/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package org.mozilla.gecko.sync.synchronizer;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.atomic.AtomicInteger;
import org.mozilla.gecko.sync.Logger;
import org.mozilla.gecko.sync.repositories.InactiveSessionException;
import org.mozilla.gecko.sync.repositories.InvalidSessionTransitionException;
import org.mozilla.gecko.sync.repositories.RepositorySession;
import org.mozilla.gecko.sync.repositories.RepositorySessionBundle;
import org.mozilla.gecko.sync.repositories.delegates.DeferrableRepositorySessionCreationDelegate;
import org.mozilla.gecko.sync.repositories.delegates.DeferredRepositorySessionFinishDelegate;
import org.mozilla.gecko.sync.repositories.delegates.RepositorySessionFinishDelegate;
import android.content.Context;
/**
* I coordinate the moving parts of a sync started by
* {@link Synchronizer#synchronize}.
*
* I flow records twice: first from A to B, and then from B to A. I provide
* fine-grained feedback by calling my delegate's callback methods.
*
* Initialize me by creating me with a Synchronizer and a
* SynchronizerSessionDelegate. Kick things off by calling `init` with two
* RepositorySessionBundles, and then call `synchronize` in your `onInitialized`
* callback.
*
* I always call exactly one of my delegate's `onInitialized` or
* `onSessionError` callback methods from `init`.
*
* I call my delegate's `onSynchronizeSkipped` callback method if there is no
* data to be synchronized in `synchronize`.
*
* In addition, I call `onFetchError`, `onStoreError`, and `onSessionError` when
* I encounter a fetch, store, or session error while synchronizing.
*
* Typically my delegate will call `abort` in its error callbacks, which will
* call my delegate's `onSynchronizeAborted` method and halt the sync.
*
* I always call exactly one of my delegate's `onSynchronized` or
* `onSynchronizeFailed` callback methods if I have not seen an error.
*/
public class SynchronizerSession
extends DeferrableRepositorySessionCreationDelegate
implements RecordsChannelDelegate,
RepositorySessionFinishDelegate {
protected static final String LOG_TAG = "SynchronizerSession";
protected Synchronizer synchronizer;
protected SynchronizerSessionDelegate delegate;
protected Context context;
/*
* Computed during init.
*/
private RepositorySession sessionA;
private RepositorySession sessionB;
private RepositorySessionBundle bundleA;
private RepositorySessionBundle bundleB;
// Bug 726054: just like desktop, we track our last interaction with the server,
// not the last record timestamp that we fetched. This ensures that we don't re-
// download the records we just uploaded, at the cost of skipping any records
// that a concurrently syncing client has uploaded.
private long pendingATimestamp = -1;
private long pendingBTimestamp = -1;
private long storeEndATimestamp = -1;
private long storeEndBTimestamp = -1;
private boolean flowAToBCompleted = false;
private boolean flowBToACompleted = false;
protected final AtomicInteger numInboundRecords = new AtomicInteger(-1);
protected final AtomicInteger numOutboundRecords = new AtomicInteger(-1);
/*
* Public API: constructor, init, synchronize.
*/
public SynchronizerSession(Synchronizer synchronizer, SynchronizerSessionDelegate delegate) {
this.setSynchronizer(synchronizer);
this.delegate = delegate;
}
public Synchronizer getSynchronizer() {
return synchronizer;
}
public void setSynchronizer(Synchronizer synchronizer) {
this.synchronizer = synchronizer;
}
public void init(Context context, RepositorySessionBundle bundleA, RepositorySessionBundle bundleB) {
this.context = context;
this.bundleA = bundleA;
this.bundleB = bundleB;
// Begin sessionA and sessionB, call onInitialized in callbacks.
this.getSynchronizer().repositoryA.createSession(this, context);
}
/**
* Get the number of records fetched from the first repository (usually the
* server, hence inbound).
* <p>
* Valid only after first flow has completed.
*
* @return number of records, or -1 if not valid.
*/
public int getInboundCount() {
return numInboundRecords.get();
}
/**
* Get the number of records fetched from the second repository (usually the
* local store, hence outbound).
* <p>
* Valid only after second flow has completed.
*
* @return number of records, or -1 if not valid.
*/
public int getOutboundCount() {
return numOutboundRecords.get();
}
// These are accessed by `abort` and `synchronize`, both of which are synchronized.
// Guarded by `this`.
protected RecordsChannel channelAToB;
protected RecordsChannel channelBToA;
/**
* Please don't call this until you've been notified with onInitialized.
*/
public synchronized void synchronize() {
numInboundRecords.set(-1);
numOutboundRecords.set(-1);
// First thing: decide whether we should.
if (sessionA.shouldSkip() ||
sessionB.shouldSkip()) {
Logger.info(LOG_TAG, "Session requested skip. Short-circuiting sync.");
sessionA.abort();
sessionB.abort();
this.delegate.onSynchronizeSkipped(this);
return;
}
if (!sessionA.dataAvailable() &&
!sessionB.dataAvailable()) {
Logger.info(LOG_TAG, "Neither session reports data available. Short-circuiting sync.");
sessionA.abort();
sessionB.abort();
this.delegate.onSynchronizeSkipped(this);
return;
}
final SynchronizerSession session = this;
// TODO: failed record handling.
