[extractor] Import `_ALL_CLASSES` lazily

This significantly speeds up `import yt_dlp` in the absence of `lazy_extractors`

1 files changed, 23 insertions, 0 deletions

diff --git a/yt_dlp/extractor/extractors.py b/yt_dlp/extractor/extractors.py
new file mode 100644
index 000000000..32818a024
--- /dev/null
+++ b/yt_dlp/extractor/extractors.py
@@ -0,0 +1,23 @@
+import contextlib
+import os
+
+from ..utils import load_plugins
+
+_LAZY_LOADER = False
+if not os.environ.get('YTDLP_NO_LAZY_EXTRACTORS'):
+    with contextlib.suppress(ImportError):
+        from .lazy_extractors import *  # noqa: F403
+        from .lazy_extractors import _ALL_CLASSES
+        _LAZY_LOADER = True
+
+if not _LAZY_LOADER:
+    from ._extractors import *  # noqa: F403
+    _ALL_CLASSES = [  # noqa: F811
+        klass
+        for name, klass in globals().items()
+        if name.endswith('IE') and name != 'GenericIE'
+    ]
+    _ALL_CLASSES.append(GenericIE)  # noqa: F405
+
+_PLUGIN_CLASSES = load_plugins('extractor', 'IE', globals())
+_ALL_CLASSES = list(_PLUGIN_CLASSES.values()) + _ALL_CLASSES