cpython/Lib/_pyrepl/base_eventqueue.py at 3.15 · python/cpython · GitHub

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# Armin Rigo

# 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

cpython/Lib/_pyrepl/base_eventqueue.py at 3.15 · python/cpython · GitHub

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