# -*- coding: utf-8 -*- # # QAPI schema parser # # Copyright IBM, Corp. 2011 # Copyright (c) 2013-2019 Red Hat Inc. # # Authors: # Anthony Liguori # Markus Armbruster # Marc-André Lureau # Kevin Wolf # # 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 ( Dict, List, Optional, Set, Union, ) from .common import must_match from .error import QAPISemError, QAPISourceError from .source import QAPISourceInfo # Return value alias for get_expr(). _ExprValue = Union[List[object], Dict[str, object], str, bool] 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[Dict[str, object]] = [] 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.exprs.append({'expr': {'include': incl_fname}, 'info': 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: 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: 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: 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 = must_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 class NullSection(Section): """ Immutable dummy section for use at the end of a doc block. """ def append(self, line): assert False, "Text appended after end_comment() called." 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._switch_section(QAPIDoc.NullSection(self._parser)) @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] # 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 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 = must_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 = must_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 = must_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 new_section = QAPIDoc.ArgSection(self._parser, name, indent) self._switch_section(new_section) symbols_dict[name] = new_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) new_section = QAPIDoc.Section(self._parser, name, indent) self._switch_section(new_section) self.sections.append(new_section) def _switch_section(self, new_section): text = self._section.text = self._section.text.strip() # 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): 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, what): 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')