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Speeds up reading of zip source files
By default zip files created via URL connection supports caching. However this built-in cache never invalidate and we don't want that since zip file contents might change over time. Earlier attempt to fix this issue killed caching completely which resulted in each individual entry to be independently loaded from the zip archive. That is very inefficient especially for big zip files. This patch replaces earlier workaround with a timestamp controlled caching so we avoid inefficient re-reads. With this CL, since it is no longer I/O bounded highly parallel parsing of AST (8+ threads) is 3x faster while the total time of bundling reduced by 40-50% (for J2CL sample app). The improvement should reflect similarly for other tools (MF, MSS) as well but I didn't measure how much that will be. The chosen default cache size of 1000 has memory impact around 5MB which is negligible (this is because ZipFile is already designed to be cached indefinitely by JDK since that is default behavior for URLs). Memory testing results/methodology could be found here: http://[]/experimental/users/goktug/zipstress/Main.java?l=30-35 ------------- Created by MOE: https://github.com/google/moe MOE_MIGRATED_REVID=232400779
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|---|---|---|
| @@ -0,0 +1,128 @@ | ||
| /* | ||
| * Copyright 2018 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.annotations.GwtIncompatible; | ||
| import com.google.common.cache.CacheBuilder; | ||
| import com.google.common.cache.CacheLoader; | ||
| import com.google.common.cache.LoadingCache; | ||
| import com.google.common.cache.RemovalNotification; | ||
| import com.google.common.io.CharStreams; | ||
| import java.io.BufferedReader; | ||
| import java.io.IOException; | ||
| import java.io.InputStreamReader; | ||
| import java.io.Reader; | ||
| import java.io.Serializable; | ||
| import java.nio.charset.Charset; | ||
| import java.nio.file.Files; | ||
| import java.nio.file.Path; | ||
| import java.nio.file.Paths; | ||
| import java.nio.file.attribute.FileTime; | ||
| import java.util.zip.ZipFile; | ||
|
|
||
| /** | ||
| * A class that abstract entries from zip files via managed caching. | ||
| * | ||
| * <p>Normally zip files created via URL connection cache indefinite by JDK. That's not good since a | ||
| * zip file contents might change over time (e.g. compiler running as a worker). This class provides | ||
| * a timestamp controlled caching which ensures we always read up-to-date zip while avoiding wasting | ||
| * time by re-reading the zip for each entry. | ||
| */ | ||
| @GwtIncompatible("java.util.zip.ZipFile") | ||
| final class ZipEntryReader implements Serializable { | ||
|
|
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| private static final long serialVersionUID = 1L; | ||
|
|
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| private static final int ZIP_CACHE_SIZE = | ||
| Integer.parseInt(System.getProperty("jscomp.zipfile.cachesize", "1000")); | ||
|
|
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| private static final LoadingCache<String, CachedZipFile> zipFileCache = | ||
| CacheBuilder.newBuilder() | ||
| .maximumSize(ZIP_CACHE_SIZE) | ||
| .removalListener( | ||
| (RemovalNotification<String, CachedZipFile> notification) -> { | ||
| try { | ||
| notification.getValue().maybeClose(); | ||
| } catch (IOException e) { | ||
| throw new RuntimeException(e); | ||
| } | ||
| }) | ||
| .build( | ||
| new CacheLoader<String, CachedZipFile>() { | ||
| @Override | ||
| public CachedZipFile load(String key) throws IOException { | ||
| return new CachedZipFile(key); | ||
| } | ||
| }); | ||
|
|
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| private static class CachedZipFile { | ||
| private final Path path; | ||
| private ZipFile zipFile; | ||
| private volatile FileTime lastModified; | ||
|
|
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| private CachedZipFile(String zipName) { | ||
| this.path = Paths.get(zipName); | ||
| } | ||
|
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| private Reader getReader(String entryName, Charset charset) throws IOException { | ||
| refreshIfNeeded(); | ||
| return new InputStreamReader(zipFile.getInputStream(zipFile.getEntry(entryName)), charset); | ||
| } | ||
|
|
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| private void refreshIfNeeded() throws IOException { | ||
| FileTime newLastModified = Files.getLastModifiedTime(path); | ||
| if (newLastModified.equals(lastModified)) { | ||
| return; | ||
| } | ||
|
|
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| synchronized (this) { | ||
| // Since we do double checked locking (newLastModified is checked out of synchronized), we | ||
| // should test the stamp again. | ||
| if (newLastModified.equals(lastModified)) { | ||
| return; | ||
| } | ||
|
|
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| maybeClose(); | ||
| zipFile = new ZipFile(path.toFile()); | ||
| lastModified = newLastModified; | ||
| } | ||
| } | ||
|
|
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| private void maybeClose() throws IOException { | ||
| if (zipFile != null) { | ||
| zipFile.close(); | ||
| } | ||
| } | ||
| } | ||
|
|
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| private final String zipPath; | ||
| private final String entryName; | ||
|
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| public ZipEntryReader(String zipPath, String entryName) { | ||
| this.zipPath = zipPath; | ||
| this.entryName = entryName; | ||
| } | ||
|
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| public Reader getReader(Charset charset) throws IOException { | ||
| CachedZipFile zipFile = zipFileCache.getUnchecked(zipPath); | ||
| return new BufferedReader(zipFile.getReader(entryName, charset)); | ||
| } | ||
|
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| public String read(Charset charset) throws IOException { | ||
| CachedZipFile zipFile = zipFileCache.getUnchecked(zipPath); | ||
| return CharStreams.toString(zipFile.getReader(entryName, charset)); | ||
| } | ||
| } |