xemu/scripts/qapi/parser.py
Markus Armbruster 8ec0e1a4e6 qapi: Brush off some (py)lint
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200304155932.20452-5-armbru@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
2020-03-05 09:24:11 +01:00

580 lines
21 KiB
Python

# -*- coding: utf-8 -*-
#
# QAPI schema parser
#
# Copyright IBM, Corp. 2011
# Copyright (c) 2013-2019 Red Hat Inc.
#
# Authors:
# Anthony Liguori <aliguori@us.ibm.com>
# Markus Armbruster <armbru@redhat.com>
# Marc-André Lureau <marcandre.lureau@redhat.com>
# Kevin Wolf <kwolf@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2.
# See the COPYING file in the top-level directory.
import os
import re
from collections import OrderedDict
from qapi.error import QAPIParseError, QAPISemError
from qapi.source import QAPISourceInfo
class QAPISchemaParser:
def __init__(self, fname, previously_included=None, incl_info=None):
previously_included = previously_included or set()
previously_included.add(os.path.abspath(fname))
try:
fp = open(fname, 'r', encoding='utf-8')
self.src = fp.read()
except IOError as e:
raise QAPISemError(incl_info or QAPISourceInfo(None, None, None),
"can't read %s file '%s': %s"
% ("include" if incl_info else "schema",
fname,
e.strerror))
if self.src == '' or self.src[-1] != '\n':
self.src += '\n'
self.cursor = 0
self.info = QAPISourceInfo(fname, 1, incl_info)
self.line_pos = 0
self.exprs = []
self.docs = []
self.accept()
cur_doc = None
while self.tok is not None:
info = self.info
if self.tok == '#':
self.reject_expr_doc(cur_doc)
cur_doc = self.get_doc(info)
self.docs.append(cur_doc)
continue
expr = self.get_expr(False)
if 'include' in expr:
self.reject_expr_doc(cur_doc)
if len(expr) != 1:
raise QAPISemError(info, "invalid 'include' directive")
include = expr['include']
if not isinstance(include, str):
raise QAPISemError(info,
"value of 'include' must be a string")
incl_fname = os.path.join(os.path.dirname(fname),
include)
self.exprs.append({'expr': {'include': incl_fname},
'info': info})
exprs_include = self._include(include, info, incl_fname,
previously_included)
if exprs_include:
self.exprs.extend(exprs_include.exprs)
self.docs.extend(exprs_include.docs)
elif "pragma" in expr:
self.reject_expr_doc(cur_doc)
if len(expr) != 1:
raise QAPISemError(info, "invalid 'pragma' directive")
pragma = expr['pragma']
if not isinstance(pragma, dict):
raise QAPISemError(
info, "value of 'pragma' must be an object")
for name, value in pragma.items():
self._pragma(name, value, info)
else:
expr_elem = {'expr': expr,
'info': info}
if cur_doc:
if not cur_doc.symbol:
raise QAPISemError(
cur_doc.info, "definition documentation required")
expr_elem['doc'] = cur_doc
self.exprs.append(expr_elem)
cur_doc = None
self.reject_expr_doc(cur_doc)
@staticmethod
def reject_expr_doc(doc):
if doc and doc.symbol:
raise QAPISemError(
doc.info,
"documentation for '%s' is not followed by the definition"
% doc.symbol)
def _include(self, include, info, incl_fname, previously_included):
incl_abs_fname = os.path.abspath(incl_fname)
# catch inclusion cycle
inf = info
while inf:
if incl_abs_fname == os.path.abspath(inf.fname):
raise QAPISemError(info, "inclusion loop for %s" % include)
inf = inf.parent
# skip multiple include of the same file
if incl_abs_fname in previously_included:
return None
return QAPISchemaParser(incl_fname, previously_included, info)
def _pragma(self, name, value, info):
if name == 'doc-required':
if not isinstance(value, bool):
raise QAPISemError(info,
"pragma 'doc-required' must be boolean")
info.pragma.doc_required = value
elif name == 'returns-whitelist':
if (not isinstance(value, list)
or any([not isinstance(elt, str) for elt in value])):
raise QAPISemError(
info,
"pragma returns-whitelist must be a list of strings")
info.pragma.returns_whitelist = value
elif name == 'name-case-whitelist':
if (not isinstance(value, list)
or any([not isinstance(elt, str) for elt in value])):
raise QAPISemError(
info,
