com.google.devtools.build.lib.skyframe.ActionEnvironmentFunction.java Source code

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Here is the source code for com.google.devtools.build.lib.skyframe.ActionEnvironmentFunction.java

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// Copyright 2017 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.skyframe;

import com.google.common.collect.ImmutableList;
import com.google.devtools.build.skyframe.SkyFunction;
import com.google.devtools.build.skyframe.SkyKey;
import com.google.devtools.build.skyframe.SkyValue;
import java.util.Collections;
import java.util.LinkedHashMap;
import java.util.Map;
import javax.annotation.Nullable;

/**
 * Skyframe function that provides the effective value for a client environment variable. This will
 * either be the value coming from the default client environment, or the value coming from the
 * --action_env flag, if the variable's value is explicitly set.
 */
public final class ActionEnvironmentFunction implements SkyFunction {

    @Nullable
    @Override
    public String extractTag(SkyKey skyKey) {
        return null;
    }

    @Nullable
    @Override
    public SkyValue compute(SkyKey skyKey, Environment env) throws InterruptedException {
        Map<String, String> actionEnv = PrecomputedValue.ACTION_ENV.get(env);
        String key = (String) skyKey.argument();
        if (actionEnv.containsKey(key) && actionEnv.get(key) != null) {
            return new ClientEnvironmentValue(actionEnv.get(key));
        }
        return env.getValue(SkyKey.create(SkyFunctions.CLIENT_ENVIRONMENT_VARIABLE, key));
    }

    /** @return the SkyKey to invoke this function for the environment variable {@code variable}. */
    public static SkyKey key(String variable) {
        return SkyKey.create(SkyFunctions.ACTION_ENVIRONMENT_VARIABLE, variable);
    }

    /**
     * Returns a map of environment variable key => values, getting them from Skyframe. Returns null
     * if and only if some dependencies from Skyframe still need to be resolved.
     */
    public static Map<String, String> getEnvironmentView(Environment env, Iterable<String> keys)
            throws InterruptedException {
        ImmutableList.Builder<SkyKey> skyframeKeysBuilder = ImmutableList.builder();
        for (String key : keys) {
            skyframeKeysBuilder.add(key(key));
        }
        ImmutableList<SkyKey> skyframeKeys = skyframeKeysBuilder.build();
        Map<SkyKey, SkyValue> values = env.getValues(skyframeKeys);
        if (env.valuesMissing()) {
            return null;
        }
        // To return the initial order and support null values, we use a LinkedHashMap.
        LinkedHashMap<String, String> result = new LinkedHashMap<>();
        for (SkyKey key : skyframeKeys) {
            ClientEnvironmentValue value = (ClientEnvironmentValue) values.get(key);
            result.put(key.argument().toString(), value.getValue());
        }
        return Collections.unmodifiableMap(result);
    }
}