path: root/navit/android/src/org/navitproject/navit/NavitTraff.java

/*
 * Navit, a modular navigation system.
 * Copyright (C) 2005-2018 Navit Team
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 */

package org.navitproject.navit;

import android.Manifest;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.IntentFilter.MalformedMimeTypeException;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;

import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

/**
 * The TraFF receiver implementation.
 *
 * <p>This class registers the broadcast receiver for TraFF feeds, polls all registered sources once on creation,
 * receives TraFF feeds and forwards them to the traffic module for processing.</p>
 */
public class NavitTraff extends BroadcastReceiver {

    private static final String ACTION_TRAFF_GET_CAPABILITIES = "org.traffxml.traff.GET_CAPABILITIES";
    private static final String ACTION_TRAFF_HEARTBEAT = "org.traffxml.traff.HEARTBEAT";
    private static final String ACTION_TRAFF_FEED = "org.traffxml.traff.FEED";
    private static final String ACTION_TRAFF_POLL = "org.traffxml.traff.POLL";
    private static final String ACTION_TRAFF_SUBSCRIBE = "org.traffxml.traff.SUBSCRIBE";
    private static final String ACTION_TRAFF_SUBSCRIPTION_CHANGE = "org.traffxml.traff.SUBSCRIPTION_CHANGE";
    private static final String ACTION_TRAFF_UNSUBSCRIBE = "org.traffxml.traff.UNSUBSCRIBE";
    private static final String COLUMN_DATA = "data";
    private static final String CONTENT_SCHEMA = "content";
    private static final String[] ERROR_STRINGS = {
            "unknown (0)",
            "invalid request (1)",
            "subscription rejected by the source (2)",
            "requested area not covered (3)",
            "requested area partially covered (4)",
            "subscription ID not recognized by the source (5)",
            "unknown (6)",
            "source reported an internal error (7)"
    };
    private static final String EXTRA_CAPABILITIES = "capabilities";
    private static final String EXTRA_FEED = "feed";
    private static final String EXTRA_FILTER_LIST = "filter_list";
    private static final String EXTRA_PACKAGE = "package";
    private static final String EXTRA_SUBSCRIPTION_ID = "subscription_id";
    private static final String MIME_TYPE_TRAFF = "vnd.android.cursor.dir/org.traffxml.message";
    private static final int RESULT_OK = -1;
    private static final int RESULT_INTERNAL_ERROR = 7;
    private static final int RESULT_INVALID = 1;
    private static final int RESULT_SUBSCRIPTION_REJECTED = 2;
    private static final int RESULT_NOT_COVERED = 3;
    private static final int RESULT_PARTIALLY_COVERED = 4;
    private static final int RESULT_SUBSCRIPTION_UNKNOWN = 5;
    private static final String TAG = "NavitTraff";
    private final long mCbid;

    private final Context context;

    /** Active subscriptions (key is the subscription ID, value is the package ID). */
    private Map<String, String> subscriptions = new HashMap<String, String>();

    /**
     * Forwards a newly received TraFF feed to the traffic module for processing.
     *
     * <p>This is called when a TraFF feed is received.</p>
     *
     * @param id The identifier for the native callback implementation
     * @param feed The TraFF feed
     */
    public native void onFeedReceived(long id, String feed);

    /**
     * Creates a new {@code NavitTraff} instance.
     *
     * <p>Creating a new {@code NavitTraff} instance registers a broadcast receiver for TraFF broadcasts and polls all
     * registered sources once to ensure we have messages which were received by these sources before we started up.</p>
     *
     * @param context The context
     * @param cbid The callback identifier for the native method to call upon receiving a feed
     */
    NavitTraff(Context context, long cbid) {
        this.mCbid = cbid;
        this.context = context.getApplicationContext();

        /* An intent filter for TraFF 0.7 events. */
        IntentFilter traffFilter07 = new IntentFilter();
        traffFilter07.addAction(ACTION_TRAFF_FEED);

        /* An intent filter for TraFF 0.8 events. */
        IntentFilter traffFilter08 = new IntentFilter();
        traffFilter08.addAction(ACTION_TRAFF_FEED);
        traffFilter08.addDataScheme(CONTENT_SCHEMA);
        try {
            traffFilter08.addDataType(MIME_TYPE_TRAFF);
        } catch (MalformedMimeTypeException e) {
            // as long as the constant is a well-formed MIME type, this exception never gets thrown
            e.printStackTrace();
        }

        this.context.registerReceiver(this, traffFilter07);
        this.context.registerReceiver(this, traffFilter08);

