blob: 868fb45f338e90e04b85355e42bac543e296f951 [file] [log] [blame]
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Generates a syntax tree from a Mojo IDL file."""
import imp
import os.path
import sys
def _GetDirAbove(dirname):
"""Returns the directory "above" this file containing |dirname| (which must
also be "above" this file)."""
path = os.path.abspath(__file__)
while True:
path, tail = os.path.split(path)
assert tail
if tail == dirname:
return path
except ImportError:
sys.path.append(os.path.join(_GetDirAbove("mojo"), "third_party"))
from ply import lex
from ply import yacc
from ..error import Error
from . import ast
from .lexer import Lexer
_MAX_ORDINAL_VALUE = 0xffffffff
_MAX_ARRAY_SIZE = 0xffffffff
class ParseError(Error):
"""Class for errors from the parser."""
def __init__(self, filename, message, lineno=None, snippet=None):
Error.__init__(self, filename, message, lineno=lineno,
addenda=([snippet] if snippet else None))
# We have methods which look like they could be functions:
# pylint: disable=R0201
class Parser(object):
def __init__(self, lexer, source, filename):
self.tokens = lexer.tokens
self.source = source
self.filename = filename
# Names of functions
# In general, we name functions after the left-hand-side of the rule(s) that
# they handle. E.g., |p_foo_bar| for a rule |foo_bar : ...|.
# There may be multiple functions handling rules for the same left-hand-side;
# then we name the functions |p_foo_bar_N| (for left-hand-side |foo_bar|),
# where N is a number (numbered starting from 1). Note that using multiple
# functions is actually more efficient than having single functions handle
# multiple rules (and, e.g., distinguishing them by examining |len(p)|).
# It's also possible to have a function handling multiple rules with different
# left-hand-sides. We do not do this.
# See for more details.
# TODO(vtl): Get rid of the braces in the module "statement". (Consider
# renaming "module" -> "package".) Then we'll be able to have a single rule
# for root (by making module "optional").
def p_root_1(self, p):
"""root : """
p[0] = ast.Mojom(None, ast.ImportList(), [])
def p_root_2(self, p):
"""root : root module"""
if p[1].module is not None:
raise ParseError(self.filename,
"Multiple \"module\" statements not allowed:",
p[2].lineno, snippet=self._GetSnippet(p[2].lineno))
if p[1].import_list.items or p[1].definition_list:
raise ParseError(
"\"module\" statements must precede imports and definitions:",
p[2].lineno, snippet=self._GetSnippet(p[2].lineno))
p[0] = p[1]
p[0].module = p[2]
def p_root_3(self, p):
"""root : root import"""
if p[1].definition_list:
raise ParseError(self.filename,
"\"import\" statements must precede definitions:",
p[2].lineno, snippet=self._GetSnippet(p[2].lineno))
p[0] = p[1]
def p_root_4(self, p):
"""root : root definition"""
p[0] = p[1]
def p_import(self, p):
# 'eval' the literal to strip the quotes.
# TODO(vtl): This eval is dubious. We should unquote/unescape ourselves.
p[0] = ast.Import(eval(p[2]), filename=self.filename, lineno=p.lineno(2))
def p_module(self, p):
"""module : attribute_section MODULE identifier_wrapped SEMI"""
p[0] = ast.Module(p[3], p[1], filename=self.filename, lineno=p.lineno(2))
def p_definition(self, p):
"""definition : struct
| union
| interface
| enum
| const"""
p[0] = p[1]
def p_attribute_section_1(self, p):
"""attribute_section : """
p[0] = None
def p_attribute_section_2(self, p):
"""attribute_section : LBRACKET attribute_list RBRACKET"""
p[0] = p[2]
def p_attribute_list_1(self, p):
"""attribute_list : """
p[0] = ast.AttributeList()
def p_attribute_list_2(self, p):
"""attribute_list : nonempty_attribute_list"""
p[0] = p[1]
def p_nonempty_attribute_list_1(self, p):
"""nonempty_attribute_list : attribute"""
p[0] = ast.AttributeList(p[1])
def p_nonempty_attribute_list_2(self, p):
"""nonempty_attribute_list : nonempty_attribute_list COMMA attribute"""
p[0] = p[1]
def p_attribute_1(self, p):
"""attribute : NAME EQUALS evaled_literal
p[0] = ast.Attribute(p[1], p[3], filename=self.filename, lineno=p.lineno(1))
def p_attribute_2(self, p):
"""attribute : NAME"""
p[0] = ast.Attribute(p[1], True, filename=self.filename, lineno=p.lineno(1))
def p_evaled_literal(self, p):
"""evaled_literal : literal"""
