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qemu/scripts/qapi/parser.py

789 lines
29 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.
from collections import OrderedDict
import os
import re
from typing import (
TYPE_CHECKING,
Any,
Dict,
List,
Mapping,
Match,
Optional,
Set,
Union,
)
from .common import must_match
from .error import QAPISemError, QAPISourceError
from .source import QAPISourceInfo
if TYPE_CHECKING:
# pylint: disable=cyclic-import
# TODO: Remove cycle. [schema -> expr -> parser -> schema]
from .schema import QAPISchemaFeature, QAPISchemaMember
# Return value alias for get_expr().
_ExprValue = Union[List[object], Dict[str, object], str, bool]
class QAPIExpression(Dict[str, Any]):
# pylint: disable=too-few-public-methods
def __init__(self,
data: Mapping[str, object],
info: QAPISourceInfo,
doc: Optional['QAPIDoc'] = None):
super().__init__(data)
self.info = info
self.doc: Optional['QAPIDoc'] = doc
class QAPIParseError(QAPISourceError):
"""Error class for all QAPI schema parsing errors."""
def __init__(self, parser: 'QAPISchemaParser', msg: str):
col = 1
for ch in parser.src[parser.line_pos:parser.pos]:
if ch == '\t':
col = (col + 7) % 8 + 1
else:
col += 1
super().__init__(parser.info, msg, col)
class QAPISchemaParser:
"""
Parse QAPI schema source.
Parse a JSON-esque schema file and process directives. See
qapi-code-gen.rst section "Schema Syntax" for the exact syntax.
Grammatical validation is handled later by `expr.check_exprs()`.
:param fname: Source file name.
:param previously_included:
The absolute names of previously included source files,
if being invoked from another parser.
:param incl_info:
`QAPISourceInfo` belonging to the parent module.
``None`` implies this is the root module.
:ivar exprs: Resulting parsed expressions.
:ivar docs: Resulting parsed documentation blocks.
:raise OSError: For problems reading the root schema document.
:raise QAPIError: For errors in the schema source.
"""
def __init__(self,
fname: str,
previously_included: Optional[Set[str]] = None,
incl_info: Optional[QAPISourceInfo] = None):
self._fname = fname
self._included = previously_included or set()
self._included.add(os.path.abspath(self._fname))
self.src = ''
# Lexer state (see `accept` for details):
self.info = QAPISourceInfo(self._fname, incl_info)
self.tok: Union[None, str] = None
self.pos = 0
self.cursor = 0
self.val: Optional[Union[bool, str]] = None
self.line_pos = 0
# Parser output:
self.exprs: List[QAPIExpression] = []
self.docs: List[QAPIDoc] = []
# Showtime!
self._parse()
def _parse(self) -> None:
"""
Parse the QAPI schema document.
:return: None. Results are stored in ``.exprs`` and ``.docs``.
"""
cur_doc = None
# May raise OSError; allow the caller to handle it.
with open(self._fname, 'r', encoding='utf-8') as fp:
self.src = fp.read()
if self.src == '' or self.src[-1] != '\n':
self.src += '\n'
# Prime the lexer:
self.accept()
# Parse until done:
while self.tok is not None:
info = self.info
if self.tok == '#':
self.reject_expr_doc(cur_doc)
cur_doc = self.get_doc()
self.docs.append(cur_doc)
continue
expr = self.get_expr()
if not isinstance(expr, dict):
raise QAPISemError(
info, "top-level expression must be an object")
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(self._fname),
include)
self._add_expr(OrderedDict({'include': incl_fname}), info)
exprs_include = self._include(include, info, incl_fname,
self._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:
if cur_doc and not cur_doc.symbol:
raise QAPISemError(
cur_doc.info, "definition documentation required")
self._add_expr(expr, info, cur_doc)
cur_doc = None
self.reject_expr_doc(cur_doc)
def _add_expr(self, expr: Mapping[str, object],
info: QAPISourceInfo,
doc: Optional['QAPIDoc'] = None) -> None:
self.exprs.append(QAPIExpression(expr, info, doc))
@staticmethod
def reject_expr_doc(doc: Optional['QAPIDoc']) -> None:
if doc and doc.symbol:
raise QAPISemError(
doc.info,
"documentation for '%s' is not followed by the definition"
% doc.symbol)
@staticmethod
def _include(include: str,
info: QAPISourceInfo,
incl_fname: str,
previously_included: Set[str]
) -> Optional['QAPISchemaParser']:
incl_abs_fname = os.path.abspath(incl_fname)
# catch inclusion cycle
inf: Optional[QAPISourceInfo] = 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
try:
return QAPISchemaParser(incl_fname, previously_included, info)
except OSError as err:
raise QAPISemError(
info,
f"can't read include file '{incl_fname}': {err.strerror}"
) from err
@staticmethod
def _pragma(name: str, value: object, info: QAPISourceInfo) -> None:
def check_list_str(name: str, value: object) -> List[str]:
if (not isinstance(value, list) or
any(not isinstance(elt, str) for elt in value)):
raise QAPISemError(
info,
"pragma %s must be a list of strings" % name)
return value
pragma = info.pragma
if name == 'doc-required':
if not isinstance(value, bool):
raise QAPISemError(info,
"pragma 'doc-required' must be boolean")
pragma.doc_required = value
elif name == 'command-name-exceptions':
pragma.command_name_exceptions = check_list_str(name, value)
elif name == 'command-returns-exceptions':
pragma.command_returns_exceptions = check_list_str(name, value)
elif name == 'documentation-exceptions':
pragma.documentation_exceptions = check_list_str(name, value)
elif name == 'member-name-exceptions':
pragma.member_name_exceptions = check_list_str(name, value)
else:
raise QAPISemError(info, "unknown pragma '%s'" % name)
def accept(self, skip_comment: bool = True) -> None:
"""
Read and store the next token.