        /* Broadcast a poll intent to all TraFF 0.7-only receivers */
        Intent outIntent = new Intent(ACTION_TRAFF_POLL);
        PackageManager pm = this.context.getPackageManager();
        List<ResolveInfo> receivers07 = pm.queryBroadcastReceivers(outIntent, 0);
        List<ResolveInfo> receivers08 = pm.queryBroadcastReceivers(new Intent(ACTION_TRAFF_GET_CAPABILITIES), 0);
        if (receivers07 != null) {
            /* get receivers which support only TraFF 0.7 and poll them */
            if (receivers08 != null)
                receivers07.removeAll(receivers08);
            for (ResolveInfo receiver : receivers07) {
                ComponentName cn = new ComponentName(receiver.activityInfo.applicationInfo.packageName,
                        receiver.activityInfo.name);
                outIntent = new Intent(ACTION_TRAFF_POLL);
                outIntent.setComponent(cn);
                this.context.sendBroadcast(outIntent, Manifest.permission.ACCESS_COARSE_LOCATION);
            }
        }
    }

    void close() {
        for (Map.Entry<String, String> subscription : subscriptions.entrySet()) {
            Bundle extras = new Bundle();
            extras.putString(EXTRA_SUBSCRIPTION_ID, subscription.getKey());
            sendTraffIntent(this.context, ACTION_TRAFF_UNSUBSCRIBE, null, extras, subscription.getValue(),
                    Manifest.permission.ACCESS_COARSE_LOCATION, this);
        }
        this.context.unregisterReceiver(this);
    }

    void onFilterUpdate(String filterList) {
        /* change existing subscriptions */
        for (Map.Entry<String, String> entry : subscriptions.entrySet()) {
            Log.d(TAG, String.format("changing subscription %s (%s)", entry.getKey(), entry.getValue()));
            Bundle extras = new Bundle();
            extras.putString(EXTRA_SUBSCRIPTION_ID, entry.getKey());
            extras.putString(EXTRA_FILTER_LIST, filterList);
            sendTraffIntent(context, ACTION_TRAFF_SUBSCRIPTION_CHANGE, null, extras,
                    entry.getValue(),
                    Manifest.permission.ACCESS_COARSE_LOCATION, this);
        }

        /* set up missing subscriptions */
        PackageManager pm = this.context.getPackageManager();
        List<ResolveInfo> receivers = pm.queryBroadcastReceivers(new Intent(ACTION_TRAFF_GET_CAPABILITIES), 0);
        if (receivers != null) {
            /* filter out receivers to which we are already subscribed */
            Iterator<ResolveInfo> iter = receivers.iterator();
            while (iter.hasNext()) {
                ResolveInfo receiver = iter.next();
                if (subscriptions.containsValue(receiver.activityInfo.applicationInfo.packageName))
                    iter.remove();
            }

