INotify.cpp

// SPDX-FileCopyrightText: 2018 Lutz Freitag
// SPDX-License-Identifier: MIT
#include "INotify.h"

#include <linux/limits.h>

#include <algorithm>
#include <array>
#include <cerrno>

namespace simplyfile {

INotify::INotify(int flags)
    : FileDescriptor(::inotify_init1(flags))
{}

void INotify::watch(std::string const& _path, uint32_t mask) {
    int id = inotify_add_watch(*this, _path.c_str(), mask);
    mIDs[id] = _path;
}

void INotify::unwatch(std::string const& _path) {
    auto it = std::find_if(mIDs.begin(), mIDs.end(), [&](auto const& p) { return p.second == _path; });
    if (it == mIDs.end()) {
        return;
    }
    inotify_rm_watch(*this, it->first);
}


void INotify::unwatch_all() {
    for (auto const& [id, p] : mIDs)  {
        inotify_rm_watch(*this, id);
    }
}

auto INotify::readEvent() -> std::optional<INotify::Result> {
    std::array<std::byte, sizeof(inotify_event) + NAME_MAX + 1> buffer;
    int r = read(*this, buffer.data(), buffer.size());
    if (r <= 0 and (errno == EAGAIN || errno == EWOULDBLOCK)) {
        return {};
    }
    inotify_event const& event = *reinterpret_cast<inotify_event const*>(buffer.data());

    if (0 == event.wd) {
        return std::nullopt;
    }

    INotify::Result res;
    res.path = mIDs.at(event.wd);
    if (event.len > 0) {
        res.file = event.name;
    }

    return res;
}

}