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# event/legacy.py
# Copyright (C) 2005-2021 the SQLAlchemy authors and contributors
# <see AUTHORS file>
#
# This module is part of SQLAlchemy and is released under
# the MIT License: http://www.opensource.org/licenses/mit-license.php
"""Routines to handle adaption of legacy call signatures,
generation of deprecation notes and docstrings.
"""
from .. import util
def _legacy_signature(since, argnames, converter=None):
def leg(fn):
if not hasattr(fn, "_legacy_signatures"):
fn._legacy_signatures = []
fn._legacy_signatures.append((since, argnames, converter))
return fn
return leg
def _wrap_fn_for_legacy(dispatch_collection, fn, argspec):
for since, argnames, conv in dispatch_collection.legacy_signatures:
if argnames[-1] == "**kw":
has_kw = True
argnames = argnames[0:-1]
else:
has_kw = False
if len(argnames) == len(argspec.args) and has_kw is bool(
argspec.varkw
):
if conv:
assert not has_kw
def wrap_leg(*args):
return fn(*conv(*args))
else:
def wrap_leg(*args, **kw):
argdict = dict(zip(dispatch_collection.arg_names, args))
args = [argdict[name] for name in argnames]
if has_kw:
return fn(*args, **kw)
else:
return fn(*args)
return wrap_leg
else:
return fn
def _indent(text, indent):
return "\n".join(indent + line for line in text.split("\n"))
def _standard_listen_example(dispatch_collection, sample_target, fn):
example_kw_arg = _indent(
"\n".join(
"%(arg)s = kw['%(arg)s']" % {"arg": arg}
for arg in dispatch_collection.arg_names[0:2]
),
" ",
)
if dispatch_collection.legacy_signatures:
current_since = max(
since
for since, args, conv in dispatch_collection.legacy_signatures
)
else:
current_since = None
text = (
"from sqlalchemy import event\n\n"
"# standard decorator style%(current_since)s\n"
"@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
"def receive_%(event_name)s("
"%(named_event_arguments)s%(has_kw_arguments)s):\n"
" \"listen for the '%(event_name)s' event\"\n"
"\n # ... (event handling logic) ...\n"
)
if len(dispatch_collection.arg_names) > 3:
text += (
"\n# named argument style (new in 0.9)\n"
"@event.listens_for("
"%(sample_target)s, '%(event_name)s', named=True)\n"
"def receive_%(event_name)s(**kw):\n"
" \"listen for the '%(event_name)s' event\"\n"
"%(example_kw_arg)s\n"
"\n # ... (event handling logic) ...\n"
)
text %= {
"current_since": " (arguments as of %s)" % current_since
if current_since
else "",
"event_name": fn.__name__,
"has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
"named_event_arguments": ", ".join(dispatch_collection.arg_names),
"example_kw_arg": example_kw_arg,
"sample_target": sample_target,
}
return text
def _legacy_listen_examples(dispatch_collection, sample_target, fn):
text = ""
for since, args, conv in dispatch_collection.legacy_signatures:
text += (
"\n# DEPRECATED calling style (pre-%(since)s, "
"will be removed in a future release)\n"
"@event.listens_for(%(sample_target)s, '%(event_name)s')\n"
"def receive_%(event_name)s("
"%(named_event_arguments)s%(has_kw_arguments)s):\n"
" \"listen for the '%(event_name)s' event\"\n"
"\n # ... (event handling logic) ...\n"
% {
"since": since,
"event_name": fn.__name__,
"has_kw_arguments": " **kw"
if dispatch_collection.has_kw
else "",
"named_event_arguments": ", ".join(args),
"sample_target": sample_target,
}
)
return text
def _version_signature_changes(parent_dispatch_cls, dispatch_collection):
since, args, conv = dispatch_collection.legacy_signatures[0]
return (
"\n.. deprecated:: %(since)s\n"
" The :class:`.%(clsname)s.%(event_name)s` event now accepts the \n"
" arguments ``%(named_event_arguments)s%(has_kw_arguments)s``.\n"
" Support for listener functions which accept the previous \n"
' argument signature(s) listed above as "deprecated" will be \n'
" removed in a future release."
% {
"since": since,
"clsname": parent_dispatch_cls.__name__,
"event_name": dispatch_collection.name,
"named_event_arguments": ", ".join(dispatch_collection.arg_names),
"has_kw_arguments": ", **kw" if dispatch_collection.has_kw else "",
}
)
def _augment_fn_docs(dispatch_collection, parent_dispatch_cls, fn):
header = (
".. container:: event_signatures\n\n"
" Example argument forms::\n"
"\n"
)
sample_target = getattr(parent_dispatch_cls, "_target_class_doc", "obj")
text = header + _indent(
_standard_listen_example(dispatch_collection, sample_target, fn),
" " * 8,
)
if dispatch_collection.legacy_signatures:
text += _indent(
_legacy_listen_examples(dispatch_collection, sample_target, fn),
" " * 8,
)
text += _version_signature_changes(
parent_dispatch_cls, dispatch_collection
)
return util.inject_docstring_text(fn.__doc__, text, 1)