# Copyright (C) 2016-present the asyncpg authors and contributors
# <see AUTHORS file>
#
# This module is part of asyncpg and is released under
# the Apache 2.0 License: http://www.apache.org/licenses/LICENSE-2.0
from libc.string cimport memcpy
import collections
class BufferError(Exception):
pass
@cython.no_gc_clear
@cython.final
@cython.freelist(_BUFFER_FREELIST_SIZE)
cdef class WriteBuffer:
def __cinit__(self):
self._smallbuf_inuse = True
self._buf = self._smallbuf
self._size = _BUFFER_INITIAL_SIZE
self._length = 0
self._message_mode = 0
def __dealloc__(self):
if self._buf is not NULL and not self._smallbuf_inuse:
cpython.PyMem_Free(self._buf)
self._buf = NULL
self._size = 0
if self._view_count:
raise BufferError(
'Deallocating buffer with attached memoryviews')
def __getbuffer__(self, Py_buffer *buffer, int flags):
self._view_count += 1
cpython.PyBuffer_FillInfo(
buffer, self, self._buf, self._length,
1, # read-only
flags)
def __releasebuffer__(self, Py_buffer *buffer):
self._view_count -= 1
cdef inline _check_readonly(self):
if self._view_count:
raise BufferError('the buffer is in read-only mode')
cdef inline _ensure_alloced(self, ssize_t extra_length):
cdef ssize_t new_size = extra_length + self._length
if new_size > self._size:
self._reallocate(new_size)
cdef _reallocate(self, ssize_t new_size):
cdef char *new_buf
if new_size < _BUFFER_MAX_GROW:
new_size = _BUFFER_MAX_GROW
else:
# Add a little extra
new_size += _BUFFER_INITIAL_SIZE
if self._smallbuf_inuse:
new_buf = <char*>cpython.PyMem_Malloc(
sizeof(char) * <size_t>new_size)
if new_buf is NULL:
self._buf = NULL
self._size = 0
self._length = 0
raise MemoryError
memcpy(new_buf, self._buf, <size_t>self._size)
self._size = new_size
self._buf = new_buf
self._smallbuf_inuse = False
else:
new_buf = <char*>cpython.PyMem_Realloc(
<void*>self._buf, <size_t>new_size)
if new_buf is NULL:
cpython.PyMem_Free(self._buf)
self._buf = NULL
self._size = 0
self._length = 0
raise MemoryError
self._buf = new_buf
self._size = new_size
cdef inline start_message(self, char type):
if self._length != 0:
raise BufferError(
'cannot start_message for a non-empty buffer')
self._ensure_alloced(5)
self._message_mode = 1
self._buf[0] = type
self._length = 5
cdef inline end_message(self):
# "length-1" to exclude the message type byte
cdef ssize_t mlen = self._length - 1
self._check_readonly()
if not self._message_mode:
raise BufferError(
'end_message can only be called with start_message')
if self._length < 5:
raise BufferError('end_message: buffer is too small')
if mlen > _MAXINT32:
raise BufferError('end_message: message is too large')
hton.pack_int32(&self._buf[1], <int32_t>mlen)
return self
cdef inline reset(self):
self._length = 0
self._message_mode = 0
cdef write_buffer(self, WriteBuffer buf):
self._check_readonly()
if not buf._length:
return
self._ensure_alloced(buf._length)
memcpy(self._buf + self._length,
<void*>buf._buf,
<size_t>buf._length)
self._length += buf._length
cdef write_byte(self, char b):
self._check_readonly()
self._ensure_alloced(1)
self._buf[self._length] = b
self._length += 1
cdef write_bytes(self, bytes data):
cdef char* buf
cdef ssize_t len
cpython.PyBytes_AsStringAndSize(data, &buf, &len)
self.write_cstr(buf, len)
cdef write_bytestring(self, bytes string):
cdef char* buf
cdef ssize_t len
cpython.PyBytes_AsStringAndSize(string, &buf, &len)
# PyBytes_AsStringAndSize returns a null-terminated buffer,
# but the null byte is not counted in len. hence the + 1
self.write_cstr(buf, len + 1)
cdef write_str(self, str string, str encoding):
self.write_bytestring(string.encode(encoding))
cdef write_len_prefixed_buffer(self, WriteBuffer buf):
