gecko/mobile/android/base/sync/GlobalSession.java

842 lines
28 KiB
Java

/* 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;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicLong;
import org.json.simple.parser.ParseException;
import org.mozilla.gecko.sync.crypto.CryptoException;
import org.mozilla.gecko.sync.crypto.KeyBundle;
import org.mozilla.gecko.sync.delegates.ClientsDataDelegate;
import org.mozilla.gecko.sync.delegates.FreshStartDelegate;
import org.mozilla.gecko.sync.delegates.GlobalSessionCallback;
import org.mozilla.gecko.sync.delegates.InfoCollectionsDelegate;
import org.mozilla.gecko.sync.delegates.KeyUploadDelegate;
import org.mozilla.gecko.sync.delegates.MetaGlobalDelegate;
import org.mozilla.gecko.sync.delegates.WipeServerDelegate;
import org.mozilla.gecko.sync.net.BaseResource;
import org.mozilla.gecko.sync.net.HttpResponseObserver;
import org.mozilla.gecko.sync.net.SyncResponse;
import org.mozilla.gecko.sync.net.SyncStorageRecordRequest;
import org.mozilla.gecko.sync.net.SyncStorageRequest;
import org.mozilla.gecko.sync.net.SyncStorageRequestDelegate;
import org.mozilla.gecko.sync.net.SyncStorageResponse;
import org.mozilla.gecko.sync.stage.AndroidBrowserBookmarksServerSyncStage;
import org.mozilla.gecko.sync.stage.AndroidBrowserHistoryServerSyncStage;
import org.mozilla.gecko.sync.stage.CheckPreconditionsStage;
import org.mozilla.gecko.sync.stage.CompletedStage;
import org.mozilla.gecko.sync.stage.EnsureClusterURLStage;
import org.mozilla.gecko.sync.stage.EnsureCrypto5KeysStage;
import org.mozilla.gecko.sync.stage.FennecTabsServerSyncStage;
import org.mozilla.gecko.sync.stage.FetchInfoCollectionsStage;
import org.mozilla.gecko.sync.stage.FetchMetaGlobalStage;
import org.mozilla.gecko.sync.stage.FormHistoryServerSyncStage;
import org.mozilla.gecko.sync.stage.GlobalSyncStage;
import org.mozilla.gecko.sync.stage.GlobalSyncStage.Stage;
import org.mozilla.gecko.sync.stage.NoSuchStageException;
import org.mozilla.gecko.sync.stage.PasswordsServerSyncStage;
import org.mozilla.gecko.sync.stage.SyncClientsEngineStage;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.util.Log;
import ch.boye.httpclientandroidlib.HttpResponse;
public class GlobalSession implements CredentialsSource, PrefsSource, HttpResponseObserver {
private static final String LOG_TAG = "GlobalSession";
public static final String API_VERSION = "1.1";
public static final long STORAGE_VERSION = 5;
public SyncConfiguration config = null;
protected Map<Stage, GlobalSyncStage> stages;
public Stage currentState = Stage.idle;
public final GlobalSessionCallback callback;
private Context context;
private ClientsDataDelegate clientsDelegate;
/*
* Key accessors.
*/
public KeyBundle keyBundleForCollection(String collection) throws NoCollectionKeysSetException {
return config.getCollectionKeys().keyBundleForCollection(collection);
}
/*
* Config passthrough for convenience.
*/
@Override
public String credentials() {
return config.credentials();
}
public URI wboURI(String collection, String id) throws URISyntaxException {
return config.wboURI(collection, id);
}
/*
* Validators.
