FlaxEngine/Source/Engine/Content/Storage/AssetHeader.h

// Copyright (c) 2012-2023 Wojciech Figat. All rights reserved.

#pragma once

#include "Engine/Core/Types/Guid.h"
#include "Engine/Core/Types/Pair.h"
#include "Engine/Core/Types/String.h"
#if USE_EDITOR
#include "Engine/Core/Collections/Array.h"
#endif
#include "FlaxChunk.h"

/// <summary>
/// Marco that computes chunk flag value from chunk zero-index
/// </summary>
#define GET_CHUNK_FLAG(chunkIndex) (1 << chunkIndex)

typedef uint16 AssetChunksFlag;
#define ALL_ASSET_CHUNKS MAX_uint16

/// <summary>
/// Flax Asset header
/// </summary>
struct FLAXENGINE_API AssetHeader
{
    /// <summary>
    /// Unique asset ID
    /// </summary>
    Guid ID;

    /// <summary>
    /// Asset type name
    /// </summary>
    String TypeName;

    /// <summary>
    /// The asset chunks.
    /// </summary>
    FlaxChunk* Chunks[ASSET_FILE_DATA_CHUNKS];

public:
    /// <summary>
    /// Initializes a new instance of the <see cref="AssetHeader"/> struct.
    /// </summary>
    AssetHeader()
    {
        // Cleanup all data
        ID = Guid::Empty;
        Platform::MemoryClear(Chunks, sizeof(Chunks));
    }

public:
    /// <summary>
    /// Gets the chunks.
    /// </summary>
    /// <param name="output">The output data.</param>
    template<typename AllocationType = HeapAllocation>
    void GetChunks(Array<FlaxChunk*, AllocationType>& output) const
    {
        for (int32 i = 0; i < ASSET_FILE_DATA_CHUNKS; i++)
        {
            if (Chunks[i] != nullptr)
                output.Add(Chunks[i]);
        }
    }

    /// <summary>
    /// Gets the chunks that are loaded.
    /// </summary>
    /// <param name="output">The output data.</param>
    template<typename AllocationType = HeapAllocation>
    void GetLoadedChunks(Array<FlaxChunk*, AllocationType>& output) const
    {
        for (int32 i = 0; i < ASSET_FILE_DATA_CHUNKS; i++)
        {
            if (Chunks[i] != nullptr && Chunks[i]->IsLoaded())
                output.Add(Chunks[i]);
        }
    }

    /// <summary>
    /// Gets the amount of created asset chunks.
    /// </summary>
    /// <returns>Created asset chunks</returns>
    int32 GetChunksCount() const
    {
        int32 result = 0;
        for (int32 i = 0; i < ASSET_FILE_DATA_CHUNKS; i++)
        {
            if (Chunks[i] != nullptr)
                result++;
        }
        return result;
    }

    /// <summary>
    /// Deletes all chunks. Warning! Chunks are managed internally, use with caution!
    /// </summary>
    void DeleteChunks()
    {
        for (int32 i = 0; i < ASSET_FILE_DATA_CHUNKS; i++)
        {
            SAFE_DELETE(Chunks[i]);
        }
    }

    /// <summary>
    /// Unlinks all chunks.
    /// </summary>
    void UnlinkChunks()
    {
        Platform::MemoryClear(Chunks, sizeof(Chunks));
    }

    /// <summary>
    /// Gets string with a human-readable info about that header
    /// </summary>
    /// <returns>Header info string</returns>
    String ToString() const;
};

/// <summary>
/// Flax Asset header data
/// </summary>
struct FLAXENGINE_API AssetInitData
{
    /// <summary>
    /// The asset header.
    /// </summary>
    AssetHeader Header;

    /// <summary>
    /// The serialized asset version
    /// </summary>
    uint32 SerializedVersion = 0;

    /// <summary>
    /// The custom asset data (should be small, for eg. texture description structure).
    /// </summary>
    BytesContainer CustomData;

#if USE_EDITOR
    /// <summary>
    /// The asset metadata information. Stored in a Json format.
    /// </summary>
    BytesContainer Metadata;

    /// <summary>
    /// Asset dependencies list used by the asset for tracking (eg. material functions used by material asset). The pair of asset ID and cached file edit time (for tracking modification).
    /// </summary>
    Array<Pair<Guid, DateTime>> Dependencies;
#endif

public:
    /// <summary>
    /// Gets the hash code.
    /// </summary>
    uint32 GetHashCode() const
    {
        // Note: do not use Metadata/Dependencies because it may not be loaded (it's optional)
        uint32 hashCode = GetHash(Header.ID);
        hashCode = (hashCode * 397) ^ SerializedVersion;
        hashCode = (hashCode * 397) ^ CustomData.Length();
        return hashCode;
    }
};