            for (ResolveInfo receiver : receivers) {
                Log.d(TAG, "subscribing to " + receiver.activityInfo.applicationInfo.packageName);
                Bundle extras = new Bundle();
                extras.putString(EXTRA_PACKAGE, context.getPackageName());
                extras.putString(EXTRA_FILTER_LIST, filterList);
                sendTraffIntent(context, ACTION_TRAFF_SUBSCRIBE, null, extras,
                        receiver.activityInfo.applicationInfo.packageName,
                        Manifest.permission.ACCESS_COARSE_LOCATION, this);
            }
        }
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent != null) {
            if (intent.getAction().equals(ACTION_TRAFF_FEED)) {
                Uri uri = intent.getData();
                if (uri != null) {
                    /* 0.8 feed */
                    String subscriptionId = intent.getStringExtra(EXTRA_SUBSCRIPTION_ID);
                    if (subscriptions.containsKey(subscriptionId))
                        fetchMessages(context, uri);
                    else {
                        /*
                         * If we don’t recognize the subscription, skip processing and unsubscribe.
                         * Note: if EXTRA_PACKAGE is not set, sendTraffIntent() sends the request to every
                         * manifest-declared receiver which handles the request.
                         */
                        Log.d(TAG,
                                String.format("got a feed from %s for unknown subscription %s, URI %s; unsubscribing",
                                intent.getStringExtra(EXTRA_PACKAGE), subscriptionId, uri));
                        Bundle extras = new Bundle();
                        extras.putString(EXTRA_SUBSCRIPTION_ID, subscriptionId);
                        sendTraffIntent(context, ACTION_TRAFF_UNSUBSCRIBE, null, extras,
                                intent.getStringExtra(EXTRA_PACKAGE),
                                Manifest.permission.ACCESS_COARSE_LOCATION, this);
                    }
                } else {
                    /* 0.7 feed */
                    String packageName = intent.getStringExtra(EXTRA_PACKAGE);
                    /*
                     * If the feed comes from a TraFF 0.8+ source and we are subscribed, skip it.
                     * As a side effect of the current implementation, if a “bilingual” TraFF 0.7/0.8
                     * source sends a broadcast feed before we have subscribed to it, we would process
                     * the whole feed first, and then subscribe to a subset of that data.
                     * If that turns out to be an issue, we would need to detect TraFF 0.8-capable
                     * sources and discard broadcast feeds from them.
                     */
                    if ((packageName != null) && subscriptions.containsValue(packageName))
                        return;
                    String feed = intent.getStringExtra(EXTRA_FEED);
                    if (feed == null) {
                        Log.w(this.getClass().getSimpleName(), "empty feed, ignoring");
                    } else {
                        onFeedReceived(mCbid, feed);
                    }
                } // uri != null
            } else if (intent.getAction().equals(ACTION_TRAFF_SUBSCRIBE)) {
                if (this.getResultCode() != RESULT_OK) {
                    Bundle extras = this.getResultExtras(true);
                    if (extras != null)
                        Log.e(this.getClass().getSimpleName(), String.format("subscription to %s failed, %s",
                                extras.getString(EXTRA_PACKAGE), formatTraffError(this.getResultCode())));
                    else
                        Log.e(this.getClass().getSimpleName(), String.format("subscription failed, %s",
                                formatTraffError(this.getResultCode())));
                    return;
                }
                Bundle extras = this.getResultExtras(true);
                String data = this.getResultData();
                String packageName = extras.getString(EXTRA_PACKAGE);
                String subscriptionId = extras.getString(EXTRA_SUBSCRIPTION_ID);
                if (subscriptionId == null) {
                    Log.e(this.getClass().getSimpleName(),
                            String.format("subscription to %s failed: no subscription ID returned", packageName));
                    return;
                } else if (packageName == null) {
                    Log.e(this.getClass().getSimpleName(), "subscription failed: no package name");
                    return;
                } else if (data == null) {
                    Log.w(this.getClass().getSimpleName(),
                            String.format("subscription to %s successful (ID: %s) but no content URI was supplied. "
                                    + "This is an issue with the source and may result in delayed message retrieval.",
                                    packageName, subscriptionId));
                    subscriptions.put(subscriptionId, packageName);
                    return;
                }
                Log.d(TAG, "subscription to " + packageName + " successful, ID: " + subscriptionId);
                subscriptions.put(subscriptionId, packageName);
                fetchMessages(context, Uri.parse(data));
            } else if (intent.getAction().equals(ACTION_TRAFF_SUBSCRIPTION_CHANGE)) {
                if (this.getResultCode() != RESULT_OK) {
                    Bundle extras = this.getResultExtras(true);
                    if (extras != null)
                        Log.e(this.getClass().getSimpleName(),
                                String.format("subscription change for %s failed: %s",
                                        extras.getString(EXTRA_SUBSCRIPTION_ID),
                                        formatTraffError(this.getResultCode())));
                    else
                        Log.e(this.getClass().getSimpleName(),
                                String.format("subscription change failed: %s",
                                        formatTraffError(this.getResultCode())));
                    return;
                }
                Bundle extras = intent.getExtras();
                String data = this.getResultData();
                String subscriptionId = extras.getString(EXTRA_SUBSCRIPTION_ID);
                if (subscriptionId == null) {
                    Log.w(this.getClass().getSimpleName(),
                            "subscription change successful but the source did not specify the subscription ID. "
                                    + "This is an issue with the source and may result in delayed message retrieval. "
                                    + "URI: " + data);
                    return;
                } else if (data == null) {
                    Log.w(this.getClass().getSimpleName(),
                            String.format("subscription change for %s successful but no content URI was supplied. "
                                    + "This is an issue with the source and may result in delayed message retrieval.",
                                    subscriptionId));
                    return;
                } else if (!subscriptions.containsKey(subscriptionId)) {
                    Log.e(this.getClass().getSimpleName(),
                            "subscription change failed: unknown subscription ID " + subscriptionId);
                    return;
                }
                Log.d(TAG, "subscription change for " + subscriptionId + " successful");
                fetchMessages(context, Uri.parse(data));
            } else if (intent.getAction().equals(ACTION_TRAFF_UNSUBSCRIBE)) {
                /*
                 * If we ever unsubscribe for reasons other than that we are shutting down or got a feed for
                 * a subscription we don’t recognize, or if we start keeping a persistent list of
                 * subscriptions, we need to delete the subscription from our list. Until then, there is
                 * nothing to do here: either the subscription isn’t in the list, or we are about to shut
                 * down and the whole list is about to get discarded.
                 */
            } else if (intent.getAction().equals(ACTION_TRAFF_HEARTBEAT)) {
                String subscriptionId = intent.getStringExtra(EXTRA_SUBSCRIPTION_ID);
                if (subscriptions.containsKey(subscriptionId)) {
                    Log.d(TAG,
                            String.format("got a heartbeat from %s for subscription %s; sending result",
                            intent.getStringExtra(EXTRA_PACKAGE), subscriptionId));
                    this.setResult(RESULT_OK, null, null);
                } else {
                    /*
                     * If we don’t recognize the subscription, skip reply and unsubscribe.
                     * Note: if EXTRA_PACKAGE is not set, sendTraffIntent() sends the request to every
                     * manifest-declared receiver which handles the request.
                     */
                    Log.d(TAG,
                            String.format("got a heartbeat from %s for unknown subscription %s; unsubscribing",
                            intent.getStringExtra(EXTRA_PACKAGE), subscriptionId));
                    Bundle extras = new Bundle();
                    extras.putString(EXTRA_SUBSCRIPTION_ID, subscriptionId);
                    sendTraffIntent(context, ACTION_TRAFF_UNSUBSCRIBE, null, extras,
                            intent.getStringExtra(EXTRA_PACKAGE),
                            Manifest.permission.ACCESS_COARSE_LOCATION, this);
                }
            } // intent.getAction()
        } // intent != null
    }