*/
private static boolean isInvalidString(String s) {
return s == null ||
s.trim().length() == 0;
}
private static boolean anyInvalidStrings(String s, String...strings) {
if (isInvalidString(s)) {
return true;
}
for (String str : strings) {
if (isInvalidString(str)) {
return true;
}
}
return false;
}
public GlobalSession(String userAPI,
String serverURL,
String username,
String password,
String prefsPath,
KeyBundle syncKeyBundle,
GlobalSessionCallback callback,
Context context,
Bundle extras,
ClientsDataDelegate clientsDelegate)
throws SyncConfigurationException, IllegalArgumentException, IOException, ParseException, NonObjectJSONException {
if (callback == null) {
throw new IllegalArgumentException("Must provide a callback to GlobalSession constructor.");
}
if (anyInvalidStrings(username, password)) {
throw new SyncConfigurationException();
}
Logger.info(LOG_TAG, "GlobalSession initialized with bundle " + extras);
URI serverURI;
try {
serverURI = (serverURL == null) ? null : new URI(serverURL);
} catch (URISyntaxException e) {
throw new SyncConfigurationException();
}
if (syncKeyBundle == null ||
syncKeyBundle.getEncryptionKey() == null ||
syncKeyBundle.getHMACKey() == null) {
throw new SyncConfigurationException();
}
this.callback = callback;
this.context = context;
this.clientsDelegate = clientsDelegate;
config = new SyncConfiguration(prefsPath, this);
config.userAPI = userAPI;
config.serverURL = serverURI;
config.username = username;
config.password = password;
config.syncKeyBundle = syncKeyBundle;
registerCommands();
prepareStages();
// TODO: data-driven plan for the sync, referring to prepareStages.
}
protected void registerCommands() {
CommandProcessor processor = CommandProcessor.getProcessor();
processor.registerCommand("resetEngine", new CommandRunner() {
@Override
public void executeCommand(List<String> args) {
HashSet<String> names = new HashSet<String>();
names.add(args.get(0));
resetStagesByName(names);
}
});
processor.registerCommand("resetAll", new CommandRunner() {
@Override
public void executeCommand(List<String> args) {
resetAllStages();
}
});
processor.registerCommand("wipeEngine", new CommandRunner() {
@Override
public void executeCommand(List<String> args) {
HashSet<String> names = new HashSet<String>();
names.add(args.get(0));
wipeStagesByName(names);
}
});
processor.registerCommand("wipeAll", new CommandRunner() {
@Override
public void executeCommand(List<String> args) {
wipeAllStages();
}
});
processor.registerCommand("displayURI", new CommandRunner() {
@Override
public void executeCommand(List<String> args) {
CommandProcessor.getProcessor().displayURI(args, getContext());
}
});
}
protected void prepareStages() {
HashMap<Stage, GlobalSyncStage> stages = new HashMap<Stage, GlobalSyncStage>();
stages.put(Stage.checkPreconditions, new CheckPreconditionsStage(this));
stages.put(Stage.ensureClusterURL, new EnsureClusterURLStage(this));
stages.put(Stage.fetchInfoCollections, new FetchInfoCollectionsStage(this));
stages.put(Stage.fetchMetaGlobal, new FetchMetaGlobalStage(this));
stages.put(Stage.ensureKeysStage, new EnsureCrypto5KeysStage(this));
stages.put(Stage.syncClientsEngine, new SyncClientsEngineStage(this));
stages.put(Stage.syncTabs, new FennecTabsServerSyncStage(this));
stages.put(Stage.syncPasswords, new PasswordsServerSyncStage(this));
stages.put(Stage.syncBookmarks, new AndroidBrowserBookmarksServerSyncStage(this));
stages.put(Stage.syncHistory, new AndroidBrowserHistoryServerSyncStage(this));
stages.put(Stage.syncFormHistory, new FormHistoryServerSyncStage(this));
stages.put(Stage.completed, new CompletedStage(this));
this.stages = Collections.unmodifiableMap(stages);
}
public GlobalSyncStage getSyncStageByName(String name) throws NoSuchStageException {
return getSyncStageByName(Stage.byName(name));
}
public GlobalSyncStage getSyncStageByName(Stage next) throws NoSuchStageException {
GlobalSyncStage stage = stages.get(next);
if (stage == null) {
throw new NoSuchStageException(next);
}
return stage;
}
public Collection<GlobalSyncStage> getSyncStagesByEnum(Collection<Stage> enums) {
ArrayList<GlobalSyncStage> out = new ArrayList<GlobalSyncStage>();
for (Stage name : enums) {
try {
GlobalSyncStage stage = this.getSyncStageByName(name);
out.add(stage);
} catch (NoSuchStageException e) {
Logger.warn(LOG_TAG, "Unable to find stage with name " + name);
}
}
return out;
}
public Collection<GlobalSyncStage> getSyncStagesByName(Collection<String> names) {
ArrayList<GlobalSyncStage> out = new ArrayList<GlobalSyncStage>();
for (String name : names) {
try {
GlobalSyncStage stage = this.getSyncStageByName(name);
out.add(stage);
} catch (NoSuchStageException e) {
Logger.warn(LOG_TAG, "Unable to find stage with name " + name);
}
}
return out;
}
/**
* Advance and loop around the stages of a sync.
