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rpcgen: add an XDR protocol parser
This adds a parser capable of handling the XDR protocol files. The parsing grammar requirements are detailed in https://www.rfc-editor.org/rfc/rfc4506#section-6.3 Reviewed-by: Michal Privoznik <mprivozn@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This commit is contained in:
Daniel P. Berrangé
parent
031efb691f
commit
ca3f025011
497
scripts/rpcgen/rpcgen/parser.py
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497
scripts/rpcgen/rpcgen/parser.py
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@ -0,0 +1,497 @@
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# SPDX-License-Identifier: LGPL-2.1-or-later
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from .lexer import (
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XDRLexer,
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XDRTokenPunctuation,
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XDRTokenIdentifier,
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XDRTokenCEscape,
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XDRTokenConstant,
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)
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from .ast import (
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XDRSpecification,
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XDRDefinitionConstant,
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XDRDefinitionTypedef,
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XDRDefinitionEnum,
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XDRDefinitionStruct,
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XDRDefinitionUnion,
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XDRDefinitionCEscape,
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XDRDeclarationScalar,
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XDRDeclarationPointer,
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XDRDeclarationFixedArray,
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XDRDeclarationVariableArray,
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XDRTypeVoid,
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XDRTypeChar,
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XDRTypeUnsignedChar,
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XDRTypeShort,
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XDRTypeUnsignedShort,
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XDRTypeInt,
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XDRTypeUnsignedInt,
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XDRTypeHyper,
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XDRTypeUnsignedHyper,
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XDRTypeFloat,
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XDRTypeDouble,
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XDRTypeBool,
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XDRTypeOpaque,
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XDRTypeString,
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XDRTypeCustom,
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XDREnumValue,
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XDREnumBody,
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XDRTypeEnum,
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XDRStructBody,
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XDRTypeStruct,
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XDRUnionCase,
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XDRUnionBody,
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XDRTypeUnion,
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)
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# We are parsing (approximately the following grammar
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# from RFC 4506 #6.3:
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#
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# declaration:
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# type-specifier identifier
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# | type-specifier identifier "[" value "]"
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# | type-specifier identifier "<" [ value ] ">"
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# | "opaque" identifier "[" value "]"
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# | "opaque" identifier "<" [ value ] ">"
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# | "string" identifier "<" [ value ] ">"
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# | type-specifier "*" identifier
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# | "void"
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#
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# value:
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# constant
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# | identifier
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#
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# constant:
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# decimal-constant | hexadecimal-constant | octal-constant
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#
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# type-specifier:
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# [ "unsigned" ] "int"
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# | [ "unsigned" ] "hyper"
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# | "float"
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# | "double"
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# | "quadruple" /* We're skipping this one */
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# | "bool"
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# | enum-type-spec
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# | struct-type-spec
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# | union-type-spec
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# | identifier
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#
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# enum-type-spec:
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# "enum" enum-body
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#
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# enum-body:
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# "{"
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# ( identifier "=" value )
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# ( "," identifier "=" value )*
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# "}"
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#
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# struct-type-spec:
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# "struct" struct-body
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#
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# struct-body:
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# "{"
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# ( declaration ";" )
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# ( declaration ";" )*
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# "}"
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#
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# union-type-spec:
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# "union" union-body
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#
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# union-body:
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# "switch" "(" declaration ")" "{"
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# case-spec
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# case-spec *
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# [ "default" ":" declaration ";" ]
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# "}"
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#
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# case-spec:
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# ( "case" value ":")
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# ( "case" value ":") *
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# declaration ";"
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#
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# constant-def:
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# "const" identifier "=" constant ";"
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#
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# type-def:
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# "typedef" declaration ";"
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# | "enum" identifier enum-body ";"
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# | "struct" identifier struct-body ";"
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# | "union" identifier union-body ";"
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#
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# definition:
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# type-def
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# | constant-def
