Automation/app/src/main/java/eu/chainfire/libsuperuser/StreamGobbler.java
2021-02-16 13:42:49 +01:00

106 lines
3.5 KiB
Java

/*
* Copyright (C) 2012-2014 Jorrit "Chainfire" Jongma
*
* 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 eu.chainfire.libsuperuser;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.List;
/**
* Thread utility class continuously reading from an InputStream
*/
public class StreamGobbler extends Thread {
/**
* Line callback interface
*/
public interface OnLineListener {
/**
* <p>Line callback</p>
*
* <p>This callback should process the line as quickly as possible.
* Delays in this callback may pause the native process or even
* result in a deadlock</p>
*
* @param line String that was gobbled
*/
void onLine(String line);
}
private String shell = null;
private BufferedReader reader = null;
private List<String> writer = null;
private OnLineListener listener = null;
/**
* <p>StreamGobbler constructor</p>
*
* <p>We use this class because shell STDOUT and STDERR should be read as quickly as
* possible to prevent a deadlock from occurring, or Process.waitFor() never
* returning (as the buffer is full, pausing the native process)</p>
*
* @param shell Name of the shell
* @param inputStream InputStream to read from
* @param outputList List<String> to write to, or null
*/
public StreamGobbler(String shell, InputStream inputStream, List<String> outputList) {
this.shell = shell;
reader = new BufferedReader(new InputStreamReader(inputStream));
writer = outputList;
}
/**
* <p>StreamGobbler constructor</p>
*
* <p>We use this class because shell STDOUT and STDERR should be read as quickly as
* possible to prevent a deadlock from occurring, or Process.waitFor() never
* returning (as the buffer is full, pausing the native process)</p>
*
* @param shell Name of the shell
* @param inputStream InputStream to read from
* @param onLineListener OnLineListener callback
*/
public StreamGobbler(String shell, InputStream inputStream, OnLineListener onLineListener) {
this.shell = shell;
reader = new BufferedReader(new InputStreamReader(inputStream));
listener = onLineListener;
}
@Override
public void run() {
// keep reading the InputStream until it ends (or an error occurs)
try {
String line;
while ((line = reader.readLine()) != null) {
Debug.logOutput(String.format("[%s] %s", shell, line));
if (writer != null) writer.add(line);
if (listener != null) listener.onLine(line);
}
} catch (IOException e) {
// reader probably closed, expected exit condition
}
// make sure our stream is closed and resources will be freed
try {
reader.close();
} catch (IOException e) {
// read already closed
}
}
}