# Write a length-prefixed (not NULL-terminated) bytes sequence.
self.write_int32(<int32_t>buf.len())
self.write_buffer(buf)
cdef write_len_prefixed_bytes(self, bytes data):
# Write a length-prefixed (not NULL-terminated) bytes sequence.
cdef:
char *buf
ssize_t size
cpython.PyBytes_AsStringAndSize(data, &buf, &size)
if size > _MAXINT32:
raise BufferError('string is too large')
# `size` does not account for the NULL at the end.
self.write_int32(<int32_t>size)
self.write_cstr(buf, size)
cdef write_frbuf(self, FRBuffer *buf):
cdef:
ssize_t buf_len = buf.len
if buf_len > 0:
self.write_cstr(frb_read_all(buf), buf_len)
cdef write_cstr(self, const char *data, ssize_t len):
self._check_readonly()
self._ensure_alloced(len)
memcpy(self._buf + self._length, <void*>data, <size_t>len)
self._length += len
cdef write_int16(self, int16_t i):
self._check_readonly()
self._ensure_alloced(2)
hton.pack_int16(&self._buf[self._length], i)
self._length += 2
cdef write_int32(self, int32_t i):
self._check_readonly()
self._ensure_alloced(4)
hton.pack_int32(&self._buf[self._length], i)
self._length += 4
cdef write_int64(self, int64_t i):
self._check_readonly()
self._ensure_alloced(8)
hton.pack_int64(&self._buf[self._length], i)
self._length += 8
cdef write_float(self, float f):
self._check_readonly()
self._ensure_alloced(4)
hton.pack_float(&self._buf[self._length], f)
self._length += 4
cdef write_double(self, double d):
self._check_readonly()
self._ensure_alloced(8)
hton.pack_double(&self._buf[self._length], d)
self._length += 8
@staticmethod
cdef WriteBuffer new_message(char type):
cdef WriteBuffer buf
buf = WriteBuffer.__new__(WriteBuffer)
buf.start_message(type)
return buf
@staticmethod
cdef WriteBuffer new():
cdef WriteBuffer buf
buf = WriteBuffer.__new__(WriteBuffer)
return buf
@cython.no_gc_clear
@cython.final
@cython.freelist(_BUFFER_FREELIST_SIZE)
cdef class ReadBuffer:
def __cinit__(self):
self._bufs = collections.deque()
self._bufs_append = self._bufs.append
self._bufs_popleft = self._bufs.popleft
self._bufs_len = 0
self._buf0 = None
self._buf0_prev = None
self._pos0 = 0
self._len0 = 0
self._length = 0
self._current_message_type = 0
self._current_message_len = 0
self._current_message_len_unread = 0
self._current_message_ready = 0
cdef feed_data(self, data):
cdef:
ssize_t dlen
bytes data_bytes
if not cpython.PyBytes_CheckExact(data):
if cpythonx.PyByteArray_CheckExact(data):
# ProactorEventLoop in Python 3.10+ seems to be sending
# bytearray objects instead of bytes. Handle this here
# to avoid duplicating this check in every data_received().
data = bytes(data)
else:
raise BufferError(
'feed_data: a bytes or bytearray object expected')
# Uncomment the below code to test code paths that
# read single int/str/bytes sequences are split over
# multiple received buffers.
#
# ll = 107
# if len(data) > ll:
# self.feed_data(data[:ll])
# self.feed_data(data[ll:])
# return
data_bytes = <bytes>data
dlen = cpython.Py_SIZE(data_bytes)
if dlen == 0:
# EOF?
return
self._bufs_append(data_bytes)
self._length += dlen
if self._bufs_len == 0:
# First buffer
self._len0 = dlen
self._buf0 = data_bytes
self._bufs_len += 1
cdef inline _ensure_first_buf(self):
if PG_DEBUG:
if self._len0 == 0:
raise BufferError('empty first buffer')
if self._length == 0:
raise BufferError('empty buffer')
if self._pos0 == self._len0:
self._switch_to_next_buf()
cdef _switch_to_next_buf(self):
# The first buffer is fully read, discard it
self._bufs_popleft()
self._bufs_len -= 1
# Shouldn't fail, since we've checked that `_length >= 1`
# in _ensure_first_buf()
self._buf0_prev = self._buf0
self._buf0 = <bytes>self._bufs[0]
self._pos0 = 0
self._len0 = len(self._buf0)
if PG_DEBUG:
if self._len0 < 1:
raise BufferError(
'debug: second buffer of ReadBuffer is empty')
cdef inline const char* _try_read_bytes(self, ssize_t nbytes):
