Allow items to be removed from the cache

src/ol/structs/lrucache.js

@@ -116,6 +116,34 @@ ol.structs.LRUCache.prototype.get = function(key) {
 };
 
 
+/**
+ * Remove an entry from the cache.
+ * @param {string} key The entry key.
+ * @return {T} The removed entry.
+ */
+ol.structs.LRUCache.prototype.remove = function(key) {
+  var entry = this.entries_[key];
+  ol.asserts.assert(entry !== undefined, 15); // Tried to get a value for a key that does not exist in the cache
+  if (entry === this.newest_) {
+    this.newest_ = /** @type {ol.LRUCacheEntry} */ (entry.older);
+    if (this.newest_) {
+      this.newest_.newer = null;
+    }
+  } else if (entry === this.oldest_) {
+    this.oldest_ = /** @type {ol.LRUCacheEntry} */ (entry.newer);
+    if (this.oldest_) {
+      this.oldest_.older = null;
+    }
+  } else {
+    entry.newer.older = entry.older;
+    entry.older.newer = entry.newer;
+  }
+  delete this.entries_[key];
+  --this.count_;
+  return entry.value_;
+};
+
+
 /**
  * @return {number} Count.
  */

test/spec/ol/structs/lrucache.test.js

@@ -188,6 +188,66 @@ describe('ol.structs.LRUCache', function() {
     });
   });
 
+  describe('#remove()', function() {
+    it('removes an item from the cache', function() {
+      var cache = new ol.structs.LRUCache();
+      cache.set('oldest', 'oldest');
+      cache.set('oldish', 'oldish');
+      cache.set('newish', 'newish');
+      cache.set('newest', 'newest');
+
+      cache.remove('oldish');
+      expect(cache.getCount()).to.eql(3);
+      expect(cache.getValues()).to.eql(['newest', 'newish', 'oldest']);
+    });
+
+    it('works when removing the oldest item', function() {
+      var cache = new ol.structs.LRUCache();
+      cache.set('oldest', 'oldest');
+      cache.set('oldish', 'oldish');
+      cache.set('newish', 'newish');
+      cache.set('newest', 'newest');
+
+      cache.remove('oldest');
+      expect(cache.getCount()).to.eql(3);
+      expect(cache.peekLastKey()).to.eql('oldish');
+      expect(cache.getValues()).to.eql(['newest', 'newish', 'oldish']);
+    });
+
+    it('works when removing the newest item', function() {
+      var cache = new ol.structs.LRUCache();
+      cache.set('oldest', 'oldest');
+      cache.set('oldish', 'oldish');
+      cache.set('newish', 'newish');
+      cache.set('newest', 'newest');
+
+      cache.remove('newest');
+      expect(cache.getCount()).to.eql(3);
+      expect(cache.peekFirstKey()).to.eql('newish');
+      expect(cache.getValues()).to.eql(['newish', 'oldish', 'oldest']);
+    });
+
+    it('returns the removed item', function() {
+      var cache = new ol.structs.LRUCache();
+      var item = {};
+      cache.set('key', item);
+
+      var returned = cache.remove('key');
+      expect(returned).to.be(item);
+    });
+
+    it('throws if the key does not exist', function() {
+      var cache = new ol.structs.LRUCache();
+      cache.set('foo', 'foo');
+      cache.set('bar', 'bar');
+
+      var call = function() {
+        cache.remove('bam');
+      };
+      expect(call).to.throwException();
+    });
+  });
+
   describe('clearing the cache', function() {
     it('clears the cache', function() {
       fillLRUCache(lruCache);