win: use long directory name for handle->dirw

`uv_relative_path` assumes `dir` is a prefix of `filename`, which is not
the case when `handle->dirw` is a short path.

Refs: https://github.com/nodejs/node/issues/19170
PR-URL: https://github.com/libuv/libuv/pull/1769
Reviewed-By: Bartosz Sosnowski <bartosz@janeasystems.com>

src/win/fs-event.c

@@ -69,6 +69,7 @@ static void uv_relative_path(const WCHAR* filename,
   size_t relpathlen;
   size_t filenamelen = wcslen(filename);
   size_t dirlen = wcslen(dir);
+  assert(!_wcsnicmp(filename, dir, dirlen));
   if (dirlen > 0 && dir[dirlen - 1] == '\\')
     dirlen--;
   relpathlen = filenamelen - dirlen - 1;
@@ -151,11 +152,11 @@ int uv_fs_event_start(uv_fs_event_t* handle,
                       uv_fs_event_cb cb,
                       const char* path,
                       unsigned int flags) {
-  int name_size, is_path_dir;
+  int name_size, is_path_dir, size;
   DWORD attr, last_error;
   WCHAR* dir = NULL, *dir_to_watch, *pathw = NULL;
   WCHAR short_path_buffer[MAX_PATH];
-  WCHAR* short_path;
+  WCHAR* short_path, *long_path;
 
   if (uv__is_active(handle))
     return UV_EINVAL;
@@ -197,6 +198,30 @@ int uv_fs_event_start(uv_fs_event_t* handle,
 
   if (is_path_dir) {
      /* path is a directory, so that's the directory that we will watch. */
+
+    /* Convert to long path. */
+    size = GetLongPathNameW(pathw, NULL, 0);
+
+    if (size) {
+      long_path = (WCHAR*)uv__malloc(size * sizeof(WCHAR));
+      if (!long_path) {
+        uv_fatal_error(ERROR_OUTOFMEMORY, "uv__malloc");
+      }
+
+      size = GetLongPathNameW(pathw, long_path, size);
+      if (size) {
+        long_path[size] = '\0';
+      } else {
+        uv__free(long_path);
+        long_path = NULL;
+      }
+    }
+
+    if (long_path) {
+      uv__free(pathw);
+      pathw = long_path;
+    }
+
     dir_to_watch = pathw;
   } else {
     /*

test/test-fs-event.c

@@ -129,7 +129,7 @@ static void fs_event_cb_dir(uv_fs_event_t* handle, const char* filename,
   ++fs_event_cb_called;
   ASSERT(handle == &fs_event);
   ASSERT(status == 0);
-  ASSERT(events == UV_RENAME);
+  ASSERT(events == UV_CHANGE);
   #if defined(__APPLE__) || defined(_WIN32) || defined(__linux__)
   ASSERT(strcmp(filename, "file1") == 0);
   #else
@@ -477,6 +477,42 @@ TEST_IMPL(fs_event_watch_dir_recursive) {
 #endif
 }
 
+#ifdef _WIN32
+TEST_IMPL(fs_event_watch_dir_short_path) {
+  uv_loop_t* loop;
+  int r;
+
+  /* Setup */
+  loop = uv_default_loop();
+  remove("watch_dir/file1");
+  remove("watch_dir/");
+  create_dir("watch_dir");
+  create_file("watch_dir/file1");
+
+  r = uv_fs_event_init(loop, &fs_event);
+  ASSERT(r == 0);
+  r = uv_fs_event_start(&fs_event, fs_event_cb_dir, "watch_~1", 0);
+  ASSERT(r == 0);
+  r = uv_timer_init(loop, &timer);
+  ASSERT(r == 0);
+  r = uv_timer_start(&timer, timer_cb_file, 100, 0);
+  ASSERT(r == 0);
+
+  uv_run(loop, UV_RUN_DEFAULT);
+
+  ASSERT(fs_event_cb_called == 1);
+  ASSERT(timer_cb_called == 1);
+  ASSERT(close_cb_called == 1);
+
+  /* Cleanup */
+  remove("watch_dir/file1");
+  remove("watch_dir/");
+
+  MAKE_VALGRIND_HAPPY();
+  return 0;
+}
+#endif
+
 
 TEST_IMPL(fs_event_watch_file) {
 #if defined(NO_FS_EVENTS)

test/test-list.h

@@ -301,6 +301,9 @@ TEST_DECLARE   (fs_stat_missing_path)
 TEST_DECLARE   (fs_read_file_eof)
 TEST_DECLARE   (fs_event_watch_dir)
 TEST_DECLARE   (fs_event_watch_dir_recursive)
+#ifdef _WIN32
+TEST_DECLARE   (fs_event_watch_dir_short_path)
+#endif
 TEST_DECLARE   (fs_event_watch_file)
 TEST_DECLARE   (fs_event_watch_file_exact_path)
 TEST_DECLARE   (fs_event_watch_file_twice)
@@ -828,6 +831,9 @@ TASK_LIST_START
   TEST_ENTRY  (fs_file_open_append)
   TEST_ENTRY  (fs_event_watch_dir)
   TEST_ENTRY  (fs_event_watch_dir_recursive)
+#ifdef _WIN32
+  TEST_ENTRY  (fs_event_watch_dir_short_path)
+#endif
   TEST_ENTRY  (fs_event_watch_file)
   TEST_ENTRY  (fs_event_watch_file_exact_path)
   TEST_ENTRY  (fs_event_watch_file_twice)