Adrian Roos | 3150dbf | 2018-03-28 18:06:52 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2018 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 | |
| 17 | package android.testing; |
| 18 | |
| 19 | import android.util.Log; |
| 20 | |
| 21 | import com.android.internal.annotations.VisibleForTesting; |
| 22 | |
| 23 | import org.junit.rules.TestRule; |
| 24 | import org.junit.runner.Description; |
| 25 | import org.junit.runners.model.Statement; |
| 26 | |
| 27 | import java.util.ConcurrentModificationException; |
| 28 | |
| 29 | |
| 30 | /** |
| 31 | * Runs the test such that mocks created in it don't use a dedicated classloader. |
| 32 | * |
| 33 | * This allows mocking package-private methods. |
| 34 | * |
| 35 | * WARNING: This is absolutely incompatible with running tests in parallel! |
| 36 | */ |
| 37 | public class DexmakerShareClassLoaderRule implements TestRule { |
| 38 | |
| 39 | private static final String TAG = "ShareClassloaderRule"; |
| 40 | @VisibleForTesting |
| 41 | static final String DEXMAKER_SHARE_CLASSLOADER_PROPERTY = "dexmaker.share_classloader"; |
| 42 | |
| 43 | private static Thread sOwningThread = null; |
| 44 | |
| 45 | @Override |
| 46 | public Statement apply(Statement base, Description description) { |
| 47 | return apply(base::evaluate).toStatement(); |
| 48 | } |
| 49 | |
| 50 | /** |
| 51 | * Runs the runnable such that mocks created in it don't use a dedicated classloader. |
| 52 | * |
| 53 | * This allows mocking package-private methods. |
| 54 | * |
| 55 | * WARNING: This is absolutely incompatible with running tests in parallel! |
| 56 | */ |
| 57 | public static void runWithDexmakerShareClassLoader(Runnable r) { |
| 58 | apply(r::run).run(); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * Returns a statement that first makes sure that only one thread at the time is modifying |
| 63 | * the property. Then actually sets the property, and runs the statement. |
| 64 | */ |
| 65 | private static <T extends Throwable> ThrowingRunnable<T> apply(ThrowingRunnable<T> r) { |
| 66 | return wrapInMutex(wrapInSetAndClearProperty(r)); |
| 67 | } |
| 68 | |
| 69 | private static <T extends Throwable> ThrowingRunnable<T> wrapInSetAndClearProperty( |
| 70 | ThrowingRunnable<T> r) { |
| 71 | return () -> { |
| 72 | final String previousValue = System.getProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY); |
| 73 | try { |
| 74 | System.setProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY, "true"); |
| 75 | r.run(); |
| 76 | } finally { |
| 77 | if (previousValue != null) { |
| 78 | System.setProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY, previousValue); |
| 79 | } else { |
| 80 | System.clearProperty(DEXMAKER_SHARE_CLASSLOADER_PROPERTY); |
| 81 | } |
| 82 | } |
| 83 | }; |
| 84 | } |
| 85 | |
| 86 | /** |
| 87 | * Runs the given statement, and while doing so prevents other threads from running statements. |
| 88 | */ |
| 89 | private static <T extends Throwable> ThrowingRunnable<T> wrapInMutex(ThrowingRunnable<T> r) { |
| 90 | return () -> { |
| 91 | final boolean isOwner; |
| 92 | synchronized (DexmakerShareClassLoaderRule.class) { |
| 93 | isOwner = (sOwningThread == null); |
| 94 | if (isOwner) { |
| 95 | sOwningThread = Thread.currentThread(); |
| 96 | } else if (sOwningThread != Thread.currentThread()) { |
| 97 | final RuntimeException e = new ConcurrentModificationException( |
| 98 | "Tried to set dexmaker.share_classloader from " + Thread.currentThread() |
| 99 | + ", but was already set from " + sOwningThread); |
| 100 | // Also log in case exception gets swallowed. |
| 101 | Log.e(TAG, e.getMessage(), e); |
| 102 | throw e; |
| 103 | } |
| 104 | } |
| 105 | try { |
| 106 | r.run(); |
| 107 | } finally { |
| 108 | synchronized (DexmakerShareClassLoaderRule.class) { |
| 109 | if (isOwner) { |
| 110 | sOwningThread = null; |
| 111 | } |
| 112 | } |
| 113 | } |
| 114 | }; |
| 115 | } |
| 116 | |
| 117 | private interface ThrowingRunnable<T extends Throwable> { |
| 118 | void run() throws T; |
| 119 | |
| 120 | default Statement toStatement() { |
| 121 | return new Statement() { |
| 122 | @Override |
| 123 | public void evaluate() throws Throwable { |
| 124 | ThrowingRunnable.this.run(); |
| 125 | } |
| 126 | }; |
| 127 | } |
| 128 | } |
| 129 | } |