// Copyright 2016 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.windows;
import java.io.PrintStream;
import java.nio.charset.Charset;
import java.nio.file.Paths;
import java.util.HashMap;
import java.util.Map;
/**
* Mock subprocess to be used for testing Windows process management. Command line usage:
*
* <ul>
* <li><code>I<register><count></code>: Read count bytes to the specified register
* <li><code>O-<string></code>: Write a string to stdout</li>
* <li><code>E-<string></code>: Write a string to stderr</li>
* <li><code>O$<variable></code>: Write an environment variable to stdout</li>
* <li><code>E$<variable></code>: Write an environment variable to stderr</li>
* <li><code>O.</code>: Write the cwd stdout</li>
* <li><code>E.</code>: Write the cwd stderr</li>
* <li><code>O<register></code>: Write the contents of a register to stdout</li>
* <li><code>E<register></code>: Write the contents of a register to stderr</li>
* <li><code>X<exit code%gt;</code>: Exit with the specified exit code</li>
* <li><code>S<seconds></code>: Wait the specified number of seconds</li>
* </ul>
*
* <p>Registers are single characters. Each command line argument is interpreted as a single
* operation. Example:
*
* <code>
* Ia10 Oa Oa Ea E-OVER X42
* </code>
*
* Means: read 10 bytes from stdin, write them back twice to stdout and once to stderr, write
* the string "OVER" to stderr then exit with exit code 42.
*/
public class MockSubprocess {
private static Map<Character, byte[]> registers = new HashMap<>();
private static final Charset UTF8 = Charset.forName("UTF-8");
private static void writeBytes(PrintStream stream, String arg) throws Exception {
byte[] buf;
switch (arg.charAt(1)) {
case '-':
// Immediate string
buf = arg.substring(2).getBytes(UTF8);
break;
case '$':
// Environment variable
buf = System.getenv(arg.substring(2)).getBytes(UTF8);
break;
case '.':
buf = Paths.get(".").toAbsolutePath().normalize().toString().getBytes(UTF8);
break;
default:
buf = registers.get(arg.charAt(1));
break;
}
stream.write(buf, 0, buf.length);
}
public static void main(String[] args) throws Exception {
for (String arg : args) {
switch (arg.charAt(0)) {
case 'I':
char register = arg.charAt(1);
int length = Integer.parseInt(arg.substring(2));
byte[] buf = new byte[length];
registers.put(register, buf);
System.in.read(buf, 0, length);
break;
case 'E':
writeBytes(System.err, arg);
break;
case 'O':
writeBytes(System.out, arg);
break;
case 'W':
try {
Thread.sleep(Integer.parseInt(arg.substring(1)) * 1000);
} catch (InterruptedException e) {
// This is good enough for a mock process
throw new IllegalStateException(e);
}
break;
case 'X':
System.exit(Integer.parseInt(arg.substring(1)));
}
}
}
}