8000 Second attempt at refactoring parser. · PyMySQL/PyMySQL@25df7f4 · GitHub
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groutrmethane
groutr
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methane
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Second attempt at refactoring parser.
14 test fail (I think mostly due to MariaDB syntax issues).
1 parent 68e5800 commit 25df7f4

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lines changed

‎pymysql/connections.py

Lines changed: 2 additions & 223 deletions
Original file line numberDiff line numberDiff line change
@@ -16,13 +16,14 @@
1616
import traceback
1717
import warnings
1818

19-
from .charset import MBLENGTH, charset_by_name, charset_by_id
19+
from .charset import charset_by_name, charset_by_id
2020
from .constants import CLIENT, COMMAND, CR, FIELD_TYPE, SERVER_STATUS
2121
from . import converters
2222
from .cursors import Cursor
2323
from .optionfile import Parser
2424
from .util import byte2int, int2byte
2525
from . import err
26+
from .parser import MysqlPacket, FieldDescriptorPacket
2627

2728
try:
2829
import ssl
@@ -214,228 +215,6 @@ def lenenc_int(i):
214215
else:
215216
raise ValueError("Encoding %x is larger than %x - no representation in LengthEncodedInteger" % (i, (1 << 64)))
216217

217-
class MysqlPacket(object):
218-
"""Representation of a MySQL response packet.
219-
220-
Provides an interface for reading/parsing the packet results.
221-
"""
222-
__slots__ = ('_position', '_data')
223-
224-
def __init__(self, data, encoding):
225-
self._position = 0
226-
self._data = data
227-
228-
def get_all_data(self):
229-
return self._data
230-
231-
def read(self, size):
232-
"""Read the first 'size' bytes in packet and advance cursor past them."""
233-
result = self._data[self._position:(self._position+size)]
234-
if len(result) != size:
235-
error = ('Result length not requested length:\n'
236-
'Expected=%s. Actual=%s. Position: %s. Data Length: %s'
237-
% (size, len(result), self._position, len(self._data)))
238-
if DEBUG:
239-
print(error)
240-
self.dump()
241-
raise AssertionError(error)
242-
self._position += size
243-
return result
244-
245-
def read_all(self):
246-
"""Read all remaining data in the packet.
247-
248-
(Subsequent read() will return errors.)
249-
"""
250-
result = self._data[self._position:]
251-
self._position = None # ensure no subsequent read()
252-
return result
253-
254-
def advance(self, length):
255-
"""Advance the cursor in data buffer 'length' bytes."""
256-
new_position = self._position + length
257-
if new_position < 0 or new_position > len(self._data):
258-
raise Exception('Invalid advance amount (%s) for cursor. '
259-
'Position=%s' % (length, new_position))
260-
self._position = new_position
261-
262-
def rewind(self, position=0):
263-
"""Set the position of the data buffer cursor to 'position'."""
264-
if position < 0 or position > len(self._data):
265-
raise Exception("Invalid position to rewind cursor to: %s." % position)
266-
self._position = position
267-
268-
def get_bytes(self, position, length=1):
269-
"""Get 'length' bytes starting at 'position'.
270-
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Position is start of payload (first four packet header bytes are not
272-
included) starting at index '0'.
273-
274-
No error checking is done. If requesting outside end of buffer
275-
an empty string (or string shorter than 'length') may be returned!
276-
"""
277-
return self._data[position:(position+length)]
278-
279-
if PY2:
280-
def read_uint8(self):
281-
result = ord(self._data[self._position])
282-
self._position += 1
283-
return result
284-
else:
285-
def read_uint8(self):
286-
result = self._data[self._position]
287-
self._position += 1
288-
return result
289-
290-
def read_uint16(self):
291-
result = struct.unpack_from('<H', self._data, self._position)[0]
292-
self._position += 2
293-
return result
294-
295-
def read_uint24(self):
296-
low, high = struct.unpack_from('<HB', self._data, self._position)
297-
self._position += 3
298-
return low + (high << 16)
299-
300-
def read_uint32(self):
301-
result = struct.unpack_from('<I', self._data, self._position)[0]
302-
self._position += 4
303-
return result
304-
305-
def read_uint64(self):
306-
result = struct.unpack_from('<Q', self._data, self._position)[0]
307-
self._position += 8
308-
return result
309-
310-
def read_string(self):
311-
end_pos = self._data.find(b'\0', self._position)
312-
if end_pos < 0:
313-
return None
314-
result = self._data[self._position:end_pos]
315-
