AlicizaX/Client/Packages/com.alicizax.unity.resource/Runtime/Resource/ResourceManager.Services.cs

using System.IO;
using UnityEngine;
using YooAsset;

namespace AlicizaX.Resource.Runtime
{
    internal partial class ResourceManager
    {
        /// <summary>
        /// 远端资源地址查询服务类
        /// </summary>
        private class RemoteServices : IRemoteServices
        {
            private readonly string _defaultHostServer;
            private readonly string _fallbackHostServer;

            public RemoteServices(string defaultHostServer, string fallbackHostServer)
            {
                _defaultHostServer = defaultHostServer;
                _fallbackHostServer = fallbackHostServer;
            }

            string IRemoteServices.GetRemoteMainURL(string fileName)
            {
                return $"{_defaultHostServer}/{fileName}";
            }

            string IRemoteServices.GetRemoteFallbackURL(string fileName)
            {
                return $"{_fallbackHostServer}/{fileName}";
            }
        }

        /// <summary>
        /// 资源文件流加载解密类
        /// </summary>
        private class FileStreamDecryption : IDecryptionServices
        {
            /// <summary>
            /// 同步方式获取解密的资源包对象
            /// 注意：加载流对象在资源包对象释放的时候会自动释放
            /// </summary>
            AssetBundle IDecryptionServices.LoadAssetBundle(DecryptFileInfo fileInfo, out Stream managedStream)
            {
                BundleStream bundleStream = new BundleStream(fileInfo.FileLoadPath, FileMode.Open, FileAccess.Read, FileShare.Read);
                managedStream = bundleStream;
                return AssetBundle.LoadFromStream(bundleStream, fileInfo.FileLoadCRC, GetManagedReadBufferSize());
            }

            /// <summary>
            /// 异步方式获取解密的资源包对象
            /// 注意：加载流对象在资源包对象释放的时候会自动释放
            /// </summary>
            AssetBundleCreateRequest IDecryptionServices.LoadAssetBundleAsync(DecryptFileInfo fileInfo, out Stream managedStream)
            {
                BundleStream bundleStream = new BundleStream(fileInfo.FileLoadPath, FileMode.Open, FileAccess.Read, FileShare.Read);
                managedStream = bundleStream;
                return AssetBundle.LoadFromStreamAsync(bundleStream, fileInfo.FileLoadCRC, GetManagedReadBufferSize());
            }

            public byte[] ReadFileData(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            public string ReadFileText(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            private static uint GetManagedReadBufferSize()
            {
                return 1024;
            }
        }

        /// <summary>
        /// 资源文件偏移加载解密类
        /// </summary>
        private class FileOffsetDecryption : IDecryptionServices
        {
            /// <summary>
            /// 同步方式获取解密的资源包对象
            /// 注意：加载流对象在资源包对象释放的时候会自动释放
            /// </summary>
            AssetBundle IDecryptionServices.LoadAssetBundle(DecryptFileInfo fileInfo, out Stream managedStream)
            {
                managedStream = null;
                return AssetBundle.LoadFromFile(fileInfo.FileLoadPath, fileInfo.FileLoadCRC, GetFileOffset());
            }

            /// <summary>
            /// 异步方式获取解密的资源包对象
            /// 注意：加载流对象在资源包对象释放的时候会自动释放
            /// </summary>
            AssetBundleCreateRequest IDecryptionServices.LoadAssetBundleAsync(DecryptFileInfo fileInfo, out Stream managedStream)
            {
                managedStream = null;
                return AssetBundle.LoadFromFileAsync(fileInfo.FileLoadPath, fileInfo.FileLoadCRC, GetFileOffset());
            }

            public byte[] ReadFileData(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            public string ReadFileText(DecryptFileInfo fileInfo)
            {
                throw new System.NotImplementedException();
            }

            private static ulong GetFileOffset()
            {
                return 32;
            }
        }


        /// <summary>
        /// 资源文件解密流
        /// </summary>
        public class BundleStream : FileStream
        {
            public const byte KEY = 64;

            public BundleStream(string path, FileMode mode, FileAccess access, FileShare share) : base(path, mode, access, share)
            {
            }

            public BundleStream(string path, FileMode mode) : base(path, mode)
            {
            }

            public override int Read(byte[] array, int offset, int count)
            {
                var index = base.Read(array, offset, count);
                for (int i = 0; i < array.Length; i++)
                {
                    array[i] ^= KEY;
                }

                return index;
            }
        }
    }
}