Asynchronous Reads for Dirmonitor (#930)

Change dirmonitor reads to be synchronous, in a secondary thread.

src/api/dirmonitor/inotify.c

@@ -1,58 +1,53 @@
 #include <sys/inotify.h>
-#include <limits.h>
-#include <unistd.h>
+#include <sys/select.h>
 #include <stdlib.h>
-#include <string.h>
-#include <errno.h>
-#include <fcntl.h>
+#include <unistd.h>
 
-struct dirmonitor {
+
+struct dirmonitor_internal {
   int fd;
+  // a pipe is used to wake the thread in case of exit
+  int sig[2];
 };
 
-struct dirmonitor* init_dirmonitor_inotify() {
-  struct dirmonitor* monitor = calloc(sizeof(struct dirmonitor), 1);
 
+struct dirmonitor_internal* init_dirmonitor() {
+  struct dirmonitor_internal* monitor = calloc(sizeof(struct dirmonitor_internal), 1);
   monitor->fd = inotify_init();
-  fcntl(monitor->fd, F_SETFL, O_NONBLOCK);
-
-
+  pipe(monitor->sig);
   return monitor;
 }
 
-void deinit_dirmonitor_inotify(struct dirmonitor* monitor) {
+
+void deinit_dirmonitor(struct dirmonitor_internal* monitor) {
+  close(monitor->sig[0]);
+  close(monitor->sig[1]);
   close(monitor->fd);
-  free(monitor);
 }
 
-int check_dirmonitor_inotify(struct dirmonitor* monitor, int (*change_callback)(int, const char*, void*), void* data) {
-  char buf[PATH_MAX + sizeof(struct inotify_event)];
-  ssize_t offset = 0;
 
-  while (1) {
-    ssize_t len = read(monitor->fd, &buf[offset], sizeof(buf) - offset);
-
-    if (len == -1 && errno != EAGAIN) {
-      return errno;
-    }
-
-    if (len <= 0) {
-      return 0;
-    }
-
-    while (len > sizeof(struct inotify_event) && len >= ((struct inotify_event*)buf)->len + sizeof(struct inotify_event)) {
-      change_callback(((const struct inotify_event *)buf)->wd, NULL, data);
-      len -= sizeof(struct inotify_event) + ((struct inotify_event*)buf)->len;
-      memmove(buf, &buf[sizeof(struct inotify_event) + ((struct inotify_event*)buf)->len], len);
-      offset = len;
-    }
-  }
+int get_changes_dirmonitor(struct dirmonitor_internal* monitor, char* buffer, int length) {
+  fd_set set;
+  FD_ZERO(&set);
+  FD_SET(monitor->fd, &set);
+  FD_SET(monitor->sig[0], &set);
+  select(FD_SETSIZE, &set, NULL, NULL, NULL);
+  return read(monitor->fd, buffer, length);
 }
 
-int add_dirmonitor_inotify(struct dirmonitor* monitor, const char* path) {
+
+int translate_changes_dirmonitor(struct dirmonitor_internal* monitor, char* buffer, int length, int (*change_callback)(int, const char*, void*), void* data) {
+  for (struct inotify_event* info = (struct inotify_event*)buffer; (char*)info < buffer + length; info = (struct inotify_event*)((char*)info + sizeof(struct inotify_event)))
+    change_callback(info->wd, NULL, data);
+  return 0;
+}
+
+
+int add_dirmonitor(struct dirmonitor_internal* monitor, const char* path) {
   return inotify_add_watch(monitor->fd, path, IN_CREATE | IN_DELETE | IN_MOVED_FROM | IN_MOVED_TO);
 }
 
-void remove_dirmonitor_inotify(struct dirmonitor* monitor, int fd) {
+
+void remove_dirmonitor(struct dirmonitor_internal* monitor, int fd) {
   inotify_rm_watch(monitor->fd, fd);
-}
+}