From 53d1f0707323428edf9ec00da4ca98eeb1b5c092 Mon Sep 17 00:00:00 2001
From: vandwalle <vandwalle@google.com>
Date: Wed, 10 Dec 2014 13:25:47 -0800
Subject: [PATCH] make sure wificonfiguration scan cache doesnt grow unbounded
 Bug:18703749

Change-Id: I8e35d602a80b341668d9607db2da3ca6fdb970ae
---
 .../android/net/wifi/WifiConfiguration.java   | 36 +++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/wifi/java/android/net/wifi/WifiConfiguration.java b/wifi/java/android/net/wifi/WifiConfiguration.java
index 0457dda4732af..12902bd55b2c8 100644
--- a/wifi/java/android/net/wifi/WifiConfiguration.java
+++ b/wifi/java/android/net/wifi/WifiConfiguration.java
@@ -927,6 +927,42 @@ public class WifiConfiguration implements Parcelable {
         }
     }
 
+    /** @hide
+     *  trim the scan Result Cache
+     * @param: number of entries to keep in the cache
+     */
+    public void trimScanResultsCache(int num) {
+        if (this.scanResultCache == null) {
+            return;
+        }
+        int currenSize = this.scanResultCache.size();
+        if (currenSize <= num) {
+            return; // Nothing to trim
+        }
+        ArrayList<ScanResult> list = new ArrayList<ScanResult>(this.scanResultCache.values());
+        if (list.size() != 0) {
+            // Sort by descending timestamp
+            Collections.sort(list, new Comparator() {
+                public int compare(Object o1, Object o2) {
+                    ScanResult a = (ScanResult)o1;
+                    ScanResult b = (ScanResult)o2;
+                    if (a.seen > b.seen) {
+                        return 1;
+                    }
+                    if (a.seen < b.seen) {
+                        return -1;
+                    }
+                    return a.BSSID.compareTo(b.BSSID);
+                }
+            });
+        }
+        for (int i = 0; i < currenSize - num ; i++) {
+            // Remove oldest results from scan cache
+            ScanResult result = list.get(i);
+            this.scanResultCache.remove(result.BSSID);
+        }
+    }
+
     /* @hide */
     private ArrayList<ScanResult> sortScanResults() {
         ArrayList<ScanResult> list = new ArrayList<ScanResult>(this.scanResultCache.values());