Handle races caused by rapid settings changed broadcasts (e17ce5fb) · Commits · e / os / android_packages_apps_Settings

src/com/android/settings/location/InjectedSetting.java

+49 −5

Original line number	Diff line number	Diff line
		@@ -17,12 +17,17 @@
		package com.android.settings.location;

		import android.content.Intent;
		import android.text.TextUtils;
		import android.util.Log;
		import com.android.internal.annotations.Immutable;
		import com.android.internal.util.Preconditions;

		/**
		* Specifies a setting that is being injected into Settings > Location > Location services.
		*
		* @see android.location.SettingInjectorService
		*/
		@Immutable
		class InjectedSetting {

		/**
		@@ -53,13 +58,30 @@ class InjectedSetting {
		*/
		public final String settingsActivity;

		public InjectedSetting(String packageName, String className,
		private InjectedSetting(String packageName, String className,
		String title, int iconId, String settingsActivity) {
		this.packageName = packageName;
		this.className = className;
		this.title = title;
		this.packageName = Preconditions.checkNotNull(packageName, "packageName");
		this.className = Preconditions.checkNotNull(className, "className");
		this.title = Preconditions.checkNotNull(title, "title");
		this.iconId = iconId;
		this.settingsActivity = settingsActivity;
		this.settingsActivity = Preconditions.checkNotNull(settingsActivity);
		}

		/**
		* Returns a new instance, or null.
		*/
		public static InjectedSetting newInstance(String packageName, String className,
		String title, int iconId, String settingsActivity) {
		if (packageName == null \|\| className == null \|\|
		TextUtils.isEmpty(title) \|\| TextUtils.isEmpty(settingsActivity)) {
		if (Log.isLoggable(SettingsInjector.TAG, Log.WARN)) {
		Log.w(SettingsInjector.TAG, "Illegal setting specification: package="
		+ packageName + ", class=" + className
		+ ", title=" + title + ", settingsActivity=" + settingsActivity);
		}
		return null;
		}
		return new InjectedSetting(packageName, className, title, iconId, settingsActivity);
		}

		@Override
		@@ -81,4 +103,26 @@ class InjectedSetting {
		intent.setClassName(packageName, className);
		return intent;
		}

		@Override
		public boolean equals(Object o) {
		if (this == o) return true;
		if (!(o instanceof InjectedSetting)) return false;

		InjectedSetting that = (InjectedSetting) o;

		return packageName.equals(that.packageName) && className.equals(that.className)
		&& title.equals(that.title) && iconId == that.iconId
		&& settingsActivity.equals(that.settingsActivity);
		}

		@Override
		public int hashCode() {
		int result = packageName.hashCode();
		result = 31 * result + className.hashCode();
		result = 31 * result + title.hashCode();
		result = 31 * result + iconId;
		result = 31 * result + settingsActivity.hashCode();
		return result;
		}
		}

src/com/android/settings/location/LocationSettings.java

+7 −2

Original line number	Diff line number	Diff line
		@@ -31,6 +31,7 @@ import android.preference.PreferenceGroup;
		import android.preference.PreferenceManager;
		import android.preference.PreferenceScreen;
		import android.provider.Settings;
		import android.util.Log;
		import android.view.Gravity;
		import android.widget.CompoundButton;
		import android.widget.Switch;
		@@ -47,6 +48,9 @@ import java.util.List;
		*/
		public class LocationSettings extends LocationSettingsBase
		implements CompoundButton.OnCheckedChangeListener {

		private static final String TAG = "LocationSettings";

		/** Key for preference screen "Mode" */
		private static final String KEY_LOCATION_MODE = "location_mode";
		/** Key for preference category "Recent location requests" */
		@@ -146,8 +150,6 @@ public class LocationSettings extends LocationSettingsBase
		}
		});

		final PreferenceManager preferenceManager = getPreferenceManager();

