core/java/android/content/AbstractThreadedSyncAdapter.java - platform/frameworks/base - Git at Google

 /*
  * 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.
  */

 package android.content;

 import android.accounts.Account;
 import android.os.Bundle;
 import android.os.IBinder;
 import android.os.Process;
 import android.os.RemoteException;

 import java.util.concurrent.atomic.AtomicInteger;

 /**
  * An abstract implementation of a SyncAdapter that spawns a thread to invoke a sync operation.
  * If a sync operation is already in progress when a startSync() request is received then an error
  * will be returned to the new request and the existing request will be allowed to continue.
  * When a startSync() is received and there is no sync operation in progress then a thread
  * will be started to run the operation and {@link #onPerformSync} will be invoked on that thread.
  * If a cancelSync() is received that matches an existing sync operation then the thread
  * that is running that sync operation will be interrupted, which will indicate to the thread
  * that the sync has been canceled.
  */
 public abstract class AbstractThreadedSyncAdapter {
     /**
      * Kernel event log tag.  Also listed in data/etc/event-log-tags.
      * @Deprecated
      */
     public static final int LOG_SYNC_DETAILS = 2743;

     private final Context mContext;
     private final AtomicInteger mNumSyncStarts;
     private final ISyncAdapterImpl mISyncAdapterImpl;

     // all accesses to this member variable must be synchronized on mSyncThreadLock
     private SyncThread mSyncThread;
     private final Object mSyncThreadLock = new Object();

     private final boolean mAutoInitialize;

     /**
      * Creates an {@link AbstractThreadedSyncAdapter}.
      * @param context the {@link android.content.Context} that this is running within.
      * @param autoInitialize if true then sync requests that have
      * {@link ContentResolver#SYNC_EXTRAS_INITIALIZE} set will be internally handled by
      * {@link AbstractThreadedSyncAdapter} by calling
      * {@link ContentResolver#setIsSyncable(android.accounts.Account, String, int)} with 1 if it
      * is currently set to <0.
      */
     public AbstractThreadedSyncAdapter(Context context, boolean autoInitialize) {
         mContext = context;
         mISyncAdapterImpl = new ISyncAdapterImpl();
         mNumSyncStarts = new AtomicInteger(0);
         mSyncThread = null;
         mAutoInitialize = autoInitialize;
     }

     public Context getContext() {
         return mContext;
     }

     private class ISyncAdapterImpl extends ISyncAdapter.Stub {
         public void startSync(ISyncContext syncContext, String authority, Account account,
                 Bundle extras) {
             final SyncContext syncContextClient = new SyncContext(syncContext);

             boolean alreadyInProgress;
             // synchronize to make sure that mSyncThread doesn't change between when we
             // check it and when we use it
             synchronized (mSyncThreadLock) {
                 if (mSyncThread == null) {
                     if (mAutoInitialize
                             && extras != null
                             && extras.getBoolean(ContentResolver.SYNC_EXTRAS_INITIALIZE, false)) {
                         if (ContentResolver.getIsSyncable(account, authority) < 0) {
                             ContentResolver.setIsSyncable(account, authority, 1);
                         }
                         syncContextClient.onFinished(new SyncResult());
                         return;
                     }
                     mSyncThread = new SyncThread(
                             "SyncAdapterThread-" + mNumSyncStarts.incrementAndGet(),
                             syncContextClient, authority, account, extras);
                     mSyncThread.start();
                     alreadyInProgress = false;
                 } else {
                     alreadyInProgress = true;
                 }
             }

             // do this outside since we don't want to call back into the syncContext while
             // holding the synchronization lock
             if (alreadyInProgress) {
                 syncContextClient.onFinished(SyncResult.ALREADY_IN_PROGRESS);
             }
         }

         public void cancelSync(ISyncContext syncContext) {
             // synchronize to make sure that mSyncThread doesn't change between when we
             // check it and when we use it
             final SyncThread syncThread;
             synchronized (mSyncThreadLock) {
                 syncThread = mSyncThread;
             }
             if (syncThread != null
                     && syncThread.mSyncContext.getSyncContextBinder() == syncContext.asBinder()) {
                 onSyncCanceled();
             }
         }

         public void initialize(Account account, String authority) throws RemoteException {
             Bundle extras = new Bundle();
             extras.putBoolean(ContentResolver.SYNC_EXTRAS_INITIALIZE, true);
             startSync(null, authority, account, extras);
         }
     }

