Core Apps » Bazaar

/*

 * Copyright (C) 2010-2012 Ciaran Gultnieks <ciaran@ciarang.com>

 * Copyright (C) 2011 Henrik Tunedal <tunedal@gmail.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 3

 * of the License, or (at your option) any later version.

 *

 * 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.fdroid.fdroid.net;

import android.content.Context;

import android.os.Build;

import android.content.Intent;

import android.os.Bundle;

import android.support.annotation.NonNull;

import android.support.v4.content.LocalBroadcastManager;

import android.util.Log;

import org.fdroid.fdroid.Hasher;

import org.fdroid.fdroid.Preferences;

import org.fdroid.fdroid.ProgressListener;

import org.fdroid.fdroid.Utils;

import org.fdroid.fdroid.compat.FileCompat;

import org.fdroid.fdroid.data.Apk;

import org.fdroid.fdroid.data.App;

import org.fdroid.fdroid.data.SanitizedFile;

import java.io.File;

import java.io.IOException;

import java.net.URL;

import java.security.NoSuchAlgorithmException;

/**

 * Downloads and verifies (against the Apk.hash) the apk file.

 * If the file has previously been downloaded, it will make use of that

 * instead, without going to the network to download a new one.

 */

public class ApkDownloader implements AsyncDownloader.Listener {

    private static final String TAG = "ApkDownloader";

    public static final String EVENT_APK_DOWNLOAD_COMPLETE = "apkDownloadComplete";

    public static final String EVENT_APK_DOWNLOAD_CANCELLED = "apkDownloadCancelled";

    public static final String EVENT_ERROR = "apkDownloadError";

    public static final String ACTION_STATUS = "apkDownloadStatus";

    public static final String EXTRA_TYPE = "apkDownloadStatusType";

    public static final String EXTRA_URL = "apkDownloadUrl";

    public static final int ERROR_HASH_MISMATCH = 101;

    public static final int ERROR_DOWNLOAD_FAILED = 102;

    private static final String EVENT_SOURCE_ID = "sourceId";

    private static long downloadIdCounter = 0;

    /**

     * Used as a key to pass data through with an error event, explaining the type of event.

     */

    public static final String EVENT_DATA_ERROR_TYPE = "apkDownloadErrorType";

    @NonNull private final App app;

    @NonNull private final Apk curApk;

    @NonNull private final Context context;

    @NonNull private final String repoAddress;

    @NonNull private final SanitizedFile localFile;

    @NonNull private final SanitizedFile potentiallyCachedFile;

    private ProgressListener listener;

    private AsyncDownloader dlWrapper = null;

    private boolean isComplete = false;

    private final long id = ++downloadIdCounter;

    public void setProgressListener(ProgressListener listener) {

        this.listener = listener;

    }

    public void removeProgressListener() {

        setProgressListener(null);

    }

    public ApkDownloader(@NonNull final Context context, @NonNull final App app, @NonNull final Apk apk, @NonNull final String repoAddress) {

        this.context = context;

        this.app = app;

        curApk = apk;

        this.repoAddress = repoAddress;

        localFile = new SanitizedFile(Utils.getApkDownloadDir(context), apk.apkName);

        potentiallyCachedFile = new SanitizedFile(Utils.getApkCacheDir(context), apk.apkName);

    }

    /**

     * The downloaded APK. Valid only when getStatus() has returned STATUS.DONE.

     */

    public SanitizedFile localFile() {

        return localFile;

    }

    /**

     * When stopping/starting downloaders multiple times (on different threads), it can

     * get weird whereby different threads are sending progress events. It is important

     * to be able to see which downloader these progress events are coming from.

     */

    public boolean isEventFromThis(Event event) {

        return event.getData().containsKey(EVENT_SOURCE_ID) && event.getData().getLong(EVENT_SOURCE_ID) == id;

    }

    private Hasher createHasher(File apkFile) {

        Hasher hasher;

        try {

            hasher = new Hasher(curApk.hashType, apkFile);

        } catch (NoSuchAlgorithmException e) {

            Log.e(TAG, "Error verifying hash of cached apk at " + apkFile + ". " +

                    "I don't understand what the " + curApk.hashType + " hash algorithm is :(");

            hasher = null;

        }

        return hasher;

    }

    private boolean hashMatches(@NonNull final File apkFile) {

        if (!apkFile.exists()) {

            return false;

        }

        Hasher hasher = createHasher(apkFile);

        return hasher != null && hasher.match(curApk.hash);

    }

    /**

     * If an existing cached version exists, and matches the hash of the apk we

     * want to download, then we will return true. Otherwise, we return false

     * (and remove the cached file - if it exists and didn't match the correct hash).

