Add fsevents backend to dirmonitor (#1141)

* dirmonitor: added backend reporting of watch mode

* dirmonitor: added fsevents backend for macos

data/core/dirwatch.lua

@@ -14,8 +14,8 @@ function dirwatch.new()
     watched = {},
     reverse_watched = {},
     monitor = dirmonitor.new(),
-    windows_watch_top = nil,
-    windows_watch_count = 0
+    single_watch_top = nil,
+    single_watch_count = 0
   }
   setmetatable(t, dirwatch)
   return t
@@ -38,23 +38,23 @@ function dirwatch:watch(directory, bool)
   local info = system.get_file_info(directory)
   if not info then return end
   if not self.watched[directory] and not self.scanned[directory] then
-    if PLATFORM == "Windows" then
+    if self.monitor:mode() == "single" then
       if info.type ~= "dir" then return self:scan(directory) end
-      if not self.windows_watch_top or directory:find(self.windows_watch_top, 1, true) ~= 1 then
+      if not self.single_watch_top or directory:find(self.single_watch_top, 1, true) ~= 1 then
         -- Get the highest level of directory that is common to this directory, and the original.
         local target = directory
-        while self.windows_watch_top and self.windows_watch_top:find(target, 1, true) ~= 1 do
+        while self.single_watch_top and self.single_watch_top:find(target, 1, true) ~= 1 do
           target = common.dirname(target)
         end
-        if target ~= self.windows_watch_top then
+        if target ~= self.single_watch_top then
           local value = self.monitor:watch(target)
           if value and value < 0 then
             return self:scan(directory)
           end
-          self.windows_watch_top = target
+          self.single_watch_top = target
         end
       end
-      self.windows_watch_count = self.windows_watch_count + 1
+      self.single_watch_count = self.single_watch_count + 1
       self.watched[directory] = true
     else
       local value = self.monitor:watch(directory)
@@ -72,13 +72,13 @@ end
 -- this should be an absolute path
 function dirwatch:unwatch(directory)
   if self.watched[directory] then
-    if PLATFORM ~= "Windows" then
+    if self.monitor:mode() == "multiple" then
       self.monitor:unwatch(self.watched[directory])
       self.reverse_watched[directory] = nil
     else
-      self.windows_watch_count = self.windows_watch_count - 1
-      if self.windows_watch_count == 0 then
-        self.windows_watch_top = nil
+      self.single_watch_count = self.single_watch_count - 1
+      if self.single_watch_count == 0 then
+        self.single_watch_top = nil
         self.monitor:unwatch(directory)
       end
     end
@@ -93,8 +93,12 @@ function dirwatch:check(change_callback, scan_time, wait_time)
   local had_change = false
   self.monitor:check(function(id)
     had_change = true
-    if PLATFORM == "Windows" then
-      change_callback(common.dirname(self.windows_watch_top .. PATHSEP .. id))
+    if self.monitor:mode() == "single" then
+      local path = common.dirname(id)
+      if not string.match(id, "^/") and not string.match(id, "^%a:[/\\]") then
+        path = common.dirname(self.single_watch_top .. PATHSEP .. id)
+      end
+      change_callback(path)
     elseif self.reverse_watched[id] then
       change_callback(self.reverse_watched[id])
     end

meson_options.txt

@@ -2,4 +2,4 @@ option('bundle', type : 'boolean', value : false, description: 'Build a macOS bu
 option('source-only', type : 'boolean', value : false, description: 'Configure source files only, doesn\'t checks for dependencies')
 option('portable', type : 'boolean', value : false, description: 'Portable install')
 option('renderer', type : 'boolean', value : false, description: 'Use SDL renderer')
-option('dirmonitor_backend', type : 'combo', value : '', choices : ['', 'inotify', 'kqueue', 'win32', 'dummy'], description: 'define what dirmonitor backend to use')
+option('dirmonitor_backend', type : 'combo', value : '', choices : ['', 'inotify', 'fsevents', 'kqueue', 'win32', 'dummy'], description: 'define what dirmonitor backend to use')

src/api/dirmonitor.c

@@ -23,6 +23,7 @@ int get_changes_dirmonitor(struct dirmonitor_internal*, char*, int);
 int translate_changes_dirmonitor(struct dirmonitor_internal*, char*, int, int (*)(int, const char*, void*), void*);
 int add_dirmonitor(struct dirmonitor_internal*, const char*);
 void remove_dirmonitor(struct dirmonitor_internal*, int);
+int get_mode_dirmonitor();
 
 
 static int f_check_dir_callback(int watch_id, const char* path, void* L) {
@@ -111,12 +112,23 @@ static int f_dirmonitor_check(lua_State* L) {
 }
 