:param skip_comment:
When false, return COMMENT tokens ("#").
This is used when reading documentation blocks.
:return:
None. Several instance attributes are updated instead:
- ``.tok`` represents the token type. See below for values.
- ``.info`` describes the token's source location.
- ``.val`` is the token's value, if any. See below.
- ``.pos`` is the buffer index of the first character of
the token.
* Single-character tokens:
These are "{", "}", ":", ",", "[", and "]".
``.tok`` holds the single character and ``.val`` is None.
* Multi-character tokens:
* COMMENT:
This token is not normally returned by the lexer, but it can
be when ``skip_comment`` is False. ``.tok`` is "#", and
``.val`` is a string including all chars until end-of-line,
including the "#" itself.
* STRING:
``.tok`` is "'", the single quote. ``.val`` contains the
string, excluding the surrounding quotes.
* TRUE and FALSE:
``.tok`` is either "t" or "f", ``.val`` will be the
corresponding bool value.
* EOF:
``.tok`` and ``.val`` will both be None at EOF.
"""
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 = must_match('[^[\\]{}:,\\s\']+',
self.src[self.cursor-1:])
raise QAPIParseError(self, "stray '%s'" % match.group(0))
def get_members(self) -> Dict[str, object]:
expr: Dict[str, object] = OrderedDict()
if self.tok == '}':
self.accept()
return expr
if self.tok != "'":
raise QAPIParseError(self, "expected string or '}'")
while True:
key = self.val
assert isinstance(key, str) # Guaranteed by tok == "'"
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()
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) -> List[object]:
expr: List[object] = []
if self.tok == ']':
self.accept()
return expr
if self.tok not in tuple("{['tf"):
raise QAPIParseError(
self, "expected '{', '[', ']', string, or boolean")
while True:
expr.append(self.get_expr())
if self.tok == ']':
self.accept()
return expr
if self.tok != ',':
raise QAPIParseError(self, "expected ',' or ']'")
self.accept()
def get_expr(self) -> _ExprValue:
expr: _ExprValue
if self.tok == '{':
self.accept()
expr = self.get_members()
elif self.tok == '[':
self.accept()
expr = self.get_values()
elif self.tok in tuple("'tf"):
assert isinstance(self.val, (str, bool))
expr = self.val
self.accept()
else:
raise QAPIParseError(
self, "expected '{', '[', string, or boolean")
return expr
def get_doc_line(self) -> Optional[str]:
if self.tok != '#':
raise QAPIParseError(
self, "documentation comment must end with '##'")
assert isinstance(self.val, str)
if self.val.startswith('##'):
# End of doc comment
if self.val != '##':
raise QAPIParseError(
self, "junk after '##' at end of documentation comment")
return None
if self.val == '#':
return ''
if self.val[1] != ' ':
raise QAPIParseError(self, "missing space after #")
return self.val[2:].rstrip()
@staticmethod
def _match_at_name_colon(string: str) -> Optional[Match[str]]:
return re.match(r'@([^:]*): *', string)
def get_doc_indented(self, doc: 'QAPIDoc') -> Optional[str]:
self.accept(False)
line = self.get_doc_line()
while line == '':
doc.append_line(line)
self.accept(False)
line = self.get_doc_line()
if line is None:
return line
indent = must_match(r'\s*', line).end()
if not indent:
return line
doc.append_line(line)
prev_line_blank = False
while True:
self.accept(False)
line = self.get_doc_line()
if line is None:
return line
if self._match_at_name_colon(line):
return line
cur_indent = must_match(r'\s*', line).end()
if line != '' and cur_indent < indent:
if prev_line_blank:
return line
raise QAPIParseError(
self,
"unexpected de-indent (expected at least %d spaces)" %
indent)
doc.append_line(line)
prev_line_blank = True
def get_doc_paragraph(self, doc: 'QAPIDoc') -> Optional[str]:
while True:
self.accept(False)
line = self.get_doc_line()
if line is None:
return line
if line == '':
return line
doc.append_line(line)
def get_doc(self) -> 'QAPIDoc':
if self.val != '##':
raise QAPIParseError(
self, "junk after '##' at start of documentation comment")
info = self.info
self.accept(False)
line = self.get_doc_line()
if line is not None and line.startswith('@'):
# Definition documentation
if not line.endswith(':'):
raise QAPIParseError(self, "line should end with ':'")
