Use in-house inotify watcher

Signed-off-by: Slendi <slendi@socopon.com>

CMakeLists.txt

@@ -91,19 +91,6 @@ FetchContent_Declare(
 )
 FetchContent_MakeAvailable(cpptrace)
 
-FetchContent_Declare(
-  inotify-cpp
-  GIT_REPOSITORY https://github.com/erikzenker/inotify-cpp.git
-  GIT_TAG "v1.0.0"
-	GIT_SHALLOW 1
-)
-set(BUILD_EXAMPLE OFF)
-set(BUILD_SHARED_LIBS OFF)
-set(BUILD_STATIC_LIBS ON)
-set(BUILD_TEST OFF)
-set(USE_BOOST_FILESYSTEM OFF)
-FetchContent_MakeAvailable(inotify-cpp)
-
 add_subdirectory(vendor)
 
 find_program(WAYLAND_SCANNER wayland-scanner REQUIRED)
@@ -204,6 +191,7 @@ add_executable(waylight
 
 	${CMAKE_CURRENT_SOURCE_DIR}/src/IconRegistry.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/src/Cache.cpp
+	${CMAKE_CURRENT_SOURCE_DIR}/src/InotifyWatcher.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/src/TextRenderer.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/src/ImGui.cpp
 	${CMAKE_CURRENT_SOURCE_DIR}/src/App.cpp
@@ -235,7 +223,6 @@ target_link_libraries(waylight PRIVATE
 	msdfgen::msdfgen-ext
 	lunasvg::lunasvg
 	SQLiteCpp
-	inotify-cpp-static
 
 	m
 	dl
@@ -247,4 +234,3 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "Clang|GNU")
 endif()
 
 install(TARGETS waylight RUNTIME DESTINATION bin)
-

src/Cache.cpp

@@ -11,6 +11,7 @@
 #include <raylib.h>
 
 #include "common.hpp"
+#include <sys/inotify.h>
 
 void replace_all(
     std::string &str, std::string const &from, std::string const &to)
@@ -88,25 +89,37 @@ Cache::Cache(std::shared_ptr<SQLite::Database> db)
 	}
 
 	for (auto const &dir : m_app_dirs) {
-		m_inot.watchPathRecursively(dir);
+		m_inotify.watch_path_recursively(dir);
 	}
 
-	auto events = {
-		inotify::Event::open | inotify::Event::is_dir,
-		inotify::Event::create,
-		inotify::Event::modify,
-		inotify::Event::remove,
-		inotify::Event::move,
-	};
-	m_inot.onEvents(events, [this](auto notification) { rescan(); });
+	m_inotify.set_callback([this](FileWatchEvent const &event) {
+		auto const mask = event.mask;
+		if (mask & IN_Q_OVERFLOW) {
+			rescan();
+			return;
+		}
 
-	m_inot_th = std::thread([this]() { m_inot.run(); });
+		if (mask & IN_ISDIR) {
+			rescan();
+			return;
+		}
+
+		if (mask & (IN_CREATE | IN_DELETE | IN_MODIFY | IN_MOVED_FROM
+		        | IN_MOVED_TO | IN_CLOSE_WRITE)) {
+			if (event.path.extension() == ".desktop") {
+				rescan();
+			}
+		}
+	});
+
+	m_inotify_thread = std::thread([this]() { m_inotify.run(); });
 }
 
 Cache::~Cache()
 {
-	m_inot.stop();
-	m_inot_th.join();
+	m_inotify.stop();
+	if (m_inotify_thread.joinable())
+		m_inotify_thread.join();
 }
 
 void Cache::rescan()

src/Cache.hpp

@@ -7,8 +7,8 @@
 #include <variant>
 #include <vector>
 
+#include "InotifyWatcher.hpp"
 #include <SQLiteCpp/Database.h>
-#include <inotify-cpp/NotifierBuilder.h>
 
 namespace Waylight {
 
@@ -59,8 +59,8 @@ private:
 	std::vector<std::filesystem::path> m_app_dirs;
 	std::shared_ptr<SQLite::Database> m_db;
 
-	inotify::NotifierBuilder m_inot;
-	std::thread m_inot_th;
+	InotifyWatcher m_inotify;
+	std::thread m_inotify_thread;
 };
 
