Merge "Move ICU-related initialization code to I18n module"

2 files changed, 79 insertions, 0 deletions

diff --git a/android_icu4j/api/intra/current.txt b/android_icu4j/api/intra/current.txt
index 399ecae10..15b1a34bc 100644
--- a/android_icu4j/api/intra/current.txt
+++ b/android_icu4j/api/intra/current.txt
@@ -194,6 +194,15 @@ package android.icu.util {
 
 }
 
+package com.android.i18n.system {
+
+  public final class ZygoteHooks {
+    method public static void onBeginPreload();
+    method public static void onEndPreload();
+  }
+
+}
+
 package com.android.i18n.timezone {
 
   public final class TimeZoneDataFiles {
diff --git a/android_icu4j/libcore_bridge/src/java/com/android/i18n/system/ZygoteHooks.java b/android_icu4j/libcore_bridge/src/java/com/android/i18n/system/ZygoteHooks.java
new file mode 100644
index 000000000..26e926e40
--- /dev/null
+++ b/android_icu4j/libcore_bridge/src/java/com/android/i18n/system/ZygoteHooks.java
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * 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.android.i18n.system;
+
+import android.icu.impl.CacheValue;
+import android.icu.text.DateFormatSymbols;
+import android.icu.text.DecimalFormatSymbols;
+import android.icu.util.TimeZone;
+import android.icu.util.ULocale;
+
+/**
+ * Provides hooks for {@link dalvik.system.ZygoteHooks} to call into this class to initialize
+ * in the Zygote.
+ *
+ * @hide
+ */
+@libcore.api.IntraCoreApi
+public final class ZygoteHooks {
+
+    /** All methods are static, no need to instantiate. */
+    private ZygoteHooks() {
+    }
+
+    /**
+     * Called when the Zygote begins preloading classes and data.
+     * It caches some ICU objects before the Zygote forks, and tune some behaviors during preload,
+     * e.g. enabling strong cache for preloaded classes.
+     */
+    @libcore.api.IntraCoreApi
+    public static void onBeginPreload() {
+        // Pin ICU data in memory from this point that would normally be held by soft references.
+        // Without this, any references created immediately below or during class preloading
+        // would be collected when the Zygote GC runs in gcAndFinalize().
+        CacheValue.setStrength(CacheValue.Strength.STRONG);
+
+        // Explicitly exercise code to cache data apps/framework are likely to need.
+        ULocale[] localesToPin = { ULocale.ROOT, ULocale.US, ULocale.getDefault() };
+        for (ULocale uLocale : localesToPin) {
+            new DecimalFormatSymbols(uLocale);
+            new DateFormatSymbols(uLocale);
+        }
+
+        // Framework's LocalLog is used during app start-up. It indirectly uses the current ICU time
+        // zone. Pre-loading the current time zone in ICU improves app startup time. b/150605074
+        TimeZone.getDefault();
+    }
+
+    /**
+     * Called when the Zygote has completed preloading classes and data.
+     */
+    @libcore.api.IntraCoreApi
+    public static void onEndPreload() {
+        // All cache references created by ICU from this point will be soft.
+        CacheValue.setStrength(CacheValue.Strength.SOFT);
+    }
+}