"pragma name-case-whitelist must be a list of strings")
info.pragma.name_case_whitelist = value
else:
raise QAPISemError(info, "unknown pragma '%s'" % name)
def accept(self, skip_comment=True):
while True:
self.tok = self.src[self.cursor]
self.pos = self.cursor
self.cursor += 1
self.val = None
if self.tok == '#':
if self.src[self.cursor] == '#':
# Start of doc comment
skip_comment = False
self.cursor = self.src.find('\n', self.cursor)
if not skip_comment:
self.val = self.src[self.pos:self.cursor]
return
elif self.tok in '{}:,[]':
return
elif self.tok == "'":
# Note: we accept only printable ASCII
string = ''
esc = False
while True:
ch = self.src[self.cursor]
self.cursor += 1
if ch == '\n':
raise QAPIParseError(self, "missing terminating \"'\"")
if esc:
# Note: we recognize only \\ because we have
# no use for funny characters in strings
if ch != '\\':
raise QAPIParseError(self,
"unknown escape \\%s" % ch)
esc = False
elif ch == '\\':
esc = True
continue
elif ch == "'":
self.val = string
return
if ord(ch) < 32 or ord(ch) >= 127:
raise QAPIParseError(
self, "funny character in string")
string += ch
elif self.src.startswith('true', self.pos):
self.val = True
self.cursor += 3
return
elif self.src.startswith('false', self.pos):
self.val = False
self.cursor += 4
return
elif self.tok == '\n':
if self.cursor == len(self.src):
self.tok = None
return
self.info = self.info.next_line()
self.line_pos = self.cursor
elif not self.tok.isspace():
# Show up to next structural, whitespace or quote
# character
match = re.match('[^[\\]{}:,\\s\'"]+',
self.src[self.cursor-1:])
raise QAPIParseError(self, "stray '%s'" % match.group(0))
def get_members(self):
expr = OrderedDict()
if self.tok == '}':
self.accept()
return expr
if self.tok != "'":
raise QAPIParseError(self, "expected string or '}'")
while True:
key = self.val
self.accept()
if self.tok != ':':
raise QAPIParseError(self, "expected ':'")
self.accept()
if key in expr:
raise QAPIParseError(self, "duplicate key '%s'" % key)
expr[key] = self.get_expr(True)
if self.tok == '}':
self.accept()
return expr
if self.tok != ',':
raise QAPIParseError(self, "expected ',' or '}'")
self.accept()
if self.tok != "'":
raise QAPIParseError(self, "expected string")
def get_values(self):
expr = []
if self.tok == ']':
self.accept()
return expr
if self.tok not in "{['tfn":
raise QAPIParseError(
self, "expected '{', '[', ']', string, boolean or 'null'")
while True:
expr.append(self.get_expr(True))
if self.tok == ']':
self.accept()
return expr
if self.tok != ',':
raise QAPIParseError(self, "expected ',' or ']'")
self.accept()
def get_expr(self, nested):
if self.tok != '{' and not nested:
raise QAPIParseError(self, "expected '{'")
if self.tok == '{':
self.accept()
expr = self.get_members()
elif self.tok == '[':
self.accept()
expr = self.get_values()
elif self.tok in "'tfn":
expr = self.val
self.accept()
else:
raise QAPIParseError(
self, "expected '{', '[', string, boolean or 'null'")
return expr
def get_doc(self, info):
if self.val != '##':
raise QAPIParseError(
self, "junk after '##' at start of documentation comment")
doc = QAPIDoc(self, info)
self.accept(False)
while self.tok == '#':
if self.val.startswith('##'):
# End of doc comment
if self.val != '##':
raise QAPIParseError(
self,
"junk after '##' at end of documentation comment")
doc.end_comment()
self.accept()
return doc
doc.append(self.val)
self.accept(False)
raise QAPIParseError(self, "documentation comment must end with '##'")
class QAPIDoc:
"""
A documentation comment block, either definition or free-form
Definition documentation blocks consist of
* a body section: one line naming the definition, followed by an
overview (any number of lines)
* argument sections: a description of each argument (for commands
and events) or member (for structs, unions and alternates)
* features sections: a description of each feature flag
* additional (non-argument) sections, possibly tagged
Free-form documentation blocks consist only of a body section.