-} // namespace Cache
+} // namespace Waylight

src/InotifyWatcher.cpp

@@ -0,0 +1,241 @@
+#include "InotifyWatcher.hpp"
+
+#include <algorithm>
+#include <array>
+#include <cerrno>
+#include <cstring>
+#include <poll.h>
+#include <stdexcept>
+#include <system_error>
+#include <unistd.h>
+#include <utility>
+
+#include <sys/inotify.h>
+
+namespace Waylight {
+
+namespace {
+constexpr std::uint32_t watch_mask { IN_ATTRIB | IN_CREATE | IN_DELETE
+	| IN_DELETE_SELF | IN_MODIFY | IN_MOVE_SELF | IN_MOVED_FROM | IN_MOVED_TO
+	| IN_CLOSE_WRITE };
+constexpr int poll_timeout_ms { 250 };
+} // namespace
+
+InotifyWatcher::InotifyWatcher()
+    : m_fd(inotify_init1(IN_CLOEXEC))
+{
+	if (m_fd < 0) {
+		throw std::system_error(
+		    errno, std::generic_category(), "inotify_init1 failed");
+	}
+}
+
+InotifyWatcher::~InotifyWatcher()
+{
+	stop();
+
+	if (m_fd >= 0) {
+		::close(m_fd);
+		m_fd = -1;
+	}
+}
+
+void InotifyWatcher::watch_path_recursively(std::filesystem::path const &path)
+{
+	add_watch_recursively(path);
+}
+
+void InotifyWatcher::set_callback(callback_t cb)
+{
+	std::scoped_lock lock(m_watch_mutex);
+	m_callback = std::move(cb);
+}
+
+void InotifyWatcher::run()
+{
+	if (m_running.exchange(true)) {
+		throw std::runtime_error("InotifyWatcher::run called while running");
+	}
+
+	std::array<char, 4096> buffer {};
+	while (m_running.load()) {
+		pollfd fd_set {
+			.fd = m_fd,
+			.events = POLLIN,
+			.revents = 0,
+		};
+
+		int const poll_res { ::poll(&fd_set, 1, poll_timeout_ms) };
+		if (!m_running.load())
+			break;
+
+		if (poll_res < 0) {
+			if (errno == EINTR)
+				continue;
+			if (errno == EBADF || errno == EINVAL)
+				break;
+			throw std::system_error(errno, std::generic_category(), "poll");
+		}
+
+		if (poll_res == 0)
+			continue;
+
+		if (fd_set.revents & (POLLERR | POLLHUP | POLLNVAL))
+			break;
+
+		if (!(fd_set.revents & POLLIN))
+			continue;
+
+		ssize_t const bytes_read { ::read(m_fd, buffer.data(), buffer.size()) };
+		if (bytes_read < 0) {
+			if (errno == EINTR || errno == EAGAIN)
+				continue;
+			if (errno == EBADF || errno == EINVAL)
+				break;
+			throw std::system_error(errno, std::generic_category(), "read");
+		}
+
+		ssize_t offset { 0 };
+		while (offset + static_cast<ssize_t>(sizeof(inotify_event))
+		    <= bytes_read) {
+			auto const *event = reinterpret_cast<inotify_event const *>(
+			    buffer.data() + offset);
+			std::string_view name;
+			if (event->len > 0) {
+				auto const *raw_name
+				    = buffer.data() + offset + sizeof(inotify_event);
+				auto const *end
+				    = std::find(raw_name, raw_name + event->len, '\0');
+				name = std::string_view(raw_name, end - raw_name);
+			}
+
+			dispatch_event(event->wd, event->mask, name);
+
+			offset += sizeof(inotify_event) + event->len;
+		}
+	}
+
+	m_running.store(false);
+}
+
+void InotifyWatcher::stop() { m_running.store(false); }
+
+void InotifyWatcher::add_watch_for_path(std::filesystem::path const &path)
+{
+	auto normalized { normalize_path(path) };
+	if (normalized.empty())
+		return;
+
+	auto const key = normalized.string();
+	{
+		std::scoped_lock lock(m_watch_mutex);
+		auto it = m_path_to_watch.find(key);
+		if (it != m_path_to_watch.end())
+			return;
+	}
+
+	int const wd { ::inotify_add_watch(m_fd, normalized.c_str(), watch_mask) };
+	if (wd < 0) {
+		if (errno == ENOENT || errno == ENOTDIR)
+			return;
+		throw std::system_error(errno, std::generic_category(),
+		    "inotify_add_watch failed for " + normalized.string());
+	}
+
+	std::scoped_lock lock(m_watch_mutex);
+	m_watch_to_path.emplace(wd, normalized);
+	m_path_to_watch.emplace(key, wd);
+}
+
+void InotifyWatcher::add_watch_recursively(std::filesystem::path const &path)
+{
+	auto normalized = normalize_path(path);
+	if (normalized.empty())
+		return;
+
+	add_watch_for_path(normalized);
+
+	std::error_code ec;
+	if (!std::filesystem::is_directory(normalized, ec))
+		return;
+
+	try {
+		auto const options {
+			std::filesystem::directory_options::follow_directory_symlink
+			| std::filesystem::directory_options::skip_permission_denied
+		};
+		for (auto const &entry : std::filesystem::recursive_directory_iterator(
+		         normalized, options)) {
+			std::error_code inner_ec;
+			if (!entry.is_directory(inner_ec) || inner_ec)
+				continue;
+			add_watch_for_path(entry.path());
+		}
+	} catch (std::filesystem::filesystem_error const &) {
+	}
+}
+
+void InotifyWatcher::remove_watch(int wd)
+{
+	std::filesystem::path removed_path;
+	{
+		std::scoped_lock lock(m_watch_mutex);
+		auto it { m_watch_to_path.find(wd) };
+		if (it == m_watch_to_path.end())
+			return;
+		removed_path = it->second;
+		m_watch_to_path.erase(it);
+		m_path_to_watch.erase(removed_path.string());
+	}
+
+	::inotify_rm_watch(m_fd, wd);
+}
+
+void InotifyWatcher::dispatch_event(
+    int wd, std::uint32_t mask, std::string_view name)
+{
+	std::filesystem::path base_path;
+	callback_t callback_copy;
+	{
+		std::scoped_lock lock(m_watch_mutex);
+		auto it { m_watch_to_path.find(wd) };
+		if (it == m_watch_to_path.end())
+			return;
+		base_path = it->second;
+		callback_copy = m_callback;
+	}
+
+	auto event_path { base_path };
+	if (!name.empty())
+		event_path /= name;
+
+	if ((mask & IN_ISDIR)
+	    && (mask & (IN_CREATE | IN_MOVED_TO | IN_ATTRIB | IN_CLOSE_WRITE))) {
+		add_watch_recursively(event_path);
+	}
+
+	if (mask & (IN_DELETE_SELF | IN_MOVE_SELF | IN_IGNORED)) {
+		remove_watch(wd);
+	}
+
+	if (callback_copy) {
+		callback_copy(FileWatchEvent {
+		    .path = std::move(event_path),
+		    .mask = mask,
+		});
+	}
+}
+
+std::filesystem::path InotifyWatcher::normalize_path(
+    std::filesystem::path const &path)
+{
+	std::error_code ec;
+	auto normalized { std::filesystem::weakly_canonical(path, ec) };
+	if (ec)
+		normalized = std::filesystem::absolute(path, ec);
+	if (ec)
+		return {};
+	return normalized;
+}
+
+} // namespace Waylight

