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|
import ruyaml
from ruyaml.composer import Composer
from ruyaml.constructor import Constructor
from ruyaml.resolver import Resolver
class CanonicalError(ruyaml.YAMLError):
pass
class CanonicalScanner:
def __init__(self, data):
try:
if isinstance(data, bytes):
data = data.decode('utf-8')
except UnicodeDecodeError:
raise CanonicalError('utf-8 stream is expected')
self.data = data + '\0'
self.index = 0
self.tokens = []
self.scanned = False
def check_token(self, *choices):
if not self.scanned:
self.scan()
if self.tokens:
if not choices:
return True
for choice in choices:
if isinstance(self.tokens[0], choice):
return True
return False
def peek_token(self):
if not self.scanned:
self.scan()
if self.tokens:
return self.tokens[0]
def get_token(self, choice=None):
if not self.scanned:
self.scan()
token = self.tokens.pop(0)
if choice and not isinstance(token, choice):
raise CanonicalError('unexpected token ' + repr(token))
return token
def get_token_value(self):
token = self.get_token()
return token.value
def scan(self):
self.tokens.append(ruyaml.StreamStartToken(None, None))
while True:
self.find_token()
ch = self.data[self.index]
if ch == '\0':
self.tokens.append(ruyaml.StreamEndToken(None, None))
break
elif ch == '%':
self.tokens.append(self.scan_directive())
elif ch == '-' and self.data[self.index : self.index + 3] == '---':
self.index += 3
self.tokens.append(ruyaml.DocumentStartToken(None, None))
elif ch == '[':
self.index += 1
self.tokens.append(ruyaml.FlowSequenceStartToken(None, None))
elif ch == '{':
self.index += 1
self.tokens.append(ruyaml.FlowMappingStartToken(None, None))
elif ch == ']':
self.index += 1
self.tokens.append(ruyaml.FlowSequenceEndToken(None, None))
elif ch == '}':
self.index += 1
self.tokens.append(ruyaml.FlowMappingEndToken(None, None))
elif ch == '?':
self.index += 1
self.tokens.append(ruyaml.KeyToken(None, None))
elif ch == ':':
self.index += 1
self.tokens.append(ruyaml.ValueToken(None, None))
elif ch == ',':
self.index += 1
self.tokens.append(ruyaml.FlowEntryToken(None, None))
elif ch == '*' or ch == '&':
self.tokens.append(self.scan_alias())
elif ch == '!':
self.tokens.append(self.scan_tag())
elif ch == '"':
self.tokens.append(self.scan_scalar())
else:
raise CanonicalError('invalid token')
self.scanned = True
DIRECTIVE = '%YAML 1.1'
def scan_directive(self):
if (
self.data[self.index : self.index + len(self.DIRECTIVE)] == self.DIRECTIVE
and self.data[self.index + len(self.DIRECTIVE)] in ' \n\0'
):
self.index += len(self.DIRECTIVE)
return ruyaml.DirectiveToken('YAML', (1, 1), None, None)
else:
raise CanonicalError('invalid directive')
def scan_alias(self):
if self.data[self.index] == '*':
TokenClass = ruyaml.AliasToken
else:
TokenClass = ruyaml.AnchorToken
self.index += 1
start = self.index
while self.data[self.index] not in ', \n\0':
self.index += 1
value = self.data[start : self.index]
return TokenClass(value, None, None)
def scan_tag(self):
self.index += 1
start = self.index
while self.data[self.index] not in ' \n\0':
self.index += 1
value = self.data[start : self.index]
if not value:
value = '!'
elif value[0] == '!':
value = 'tag:yaml.org,2002:' + value[1:]
elif value[0] == '<' and value[-1] == '>':
value = value[1:-1]
else:
value = '!' + value
return ruyaml.TagToken(value, None, None)
QUOTE_CODES = {'x': 2, 'u': 4, 'U': 8}
QUOTE_REPLACES = {
'\\': '\\',
'"': '"',
' ': ' ',
'a': '\x07',
'b': '\x08',
'e': '\x1B',
'f': '\x0C',
'n': '\x0A',
'r': '\x0D',
't': '\x09',
'v': '\x0B',
'N': '\u0085',
'L': '\u2028',
'P': '\u2029',
'_': '_',
'0': '\x00',
}
def scan_scalar(self):
self.index += 1
chunks = []
start = self.index
ignore_spaces = False
while self.data[self.index] != '"':
if self.data[self.index] == '\\':
ignore_spaces = False
chunks.append(self.data[start : self.index])
self.index += 1
ch = self.data[self.index]
self.index += 1
if ch == '\n':
ignore_spaces = True
elif ch in self.QUOTE_CODES:
length = self.QUOTE_CODES[ch]
code = int(self.data[self.index : self.index + length], 16)
chunks.append(chr(code))
self.index += length
else:
if ch not in self.QUOTE_REPLACES:
raise CanonicalError('invalid escape code')
chunks.append(self.QUOTE_REPLACES[ch])
start = self.index
elif self.data[self.index] == '\n':
chunks.append(self.data[start : self.index])
chunks.append(' ')
self.index += 1
start = self.index
ignore_spaces = True
elif ignore_spaces and self.data[self.index] == ' ':
self.index += 1
start = self.index
else:
ignore_spaces = False
self.index += 1
chunks.append(self.data[start : self.index])
self.index += 1
return ruyaml.ScalarToken("".join(chunks), False, None, None)
def find_token(self):
found = False
while not found:
while self.data[self.index] in ' \t':
self.index += 1
if self.data[self.index] == '#':
