vfs_tree.h

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/* Copyright (C) 2016 Wildfire Games.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * 'tree' of VFS directories and files
 */

#ifndef INCLUDED_VFS_TREE
#define INCLUDED_VFS_TREE

#include <map>

#include "lib/file/file_system.h"   // CFileInfo
#include "lib/file/common/file_loader.h"    // PIFileLoader
#include "lib/file/common/real_directory.h" // PRealDirectory
#include "lib/file/vfs/vfs_path.h"

class VfsFile
{
public:
    VfsFile(const VfsPath& name, size_t size, time_t mtime, size_t priority, const PIFileLoader& provider);

    const VfsPath& Name() const
    {
        return m_name;
    }

    size_t Size() const
    {
        return m_size;
    }

    time_t MTime() const
    {
        return m_mtime;
    }

    size_t Priority() const
    {
        return m_priority;
    }

    const PIFileLoader& Loader() const
    {
        return m_loader;
    }

private:
    VfsPath m_name;
    size_t m_size;
    time_t m_mtime;

    size_t m_priority;

    PIFileLoader m_loader;
};


class VfsDirectory
{
    /**
     * remove all files with a lower priority than @p file
     * and do the same for all subdirectories recursively.
     * @return true if the directory is empty afterwards
     **/
    bool DeleteTree(const VfsFile& file);

public:
    typedef std::map<VfsPath, VfsFile> VfsFiles;
    typedef std::map<VfsPath, VfsDirectory> VfsSubdirectories;

    VfsDirectory();

    /**
     * remove the given file or subdirectory according to the priority of the
     * passed .DELETED file.
     * CAUTION: Invalidates all previously returned pointers of the file or
     *          subdirectory (and contents) if those have lower priority
     *          than @p file.
     **/
    void DeleteSubtree(const VfsFile& file);

    /**
     * @return address of existing or newly inserted file.
     **/
    VfsFile* AddFile(const VfsFile& file);

    /**
     * @return address of existing or newly inserted subdirectory.
     **/
    VfsDirectory* AddSubdirectory(const VfsPath& name);

    /**
     * remove the given file from the virtual directory (no effect on
     * the physical file). no effect if the file does not exist.
     **/
    void RemoveFile(const VfsPath& name);

    /**
     * @return file with the given name.
     * (note: non-const to allow changes to the file)
     **/
    VfsFile* GetFile(const VfsPath& name);

    /**
     * @return subdirectory with the given name.
     * (note: non-const to allow changes to the subdirectory)
     **/
    VfsDirectory* GetSubdirectory(const VfsPath& name);

    // note: exposing only iterators wouldn't enable callers to reserve space.

    const VfsFiles& Files() const
    {
        return m_files;
    }

    const VfsSubdirectories& Subdirectories() const
    {
        return m_subdirectories;
    }

    /**
     * side effect: the next ShouldPopulate() will return true.
     **/
    void SetAssociatedDirectory(const PRealDirectory& realDirectory);

    const PRealDirectory& AssociatedDirectory() const
    {
        return m_realDirectory;
    }

    /**
     * @return whether this directory should be populated from its
     * AssociatedDirectory(). note that calling this is a promise to
     * do so if true is returned -- the flag is reset immediately.
     **/
    bool ShouldPopulate();

    /**
     * ensure the next ShouldPopulate returns true.
     **/
    void RequestRepopulate();

    /**
     * empty file and subdirectory lists (e.g. when rebuilding VFS).
     * CAUTION: this invalidates all previously returned pointers.
     **/
    void Clear();

private:
    VfsFiles m_files;
    VfsSubdirectories m_subdirectories;

    PRealDirectory m_realDirectory;
    volatile intptr_t m_shouldPopulate; // (cpu_CAS can't be used on bool)
};


/**
 * @return a string containing file attributes (location, size, timestamp) and name.
 **/
extern std::wstring FileDescription(const VfsFile& file);

/**
 * @return a string holding each files' description (one per line).
 **/
extern std::wstring FileDescriptions(const VfsDirectory& directory, size_t indentLevel);

/**
 * append each directory's files' description to the given string.
 **/
void DirectoryDescriptionR(std::wstring& descriptions, const VfsDirectory& directory, size_t indentLevel);

#endif  // #ifndef INCLUDED_VFS_TREE