assimp.assimp/include/assimp/IOSystem.hpp

/*
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Open Asset Import Library (assimp)
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Copyright (c) 2006-2019, assimp team



All rights reserved.

Redistribution and use of this software in source and binary forms,
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* Redistributions of source code must retain the above
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  following disclaimer.

* Redistributions in binary form must reproduce the above
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* Neither the name of the assimp team, nor the names of its
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  derived from this software without specific prior
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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*/

/** @file IOSystem.hpp
 *  @brief File system wrapper for C++. Inherit this class to supply
 *  custom file handling logic to the Import library.
*/

#pragma once
#ifndef AI_IOSYSTEM_H_INC
#define AI_IOSYSTEM_H_INC

#ifndef __cplusplus
#   error This header requires C++ to be used. aiFileIO.h is the \
    corresponding C interface.
#endif

#include "types.h"

#ifdef _WIN32
#   include <direct.h>  
#   include <stdlib.h>  
#   include <stdio.h>  
#else
#   include <sys/stat.h>
#   include <sys/types.h>
#   include <unistd.h>
#endif // _WIN32

#include <vector>

namespace Assimp    {

    class IOStream;

// ---------------------------------------------------------------------------
/** @brief CPP-API: Interface to the file system.
 *
 *  Derive an own implementation from this interface to supply custom file handling
 *  to the importer library. If you implement this interface, you also want to
 *  supply a custom implementation for IOStream.
 *
 *  @see Importer::SetIOHandler() 
 */
class ASSIMP_API IOSystem
#ifndef SWIG
    : public Intern::AllocateFromAssimpHeap
#endif
{
public:

    // -------------------------------------------------------------------
    /** @brief Default constructor.
     *
     *  Create an instance of your derived class and assign it to an
     *  #Assimp::Importer instance by calling Importer::SetIOHandler().
     */
    IOSystem() AI_NO_EXCEPT;

    // -------------------------------------------------------------------
    /** @brief Virtual destructor.
     *
     *  It is safe to be called from within DLL Assimp, we're constructed
     *  on Assimp's heap.
     */
    virtual ~IOSystem();

    // -------------------------------------------------------------------
    /** @brief For backward compatibility
     *  @see Exists(const char*)
     */
    AI_FORCE_INLINE bool Exists( const std::string& pFile) const;

    // -------------------------------------------------------------------
    /** @brief Tests for the existence of a file at the given path.
     *
     * @param pFile Path to the file
     * @return true if there is a file with this path, else false.
     */
    virtual bool Exists( const char* pFile) const = 0;

    // -------------------------------------------------------------------
    /** @brief Returns the system specific directory separator
     *  @return System specific directory separator
     */
    virtual char getOsSeparator() const = 0;

    // -------------------------------------------------------------------
    /** @brief Open a new file with a given path.
     *
     *  When the access to the file is finished, call Close() to release
     *  all associated resources (or the virtual dtor of the IOStream).
     *
     *  @param pFile Path to the file
     *  @param pMode Desired file I/O mode. Required are: "wb", "w", "wt",
     *         "rb", "r", "rt".
     *
     *  @return New IOStream interface allowing the lib to access
     *         the underlying file.
     *  @note When implementing this class to provide custom IO handling,
     *  you probably have to supply an own implementation of IOStream as well.
     */
    virtual IOStream* Open(const char* pFile,
        const char* pMode = "rb") = 0;

    // -------------------------------------------------------------------
    /** @brief For backward compatibility
     *  @see Open(const char*, const char*)
     */
    inline IOStream* Open(const std::string& pFile,
        const std::string& pMode = std::string("rb"));

    // -------------------------------------------------------------------
    /** @brief Closes the given file and releases all resources
     *    associated with it.
     *  @param pFile The file instance previously created by Open().
     */
    virtual void Close( IOStream* pFile) = 0;

    // -------------------------------------------------------------------
    /** @brief Compares two paths and check whether the point to
     *         identical files.
     *
     * The dummy implementation of this virtual member performs a
     * case-insensitive comparison of the given strings. The default IO
     * system implementation uses OS mechanisms to convert relative into
     * absolute paths, so the result can be trusted.
     * @param one First file
     * @param second Second file
     * @return true if the paths point to the same file. The file needn't
     *   be existing, however.
     */
    virtual bool ComparePaths (const char* one,
        const char* second) const;