while self.data[self.index] != '\n':
self.index += 1
if self.data[self.index] == '\n':
self.index += 1
else:
found = True
class CanonicalParser:
def __init__(self):
self.events = []
self.parsed = False
def dispose(self):
pass
# stream: STREAM-START document* STREAM-END
def parse_stream(self):
self.get_token(ruyaml.StreamStartToken)
self.events.append(ruyaml.StreamStartEvent(None, None))
while not self.check_token(ruyaml.StreamEndToken):
if self.check_token(ruyaml.DirectiveToken, ruyaml.DocumentStartToken):
self.parse_document()
else:
raise CanonicalError(
'document is expected, got ' + repr(self.tokens[0])
)
self.get_token(ruyaml.StreamEndToken)
self.events.append(ruyaml.StreamEndEvent(None, None))
# document: DIRECTIVE? DOCUMENT-START node
def parse_document(self):
# node = None
if self.check_token(ruyaml.DirectiveToken):
self.get_token(ruyaml.DirectiveToken)
self.get_token(ruyaml.DocumentStartToken)
self.events.append(ruyaml.DocumentStartEvent(None, None))
self.parse_node()
self.events.append(ruyaml.DocumentEndEvent(None, None))
# node: ALIAS | ANCHOR? TAG? (SCALAR|sequence|mapping)
def parse_node(self):
if self.check_token(ruyaml.AliasToken):
self.events.append(ruyaml.AliasEvent(self.get_token_value(), None, None))
else:
anchor = None
if self.check_token(ruyaml.AnchorToken):
anchor = self.get_token_value()
tag = None
if self.check_token(ruyaml.TagToken):
tag = self.get_token_value()
if self.check_token(ruyaml.ScalarToken):
self.events.append(
ruyaml.ScalarEvent(
anchor, tag, (False, False), self.get_token_value(), None, None
)
)
elif self.check_token(ruyaml.FlowSequenceStartToken):
self.events.append(ruyaml.SequenceStartEvent(anchor, tag, None, None))
self.parse_sequence()
elif self.check_token(ruyaml.FlowMappingStartToken):
self.events.append(ruyaml.MappingStartEvent(anchor, tag, None, None))
self.parse_mapping()
else:
raise CanonicalError(
"SCALAR, '[', or '{' is expected, got " + repr(self.tokens[0])
)
# sequence: SEQUENCE-START (node (ENTRY node)*)? ENTRY? SEQUENCE-END
def parse_sequence(self):
self.get_token(ruyaml.FlowSequenceStartToken)
if not self.check_token(ruyaml.FlowSequenceEndToken):
self.parse_node()
while not self.check_token(ruyaml.FlowSequenceEndToken):
self.get_token(ruyaml.FlowEntryToken)
if not self.check_token(ruyaml.FlowSequenceEndToken):
self.parse_node()
self.get_token(ruyaml.FlowSequenceEndToken)
self.events.append(ruyaml.SequenceEndEvent(None, None))
# mapping: MAPPING-START (map_entry (ENTRY map_entry)*)? ENTRY? MAPPING-END
def parse_mapping(self):
self.get_token(ruyaml.FlowMappingStartToken)
if not self.check_token(ruyaml.FlowMappingEndToken):
self.parse_map_entry()
while not self.check_token(ruyaml.FlowMappingEndToken):
self.get_token(ruyaml.FlowEntryToken)
if not self.check_token(ruyaml.FlowMappingEndToken):
self.parse_map_entry()
self.get_token(ruyaml.FlowMappingEndToken)
self.events.append(ruyaml.MappingEndEvent(None, None))
# map_entry: KEY node VALUE node
def parse_map_entry(self):
self.get_token(ruyaml.KeyToken)
self.parse_node()
self.get_token(ruyaml.ValueToken)
self.parse_node()
def parse(self):
self.parse_stream()
self.parsed = True
def get_event(self):
if not self.parsed:
self.parse()
return self.events.pop(0)
def check_event(self, *choices):
if not self.parsed:
self.parse()
if self.events:
if not choices:
return True
for choice in choices:
if isinstance(self.events[0], choice):
return True
return False
def peek_event(self):
if not self.parsed:
self.parse()
return self.events[0]
class CanonicalLoader(
CanonicalScanner, CanonicalParser, Composer, Constructor, Resolver
):
def __init__(self, stream):
if hasattr(stream, 'read'):
stream = stream.read()
CanonicalScanner.__init__(self, stream)
CanonicalParser.__init__(self)
Composer.__init__(self)
Constructor.__init__(self)
Resolver.__init__(self)
ruyaml.CanonicalLoader = CanonicalLoader
def canonical_scan(stream):
yaml = ruyaml.YAML()
yaml.scanner = CanonicalScanner
return yaml.scan(stream)
ruyaml.canonical_scan = canonical_scan
def canonical_parse(stream):
yaml = ruyaml.YAML()
return yaml.parse(stream, Loader=CanonicalLoader)
ruyaml.canonical_parse = canonical_parse
def canonical_compose(stream):
yaml = ruyaml.YAML()
return yaml.compose(stream, Loader=CanonicalLoader)
ruyaml.canonical_compose = canonical_compose
def canonical_compose_all(stream):
yaml = ruyaml.YAML()
return yaml.compose_all(stream, Loader=CanonicalLoader)
ruyaml.canonical_compose_all = canonical_compose_all
def canonical_load(stream):
yaml = ruyaml.YAML()
return yaml.load(stream, Loader=CanonicalLoader)
ruyaml.canonical_load = canonical_load
def canonical_load_all(stream):
yaml = ruyaml.YAML(typ='safe', pure=True)
yaml.Loader = CanonicalLoader
return yaml.load_all(stream)
ruyaml.canonical_load_all = canonical_load_all
|
