/*
* Copyright (c) 2023 Vaughn Nugent
*
* Library: VNLib
* Package: ObjectCacheServer
* File: CacheSystemUtil.cs
*
* CacheSystemUtil.cs is part of ObjectCacheServer which is part of the larger
* VNLib collection of libraries and utilities.
*
* ObjectCacheServer is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* ObjectCacheServer is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see https://www.gnu.org/licenses/.
*/
using System;
using System.IO;
using System.Text.Json;
using VNLib.Utils.Resources;
using VNLib.Plugins;
using VNLib.Plugins.Extensions.Loading;
using VNLib.Utils.Extensions;
namespace VNLib.Data.Caching.ObjectCache.Server.Cache
{
internal static class CacheSystemUtil
{
const string PERSISTANT_ASM_CONFIF_KEY = "persistant_cache_asm";
const string USER_CACHE_ASM_CONFIG_KEY = "custom_cache_impl_asm";
const string INITIALIZE_METHOD_NAME = "OnInitializeForBucket";
const string LOAD_METHOD_NAME = "OnRuntimeLoad";
///
/// Loads the implementation (dynamic or default) into the process
/// and initializes it and it's backing store.
///
///
/// The configuration object that contains loading variables
/// The heap for memory cache table to allocate buffers from
/// The cache configuration object
/// The loaded implementation
///
public static IBlobCacheTable LoadMemoryCacheSystem(this PluginBase plugin, IConfigScope config, ICacheMemoryManagerFactory heap, CacheMemoryConfiguration cacheConf)
{
#pragma warning disable CA2000 // Dispose objects before losing scope
//First, try to load persitant cache store
IPersistantCacheStore? pCManager = GetPersistantStore(plugin, config);
#pragma warning restore CA2000 // Dispose objects before losing scope
IBlobCacheTable table;
//See if the user defined a custom cache table implementation
if (config.TryGetValue(USER_CACHE_ASM_CONFIG_KEY, out JsonElement customEl))
{
string asmName = customEl.GetString() ?? throw new FileNotFoundException("User defined a custom blob cache assembly but the file name was null");
//Return the runtime loaded table
table = plugin.CreateServiceExternal(asmName);
//Try to get the load method and pass the persistant cache instance
ManagedLibrary.TryGetMethod>(table, LOAD_METHOD_NAME)?.Invoke(plugin, pCManager);
}
else
{
//Default type
table = new BlobCacheTable(cacheConf.BucketCount, cacheConf.MaxCacheEntries, heap, pCManager);
}
if(pCManager != null)
{
//Initialize the subsystem from the cache table
InitializeSubsystem(pCManager, table);
}
return table;
}
private static void InitializeSubsystem(IPersistantCacheStore store, IBlobCacheTable table)
{
//Try to get the Initialize method
Action? initMethod = ManagedLibrary.TryGetMethod>(store, INITIALIZE_METHOD_NAME);
if(initMethod != null)
{
//Itterate all buckets
table.ForEach(bucket => initMethod(bucket.Id));
}
}
private static IPersistantCacheStore? GetPersistantStore(PluginBase plugin, IConfigScope config)
{
//Get the persistant assembly
if (!config.TryGetValue(PERSISTANT_ASM_CONFIF_KEY, out JsonElement asmEl))
{
return null;
}
string? asmName = asmEl.GetString();
if (string.IsNullOrWhiteSpace(asmName))
{
return null;
}
//Return the
return plugin.CreateServiceExternal(asmName);
}
}
}