From 83162821c7a721382791acddf5be136d1130f8b1 Mon Sep 17 00:00:00 2001
From: Justin Ghan <justinghan@google.com>
Date: Tue, 4 Oct 2022 12:17:28 -0700
Subject: [PATCH] Fix whitespace removal bug

The implementation of whitespace removal in
performHandwritingDeleteGesture had a bug causing an
IndexOutOfBoundsException when the whitespace was at the start or end of
the text.

This also fixes the whitespace removal code in
performHandwritingJoinOrSplitGesture to properly handle supplementary
characters.

Bug: 243983058
Test: atest android.widget.cts.TextViewHandwritingGestureTest
Change-Id: I3cfef91d05d5619668ccfc0d1259b6b1fd96bed9
---
 core/java/android/widget/TextView.java | 27 +++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/core/java/android/widget/TextView.java b/core/java/android/widget/TextView.java
index da786f3a95be7..b339d76938afe 100644
--- a/core/java/android/widget/TextView.java
+++ b/core/java/android/widget/TextView.java
@@ -9358,10 +9358,11 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                 // - The deleted text is at the end of the text
                 //     e.g. "one [deleted]" -> "one |" -> "one|"
                 // (The pipe | indicates the cursor position.)
-                while (start > 0 && TextUtils.isWhitespaceExceptNewline(codePointBeforeStart)) {
+                do {
                     start -= Character.charCount(codePointBeforeStart);
+                    if (start == 0) break;
                     codePointBeforeStart = Character.codePointBefore(mText, start);
-                }
+                } while (TextUtils.isWhitespaceExceptNewline(codePointBeforeStart));
             } else if (TextUtils.isWhitespaceExceptNewline(codePointAtEnd)
                     && (TextUtils.isWhitespace(codePointBeforeStart)
                             || TextUtils.isPunctuation(codePointBeforeStart))) {
@@ -9373,11 +9374,11 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
                 // - The deleted text is at the start of the text
                 //     e.g. "[deleted] two" -> "| two" -> "|two"
                 // (The pipe | indicates the cursor position.)
-                while (end < mText.length()
-                        && TextUtils.isWhitespaceExceptNewline(codePointAtEnd)) {
+                do {
                     end += Character.charCount(codePointAtEnd);
+                    if (end == mText.length()) break;
                     codePointAtEnd = Character.codePointAt(mText, end);
-                }
+                } while (TextUtils.isWhitespaceExceptNewline(codePointAtEnd));
             }
         }
 
@@ -9487,11 +9488,19 @@ public class TextView extends View implements ViewTreeObserver.OnPreDrawListener
         }
 
         int endOffset = startOffset;
-        while (startOffset > 0 && Character.isWhitespace(mText.charAt(startOffset - 1))) {
-            startOffset--;
+        while (startOffset > 0) {
+            int codePointBeforeStart = Character.codePointBefore(mText, startOffset);
+            if (!TextUtils.isWhitespace(codePointBeforeStart)) {
+                break;
+            }
+            startOffset -= Character.charCount(codePointBeforeStart);
         }
-        while (endOffset < mText.length() && Character.isWhitespace(mText.charAt(endOffset))) {
-            endOffset++;
+        while (endOffset < mText.length()) {
+            int codePointAtEnd = Character.codePointAt(mText, endOffset);
+            if (!TextUtils.isWhitespace(codePointAtEnd)) {
+                break;
+            }
+            endOffset += Character.charCount(codePointAtEnd);
         }
         if (startOffset < endOffset) {
             getEditableText().delete(startOffset, endOffset);