filesystem.posix.cc

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#include "os.h"
#if defined(LICORNEA_OS_LINUX) || defined(LICORNEA_OS_DARWIN)
#include "filesystem.h"
#include "assert.h"
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <stdexcept>
#include <limits.h>
#include <iostream>
#include <deque>
#include <system_error>

namespace tlz {

namespace {
    constexpr std::size_t path_max_length = 1024;
}

std::string filename_parent(const std::string& path_) {
    std::string path(path_);
    if(path.back() == '/') path = path.substr(0, path.length() - 1);
    auto pos = path.find_last_of('/');
    if(pos != std::string::npos) return path.substr(0, pos + 1);
    else if(path != "." && path != ".." && path != "") return ".";
    else throw std::invalid_argument("cannot get parent path of " + path);
}

std::string filename_append(const std::string& a, const std::string& b) {
    if(a.back() == '/') return a + b;
    else return a + "/" + b;
}

std::string get_current_directory() {
    char buffer[path_max_length];
    char* path = getcwd(buffer, path_max_length);
    if(path != nullptr) return std::string(path);
    else throw std::system_error(errno, std::system_category(), "getcwd() failed");
}

bool file_exists(const std::string& filename) {
    struct stat sb;
    return (stat(filename.c_str(), &sb) == 0);
}

bool is_directory(const std::string& filename) {
    struct stat sb;
    int result = stat(filename.c_str(), &sb);
    if(result == 0) return S_ISDIR(sb.st_mode);
    else throw std::system_error(errno, std::system_category(), "stat() failed");
}

bool is_file(const std::string& filename) {
    struct stat sb;
    int result = stat(filename.c_str(), &sb);
    if(result == 0) return S_ISREG(sb.st_mode);
    else throw std::system_error(errno, std::system_category(), "stat() failed");
}

std::size_t file_size(const std::string& filename) {
    struct stat sb;
    int result = stat(filename.c_str(), &sb);
    if(result == 0) return sb.st_size;
    else throw std::system_error(errno, std::system_category(), "stat() failed");
}

void make_directory(const std::string& dirname) {
    // don't fail if *directory* already exists at dirname
    
    int result = mkdir(dirname.c_str(), S_IRWXU | S_IRWXG);
    if(result == 0 || (result == -1 && errno == EEXIST && is_directory(dirname))) return;
    else throw std::system_error(errno, std::system_category(), "mkdir() failed");
}

void make_parent_directories(const std::string& filename) {
    std::deque<std::string> new_dirs;
    
    std::string dir = filename_parent(filename);
    while(! file_exists(dir) && dir != "/") {
        new_dirs.push_front(dir);
        dir = filename_parent(dir);
    }
    for(const std::string& dir : new_dirs) {
        make_directory(dir);
    }
}

void delete_file(const std::string& filename) {
    int result = unlink(filename.c_str());
    if(result != 0) throw std::system_error(errno, std::system_category(), "unlink() failed");
}

}

#endif