Created a basic file watcher

src/bakatools/file_system/file_watcher.cpp

@@ -0,0 +1,47 @@
+#include "file_watcher.h"
+
+FileWatcher::FileWatcher(std::string path, TimeSpan<Millisecond> ts)
+: target(path), ttm(ts)
+{
+    for (const std::filesystem::directory_entry& file : std::filesystem::recursive_directory_iterator(target))
+        paths[file.path().string()] = std::filesystem::last_write_time(file);
+}
+
+FileWatcher::~FileWatcher() { stop(); }
+
+void FileWatcher::start(const std::function<void (std::string, FileStatus)>& action)
+{
+    std::function<void()> task([&]()
+    {
+        auto it = paths.begin();
+        while (it != paths.end())
+        {
+            if (!std::filesystem::exists(it->first)) 
+            {
+                action(it->first, FileStatus::Deleted);
+                it = paths.erase(it);
+            }
+            else it++;
+        }
+        for (const std::filesystem::directory_entry& file : std::filesystem::recursive_directory_iterator(target))
+        {
+            auto current_file_last_write_time = std::filesystem::last_write_time(file);
+            if (contains(file.path().string()))
+            {
+                if(paths[file.path().string()] != current_file_last_write_time) {
+                    paths[file.path().string()] = current_file_last_write_time;
+                    action(file.path().string(), FileStatus::Modified);
+                }
+            } else 
+            {
+                paths[file.path().string()] = current_file_last_write_time;
+                action(file.path().string(), FileStatus::Created);
+            }
+        }
+    });
+    ttm.start(std::make_unique<std::function<void()>>(task));
+}
+
+void FileWatcher::stop() { ttm.stop(); }
+
+bool FileWatcher::contains(std::string path) { return paths.find(path) != paths.end(); }

src/bakatools/file_system/file_watcher.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <bakatools.h>
+#include <bakatools/thread/task_timer.h>
+
+enum class FileStatus
+{
+    Created = 0,
+    Modified = 1,
+    Deleted = 2,
+};
+
+class FileWatcher
+{
+    public:
+        FileWatcher(std::string path, TimeSpan<Millisecond> ts);
+        ~FileWatcher();
+
+        void start(const std::function<void (std::string, FileStatus)>& action);
+        void stop();
+        bool contains(std::string path);
+
+    private:
+        std::string target;
+        std::unordered_map<std::string, std::filesystem::file_time_type> paths;
+        TaskTimer<Millisecond> ttm;
+};