    // -------------------------------------------------------------------
    /** @brief For backward compatibility
     *  @see ComparePaths(const char*, const char*)
     */
    inline bool ComparePaths (const std::string& one,
        const std::string& second) const;

    // -------------------------------------------------------------------
    /** @brief Pushes a new directory onto the directory stack.
     *  @param path Path to push onto the stack.
     *  @return True, when push was successful, false if path is empty.
     */
    virtual bool PushDirectory( const std::string &path );

    // -------------------------------------------------------------------
    /** @brief Returns the top directory from the stack.
     *  @return The directory on the top of the stack.
     *          Returns empty when no directory was pushed to the stack.
     */
    virtual const std::string &CurrentDirectory() const;

    // -------------------------------------------------------------------
    /** @brief Returns the number of directories stored on the stack.
     *  @return The number of directories of the stack.
     */
    virtual size_t StackSize() const;

    // -------------------------------------------------------------------
    /** @brief Pops the top directory from the stack.
     *  @return True, when a directory was on the stack. False if no
     *          directory was on the stack.
     */
    virtual bool PopDirectory();

    // -------------------------------------------------------------------
    /** @brief CReates an new directory at the given path.
     *  @param  path    [in] The path to create.
     *  @return True, when a directory was created. False if the directory
     *           cannot be created.
     */
    virtual bool CreateDirectory( const std::string &path );

    // -------------------------------------------------------------------
    /** @brief Will change the current directory to the given path.
     *  @param path     [in] The path to change to.
     *  @return True, when the directory has changed successfully.
     */
    virtual bool ChangeDirectory( const std::string &path );

    virtual bool DeleteFile( const std::string &file );

private:
    std::vector<std::string> m_pathStack;
};

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
IOSystem::IOSystem() AI_NO_EXCEPT
: m_pathStack() {
    // empty
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
IOSystem::~IOSystem() {
    // empty
}

// ----------------------------------------------------------------------------
// For compatibility, the interface of some functions taking a std::string was
// changed to const char* to avoid crashes between binary incompatible STL
// versions. This code her is inlined,  so it shouldn't cause any problems.
// ----------------------------------------------------------------------------

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
IOStream* IOSystem::Open(const std::string& pFile, const std::string& pMode) {
    // NOTE:
    // For compatibility, interface was changed to const char* to
    // avoid crashes between binary incompatible STL versions
    return Open(pFile.c_str(),pMode.c_str());
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::Exists( const std::string& pFile) const {
    // NOTE:
    // For compatibility, interface was changed to const char* to
    // avoid crashes between binary incompatible STL versions
    return Exists(pFile.c_str());
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::ComparePaths (const std::string& one, const std::string& second) const {
    // NOTE:
    // For compatibility, interface was changed to const char* to
    // avoid crashes between binary incompatible STL versions
    return ComparePaths(one.c_str(),second.c_str());
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::PushDirectory( const std::string &path ) {
    if ( path.empty() ) {
        return false;
    }

    m_pathStack.push_back( path );

    return true;
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
const std::string &IOSystem::CurrentDirectory() const {
    if ( m_pathStack.empty() ) {
        static const std::string Dummy("");
        return Dummy;
    }
    return m_pathStack[ m_pathStack.size()-1 ];
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
size_t IOSystem::StackSize() const {
    return m_pathStack.size();
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::PopDirectory() {
    if ( m_pathStack.empty() ) {
        return false;
    }

    m_pathStack.pop_back();

    return true;
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::CreateDirectory( const std::string &path ) {
    if ( path.empty() ) {
        return false;
    }

#ifdef _WIN32
    return 0 != ::_mkdir( path.c_str() );
#else
    return 0 != ::mkdir( path.c_str(), 0777 );
#endif // _WIN32
}

// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::ChangeDirectory( const std::string &path ) {
    if ( path.empty() ) {
        return false;
    }

#ifdef _WIN32
    return 0 != ::_chdir( path.c_str() );
#else
    return 0 != ::chdir( path.c_str() );
#endif // _WIN32
}


// ----------------------------------------------------------------------------
AI_FORCE_INLINE
bool IOSystem::DeleteFile( const std::string &file ) {
    if ( file.empty() ) {
        return false;
    }
    const int retCode( ::remove( file.c_str() ) );
    return ( 0 == retCode );
}
} //!ns Assimp

#endif //AI_IOSYSTEM_H_INC