     */

    private boolean verifyOrDelete(@NonNull final File apkFile) {

        if (apkFile.exists()) {

            if (hashMatches(apkFile)) {

                Utils.DebugLog(TAG, "Using cached apk at " + apkFile);

                return true;

            }

            Utils.DebugLog(TAG, "Not using cached apk at " + apkFile + "(hash doesn't match, will delete file)");

            delete(apkFile);

        }

        return false;

    }

    private void delete(@NonNull final File file) {

        if (file.exists()) {

            if (!file.delete()) {

                Log.w(TAG, "Could not delete file " + file);

            }

        }

    }

    private void prepareApkFileAndSendCompleteMessage() {

        // Need the apk to be world readable, so that the installer is able to read it.

        // Note that saving it into external storage for the purpose of letting the installer

        // have access is insecure, because apps with permission to write to the external

        // storage can overwrite the app between F-Droid asking for it to be installed and

        // the installer actually installing it.

        FileCompat.setReadable(localFile, true, false);

        isComplete = true;

        sendMessage(EVENT_APK_DOWNLOAD_COMPLETE);

    }

    public boolean isComplete() {

        return this.isComplete;

    }

    /**

     * If the download successfully spins up a new thread to start downloading, then we return

     * true, otherwise false. This is useful, e.g. when we use a cached version, and so don't

     * want to bother with progress dialogs et al.

     */

    public boolean download() {

        // Can we use the cached version?

        if (verifyOrDelete(potentiallyCachedFile)) {

            delete(localFile);

            Utils.copy(potentiallyCachedFile, localFile);

            prepareApkFileAndSendCompleteMessage();

            return false;

        }

        String remoteAddress = Utils.getApkUrl(repoAddress, curApk);

        Utils.DebugLog(TAG, "Downloading apk from " + remoteAddress + " to " + localFile);

        try {

            dlWrapper = DownloaderFactory.createAsync(context, remoteAddress, localFile, app.name + " " + curApk.version, curApk.id, this);

            dlWrapper.download();

            return true;

        } catch (IOException e) {

            onErrorDownloading(e.getLocalizedMessage());

        }

        return false;

    }

    private void sendMessage(String type) {

        sendProgressEvent(new ProgressListener.Event(type));

    }

    private void sendError(int errorType) {

        Bundle data = new Bundle(1);

        data.putInt(EVENT_DATA_ERROR_TYPE, errorType);

        sendProgressEvent(new Event(EVENT_ERROR, data));

    }

    // TODO: Completely remove progress listener, only use broadcasts...

    private void sendProgressEvent(Event event) {

        event.getData().putLong(EVENT_SOURCE_ID, id);

        if (listener != null) {

            listener.onProgress(event);

        }

        Intent intent = new Intent(ACTION_STATUS);

        intent.putExtras(event.getData());

        intent.putExtra(EXTRA_TYPE, event.type);

        intent.putExtra(EXTRA_URL, Utils.getApkUrl(repoAddress, curApk));

        LocalBroadcastManager.getInstance(context).sendBroadcast(intent);

    }

    @Override

    public void onErrorDownloading(String localisedExceptionDetails) {

        Log.e(TAG, "Download failed: " + localisedExceptionDetails);

        sendError(ERROR_DOWNLOAD_FAILED);

        delete(localFile);

    }

    private void cacheIfRequired() {

        if (Preferences.get().shouldCacheApks()) {

            Utils.DebugLog(TAG, "Copying .apk file to cache at " + potentiallyCachedFile.getAbsolutePath());

            Utils.copy(localFile, potentiallyCachedFile);

        }

    }

    @Override

    public void onDownloadComplete() {

        if (!verifyOrDelete(localFile)) {

            sendError(ERROR_HASH_MISMATCH);

            return;

        }

        cacheIfRequired();

        Utils.DebugLog(TAG, "Download finished: " + localFile);

        prepareApkFileAndSendCompleteMessage();

    }

    @Override

    public void onDownloadCancelled() {

        sendMessage(EVENT_APK_DOWNLOAD_CANCELLED);

    }

    @Override

    public void onProgress(Event event) {

        sendProgressEvent(event);

    }

    /**

     * Attempts to cancel the download (if in progress) and also removes the progress

     * listener

     *

     * @param userRequested - true if the user requested the cancel (via button click), otherwise false.

     */

    public void cancel(boolean userRequested) {

        if (dlWrapper != null) {

            dlWrapper.attemptCancel(userRequested);

        }

    }

    public Apk getApk() { return curApk; }

    public int getBytesRead() { return dlWrapper != null ? dlWrapper.getBytesRead() : 0; }

    public int getTotalBytes() { return dlWrapper != null ? dlWrapper.getTotalBytes() : 0; }

}