From 2e376ce96c580589873d12f0192a0c7265f42ad3 Mon Sep 17 00:00:00 2001
From: Yohei Yukawa <yukawa@google.com>
Date: Wed, 26 Apr 2023 20:59:41 -0700
Subject: [PATCH] Implement InputConnectionWrapper#takeSnapshot()

This is a follow up CL to my previous CL [1], which forgot to
implement

  InputConnectionWrapper#takeSnapshot().

As a result, it has alreays returned null even if the wrapped
InputConnection does implement InputConnection#takeSnapshot().  This
means that InputMethodManager#invalidateInput() had always fallen back
to slow InputMethodManager#restartInput() path if an app returned a
wrapped InputConnection for example.

With this CL, wrapped InputConnection can also start taking advantage
of fast restart-input mechanism unless it's further overridden by the
app developer to return null for some reasons.

 [1]: I8e00dacce5ca915e276fdd8288ffc9167eb01a26
      dae47962355ebca330f8fe57e3aa48f4d20a573a

Test: atest CtsInputMethodTestCases:InputConnectionWrapperTest
Fix: 263677142
Change-Id: I9064a4008d688f2e1188c8d78337f0454c101465
---
 .../inputmethod/InputConnectionWrapper.java   | 28 +++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/core/java/android/view/inputmethod/InputConnectionWrapper.java b/core/java/android/view/inputmethod/InputConnectionWrapper.java
index 8f270f5c5eeb6..62f3c909dd4fe 100644
--- a/core/java/android/view/inputmethod/InputConnectionWrapper.java
+++ b/core/java/android/view/inputmethod/InputConnectionWrapper.java
@@ -412,4 +412,32 @@ public class InputConnectionWrapper implements InputConnection {
     public boolean setImeConsumesInput(boolean imeConsumesInput) {
         return mTarget.setImeConsumesInput(imeConsumesInput);
     }
+
+    /**
+     * Called by the system when it needs to take a snapshot of multiple text-related data in an
+     * atomic manner.
+     *
+     * <p><strong>Editor authors</strong>: Supporting this method is strongly encouraged. Atomically
+     * taken {@link TextSnapshot} is going to be really helpful for the system when optimizing IPCs
+     * in a safe and deterministic manner.  Return {@code null} if an atomically taken
+     * {@link TextSnapshot} is unavailable.  The system continues supporting such a scenario
+     * gracefully.</p>
+     *
+     * <p><strong>IME authors</strong>: Currently IMEs cannot call this method directly and always
+     * receive {@code null} as the result.</p>
+     *
+     * <p>Beware that there is a bug that this method was not overridden in
+     * {@link InputConnectionWrapper}, which ended up always returning {@code null} when gets
+     * called even if the wrapped {@link InputConnection} implements this method.  The bug was
+     * fixed in {@link android.os.Build.VERSION_CODES#UPSIDE_DOWN_CAKE}.</p>
+     *
+     * @return {@code null} if {@link TextSnapshot} is unavailable and/or this API is called from
+     *         IMEs. Beware the bug in older devices mentioned above.
+     * @throws NullPointerException if the target is {@code null}.
+     */
+    @Nullable
+    @Override
+    public TextSnapshot takeSnapshot() {
+        return mTarget.takeSnapshot();
+    }
 }