add threaded filewatcher

src/filewatcher/filewatcher.h

@@ -0,0 +1,77 @@
+#ifndef HI_FILEWATCHER_H_
+#define HI_FILEWATCHER_H_
+
+#include "types.h"
+
+/**
+ * File event watching related functionality and types
+ */
+
+typedef enum {
+  HI_FILE_NONE = 0,
+  HI_FILE_ACCESS = 1 << 0,
+  HI_FILE_MODIFY = 1 << 1,
+  HI_FILE_CREATE = 1 << 2,
+  HI_FILE_DELETE = 1 << 3,
+  HI_FILE_ALL =
+      (HI_FILE_ACCESS | HI_FILE_MODIFY | HI_FILE_CREATE | HI_FILE_DELETE)
+} HiFileEventType;
+
+typedef struct {
+  const char *watcher; // Path given to the corresponding wd. Not owning.
+  const char *file; // Owning, should be freed by the event handler by calling
+                    // `hi_file_event_destroy`)
+  HiFileEventType type;
+} hiFileEvent;
+
+struct hiFileWatcherContext;
+/**
+ * FileEvents is a thread safe list of events.
+ *
+ * It is implemented as a stack, so the events will be popped
+ * in reverse chronological order.
+ * */
+struct hiFileEvents;
+
+/**
+ * Create watcher and necessary data to run it.
+ *
+ * Will start the watcher thread immediately.
+ */
+struct hiFileWatcherContext *hi_file_watcher_create();
+/**
+ * Destroy a previously created file watcher context.
+ *
+ * Will join the thread and destroy event stack.
+ */
+void hi_file_watcher_destroy(struct hiFileWatcherContext *context);
+/**
+ * Add a file to the watch list of a file watcher.
+ *
+ * @param context Previously created watcher context
+ * @param pathname Absolute path to the file or directory
+ * @param flags The events that will be watched for
+ */
+HiloadResult hi_file_watcher_add(struct hiFileWatcherContext *context,
+                                 const char *pathname, u32 flags);
+/**
+ * Can be used to poke file watcher thread to make sure it empties
+ * events before doing something, e.g. for shutting it down.
+ */
+void hi_file_watcher_notify(struct hiFileWatcherContext *context);
+
+/**
+ * Frees held memory but doesn't zero fields
+ */
+void hi_file_event_free(hiFileEvent *event);
+/**
+ * Pop an event from event stack. Call `hi_file_event_destroy` when done with
+ * it.
+ */
+hiFileEvent hi_file_event_pop(struct hiFileWatcherContext *ctx);
+/**
+ * Free and zero held memory. Call after pop.
+ */
+void hi_file_event_destroy(hiFileEvent *event);
+
+#endif // HI_FILEWATCHER_H_