| # -*- 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, | 
 |     Dict, | 
 |     List, | 
 |     Mapping, | 
 |     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, object]): | 
 |     # 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.txt 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) | 
 |                 for cur_doc in self.get_doc(info): | 
 |                     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 == '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(self, info: QAPISourceInfo) -> List['QAPIDoc']: | 
 |         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 == '#': | 
 |             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") | 
 |                 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: | 
 |         # pylint: disable=too-few-public-methods | 
 |         def __init__(self, parser: QAPISchemaParser, | 
 |                      name: Optional[str] = None): | 
 |             # parser, for error messages about indentation | 
 |             self._parser = parser | 
 |             # optional section name (argument/member or section name) | 
 |             self.name = name | 
 |             # section text without section name | 
 |             self.text = '' | 
 |             # indentation to strip (None means indeterminate) | 
 |             self._indent = None if self.name else 0 | 
 |  | 
 |         def append(self, line: str) -> None: | 
 |             line = line.rstrip() | 
 |  | 
 |             if line: | 
 |                 indent = must_match(r'\s*', line).end() | 
 |                 if self._indent is None: | 
 |                     # indeterminate indentation | 
 |                     if self.text != '': | 
 |                         # non-blank, non-first line determines indentation | 
 |                         self._indent = indent | 
 |                 elif indent < self._indent: | 
 |                     raise QAPIParseError( | 
 |                         self._parser, | 
 |                         "unexpected de-indent (expected at least %d spaces)" % | 
 |                         self._indent) | 
 |                 line = line[self._indent:] | 
 |  | 
 |             self.text += line + '\n' | 
 |  | 
 |     class ArgSection(Section): | 
 |         def __init__(self, parser: QAPISchemaParser, | 
 |                      name: str): | 
 |             super().__init__(parser, name) | 
 |             self.member: Optional['QAPISchemaMember'] = None | 
 |  | 
 |         def connect(self, member: 'QAPISchemaMember') -> None: | 
 |             self.member = member | 
 |  | 
 |     class NullSection(Section): | 
 |         """ | 
 |         Immutable dummy section for use at the end of a doc block. | 
 |         """ | 
 |         # pylint: disable=too-few-public-methods | 
 |         def append(self, line: str) -> None: | 
 |             assert False, "Text appended after end_comment() called." | 
 |  | 
 |     def __init__(self, parser: QAPISchemaParser, info: QAPISourceInfo): | 
 |         # 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: Optional[str] = None | 
 |         self.body = QAPIDoc.Section(parser) | 
 |         # dicts mapping parameter/feature names to their ArgSection | 
 |         self.args: Dict[str, QAPIDoc.ArgSection] = OrderedDict() | 
 |         self.features: Dict[str, QAPIDoc.ArgSection] = OrderedDict() | 
 |         self.sections: List[QAPIDoc.Section] = [] | 
 |         # the current section | 
 |         self._section = self.body | 
 |         self._append_line = self._append_body_line | 
 |  | 
 |     def has_section(self, name: str) -> bool: | 
 |         """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: str) -> None: | 
 |         """ | 
 |         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) -> None: | 
 |         self._switch_section(QAPIDoc.NullSection(self._parser)) | 
 |  | 
 |     @staticmethod | 
 |     def _match_at_name_colon(string: str): | 
 |         return re.match(r'@([^:]*): *', string) | 
 |  | 
 |     @staticmethod | 
 |     def _match_section_tag(string: str): | 
 |         return re.match(r'(Returns|Since|Notes?|Examples?|TODO): *', string) | 
 |  | 
 |     def _append_body_line(self, line: str) -> None: | 
 |         """ | 
 |         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. | 
 |         """ | 
 |         # 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] | 
 |             # Invalid names are not checked here, but the name provided MUST | 
 |             # match the following definition, which *is* validated in expr.py. | 
 |             if not self.symbol: | 
 |                 raise QAPIParseError( | 
 |                     self._parser, "name required after '@'") | 
 |         elif self.symbol: | 
 |             # This is a definition documentation block | 
 |             if self._match_at_name_colon(line): | 
 |                 self._append_line = self._append_args_line | 
 |                 self._append_args_line(line) | 
 |             elif line == 'Features:': | 
 |                 self._append_line = self._append_features_line | 
 |             elif self._match_section_tag(line): | 
 |                 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: str) -> None: | 
 |         """ | 
 |         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. | 
 |  | 
 |         """ | 
 |         match = self._match_at_name_colon(line) | 
 |         if match: | 
 |             line = line[match.end():] | 
 |             self._start_args_section(match.group(1)) | 
 |         elif self._match_section_tag(line): | 
 |             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: str) -> None: | 
 |         match = self._match_at_name_colon(line) | 
 |         if match: | 
 |             line = line[match.end():] | 
 |             self._start_features_section(match.group(1)) | 
 |         elif self._match_section_tag(line): | 
 |             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: str) -> None: | 
 |         """ | 
 |         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. | 
 |         """ | 
 |         match = self._match_at_name_colon(line) | 
 |         if match: | 
 |             raise QAPIParseError(self._parser, | 
 |                                  "description of '@%s:' follows a section" | 
 |                                  % match.group(1)) | 
 |         match = self._match_section_tag(line) | 
 |         if match: | 
 |             line = line[match.end():] | 
 |             self._start_section(match.group(1)) | 
 |  | 
 |         self._append_freeform(line) | 
 |  | 
 |     def _start_symbol_section( | 
 |             self, | 
 |             symbols_dict: Dict[str, 'QAPIDoc.ArgSection'], | 
 |             name: str) -> None: | 
 |         # 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 | 
 |         new_section = QAPIDoc.ArgSection(self._parser, name) | 
 |         self._switch_section(new_section) | 
 |         symbols_dict[name] = new_section | 
 |  | 
 |     def _start_args_section(self, name: str) -> None: | 
 |         self._start_symbol_section(self.args, name) | 
 |  | 
 |     def _start_features_section(self, name: str) -> None: | 
 |         self._start_symbol_section(self.features, name) | 
 |  | 
 |     def _start_section(self, name: Optional[str] = None) -> None: | 
 |         if name in ('Returns', 'Since') and self.has_section(name): | 
 |             raise QAPIParseError(self._parser, | 
 |                                  "duplicated '%s' section" % name) | 
 |         new_section = QAPIDoc.Section(self._parser, name) | 
 |         self._switch_section(new_section) | 
 |         self.sections.append(new_section) | 
 |  | 
 |     def _switch_section(self, new_section: 'QAPIDoc.Section') -> None: | 
 |         text = self._section.text = self._section.text.strip('\n') | 
 |  | 
 |         # Only the 'body' section is allowed to have an empty body. | 
 |         # All other sections, including anonymous ones, must have text. | 
 |         if self._section != self.body and not text: | 
 |             # We do not create anonymous sections unless there is | 
 |             # something to put in them; this is a parser bug. | 
 |             assert self._section.name | 
 |             raise QAPIParseError( | 
 |                 self._parser, | 
 |                 "empty doc section '%s'" % self._section.name) | 
 |  | 
 |         self._section = new_section | 
 |  | 
 |     def _append_freeform(self, line: str) -> None: | 
 |         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: 'QAPISchemaMember') -> None: | 
 |         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: '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 self.has_section('Returns') and 'command' not in expr: | 
 |             raise QAPISemError(self.info, | 
 |                                "'Returns:' 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( | 
 |                     self.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') |