// This is the *second* record channel to flow.
// I, SynchronizerSession, am the delegate for the *second* flow.
channelBToA = new RecordsChannel(this.sessionB, this.sessionA, this);
// This is the delegate for the *first* flow.
RecordsChannelDelegate channelAToBDelegate = new RecordsChannelDelegate() {
public void onFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
session.onFirstFlowCompleted(recordsChannel, fetchEnd, storeEnd);
}
@Override
public void onFlowBeginFailed(RecordsChannel recordsChannel, Exception ex) {
Logger.warn(LOG_TAG, "First RecordsChannel onFlowBeginFailed. Logging session error.", ex);
session.delegate.onSynchronizeFailed(session, ex, "Failed to begin first flow.");
}
@Override
public void onFlowFetchFailed(RecordsChannel recordsChannel, Exception ex) {
Logger.warn(LOG_TAG, "First RecordsChannel onFlowFetchFailed. Logging remote fetch error.", ex);
}
@Override
public void onFlowStoreFailed(RecordsChannel recordsChannel, Exception ex, String recordGuid) {
Logger.warn(LOG_TAG, "First RecordsChannel onFlowStoreFailed. Logging local store error.", ex);
}
@Override
public void onFlowFinishFailed(RecordsChannel recordsChannel, Exception ex) {
Logger.warn(LOG_TAG, "First RecordsChannel onFlowFinishedFailed. Logging session error.", ex);
session.delegate.onSynchronizeFailed(session, ex, "Failed to finish first flow.");
}
};
// This is the *first* channel to flow.
channelAToB = new RecordsChannel(this.sessionA, this.sessionB, channelAToBDelegate);
Logger.trace(LOG_TAG, "Starting A to B flow. Channel is " + channelAToB);
try {
channelAToB.beginAndFlow();
} catch (InvalidSessionTransitionException e) {
onFlowBeginFailed(channelAToB, e);
}
}
/**
* Called after the first flow completes.
* <p>
* By default, any fetch and store failures are ignored.
* @param recordsChannel the <code>RecordsChannel</code> (for error testing).
* @param fetchEnd timestamp when fetches completed.
* @param storeEnd timestamp when stores completed.
*/
public void onFirstFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
Logger.trace(LOG_TAG, "First RecordsChannel onFlowCompleted.");
Logger.debug(LOG_TAG, "Fetch end is " + fetchEnd + ". Store end is " + storeEnd + ". Starting next.");
pendingATimestamp = fetchEnd;
storeEndBTimestamp = storeEnd;
numInboundRecords.set(recordsChannel.getFetchCount());
flowAToBCompleted = true;
channelBToA.flow();
}
/**
* Called after the second flow completes.
* <p>
* By default, any fetch and store failures are ignored.
* @param recordsChannel the <code>RecordsChannel</code> (for error testing).
* @param fetchEnd timestamp when fetches completed.
* @param storeEnd timestamp when stores completed.
*/
public void onSecondFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
Logger.trace(LOG_TAG, "Second RecordsChannel onFlowCompleted.");
Logger.debug(LOG_TAG, "Fetch end is " + fetchEnd + ". Store end is " + storeEnd + ". Finishing.");
pendingBTimestamp = fetchEnd;
storeEndATimestamp = storeEnd;
numOutboundRecords.set(recordsChannel.getFetchCount());
flowBToACompleted = true;
// Finish the two sessions.
try {
this.sessionA.finish(this);
} catch (InactiveSessionException e) {
this.onFinishFailed(e);
return;
}
}
@Override
public void onFlowCompleted(RecordsChannel recordsChannel, long fetchEnd, long storeEnd) {
onSecondFlowCompleted(recordsChannel, fetchEnd, storeEnd);
}
@Override
public void onFlowBeginFailed(RecordsChannel recordsChannel, Exception ex) {
Logger.warn(LOG_TAG, "Second RecordsChannel onFlowBeginFailed. Logging session error.", ex);
this.delegate.onSynchronizeFailed(this, ex, "Failed to begin second flow.");
}
@Override
public void onFlowFetchFailed(RecordsChannel recordsChannel, Exception ex) {
Logger.warn(LOG_TAG, "Second RecordsChannel onFlowFetchFailed. Logging local fetch error.", ex);
}
@Override
public void onFlowStoreFailed(RecordsChannel recordsChannel, Exception ex, String recordGuid) {
Logger.warn(LOG_TAG, "Second RecordsChannel onFlowStoreFailed. Logging remote store error.", ex);
}
@Override
public void onFlowFinishFailed(RecordsChannel recordsChannel, Exception ex) {
Logger.warn(LOG_TAG, "Second RecordsChannel onFlowFinishedFailed. Logging session error.", ex);
this.delegate.onSynchronizeFailed(this, ex, "Failed to finish second flow.");
}
/*
* RepositorySessionCreationDelegate methods.