# 'eval' the literal to strip the quotes. Handle keywords "true" and "false"
# specially since they cannot directly be evaluated to python boolean
# values.
if p[1] == "true":
p[0] = True
elif p[1] == "false":
p[0] = False
p[0] = eval(p[1])
def p_struct_1(self, p):
"""struct : attribute_section STRUCT NAME LBRACE struct_body RBRACE SEMI"""
p[0] = ast.Struct(p[3], p[1], p[5])
def p_struct_2(self, p):
"""struct : attribute_section STRUCT NAME SEMI"""
p[0] = ast.Struct(p[3], p[1], None)
def p_struct_body_1(self, p):
"""struct_body : """
p[0] = ast.StructBody()
def p_struct_body_2(self, p):
"""struct_body : struct_body const
| struct_body enum
| struct_body struct_field"""
p[0] = p[1]
def p_struct_field(self, p):
"""struct_field : attribute_section typename NAME ordinal default SEMI"""
p[0] = ast.StructField(p[3], p[1], p[4], p[2], p[5])
def p_union(self, p):
"""union : attribute_section UNION NAME LBRACE union_body RBRACE SEMI"""
p[0] = ast.Union(p[3], p[1], p[5])
def p_union_body_1(self, p):
"""union_body : """
p[0] = ast.UnionBody()
def p_union_body_2(self, p):
"""union_body : union_body union_field"""
p[0] = p[1]
def p_union_field(self, p):
"""union_field : attribute_section typename NAME ordinal SEMI"""
p[0] = ast.UnionField(p[3], p[1], p[4], p[2])
def p_default_1(self, p):
"""default : """
p[0] = None
def p_default_2(self, p):
"""default : EQUALS constant"""
p[0] = p[2]
def p_interface(self, p):
"""interface : attribute_section INTERFACE NAME LBRACE interface_body \
p[0] = ast.Interface(p[3], p[1], p[5])
def p_interface_body_1(self, p):
"""interface_body : """
p[0] = ast.InterfaceBody()
def p_interface_body_2(self, p):
"""interface_body : interface_body const
| interface_body enum
| interface_body method"""
p[0] = p[1]
def p_response_1(self, p):
"""response : """
p[0] = None
def p_response_2(self, p):
"""response : RESPONSE LPAREN parameter_list RPAREN"""
p[0] = p[3]
def p_method(self, p):
"""method : attribute_section NAME ordinal LPAREN parameter_list RPAREN \
response SEMI"""
p[0] = ast.Method(p[2], p[1], p[3], p[5], p[7])
def p_parameter_list_1(self, p):
"""parameter_list : """
p[0] = ast.ParameterList()
def p_parameter_list_2(self, p):
"""parameter_list : nonempty_parameter_list"""
p[0] = p[1]
def p_nonempty_parameter_list_1(self, p):
"""nonempty_parameter_list : parameter"""
p[0] = ast.ParameterList(p[1])
def p_nonempty_parameter_list_2(self, p):
"""nonempty_parameter_list : nonempty_parameter_list COMMA parameter"""
p[0] = p[1]
def p_parameter(self, p):
"""parameter : attribute_section typename NAME ordinal"""
p[0] = ast.Parameter(p[3], p[1], p[4], p[2],
filename=self.filename, lineno=p.lineno(3))
def p_typename(self, p):
"""typename : nonnullable_typename QSTN
| nonnullable_typename"""
if len(p) == 2:
p[0] = p[1]
p[0] = p[1] + "?"
def p_nonnullable_typename(self, p):
"""nonnullable_typename : basictypename
| array
| fixed_array
| associative_array
| interfacerequest"""
p[0] = p[1]
def p_basictypename(self, p):
"""basictypename : identifier
| ASSOCIATED identifier
| handletype"""
if len(p) == 2:
p[0] = p[1]
p[0] = "asso<" + p[2] + ">"
def p_handletype(self, p):
"""handletype : HANDLE
if len(p) == 2:
p[0] = p[1]
