/IBluetoothHealthCallback.aidl \

	core/java/android/bluetooth/IBluetoothPbap.aidl \

	core/java/android/bluetooth/IBluetoothStateChangeCallback.aidl \

	core/java/android/content/ICancelationSignal.aidl \

	core/java/android/content/IClipboard.aidl \

	core/java/android/content/IContentService.aidl \

	core/java/android/content/IIntentReceiver.aidl \

api/current.txt

+27 −0
Original line number Diff line number Diff line
@@ -4659,7 +4659,9 @@ package android.content { 
  public abstract class AsyncTaskLoader extends android.content.Loader {

    ctor public AsyncTaskLoader(android.content.Context);

    method public boolean cancelLoad();

    method protected boolean isLoadInBackgroundCanceled();

    method public abstract D loadInBackground();

    method protected void onCancelLoadInBackground();

    method public void onCanceled(D);

    method protected D onLoadInBackground();

    method public void setUpdateThrottle(long);
@@ -4701,6 +4703,18 @@ package android.content { 
    method public final void setResultExtras(android.os.Bundle);

  }













  public final class CancelationSignal {













    ctor public CancelationSignal();













    method public void cancel();













    method public boolean isCanceled();













    method public void setOnCancelListener(android.content.CancelationSignal.OnCancelListener);













    method public void throwIfCanceled();













  }

























  public static abstract interface CancelationSignal.OnCancelListener {













    method public abstract void onCancel();













  }



























  public class ClipData implements android.os.Parcelable {















    ctor public ClipData(java.lang.CharSequence, java.lang.String[], android.content.ClipData.Item);















    ctor public ClipData(android.content.ClipDescription, android.content.ClipData.Item);










@@ -4820,6 +4834,7 @@ package android.content {













    method public android.os.ParcelFileDescriptor openPipeHelper(android.net.Uri, java.lang.String, android.os.Bundle, T, android.content.ContentProvider.PipeDataWriter<T>) throws java.io.FileNotFoundException;















    method public android.content.res.AssetFileDescriptor openTypedAssetFile(android.net.Uri, java.lang.String, android.os.Bundle) throws java.io.FileNotFoundException;















    method public abstract android.database.Cursor query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String);













    method public android.database.Cursor query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, android.content.CancelationSignal);















    method protected final void setPathPermissions(android.content.pm.PathPermission[]);















    method protected final void setReadPermission(java.lang.String);















    method protected final void setWritePermission(java.lang.String);









@@ -4843,6 +4858,7 @@ package android.content {













    method public android.os.ParcelFileDescriptor openFile(android.net.Uri, java.lang.String) throws java.io.FileNotFoundException, android.os.RemoteException;















    method public final android.content.res.AssetFileDescriptor openTypedAssetFileDescriptor(android.net.Uri, java.lang.String, android.os.Bundle) throws java.io.FileNotFoundException, android.os.RemoteException;















    method public android.database.Cursor query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String) throws android.os.RemoteException;













    method public android.database.Cursor query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, android.content.CancelationSignal) throws android.os.RemoteException;















    method public boolean release();















    method public int update(android.net.Uri, android.content.ContentValues, java.lang.String, java.lang.String[]) throws android.os.RemoteException;















  }










@@ -4929,6 +4945,7 @@ package android.content {













    method public final java.io.OutputStream openOutputStream(android.net.Uri, java.lang.String) throws java.io.FileNotFoundException;















    method public final android.content.res.AssetFileDescriptor openTypedAssetFileDescriptor(android.net.Uri, java.lang.String, android.os.Bundle) throws java.io.FileNotFoundException;















    method public final android.database.Cursor query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String);













    method public final android.database.Cursor query(android.net.Uri, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, android.content.CancelationSignal);















    method public final void registerContentObserver(android.net.Uri, boolean, android.database.ContentObserver);















    method public static void removePeriodicSync(android.accounts.Account, java.lang.String, android.os.Bundle);















    method public static void removeStatusChangeListener(java.lang.Object);










@@ -5777,6 +5794,11 @@ package android.content {













    method public int getNumSuccessfulYieldPoints();















  }



























  public class OperationCanceledException extends java.lang.RuntimeException {













    ctor public OperationCanceledException();













    ctor public OperationCanceledException(java.lang.String);













  }



























  public class PeriodicSync implements android.os.Parcelable {















    ctor public PeriodicSync(android.accounts.Account, java.lang.String, android.os.Bundle, long);















    method public int describeContents();