# Try to read *nbytes* from the first buffer.
#
# Returns pointer to data if there is at least *nbytes*
# in the buffer, NULL otherwise.
#
# Important: caller must call _ensure_first_buf() prior
# to calling try_read_bytes, and must not overread
cdef:
const char *result
if PG_DEBUG:
if nbytes > self._length:
return NULL
if self._current_message_ready:
if self._current_message_len_unread < nbytes:
return NULL
if self._pos0 + nbytes <= self._len0:
result = cpython.PyBytes_AS_STRING(self._buf0)
result += self._pos0
self._pos0 += nbytes
self._length -= nbytes
if self._current_message_ready:
self._current_message_len_unread -= nbytes
return result
else:
return NULL
cdef inline _read_into(self, char *buf, ssize_t nbytes):
cdef:
ssize_t nread
char *buf0
while True:
buf0 = cpython.PyBytes_AS_STRING(self._buf0)
if self._pos0 + nbytes > self._len0:
nread = self._len0 - self._pos0
memcpy(buf, buf0 + self._pos0, <size_t>nread)
self._pos0 = self._len0
self._length -= nread
nbytes -= nread
buf += nread
self._ensure_first_buf()
else:
memcpy(buf, buf0 + self._pos0, <size_t>nbytes)
self._pos0 += nbytes
self._length -= nbytes
break
cdef inline _read_and_discard(self, ssize_t nbytes):
cdef:
ssize_t nread
self._ensure_first_buf()
while True:
if self._pos0 + nbytes > self._len0:
nread = self._len0 - self._pos0
self._pos0 = self._len0
self._length -= nread
nbytes -= nread
self._ensure_first_buf()
else:
self._pos0 += nbytes
self._length -= nbytes
break
cdef bytes read_bytes(self, ssize_t nbytes):
cdef:
bytes result
ssize_t nread
const char *cbuf
char *buf
self._ensure_first_buf()
cbuf = self._try_read_bytes(nbytes)
if cbuf != NULL:
return cpython.PyBytes_FromStringAndSize(cbuf, nbytes)
if nbytes > self._length:
raise BufferError(
'not enough data to read {} bytes'.format(nbytes))
if self._current_message_ready:
self._current_message_len_unread -= nbytes
if self._current_message_len_unread < 0:
raise BufferError('buffer overread')
result = cpython.PyBytes_FromStringAndSize(NULL, nbytes)
buf = cpython.PyBytes_AS_STRING(result)
self._read_into(buf, nbytes)
return result
cdef bytes read_len_prefixed_bytes(self):
cdef int32_t size = self.read_int32()
if size < 0:
raise BufferError(
'negative length for a len-prefixed bytes value')
if size == 0:
return b''
return self.read_bytes(size)
cdef str read_len_prefixed_utf8(self):
cdef:
int32_t size
const char *cbuf
size = self.read_int32()
if size < 0:
raise BufferError(
'negative length for a len-prefixed bytes value')
if size == 0:
return ''
self._ensure_first_buf()
cbuf = self._try_read_bytes(size)
if cbuf != NULL:
return cpython.PyUnicode_DecodeUTF8(cbuf, size, NULL)
else:
return self.read_bytes(size).decode('utf-8')
cdef read_uuid(self):
cdef:
bytes mem
const char *cbuf
self._ensure_first_buf()
cbuf = self._try_read_bytes(16)
if cbuf != NULL:
return pg_uuid_from_buf(cbuf)
else:
return pg_UUID(self.read_bytes(16))
cdef inline char read_byte(self) except? -1:
cdef const char *first_byte
if PG_DEBUG:
if not self._buf0:
raise BufferError(
'debug: first buffer of ReadBuffer is empty')
self._ensure_first_buf()
first_byte = self._try_read_bytes(1)
if first_byte is NULL:
raise BufferError('not enough data to read one byte')
return first_byte[0]
cdef inline int64_t read_int64(self) except? -1:
cdef:
bytes mem
const char *cbuf
self._ensure_first_buf()
cbuf = self._try_read_bytes(8)
if cbuf != NULL:
return hton.unpack_int64(cbuf)
else:
mem = self.read_bytes(8)
return hton.unpack_int64(cpython.PyBytes_AS_STRING(mem))
cdef inline int32_t read_int32(self) except? -1:
cdef:
bytes mem
const char *cbuf
self._ensure_first_buf()
