From 517eff346f27b6c624e2ef6fd7776e823c226c8d Mon Sep 17 00:00:00 2001
From: Christian Schneppe <christian@pix-art.de>
Date: Thu, 19 Sep 2019 11:44:44 +0200
Subject: warn when using _only_ ambiguous cyrillic

---
 .../messenger/utils/IrregularUnicodeDetector.java  | 36 ++++++++++++++++++++--
 1 file changed, 33 insertions(+), 3 deletions(-)

(limited to 'src')

diff --git a/src/main/java/de/pixart/messenger/utils/IrregularUnicodeDetector.java b/src/main/java/de/pixart/messenger/utils/IrregularUnicodeDetector.java
index bf4013e47..74e3aa6c7 100644
--- a/src/main/java/de/pixart/messenger/utils/IrregularUnicodeDetector.java
+++ b/src/main/java/de/pixart/messenger/utils/IrregularUnicodeDetector.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, Daniel Gultsch All rights reserved.
+ * Copyright (c) 2018-2019, Daniel Gultsch All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
@@ -40,6 +40,8 @@ import android.text.style.ForegroundColorSpan;
 import android.util.LruCache;
 
 import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -57,6 +59,7 @@ public class IrregularUnicodeDetector {
 
     private static final Map<Character.UnicodeBlock, Character.UnicodeBlock> NORMALIZATION_MAP;
     private static final LruCache<Jid, PatternTuple> CACHE = new LruCache<>(4096);
+    private static final List<String> AMBIGUOUS_CYRILLIC = Arrays.asList("а", "г", "е", "ѕ", "і", "q", "о", "р", "с", "у");
 
     static {
         Map<Character.UnicodeBlock, Character.UnicodeBlock> temp = new HashMap<>();
@@ -185,13 +188,40 @@ public class IrregularUnicodeDetector {
     private static Set<String> findIrregularCodePoints(String word) {
         Set<String> codePoints;
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
-            codePoints = eliminateFirstAndGetCodePointsCompat(mapCompat(word));
+            final Map<Character.UnicodeBlock, List<String>> map = mapCompat(word);
+            final Set<String> set = asSet(map);
+            if (containsOnlyAmbiguousCyrillic(set)) {
+                return set;
+            }
+            codePoints = eliminateFirstAndGetCodePointsCompat(map);
         } else {
-            codePoints = eliminateFirstAndGetCodePoints(map(word));
+            final Map<Character.UnicodeScript, List<String>> map = map(word);
+            final Set<String> set = asSet(map);
+            if (containsOnlyAmbiguousCyrillic(set)) {
+                return set;
+            }
+            codePoints = eliminateFirstAndGetCodePoints(map);
         }
         return codePoints;
     }
 
+    private static Set<String> asSet(Map<?, List<String>> map) {
+        final Set<String> flat = new HashSet<>();
+        for (List<String> value : map.values()) {
+            flat.addAll(value);
+        }
+        return flat;
+    }
+    
+    private static boolean containsOnlyAmbiguousCyrillic(Collection<String> codePoints) {
+        for (String codePoint : codePoints) {
+            if (!AMBIGUOUS_CYRILLIC.contains(codePoint)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
     private static PatternTuple find(Jid jid) {
         synchronized (CACHE) {
             PatternTuple pattern = CACHE.get(jid);
-- 
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