@@ -7221,11 +7243,15 @@ package android.database.sqlite {













    method public static android.database.sqlite.SQLiteDatabase openOrCreateDatabase(java.lang.String, android.database.sqlite.SQLiteDatabase.CursorFactory);















    method public static android.database.sqlite.SQLiteDatabase openOrCreateDatabase(java.lang.String, android.database.sqlite.SQLiteDatabase.CursorFactory, android.database.DatabaseErrorHandler);















    method public android.database.Cursor query(boolean, java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String);













    method public android.database.Cursor query(boolean, java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String, android.content.CancelationSignal);















    method public android.database.Cursor query(java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String);















    method public android.database.Cursor query(java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String);















    method public android.database.Cursor queryWithFactory(android.database.sqlite.SQLiteDatabase.CursorFactory, boolean, java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String);













    method public android.database.Cursor queryWithFactory(android.database.sqlite.SQLiteDatabase.CursorFactory, boolean, java.lang.String, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String, android.content.CancelationSignal);















    method public android.database.Cursor rawQuery(java.lang.String, java.lang.String[]);













    method public android.database.Cursor rawQuery(java.lang.String, java.lang.String[], android.content.CancelationSignal);















    method public android.database.Cursor rawQueryWithFactory(android.database.sqlite.SQLiteDatabase.CursorFactory, java.lang.String, java.lang.String[], java.lang.String);













    method public android.database.Cursor rawQueryWithFactory(android.database.sqlite.SQLiteDatabase.CursorFactory, java.lang.String, java.lang.String[], java.lang.String, android.content.CancelationSignal);















    method public static int releaseMemory();















    method public long replace(java.lang.String, java.lang.String, android.content.ContentValues);















    method public long replaceOrThrow(java.lang.String, java.lang.String, android.content.ContentValues) throws android.database.SQLException;










@@ -7347,6 +7373,7 @@ package android.database.sqlite {













    method public java.lang.String getTables();















    method public android.database.Cursor query(android.database.sqlite.SQLiteDatabase, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String);















    method public android.database.Cursor query(android.database.sqlite.SQLiteDatabase, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String);













    method public android.database.Cursor query(android.database.sqlite.SQLiteDatabase, java.lang.String[], java.lang.String, java.lang.String[], java.lang.String, java.lang.String, java.lang.String, java.lang.String, android.content.CancelationSignal);















    method public void setCursorFactory(android.database.sqlite.SQLiteDatabase.CursorFactory);















    method public void setDistinct(boolean);















    method public void setProjectionMap(java.util.Map<java.lang.String, java.lang.String>);

























core/java/android/content/AsyncTaskLoader.java



+20
−0




























Original line number
Diff line number
Diff line








@@ -173,6 +173,7 @@ public abstract class AsyncTaskLoader<D> extends Loader<D> {













                if (DEBUG) Slog.v(TAG, "cancelLoad: cancelled=" + cancelled);















                if (cancelled) {















                    mCancellingTask = mTask;













                    onCancelLoadInBackground();















                }















                mTask = null;















                return cancelled;










@@ -255,6 +256,25 @@ public abstract class AsyncTaskLoader<D> extends Loader<D> {













        return loadInBackground();















    }





























    /**













     * Override this method to try to abort the computation currently taking













     * place on a background thread.













     *













     * Note that when this method is called, it is possible that {@link #loadInBackground}













     * has not started yet or has already completed.













     */













    protected void onCancelLoadInBackground() {













    }



























    /**













     * Returns true if the current execution of {@link #loadInBackground()} is being canceled.













     *













     * @return True if the current execution of {@link #loadInBackground()} is being canceled.













     */













    protected boolean isLoadInBackgroundCanceled() {













        return mCancellingTask != null;













    }





























    /**















     * Locks the current thread until the loader completes the current load















     * operation. Returns immediately if there is no load operation running.

































core/java/android/content/CancelationSignal.java
0 → 100644



+164
−0




























Original line number
Diff line number
Diff line













/*













 * Copyright (C) 2012 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.













 */



























package android.content;



























import android.os.RemoteException;



























/**













 * Provides the ability to cancel an operation in progress.













 */













public final class CancelationSignal {













    private boolean mIsCanceled;













    private OnCancelListener mOnCancelListener;













    private ICancelationSignal mRemote;



























    /**













     * Creates a cancelation signal, initially not canceled.













     */













    public CancelationSignal() {













    }



























    /**













     * Returns true if the operation has been canceled.













     *













     * @return True if the operation has been canceled.













     */













    public boolean isCanceled() {













        synchronized (this) {













            return mIsCanceled;













        }













    }



























    /**













     * Throws {@link OperationCanceledException} if the operation has been canceled.













     *













     * @throws OperationCanceledException if the operation has been canceled.













     */













    public void throwIfCanceled() {













        if (isCanceled()) {













            throw new OperationCanceledException();













        }













    }



























    /**













     * Cancels the operation and signals the cancelation listener.













     * If the operation has not yet started, then it will be canceled as soon as it does.