*/
/**
* I could be called twice: once for sessionA and once for sessionB.
*
* I try to clean up sessionA if it is not null, since the creation of
* sessionB must have failed.
*/
@Override
public void onSessionCreateFailed(Exception ex) {
// Attempt to finish the first session, if the second is the one that failed.
if (this.sessionA != null) {
try {
// We no longer need a reference to our context.
this.context = null;
this.sessionA.finish(this);
} catch (Exception e) {
// Never mind; best-effort finish.
}
}
// We no longer need a reference to our context.
this.context = null;
this.delegate.onSynchronizeFailed(this, ex, "Failed to create session");
}
/**
* I should be called twice: first for sessionA and second for sessionB.
*
* If I am called for sessionB, I call my delegate's `onInitialized` callback
* method because my repository sessions are correctly initialized.
*/
// TODO: some of this "finish and clean up" code can be refactored out.
@Override
public void onSessionCreated(RepositorySession session) {
if (session == null ||
this.sessionA == session) {
// TODO: clean up sessionA.
this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(session), "Failed to create session.");
return;
}
if (this.sessionA == null) {
this.sessionA = session;
// Unbundle.
try {
this.sessionA.unbundle(this.bundleA);
} catch (Exception e) {
this.delegate.onSynchronizeFailed(this, new UnbundleError(e, sessionA), "Failed to unbundle first session.");
// TODO: abort
return;
}
this.getSynchronizer().repositoryB.createSession(this, this.context);
return;
}
if (this.sessionB == null) {
this.sessionB = session;
// We no longer need a reference to our context.
this.context = null;
// Unbundle. We unbundled sessionA when that session was created.
try {
this.sessionB.unbundle(this.bundleB);
} catch (Exception e) {
this.delegate.onSynchronizeFailed(this, new UnbundleError(e, sessionA), "Failed to unbundle second session.");
return;
}
this.delegate.onInitialized(this);
return;
}
// TODO: need a way to make sure we don't call any more delegate methods.
this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(session), "Failed to create session.");
}
/*
* RepositorySessionFinishDelegate methods.
*/
/**
* I could be called twice: once for sessionA and once for sessionB.
*
* If sessionB couldn't be created, I don't fail again.
*/
@Override
public void onFinishFailed(Exception ex) {
if (this.sessionB == null) {
// Ah, it was a problem cleaning up. Never mind.
Logger.warn(LOG_TAG, "Got exception cleaning up first after second session creation failed.", ex);
return;
}
String session = (this.sessionA == null) ? "B" : "A";
this.delegate.onSynchronizeFailed(this, ex, "Finish of session " + session + " failed.");
}
/**
* I should be called twice: first for sessionA and second for sessionB.
*
* If I am called for sessionA, I try to finish sessionB.
*
* If I am called for sessionB, I call my delegate's `onSynchronized` callback
* method because my flows should have completed.
*/
@Override
public void onFinishSucceeded(RepositorySession session,
RepositorySessionBundle bundle) {
Logger.debug(LOG_TAG, "onFinishSucceeded. Flows? " + flowAToBCompleted + ", " + flowBToACompleted);
if (session == sessionA) {
if (flowAToBCompleted) {
Logger.debug(LOG_TAG, "onFinishSucceeded: bumping session A's timestamp to " + pendingATimestamp + " or " + storeEndATimestamp);
bundle.bumpTimestamp(Math.max(pendingATimestamp, storeEndATimestamp));
this.synchronizer.bundleA = bundle;
} else {
// Should not happen!
this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(sessionA), "Failed to finish first session.");
return;
}
if (this.sessionB != null) {
Logger.trace(LOG_TAG, "Finishing session B.");
// On to the next.
try {
this.sessionB.finish(this);
} catch (InactiveSessionException e) {
this.onFinishFailed(e);
return;
}
}
} else if (session == sessionB) {
if (flowBToACompleted) {
Logger.debug(LOG_TAG, "onFinishSucceeded: bumping session B's timestamp to " + pendingBTimestamp + " or " + storeEndBTimestamp);
bundle.bumpTimestamp(Math.max(pendingBTimestamp, storeEndBTimestamp));
this.synchronizer.bundleB = bundle;
Logger.trace(LOG_TAG, "Notifying delegate.onSynchronized.");
this.delegate.onSynchronized(this);
} else {
// Should not happen!
this.delegate.onSynchronizeFailed(this, new UnexpectedSessionException(sessionB), "Failed to finish second session.");
return;
}
} else {
// TODO: hurrrrrr...
}
if (this.sessionB == null) {
this.sessionA = null; // We're done.
}
}
@Override
public RepositorySessionFinishDelegate deferredFinishDelegate(final ExecutorService executor) {
return new DeferredRepositorySessionFinishDelegate(this, executor);
}
}