# -*- coding: utf-8 -*-
"""
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MIoT event loop.
"""
import selectors
import heapq
import time
import traceback
from typing import Callable, TypeVar
import logging
import threading
from .miot_error import MIoTEvError
_LOGGER = logging.getLogger(__name__)
TimeoutHandle = TypeVar('TimeoutHandle')
class MIoTFdHandler:
"""File descriptor handler."""
fd: int
read_handler: Callable[[any], None]
read_handler_ctx: any
write_handler: Callable[[any], None]
write_handler_ctx: any
def __init__(
self, fd: int,
read_handler: Callable[[any], None] = None,
read_handler_ctx: any = None,
write_handler: Callable[[any], None] = None,
write_handler_ctx: any = None
) -> None:
self.fd = fd
self.read_handler = read_handler
self.read_handler_ctx = read_handler_ctx
self.write_handler = write_handler
self.write_handler_ctx = write_handler_ctx
class MIoTTimeout:
"""Timeout handler."""
key: TimeoutHandle
target: int
handler: Callable[[any], None]
handler_ctx: any
def __init__(
self, key: str = None, target: int = None,
handler: Callable[[any], None] = None,
handler_ctx: any = None
) -> None:
self.key = key
self.target = target
self.handler = handler
self.handler_ctx = handler_ctx
def __lt__(self, other):
return self.target < other.target
class MIoTEventLoop:
"""MIoT event loop."""
_poll_fd: selectors.DefaultSelector
_fd_handlers: dict[str, MIoTFdHandler]
_timer_heap: list[MIoTTimeout]
_timer_handlers: dict[str, MIoTTimeout]
_timer_handle_seed: int
# Label if the current fd handler is freed inside a read handler to
# avoid invalid reading.
_fd_handler_freed_in_read_handler: bool
def __init__(self) -> None:
self._poll_fd = selectors.DefaultSelector()
self._timer_heap = []
self._timer_handlers = {}
self._timer_handle_seed = 1
self._fd_handlers = {}
self._fd_handler_freed_in_read_handler = False
def loop_forever(self) -> None:
"""Run an event loop in current thread."""
next_timeout: int
while True:
next_timeout = 0
# Handle timer
now_ms: int = self.__get_monotonic_ms
while len(self._timer_heap) > 0:
timer: MIoTTimeout = self._timer_heap[0]
if timer is None:
break
if timer.target <= now_ms:
heapq.heappop(self._timer_heap)
del self._timer_handlers[timer.key]
if timer.handler:
timer.handler(timer.handler_ctx)
else:
next_timeout = timer.target-now_ms
break
# Are there any files to listen to
if next_timeout == 0 and self._fd_handlers:
next_timeout = None # None == infinite
# Wait for timers & fds
if next_timeout == 0:
# Neither timer nor fds exist, exit loop
break
# Handle fd event
events = self._poll_fd.select(
timeout=next_timeout/1000.0 if next_timeout else next_timeout)
for key, mask in events:
fd_handler: MIoTFdHandler = key.data
if fd_handler is None:
continue
self._fd_handler_freed_in_read_handler = False
fd_key = str(id(fd_handler.fd))
if fd_key not in self._fd_handlers:
continue
if (
mask & selectors.EVENT_READ > 0
and fd_handler.read_handler
):
fd_handler.read_handler(fd_handler.read_handler_ctx)
if (
mask & selectors.EVENT_WRITE > 0
and self._fd_handler_freed_in_read_handler is False
and fd_handler.write_handler
):
fd_handler.write_handler(fd_handler.write_handler_ctx)
def loop_stop(self) -> None:
"""Stop the event loop."""
if self._poll_fd:
self._poll_fd.close()
self._poll_fd = None
self._fd_handlers = {}
self._timer_heap = []
self._timer_handlers = {}
def set_timeout(
self, timeout_ms: int, handler: Callable[[any], None],
handler_ctx: any = None
) -> TimeoutHandle:
"""Set a timer."""