     */













    public void cancel() {













        synchronized (this) {













            if (!mIsCanceled) {













                mIsCanceled = true;













                if (mOnCancelListener != null) {













                    mOnCancelListener.onCancel();













                }













                if (mRemote != null) {













                    try {













                        mRemote.cancel();













                    } catch (RemoteException ex) {













                    }













                }













            }













        }













    }



























    /**













     * Sets the cancelation listener to be called when canceled.













     * If {@link CancelationSignal#cancel} has already been called, then the provided













     * listener is invoked immediately.













     *













     * The listener is called while holding the cancelation signal's lock which is













     * also held while registering or unregistering the listener.  Because of the lock,













     * it is not possible for the listener to run after it has been unregistered.













     * This design choice makes it easier for clients of {@link CancelationSignal} to













     * prevent race conditions related to listener registration and unregistration.













     *













     * @param listener The cancelation listener, or null to remove the current listener.













     */













    public void setOnCancelListener(OnCancelListener listener) {













        synchronized (this) {













            mOnCancelListener = listener;













            if (mIsCanceled && listener != null) {













                listener.onCancel();













            }













        }













    }



























    /**













     * Sets the remote transport.













     *













     * @param remote The remote transport, or null to remove.













     *













     * @hide













     */













    public void setRemote(ICancelationSignal remote) {













        synchronized (this) {













            mRemote = remote;













            if (mIsCanceled && remote != null) {













                try {













                    remote.cancel();













                } catch (RemoteException ex) {













                }













            }













        }













    }



























    /**













     * Creates a transport that can be returned back to the caller of













     * a Binder function and subsequently used to dispatch a cancelation signal.













     *













     * @return The new cancelation signal transport.













     *













     * @hide













     */













    public static ICancelationSignal createTransport() {













        return new Transport();













    }



























    /**













     * Given a locally created transport, returns its associated cancelation signal.













     *













     * @param transport The locally created transport, or null if none.













     * @return The associated cancelation signal, or null if none.













     *













     * @hide













     */













    public static CancelationSignal fromTransport(ICancelationSignal transport) {













        if (transport instanceof Transport) {













            return ((Transport)transport).mCancelationSignal;













        }













        return null;













    }



























    /**













     * Listens for cancelation.













     */













    public interface OnCancelListener {













        /**













         * Called when {@link CancelationSignal#cancel} is invoked.













         */













        void onCancel();













    }



























    private static final class Transport extends ICancelationSignal.Stub {













        final CancelationSignal mCancelationSignal = new CancelationSignal();



























        @Override













        public void cancel() throws RemoteException {













            mCancelationSignal.cancel();













        }













    }













}
























core/java/android/content/ContentProvider.java



+89
−4




























Original line number
Diff line number
Diff line








@@ -29,6 +29,7 @@ import android.os.Binder;













import android.os.Bundle;















import android.os.ParcelFileDescriptor;















import android.os.Process;













import android.os.RemoteException;















import android.util.Log;































import java.io.File;










@@ -174,28 +175,33 @@ public abstract class ContentProvider implements ComponentCallbacks2 {













            return getContentProvider().getClass().getName();















        }





























        @Override















        public Cursor query(Uri uri, String[] projection,













                String selection, String[] selectionArgs, String sortOrder) {













                String selection, String[] selectionArgs, String sortOrder,













                ICancelationSignal cancelationSignal) {















            enforceReadPermission(uri);













            return ContentProvider.this.query(uri, projection, selection,













                    selectionArgs, sortOrder);













            return ContentProvider.this.query(uri, projection, selection, selectionArgs, sortOrder,













                    CancelationSignal.fromTransport(cancelationSignal));















        }





























        @Override















        public String getType(Uri uri) {















            return ContentProvider.this.getType(uri);















        }











































        @Override















        public Uri insert(Uri uri, ContentValues initialValues) {















            enforceWritePermission(uri);















            return ContentProvider.this.insert(uri, initialValues);















        }





























        @Override















        public int bulkInsert(Uri uri, ContentValues[] initialValues) {















            enforceWritePermission(uri);















            return ContentProvider.this.bulkInsert(uri, initialValues);















        }





























        @Override















        public ContentProviderResult[] applyBatch(ArrayList<ContentProviderOperation> operations)















                throws OperationApplicationException {















            for (ContentProviderOperation operation : operations) {









@@ -210,17 +216,20 @@ public abstract class ContentProvider implements ComponentCallbacks2 {













            return ContentProvider.this.applyBatch(operations);















        }





























        @Override















        public int delete(Uri uri, String selection, String[] selectionArgs) {















            enforceWritePermission(uri);















            return ContentProvider.this.delete(uri, selection, selectionArgs);















