FileDirGuard.h

#pragma once
 
#include <xrpl/basics/contract.h>
#include <xrpl/beast/unit_test/suite.h>
 
#include <exception>
#include <filesystem>
#include <fstream>
#include <ostream>
#include <stdexcept>
#include <string>
#include <utility>
 
namespace xrpl::detail {

class DirGuard
{
protected:
    using Path = std::filesystem::path;
 
private:
    Path subDir_;
    bool rmSubDir_{false};
 
protected:
    beast::unit_test::Suite& test_;
 
    auto
    rmDir(Path const& toRm)
    {
        if (is_directory(toRm) && is_empty(toRm))
        {
            remove(toRm);
        }
        else
        {
            test_.log << "Expected " << toRm.string() << " to be an empty existing directory."
                      << std::endl;
        }
    }
 
public:
    DirGuard(beast::unit_test::Suite& test, Path subDir, bool useCounter = true)
        : subDir_(std::move(subDir)), test_(test)
    {
        using namespace std::filesystem;
 
        static auto kSubDirCounter = 0;
        if (useCounter)
            subDir_ += std::to_string(++kSubDirCounter);
        if (!exists(subDir_))
        {
            create_directory(subDir_);
            rmSubDir_ = true;
        }
        else if (is_directory(subDir_))
        {
            rmSubDir_ = false;
        }
        else
        {
            // Cannot run the test. Someone created a file where we want to
            // put our directory
            Throw<std::runtime_error>("Cannot create directory: " + subDir_.string());
        }
    }
 
    ~DirGuard()
    {
        try
        {
            using namespace std::filesystem;
 
            if (rmSubDir_)
                rmDir(subDir_);
        }
        catch (std::exception& e)
        {
            // if we throw here, just let it die.
            test_.log << "Error in ~DirGuard: " << e.what() << std::endl;
        };
    }
 
    [[nodiscard]] Path const&
    subdir() const
    {
        return subDir_;
    }
};

class FileDirGuard : public DirGuard
{
protected:
    Path const file_;
    bool created_ = false;
 
public:
    FileDirGuard(
        beast::unit_test::Suite& test,
        Path subDir,
        Path file,
        std::string const& contents,
        bool useCounter = true,
        bool create = true)
        : DirGuard(test, subDir, useCounter), file_(file.is_absolute() ? file : subdir() / file)
    {
        if (!exists(file_))
        {
            if (create)
            {
                std::ofstream o(file_.string());
                o << contents;
                created_ = true;
            }
        }
        else
        {
            Throw<std::runtime_error>("Refusing to overwrite existing file: " + file_.string());
        }
    }
 
    ~FileDirGuard()
    {
        try
        {
            using namespace std::filesystem;
            if (exists(file_))
            {
                remove(file_);
            }
            else
            {
                if (created_)
                {
                    test_.log << "Expected " << file_.string() << " to be an existing file."
                              << std::endl;
                }
            }
        }
        catch (std::exception& e)
        {
            // if we throw here, just let it die.
            test_.log << "Error in ~FileGuard: " << e.what() << std::endl;
        };
    }
 
    [[nodiscard]] Path const&
    file() const
    {
        return file_;
    }
 
    [[nodiscard]] bool
    fileExists() const
    {
        return std::filesystem::exists(file_);
    }
};
 
}  // namespace xrpl::detail