# Invalid names are not checked here, but the name
# provided *must* match the following definition,
# which *is* validated in expr.py.
symbol = line[1:-1]
if not symbol:
raise QAPIParseError(self, "name required after '@'")
doc = QAPIDoc(info, symbol)
self.accept(False)
line = self.get_doc_line()
no_more_args = False
while line is not None:
# Blank lines
while line == '':
self.accept(False)
line = self.get_doc_line()
if line is None:
break
# Non-blank line, first of a section
if line == 'Features:':
if doc.features:
raise QAPIParseError(
self, "duplicated 'Features:' line")
self.accept(False)
line = self.get_doc_line()
while line == '':
self.accept(False)
line = self.get_doc_line()
while (line is not None
and (match := self._match_at_name_colon(line))):
doc.new_feature(self.info, match.group(1))
text = line[match.end():]
if text:
doc.append_line(text)
line = self.get_doc_indented(doc)
if not doc.features:
raise QAPIParseError(
self, 'feature descriptions expected')
no_more_args = True
elif match := self._match_at_name_colon(line):
# description
if no_more_args:
raise QAPIParseError(
self,
"description of '@%s:' follows a section"
% match.group(1))
while (line is not None
and (match := self._match_at_name_colon(line))):
doc.new_argument(self.info, match.group(1))
text = line[match.end():]
if text:
doc.append_line(text)
line = self.get_doc_indented(doc)
no_more_args = True
elif match := re.match(
r'(Returns|Errors|Since|Notes?|Examples?|TODO)'
r'(?!::): *',
line,
):
# tagged section
# Note: "sections" with two colons are left alone as
# rST markup and not interpreted as a section heading.
# TODO: Remove these errors sometime in 2025 or so
# after we've fully transitioned to the new qapidoc
# generator.
# See commit message for more markup suggestions O:-)
if 'Note' in match.group(1):
emsg = (
f"The '{match.group(1)}' section is no longer "
"supported. Please use rST's '.. note::' or "
"'.. admonition:: notes' directives, or another "
"suitable admonition instead."
)
raise QAPIParseError(self, emsg)
if 'Example' in match.group(1):
emsg = (
f"The '{match.group(1)}' section is no longer "
"supported. Please use the '.. qmp-example::' "
"directive, or other suitable markup instead."
)
raise QAPIParseError(self, emsg)
doc.new_tagged_section(self.info, match.group(1))
text = line[match.end():]
if text:
doc.append_line(text)
line = self.get_doc_indented(doc)
no_more_args = True
elif line.startswith('='):
raise QAPIParseError(
self,
"unexpected '=' markup in definition documentation")
else:
# tag-less paragraph
doc.ensure_untagged_section(self.info)
doc.append_line(line)
line = self.get_doc_paragraph(doc)
else:
# Free-form documentation
doc = QAPIDoc(info)
doc.ensure_untagged_section(self.info)
first = True
while line is not None:
if match := self._match_at_name_colon(line):
raise QAPIParseError(
self,
"'@%s:' not allowed in free-form documentation"
% match.group(1))
if line.startswith('='):
if not first:
raise QAPIParseError(
self,
"'=' heading must come first in a comment block")
doc.append_line(line)
self.accept(False)
line = self.get_doc_line()
first = False
self.accept()
doc.end()
return doc
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:
# pylint: disable=too-few-public-methods
def __init__(self, info: QAPISourceInfo,
tag: Optional[str] = None):