 
+static int f_dirmonitor_mode(lua_State* L) {
+  int mode = get_mode_dirmonitor();
+  if (mode == 1)
+    lua_pushstring(L, "single");
+  else
+    lua_pushstring(L, "multiple");
+  return 1;
+}
+
+
 static const luaL_Reg dirmonitor_lib[] = {
   { "new",      f_dirmonitor_new         },
   { "__gc",     f_dirmonitor_gc          },
   { "watch",    f_dirmonitor_watch       },
   { "unwatch",  f_dirmonitor_unwatch     },
   { "check",    f_dirmonitor_check       },
+  { "mode",     f_dirmonitor_mode        },
   {NULL, NULL}
 };
 

src/api/dirmonitor/dummy.c

@@ -6,3 +6,4 @@ int get_changes_dirmonitor(struct dirmonitor_internal* monitor, char* buffer, si
 int translate_changes_dirmonitor(struct dirmonitor_internal* monitor, char* buffer, int size, int (*callback)(int, const char*, void*), void* data) { return -1; }
 int add_dirmonitor(struct dirmonitor_internal* monitor, const char* path) { return -1; }
 void remove_dirmonitor(struct dirmonitor_internal* monitor, int fd) { }
+int get_mode_dirmonitor() { return 1; }

src/api/dirmonitor/fsevents.c

@@ -0,0 +1,181 @@
+#include <SDL.h>
+#include <CoreServices/CoreServices.h>
+
+struct dirmonitor_internal {
+  SDL_mutex* lock;
+  char** changes;
+  size_t count;
+  FSEventStreamRef stream;
+};
+
+CFRunLoopRef main_run_loop;
+
+
+struct dirmonitor_internal* init_dirmonitor() {
+  static bool mainloop_registered = false;
+  if (!mainloop_registered) {
+    main_run_loop = CFRunLoopGetCurrent();
+    mainloop_registered = true;
+  }
+
+  struct dirmonitor_internal* monitor = malloc(sizeof(struct dirmonitor_internal));
+  monitor->stream = NULL;
+  monitor->changes = NULL;
+  monitor->count = 0;
+
+  return monitor;
+}
+
+
+static void stop_monitor_stream(struct dirmonitor_internal* monitor) {
+  if (monitor->stream) {
+    FSEventStreamStop(monitor->stream);
+    FSEventStreamUnscheduleFromRunLoop(
+      monitor->stream, main_run_loop, kCFRunLoopDefaultMode
+    );
+    FSEventStreamInvalidate(monitor->stream);
+    FSEventStreamRelease(monitor->stream);
+    monitor->stream = NULL;
+
+    SDL_LockMutex(monitor->lock);
+    if (monitor->count > 0) {
+      for (size_t i = 0; i<monitor->count; i++) {
+        free(monitor->changes[i]);
+      }
+      free(monitor->changes);
+      monitor->changes = NULL;
+      monitor->count = 0;
+    }
+    SDL_UnlockMutex(monitor->lock);
+    SDL_DestroyMutex(monitor->lock);
+  }
+}
+
+
+void deinit_dirmonitor(struct dirmonitor_internal* monitor) {
+  stop_monitor_stream(monitor);
+}
+
+
+static void stream_callback(
+  ConstFSEventStreamRef streamRef,
+  void* monitor_ptr,
+  size_t numEvents,
+  void* eventPaths,
+  const FSEventStreamEventFlags eventFlags[],
+  const FSEventStreamEventId eventIds[]
+)
+{
+  if (numEvents <= 0) {
+    return;
+  }
+
+  struct dirmonitor_internal* monitor = monitor_ptr;
+  char** path_list = eventPaths;
+
+  SDL_LockMutex(monitor->lock);
+  size_t total = 0;
+  if (monitor->count == 0) {
+    total = numEvents;
+    monitor->changes = calloc(numEvents, sizeof(char*));
+  } else {
+    total = monitor->count + numEvents;
+    monitor->changes = realloc(
+      monitor->changes,
+      sizeof(char*) * total
+    );
+  }
+  for (size_t idx = monitor->count; idx < total; idx++) {
+    size_t pidx = idx - monitor->count;
+    monitor->changes[idx] = malloc(strlen(path_list[pidx])+1);
+    strcpy(monitor->changes[idx], path_list[pidx]);
+  }
+  monitor->count = total;
+  SDL_UnlockMutex(monitor->lock);
+}
+
+
+int get_changes_dirmonitor(
+  struct dirmonitor_internal* monitor,
+  char* buffer,
+  int buffer_size
+) {
+  FSEventStreamFlushSync(monitor->stream);
+
+  size_t results = 0;
+  SDL_LockMutex(monitor->lock);
+  results = monitor->count;
+  SDL_UnlockMutex(monitor->lock);
+
+  return results;
+}
+
+
+int translate_changes_dirmonitor(
+  struct dirmonitor_internal* monitor,
+  char* buffer,
+  int buffer_size,
+  int (*change_callback)(int, const char*, void*),
+  void* L
+) {
+  SDL_LockMutex(monitor->lock);
+  if (monitor->count > 0) {
+    for (size_t i = 0; i<monitor->count; i++) {
+      change_callback(strlen(monitor->changes[i]), monitor->changes[i], L);
+      free(monitor->changes[i]);
+    }
+    free(monitor->changes);
+    monitor->changes = NULL;
+    monitor->count = 0;
+  }
+  SDL_UnlockMutex(monitor->lock);
+  return 0;
+}
+
+
+int add_dirmonitor(struct dirmonitor_internal* monitor, const char* path) {
+  stop_monitor_stream(monitor);
+
+  FSEventStreamContext context = {
+    .info = monitor,
+    .retain = NULL,
+    .release = NULL,
+    .copyDescription = NULL,
+    .version = 0
+  };
+
+  CFStringRef paths[] = {
+    CFStringCreateWithCString(NULL, path, kCFStringEncodingUTF8)
+  };
+
+  monitor->stream = FSEventStreamCreate(
+    NULL,
+    stream_callback,
+    &context,
+    CFArrayCreate(NULL, (const void **)&paths, 1, NULL),
+    kFSEventStreamEventIdSinceNow,
+    10000,
+    kFSEventStreamCreateFlagNone
+      | kFSEventStreamCreateFlagWatchRoot
+      | kFSEventStreamCreateFlagFileEvents
+  );
+
+  FSEventStreamScheduleWithRunLoop(
+    monitor->stream, main_run_loop, kCFRunLoopDefaultMode
+  );
+
+  if (!FSEventStreamStart(monitor->stream)) {
+    stop_monitor_stream(monitor);
+    return -1;
+  }
+
+  return 1;
+}
+
+
+void remove_dirmonitor(struct dirmonitor_internal* monitor, int fd) {
+  stop_monitor_stream(monitor);
+}
+
+
+int get_mode_dirmonitor() { return 1; }

