blob: 19c9bf60c3928e4beb2315c2373831f7fad80459 [file] [log] [blame]
// Copyright 2019 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 com.google.common.base.CharMatcher;
import com.google.common.base.Function;
import com.google.common.collect.Iterables;
import com.google.common.escape.CharEscaper;
import com.google.devtools.build.lib.concurrent.ThreadSafety.Immutable;
import javax.annotation.Nullable;
/**
* Utility class to escape strings for use in param files for gcc or clang.
*
* <p>Gcc and Clang interpret the following characters specially: single quote ('), double quote
* ("), backslash (\), space ( ), tab (\t), carriage return (\r), newline (\n), form feed (\f), and
* vertical tab (\u000B). All can be escaped by prefixing the symbol with a backslash.
*/
@Immutable
public final class GccParamFileEscaper extends CharEscaper {
public static final GccParamFileEscaper INSTANCE = new GccParamFileEscaper();
private static final Function<String, String> AS_FUNCTION = INSTANCE.asFunction();
private static final CharMatcher UNSAFECHAR_MATCHER =
CharMatcher.anyOf("'\"\\ \t\r\n\f\u000B").precomputed();
@Override
public String escape(String string) {
if (string.isEmpty()) {
// Empty string is a special case: needs to be quoted to ensure that it
// gets treated as a separate argument.
return "''";
} else {
return super.escape(string);
}
}
@Override
@Nullable
public char[] escape(char c) {
if (!UNSAFECHAR_MATCHER.matches(c)) {
return null;
} else {
char[] result = new char[2];
result[0] = '\\';
result[1] = c;
return result;
}
}
public static String escapeString(String unescaped) {
return INSTANCE.escape(unescaped);
}
/**
* Transforms the input {@code Iterable} of unescaped strings to an {@code Iterable} of escaped
* ones. The escaping is done lazily.
*/
public static Iterable<String> escapeAll(Iterable<? extends String> unescaped) {
return Iterables.transform(unescaped, AS_FUNCTION);
}
}