		PreferenceCategory categoryRecentLocationRequests =
		(PreferenceCategory) root.findPreference(KEY_RECENT_LOCATION_REQUESTS);
		RecentLocationApps recentApps = new RecentLocationApps(activity, mStatsHelper);
		@@ -172,6 +174,9 @@ public class LocationSettings extends LocationSettingsBase
		mReceiver = new BroadcastReceiver() {
		@Override
		public void onReceive(Context context, Intent intent) {
		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, "Received settings change intent: " + intent);
		}
		injector.reloadStatusMessages();
		}
		};

src/com/android/settings/location/SettingsInjector.java

+175 −106

Original line number	Diff line number	Diff line
		@@ -31,18 +31,20 @@ import android.os.Handler;
		import android.os.Message;
		import android.os.Messenger;
		import android.preference.Preference;
		import android.text.TextUtils;
		import android.util.AttributeSet;
		import android.util.Log;
		import android.util.Xml;
		import com.android.settings.R;
		import org.xmlpull.v1.XmlPullParser;
		import org.xmlpull.v1.XmlPullParserException;

		import com.android.settings.R;

		import java.io.IOException;
		import java.util.ArrayList;
		import java.util.HashSet;
		import java.util.Iterator;
		import java.util.LinkedHashSet;
		import java.util.List;
		import java.util.Set;

		/**
		* Adds the preferences specified by the {@link InjectedSetting} objects to a preference group.
		@@ -59,7 +61,7 @@ import java.util.List;
		* {@link SettingInjectorService#UPDATE_INTENT}.
		*/
		class SettingsInjector {
		private static final String TAG = "SettingsInjector";
		static final String TAG = "SettingsInjector";

		private static final long INJECTED_STATUS_UPDATE_TIMEOUT_MILLIS = 1000;

		@@ -79,11 +81,35 @@ class SettingsInjector {
		*/
		public static final String ATTRIBUTES_NAME = "injected-location-setting";

		private Context mContext;
		private StatusLoader mLoader = null;
		/**
		* {@link Message#what} value for starting to load status values
		* in case we aren't already in the process of loading them.
		*/
		private static final int WHAT_RELOAD = 1;

		/**
		* {@link Message#what} value sent after receiving a status message.
		*/
		private static final int WHAT_RECEIVED_STATUS = 2;

		/**
		* {@link Message#what} value sent after the timeout waiting for a status message.
		*/
		private static final int WHAT_TIMEOUT = 3;

		private final Context mContext;

		/**
		* The settings that were injected
		*/
		private final Set<Setting> mSettings;

		private final Handler mHandler;

		public SettingsInjector(Context context) {
		mContext = context;
		mSettings = new HashSet<Setting>();
		mHandler = new StatusLoadingHandler();
		}

		/**
		@@ -168,6 +194,9 @@ class SettingsInjector {
		}
		}

		/**
		* Returns an immutable representation of the static attributes for the setting, or null.
		*/
		private static InjectedSetting parseAttributes(
		String packageName, String className, Resources res, AttributeSet attrs) {

		@@ -175,86 +204,22 @@ class SettingsInjector {
		try {
		// Note that to help guard against malicious string injection, we do not allow dynamic
		// specification of the label (setting title)
		final int labelId = sa.getResourceId(
		android.R.styleable.InjectedLocationSetting_label, 0);
		final String label = sa.getString(android.R.styleable.InjectedLocationSetting_label);
		final int iconId = sa.getResourceId(
		android.R.styleable.InjectedLocationSetting_icon, 0);
		final String settingsActivity =
		sa.getString(android.R.styleable.InjectedLocationSetting_settingsActivity);
		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, "parsed labelId: " + labelId + ", label: " + label
		+ ", iconId: " + iconId);
		Log.d(TAG, "parsed label: " + label + ", iconId: " + iconId
		+ ", settingsActivity: " + settingsActivity);
		}
		if (labelId == 0 \|\| TextUtils.isEmpty(label) \|\| TextUtils.isEmpty(settingsActivity)) {
		return null;
		}
		return new InjectedSetting(packageName, className,
		return InjectedSetting.newInstance(packageName, className,
		label, iconId, settingsActivity);
		} finally {
		sa.recycle();
		}
		}

		private final class StatusLoader {
		private final Intent mIntent;
		private final StatusLoader mPrev;

		private boolean mLoaded = false;