* @param current
* @return
* The next stage to execute.
*/
public static Stage nextStage(Stage current) {
int index = current.ordinal() + 1;
int max = Stage.completed.ordinal() + 1;
return Stage.values()[index % max];
}
/**
* Move to the next stage in the syncing process.
*/
public void advance() {
// If we have a backoff, request a backoff and don't advance to next stage.
long existingBackoff = largestBackoffObserved.get();
if (existingBackoff > 0) {
this.abort(null, "Aborting sync because of backoff of " + existingBackoff + " milliseconds.");
return;
}
this.callback.handleStageCompleted(this.currentState, this);
Stage next = nextStage(this.currentState);
GlobalSyncStage nextStage;
try {
nextStage = this.getSyncStageByName(next);
} catch (NoSuchStageException e) {
this.abort(e, "No such stage " + next);
return;
}
this.currentState = next;
Logger.info(LOG_TAG, "Running next stage " + next + " (" + nextStage + ")...");
try {
nextStage.execute();
} catch (Exception ex) {
Logger.warn(LOG_TAG, "Caught exception " + ex + " running stage " + next);
this.abort(ex, "Uncaught exception in stage.");
return;
}
}
private String getSyncID() {
return config.syncID;
}
private String generateSyncID() {
config.syncID = Utils.generateGuid();
return config.syncID;
}
/*
* PrefsSource methods.
*/
@Override
public SharedPreferences getPrefs(String name, int mode) {
return this.getContext().getSharedPreferences(name, mode);
}
public Context getContext() {
return this.context;
}
/**
* Begin a sync.
* <p>
* The caller is responsible for:
* <ul>
* <li>Verifying that any backoffs/minimum next sync requests are respected.</li>
* <li>Ensuring that the device is online.</li>
* <li>Ensuring that dependencies are ready.</li>
* </ul>
*
* @throws AlreadySyncingException
*/
public void start() throws AlreadySyncingException {
if (this.currentState != GlobalSyncStage.Stage.idle) {
throw new AlreadySyncingException(this.currentState);
}
installAsHttpResponseObserver(); // Uninstalled by completeSync or abort.
this.advance();
}
/**
* Stop this sync and start again.
* @throws AlreadySyncingException
*/
protected void restart() throws AlreadySyncingException {
this.currentState = GlobalSyncStage.Stage.idle;
if (callback.shouldBackOff()) {
this.callback.handleAborted(this, "Told to back off.");
return;
}
this.start();
}
public void completeSync() {
uninstallAsHttpResponseObserver();
this.currentState = GlobalSyncStage.Stage.idle;
this.callback.handleSuccess(this);
}
public void abort(Exception e, String reason) {
Logger.warn(LOG_TAG, "Aborting sync: " + reason, e);
uninstallAsHttpResponseObserver();
long existingBackoff = largestBackoffObserved.get();
if (existingBackoff > 0) {
callback.requestBackoff(existingBackoff);
}
this.callback.handleError(this, e);
}
public void handleHTTPError(SyncStorageResponse response, String reason) {
// TODO: handling of 50x (backoff), 401 (node reassignment or auth error).
// Fall back to aborting.
Logger.warn(LOG_TAG, "Aborting sync due to HTTP " + response.getStatusCode());
this.interpretHTTPFailure(response.httpResponse());
this.abort(new HTTPFailureException(response), reason);
}
/**
* Perform appropriate backoff etc. extraction.
*/
public void interpretHTTPFailure(HttpResponse response) {
// TODO: handle permanent rejection.
long responseBackoff = (new SyncResponse(response)).totalBackoffInMilliseconds();
if (responseBackoff > 0) {
callback.requestBackoff(responseBackoff);
}
if (response.getStatusLine() != null && response.getStatusLine().getStatusCode() == 401) {
/*
* Alert our callback we have a 401 on a cluster URL. This GlobalSession
* will fail, but the next one will fetch a new cluster URL and will
* distinguish between "node reassignment" and "user password changed".
