From b56ca19206a2aebf08e5fd60be63b126838c0dc1 Mon Sep 17 00:00:00 2001
From: Andrea Torlaschi <runnerway@gmail.com>
Date: Thu, 4 Aug 2016 11:49:26 +0200
Subject: [PATCH] ImportKeys: Use cache for Highlighter

---
 .../ui/adapter/ImportKeysAdapterBinding.java  | 17 ++++++++++++--
 .../keychain/util/LruCache.java               | 22 +++++++++++++++++++
 2 files changed, 37 insertions(+), 2 deletions(-)
 create mode 100644 OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/LruCache.java

diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/adapter/ImportKeysAdapterBinding.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/adapter/ImportKeysAdapterBinding.java
index 26e3e5639..82cb85328 100644
--- a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/adapter/ImportKeysAdapterBinding.java
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/adapter/ImportKeysAdapterBinding.java
@@ -9,6 +9,7 @@ import android.widget.TextView;
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.ui.util.Highlighter;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
+import org.sufficientlysecure.keychain.util.LruCache;
 
 public class ImportKeysAdapterBinding {
 
@@ -25,7 +26,7 @@ public class ImportKeysAdapterBinding {
         if (secret) {
             userId = resources.getString(R.string.secret_key) + " " + userId;
         } else {
-            Highlighter highlighter = new Highlighter(context, query);
+            Highlighter highlighter = getHighlighter(context, query);
             userId = highlighter.highlight(userId);
         }
         textView.setText(userId);
@@ -46,7 +47,7 @@ public class ImportKeysAdapterBinding {
         if (userEmail == null)
             userEmail = "";
 
-        Highlighter highlighter = new Highlighter(context, query);
+        Highlighter highlighter = getHighlighter(context, query);
         textView.setText(highlighter.highlight(userEmail));
 
         if (revokedOrExpired) {
@@ -69,4 +70,16 @@ public class ImportKeysAdapterBinding {
         textView.setText(KeyFormattingUtils.beautifyKeyIdWithPrefix(keyId));
     }
 
+    private static LruCache<String, Highlighter> highlighterCache = new LruCache<>(1);
+
+    private static Highlighter getHighlighter(Context context, String query) {
+        Highlighter highlighter = highlighterCache.get(query);
+        if (highlighter == null) {
+            highlighter = new Highlighter(context, query);
+            highlighterCache.put(query, highlighter);
+        }
+
+        return highlighter;
+    }
+
 }
diff --git a/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/LruCache.java b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/LruCache.java
new file mode 100644
index 000000000..3034a2440
--- /dev/null
+++ b/OpenKeychain/src/main/java/org/sufficientlysecure/keychain/util/LruCache.java
@@ -0,0 +1,22 @@
+package org.sufficientlysecure.keychain.util;
+
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+
+// Source: http://stackoverflow.com/a/1953516
+public class LruCache<A, B> extends LinkedHashMap<A, B> {
+
+    private final int maxEntries;
+
+    public LruCache(final int maxEntries) {
+        super(maxEntries + 1, 1.0f, true);
+        this.maxEntries = maxEntries;
+    }
+
+    @Override
+    protected boolean removeEldestEntry(final Map.Entry<A, B> eldest) {
+        return super.size() > maxEntries;
+    }
+
+}