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#
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# specification:
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# definition *
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#
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# Notable divergance:
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#
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# - In 'type-decl' we allow 'char' and 'short'
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# in signed and unsigned variants
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#
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# - In 'definition' we allow '%...' as escape C code
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# to passthrough to the header output
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#
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# - In 'enum-type-spec' we allow a bare enum name
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# instead of enum body
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#
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# - In 'struct-type-spec' we allow a bare struct name
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# instead of struct body
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#
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# - In 'union-type-spec' we allow a bare union name
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# instead of union body
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#
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class XDRParser:
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def __init__(self, fp):
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self.lexer = XDRLexer(fp)
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self.typedefs = {}
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def parse(self):
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spec = XDRSpecification()
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while True:
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definition = self.parse_definition()
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if definition is None:
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break
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spec.definitions.append(definition)
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return spec
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def parse_definition(self):
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token = self.lexer.next()
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if token is None:
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return None
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if type(token) == XDRTokenCEscape:
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return XDRDefinitionCEscape(token.value[1:])
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if type(token) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % token)
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defs = {
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"const": XDRDefinitionConstant,
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"typedef": XDRDefinitionTypedef,
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"enum": XDRDefinitionEnum,
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"struct": XDRDefinitionStruct,
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"union": XDRDefinitionUnion,
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}
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if token.value not in defs:
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raise Exception("Unexpected identifier %s" % token)
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funcname = "parse_definition_" + token.value
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func = getattr(self, funcname)
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assert func is not None
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definition = func()
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semi = self.lexer.next()
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if type(semi) != XDRTokenPunctuation or semi.value != ";":
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raise Exception("Expected ';', but got %s" % semi)
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return definition
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def parse_definition_const(self):
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ident = self.lexer.next()
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if type(ident) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % ident)
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assign = self.lexer.next()
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if type(assign) != XDRTokenPunctuation or assign.value != "=":
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raise Exception("Expected '=', but got %s" % assign)
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const = self.lexer.next()
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if type(const) not in [XDRTokenConstant, XDRTokenIdentifier]:
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raise Exception("Expected constant, but got %s" % const)
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return XDRDefinitionConstant(ident.value, const.value)
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def parse_definition_typedef(self):
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decl = self.parse_declaration()
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if decl.identifier in self.typedefs:
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raise Exception("Type '%s' already defined" % decl.identifier)
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definition = XDRDefinitionTypedef(decl)
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self.typedefs[decl.identifier] = definition
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return definition
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def parse_definition_enum(self):
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name = self.lexer.next()
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if type(name) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % name)
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body = self.parse_enum_body()
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if name.value in self.typedefs:
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raise Exception("Type '%s' already defined" % name.value)
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definition = XDRDefinitionEnum(name.value, body)
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self.typedefs[name.value] = definition
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return definition
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def parse_definition_struct(self):
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name = self.lexer.next()
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if type(name) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % name)
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body = self.parse_struct_body()
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if name.value in self.typedefs:
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raise Exception("Type '%s' already defined" % name.value)
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definition = XDRDefinitionStruct(name.value, body)
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self.typedefs[name.value] = definition
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return definition
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def parse_definition_union(self):
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name = self.lexer.next()
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if type(name) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % name)
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body = self.parse_union_body()
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if name.value in self.typedefs:
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raise Exception("Type '%s' already defined" % name.value)
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definition = XDRDefinitionUnion(name.value, body)
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self.typedefs[name.value] = definition
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return definition
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def parse_declaration(self):
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typ = self.parse_type()
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if type(typ) == XDRTypeVoid:
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return XDRDeclarationScalar(typ, None)
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ident = self.lexer.next()
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pointer = False
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if type(ident) == XDRTokenPunctuation:
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if ident.value != "*":