*/
callback.informUnauthorizedResponse(this, config.getClusterURL());
}
}
public void fetchInfoCollections(InfoCollectionsDelegate callback) throws URISyntaxException {
if (this.config.infoCollections == null) {
this.config.infoCollections = new InfoCollections(config.infoURL(), credentials());
}
this.config.infoCollections.fetch(callback);
}
public void uploadKeys(CryptoRecord keysRecord,
final KeyUploadDelegate keyUploadDelegate) {
SyncStorageRecordRequest request;
final GlobalSession self = this;
try {
request = new SyncStorageRecordRequest(this.config.keysURI());
} catch (URISyntaxException e) {
keyUploadDelegate.onKeyUploadFailed(e);
return;
}
request.delegate = new SyncStorageRequestDelegate() {
@Override
public String ifUnmodifiedSince() {
return null;
}
@Override
public void handleRequestSuccess(SyncStorageResponse response) {
BaseResource.consumeEntity(response); // We don't need the response at all.
keyUploadDelegate.onKeysUploaded();
}
@Override
public void handleRequestFailure(SyncStorageResponse response) {
self.interpretHTTPFailure(response.httpResponse());
BaseResource.consumeEntity(response); // The exception thrown should not need the body of the response.
keyUploadDelegate.onKeyUploadFailed(new HTTPFailureException(response));
}
@Override
public void handleRequestError(Exception ex) {
keyUploadDelegate.onKeyUploadFailed(ex);
}
@Override
public String credentials() {
return self.credentials();
}
};
keysRecord.setKeyBundle(config.syncKeyBundle);
try {
keysRecord.encrypt();
} catch (UnsupportedEncodingException e) {
keyUploadDelegate.onKeyUploadFailed(e);
return;
} catch (CryptoException e) {
keyUploadDelegate.onKeyUploadFailed(e);
return;
}
request.put(keysRecord);
}
/*
* meta/global callbacks.
*/
public void processMetaGlobal(MetaGlobal global) {
config.metaGlobal = global;
Long storageVersion = global.getStorageVersion();
if (storageVersion < STORAGE_VERSION) {
// Outdated server.
freshStart();
return;
}
if (storageVersion > STORAGE_VERSION) {
// Outdated client!
requiresUpgrade();
return;
}
String remoteSyncID = global.getSyncID();
if (remoteSyncID == null) {
// Corrupt meta/global.
freshStart();
return;
}
String localSyncID = this.getSyncID();
if (!remoteSyncID.equals(localSyncID)) {
// Sync ID has changed. Reset timestamps and fetch new keys.
resetAllStages();
config.purgeCryptoKeys();
config.syncID = remoteSyncID;
}
config.persistToPrefs();
advance();
}
public void processMissingMetaGlobal(MetaGlobal global) {
freshStart();
}
/**
* Do a fresh start then quietly finish the sync, starting another.
*/
protected void freshStart() {
final GlobalSession globalSession = this;
freshStart(this, new FreshStartDelegate() {
@Override
public void onFreshStartFailed(Exception e) {
globalSession.abort(e, "Fresh start failed.");
}
@Override
public void onFreshStart() {
try {
globalSession.config.persistToPrefs();
globalSession.restart();
} catch (Exception e) {
Logger.warn(LOG_TAG, "Got exception when restarting sync after freshStart.", e);
globalSession.abort(e, "Got exception after freshStart.");
}
}
});
}
/**
* Clean the server, aborting the current sync.
*/
protected void freshStart(final GlobalSession session, final FreshStartDelegate freshStartDelegate) {
final String newSyncID = session.generateSyncID();
final String metaURL = session.config.metaURL();
final String credentials = session.credentials();
wipeServer(session, new WipeServerDelegate() {
@Override
public void onWiped(long timestamp) {
session.resetAllStages();
session.config.purgeCryptoKeys();
session.config.persistToPrefs();
MetaGlobal mg = new MetaGlobal(metaURL, credentials);
mg.setSyncID(newSyncID);
mg.setStorageVersion(STORAGE_VERSION);
// It would be good to set the X-If-Unmodified-Since header to `timestamp`
// for this PUT to ensure at least some level of transactionality.
