Avoid expensive O(n) main-thread operation when adding Photo Sphere.

  Bug: 10747001

Change-Id: I8dcc3c5e7dd12879a927aa82e71bea0c6370ccda

1 files changed, 101 insertions, 0 deletions

diff --git a/src/com/android/camera/data/LocalDataList.java b/src/com/android/camera/data/LocalDataList.java
new file mode 100644
index 000000000..3ccc4de54
--- /dev/null
+++ b/src/com/android/camera/data/LocalDataList.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.camera.data;
+
+import android.net.Uri;
+
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.LinkedList;
+
+/**
+ * Fast access data structure for an ordered LocalData list.
+ */
+public class LocalDataList {
+    /**
+     * We use this as a way to compare a Uri to LocalData instances inside a
+     * LinkedList. A linked list in indexOf does a other.equals(get(i)).
+     */
+    private static class UriWrapper {
+        private final Uri mUri;
+
+        public UriWrapper(Uri uri) {
+            mUri = uri;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (!(o instanceof LocalData)) {
+                return false;
+            }
+            return mUri.equals(((LocalData) o).getContentUri());
+        }
+    }
+
+    private LinkedList<LocalData> mList = new LinkedList<LocalData>();
+    private HashMap<Uri, LocalData> mUriMap = new HashMap<Uri, LocalData>();
+
+    public LocalData get(int index) {
+        return mList.get(index);
+    }
+
+    public LocalData remove(int index) {
+        LocalData removedItem = mList.remove(index);
+        mUriMap.remove(removedItem);
+        return removedItem;
+    }
+
+    public LocalData get(Uri uri) {
+        return mUriMap.get(uri);
+    }
+
+    public void set(int pos, LocalData data) {
+        mList.set(pos, data);
+        mUriMap.put(data.getContentUri(), data);
+    }
+
+    public void add(LocalData data) {
+        mList.add(data);
+        mUriMap.put(data.getContentUri(), data);
+    }
+
+    public void add(int pos, LocalData data) {
+        mList.add(pos, data);
+        mUriMap.put(data.getContentUri(), data);
+    }
+
+    public int size() {
+        return mList.size();
+    }
+
+    public void sort(Comparator<LocalData> comparator) {
+        Collections.sort(mList, comparator);
+    }
+
+    /**
+     * This implementation routes through to LinkedList.indexOf, so performs in
+     * O(n) but has a fast exit path for when the uri is not contained in the
+     * list, and immediately returns -1;
+     */
+    public int indexOf(Uri uri) {
+        if (!mUriMap.containsKey(uri)) {
+            return -1;
+        }
+        return mList.indexOf(new UriWrapper(uri));
+    }
+}