     /**
      * The thread that invokes {@link AbstractThreadedSyncAdapter#onPerformSync}. It also acquires
      * the provider for this sync before calling onPerformSync and releases it afterwards. Cancel
      * this thread in order to cancel the sync.
      */
     private class SyncThread extends Thread {
         private final SyncContext mSyncContext;
         private final String mAuthority;
         private final Account mAccount;
         private final Bundle mExtras;

         private SyncThread(String name, SyncContext syncContext, String authority,
                 Account account, Bundle extras) {
             super(name);
             mSyncContext = syncContext;
             mAuthority = authority;
             mAccount = account;
             mExtras = extras;
         }

         public void run() {
             Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);

             if (isCanceled()) {
                 return;
             }

             SyncResult syncResult = new SyncResult();
             ContentProviderClient provider = null;
             try {
                 provider = mContext.getContentResolver().acquireContentProviderClient(mAuthority);
                 if (provider != null) {
                     AbstractThreadedSyncAdapter.this.onPerformSync(mAccount, mExtras,
                             mAuthority, provider, syncResult);
                 } else {
                     syncResult.databaseError = true;
                 }
             } finally {
                 if (provider != null) {
                     provider.release();
                 }
                 if (!isCanceled()) {
                     mSyncContext.onFinished(syncResult);
                 }
                 // synchronize so that the assignment will be seen by other threads
                 // that also synchronize accesses to mSyncThread
                 synchronized (mSyncThreadLock) {
                     mSyncThread = null;
                 }
             }
         }

         private boolean isCanceled() {
             return Thread.currentThread().isInterrupted();
         }
     }

     /**
      * @return a reference to the IBinder of the SyncAdapter service.
      */
     public final IBinder getSyncAdapterBinder() {
         return mISyncAdapterImpl.asBinder();
     }

     /**
      * Perform a sync for this account. SyncAdapter-specific parameters may
      * be specified in extras, which is guaranteed to not be null. Invocations
      * of this method are guaranteed to be serialized.
      *
      * @param account the account that should be synced
      * @param extras SyncAdapter-specific parameters
      * @param authority the authority of this sync request
      * @param provider a ContentProviderClient that points to the ContentProvider for this
      *   authority
      * @param syncResult SyncAdapter-specific parameters
      */
     public abstract void onPerformSync(Account account, Bundle extras,
             String authority, ContentProviderClient provider, SyncResult syncResult);

     /**
      * Indicates that a sync operation has been canceled. This will be invoked on a separate
      * thread than the sync thread and so you must consider the multi-threaded implications
      * of the work that you do in this method.
      *
      */
     public void onSyncCanceled() {
         final SyncThread syncThread;
         synchronized (mSyncThreadLock) {
             syncThread = mSyncThread;
         }
         if (syncThread != null) {
             syncThread.interrupt();
         }
     }
 }
	/*
	* 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.
	*/

	package android.content;

	import android.accounts.Account;
	import android.os.Bundle;
	import android.os.IBinder;
	import android.os.Process;
	import android.os.RemoteException;

	import java.util.concurrent.atomic.AtomicInteger;

	/**
	* An abstract implementation of a SyncAdapter that spawns a thread to invoke a sync operation.
	* If a sync operation is already in progress when a startSync() request is received then an error
	* will be returned to the new request and the existing request will be allowed to continue.
	* When a startSync() is received and there is no sync operation in progress then a thread
	* will be started to run the operation and {@link #onPerformSync} will be invoked on that thread.
	* If a cancelSync() is received that matches an existing sync operation then the thread
	* that is running that sync operation will be interrupted, which will indicate to the thread
	* that the sync has been canceled.
	*/
	public abstract class AbstractThreadedSyncAdapter {
	/**
	* Kernel event log tag. Also listed in data/etc/event-log-tags.
	* @Deprecated
	*/
	public static final int LOG_SYNC_DETAILS = 2743;

	private final Context mContext;
	private final AtomicInteger mNumSyncStarts;
	private final ISyncAdapterImpl mISyncAdapterImpl;

	// all accesses to this member variable must be synchronized on mSyncThreadLock
	private SyncThread mSyncThread;
	private final Object mSyncThreadLock = new Object();

	private final boolean mAutoInitialize;

	/**
	* Creates an {@link AbstractThreadedSyncAdapter}.
	* @param context the {@link android.content.Context} that this is running within.
	* @param autoInitialize if true then sync requests that have
	* {@link ContentResolver#SYNC_EXTRAS_INITIALIZE} set will be internally handled by
	* {@link AbstractThreadedSyncAdapter} by calling
	* {@link ContentResolver#setIsSyncable(android.accounts.Account, String, int)} with 1 if it
	* is currently set to <0.
	*/
	public AbstractThreadedSyncAdapter(Context context, boolean autoInitialize) {
	mContext = context;
	mISyncAdapterImpl = new ISyncAdapterImpl();
	mNumSyncStarts = new AtomicInteger(0);
	mSyncThread = null;
	mAutoInitialize = autoInitialize;
	}

