com.google.javascript.jscomp.PrebuildAst.java Source code

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Here is the source code for com.google.javascript.jscomp.PrebuildAst.java

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/*
 * Copyright 2017 The Closure Compiler Authors.
 *
 * 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.javascript.jscomp;

import com.google.common.collect.Iterables;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;
import com.google.common.util.concurrent.MoreExecutors;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
 * A helper class to prebuild ASTs from a list of {@link CompilerInput}. Inputs are parsed into ASTs
 * the first time we try to get them. Get them all now using multiple threads, so they'll be parsed
 * in parallel and already available during the rest of the compilation.
 */
class PrebuildAst {
    private final AbstractCompiler compiler;
    private final int numParallelThreads;

    PrebuildAst(AbstractCompiler compiler, int numParalleThreads) {
        this.compiler = compiler;
        this.numParallelThreads = numParalleThreads;
    }

    void prebuild(Iterable<CompilerInput> allInputs) {
        ThreadFactory threadFactory = new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread t = new Thread(null, r, "jscompiler-PrebuildAst", CompilerExecutor.COMPILER_STACK_SIZE);
                t.setDaemon(true); // Do not prevent the JVM from exiting.
                return t;
            }
        };
        ThreadPoolExecutor poolExecutor = new ThreadPoolExecutor(numParallelThreads, numParallelThreads,
                Integer.MAX_VALUE, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>(), threadFactory);
        ListeningExecutorService executorService = MoreExecutors.listeningDecorator(poolExecutor);
        List<ListenableFuture<?>> futureList = new ArrayList<>(Iterables.size(allInputs));
        // TODO(moz): Support canceling all parsing on the first halting error
        for (final CompilerInput input : allInputs) {
            futureList.add(executorService.submit(new Runnable() {
                @Override
                public void run() {
                    input.getAstRoot(compiler);
                }
            }));
        }

        poolExecutor.shutdown();
        try {
            Futures.allAsList(futureList).get();
        } catch (InterruptedException | ExecutionException e) {
            throw new RuntimeException(e);
        }
    }

}