self._position = end_pos + 1
316-
return result
317-
318-
def read_length_encoded_integer(self):
319-
"""Read a 'Length Coded Binary' number from the data buffer.
320-
321-
Length coded numbers can be anywhere from 1 to 9 bytes depending
322-
on the value of the first byte.
323-
"""
324-
c = self.read_uint8()
325-
if c == NULL_COLUMN:
326-
return None
327-
if c < UNSIGNED_CHAR_COLUMN:
328-
return c
329-
elif c == UNSIGNED_SHORT_COLUMN:
330-
return self.read_uint16()
331-
elif c == UNSIGNED_INT24_COLUMN:
332-
return self.read_uint24()
333-
elif c == UNSIGNED_INT64_COLUMN:
334-
return self.read_uint64()
335-
336-
def read_length_coded_string(self):
337-
"""Read a 'Length Coded String' from the data buffer.
338-
339-
A 'Length Coded String' consists first of a length coded
340-
(unsigned, positive) integer represented in 1-9 bytes followed by
341-
that many bytes of binary data. (For example "cat" would be "3cat".)
342-
"""
343-
length = self.read_length_encoded_integer()
344-
if length is None:
345-
return None
346-
return self.read(length)
347-
348-
def read_struct(self, fmt):
349-
s = struct.Struct(fmt)
350-
result = s.unpack_from(self._data, self._position)
351-
self._position += s.size
352-
return result
353-
354-
def is_ok_packet(self):
355-
# https://dev.mysql.com/doc/internals/en/packet-OK_Packet.html
356-
return self._data[0:1] == b'\0' and len(self._data) >= 7
357-
358-
def is_eof_packet(self):
359-
# http://dev.mysql.com/doc/internals/en/generic-response-packets.html#packet-EOF_Packet
360-
# Caution: \xFE may be LengthEncodedInteger.
361-
# If \xFE is LengthEncodedInteger header, 8bytes followed.
362-
return self._data[0:1] == b'\xfe' and len(self._data) < 9
363-
364-
def is_auth_switch_request(self):
365-
# http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::AuthSwitchRequest
366-
return self._data[0:1] == b'\xfe'
367-
368-
def is_resultset_packet(self):
369-
field_count = ord(self._data[0:1])
370-
return 1 <= field_count <= 250
371-
372-
def is_load_local_packet(self):
373-
return self._data[0:1] == b'\xfb'
374-
375-
def is_error_packet(self):
376-
return self._data[0:1] == b'\xff'
377-
378-
def check_error(self):
379-
if self.is_error_packet():
380-
self.rewind()
381-
self.advance(1) # field_count == error (we already know that)
382-
errno = self.read_uint16()
383-
if DEBUG: print("errno =", errno)
384-
err.raise_mysql_exception(self._data)
385-
386-
def dump(self):
387-
dump_packet(self._data)
388-
389-
390-
class FieldDescriptorPacket(MysqlPacket):
391-
"""A MysqlPacket that represents a specific column's metadata in the result.
392-
393-
Parsing is automatically done and the results are exported via public
394-
attributes on the class such as: db, table_name, name, length, type_code.
395-
"""
396-
397-
def __init__(self, data, encoding):
398-
MysqlPacket.__init__(self, data, encoding)
399-
self._parse_field_descriptor(encoding)
400-
401-
def _parse_field_descriptor(self, encoding):
402-
"""Parse the 'Field Descriptor' (Metadata) packet.
403-
404-
This is compatible with MySQL 4.1+ (not compatible with MySQL 4.0).
405-
"""
406-
self.catalog = self.read_length_coded_string()
407-
self.db = self.read_length_coded_string()
408-
self.table_name = self.read_length_coded_string().decode(encoding)
409-
self.org_table = self.read_length_coded_string().decode(encoding)
410-
self.name = self.read_length_coded_string().decode(encoding)
411-
self.org_name = self.read_length_coded_string().decode(encoding)
412-
self.charsetnr, self.length, self.type_code, self.flags, self.scale = (
413-
self.read_struct('<xHIBHBxx'))
414-
# 'default' is a length coded binary and is still in the buffer?
415-
# not used for normal result sets...
416-
417-
def description(self):
418-
"""Provides a 7-item tuple compatible with the Python PEP249 DB Spec."""
419-
return (
420-
self.name,
421-
self.type_code,
422-
None, # TODO: display_length; should this be self.length?
423-
self.get_column_length(), # 'internal_size'
424-
self.get_column_length(), # 'precision' # TODO: why!?!?
425-
self.scale,
426-
self.flags % 2 == 0)
427-
428-
def get_column_length(self):
429-
if self.type_code == FIELD_TYPE.VAR_STRING:
430-
mblen = MBLENGTH.get(self.charsetnr, 1)
431-
return self.length // mblen
432-
return self.length
433-
434-
def __str__(self):
435-
return ('%s %r.%r.%r, type=%s, flags=%x'
436-
% (self.__class__, self.db, self.table_name, self.name,
437-
self.type_code, self.flags))
438-
439218

440219
class OKPacketWrapper(object):
441220
"""

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