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# -*- coding: utf-8 -*-
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in the
# documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
# DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
from __future__ import unicode_literals
import json
import types
from collections import deque
from .objects import Object
from .compat import PY3, unicode
class VisitRecursionError(Exception):
pass
class Visited(object):
def __init__(self, result):
if isinstance(result, Visited):
result = result.result
self.result = result
class Visitor(object):
"""
An Object visitor base class that walks the abstract syntax tree and calls a
visitor function for every Object found. This function may return a value
which is forwarded by the `visit` method.
This class is meant to be subclassed, with the subclass adding visitor
methods.
Per default the visitor functions for the nodes are ``'visit_'`` +
class name of the Object. So a `Module` Object visit function would
be `visit_Module`. This behavior can be changed by overriding
the `visit` method. If no visitor function exists for a Object
(return value `None`) the `generic_visit` visitor is used instead.
"""
def __call__(self, obj, metadata):
return self.transform(obj, metadata)
def transform(self, obj, metadata):
"""Transform an Object."""
if isinstance(obj, Object):
method = 'transform_' + obj.__class__.__name__
transformer = getattr(self, method, self.transform_Object)
new_obj = transformer(obj, metadata)
if new_obj is not None and obj is not new_obj:
obj = new_obj
return obj
def transform_Object(self, obj, metadata):
"""Called if no explicit transform function exists for an Object."""
return obj
def generic_visit(self, obj):
return self.visit(self.visit_Object(obj))
def visit(self, obj):
"""Visit a Object."""
if not hasattr(self, 'visitors'):
self._visit_context = {}
self._visit_count = 0
try:
self._visit_count += 1
stack = deque()
stack.append((obj, None))
last_result = None
while stack:
try:
last, visited = stack[-1]
if isinstance(last, types.GeneratorType):
stack.append((last.send(last_result), None))
last_result = None
elif isinstance(last, Visited):
stack.pop()
last_result = last.result
elif isinstance(last, Object):
if last in self._visit_context:
if self._visit_context[last] == self.visit_Object:
visitor = self.visit_RecursionError
else:
visitor = self.visit_Object
else:
method = 'visit_' + last.__class__.__name__
visitor = getattr(self, method, self.visit_Object)
self._visit_context[last] = visitor
stack.pop()
stack.append((visitor(last), last))
else:
method = 'visit_' + last.__class__.__name__
visitor = getattr(self, method, self.visit_Generic)
stack.pop()
stack.append((visitor(last), None))
except StopIteration:
stack.pop()
if visited and visited in self._visit_context:
del self._visit_context[visited]
return last_result
finally:
self._visit_count -= 1
if self._visit_count <= 0:
self._visit_context = {}
def visit_RecursionError(self, obj):
raise VisitRecursionError
def visit_Object(self, obj):
"""Called if no explicit visitor function exists for an Object."""
yield obj.__dict__
yield Visited(obj)
def visit_Generic(self, obj):
"""Called if no explicit visitor function exists for an object."""
yield Visited(obj)
def visit_list(self, obj):
for item in obj:
yield item
yield Visited(obj)
visit_Array = visit_list
def visit_dict(self, obj):
for field, value in list(obj.items()):
if not field.startswith('_'):
yield value
yield Visited(obj)
class NodeVisitor(Visitor):
pass
class ReprVisitor(Visitor):
def visit(self, obj, indent=4, nl="\n", sp="", skip=()):
self.level = 0
if isinstance(indent, int):
indent = " " * indent
self.indent = indent
self.nl = nl
self.sp = sp
self.skip = skip
return super(ReprVisitor, self).visit(obj)
def visit_RecursionError(self, obj):
yield Visited("...")
def visit_Object(self, obj):
value_repr = yield obj.__dict__
yield Visited(value_repr)
def visit_Generic(self, obj):
yield Visited(repr(obj))
def visit_list(self, obj):
indent1 = self.indent * self.level
indent2 = indent1 + self.indent
self.level += 1
try:
items = []
for item in obj:
v = yield item
items.append(v)
if items:
value_repr = "[%s%s%s%s%s%s%s]" % (
self.sp,
self.nl,
indent2,
(",%s%s%s" % (self.nl, self.sp, indent2)).join(items),
self.nl,
indent1,
self.sp,
)
else:
value_repr = "[]"
finally:
self.level -= 1
yield Visited(value_repr)
visit_Array = visit_list
def visit_dict(self, obj):
indent1 = self.indent * self.level
indent2 = indent1 + self.indent
self.level += 1
try:
items = []
for k, item in obj.items():
if item is not None and not k.startswith('_') and k not in self.skip:
v = yield item
items.append("%s: %s" % (k, v))
if items:
value_repr = "{%s%s%s%s%s%s%s}" % (
self.sp,
self.nl,
indent2,
(",%s%s%s" % (self.nl, self.sp, indent2)).join(items),
self.nl,
indent1,
self.sp,
)
else:
value_repr = "{}"
finally:
self.level -= 1
yield Visited(value_repr)
if PY3:
def visit_str(self, obj):
value_repr = json.dumps(obj)
yield Visited(value_repr)
else:
def visit_unicode(self, obj):
value_repr = json.dumps(obj)
yield Visited(value_repr)
def visit_SourceLocation(self, obj):
old_indent, self.indent = self.indent, ""
old_nl, self.nl = self.nl, ""
old_sp, self.sp = self.sp, ""
try:
yield obj
finally:
self.indent = old_indent
self.nl = old_nl
self.sp = old_sp
class ToDictVisitor(Visitor):
map = {
'isAsync': 'async',
'allowAwait': 'await',
}
def visit_RecursionError(self, obj):
yield Visited({
'error': "Infinite recursion detected...",
})
def visit_Object(self, obj):
obj = yield obj.__dict__
yield Visited(obj)
def visit_list(self, obj):
items = []
for item in obj:
v = yield item
items.append(v)
yield Visited(items)
visit_Array = visit_list
def visit_dict(self, obj):
items = []
for k, item in obj.items():
if item is not None and not k.startswith('_'):
v = yield item
k = unicode(k)
items.append((self.map.get(k, k), v))
yield Visited(dict(items))
def visit_SRE_Pattern(self, obj):
yield Visited({})