// Copyright 2014 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.util;
import static com.google.common.base.StandardSystemProperty.JAVA_IO_TMPDIR;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.CharMatcher;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.devtools.build.lib.shell.Command;
import com.google.devtools.build.lib.vfs.Path;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* Implements OS aware {@link Command} builder. At this point only Linux, Mac
* and Windows XP are supported.
*
*
Builder will also apply heuristic to identify trivial cases where
* unix-like command lines could be automatically converted into the
* Windows-compatible form.
*
*
TODO(bazel-team): (2010) Some of the code here is very similar to the
* {@link com.google.devtools.build.lib.shell.Shell} class. This should be looked at.
*/
public final class CommandBuilder {
private static final ImmutableList SHELLS = ImmutableList.of("/bin/sh", "/bin/bash");
private static final Splitter ARGV_SPLITTER = Splitter.on(CharMatcher.anyOf(" \t"));
private final OS system;
private final List argv = new ArrayList<>();
private final Map env = new HashMap<>();
private File workingDir = null;
private boolean useShell = false;
public CommandBuilder() {
this(OS.getCurrent());
}
@VisibleForTesting
CommandBuilder(OS system) {
this.system = system;
}
public CommandBuilder addArg(String arg) {
Preconditions.checkNotNull(arg, "Argument must not be null");
argv.add(arg);
return this;
}
public CommandBuilder addArgs(Iterable args) {
Preconditions.checkArgument(!Iterables.contains(args, null), "Arguments must not be null");
Iterables.addAll(argv, args);
return this;
}
public CommandBuilder addArgs(String... args) {
return addArgs(Arrays.asList(args));
}
public CommandBuilder addEnv(Map env) {
Preconditions.checkNotNull(env);
this.env.putAll(env);
return this;
}
public CommandBuilder emptyEnv() {
env.clear();
return this;
}
public CommandBuilder setEnv(Map env) {
emptyEnv();
addEnv(env);
return this;
}
public CommandBuilder setWorkingDir(Path path) {
Preconditions.checkNotNull(path);
workingDir = path.getPathFile();
return this;
}
public CommandBuilder useTempDir() {
workingDir = new File(JAVA_IO_TMPDIR.value());
return this;
}
public CommandBuilder useShell(boolean useShell) {
this.useShell = useShell;
return this;
}
private boolean argvStartsWithSh() {
return argv.size() >= 2 && SHELLS.contains(argv.get(0)) && "-c".equals(argv.get(1));
}
private String[] transformArgvForLinux() {
// If command line already starts with "/bin/sh -c", ignore useShell attribute.
if (useShell && !argvStartsWithSh()) {
// c.g.io.base.shell.Shell.shellify() actually concatenates argv into the space-separated
// string here. Not sure why, but we will do the same.
return new String[] { "/bin/sh", "-c", Joiner.on(' ').join(argv) };
}
return argv.toArray(new String[argv.size()]);
}
private String[] transformArgvForWindows() {
List modifiedArgv;
// Heuristic: replace "/bin/sh -c" with something more appropriate for Windows.
if (argvStartsWithSh()) {
useShell = true;
modifiedArgv = Lists.newArrayList(argv.subList(2, argv.size()));
} else {
modifiedArgv = Lists.newArrayList(argv);
}
if (!modifiedArgv.isEmpty()) {
// args can contain whitespace, so figure out the first word
String argv0 = modifiedArgv.get(0);
String command = ARGV_SPLITTER.split(argv0).iterator().next();
// Automatically enable CMD.EXE use if we are executing something else besides "*.exe" file.
if (!command.toLowerCase().endsWith(".exe")) {
useShell = true;
}
} else {
// This is degenerate "/bin/sh -c" case. We ensure that Windows behavior is identical
// to the Linux - call shell that will do nothing.
useShell = true;
}
if (useShell) {
// /S - strip first and last quotes and execute everything else as is.
// /E:ON - enable extended command set.
// /V:ON - enable delayed variable expansion
// /D - ignore AutoRun registry entries.
// /C - execute command. This must be the last option before the command itself.
return new String[] { "CMD.EXE", "/S", "/E:ON", "/V:ON", "/D", "/C",
"\"" + Joiner.on(' ').join(modifiedArgv) + "\"" };
} else {
return modifiedArgv.toArray(new String[argv.size()]);
}
}
public Command build() {
Preconditions.checkState(system != OS.UNKNOWN, "Unidentified operating system");
Preconditions.checkNotNull(workingDir, "Working directory must be set");
Preconditions.checkState(!argv.isEmpty(), "At least one argument is expected");
return new Command(
system == OS.WINDOWS ? transformArgvForWindows() : transformArgvForLinux(),
env, workingDir);
}
}