		/**
		* Creates a loader and chains with the previous loader.
		*/
		public StatusLoader(Intent intent, StatusLoader prev) {
		mIntent = intent;
		mPrev = prev;
		}

		/**
		* Clears the loaded flag for the whole chain.
		*/
		private void setNotLoaded() {
		mLoaded = false;
		if (mPrev != null) {
		mPrev.setNotLoaded();
		}
		}

		/**
		* Reloads the whole chain.
		*/
		public void reload() {
		setNotLoaded();
		loadIfNotLoaded();
		}

		/**
		* If the current message hasn't been loaded, loads the status messages
		* and set time out for the next message.
		*/
		public void loadIfNotLoaded() {
		if (mLoaded) {
		return;
		}

		mContext.startService(mIntent);
		if (mPrev != null) {
		Handler handler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
		// Continue with the next item in the chain.
		mPrev.loadIfNotLoaded();
		}
		};
		// Ensure that we start loading the previous setting in the chain if the current
		// setting hasn't loaded before the timeout
		handler.sendMessageDelayed(
		Message.obtain(handler), INJECTED_STATUS_UPDATE_TIMEOUT_MILLIS);
		}
		mLoaded = true;
		}
		}

		/**
		* Gets a list of preferences that other apps have injected.
		*
		@@ -264,17 +229,12 @@ class SettingsInjector {
		public List<Preference> getInjectedSettings() {
		Iterable<InjectedSetting> settings = getSettings();
		ArrayList<Preference> prefs = new ArrayList<Preference>();
		mLoader = null;
		for (InjectedSetting setting : settings) {
		Preference pref = addServiceSetting(prefs, setting);
		Intent intent = createUpdatingIntent(pref, setting, mLoader);
		mLoader = new StatusLoader(intent, mLoader);
		mSettings.add(new Setting(setting, pref));
		}

		// Start a thread to load each list item status.
		if (mLoader != null) {
		mLoader.loadIfNotLoaded();
		}
		reloadStatusMessages();

		return prefs;
		}
		@@ -283,9 +243,10 @@ class SettingsInjector {
		* Reloads the status messages for all the preference items.
		*/
		public void reloadStatusMessages() {
		if (mLoader != null) {
		mLoader.reload();
		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, "reloadingStatusMessages: " + mSettings);
		}
		mHandler.sendMessage(mHandler.obtainMessage(WHAT_RELOAD));
		}

		/**
		@@ -308,12 +269,119 @@ class SettingsInjector {
		}

		/**
		* Creates an Intent to ask the receiver for the current status for the setting, and display it
		* when it replies.
		* Loads the setting status values one at a time. Each load starts a subclass of {@link
		* SettingInjectorService}, so to reduce memory pressure we don't want to load too many at
		* once.
		*/
		private final class StatusLoadingHandler extends Handler {

		/**
		* Settings whose status values need to be loaded. A set is used to prevent redundant loads
		* even if {@link #reloadStatusMessages()} is called many times in rapid succession (for
		* example, if we receive a lot of
		* {@link android.location.SettingInjectorService#UPDATE_INTENT} broadcasts).
		* <p/>
		* We use a linked hash set to ensure that when {@link #reloadStatusMessages()} is called,
		* any settings that haven't been loaded yet will finish loading before any already-loaded
		* messages are loaded again.
		*/
		private LinkedHashSet<Setting> mSettingsToLoad = new LinkedHashSet<Setting>();

		/**
		* Whether we're in the middle of loading settings.
		*/
		private boolean mLoading;

