ParallelPackageParser.java revision e29a5a11529dc7df82911b48b9f95461383cbcc2 
1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License
15 */
16
17package com.android.server.pm;
18
19import android.content.pm.PackageParser;
20import android.os.Process;
21import android.os.Trace;
22import android.util.DisplayMetrics;
23
24import com.android.internal.annotations.VisibleForTesting;
25import com.android.internal.util.ConcurrentUtils;
26
27import java.io.File;
28import java.util.List;
29import java.util.concurrent.ArrayBlockingQueue;
30import java.util.concurrent.BlockingQueue;
31import java.util.concurrent.ExecutorService;
32
33import static android.os.Trace.TRACE_TAG_PACKAGE_MANAGER;
34
35/**
36 * Helper class for parallel parsing of packages using {@link PackageParser}.
37 * <p>Parsing requests are processed by a thread-pool of {@link #MAX_THREADS}.
38 * At any time, at most {@link #QUEUE_CAPACITY} results are kept in RAM</p>
39 */
40class ParallelPackageParser implements AutoCloseable {
41
42    private static final int QUEUE_CAPACITY = 10;
43    private static final int MAX_THREADS = 4;
44
45    private final String[] mSeparateProcesses;
46    private final boolean mOnlyCore;
47    private final DisplayMetrics mMetrics;
48    private volatile String mInterruptedInThread;
49
50    private final BlockingQueue<ParseResult> mQueue = new ArrayBlockingQueue<>(QUEUE_CAPACITY);
51
52    private final ExecutorService mService = ConcurrentUtils.newFixedThreadPool(MAX_THREADS,
53            "package-parsing-thread", Process.THREAD_PRIORITY_FOREGROUND);
54
55    ParallelPackageParser(String[] separateProcesses, boolean onlyCoreApps,
56            DisplayMetrics metrics) {
57        mSeparateProcesses = separateProcesses;
58        mOnlyCore = onlyCoreApps;
59        mMetrics = metrics;
60    }
61
62    static class ParseResult {
63
64        PackageParser.Package pkg; // Parsed package
65        File scanFile; // File that was parsed
66        Throwable throwable; // Set if an error occurs during parsing
67
68        @Override
69        public String toString() {
70            return "ParseResult{" +
71                    "pkg=" + pkg +
72                    ", scanFile=" + scanFile +
73                    ", throwable=" + throwable +
74                    '}';
75        }
76    }
77
78    /**
79     * Take the parsed package from the parsing queue, waiting if necessary until the element
80     * appears in the queue.
81     * @return parsed package
82     */
83    public ParseResult take() {
84        try {
85            if (mInterruptedInThread != null) {
86                throw new InterruptedException("Interrupted in " + mInterruptedInThread);
87            }
88            return mQueue.take();
89        } catch (InterruptedException e) {
90            // We cannot recover from interrupt here
91            Thread.currentThread().interrupt();
92            throw new IllegalStateException(e);
93        }
94    }
95
96    /**
97     * Submits the file for parsing
98     * @param scanFile file to scan
99     * @param parseFlags parse falgs
100     */
101    public void submit(File scanFile, int parseFlags) {
102        mService.submit(() -> {
103            ParseResult pr = new ParseResult();
104            Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "parallel parsePackage [" + scanFile + "]");
105            try {
106                PackageParser pp = new PackageParser();
107                pp.setSeparateProcesses(mSeparateProcesses);
108                pp.setOnlyCoreApps(mOnlyCore);
109                pp.setDisplayMetrics(mMetrics);
110                pr.scanFile = scanFile;
111                pr.pkg = parsePackage(pp, scanFile, parseFlags);
112            } catch (Throwable e) {
113                pr.throwable = e;
114            } finally {
115                Trace.traceEnd(TRACE_TAG_PACKAGE_MANAGER);
116            }
117            try {
118                mQueue.put(pr);
119            } catch (InterruptedException e) {
120                Thread.currentThread().interrupt();
121                // Propagate result to callers of take().
122                // This is helpful to prevent main thread from getting stuck waiting on
123                // ParallelPackageParser to finish in case of interruption
124                mInterruptedInThread = Thread.currentThread().getName();
125            }
126        });
127    }
128
129    @VisibleForTesting
130    protected PackageParser.Package parsePackage(PackageParser packageParser, File scanFile,
131            int parseFlags) throws PackageParser.PackageParserException {
132        return packageParser.parsePackage(scanFile, parseFlags);
133    }
134
135    @Override
136    public void close() {
137        List<Runnable> unfinishedTasks = mService.shutdownNow();
138        if (!unfinishedTasks.isEmpty()) {
139            throw new IllegalStateException("Not all tasks finished before calling close: "
140                    + unfinishedTasks);
141        }
142    }
143}
144