Moves repository caching logic into new CachePolicies.

src/Umbraco.Core/Cache/DefaultRepositoryCachePolicy.cs

@@ -0,0 +1,222 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Umbraco.Core.Models.EntityBase;
+
+namespace Umbraco.Core.Cache
+{
+    /// <summary>
+    /// The default cache policy for retrieving a single entity
+    /// </summary>
+    /// <typeparam name="TEntity"></typeparam>
+    /// <typeparam name="TId"></typeparam>
+    internal class DefaultRepositoryCachePolicy<TEntity, TId> : DisposableObject, IRepositoryCachePolicy<TEntity, TId>
+        where TEntity : class, IAggregateRoot
+    {
+        private readonly RepositoryCachePolicyOptions _options;
+        protected IRuntimeCacheProvider Cache { get; private set; }
+        private Action _action;
+       
+        public DefaultRepositoryCachePolicy(IRuntimeCacheProvider cache, RepositoryCachePolicyOptions options)
+        {
+            _options = options;
+            Cache = cache;
+        }
+
+        public string GetCacheIdKey(object id)
+        {
+            return string.Format("{0}{1}", GetCacheTypeKey(), id);
+        }
+
+        public string GetCacheTypeKey()
+        {
+            return string.Format("uRepo_{0}_", typeof(TEntity).Name);
+        }
+
+        public void CreateOrUpdate(TEntity entity, Action<TEntity> persistMethod)
+        {
+            var cacheKey = GetCacheIdKey(entity.Id);
+
+            try
+            {
+                persistMethod(entity);
+
+                //set the disposal action                
+                SetCacheAction(() => Cache.InsertCacheItem(cacheKey, () => entity));
+
+                ////If there's a GetAll zero count cache, ensure it is cleared
+                //_cache.ClearCacheItem(GetCacheTypeKey());
+            }
+            catch
+            {
+                //if an exception is thrown we need to remove the entry from cache, this is ONLY a work around because of the way
+                // that we cache entities: http://issues.umbraco.org/issue/U4-4259
+                Cache.ClearCacheItem(cacheKey);
+
+                ////If there's a GetAll zero count cache, ensure it is cleared
+                //_cache.ClearCacheItem(GetCacheTypeKey());
+                throw;
+            }
+        }
+
+        public void Remove(TEntity entity, Action<TEntity> persistMethod)
+        {
+            persistMethod(entity);
+
+            //set the disposal action
+            var cacheKey = GetCacheIdKey(entity.Id);
+            SetCacheAction(() => Cache.ClearCacheItem(cacheKey));
+
+            ////If there's a GetAll zero count cache, ensure it is cleared
+            //_cache.ClearCacheItem(GetCacheTypeKey());
+        }
+
+        public TEntity Get(TId id, Func<TId, TEntity> getFromRepo)
+        {
+            var cacheKey = GetCacheIdKey(id);
+            var fromCache = Cache.GetCacheItem<TEntity>(cacheKey);
+            if (fromCache != null)
+                return fromCache;
+            
+            var entity = getFromRepo(id);
+
+            //set the disposal action
+            SetCacheAction(cacheKey, entity);
+
+            return entity;
+        }
+
+        public TEntity Get(TId id)
+        {
+            var cacheKey = GetCacheIdKey(id);
+            return Cache.GetCacheItem<TEntity>(cacheKey);
+        }
+
+        public bool Exists(TId id, Func<TId, bool> getFromRepo)
+        {
+            var cacheKey = GetCacheIdKey(id);
+            var fromCache = Cache.GetCacheItem<TEntity>(cacheKey);
+            return fromCache != null || getFromRepo(id);
+        }
+
+        public virtual TEntity[] GetAll(TId[] ids, Func<TId[], IEnumerable<TEntity>> getFromRepo)            
+        {
+            if (ids.Any())
+            {
+                var entities = ids.Select(Get).ToArray();
+                if (ids.Length.Equals(entities.Length) && entities.Any(x => x == null) == false)
+                    return entities;
+            }
+            else
+            {
+                var allEntities = GetAllFromCache();
+                if (allEntities.Any())
+                {
+                    if (_options.GetAllCacheValidateCount)
+                    {
+                        //Get count of all entities of current type (TEntity) to ensure cached result is correct
+                        var totalCount = _options.PerformCount();
+                        if (allEntities.Length == totalCount)
+                            return allEntities;
+                    }
+                    else
+                    {
+                        return allEntities;
+                    }
+                }
+                else if (_options.GetAllCacheAllowZeroCount)
+                {
+                    //if the repository allows caching a zero count, then check the zero count cache
+                    var zeroCount = Cache.GetCacheItem<TEntity[]>(GetCacheTypeKey());
+                    if (zeroCount != null && zeroCount.Any() == false)
+                    {
+                        //there is a zero count cache so return an empty list
+                        return new TEntity[] {};
+                    }
+                }
+            }
+
+            //we need to do the lookup from the repo
+            var entityCollection = getFromRepo(ids)
+                //ensure we don't include any null refs in the returned collection!
+                .WhereNotNull()
+                .ToArray();
+
+            //set the disposal action
+            SetCacheAction(ids, entityCollection);
+
+            return entityCollection;
+        }
+
+        /// <summary>
+        /// Performs the lookup for all entities of this type from the cache
+        /// </summary>
+        /// <returns></returns>
+        protected virtual TEntity[] GetAllFromCache()
+        {
+            var allEntities = Cache.GetCacheItemsByKeySearch<TEntity>(GetCacheTypeKey())
+                    .WhereNotNull()
+                    .ToArray();
+            return allEntities.Any() ? allEntities : new TEntity[] {};
+        }
+
+        /// <summary>
+        /// The disposal performs the caching
+        /// </summary>
+        protected override void DisposeResources()
+        {
+            if (_action != null)
+            {
+                _action();
+            }
+        }
+
+        /// <summary>
+        /// Sets the action to execute on disposal for a single entity
+        /// </summary>
+        /// <param name="cacheKey"></param>
+        /// <param name="entity"></param>
+        protected virtual void SetCacheAction(string cacheKey, TEntity entity)
+        {
+            SetCacheAction(() => Cache.InsertCacheItem(cacheKey, () => entity));
+        }
+
+        /// <summary>
+        /// Sets the action to execute on disposal for an entity collection
+        /// </summary>
+        /// <param name="ids"></param>
+        /// <param name="entityCollection"></param>
+        protected virtual void SetCacheAction(TId[] ids, TEntity[] entityCollection)
+        {
+            SetCacheAction(() =>
+            {
+                //This option cannot execute if we are looking up specific Ids
+                if (ids.Any() == false && entityCollection.Length == 0 && _options.GetAllCacheAllowZeroCount)
+                {
+                    //there was nothing returned but we want to cache a zero count result so add an TEntity[] to the cache
+                    // to signify that there is a zero count cache
+                    Cache.InsertCacheItem(GetCacheTypeKey(), () => new TEntity[] {});
+                }
+                else
+                {
+                    //This is the default behavior, we'll individually cache each item so that if/when these items are resolved 
+                    // by id, they are returned from the already existing cache.
+                    foreach (var entity in entityCollection.WhereNotNull())
+                    {
+                        var localCopy = entity;
+                        Cache.InsertCacheItem(GetCacheIdKey(entity.Id), () => localCopy);
+                    }
+                }
+            });
+        }
+
+        /// <summary>
+        /// Sets the action to execute on disposal
+        /// </summary>
+        /// <param name="action"></param>
+        protected void SetCacheAction(Action action)
+        {
+            _action = action;
+        }
+    }
+}