com.google.devtools.build.lib.runtime.CommandNameCacheImpl.java Source code

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Here is the source code for com.google.devtools.build.lib.runtime.CommandNameCacheImpl.java

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// Copyright 2016 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.runtime;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;
import com.google.devtools.build.lib.flags.CommandNameCache;
import com.google.devtools.build.lib.util.Preconditions;

import java.util.ArrayDeque;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Queue;
import java.util.Set;

class CommandNameCacheImpl implements CommandNameCache {
    private final Map<String, Command> commandMap;
    private final Map<String, ImmutableSet<String>> cache = new HashMap<>();

    CommandNameCacheImpl(Map<String, BlazeCommand> commandMap) {
        // Note: it is important that this map is live, since the commandMap may be altered
        // post-creation.
        this.commandMap = Maps.transformValues(commandMap, new Function<BlazeCommand, Command>() {
            @Override
            public Command apply(BlazeCommand blazeCommand) {
                return blazeCommand.getClass().getAnnotation(Command.class);
            }
        });
    }

    @Override
    public ImmutableSet<String> get(String commandName) {
        ImmutableSet<String> cachedResult = cache.get(commandName);
        if (cachedResult != null) {
            return cachedResult;
        }
        ImmutableSet.Builder<String> builder = ImmutableSet.builder();

        Command command = Preconditions.checkNotNull(commandMap.get(commandName), commandName);
        Set<Command> visited = new HashSet<>();
        visited.add(command);
        Queue<Command> queue = new ArrayDeque<>();
        queue.add(command);
        while (!queue.isEmpty()) {
            Command cur = queue.remove();
            builder.add(cur.name());
            for (Class<? extends BlazeCommand> clazz : cur.inherits()) {
                Command parent = clazz.getAnnotation(Command.class);
                if (visited.add(parent)) {
                    queue.add(parent);
                }
            }
        }
        cachedResult = builder.build();
        cache.put(commandName, cachedResult);
        return cachedResult;
    }
}