# Copyright 2000-2008 Michael Hudson-Doyle <micahel@gmail.com>
# Armin Rigo
#
# All Rights Reserved
#
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose is hereby granted without fee,
# provided that the above copyright notice appear in all copies and
# that both that copyright notice and this permission notice appear in
# supporting documentation.
#
# THE AUTHOR MICHAEL HUDSON DISCLAIMS ALL WARRANTIES WITH REGARD TO
# THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS, IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL,
# INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
# RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
# CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
"""
OS-independent base for an event and VT sequence scanner
See unix_eventqueue and windows_eventqueue for subclasses.
"""
from collections import deque
from . import keymap
from .console import Event
from .trace import trace
class BaseEventQueue:
def __init__(self, encoding: str, keymap_dict: dict[bytes, str]) -> None:
self.compiled_keymap = keymap.compile_keymap(keymap_dict)
self.keymap = self.compiled_keymap
trace("keymap {k!r}", k=self.keymap)
self.encoding = encoding
self.events: deque[Event] = deque()
self.buf = bytearray()
def get(self) -> Event | None:
"""
Retrieves the next event from the queue.
"""
if self.events:
return self.events.popleft()
else:
return None
def empty(self) -> bool:
"""
Checks if the queue is empty.
"""
return not self.events
def flush_buf(self) -> bytearray:
"""
Flushes the buffer and returns its contents.
"""
old = self.buf
self.buf = bytearray()
return old
def insert(self, event: Event) -> None:
"""
Inserts an event into the queue.
"""
trace('added event {event}', event=event)
self.events.append(event)
def push(self, char: int | bytes) -> None:
"""
Processes a character by updating the buffer and handling special key mappings.
"""
assert isinstance(char, (int, bytes))
ord_char = char if isinstance(char, int) else ord(char)
char = ord_char.to_bytes()
self.buf.append(ord_char)
if char in self.keymap:
if self.keymap is self.compiled_keymap:
# sanity check, buffer is empty when a special key comes
assert len(self.buf) == 1
k = self.keymap[char]
trace('found map {k!r}', k=k)
if isinstance(k, dict):
self.keymap = k
else:
self.insert(Event('key', k, bytes(self.flush_buf())))
self.keymap = self.compiled_keymap
elif self.buf and self.buf[0] == 27: # escape
# escape sequence not recognized by our keymap: propagate it
# outside so that i can be recognized as an M-... key (see also
# the docstring in keymap.py
trace('unrecognized escape sequence, propagating...')
self.keymap = self.compiled_keymap
self.insert(Event('key', '\033', b'\033'))
for _c in self.flush_buf()[1:]:
self.push(_c)
else:
try:
decoded = bytes(self.buf).decode(self.encoding)
except UnicodeError:
return
else:
self.insert(Event('key', decoded, bytes(self.flush_buf())))
self.keymap = self.compiled_keymap
