1 files changed, 132 insertions, 0 deletions
diff --git a/devscripts/make_lazy_extractors.py b/devscripts/make_lazy_extractors.py
new file mode 100644
index 0000000..d74ea20
--- /dev/null
+++ b/devscripts/make_lazy_extractors.py
@@ -0,0 +1,132 @@
+#!/usr/bin/env python3
+
+# Allow direct execution
+import os
+import shutil
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+from inspect import getsource
+
+from devscripts.utils import get_filename_args, read_file, write_file
+
+NO_ATTR = object()
+STATIC_CLASS_PROPERTIES = [
+    'IE_NAME', '_ENABLED', '_VALID_URL',  # Used for URL matching
+    '_WORKING', 'IE_DESC', '_NETRC_MACHINE', 'SEARCH_KEY',  # Used for --extractor-descriptions
+    'age_limit',  # Used for --age-limit (evaluated)
+    '_RETURN_TYPE',  # Accessed in CLI only with instance (evaluated)
+]
+CLASS_METHODS = [
+    'ie_key', 'suitable', '_match_valid_url',  # Used for URL matching
+    'working', 'get_temp_id', '_match_id',  # Accessed just before instance creation
+    'description',  # Used for --extractor-descriptions
+    'is_suitable',  # Used for --age-limit
+    'supports_login', 'is_single_video',  # Accessed in CLI only with instance
+]
+IE_TEMPLATE = '''
+class {name}({bases}):
+    _module = {module!r}
+'''
+MODULE_TEMPLATE = read_file('devscripts/lazy_load_template.py')
+
+
+def main():
+    lazy_extractors_filename = get_filename_args(default_outfile='yt_dlp/extractor/lazy_extractors.py')
+    if os.path.exists(lazy_extractors_filename):
+        os.remove(lazy_extractors_filename)
+
+    _ALL_CLASSES = get_all_ies()  # Must be before import
+
+    import yt_dlp.plugins
+    from yt_dlp.extractor.common import InfoExtractor, SearchInfoExtractor
+
+    # Filter out plugins
+    _ALL_CLASSES = [cls for cls in _ALL_CLASSES if not cls.__module__.startswith(f'{yt_dlp.plugins.PACKAGE_NAME}.')]
+
+    DummyInfoExtractor = type('InfoExtractor', (InfoExtractor,), {'IE_NAME': NO_ATTR})
+    module_src = '\n'.join((
+        MODULE_TEMPLATE,
+        '    _module = None',
+        *extra_ie_code(DummyInfoExtractor),
+        '\nclass LazyLoadSearchExtractor(LazyLoadExtractor):\n    pass\n',
+        *build_ies(_ALL_CLASSES, (InfoExtractor, SearchInfoExtractor), DummyInfoExtractor),
+    ))
+
+    write_file(lazy_extractors_filename, f'{module_src}\n')
+
+
+def get_all_ies():
+    PLUGINS_DIRNAME = 'ytdlp_plugins'
+    BLOCKED_DIRNAME = f'{PLUGINS_DIRNAME}_blocked'
+    if os.path.exists(PLUGINS_DIRNAME):
+        # os.rename cannot be used, e.g. in Docker. See https://github.com/yt-dlp/yt-dlp/pull/4958
+        shutil.move(PLUGINS_DIRNAME, BLOCKED_DIRNAME)
+    try:
+        from yt_dlp.extractor.extractors import _ALL_CLASSES
+    finally:
+        if os.path.exists(BLOCKED_DIRNAME):
+            shutil.move(BLOCKED_DIRNAME, PLUGINS_DIRNAME)
+    return _ALL_CLASSES
+
+
+def extra_ie_code(ie, base=None):
+    for var in STATIC_CLASS_PROPERTIES:
+        val = getattr(ie, var)
+        if val != (getattr(base, var) if base else NO_ATTR):
+            yield f'    {var} = {val!r}'
+    yield ''
+
+    for name in CLASS_METHODS:
+        f = getattr(ie, name)
+        if not base or f.__func__ != getattr(base, name).__func__:
+            yield getsource(f)
+
+
+def build_ies(ies, bases, attr_base):
+    names = []
+    for ie in sort_ies(ies, bases):
+        yield build_lazy_ie(ie, ie.__name__, attr_base)
+        if ie in ies:
+            names.append(ie.__name__)
+
+    yield f'\n_ALL_CLASSES = [{", ".join(names)}]'
+
+
+def sort_ies(ies, ignored_bases):
+    """find the correct sorting and add the required base classes so that subclasses can be correctly created"""
+    classes, returned_classes = ies[:-1], set()
+    assert ies[-1].__name__ == 'GenericIE', 'Last IE must be GenericIE'
+    while classes:
+        for c in classes[:]:
+            bases = set(c.__bases__) - {object, *ignored_bases}
+            restart = False
+            for b in sorted(bases, key=lambda x: x.__name__):
+                if b not in classes and b not in returned_classes:
+                    assert b.__name__ != 'GenericIE', 'Cannot inherit from GenericIE'
+                    classes.insert(0, b)
+                    restart = True
+            if restart:
+                break
+            if bases <= returned_classes:
+                yield c
+                returned_classes.add(c)
+                classes.remove(c)
+                break
+    yield ies[-1]
+
+
+def build_lazy_ie(ie, name, attr_base):
+    bases = ', '.join({
+        'InfoExtractor': 'LazyLoadExtractor',
+        'SearchInfoExtractor': 'LazyLoadSearchExtractor',
+    }.get(base.__name__, base.__name__) for base in ie.__bases__)
+
+    s = IE_TEMPLATE.format(name=name, module=ie.__module__, bases=bases)
+    return s + '\n'.join(extra_ie_code(ie, attr_base))
+
+
+if __name__ == '__main__':
+    main()