if timeout_ms is None or handler is None:
raise MIoTEvError('invalid params')
new_timeout: MIoTTimeout = MIoTTimeout()
new_timeout.key = self.__get_next_timeout_handle
new_timeout.target = self.__get_monotonic_ms + timeout_ms
new_timeout.handler = handler
new_timeout.handler_ctx = handler_ctx
heapq.heappush(self._timer_heap, new_timeout)
self._timer_handlers[new_timeout.key] = new_timeout
return new_timeout.key
def clear_timeout(self, timer_key: TimeoutHandle) -> None:
"""Stop and remove the timer."""
if timer_key is None:
return
timer: MIoTTimeout = self._timer_handlers.pop(timer_key, None)
if timer:
self._timer_heap = list(self._timer_heap)
self._timer_heap.remove(timer)
heapq.heapify(self._timer_heap)
def set_read_handler(
self, fd: int, handler: Callable[[any], None], handler_ctx: any = None
) -> bool:
"""Set a read handler for a file descriptor.
Returns:
bool: True, success. False, failed.
"""
self.__set_handler(
fd, is_read=True, handler=handler, handler_ctx=handler_ctx)
def set_write_handler(
self, fd: int, handler: Callable[[any], None], handler_ctx: any = None
) -> bool:
"""Set a write handler for a file descriptor.
Returns:
bool: True, success. False, failed.
"""
self.__set_handler(
fd, is_read=False, handler=handler, handler_ctx=handler_ctx)
def __set_handler(
self, fd, is_read: bool, handler: Callable[[any], None],
handler_ctx: any = None
) -> bool:
"""Set a handler."""
if fd is None:
raise MIoTEvError('invalid params')
fd_key: str = str(id(fd))
fd_handler = self._fd_handlers.get(fd_key, None)
if fd_handler is None:
fd_handler = MIoTFdHandler(fd=fd)
fd_handler.fd = fd
self._fd_handlers[fd_key] = fd_handler
read_handler_existed = fd_handler.read_handler is not None
write_handler_existed = fd_handler.write_handler is not None
if is_read is True:
fd_handler.read_handler = handler
fd_handler.read_handler_ctx = handler_ctx
else:
fd_handler.write_handler = handler
fd_handler.write_handler_ctx = handler_ctx
if fd_handler.read_handler is None and fd_handler.write_handler is None:
# Remove from epoll and map
try:
self._poll_fd.unregister(fd)
except (KeyError, ValueError, OSError) as e:
del e
self._fd_handlers.pop(fd_key, None)
# May be inside a read handler, if not, this has no effect
self._fd_handler_freed_in_read_handler = True
elif read_handler_existed is False and write_handler_existed is False:
# Add to epoll
events = 0x0
if fd_handler.read_handler:
events |= selectors.EVENT_READ
if fd_handler.write_handler:
events |= selectors.EVENT_WRITE
try:
self._poll_fd.register(fd, events=events, data=fd_handler)
except (KeyError, ValueError, OSError) as e:
_LOGGER.error(
'%s, register fd, error, %s, %s, %s, %s, %s',
threading.current_thread().name,
'read' if is_read else 'write',
fd_key, handler, e, traceback.format_exc())
self._fd_handlers.pop(fd_key, None)
return False
elif (
read_handler_existed != (fd_handler.read_handler is not None)
or write_handler_existed != (fd_handler.write_handler is not None)
):
# Modify epoll
events = 0x0
if fd_handler.read_handler:
events |= selectors.EVENT_READ
if fd_handler.write_handler:
events |= selectors.EVENT_WRITE
try:
self._poll_fd.modify(fd, events=events, data=fd_handler)
except (KeyError, ValueError, OSError) as e:
_LOGGER.error(
'%s, modify fd, error, %s, %s, %s, %s, %s',
threading.current_thread().name,
'read' if is_read else 'write',
fd_key, handler, e, traceback.format_exc())
self._fd_handlers.pop(fd_key, None)
return False
return True
@property
def __get_next_timeout_handle(self) -> str:
# Get next timeout handle, that is not larger than the maximum
# value of UINT64 type.
self._timer_handle_seed += 1
# uint64 max
self._timer_handle_seed %= 0xFFFFFFFFFFFFFFFF
return str(self._timer_handle_seed)
@property
def __get_monotonic_ms(self) -> int:
"""Get monotonic ms timestamp."""
return int(time.monotonic()*1000)