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raise Exception("Expected '*' or identifer, but got %s" % ident)
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if type(typ) == XDRTypeString or type(typ) == XDRTypeOpaque:
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raise Exception("Pointer invalid for 'string' and 'opaque' types")
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pointer = True
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ident = self.lexer.next()
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bracket = self.lexer.peek()
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if type(bracket) == XDRTokenPunctuation:
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if bracket.value == "[":
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_ = self.lexer.next()
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value = self.lexer.next()
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if type(value) not in [XDRTokenConstant, XDRTokenIdentifier]:
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raise Exception("Expected constant, but got %s" % value)
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close = self.lexer.next()
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if type(close) != XDRTokenPunctuation or close.value != "]":
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raise Exception("Expected ']', but got %s" % value)
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if type(typ) == XDRTypeString:
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raise Exception("Fixed array invalid for 'string' type")
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return XDRDeclarationFixedArray(typ, ident.value, value.value)
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elif bracket.value == "<":
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_ = self.lexer.next()
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maybeValue = self.lexer.peek()
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value = None
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if type(maybeValue) in [XDRTokenConstant, XDRTokenIdentifier]:
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value = self.lexer.next().value
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close = self.lexer.next()
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if type(close) != XDRTokenPunctuation or close.value != ">":
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raise Exception("Expected '>', but got %s" % close)
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return XDRDeclarationVariableArray(typ, ident.value, value)
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if pointer:
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return XDRDeclarationPointer(typ, ident.value)
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else:
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return XDRDeclarationScalar(typ, ident.value)
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def parse_type(self):
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typ = self.lexer.next()
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if type(typ) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % typ)
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if typ.value == "unsigned":
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typ = self.lexer.peek()
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if type(typ) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % typ)
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if typ.value == "char":
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_ = self.lexer.next()
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return XDRTypeUnsignedChar()
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elif typ.value == "short":
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_ = self.lexer.next()
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return XDRTypeUnsignedShort()
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elif typ.value == "int":
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_ = self.lexer.next()
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return XDRTypeUnsignedInt()
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elif typ.value == "hyper":
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_ = self.lexer.next()
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return XDRTypeUnsignedHyper()
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else:
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# Bare 'unsigned' isn't allowed by 'type-specifier'
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# grammer in RFC 1014, but rpcgen allows it
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return XDRTypeUnsignedInt()
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if typ.value == "void":
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return XDRTypeVoid()
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elif typ.value == "char":
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return XDRTypeChar()
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elif typ.value == "short":
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return XDRTypeShort()
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elif typ.value == "int":
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return XDRTypeInt()
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elif typ.value == "hyper":
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return XDRTypeHyper()
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elif typ.value == "float":
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return XDRTypeFloat()
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elif typ.value == "double":
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return XDRTypeDouble()
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elif typ.value == "bool":
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return XDRTypeBool()
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elif typ.value == "enum":
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return self.parse_type_enum()
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elif typ.value == "struct":
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return self.parse_type_struct()
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elif typ.value == "union":
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return self.parse_type_union()
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elif typ.value == "opaque":
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return XDRTypeOpaque()
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elif typ.value == "string":
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return XDRTypeString()
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else:
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return XDRTypeCustom(typ.value, self.typedefs.get(typ.value, None))
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def parse_enum_body(self):
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body = self.lexer.next()
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if type(body) != XDRTokenPunctuation or body.value != "{":
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raise Exception("Expected '{', but got %s" % body)
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values = []
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while True:
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ident = self.lexer.next()
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if type(ident) != XDRTokenIdentifier:
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raise Exception("Expected identifier, but got %s" % ident)
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equal = self.lexer.next()
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if type(equal) != XDRTokenPunctuation or equal.value != "=":
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raise Exception("Expected '=', but got %s" % ident)
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value = self.lexer.next()
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if type(value) != XDRTokenConstant:
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raise Exception("Expected constant, but got %s" % ident)
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separator = self.lexer.next()
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if type(separator) != XDRTokenPunctuation and separator.value not in [
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"}",
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",",
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]:
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raise Exception("Expected '}' or ',', but got %s" % separator)
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values.append(XDREnumValue(ident.value, value.value))
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if separator.value == "}":
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break
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return XDREnumBody(values)
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def parse_type_enum(self):