// Unfortunately, the servers don't support it after a wipe right now
// (bug 693893), so we're going to defer this until bug 692700.
mg.upload(new MetaGlobalDelegate() {
@Override
public void handleSuccess(MetaGlobal global, SyncStorageResponse response) {
session.config.metaGlobal = global;
Logger.info(LOG_TAG, "New meta/global uploaded with sync ID " + newSyncID);
// Generate and upload new keys.
try {
session.uploadKeys(CollectionKeys.generateCollectionKeys().asCryptoRecord(), new KeyUploadDelegate() {
@Override
public void onKeysUploaded() {
// Now we can download them.
freshStartDelegate.onFreshStart();
}
@Override
public void onKeyUploadFailed(Exception e) {
Log.e(LOG_TAG, "Got exception uploading new keys.", e);
freshStartDelegate.onFreshStartFailed(e);
}
});
} catch (NoCollectionKeysSetException e) {
Log.e(LOG_TAG, "Got exception generating new keys.", e);
freshStartDelegate.onFreshStartFailed(e);
} catch (CryptoException e) {
Log.e(LOG_TAG, "Got exception generating new keys.", e);
freshStartDelegate.onFreshStartFailed(e);
}
}
@Override
public void handleMissing(MetaGlobal global, SyncStorageResponse response) {
// Shouldn't happen.
Logger.warn(LOG_TAG, "Got 'missing' response uploading new meta/global.");
freshStartDelegate.onFreshStartFailed(new Exception("meta/global missing"));
}
@Override
public void handleFailure(SyncStorageResponse response) {
// TODO: respect backoffs etc.
Logger.warn(LOG_TAG, "Got failure " + response.getStatusCode() + " uploading new meta/global.");
session.interpretHTTPFailure(response.httpResponse());
freshStartDelegate.onFreshStartFailed(new HTTPFailureException(response));
}
@Override
public void handleError(Exception e) {
Logger.warn(LOG_TAG, "Got error uploading new meta/global.", e);
freshStartDelegate.onFreshStartFailed(e);
}
});
}
@Override
public void onWipeFailed(Exception e) {
Logger.warn(LOG_TAG, "Wipe failed.");
freshStartDelegate.onFreshStartFailed(e);
}
});
}
// Note that we do not yet implement wipeRemote: it's only necessary for
// first sync options.
// -- reset local stages, wipe server for each stage *except* clients
// (stages only, not whole server!), send wipeEngine commands to each client.
//
// Similarly for startOver (because we don't receive that notification).
// -- remove client data from server, reset local stages, clear keys, reset
// backoff, clear all prefs, discard credentials.
//
// Change passphrase: wipe entire server, reset client to force upload, sync.
//
// When an engine is disabled: wipe its collections on the server, reupload
// meta/global.
//
// On syncing each stage: if server has engine version 0 or old, wipe server,
// reset client to prompt reupload.
// If sync ID mismatch: take that syncID and reset client.
private void wipeServer(final CredentialsSource credentials, final WipeServerDelegate wipeDelegate) {
SyncStorageRequest request;
final GlobalSession self = this;
try {
request = new SyncStorageRequest(config.storageURL(false));
} catch (URISyntaxException ex) {
Logger.warn(LOG_TAG, "Invalid URI in wipeServer.");
wipeDelegate.onWipeFailed(ex);
return;
}
request.delegate = new SyncStorageRequestDelegate() {
@Override
public String ifUnmodifiedSince() {
return null;
}
@Override
public void handleRequestSuccess(SyncStorageResponse response) {
BaseResource.consumeEntity(response);
wipeDelegate.onWiped(response.normalizedWeaveTimestamp());
}
@Override
public void handleRequestFailure(SyncStorageResponse response) {
Logger.warn(LOG_TAG, "Got request failure " + response.getStatusCode() + " in wipeServer.");
// Process HTTP failures here to pick up backoffs, etc.
self.interpretHTTPFailure(response.httpResponse());
BaseResource.consumeEntity(response); // The exception thrown should not need the body of the response.
wipeDelegate.onWipeFailed(new HTTPFailureException(response));
}
@Override
public void handleRequestError(Exception ex) {
Logger.warn(LOG_TAG, "Got exception in wipeServer.", ex);
wipeDelegate.onWipeFailed(ex);
}
@Override
public String credentials() {
return credentials.credentials();
}
};
request.delete();
}
public void wipeAllStages() {
Logger.info(LOG_TAG, "Wiping all stages.");
// Includes "clients".
this.wipeStagesByEnum(Stage.getNamedStages());
}
public static void wipeStages(Collection<GlobalSyncStage> stages) {
for (GlobalSyncStage stage : stages) {
try {
Logger.info(LOG_TAG, "Wiping " + stage);
stage.wipeLocal();
} catch (Exception e) {
Logger.error(LOG_TAG, "Ignoring wipe failure for stage " + stage, e);
}
}
}
public void wipeStagesByEnum(Collection<Stage> stages) {
GlobalSession.wipeStages(this.getSyncStagesByEnum(stages));
}
public void wipeStagesByName(Collection<String> names) {
GlobalSession.wipeStages(this.getSyncStagesByName(names));
}
public void resetAllStages() {
Logger.info(LOG_TAG, "Resetting all stages.");
// Includes "clients".
