File Watcher

Description

FileWatcher is a c++ library that allows you to watch a folder and get notified of any file changes inside.

Features

• watch a file or a folder
• execute the callback for all files
• exported c functions for use in other languages (see example: test_file_watcher.py)

Installation

(Windows only)

Header only

Include the file_watcher.hpp anywhere you want to use it.
And above only one include, define FILE_WATCHER_IMPLEMENTATION like this:

#define FILE_WATCHER_IMPLEMENTATION
#include "file_watcher.hpp"

Header and source

Include the file_watcher.hpp anywhere you want to use it.
Compile with the file_watcher.cpp file or with the built dll available here.

Build the dll

g++ -shared -O3 -fPIC -static -o file_watcher.dll file_watcher.cpp

Note: the -static flag is required.

Requirements

c++17 or later required for compilation.
No external dependencies.

Example

Content of main.cpp

#include <chrono>
#include <iostream>
#include <string>

#include "file_watcher.hpp"

int usage()
{
	std::cout << "Usage: File_Watcher.exe [folderPath]" << std::endl;
	return 1;
}

int main(int argc, const char* argv[])
{
	if (argc != 2) return usage();

	const char* folderPath = argv[1];
	bool bRecursive = true;
	bool bWatching = true;

	file_watcher_watch_async(folderPath, bRecursive, file_watcher_print_file_event, &bWatching, nullptr);

	std::cout << "Press enter to stop watching" << std::endl;
	std::cin.get();

	bWatching = false;

	std::cout << "Watching stopped, press enter to exit" << std::endl;
	std::cin.get();

	return 0;
}

Possible output:

Press enter to stop watching
D:\Projets\C++\File-Watcher\main.cpp modified
D:\Projets\C++\File-Watcher\file_watcher.h removed
D:\Projets\C++\File-Watcher\file_watcher.h added
D:\Projets\C++\File-Watcher\file_watcher.h renamed_old
D:\Projets\C++\File-Watcher\file_watcher.hh renamed_new
D:\Projets\C++\File-Watcher\file_watcher.hh renamed_old
D:\Projets\C++\File-Watcher\file_watcher.h renamed_new

Watching stopped, press enter to exit

Usage

#define EXPORT __declspec(dllexport)

typedef enum
{
	added = 1,
	removed,
	modified,
	renamed_old,
	renamed_new,
} file_watcher_event_type;

static const char* file_watcher_event_type_str[] = {"", "added", "removed", "modified", "renamed_old", "renamed_new"};

#define FILE_WATCHER_FILE_EVENT_PARAM const char *file, file_watcher_event_type event, bool is_directory, void *data
typedef void (*file_watcher_callback)(FILE_WATCHER_FILE_EVENT_PARAM);

extern "C"
{
	// example callback function
	EXPORT void file_watcher_print_file_event(FILE_WATCHER_FILE_EVENT_PARAM);

	// blocking function
	EXPORT void file_watcher_watch_sync(
		const char* folder_path, bool b_recursive, file_watcher_callback callback, void* data = nullptr);

	// non blocking function, change the value of bWatching to stop the thread
	EXPORT void file_watcher_watch_async(const char* folder_path,
		bool b_recursive,
		file_watcher_callback callback,
		bool* bWatching = nullptr,
		void* data = nullptr);
}

Licence

MIT Licence. See LICENSE file. Please refer me with:

Copyright (c) Nicolas VENTER All rights reserved.