        }





























        @Override















        public int update(Uri uri, ContentValues values, String selection,















                String[] selectionArgs) {















            enforceWritePermission(uri);















            return ContentProvider.this.update(uri, values, selection, selectionArgs);















        }





























        @Override















        public ParcelFileDescriptor openFile(Uri uri, String mode)















                throws FileNotFoundException {















            if (mode != null && mode.startsWith("rw")) enforceWritePermission(uri);









@@ -228,6 +237,7 @@ public abstract class ContentProvider implements ComponentCallbacks2 {













            return ContentProvider.this.openFile(uri, mode);















        }





























        @Override















        public AssetFileDescriptor openAssetFile(Uri uri, String mode)















                throws FileNotFoundException {















            if (mode != null && mode.startsWith("rw")) enforceWritePermission(uri);









@@ -235,6 +245,7 @@ public abstract class ContentProvider implements ComponentCallbacks2 {













            return ContentProvider.this.openAssetFile(uri, mode);















        }





























        @Override















        public Bundle call(String method, String arg, Bundle extras) {















            return ContentProvider.this.call(method, arg, extras);















        }









@@ -251,6 +262,11 @@ public abstract class ContentProvider implements ComponentCallbacks2 {













            return ContentProvider.this.openTypedAssetFile(uri, mimeType, opts);















        }





























        @Override













        public ICancelationSignal createCancelationSignal() throws RemoteException {













            return CancelationSignal.createTransport();













        }





























        private void enforceReadPermission(Uri uri) {















            final int uid = Binder.getCallingUid();















            if (uid == mMyUid) {










@@ -540,6 +556,75 @@ public abstract class ContentProvider implements ComponentCallbacks2 {













    public abstract Cursor query(Uri uri, String[] projection,















            String selection, String[] selectionArgs, String sortOrder);





























    /**













     * Implement this to handle query requests from clients with support for cancelation.













     * This method can be called from multiple threads, as described in













     * <a href="{@docRoot}guide/topics/fundamentals/processes-and-threads.html#Threads">Processes













     * and Threads</a>.













     * <p>













     * Example client call:<p>













     * <pre>// Request a specific record.













     * Cursor managedCursor = managedQuery(













                ContentUris.withAppendedId(Contacts.People.CONTENT_URI, 2),













                projection,    // Which columns to return.













                null,          // WHERE clause.













                null,          // WHERE clause value substitution













                People.NAME + " ASC");   // Sort order.</pre>













     * Example implementation:<p>













     * <pre>// SQLiteQueryBuilder is a helper class that creates the













        // proper SQL syntax for us.













        SQLiteQueryBuilder qBuilder = new SQLiteQueryBuilder();



























        // Set the table we're querying.













        qBuilder.setTables(DATABASE_TABLE_NAME);



























        // If the query ends in a specific record number, we're













        // being asked for a specific record, so set the













        // WHERE clause in our query.













        if((URI_MATCHER.match(uri)) == SPECIFIC_MESSAGE){













            qBuilder.appendWhere("_id=" + uri.getPathLeafId());













        }



























        // Make the query.













        Cursor c = qBuilder.query(mDb,













                projection,













                selection,













                selectionArgs,













                groupBy,













                having,













                sortOrder);













        c.setNotificationUri(getContext().getContentResolver(), uri);













        return c;</pre>













     * <p>













     * If you implement this method then you must also implement the version of













     * {@link #query(Uri, String[], String, String[], String)} that does not take a cancelation













     * provider to ensure correct operation on older versions of the Android Framework in













     * which the cancelation signal overload was not available.













     *













     * @param uri The URI to query. This will be the full URI sent by the client;













     *      if the client is requesting a specific record, the URI will end in a record number













     *      that the implementation should parse and add to a WHERE or HAVING clause, specifying













     *      that _id value.













     * @param projection The list of columns to put into the cursor. If













     *      null all columns are included.













     * @param selection A selection criteria to apply when filtering rows.













     *      If null then all rows are included.













     * @param selectionArgs You may include ?s in selection, which will be replaced by













     *      the values from selectionArgs, in order that they appear in the selection.













     *      The values will be bound as Strings.













     * @param sortOrder How the rows in the cursor should be sorted.













     *      If null then the provider is free to define the sort order.













     * @param cancelationSignal A signal to cancel the operation in progress, or null if none.













     * If the operation is canceled, then {@link OperationCanceledException} will be thrown













     * when the query is executed.













     * @return a Cursor or null.













     */













    public Cursor query(Uri uri, String[] projection,













            String selection, String[] selectionArgs, String sortOrder,













            CancelationSignal cancelationSignal) {













        return query(uri, projection, selection, selectionArgs, sortOrder);













    }





























    /**















     * Implement this to handle requests for the MIME type of the data at the















     * given URI.  The returned MIME type should start with