"""
class Section:
def __init__(self, name=None):
# optional section name (argument/member or section name)
self.name = name
# the list of lines for this section
self.text = ''
def append(self, line):
self.text += line.rstrip() + '\n'
class ArgSection(Section):
def __init__(self, name):
super().__init__(name)
self.member = None
def connect(self, member):
self.member = member
def __init__(self, parser, info):
# self._parser is used to report errors with QAPIParseError. The
# resulting error position depends on the state of the parser.
# It happens to be the beginning of the comment. More or less
# servicable, but action at a distance.
self._parser = parser
self.info = info
self.symbol = None
self.body = QAPIDoc.Section()
# dict mapping parameter name to ArgSection
self.args = OrderedDict()
self.features = OrderedDict()
# a list of Section
self.sections = []
# the current section
self._section = self.body
self._append_line = self._append_body_line
def has_section(self, name):
"""Return True if we have a section with this name."""
for i in self.sections:
if i.name == name:
return True
return False
def append(self, line):
"""
Parse a comment line and add it to the documentation.
The way that the line is dealt with depends on which part of
the documentation we're parsing right now:
* The body section: ._append_line is ._append_body_line
* An argument section: ._append_line is ._append_args_line
* A features section: ._append_line is ._append_features_line
* An additional section: ._append_line is ._append_various_line
"""
line = line[1:]
if not line:
self._append_freeform(line)
return
if line[0] != ' ':
raise QAPIParseError(self._parser, "missing space after #")
line = line[1:]
self._append_line(line)
def end_comment(self):
self._end_section()
@staticmethod
def _is_section_tag(name):
return name in ('Returns:', 'Since:',
# those are often singular or plural
'Note:', 'Notes:',
'Example:', 'Examples:',
'TODO:')
def _append_body_line(self, line):
"""
Process a line of documentation text in the body section.
If this a symbol line and it is the section's first line, this
is a definition documentation block for that symbol.
If it's a definition documentation block, another symbol line
begins the argument section for the argument named by it, and
a section tag begins an additional section. Start that
section and append the line to it.
Else, append the line to the current section.
"""
name = line.split(' ', 1)[0]
# FIXME not nice: things like '# @foo:' and '# @foo: ' aren't
# recognized, and get silently treated as ordinary text
if not self.symbol and not self.body.text and line.startswith('@'):
if not line.endswith(':'):
raise QAPIParseError(self._parser, "line should end with ':'")
self.symbol = line[1:-1]
# FIXME invalid names other than the empty string aren't flagged
if not self.symbol:
raise QAPIParseError(self._parser, "invalid name")
elif self.symbol:
# This is a definition documentation block
if name.startswith('@') and name.endswith(':'):
self._append_line = self._append_args_line
self._append_args_line(line)
elif line == 'Features:':
self._append_line = self._append_features_line
elif self._is_section_tag(name):
self._append_line = self._append_various_line
self._append_various_line(line)
else:
self._append_freeform(line.strip())
else:
# This is a free-form documentation block
self._append_freeform(line.strip())
def _append_args_line(self, line):
"""
Process a line of documentation text in an argument section.
A symbol line begins the next argument section, a section tag
section or a non-indented line after a blank line begins an
additional section. Start that section and append the line to
it.
