Merge commit '7621e2f8dec938cf48181c8b10afc9b01f444e68' into beta

submodules/DeviceProximity/Sources/DeviceProximityBag.m

@@ -0,0 +1,63 @@
+#import "DeviceProximityBag.h"
+
+@interface DeviceProximityBag () {
+    NSInteger _nextKey;
+    NSMutableArray *_items;
+    NSMutableArray *_itemKeys;
+}
+
+@end
+
+@implementation DeviceProximityBag
+
+- (instancetype)init {
+    self = [super init];
+    if (self != nil) {
+        _items = [[NSMutableArray alloc] init];
+        _itemKeys = [[NSMutableArray alloc] init];
+    }
+    return self;
+}
+
+- (NSInteger)addItem:(id)item {
+    if (item == nil) {
+        return -1;
+    }
+    
+    NSInteger key = _nextKey;
+    [_items addObject:item];
+    [_itemKeys addObject:@(key)];
+    _nextKey++;
+    
+    return key;
+}
+
+- (void)enumerateItems:(void (^)(id))block {
+    if (block) {
+        for (id item in _items) {
+            block(item);
+        }
+    }
+}
+
+- (void)removeItem:(NSInteger)key {
+    NSUInteger index = 0;
+    for (NSNumber *itemKey in _itemKeys) {
+        if ([itemKey integerValue] == key) {
+            [_items removeObjectAtIndex:index];
+            [_itemKeys removeObjectAtIndex:index];
+            break;
+        }
+        index++;
+    }
+}
+
+- (bool)isEmpty {
+    return _items.count == 0;
+}
+
+- (NSArray *)copyItems {
+    return [[NSArray alloc] initWithArray:_items];
+}
+
+@end