From 7e821f0539147b9e8959c4d5c5e39304a4946be0 Mon Sep 17 00:00:00 2001
From: Qi Wang <zakwang@google.com>
Date: Thu, 18 Mar 2021 15:57:46 +0800
Subject: [PATCH] Fix the SuggestionSpan overwrite logic.

Previously, the SpellChecker use the start and end positions as the key
to maintain the SuggestionSpan cache.

However, the actual start/end position of the SuggestionSpan may changes
when the text is changed. Hence we may not be able to find the
corresponding SuggestonSpan for a new suggestion with the changed
start/end positions.

In this fix, we deprecated the cache and use Spanned#getSpans to find
overlapped spans instead.

Change-Id: I1e732f335ad745d85a7620e3ced6858551f18232

Fix: 182982338

Test: atest CtsInputMethodTestCases:SpellCheckerTest
Change-Id: I327e5163499cfc978ff8480664a7e728b6ea7249
---
 core/java/android/widget/SpellChecker.java | 58 ++++++++++++----------
 1 file changed, 31 insertions(+), 27 deletions(-)

diff --git a/core/java/android/widget/SpellChecker.java b/core/java/android/widget/SpellChecker.java
index a63305e55e538..287c18275a96b 100644
--- a/core/java/android/widget/SpellChecker.java
+++ b/core/java/android/widget/SpellChecker.java
@@ -20,12 +20,10 @@ import android.annotation.Nullable;
 import android.text.Editable;
 import android.text.Selection;
 import android.text.Spanned;
-import android.text.TextUtils;
 import android.text.method.WordIterator;
 import android.text.style.SpellCheckSpan;
 import android.text.style.SuggestionSpan;
 import android.util.Log;
-import android.util.LruCache;
 import android.util.Range;
 import android.view.textservice.SentenceSuggestionsInfo;
 import android.view.textservice.SpellCheckerSession;
@@ -98,10 +96,6 @@ public class SpellChecker implements SpellCheckerSessionListener {
 
     private Runnable mSpellRunnable;
 
-    private static final int SUGGESTION_SPAN_CACHE_SIZE = 10;
-    private final LruCache<Long, SuggestionSpan> mSuggestionSpanCache =
-            new LruCache<Long, SuggestionSpan>(SUGGESTION_SPAN_CACHE_SIZE);
-
     public SpellChecker(TextView textView) {
         mTextView = textView;
 
@@ -144,7 +138,6 @@ public class SpellChecker implements SpellCheckerSessionListener {
 
         // Remove existing misspelled SuggestionSpans
         mTextView.removeMisspelledSpans((Editable) mTextView.getText());
-        mSuggestionSpanCache.evictAll();
     }
 
     private void setLocale(Locale locale) {
@@ -410,16 +403,7 @@ public class SpellChecker implements SpellCheckerSessionListener {
                     }
                     if (spellCheckSpanStart >= 0 && spellCheckSpanEnd > spellCheckSpanStart
                             && end > start) {
-                        final Long key = Long.valueOf(TextUtils.packRangeInLong(start, end));
-                        final SuggestionSpan tempSuggestionSpan = mSuggestionSpanCache.get(key);
-                        if (tempSuggestionSpan != null) {
-                            if (DBG) {
-                                Log.i(TAG, "Remove existing misspelled span. "
-                                        + editable.subSequence(start, end));
-                            }
-                            editable.removeSpan(tempSuggestionSpan);
-                            mSuggestionSpanCache.remove(key);
-                        }
+                        removeErrorSuggestionSpan(editable, start, end, RemoveReason.OBSOLETE);
                     }
                 }
                 return spellCheckSpan;
@@ -428,6 +412,35 @@ public class SpellChecker implements SpellCheckerSessionListener {
         return null;
     }
 
+    private enum RemoveReason {
+        /**
+         * Indicates the previous SuggestionSpan is replaced by a new SuggestionSpan.
+         */
+        REPLACE,
+        /**
+         * Indicates the previous SuggestionSpan is removed because corresponding text is
+         * considered as valid words now.
+         */
+        OBSOLETE,
+    }
+
+    private static void removeErrorSuggestionSpan(
+            Editable editable, int start, int end, RemoveReason reason) {
+        SuggestionSpan[] spans = editable.getSpans(start, end, SuggestionSpan.class);
+        for (SuggestionSpan span : spans) {
+            if (editable.getSpanStart(span) == start
+                    && editable.getSpanEnd(span) == end
+                    && (span.getFlags() & (SuggestionSpan.FLAG_MISSPELLED
+                    | SuggestionSpan.FLAG_GRAMMAR_ERROR)) != 0) {
+                if (DBG) {
+                    Log.i(TAG, "Remove existing misspelled/grammar error span on "
+                            + editable.subSequence(start, end) + ", reason: " + reason);
+                }
+                editable.removeSpan(span);
+            }
+        }
+    }
+
     @Override
     public void onGetSuggestions(SuggestionsInfo[] results) {
         final Editable editable = (Editable) mTextView.getText();
@@ -543,16 +556,7 @@ public class SpellChecker implements SpellCheckerSessionListener {
         }
         SuggestionSpan suggestionSpan =
                 new SuggestionSpan(mTextView.getContext(), suggestions, flags);
-        final Long key = Long.valueOf(TextUtils.packRangeInLong(start, end));
-        final SuggestionSpan tempSuggestionSpan = mSuggestionSpanCache.get(key);
-        if (tempSuggestionSpan != null) {
-            if (DBG) {
-                Log.i(TAG, "Cached span on the same position is cleard. "
-                        + editable.subSequence(start, end));
-            }
-            editable.removeSpan(tempSuggestionSpan);
-        }
-        mSuggestionSpanCache.put(key, suggestionSpan);
+        removeErrorSuggestionSpan(editable, start, end, RemoveReason.REPLACE);
         editable.setSpan(suggestionSpan, start, end, Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
 
         mTextView.invalidateRegion(start, end, false /* No cursor involved */);