用于获取变量中的目录空间的命令，类似于 C++ for Linux 中的 statfs 命令

Question

我知道 statfs 在传递给它的缓冲区中返回有关已安装文件系统的信息。我需要一个类似的内置函数来获取将目录路径传递给它的目录空间。有人可以帮我吗？蒂亚！

Answer 1

标准的 C++17 解决方案可能是累积目录和子目录中的文件大小。

例子：

#include <cstdint>
#include <deque>
#include <filesystem>
#include <iostream>
#include <string_view>

int cppmain(std::string_view program, std::deque<std::filesystem::path> dirs) {
    if(dirs.empty()) {
        std::cout << "USAGE: " << program << " <directories...>\n";
        return 1;
    }

    std::error_code ec; // for checking errors
    // Generic end-of-dir iterator:
    std::filesystem::directory_iterator end{};

    std::uintmax_t result = 0; // the sum of all file sizes

    do {
        // get the first directory in the deque
        std::filesystem::path dir = std::move(dirs.front());
        dirs.pop_front();

        // loop over all the directory entries in the directory
        for(std::filesystem::directory_iterator dit(dir, ec);
            dit != end; ++dit) 
        {
            if(dit->is_symlink()) {
                std::cerr << "Skipping symlink " << *dit << '\n';

            } else if(dit->is_directory(ec)) {
                // put the directory in the deque to examine later
                dirs.emplace_back(dit->path());

            } else if(dit->is_regular_file(ec)) {
                // a regular file - add its size to the result
                result += dit->file_size();

            } else {
                // if you want to log files you can't check:
                std::cerr << "Unknown size " << *dit << '\n';
            }
        }
        // loop for as long as there are directories in the deque:
    } while(not dirs.empty());

    std::cout << result << '\n';
    return 0;
}

int main(int argc, char* argv[]) {
    // Put all the arguments (except argv[0]) in
    // "std::deque<std::filesystem::path> dirs":
    return cppmain(argv[0], {argv + 1, argv + argc});
}

statfs(2) 的替换可能类似于以下内容 - 但它没有提供像 statfs() 那么多的细节。

#include <filesystem>
#include <iostream>

int main(int argc, char* argv[]) {
    if(argc != 2) {
        std::cout << "USAGE " << argv[0] << " <directory>\n";
        return 1;
    }

    std::error_code ec;
    std::filesystem::path path(argv[1]);
    std::filesystem::space_info si = std::filesystem::space(path, ec);
    if(ec) {
        std::cerr << "Error: " << path << ": " << ec.message() << '\n';
        return 1;
    }

    std::cout << "capacity : " << si.capacity << '\n'
              << "free     : " << si.free << '\n'
              << "available: " << si.available << '\n';
}