src/InotifyWatcher.hpp

@@ -0,0 +1,57 @@
+#pragma once
+
+#include <atomic>
+#include <cstdint>
+#include <filesystem>
+#include <functional>
+#include <mutex>
+#include <string>
+#include <string_view>
+#include <unordered_map>
+
+namespace Waylight {
+
+struct FileWatchEvent {
+	std::filesystem::path path;
+	std::uint32_t mask;
+};
+
+class InotifyWatcher {
+public:
+	using callback_t = std::function<void(FileWatchEvent const &)>;
+
+	InotifyWatcher();
+	~InotifyWatcher();
+
+	InotifyWatcher(InotifyWatcher const &) = delete;
+	InotifyWatcher &operator=(InotifyWatcher const &) = delete;
+
+	InotifyWatcher(InotifyWatcher &&) = delete;
+	InotifyWatcher &operator=(InotifyWatcher &&) = delete;
+
+	void watch_path_recursively(std::filesystem::path const &path);
+
+	void set_callback(callback_t cb);
+
+	void run();
+	void stop();
+
+private:
+	void add_watch_for_path(std::filesystem::path const &path);
+	void add_watch_recursively(std::filesystem::path const &path);
+	void remove_watch(int wd);
+
+	void dispatch_event(int wd, std::uint32_t mask, std::string_view name);
+	static std::filesystem::path normalize_path(
+	    std::filesystem::path const &path);
+
+	int m_fd;
+	std::atomic<bool> m_running { false };
+	callback_t m_callback;
+
+	std::mutex m_watch_mutex;
+	std::unordered_map<int, std::filesystem::path> m_watch_to_path;
+	std::unordered_map<std::string, int> m_path_to_watch;
+};
+
+} // namespace Waylight

src/enum_array.hpp

@@ -11,8 +11,7 @@ template<class E>
 concept EnumLike = std::is_enum_v<E>;
 
 template<EnumLike E>
-constexpr usize enum_count_v
-    = static_cast<usize>(enum_traits<E>::last)
+constexpr usize enum_count_v = static_cast<usize>(enum_traits<E>::last)
     - static_cast<usize>(enum_traits<E>::first) + 1;
 
 template<EnumLike E, class T> struct enum_array {