From 6df1d751f48d45450df1ae98261ccfd68d7b282d Mon Sep 17 00:00:00 2001
From: Yan Yan <evitayan@google.com>
Date: Fri, 13 Sep 2024 19:01:15 -0700
Subject: Expose Handler methods for mainlining VCN

Expose the following three methods as a prerequisite
for moving VCN to mainline.
- #hasMessagesOrCallbacks()
- #removeCallbacksAndEqualMessages(Object)
- #removeEqualMessages(int, Object)

Bug: 366598445
Test: atest CtsOsTestCases:HandlerTest
Flag: android.os.mainline_vcn_platform_api
Change-Id: If16bbcdd5aba7438397f50d82b2ffd1555b2dddf
Merged-In: If16bbcdd5aba7438397f50d82b2ffd1555b2dddf
---
 core/api/module-lib-current.txt    |  6 ++++++
 core/java/android/os/Handler.java  | 30 ++++++++++++++++++++++++++++--
 core/java/android/os/flags.aconfig |  8 ++++++++
 3 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/core/api/module-lib-current.txt b/core/api/module-lib-current.txt
index 24e73352ff33..84f2ab2f0915 100644
--- a/core/api/module-lib-current.txt
+++ b/core/api/module-lib-current.txt
@@ -380,6 +380,12 @@ package android.os {
     method @FlaggedApi("android.crashrecovery.flags.enable_crashrecovery") @NonNull public static java.io.File getDataSystemDeDirectory();
   }
 
+  public class Handler {
+    method @FlaggedApi("android.os.mainline_vcn_platform_api") public final boolean hasMessagesOrCallbacks();
+    method @FlaggedApi("android.os.mainline_vcn_platform_api") public final void removeCallbacksAndEqualMessages(@Nullable Object);
+    method @FlaggedApi("android.os.mainline_vcn_platform_api") public final void removeEqualMessages(int, @Nullable Object);
+  }
+
   public class IpcDataCache<Query, Result> {
     ctor public IpcDataCache(int, @NonNull String, @NonNull String, @NonNull String, @NonNull android.os.IpcDataCache.QueryHandler<Query,Result>);
     method public void disableForCurrentProcess();
diff --git a/core/java/android/os/Handler.java b/core/java/android/os/Handler.java
index 80f39bfbdc21..d0828c384664 100644
--- a/core/java/android/os/Handler.java
+++ b/core/java/android/os/Handler.java
@@ -16,8 +16,10 @@
 
 package android.os;
 
+import android.annotation.FlaggedApi;
 import android.annotation.NonNull;
 import android.annotation.Nullable;
+import android.annotation.SystemApi;
 import android.compat.annotation.UnsupportedAppUsage;
 import android.util.Log;
 import android.util.Printer;
@@ -819,16 +821,25 @@ public class Handler {
     }
 
     /**
+     * WARNING: This API is dangerous because if the implementation
+     * of equals() is broken, it would delete unrelated events. For example,
+     * if object.equals() always returns true, it'd remove all messages.
+     *
+     * For this reason, never expose this API to non-platform code. i.e.
+     * this shouldn't be exposed to SystemApi.PRIVILEGED_APPS.
+     *
      * Remove any pending posts of messages with code 'what' and whose obj is
      * 'object' that are in the message queue.  If <var>object</var> is null,
      * all messages will be removed.
-     * <p>
-     * Similar to {@link #removeMessages(int, Object)} but uses object equality
+     *
+     * <p>Similar to {@link #removeMessages(int, Object)} but uses object equality
      * ({@link Object#equals(Object)}) instead of reference equality (==) in
      * determining whether object is the message's obj'.
      *
      *@hide
      */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    @FlaggedApi(android.os.Flags.FLAG_MAINLINE_VCN_PLATFORM_API)
     public final void removeEqualMessages(int what, @Nullable Object object) {
         mQueue.removeEqualMessages(this, what, disallowNullArgumentIfShared(object));
     }
@@ -843,12 +854,25 @@ public class Handler {
     }
 
     /**
+     * WARNING: This API is dangerous because if the implementation
+     * of equals() is broken, it would delete unrelated events. For example,
+     * if object.equals() always returns true, it'd remove all messages.
+     *
+     * For this reason, never expose this API to non-platform code. i.e.
+     * this shouldn't be exposed to SystemApi.PRIVILEGED_APPS.
+     *
      * Remove any pending posts of callbacks and sent messages whose
      * <var>obj</var> is <var>token</var>.  If <var>token</var> is null,
      * all callbacks and messages will be removed.
      *
+     * <p>Similar to {@link #removeCallbacksAndMessages(Object)} but uses object
+     * equality ({@link Object#equals(Object)}) instead of reference equality (==) in
+     * determining whether object is the message's obj'.
+     *
      *@hide
      */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    @FlaggedApi(android.os.Flags.FLAG_MAINLINE_VCN_PLATFORM_API)
     public final void removeCallbacksAndEqualMessages(@Nullable Object token) {
         mQueue.removeCallbacksAndEqualMessages(this, disallowNullArgumentIfShared(token));
     }
@@ -864,6 +888,8 @@ public class Handler {
      * Return whether there are any messages or callbacks currently scheduled on this handler.
      * @hide
      */
+    @SystemApi(client = SystemApi.Client.MODULE_LIBRARIES)
+    @FlaggedApi(android.os.Flags.FLAG_MAINLINE_VCN_PLATFORM_API)
     public final boolean hasMessagesOrCallbacks() {
         return mQueue.hasMessages(this);
     }
diff --git a/core/java/android/os/flags.aconfig b/core/java/android/os/flags.aconfig
index 11b1b08b787d..941ae892f428 100644
--- a/core/java/android/os/flags.aconfig
+++ b/core/java/android/os/flags.aconfig
@@ -209,3 +209,11 @@ flag {
      description: "Tracing using Perfetto SDK."
      bug: "303199244"
 }
+
+flag {
+     name: "mainline_vcn_platform_api"
+     namespace: "vcn"
+     description: "Expose platform APIs to mainline VCN"
+     is_exported: true
+     bug: "366598445"
+}
-- 
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