		@Override
		public void handleMessage(Message msg) {
		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, "handleMessage start: " + msg + ", mSettingsToLoad: " + mSettingsToLoad);
		}

		switch (msg.what) {
		case WHAT_RELOAD:
		mSettingsToLoad.addAll(mSettings);
		if (mLoading) {
		// Already waiting for a service to return its status, don't ask a new one
		return;
		}
		mLoading = true;
		break;
		case WHAT_TIMEOUT:
		if (Log.isLoggable(TAG, Log.WARN)) {
		final Setting setting = (Setting) msg.obj;
		setting.timedOut = true;
		Log.w(TAG, "Timed out trying to get status for: " + setting);
		}
		break;
		case WHAT_RECEIVED_STATUS:
		final Setting setting = (Setting) msg.obj;
		if (setting.timedOut) {
		// We've already restarted retrieving the next setting, don't start another
		return;
		}

		// Received the setting without timeout, clear any previous timed out status
		setting.timedOut = false;
		break;
		default:
		throw new IllegalArgumentException("Unexpected what: " + msg);
		}

		// Remove the next setting to load from the queue, if any
		Iterator<Setting> iter = mSettingsToLoad.iterator();
		if (!iter.hasNext()) {
		mLoading = false;
		return;
		}
		Setting setting = iter.next();
		iter.remove();

		// Request the status value
		Intent intent = setting.createUpdatingIntent();
		mContext.startService(intent);

		// Ensure that if receiving the status value takes too long, we start loading the
		// next value anyway
		Message timeoutMsg = obtainMessage(WHAT_TIMEOUT, setting);
		removeMessages(WHAT_TIMEOUT);
		sendMessageDelayed(timeoutMsg, INJECTED_STATUS_UPDATE_TIMEOUT_MILLIS);

		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, "handleMessage end: " + msg + ", mSettingsToLoad: " + mSettingsToLoad);
		}
		}
		}

		/**
		* Represents an injected setting and the corresponding preference.
		*/
		private static Intent createUpdatingIntent(
		final Preference pref, final InjectedSetting info, final StatusLoader prev) {
		final Intent receiverIntent = info.getServiceIntent();
		private final class Setting {

		public final InjectedSetting setting;
		public final Preference preference;
		public boolean timedOut = false;

		private Setting(InjectedSetting setting, Preference preference) {
		this.setting = setting;
		this.preference = preference;
		}

		@Override
		public String toString() {
		return "Setting{" +
		"setting=" + setting +
		", preference=" + preference +
		", timedOut=" + timedOut +
		'}';
		}

		/**
		* Creates an Intent to ask the receiver for the current status for the setting, and display
		* it when it replies.
		*/
		public Intent createUpdatingIntent() {
		final Intent receiverIntent = setting.getServiceIntent();
		Handler handler = new Handler() {
		@Override
		public void handleMessage(Message msg) {
		@@ -321,20 +389,21 @@ class SettingsInjector {
		String status = bundle.getString(SettingInjectorService.STATUS_KEY);
		boolean enabled = bundle.getBoolean(SettingInjectorService.ENABLED_KEY, true);
		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, info + ": received " + msg + ", bundle: " + bundle);
		}
		pref.setSummary(status);
		pref.setEnabled(enabled);
		if (prev != null) {
		prev.loadIfNotLoaded();
		Log.d(TAG, setting + ": received " + msg + ", bundle: " + bundle);
		}
		preference.setSummary(status);
		preference.setEnabled(enabled);
		mHandler.sendMessage(
		mHandler.obtainMessage(WHAT_RECEIVED_STATUS, Setting.this));
		}
		};
		Messenger messenger = new Messenger(handler);
		receiverIntent.putExtra(SettingInjectorService.MESSENGER_KEY, messenger);
		if (Log.isLoggable(TAG, Log.DEBUG)) {
		Log.d(TAG, info + ": sending rcv-intent: " + receiverIntent + ", handler: " + handler);
		Log.d(TAG, setting + ": sending rcv-intent: " + receiverIntent
		+ ", handler: " + handler);
		}
		return receiverIntent;
		}
		}
		}