linux-wallpaperengine/src/WallpaperEngine/Assets/CDirectory.cpp

#include <sys/stat.h>

#include "CDirectory.h"
#include "CAssetLoadException.h"

using namespace WallpaperEngine::Assets;

CDirectory::CDirectory (std::string basepath) :
    m_basepath (std::move (basepath))
{
    // ensure the specified path exists
    struct stat buffer;

    if (stat (this->m_basepath.c_str (), &buffer) != 0)
        throw std::runtime_error ("Cannot find " + this->m_basepath + ". This folder is required for wallpaper engine to work");

    if (!S_ISDIR(buffer.st_mode))
        throw std::runtime_error ("Cannot find " + this->m_basepath + ". There's an assets file in it's place");
}

CDirectory::~CDirectory ()
{

}

void* CDirectory::readFile (std::string filename, uint32_t* length)
{
    std::string final = this->m_basepath + filename;

    // first check the cache, if the file is there already just return the data in there
    auto it = this->m_cache.find (final);

    if (it != this->m_cache.end ())
    {
        if (length != nullptr)
            *length = (*it).second.length;

        return (*it).second.address;
    }

    FILE* fp = fopen (final.c_str (), "rb");

    if (fp == nullptr)
        throw CAssetLoadException(filename, "Cannot find file");

    // go to the end, get the position and return to the beginning
    fseek (fp, 0, SEEK_END);
    long size = ftell (fp);
    fseek (fp, 0, SEEK_SET);

    // now read the whole file
    char* contents = new char[size];

    if (fread (contents, size, 1, fp) != 1)
    {
        delete[] contents;
        throw CAssetLoadException (filename, "Unexpected error when reading the file");
    }

    // store it in the cache too
    this->m_cache.insert (std::make_pair <std::string, CFileEntry> (
        std::move (final),
        CFileEntry (contents, size)
    ));

    if (length != nullptr)
        *length = size;

    return contents;
}