mijin2/source/mijin/io/process.cpp

#include "./process.hpp"

#include <algorithm>
#include <sstream>
#include "../util/iterators.hpp"
#include "../util/string.hpp"

namespace mijin
{
ProcessStream::~ProcessStream()
{
    if (handle) {
        close();
    }
}

StreamError ProcessStream::open(const char* command, FileOpenMode mode_)
{
    mode = mode_;
    
    const char* modeStr; // NOLINT(cppcoreguidelines-init-variables)
    switch (mode_)
    {
        case FileOpenMode::READ:
            modeStr = "r";
            break;
        case FileOpenMode::WRITE:
            modeStr = "w";
            break;
        case FileOpenMode::READ_WRITE:
            modeStr = "rw";
            break;
        default:
            assert(!"Unsupported mode for ProcessStream::open()");
            return StreamError::NOT_SUPPORTED;
    }
    handle = popen(command, modeStr); // NOLINT(cppcoreguidelines-owning-memory)
    if (!handle) {
        return StreamError::IO_ERROR;
    }

    return StreamError::SUCCESS;
}

int ProcessStream::close()
{
    assert(handle);
    const int result = pclose(handle);
    handle = nullptr;
    return result;
}

StreamError ProcessStream::readRaw(std::span<std::uint8_t> buffer, bool partial, std::size_t* outBytesRead)
{
    assert(handle);
    assert(mode == FileOpenMode::READ || mode == FileOpenMode::READ_WRITE);

    if (bufferedChar >= 0 && buffer.size() > 0)
    {
        buffer[0] = static_cast<std::uint8_t>(bufferedChar);
    }

    const std::size_t readBytes = std::fread(buffer.data(), 1, buffer.size(), handle);
    if (std::ferror(handle)) {
        return StreamError::IO_ERROR;
    }
    if (!partial && readBytes < buffer.size()) {
        return StreamError::IO_ERROR;
    }
    if (outBytesRead != nullptr)
    {
        *outBytesRead = readBytes + (bufferedChar >= 0 ? 1 : 0);
    }
    bufferedChar = -1;
    return StreamError::SUCCESS;
}

StreamError ProcessStream::writeRaw(std::span<const std::uint8_t> buffer)
{
    assert(handle);
    assert(mode == FileOpenMode::WRITE || mode == FileOpenMode::READ_WRITE);

    const std::size_t written = std::fwrite(buffer.data(), 1, buffer.size(), handle);
    if (written != buffer.size() || std::ferror(handle)) {
        return StreamError::IO_ERROR;
    }

    return StreamError::SUCCESS;
}

std::size_t ProcessStream::tell()
{
    assert(handle);

    return std::ftell(handle); // TODO: does this work?
}

StreamError ProcessStream::seek(std::intptr_t pos, SeekMode seekMode)
{
    (void) pos;
    (void) seekMode;
    return StreamError::NOT_SUPPORTED;
}

void ProcessStream::flush()
{
    const int result = std::fflush(handle);
    assert(result == 0);
}

bool ProcessStream::isAtEnd()
{
    assert(handle);

    if (bufferedChar >= 0) {
        return false;
    }

    bufferedChar = std::fgetc(handle);
    if (std::feof(handle)) {
        return true;
    }
    return false;
}

StreamFeatures ProcessStream::getFeatures()
{
    if (handle)
    {
        return {
            .read = (mode == FileOpenMode::READ),
            .write = (mode == FileOpenMode::WRITE || mode == FileOpenMode::READ_WRITE),
            .tell = true,
            .seek = false
        };
    }
    return {};
}

std::string shellEscape(const std::string& arg) noexcept
{
    std::ostringstream oss;
    const bool requiresQuotes = std::any_of(arg.begin(), arg.end(), [&](const char chr) { return std::isspace(chr); });
    if (requiresQuotes) {
        oss << '"';
    }
    for (const char chr : arg)
    {
        // TODO: oh Windows this will probably be different
        switch (chr)
        {
            case '"':
            case '\'':
            case '\\':
            case '$':
                oss << '\\';
                break;
        }
        oss << chr;
    }
    if (requiresQuotes) {
        oss << '"';
    }
    return oss.str();
}

std::string makeShellCommand(const std::vector<std::string>& args) noexcept
{
    using namespace mijin::pipe;
    return args
        | Map(&shellEscape)
        | Join(" ");
}
} // namespace mijin