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body = self.parse_enum_body()
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return XDRTypeEnum(body)
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def parse_struct_body(self):
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body = self.lexer.next()
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if type(body) != XDRTokenPunctuation or body.value != "{":
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raise Exception("Expected '{', but got %s" % body)
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fields = []
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while True:
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field = self.parse_declaration()
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fields.append(field)
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separator = self.lexer.next()
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if type(separator) != XDRTokenPunctuation and separator.value != ";":
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raise Exception("Expected ';', but got %s" % separator)
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end = self.lexer.peek()
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if type(end) == XDRTokenPunctuation and end.value == "}":
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break
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# discard the '}' we peeked at to end the loop
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_ = self.lexer.next()
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return XDRStructBody(fields)
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def parse_type_struct(self):
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body = self.parse_struct_body()
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return XDRTypeStruct(body)
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def parse_union_body(self):
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ident = self.lexer.next()
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if type(ident) != XDRTokenIdentifier or ident.value != "switch":
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raise Exception("Expected 'switch', but got %s" % ident)
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bracket = self.lexer.next()
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if type(bracket) != XDRTokenPunctuation or bracket.value != "(":
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raise Exception("Expected '(', but got %s" % bracket)
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discriminator = self.parse_declaration()
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bracket = self.lexer.next()
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if type(bracket) != XDRTokenPunctuation or bracket.value != ")":
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raise Exception("Expected ')', but got %s" % bracket)
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bracket = self.lexer.next()
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if type(bracket) != XDRTokenPunctuation or bracket.value != "{":
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raise Exception("Expected '{', but got %s" % bracket)
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default = None
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cases = []
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while True:
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ident = self.lexer.next()
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if type(ident) != XDRTokenIdentifier or ident.value not in [
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"default",
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"case",
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]:
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raise Exception("Expected 'default' or 'case', but got %s" % ident)
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value = None
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if ident.value == "case":
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value = self.lexer.next()
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if type(value) not in [XDRTokenConstant, XDRTokenIdentifier]:
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raise Exception("Expected constant, but got %s" % value)
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sep = self.lexer.next()
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if type(sep) != XDRTokenPunctuation or sep.value != ":":
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raise Exception("Expected ':', but got %s" % value)
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decl = self.parse_declaration()
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case = XDRUnionCase(value.value, decl)
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cases.append(case)
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else:
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if default is not None:
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raise Exception("Duplicate 'default' clause")
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sep = self.lexer.next()
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if type(sep) != XDRTokenPunctuation or sep.value != ":":
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raise Exception("Expected ':', but got %s" % value)
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default = self.parse_declaration()
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separator = self.lexer.next()
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if type(separator) != XDRTokenPunctuation and separator.value != ";":
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raise Exception("Expected ';', but got %s" % bracket)
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end = self.lexer.peek()
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if type(end) == XDRTokenPunctuation and end.value == "}":
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break
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# discard the '}' we peeked at to end the loop
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_ = self.lexer.next()
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return XDRUnionBody(discriminator, cases, default)
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def parse_type_union(self):
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body = self.parse_union_body()
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||||
return XDRTypeUnion(body)
|
||||
@ -1,3 +1,4 @@
|
||||
rpcgen_tests = files([
|
||||
'test_lexer.py',
|
||||
'test_parser.py',
|
||||
])
|
||||
|
||||
91
scripts/rpcgen/tests/test_parser.py
Normal file
91
scripts/rpcgen/tests/test_parser.py
Normal file
@ -0,0 +1,91 @@
|
||||
# SPDX-License-Identifier: LGPL-2.1-or-later
|
||||
|
||||
from pathlib import Path
|
||||
|
||||
from rpcgen.ast import (
|
||||
XDRSpecification,
|
||||
XDRDefinitionConstant,
|
||||
XDRDefinitionEnum,
|
||||
XDRDefinitionUnion,
|
||||
XDRDefinitionStruct,
|
||||
XDRDeclarationScalar,
|
||||
XDRDeclarationVariableArray,
|
||||
XDREnumValue,
|
||||
XDREnumBody,
|
||||
XDRStructBody,
|
||||
XDRUnionCase,
|
||||
XDRUnionBody,
|
||||
XDRTypeCustom,
|
||||
XDRTypeVoid,
|
||||
XDRTypeString,
|
||||
XDRTypeOpaque,
|
||||
)
|
||||
from rpcgen.parser import XDRParser
|
||||
|
||||
|
||||
def test_parser():
|
||||
p = Path(Path(__file__).parent, "simple.x")
|
||||
with p.open("r") as fp:
|
||||
parser = XDRParser(fp)
|
||||
|
||||
got = parser.parse()
|
||||
|
||||
enum = XDRDefinitionEnum(
|
||||
"filekind",
|
||||
XDREnumBody(
|
||||
[
|
||||
XDREnumValue("TEXT", "0"),
|
||||
XDREnumValue("DATA", "1"),
|
||||
XDREnumValue("EXEC", "2"),
|
||||
],
|
||||
),
|
||||
)
|
||||
|
||||
union = XDRDefinitionUnion(
|
||||
"filetype",
|
||||
XDRUnionBody(
|
||||
XDRDeclarationScalar(XDRTypeCustom("filekind", enum), "kind"),
|
||||
[
|
||||
XDRUnionCase("TEXT", XDRDeclarationScalar(XDRTypeVoid(), None)),
|
||||
XDRUnionCase(
|
||||
"DATA",
|
||||
XDRDeclarationVariableArray(
|
||||
XDRTypeString(), "creator", "MAXNAMELEN"
|
||||
),
|
||||
),
|
||||
XDRUnionCase(
|
||||
"EXEC",
|
||||
XDRDeclarationVariableArray(
|
||||
XDRTypeString(), "interpretor", "MAXNAMELEN"
|
||||
),
|
||||
),
|
||||
],
|
||||
None,
|
||||
),
|
||||
)
|
||||
|
||||
struct = XDRDefinitionStruct(
|
||||
"file",
|
||||
XDRStructBody(
|
||||
[
|
||||
XDRDeclarationVariableArray(XDRTypeString(), "filename", "MAXNAMELEN"),
|
||||
XDRDeclarationScalar(XDRTypeCustom("filetype", union), "type"),
|
||||
XDRDeclarationVariableArray(XDRTypeString(), "owner", "MAXUSERNAME"),
|
||||
XDRDeclarationVariableArray(XDRTypeOpaque(), "data", "MAXFILELEN"),
|
||||
]
|
||||
),
|
||||
)
|
||||
|
||||
want = XDRSpecification()
|
||||
want.definitions.extend(
|
||||
[
|
||||
XDRDefinitionConstant("MAXUSERNAME", "32"),
|
||||
XDRDefinitionConstant("MAXFILELEN", "65535"),
|
||||
XDRDefinitionConstant("MAXNAMELEN", "255"),
|
||||
enum,
|
||||
union,
|
||||
struct,
|
||||
]
|
||||
)
|
||||
|
||||
assert str(got) == str(want)
|
||||
Loading…
Reference in New Issue
Block a user