	public Context getContext() {
	return mContext;
	}

	private class ISyncAdapterImpl extends ISyncAdapter.Stub {
	public void startSync(ISyncContext syncContext, String authority, Account account,
	Bundle extras) {
	final SyncContext syncContextClient = new SyncContext(syncContext);

	boolean alreadyInProgress;
	// synchronize to make sure that mSyncThread doesn't change between when we
	// check it and when we use it
	synchronized (mSyncThreadLock) {
	if (mSyncThread == null) {
	if (mAutoInitialize
	&& extras != null
	&& extras.getBoolean(ContentResolver.SYNC_EXTRAS_INITIALIZE, false)) {
	if (ContentResolver.getIsSyncable(account, authority) < 0) {
	ContentResolver.setIsSyncable(account, authority, 1);
	}
	syncContextClient.onFinished(new SyncResult());
	return;
	}
	mSyncThread = new SyncThread(
	"SyncAdapterThread-" + mNumSyncStarts.incrementAndGet(),
	syncContextClient, authority, account, extras);
	mSyncThread.start();
	alreadyInProgress = false;
	} else {
	alreadyInProgress = true;
	}
	}

	// do this outside since we don't want to call back into the syncContext while
	// holding the synchronization lock
	if (alreadyInProgress) {
	syncContextClient.onFinished(SyncResult.ALREADY_IN_PROGRESS);
	}
	}

	public void cancelSync(ISyncContext syncContext) {
	// synchronize to make sure that mSyncThread doesn't change between when we
	// check it and when we use it
	final SyncThread syncThread;
	synchronized (mSyncThreadLock) {
	syncThread = mSyncThread;
	}
	if (syncThread != null
	&& syncThread.mSyncContext.getSyncContextBinder() == syncContext.asBinder()) {
	onSyncCanceled();
	}
	}

	public void initialize(Account account, String authority) throws RemoteException {
	Bundle extras = new Bundle();
	extras.putBoolean(ContentResolver.SYNC_EXTRAS_INITIALIZE, true);
	startSync(null, authority, account, extras);
	}
	}

	/**
	* The thread that invokes {@link AbstractThreadedSyncAdapter#onPerformSync}. It also acquires
	* the provider for this sync before calling onPerformSync and releases it afterwards. Cancel
	* this thread in order to cancel the sync.
	*/
	private class SyncThread extends Thread {
	private final SyncContext mSyncContext;
	private final String mAuthority;
	private final Account mAccount;
	private final Bundle mExtras;

	private SyncThread(String name, SyncContext syncContext, String authority,
	Account account, Bundle extras) {
	super(name);
	mSyncContext = syncContext;
	mAuthority = authority;
	mAccount = account;
	mExtras = extras;
	}

	public void run() {
	Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);

	if (isCanceled()) {
	return;
	}

	SyncResult syncResult = new SyncResult();
	ContentProviderClient provider = null;
	try {
	provider = mContext.getContentResolver().acquireContentProviderClient(mAuthority);
	if (provider != null) {
	AbstractThreadedSyncAdapter.this.onPerformSync(mAccount, mExtras,
	mAuthority, provider, syncResult);
	} else {
	syncResult.databaseError = true;
	}
	} finally {
	if (provider != null) {
	provider.release();
	}
	if (!isCanceled()) {
	mSyncContext.onFinished(syncResult);
	}
	// synchronize so that the assignment will be seen by other threads
	// that also synchronize accesses to mSyncThread
	synchronized (mSyncThreadLock) {
	mSyncThread = null;
	}
	}
	}

	private boolean isCanceled() {
	return Thread.currentThread().isInterrupted();
	}
	}

	/**
	* @return a reference to the IBinder of the SyncAdapter service.
	*/
	public final IBinder getSyncAdapterBinder() {
	return mISyncAdapterImpl.asBinder();
	}

	/**
	* Perform a sync for this account. SyncAdapter-specific parameters may
	* be specified in extras, which is guaranteed to not be null. Invocations
	* of this method are guaranteed to be serialized.
	*
	* @param account the account that should be synced
	* @param extras SyncAdapter-specific parameters
	* @param authority the authority of this sync request
	* @param provider a ContentProviderClient that points to the ContentProvider for this
	* authority
	* @param syncResult SyncAdapter-specific parameters
	*/
	public abstract void onPerformSync(Account account, Bundle extras,
	String authority, ContentProviderClient provider, SyncResult syncResult);

	/**
	* Indicates that a sync operation has been canceled. This will be invoked on a separate
	* thread than the sync thread and so you must consider the multi-threaded implications
	* of the work that you do in this method.
	*
	*/
	public void onSyncCanceled() {
	final SyncThread syncThread;
	synchronized (mSyncThreadLock) {
	syncThread = mSyncThread;
	}
	if (syncThread != null) {
	syncThread.interrupt();
	}
	}
	}