this.resetStagesByEnum(Stage.getNamedStages());
}
public static void resetStages(Collection<GlobalSyncStage> stages) {
for (GlobalSyncStage stage : stages) {
try {
Logger.info(LOG_TAG, "Resetting " + stage);
stage.resetLocal();
} catch (Exception e) {
Logger.error(LOG_TAG, "Ignoring reset failure for stage " + stage, e);
}
}
}
public void resetStagesByEnum(Collection<Stage> stages) {
GlobalSession.resetStages(this.getSyncStagesByEnum(stages));
}
public void resetStagesByName(Collection<String> names) {
for (String name : names) {
try {
GlobalSyncStage stage = this.getSyncStageByName(name);
Logger.info(LOG_TAG, "Resetting " + name + "(" + stage + ")");
stage.resetLocal();
} catch (NoSuchStageException e) {
Logger.warn(LOG_TAG, "Cannot reset stage " + name + ": no such stage.");
}
}
}
/**
* Suggest that your Sync client needs to be upgraded to work
* with this server.
*/
public void requiresUpgrade() {
Logger.info(LOG_TAG, "Client outdated storage version; requires update.");
// TODO: notify UI.
}
/**
* If meta/global is missing or malformed, throws a MetaGlobalException.
* Otherwise, returns true if there is an entry for this engine in the
* meta/global "engines" object.
*
* @param engineName the name to check (e.g., "bookmarks").
* @param engineSettings
* if non-null, verify that the server engine settings are congruent
* with this, throwing the appropriate MetaGlobalException if not.
* @return
* true if the engine with the provided name is present in the
* meta/global "engines" object, and verification passed.
*
* @throws MetaGlobalException
*/
public boolean engineIsEnabled(String engineName, EngineSettings engineSettings) throws MetaGlobalException {
if (this.config.metaGlobal == null) {
throw new MetaGlobalNotSetException();
}
if (this.config.metaGlobal.engines == null) {
throw new MetaGlobalMissingEnginesException();
}
ExtendedJSONObject engineEntry;
try {
engineEntry = this.config.metaGlobal.engines.getObject(engineName);
} catch (NonObjectJSONException e) {
Logger.error(LOG_TAG, "Engine field for " + engineName + " in meta/global is not an object.");
throw new MetaGlobalMissingEnginesException();
}
if (engineEntry == null) {
Logger.debug(LOG_TAG, "Engine " + engineName + " not enabled: no meta/global entry.");
return false;
}
if (engineSettings != null) {
MetaGlobal.verifyEngineSettings(engineEntry, engineSettings);
}
return true;
}
public ClientsDataDelegate getClientsDelegate() {
return this.clientsDelegate;
}
/**
* The longest backoff observed to date; -1 means no backoff observed.
*/
protected final AtomicLong largestBackoffObserved = new AtomicLong(-1);
/**
* Reset any observed backoff and start observing HTTP responses for backoff
* requests.
*/
protected void installAsHttpResponseObserver() {
Logger.debug(LOG_TAG, "Installing " + this + " as BaseResource HttpResponseObserver.");
BaseResource.setHttpResponseObserver(this);
largestBackoffObserved.set(-1);
}
/**
* Stop observing HttpResponses for backoff requests.
*/
protected void uninstallAsHttpResponseObserver() {
Logger.debug(LOG_TAG, "Uninstalling " + this + " as BaseResource HttpResponseObserver.");
BaseResource.setHttpResponseObserver(null);
}
/**
* Observe all HTTP response for backoff requests on all status codes, not just errors.
*/
@Override
public void observeHttpResponse(HttpResponse response) {
long responseBackoff = (new SyncResponse(response)).totalBackoffInMilliseconds(); // TODO: don't allocate object?
if (responseBackoff <= 0) {
return;
}
Logger.debug(LOG_TAG, "Observed " + responseBackoff + " millisecond backoff request.");
while (true) {
long existingBackoff = largestBackoffObserved.get();
if (existingBackoff >= responseBackoff) {
return;
}
if (largestBackoffObserved.compareAndSet(existingBackoff, responseBackoff)) {
return;
}
}
}
}