# section source info, i.e. where it begins
self.info = info
# section tag, if any ('Returns', '@name', ...)
self.tag = tag
# section text without tag
self.text = ''
def append_line(self, line: str) -> None:
self.text += line + '\n'
class ArgSection(Section):
def __init__(self, info: QAPISourceInfo, tag: str):
super().__init__(info, tag)
self.member: Optional['QAPISchemaMember'] = None
def connect(self, member: 'QAPISchemaMember') -> None:
self.member = member
def __init__(self, info: QAPISourceInfo, symbol: Optional[str] = None):
# info points to the doc comment block's first line
self.info = info
# definition doc's symbol, None for free-form doc
self.symbol: Optional[str] = symbol
# the sections in textual order
self.all_sections: List[QAPIDoc.Section] = [QAPIDoc.Section(info)]
# the body section
self.body: Optional[QAPIDoc.Section] = self.all_sections[0]
# dicts mapping parameter/feature names to their description
self.args: Dict[str, QAPIDoc.ArgSection] = {}
self.features: Dict[str, QAPIDoc.ArgSection] = {}
# a command's "Returns" and "Errors" section
self.returns: Optional[QAPIDoc.Section] = None
self.errors: Optional[QAPIDoc.Section] = None
# "Since" section
self.since: Optional[QAPIDoc.Section] = None
# sections other than .body, .args, .features
self.sections: List[QAPIDoc.Section] = []
def end(self) -> None:
for section in self.all_sections:
section.text = section.text.strip('\n')
if section.tag is not None and section.text == '':
raise QAPISemError(
section.info, "text required after '%s:'" % section.tag)
def ensure_untagged_section(self, info: QAPISourceInfo) -> None:
if self.all_sections and not self.all_sections[-1].tag:
# extend current section
self.all_sections[-1].text += '\n'
return
# start new section
section = self.Section(info)
self.sections.append(section)
self.all_sections.append(section)
def new_tagged_section(self, info: QAPISourceInfo, tag: str) -> None:
section = self.Section(info, tag)
if tag == 'Returns':
if self.returns:
raise QAPISemError(
info, "duplicated '%s' section" % tag)
self.returns = section
elif tag == 'Errors':
if self.errors:
raise QAPISemError(
info, "duplicated '%s' section" % tag)
self.errors = section
elif tag == 'Since':
if self.since:
raise QAPISemError(
info, "duplicated '%s' section" % tag)
self.since = section
self.sections.append(section)
self.all_sections.append(section)
def _new_description(self, info: QAPISourceInfo, name: str,
desc: Dict[str, ArgSection]) -> None:
if not name:
raise QAPISemError(info, "invalid parameter name")
if name in desc:
raise QAPISemError(info, "'%s' parameter name duplicated" % name)
section = self.ArgSection(info, '@' + name)
self.all_sections.append(section)
desc[name] = section
def new_argument(self, info: QAPISourceInfo, name: str) -> None:
self._new_description(info, name, self.args)
def new_feature(self, info: QAPISourceInfo, name: str) -> None:
self._new_description(info, name, self.features)
def append_line(self, line: str) -> None:
self.all_sections[-1].append_line(line)
def connect_member(self, member: 'QAPISchemaMember') -> None:
if member.name not in self.args:
assert member.info
if self.symbol not in member.info.pragma.documentation_exceptions:
raise QAPISemError(member.info,
"%s '%s' lacks documentation"
% (member.role, member.name))
self.args[member.name] = QAPIDoc.ArgSection(
self.info, '@' + member.name)
self.args[member.name].connect(member)
def connect_feature(self, feature: 'QAPISchemaFeature') -> None:
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: QAPIExpression) -> None:
if 'command' in expr:
if self.returns and 'returns' not in expr:
raise QAPISemError(
self.returns.info,
"'Returns' section, but command doesn't return anything")
else:
if self.returns:
raise QAPISemError(
self.returns.info,
"'Returns' section is only valid for commands")
if self.errors:
raise QAPISemError(
self.errors.info,
"'Errors' section is only valid for commands")
def check(self) -> None:
def check_args_section(
args: Dict[str, QAPIDoc.ArgSection], what: str
) -> None:
bogus = [name for name, section in args.items()
if not section.member]
if bogus:
raise QAPISemError(
args[bogus[0]].info,
"documented %s%s '%s' %s not exist" % (
what,
"s" if len(bogus) > 1 else "",
"', '".join(bogus),
"do" if len(bogus) > 1 else "does"
))
check_args_section(self.args, 'member')
check_args_section(self.features, 'feature')