    /**
     * Fetches messages from a content provider.
     *
     * @param context The context to use for the content resolver
     * @param uri The content provider URI
     */
    private void fetchMessages(Context context, Uri uri) {
        try {
            Cursor cursor = context.getContentResolver().query(uri, new String[] {COLUMN_DATA}, null, null, null);
            if (cursor == null)
                return;
            if (cursor.getCount() < 1) {
                cursor.close();
                return;
            }
            StringBuilder builder = new StringBuilder("<feed>\n");
            while (cursor.moveToNext())
                builder.append(cursor.getString(cursor.getColumnIndex(COLUMN_DATA))).append("\n");
            builder.append("</feed>");
            cursor.close();
            onFeedReceived(mCbid, builder.toString());
        } catch (Exception e) {
            Log.w(TAG, String.format("Unable to fetch messages from %s", uri.toString()), e);
            e.printStackTrace();
        }
    }

    /**
     * Sends a TraFF intent to a source.  This encapsulates most of the low-level Android handling.
     *
     * <p>If the recipient specified in {@code packageName} declares multiple receivers for the intent in its
     * manifest, a separate intent will be delivered to each of them. The intent will not be delivered to
     * receivers registered at runtime.
     *
     * <p>All intents are sent as explicit ordered broadcasts. This means two things:
     *
     * <p>Any app which declares a matching receiver in its manifest will be woken up to process the intent.
     * This works even with certain Android 7 builds which restrict intent delivery to apps which are not
     * currently running.
     *
     * <p>It is safe for the recipient to unconditionally set result data. If the recipient does not set result
     * data, the result will have a result code of {@link #RESULT_INTERNAL_ERROR}, no data and no extras.
     *
     * @param context The context
     * @param action The intent action.
     * @param data The intent data (for TraFF, this is the content provider URI), or null
     * @param extras The extras for the intent
     * @param packageName The package name for the recipient, or null to deliver the intent to all matching receivers
     * @param receiverPermission A permission which the recipient must hold, or null if not required
     * @param resultReceiver A BroadcastReceiver which will receive the result for the intent
     */
    /* From traff-consumer-android, by the same author and re-licensed under GPL2 for Navit */
    public static void sendTraffIntent(Context context, String action, Uri data, Bundle extras, String packageName,
            String receiverPermission, BroadcastReceiver resultReceiver) {
        Intent outIntent = new Intent(action);
        PackageManager pm = context.getPackageManager();
        List<ResolveInfo> receivers = pm.queryBroadcastReceivers(outIntent, 0);
        if (receivers != null)
            for (ResolveInfo receiver : receivers) {
                if ((packageName != null) && !packageName.equals(receiver.activityInfo.applicationInfo.packageName))
                    continue;
                ComponentName cn = new ComponentName(receiver.activityInfo.applicationInfo.packageName,
                        receiver.activityInfo.name);
                outIntent = new Intent(action);
                if (data != null)
                    outIntent.setData(data);
                if (extras != null)
                    outIntent.putExtras(extras);
                outIntent.setComponent(cn);
                context.sendOrderedBroadcast(outIntent,
                        receiverPermission,
                        resultReceiver,
                        null, // scheduler,
                        RESULT_INTERNAL_ERROR, // initialCode,
                        null, // initialData,
                        null);
            }
    }

    private static String formatTraffError(int code) {
        if ((code < 0) || (code >= ERROR_STRINGS.length))
            return String.format("unknown (%d)", code);
        else
            return ERROR_STRINGS[code];
    }
}