From bc60116c5bc49211e926f53d611051c579b69662 Mon Sep 17 00:00:00 2001
From: Yohei Yukawa <yukawa@google.com>
Date: Sun, 17 Jun 2018 21:08:20 -0700
Subject: [PATCH] Fix broken language matching logic in TSMS

Checking language similarity with String#startsWith() is fundamentally
broken.  For instance, "fi" (Finnish) can match "fil" (Filipino).

This CL addresses such a broken comparison.

Bug: 110275412
Test: Manually verified that spell checker still works
Change-Id: I8d71760c534627b7707e16eb0fc648989f7692ae
---
 .../server/TextServicesManagerService.java    | 21 +++++++------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/services/core/java/com/android/server/TextServicesManagerService.java b/services/core/java/com/android/server/TextServicesManagerService.java
index d82ca0b8c3c11..32d22ec9fe8d6 100644
--- a/services/core/java/com/android/server/TextServicesManagerService.java
+++ b/services/core/java/com/android/server/TextServicesManagerService.java
@@ -69,6 +69,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Objects;
 import java.util.function.Predicate;
 
 public class TextServicesManagerService extends ITextServicesManager.Stub {
@@ -536,25 +537,17 @@ public class TextServicesManagerService extends ITextServicesManager.Stub {
                 && !allowImplicitlySelectedSubtype) {
             return null;
         }
-        String candidateLocale = null;
-        if (subtypeHashCode == 0) {
-            // Spell checker language settings == "auto"
-            // Use System locale if available in the spell checker
-            candidateLocale = systemLocale.toString();
-        }
         SpellCheckerSubtype candidate = null;
         for (int i = 0; i < sci.getSubtypeCount(); ++i) {
             final SpellCheckerSubtype scs = sci.getSubtypeAt(i);
             if (subtypeHashCode == 0) {
-                final String scsLocale = scs.getLocale();
-                if (candidateLocale.equals(scsLocale)) {
+                final Locale scsLocale = scs.getLocaleObject();
+                if (Objects.equals(scsLocale, systemLocale)) {
                     return scs;
-                } else if (candidate == null) {
-                    if (candidateLocale.length() >= 2 && scsLocale.length() >= 2
-                            && candidateLocale.startsWith(scsLocale)) {
-                        // Fall back to the applicable language
-                        candidate = scs;
-                    }
+                } else if (candidate == null && systemLocale != null && scsLocale != null
+                        && TextUtils.equals(systemLocale.getLanguage(), scsLocale.getLanguage())) {
+                    // Fall back to the applicable language
+                    candidate = scs;
                 }
             } else if (scs.hashCode() == subtypeHashCode) {
                 if (DBG) {