src/api/dirmonitor/inotify.c

@@ -13,7 +13,7 @@ struct dirmonitor_internal {
 
 
 struct dirmonitor_internal* init_dirmonitor() {
-  struct dirmonitor_internal* monitor = calloc(sizeof(struct dirmonitor_internal), 1);
+  struct dirmonitor_internal* monitor = calloc(1, sizeof(struct dirmonitor_internal));
   monitor->fd = inotify_init();
   pipe(monitor->sig);
   fcntl(monitor->sig[0], F_SETFD, FD_CLOEXEC);
@@ -51,3 +51,6 @@ int add_dirmonitor(struct dirmonitor_internal* monitor, const char* path) {
 void remove_dirmonitor(struct dirmonitor_internal* monitor, int fd) {
   inotify_rm_watch(monitor->fd, fd);
 }
+
+
+int get_mode_dirmonitor() { return 2; }

src/api/dirmonitor/kqueue.c

@@ -11,7 +11,7 @@ struct dirmonitor_internal {
 
 
 struct dirmonitor_internal* init_dirmonitor() {
-  struct dirmonitor_internal* monitor = calloc(sizeof(struct dirmonitor_internal), 1);
+  struct dirmonitor_internal* monitor = calloc(1, sizeof(struct dirmonitor_internal));
   monitor->fd = kqueue();
   return monitor;
 }
@@ -53,3 +53,6 @@ int add_dirmonitor(struct dirmonitor_internal* monitor, const char* path) {
 void remove_dirmonitor(struct dirmonitor_internal* monitor, int fd) {
   close(fd);
 }
+
+
+int get_mode_dirmonitor() { return 2; }

src/api/dirmonitor/win32.c

@@ -19,7 +19,7 @@ int get_changes_dirmonitor(struct dirmonitor_internal* monitor, char* buffer, in
 
 
 struct dirmonitor* init_dirmonitor() {
-  return calloc(sizeof(struct dirmonitor_internal), 1);
+  return calloc(1, sizeof(struct dirmonitor_internal));
 }
 
 
@@ -60,3 +60,6 @@ int add_dirmonitor(struct dirmonitor_internal* monitor, const char* path) {
 void remove_dirmonitor(struct dirmonitor_internal* monitor, int fd) {
   close_monitor_handle(monitor);
 }
+
+
+int get_mode_dirmonitor() { return 1; }

src/meson.build

@@ -15,6 +15,8 @@ lite_sources = [
 if get_option('dirmonitor_backend') == ''
     if cc.has_function('inotify_init', prefix : '#include<sys/inotify.h>')
         dirmonitor_backend = 'inotify'
+    elif host_machine.system() == 'darwin' and cc.check_header('CoreServices/CoreServices.h')
+        dirmonitor_backend = 'fsevents'
     elif cc.has_function('kqueue', prefix : '#include<sys/event.h>')
         dirmonitor_backend = 'kqueue'
     elif dependency('libkqueue', required : false).found()