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qemu/scripts/qapi/parser.py
Peter Maydell a69a6d4b4d scripts/qapi/parser.py: improve doc comment indent handling 
Make the handling of indentation in doc comments more sophisticated,
so that when we see a section like:

Notes: some text
       some more text
          indented line 3

we save it for the doc-comment processing code as:

some text
some more text
   indented line 3

and when we see a section with the heading on its own line:

Notes:

some text
some more text
   indented text

we also accept that and save it in the same form.

If we detect that the comment document text is not indented as much
as we expect it to be, we throw a parse error.  (We don't complain
about over-indented sections, because for rST this can be legitimate
markup.)

The golden reference for the doc comment text is updated to remove
the two 'wrong' indents; these now form a test case that we correctly
stripped leading whitespace from an indented multi-line argument
definition.

We update the documentation in docs/devel/qapi-code-gen.txt to
describe the new indentation rules.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200925162316.21205-6-peter.maydell@linaro.org>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[Whitespace between sentences tweaked]
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2020-09-29 17:55:39 +02:00

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# -*- 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)
for cur_doc in 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")
docs = []
cur_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")
cur_doc.end_comment()
docs.append(cur_doc)
self.accept()
return docs
if self.val.startswith('# ='):
if cur_doc.symbol:
raise QAPIParseError(
self,
"unexpected '=' markup in definition documentation")
if cur_doc.body.text:
cur_doc.end_comment()
docs.append(cur_doc)
cur_doc = QAPIDoc(self, info)
cur_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, parser, name=None, indent=0):
# parser, for error messages about indentation
self._parser = parser
# optional section name (argument/member or section name)
self.name = name
self.text = ''
# the expected indent level of the text of this section
self._indent = indent
def append(self, line):
# Strip leading spaces corresponding to the expected indent level
# Blank lines are always OK.
if line:
indent = re.match(r'\s*', line).end()
if indent < self._indent:
raise QAPIParseError(
self._parser,
"unexpected de-indent (expected at least %d spaces)" %
self._indent)
line = line[self._indent:]
self.text += line.rstrip() + '\n'
class ArgSection(Section):
def __init__(self, parser, name, indent=0):
super().__init__(parser, name, indent)
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(parser)
# 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)
else:
# This is a free-form documentation block
self._append_freeform(line)
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(':'):
# If line is "@arg: first line of description", find
# the index of 'f', which is the indent we expect for any
# following lines. We then remove the leading "@arg:"
# from line and replace it with spaces so that 'f' has the
# same index as it did in the original line and can be
# handled the same way we will handle following lines.
indent = re.match(r'@\S*:\s*', line).end()
line = line[indent:]
if not line:
# Line was just the "@arg:" header; following lines
# are not indented
indent = 0
else:
line = ' ' * indent + line
self._start_args_section(name[1:-1], indent)
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)
def _append_features_line(self, line):
name = line.split(' ', 1)[0]
if name.startswith('@') and name.endswith(':'):
# If line is "@arg: first line of description", find
# the index of 'f', which is the indent we expect for any
# following lines. We then remove the leading "@arg:"
# from line and replace it with spaces so that 'f' has the
# same index as it did in the original line and can be
# handled the same way we will handle following lines.
indent = re.match(r'@\S*:\s*', line).end()
line = line[indent:]
if not line:
# Line was just the "@arg:" header; following lines
# are not indented
indent = 0
else:
line = ' ' * indent + line
self._start_features_section(name[1:-1], indent)
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)
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):
# If line is "Section: first line of description", find
# the index of 'f', which is the indent we expect for any
# following lines. We then remove the leading "Section:"
# from line and replace it with spaces so that 'f' has the
# same index as it did in the original line and can be
# handled the same way we will handle following lines.
indent = re.match(r'\S*:\s*', line).end()
line = line[indent:]
if not line:
# Line was just the "Section:" header; following lines
# are not indented
indent = 0
else:
line = ' ' * indent + line
self._start_section(name[:-1], indent)
self._append_freeform(line)
def _start_symbol_section(self, symbols_dict, name, indent):
# 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(self._parser, name, indent)
symbols_dict[name] = self._section
def _start_args_section(self, name, indent):
self._start_symbol_section(self.args, name, indent)
def _start_features_section(self, name, indent):
self._start_symbol_section(self.features, name, indent)
def _start_section(self, name=None, indent=0):
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(self._parser, name, indent)
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(self._parser,
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')
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