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 dalvik.system;
18 
19 import dalvik.system.ThreadPrioritySetter;
20 
21 import java.util.Objects;
22 import java.util.TimeZone;
23 import java.util.function.Supplier;
24 
25 import libcore.util.NonNull;
26 import libcore.util.Nullable;
27 
28 /**
29  * Provides lifecycle methods and other hooks for an Android runtime "container" to call into the
30  * runtime and core libraries during initialization. For example, from
31  * {@link com.android.internal.os.RuntimeInit}.
32  *
33  * <p>Having a facade class helps to limit the container's knowledge of runtime and core libraries
34  * internal details. All methods assume the container initialization is single threaded.
35  *
36  * @hide
37  */
38 @libcore.api.CorePlatformApi
39 public final class RuntimeHooks {
40 
41     private static Supplier<String> zoneIdSupplier;
42 
43     // BEGIN Android-added: Customize behavior of Thread.setPriority(). http://b/139521784
44     private static volatile ThreadPrioritySetter threadPrioritySetter;
45     // END Android-added: Customize behavior of Thread.setPriority(). http://b/139521784
46 
RuntimeHooks()47     private RuntimeHooks() {
48         // No need to construct an instance. All methods are static.
49     }
50 
51     /**
52      * Sets the {@link Supplier} that is used by {@link TimeZone} to retrieve the current time zone
53      * ID iff the cached default is {@code null}.
54      *
55      * <p>This method also clears the current {@link TimeZone} default ensuring that the supplier
56      * will be used next time {@link TimeZone#getDefault()} is called (unless
57      * {@link TimeZone#setDefault(TimeZone)} is called with a non-null value in the interim).
58      *
59      * <p>Once set the supplier cannot be changed.
60      */
61     @libcore.api.CorePlatformApi
setTimeZoneIdSupplier(Supplier<String> zoneIdSupplier)62     public static void setTimeZoneIdSupplier(Supplier<String> zoneIdSupplier) {
63         if (RuntimeHooks.zoneIdSupplier != null) {
64             throw new UnsupportedOperationException("zoneIdSupplier instance already set");
65         }
66         RuntimeHooks.zoneIdSupplier = Objects.requireNonNull(zoneIdSupplier);
67         TimeZone.setDefault(null);
68     }
69 
70     /**
71      * Returns the {@link Supplier} that should be used to discover the time zone.
72      */
getTimeZoneIdSupplier()73     public static Supplier<String> getTimeZoneIdSupplier() {
74         return RuntimeHooks.zoneIdSupplier;
75     }
76 
77     /**
78      * Sets an {@link Thread.UncaughtExceptionHandler} that will be called before any
79      * returned by {@link Thread#getUncaughtExceptionHandler()}. To allow the standard
80      * handlers to run, this handler should never terminate this process. Any
81      * throwables thrown by the handler will be ignored by
82      * {@link Thread#dispatchUncaughtException(Throwable)}.
83      */
84     @libcore.api.CorePlatformApi
setUncaughtExceptionPreHandler( Thread.UncaughtExceptionHandler uncaughtExceptionHandler)85     public static void setUncaughtExceptionPreHandler(
86             Thread.UncaughtExceptionHandler uncaughtExceptionHandler) {
87         Thread.setUncaughtExceptionPreHandler(uncaughtExceptionHandler);
88     }
89 
90     // BEGIN Android-added: Customize behavior of Thread.setPriority(). http://b/139521784
91     /**
92      * Sets a {@link ThreadPrioritySetter} that will be invoked instead of
93      * the default implementation during {@link Thread.setPriority(int)}.
94      * @hide
95      */
96     @libcore.api.CorePlatformApi
setThreadPrioritySetter(@onNull ThreadPrioritySetter threadPrioritySetter)97     public static void setThreadPrioritySetter(@NonNull ThreadPrioritySetter threadPrioritySetter) {
98         RuntimeHooks.threadPrioritySetter = Objects.requireNonNull(threadPrioritySetter);
99     }
100 
101     /**
102      * Returns the last {@code ThreadPrioritySetter} that has been
103      * {@code #setThreadPrioritySetter(ThreadPrioritySetter) set}, or
104      * null if the setter has not yet been called.
105      * @hide
106      */
getThreadPrioritySetter()107     public static @Nullable ThreadPrioritySetter getThreadPrioritySetter() {
108         return threadPrioritySetter;
109     }
110     // END Android-added: Customize behavior of Thread.setPriority(). http://b/139521784
111 }
112