com.facebook.buck.cli.EnvironmentFilter.java Source code

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Here is the source code for com.facebook.buck.cli.EnvironmentFilter.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.cli;

import com.facebook.buck.util.environment.Platform;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;

import java.util.Locale;
import java.util.Map;

/**
 * Utility class to filter system environment maps.
 */
public class EnvironmentFilter {

    // Always exclude environment variables with these names.
    private static final ImmutableSet<String> ENV_TO_REMOVE = ImmutableSet.of(
            // UUID added to environment by OS X.
            "TERM_SESSION_ID",
            // Build ID passed in from Python.
            "BUCK_BUILD_ID");

    // Utility class, do not instantiate.
    private EnvironmentFilter() {
    }

    /**
     * Given a map (environment variable name: environment variable
     * value) pairs, returns a map without the variables which we should
     * not pass to child processes (buck.py, javac, etc.)
     *
     * Keeping the environment map clean helps us avoid jettisoning the
     * parser cache, as we have to rebuild it any time the environment
     * changes.
     */
    public static ImmutableMap<String, String> filteredEnvironment(ImmutableMap<String, String> environment) {
        ImmutableMap.Builder<String, String> filteredEnvironmentBuilder = ImmutableMap.builder();
        for (Map.Entry<String, String> envEntry : environment.entrySet()) {
            String key = envEntry.getKey();
            if (!ENV_TO_REMOVE.contains(key)) {
                if (Platform.detect() == Platform.WINDOWS) {
                    // Windows environment variables are case insensitive.  While an ImmutableMap will throw
                    // if we get duplicate key, we don't have to worry about this for Windows.
                    filteredEnvironmentBuilder.put(key.toUpperCase(Locale.US), envEntry.getValue());
                } else {
                    filteredEnvironmentBuilder.put(envEntry);
                }
            }
        }
        return filteredEnvironmentBuilder.build();
    }
}