/// <summary>
/// Initializes a new System.Data.Services.BaseServiceProvider instance.
/// </summary>
/// <param name="metadata">Metadata for this provider.</param>
/// <param name="dataServiceInstance">data service instance.</param>
protected BaseServiceProvider(MetadataCacheItem metadata, object dataServiceInstance)
{
WebUtil.CheckArgumentNull(metadata, "metadata");
WebUtil.CheckArgumentNull(dataServiceInstance, "dataServiceInstance");
this.metadata = metadata;
this.dataServiceInstance = dataServiceInstance;
}
/// <summary>Adds a new cache item, and returns the item that is put in the cache.</summary>
/// <param name="serviceType">Type of service with metadata being cached.</param>
/// <param name="dataContextInstance">
/// Data context instance being cached, possibly segmenting the cache
/// space for <paramref name="serviceType"/>.
/// </param>
/// <param name="item">Item being added.</param>
/// <returns>The item being put in the cache (possibly an existing one).</returns>
/// <remarks>This method is thread-safe but not re-entrant.</remarks>
internal static MetadataCacheItem AddCacheItem(Type serviceType, object dataContextInstance, MetadataCacheItem item)
{
Debug.Assert(serviceType != null, "serviceType != null");
Debug.Assert(dataContextInstance != null, "dataContextInstance != null");
Debug.Assert(item != null, "item != null");
MetadataCacheKey key = new MetadataCacheKey(serviceType, dataContextInstance as ObjectContext);
MetadataCacheItem result;
cacheLock.EnterWriteLock();
try
{
// If another thread beat the current thread, we return the
// previously created item, which has a higher chance of
// having survived a garbage collection already.
if (!cache.TryGetValue(key, out result))
{
cache.Add(key, item);
result = item;
}
}
finally
{
cacheLock.ExitWriteLock();
}
Debug.Assert(result != null, "result != null -- a null item is never returned.");
Debug.Assert(
result == TryLookup(serviceType, dataContextInstance),
"result == TryLookup(serviceType, dataContextInstance) -- instance from cache is being returned.");
return(result);
}
/// <summary>
/// Initializes a new System.Data.Services.ReflectionServiceProvider instance.
/// </summary>
/// <param name="metadata">Metadata for this provider.</param>
/// <param name="dataServiceInstance">data service instance.</param>
internal ReflectionServiceProvider(MetadataCacheItem metadata, object dataServiceInstance)
: base(metadata, dataServiceInstance)
{
}