Faster directory enumeration algorithm

Also added support for subdirectories.
Works only on Windows.

font_loader/__init__.py

@@ -6,11 +6,10 @@
 from font_loader.font_info import FontInfo, FontStyle
 from font_loader.ttf_parser import TTFFont
 from font_loader.ttc_parser import TTCFont
-from misc import WINDOWS_FONTS_FOLDER, get_app_data_folder
+from misc import WINDOWS_FONTS_FOLDER, get_app_data_folder, enumerate_files_in_directory
 
-SUPPORTED_FONTS_EXTENSIONS = {'.ttf', '.otf', '.ttc'}
 
-is_supported_font = lambda x: os.path.splitext(x)[1].lower() in SUPPORTED_FONTS_EXTENSIONS
+is_supported_font = lambda x: os.path.splitext(x)[1].lower() in {'.ttf', '.otf', '.ttc'}
 
 class FontLoader(object):
     def __init__(self, font_dirs = None, load_system_fonts = True):
@@ -56,7 +55,8 @@ def get_fonts_for_list(self, font_names):
         return found, not_found
 
     def __enumerate_font_files(self, directory):
-        return [os.path.join(directory, x) for x in filter(is_supported_font, os.listdir(directory))]
+        files =  enumerate_files_in_directory(directory)
+        return [x['path'] for x in files if is_supported_font(x['path'])]
 
     def __enumerate_system_fonts(self):
         system_fonts_paths =  self.__enumerate_font_files(WINDOWS_FONTS_FOLDER)
@@ -90,7 +90,7 @@ def __load_fonts(self, fonts_paths):
         if added or removed:
             # updating the cache
             with open(cache_file, 'w', encoding='utf-8') as file:
-                file.write(FontInfo.FontInfoJsonEncoder(indent=4).encode(self.fonts))
+                file.write(FontInfo.FontInfoJsonEncoder().encode(self.fonts))
 
     def discard_cache(self):
         cache = FontLoader.get_font_cache_file_path()

misc/__init__.py

@@ -1,7 +1,8 @@
 import hashlib
 import os
 import sys
-
+from ctypes import windll, wintypes, byref
+from time import time
 
 class cached_property(object):
     def __init__(self, func, name=None, doc=None):
@@ -19,7 +20,6 @@ def __get__(self, obj, type=None):
             obj.__dict__[self.__name__] = value
         return value
 
-
 def calculate_md5_for_file(path, block_size=2**20):
     md5 = hashlib.md5()
     with open(path, 'rb') as file:
@@ -30,6 +30,44 @@ def calculate_md5_for_file(path, block_size=2**20):
             md5.update(data)
     return md5.hexdigest()
 
+def enumerate_files_in_directory(directory):
+    files = []
+    windows_enumerate_directory(directory, files)
+    return files
+
+def windows_enumerate_directory(directory, files):
+    FILE_ATTRIBUTE_DIRECTORY = 0x10
+    INVALID_HANDLE_VALUE = -1
+    BAN = (u'.', u'..')
+
+    FindFirstFile = windll.kernel32.FindFirstFileW
+    FindNextFile  = windll.kernel32.FindNextFileW
+    FindClose     = windll.kernel32.FindClose
+
+    out  = wintypes.WIN32_FIND_DATAW()
+    fldr = FindFirstFile(os.path.join(directory, "*"), byref(out))
+
+    if fldr == INVALID_HANDLE_VALUE:
+        raise ValueError("invalid handle!")
+    try:
+        while True:
+            if out.cFileName not in BAN:
+                isdir = out.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY
+
+                if isdir:
+                    windows_enumerate_directory(os.path.join(directory, out.cFileName), files)
+                else:
+                    ts = out.ftLastWriteTime
+                    timestamp = (ts.dwLowDateTime << 32) | ts.dwHighDateTime
+                    size = out.nFileSizeLow
+                    path = os.path.join(directory, out.cFileName)
+                    files.append({'path': path, 'size': size, 'mod_date':timestamp})
+            if not FindNextFile(fldr, byref(out)):
+                break
+    finally:
+        FindClose(fldr)
+
+
 
 def flag_enum(name, *names):
     #extend frozenset with has_flag method