SearchCommandLineTask.java

/*
 * Copyright 2014 Yaroslav Mytkalyk
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.docd.purefm.tasks;

import android.util.Log;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.EOFException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.docd.purefm.commandline.CommandFind;
import com.docd.purefm.file.CommandLineFile;
import com.docd.purefm.file.GenericFile;
import com.docd.purefm.settings.Settings;

import org.apache.commons.io.IOUtils;
import android.support.annotation.NonNull;

final class SearchCommandLineTask extends AbstractSearchTask {

    private static final Pattern DENIED = Pattern.compile("^find:\\s(.+):\\sPermission denied$");

    @NonNull
    private final Settings mSettings;

    @NonNull
    private final List<String> mDenied = new ArrayList<>();

    public SearchCommandLineTask(@NonNull final Settings settings,
                                 @NonNull final GenericFile startDirectory,
                                 @NonNull final SearchTaskListener listener) {
        super(startDirectory, listener);
        mSettings = settings;
    }

    @Override
    @NonNull
    public List<String> getDeniedLocations() {
        return mDenied;
    }

    @Override
    protected Void doInBackground(String... params) {
        final CommandFind command = new CommandFind(mStartDirectory.getAbsolutePath(), params);
        // NOTE this doesn't use Shell because we can't create a new CommandLineFile from
        // CommandOutput because executing readlink (which is done in CommandLineFile constructor)
        // will freeze the whole Shell
        DataOutputStream os = null;
        BufferedReader is = null;
        BufferedReader err = null;
        Process process = null;
        try {
            process = Runtime.getRuntime().exec(mSettings.isSuEnabled() ? "su" : "sh");
            os = new DataOutputStream(process.getOutputStream());
            is = new BufferedReader(new InputStreamReader(process.getInputStream()));
            err = new BufferedReader(new InputStreamReader(process.getErrorStream()));
            os.writeBytes(command.toString());
            os.writeBytes("exit\n");
            os.flush();

            String line;
            try {
                while (!isCancelled() && (line = is.readLine()) != null) {
                    this.publishProgress(CommandLineFile.fromLSL(null, line));
                }
            } catch (EOFException e) {
                //ignore
            }

            try {
                while (!isCancelled() && (line = err.readLine()) != null) {
                    final Matcher denied = DENIED.matcher(line);
                    if (denied.matches()) {
                        this.mDenied.add(denied.group(1));
                    }
                }
            } catch (EOFException e) {
                //ignore
            }
            process.waitFor();
        } catch (Exception e) {
            Log.w("Exception while searching", e.toString());
        } finally {
            IOUtils.closeQuietly(os);
            IOUtils.closeQuietly(is);
            IOUtils.closeQuietly(err);
            if (process != null) {
                try {
                    process.destroy();
                } catch (Exception e) {
                    //ignored
                }
            }
        }
        return null;
    }

}