cbuf = self._try_read_bytes(4)
if cbuf != NULL:
return hton.unpack_int32(cbuf)
else:
mem = self.read_bytes(4)
return hton.unpack_int32(cpython.PyBytes_AS_STRING(mem))
cdef inline int16_t read_int16(self) except? -1:
cdef:
bytes mem
const char *cbuf
self._ensure_first_buf()
cbuf = self._try_read_bytes(2)
if cbuf != NULL:
return hton.unpack_int16(cbuf)
else:
mem = self.read_bytes(2)
return hton.unpack_int16(cpython.PyBytes_AS_STRING(mem))
cdef inline read_null_str(self):
if not self._current_message_ready:
raise BufferError(
'read_null_str only works when the message guaranteed '
'to be in the buffer')
cdef:
ssize_t pos
ssize_t nread
bytes result
const char *buf
const char *buf_start
self._ensure_first_buf()
buf_start = cpython.PyBytes_AS_STRING(self._buf0)
buf = buf_start + self._pos0
while buf - buf_start < self._len0:
if buf[0] == 0:
pos = buf - buf_start
nread = pos - self._pos0
buf = self._try_read_bytes(nread + 1)
if buf != NULL:
return cpython.PyBytes_FromStringAndSize(buf, nread)
else:
break
else:
buf += 1
result = b''
while True:
pos = self._buf0.find(b'\x00', self._pos0)
if pos >= 0:
result += self._buf0[self._pos0 : pos]
nread = pos - self._pos0 + 1
self._pos0 = pos + 1
self._length -= nread
self._current_message_len_unread -= nread
if self._current_message_len_unread < 0:
raise BufferError(
'read_null_str: buffer overread')
return result
else:
result += self._buf0[self._pos0:]
nread = self._len0 - self._pos0
self._pos0 = self._len0
self._length -= nread
self._current_message_len_unread -= nread
if self._current_message_len_unread < 0:
raise BufferError(
'read_null_str: buffer overread')
self._ensure_first_buf()
cdef int32_t take_message(self) except -1:
cdef:
const char *cbuf
if self._current_message_ready:
return 1
if self._current_message_type == 0:
if self._length < 1:
return 0
self._ensure_first_buf()
cbuf = self._try_read_bytes(1)
if cbuf == NULL:
raise BufferError(
'failed to read one byte on a non-empty buffer')
self._current_message_type = cbuf[0]
if self._current_message_len == 0:
if self._length < 4:
return 0
self._ensure_first_buf()
cbuf = self._try_read_bytes(4)
if cbuf != NULL:
self._current_message_len = hton.unpack_int32(cbuf)
else:
self._current_message_len = self.read_int32()
self._current_message_len_unread = self._current_message_len - 4
if self._length < self._current_message_len_unread:
return 0
self._current_message_ready = 1
return 1
cdef inline int32_t take_message_type(self, char mtype) except -1:
cdef const char *buf0
if self._current_message_ready:
return self._current_message_type == mtype
elif self._length >= 1:
self._ensure_first_buf()
buf0 = cpython.PyBytes_AS_STRING(self._buf0)
return buf0[self._pos0] == mtype and self.take_message()
else:
return 0
cdef int32_t put_message(self) except -1:
if not self._current_message_ready:
raise BufferError(
'cannot put message: no message taken')
self._current_message_ready = False
return 0
cdef inline const char* try_consume_message(self, ssize_t* len):
cdef:
ssize_t buf_len
const char *buf
if not self._current_message_ready:
return NULL
self._ensure_first_buf()
buf_len = self._current_message_len_unread
buf = self._try_read_bytes(buf_len)
if buf != NULL:
len[0] = buf_len
self._finish_message()
return buf
cdef discard_message(self):
if not self._current_message_ready:
raise BufferError('no message to discard')
if self._current_message_len_unread > 0:
self._read_and_discard(self._current_message_len_unread)
self._current_message_len_unread = 0
self._finish_message()
cdef bytes consume_message(self):
if not self._current_message_ready:
raise BufferError('no message to consume')
if self._current_message_len_unread > 0:
mem = self.read_bytes(self._current_message_len_unread)
else:
mem = b''
self._finish_message()
return mem
cdef redirect_messages(self, WriteBuffer buf, char mtype,
int stop_at=0):
if not self._current_message_ready:
raise BufferError(
'consume_full_messages called on a buffer without a '
'complete first message')
if mtype != self._current_message_type:
raise BufferError(
'consume_full_messages called with a wrong mtype')
if self._current_message_len_unread != self._current_message_len - 4:
raise BufferError(
'consume_full_messages called on a partially read message')
cdef:
const char* cbuf
ssize_t cbuf_len
int32_t msg_len
ssize_t new_pos0
ssize_t pos_delta
int32_t done
while True:
buf.write_byte(mtype)
buf.write_int32(self._current_message_len)
cbuf = self.try_consume_message(&cbuf_len)
if cbuf != NULL:
buf.write_cstr(cbuf, cbuf_len)
else:
buf.write_bytes(self.consume_message())
if self._length > 0:
self._ensure_first_buf()
else:
return
if stop_at and buf._length >= stop_at:
return
# Fast path: exhaust buf0 as efficiently as possible.
if self._pos0 + 5 <= self._len0:
cbuf = cpython.PyBytes_AS_STRING(self._buf0)
new_pos0 = self._pos0
cbuf_len = self._len0
done = 0
# Scan the first buffer and find the position of the
# end of the last "mtype" message.
while new_pos0 + 5 <= cbuf_len:
if (cbuf + new_pos0)[0] != mtype:
done = 1
break
if (stop_at and
(buf._length + new_pos0 - self._pos0) > stop_at):
done = 1
break
msg_len = hton.unpack_int32(cbuf + new_pos0 + 1) + 1
if new_pos0 + msg_len > cbuf_len:
break
new_pos0 += msg_len
if new_pos0 != self._pos0:
assert self._pos0 < new_pos0 <= self._len0
pos_delta = new_pos0 - self._pos0
buf.write_cstr(
cbuf + self._pos0,
pos_delta)
self._pos0 = new_pos0
self._length -= pos_delta
assert self._length >= 0
if done:
# The next message is of a different type.
return
# Back to slow path.
if not self.take_message_type(mtype):
return
cdef bytearray consume_messages(self, char mtype):
"""Consume consecutive messages of the same type."""
cdef:
char *buf
ssize_t nbytes
ssize_t total_bytes = 0
bytearray result
if not self.take_message_type(mtype):
return None
# consume_messages is a volume-oriented method, so
# we assume that the remainder of the buffer will contain
# messages of the requested type.
result = cpythonx.PyByteArray_FromStringAndSize(NULL, self._length)
buf = cpythonx.PyByteArray_AsString(result)
while self.take_message_type(mtype):
self._ensure_first_buf()
nbytes = self._current_message_len_unread
self._read_into(buf, nbytes)
buf += nbytes
total_bytes += nbytes
self._finish_message()
# Clamp the result to an actual size read.
cpythonx.PyByteArray_Resize(result, total_bytes)
return result
cdef finish_message(self):
if self._current_message_type == 0 or not self._current_message_ready:
# The message has already been finished (e.g by consume_message()),
# or has been put back by put_message().
return
if self._current_message_len_unread:
if PG_DEBUG:
mtype = chr(self._current_message_type)
discarded = self.consume_message()
if PG_DEBUG:
print('!!! discarding message {!r} unread data: {!r}'.format(
mtype,
discarded))
self._finish_message()
cdef inline _finish_message(self):
self._current_message_type = 0
self._current_message_len = 0
self._current_message_ready = 0
self._current_message_len_unread = 0
@staticmethod
cdef ReadBuffer new_message_parser(object data):
cdef ReadBuffer buf
buf = ReadBuffer.__new__(ReadBuffer)
buf.feed_data(data)
buf._current_message_ready = 1
buf._current_message_len_unread = buf._len0
return buf