if p[3] not in ('data_pipe_consumer',
# Note: We don't enable tracking of line numbers for everything, so we
# can't use |p.lineno(3)|.
raise ParseError(self.filename, "Invalid handle type %r:" % p[3],
p[0] = "handle<" + p[3] + ">"
def p_array(self, p):
"""array : ARRAY LANGLE typename RANGLE"""
p[0] = p[3] + "[]"
def p_fixed_array(self, p):
"""fixed_array : ARRAY LANGLE typename COMMA INT_CONST_DEC RANGLE"""
value = int(p[5])
if value == 0 or value > _MAX_ARRAY_SIZE:
raise ParseError(self.filename, "Fixed array size %d invalid:" % value,
p[0] = p[3] + "[" + p[5] + "]"
def p_associative_array(self, p):
"""associative_array : MAP LANGLE identifier COMMA typename RANGLE"""
p[0] = p[5] + "{" + p[3] + "}"
def p_interfacerequest(self, p):
"""interfacerequest : identifier AMP
| ASSOCIATED identifier AMP"""
if len(p) == 3:
p[0] = p[1] + "&"
p[0] = "asso<" + p[2] + "&>"
def p_ordinal_1(self, p):
"""ordinal : """
p[0] = None
def p_ordinal_2(self, p):
"""ordinal : ORDINAL"""
value = int(p[1][1:])
if value > _MAX_ORDINAL_VALUE:
raise ParseError(self.filename, "Ordinal value %d too large:" % value,
p[0] = ast.Ordinal(value, filename=self.filename, lineno=p.lineno(1))
def p_enum_1(self, p):
"""enum : attribute_section ENUM NAME LBRACE enum_value_list \
| attribute_section ENUM NAME LBRACE nonempty_enum_value_list \
p[0] = ast.Enum(p[3], p[1], p[5], filename=self.filename,
def p_enum_2(self, p):
"""enum : attribute_section ENUM NAME SEMI"""
p[0] = ast.Enum(p[3], p[1], None, filename=self.filename,
def p_enum_value_list_1(self, p):
"""enum_value_list : """
p[0] = ast.EnumValueList()
def p_enum_value_list_2(self, p):
"""enum_value_list : nonempty_enum_value_list"""
p[0] = p[1]
def p_nonempty_enum_value_list_1(self, p):
"""nonempty_enum_value_list : enum_value"""
p[0] = ast.EnumValueList(p[1])
def p_nonempty_enum_value_list_2(self, p):
"""nonempty_enum_value_list : nonempty_enum_value_list COMMA enum_value"""
p[0] = p[1]
def p_enum_value(self, p):
"""enum_value : attribute_section NAME
| attribute_section NAME EQUALS int
| attribute_section NAME EQUALS identifier_wrapped"""
p[0] = ast.EnumValue(p[2], p[1], p[4] if len(p) == 5 else None,
filename=self.filename, lineno=p.lineno(2))
def p_const(self, p):
"""const : CONST typename NAME EQUALS constant SEMI"""
p[0] = ast.Const(p[3], p[2], p[5])
def p_constant(self, p):
"""constant : literal
| identifier_wrapped"""
p[0] = p[1]
def p_identifier_wrapped(self, p):
"""identifier_wrapped : identifier"""
p[0] = ('IDENTIFIER', p[1])
# TODO(vtl): Make this produce a "wrapped" identifier (probably as an
# |ast.Identifier|, to be added) and get rid of identifier_wrapped.
def p_identifier(self, p):
"""identifier : NAME
| NAME DOT identifier"""
p[0] = ''.join(p[1:])
def p_literal(self, p):
"""literal : int
| float
p[0] = p[1]
def p_int(self, p):
"""int : int_const
| PLUS int_const
| MINUS int_const"""
p[0] = ''.join(p[1:])
def p_int_const(self, p):
"""int_const : INT_CONST_DEC
p[0] = p[1]
def p_float(self, p):
"""float : FLOAT_CONST
p[0] = ''.join(p[1:])
def p_error(self, e):
if e is None:
# Unexpected EOF.
# TODO(vtl): Can we figure out what's missing?
raise ParseError(self.filename, "Unexpected end of file")
raise ParseError(self.filename, "Unexpected %r:" % e.value, lineno=e.lineno,
def _GetSnippet(self, lineno):
return self.source.split('\n')[lineno - 1]
def Parse(source, filename):
"""Parse source file to AST.
source: The source text as a str.
filename: The filename that |source| originates from.
The AST as a mojom.parse.ast.Mojom object.
lexer = Lexer(filename)
parser = Parser(lexer, source, filename)
yacc.yacc(module=parser, debug=0, write_tables=0)
tree = yacc.parse(source)
return tree