Else, append the line to the current section.
"""
name = line.split(' ', 1)[0]
if name.startswith('@') and name.endswith(':'):
line = line[len(name)+1:]
self._start_args_section(name[1:-1])
elif self._is_section_tag(name):
self._append_line = self._append_various_line
self._append_various_line(line)
return
elif (self._section.text.endswith('\n\n')
and line and not line[0].isspace()):
if line == 'Features:':
self._append_line = self._append_features_line
else:
self._start_section()
self._append_line = self._append_various_line
self._append_various_line(line)
return
self._append_freeform(line.strip())
def _append_features_line(self, line):
name = line.split(' ', 1)[0]
if name.startswith('@') and name.endswith(':'):
line = line[len(name)+1:]
self._start_features_section(name[1:-1])
elif self._is_section_tag(name):
self._append_line = self._append_various_line
self._append_various_line(line)
return
elif (self._section.text.endswith('\n\n')
and line and not line[0].isspace()):
self._start_section()
self._append_line = self._append_various_line
self._append_various_line(line)
return
self._append_freeform(line.strip())
def _append_various_line(self, line):
"""
Process a line of documentation text in an additional section.
A symbol line is an error.
A section tag begins an additional section. Start that
section and append the line to it.
Else, append the line to the current section.
"""
name = line.split(' ', 1)[0]
if name.startswith('@') and name.endswith(':'):
raise QAPIParseError(self._parser,
"'%s' can't follow '%s' section"
% (name, self.sections[0].name))
if self._is_section_tag(name):
line = line[len(name)+1:]
self._start_section(name[:-1])
if (not self._section.name or
not self._section.name.startswith('Example')):
line = line.strip()
self._append_freeform(line)
def _start_symbol_section(self, symbols_dict, name):
# FIXME invalid names other than the empty string aren't flagged
if not name:
raise QAPIParseError(self._parser, "invalid parameter name")
if name in symbols_dict:
raise QAPIParseError(self._parser,
"'%s' parameter name duplicated" % name)
assert not self.sections
self._end_section()
self._section = QAPIDoc.ArgSection(name)
symbols_dict[name] = self._section
def _start_args_section(self, name):
self._start_symbol_section(self.args, name)
def _start_features_section(self, name):
self._start_symbol_section(self.features, name)
def _start_section(self, name=None):
if name in ('Returns', 'Since') and self.has_section(name):
raise QAPIParseError(self._parser,
"duplicated '%s' section" % name)
self._end_section()
self._section = QAPIDoc.Section(name)
self.sections.append(self._section)
def _end_section(self):
if self._section:
text = self._section.text = self._section.text.strip()
if self._section.name and (not text or text.isspace()):
raise QAPIParseError(
self._parser,
"empty doc section '%s'" % self._section.name)
self._section = None
def _append_freeform(self, line):
match = re.match(r'(@\S+:)', line)
if match:
raise QAPIParseError(self._parser,
"'%s' not allowed in free-form documentation"
% match.group(1))
self._section.append(line)
def connect_member(self, member):
if member.name not in self.args:
# Undocumented TODO outlaw
self.args[member.name] = QAPIDoc.ArgSection(member.name)
self.args[member.name].connect(member)
def connect_feature(self, feature):
if feature.name not in self.features:
raise QAPISemError(feature.info,
"feature '%s' lacks documentation"
% feature.name)
self.features[feature.name].connect(feature)
def check_expr(self, expr):
if self.has_section('Returns') and 'command' not in expr:
raise QAPISemError(self.info,
"'Returns:' is only valid for commands")
def check(self):
def check_args_section(args, info, what):
bogus = [name for name, section in args.items()
if not section.member]
if bogus:
raise QAPISemError(
self.info,
"documented member%s '%s' %s not exist"
% ("s" if len(bogus) > 1 else "",
"', '".join(bogus),
"do" if len(bogus) > 1 else "does"))
check_args_section(self.args, self.info, 'members')
check_args_section(self.features, self.info, 'features')