vfs.h

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/* Conquer Space
 * Copyright (C) 2021-2025 Conquer Space
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#pragma once
 
#include <map>
#include <memory>
#include <string>
#include <vector>
 
namespace cqsp::asset {
enum FileModes {
    Text = 0,         // Opens in text mode
    Binary = 1 << 0,  // If true, file is opened in binary mode, if false, file is opened in text mode
    Read = 0,
    Write = 1 << 1
};
 
enum class Offset { Beg, End, Cur };
 
class IVirtualFile;
class IVirtualDirectory;
class IVirtualFileSystem;
 
typedef std::shared_ptr<IVirtualFile> IVirtualFilePtr;
typedef std::shared_ptr<IVirtualDirectory> IVirtualDirectoryPtr;
typedef std::shared_ptr<IVirtualFileSystem> IVirtualFileSystemPtr;
 
class IVirtualFileSystem {
 public:
    IVirtualFileSystem() {}
    virtual ~IVirtualFileSystem() {}
 
    virtual bool Initialize() = 0;
    virtual IVirtualFilePtr Open(const std::string& path, FileModes modes = Text) = 0;
 
    virtual void Close(IVirtualFilePtr&) = 0;
 
    virtual IVirtualDirectoryPtr OpenDirectory(const std::string& path) = 0;
 
    virtual bool IsFile(const std::string& path) = 0;
 
    virtual bool IsDirectory(const std::string& path) = 0;
 
    virtual bool Exists(const std::string& path) = 0;
};
 
class IVirtualDirectory {
 public:
    IVirtualDirectory() {}
    virtual ~IVirtualDirectory() {}
 
    virtual uint64_t GetSize() = 0;
 
    virtual const std::string& GetRoot() = 0;
 
    virtual IVirtualFilePtr GetFile(int index, FileModes modes = Text) = 0;
 
    virtual const std::string& GetFilename(int index) = 0;
 
    virtual IVirtualFileSystem* GetFileSystem() = 0;
};
 
class IVirtualFile {
 public:
    IVirtualFile() {}
    virtual ~IVirtualFile() {}
 
    virtual uint64_t Size() = 0;
 
    virtual void Read(uint8_t* buffer, int num_bytes) = 0;
 
    virtual bool Seek(long offset, Offset origin = Offset::Cur) = 0;
 
    virtual uint64_t Tell() = 0;
 
    virtual const std::string& Path() = 0;
 
    virtual IVirtualFileSystem* GetFileSystem() = 0;
};
 
class VirtualMounter {
 public:
    ~VirtualMounter();
    void AddMountPoint(const std::string& path, IVirtualFileSystem* fs);
    IVirtualFilePtr Open(const std::string& path, FileModes mode = FileModes::Text);
 
    IVirtualFilePtr Open(const std::string& mount, const std::string& path, FileModes mode = FileModes::Text);
 
    std::shared_ptr<IVirtualDirectory> OpenDirectory(const std::string& path);
 
    std::shared_ptr<IVirtualDirectory> OpenDirectory(const std::string& mount, const std::string& path);
 
    bool IsFile(const std::string& path);
    bool IsFile(const std::string& mount, const std::string& path);
    bool IsDirectory(const std::string& path);
    bool IsDirectory(const std::string& mount, const std::string& path);
    bool Exists(const std::string& path);
    bool Exists(const std::string& mount, const std::string& path);
 
 private:
    std::map<std::string, IVirtualFileSystem*> mount_points;
};
 
// These functions feel like a hack
 
std::vector<uint8_t> ReadAllFromVFile(IVirtualFile*);
 
std::string ReadAllFromVFileToString(IVirtualFile* file);
 
inline std::string GetFilename(const std::string& path) {
    size_t last = path.find_last_of("/\\");
    if (last == std::string::npos) {
        // It's probably the whole thing
        return path;
    }
    return path.substr(last + 1);
}
 
inline std::string GetParentPath(const std::string& path) {
    size_t last = path.find_last_of("/\\");
 
    if (last == std::string::npos) {
        return "";
    }
    return path.substr(0, last);
}
}  // namespace cqsp::asset