com.facebook.buck.rules.macros.EnvironmentVariableMacroExpander.java Source code

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Here is the source code for com.facebook.buck.rules.macros.EnvironmentVariableMacroExpander.java

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/*
 * Copyright 2014-present Facebook, Inc.
 *
 * 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.facebook.buck.rules.macros;

import com.facebook.buck.model.BuildTarget;
import com.facebook.buck.model.MacroException;
import com.facebook.buck.rules.BuildRuleResolver;
import com.facebook.buck.rules.CellPathResolver;
import com.facebook.buck.util.environment.Platform;
import com.google.common.collect.ImmutableList;

/**
 * Expands $(env XYZ) to use the appropriate shell expansion for the current platform. It does not
 * expand the value of the environment variable in place. Rather, the intention is for the variable
 * to be interpreted when a shell command is invoked.
 */
public class EnvironmentVariableMacroExpander extends AbstractMacroExpander<String> {

    private final Platform platform;

    public EnvironmentVariableMacroExpander(Platform platform) {
        this.platform = platform;
    }

    @Override
    protected String parse(BuildTarget target, CellPathResolver cellNames, ImmutableList<String> input)
            throws MacroException {
        if (input.size() != 1) {
            throw new MacroException(String.format("expected a single argument: %s", input));
        }
        return input.get(0);
    }

    @Override
    public String expandFrom(BuildTarget target, CellPathResolver cellNames, BuildRuleResolver resolver, String var)
            throws MacroException {
        if (platform == Platform.WINDOWS) {
            if ("pwd".equalsIgnoreCase(var)) {
                var = "cd";
            }
            return "%" + var + "%";
        } else {
            return "${" + var + "}";
        }
    }

}