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# Copyright 2014-2021 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser. If not, see <https://www.gnu.org/licenses/>.
"""qutebrowser has the concept of functions, exposed to the user as commands.
Creating a new command is straightforward::
from qutebrowser.api import cmdutils
@cmdutils.register(...)
def foo():
...
The commands arguments are automatically deduced by inspecting your function.
The types of the function arguments are inferred based on their default values,
e.g., an argument `foo=True` will be converted to a flag `-f`/`--foo` in
qutebrowser's commandline.
The type can be overridden using Python's function annotations::
@cmdutils.register(...)
def foo(bar: int, baz=True):
...
Possible values:
- A callable (``int``, ``float``, etc.): Gets called to validate/convert the
value.
- A python enum type: All members of the enum are possible values.
- A ``typing.Union`` of multiple types above: Any of these types are valid
values, e.g., ``Union[str, int]``.
"""
import inspect
from typing import Any, Callable, Iterable
from qutebrowser.utils import qtutils
from qutebrowser.commands import command, cmdexc
# pylint: disable=unused-import
from qutebrowser.utils.usertypes import KeyMode, CommandValue as Value
class CommandError(cmdexc.Error):
"""Raised when a command encounters an error while running.
If your command handler encounters an error and cannot continue, raise this
exception with an appropriate error message::
raise cmdexc.CommandError("Message")
The message will then be shown in the qutebrowser status bar.
.. note::
You should only raise this exception while a command handler is run.
Raising it at another point causes qutebrowser to crash due to an
unhandled exception.
"""
def check_overflow(arg: int, ctype: str) -> None:
"""Check if the given argument is in bounds for the given type.
Args:
arg: The argument to check.
ctype: The C++/Qt type to check as a string ('int'/'int64').
"""
try:
qtutils.check_overflow(arg, ctype)
except OverflowError:
raise CommandError("Numeric argument is too large for internal {} "
"representation.".format(ctype))
def check_exclusive(flags: Iterable[bool], names: Iterable[str]) -> None:
"""Check if only one flag is set with exclusive flags.
Raise a CommandError if not.
Args:
flags: The flag values to check.
names: A list of names (corresponding to the flags argument).
"""
if sum(1 for e in flags if e) > 1:
argstr = '/'.join('-' + e for e in names)
raise CommandError("Only one of {} can be given!".format(argstr))
_CmdHandlerType = Callable[..., Any]
class register: # noqa: N801,N806 pylint: disable=invalid-name
"""Decorator to register a new command handler."""
def __init__(self, *,
instance: str = None,
name: str = None,
deprecated_name: str = None,
**kwargs: Any) -> None:
"""Save decorator arguments.
Gets called on parse-time with the decorator arguments.
Args:
See class attributes.
"""
# The object from the object registry to be used as "self".
self._instance = instance
# The name of the command
self._name = name
# A possible deprecated alias (old name) of the command
self._deprecated_name = deprecated_name
# The arguments to pass to Command.
self._kwargs = kwargs
def __call__(self, func: _CmdHandlerType) -> _CmdHandlerType:
"""Register the command before running the function.
Gets called when a function should be decorated.
Doesn't actually decorate anything, but creates a Command object and
registers it in the global commands dict.
Args:
func: The function to be decorated.
Return:
The original function (unmodified).
"""
if self._name is None:
name = func.__name__.lower().replace('_', '-')
else:
assert isinstance(self._name, str), self._name
name = self._name
cmd = command.Command(
name=name,
instance=self._instance,
handler=func,
**self._kwargs,
)
cmd.register()
if self._deprecated_name is not None:
deprecated_cmd = command.Command(
name=self._deprecated_name,
instance=self._instance,
handler=func,
deprecated=f"use {name} instead",
**self._kwargs,
)
deprecated_cmd.register()
# This is checked by future @cmdutils.argument calls so they fail
# (as they'd be silently ignored otherwise)
func.qute_args = None # type: ignore[attr-defined]
return func
class argument: # noqa: N801,N806 pylint: disable=invalid-name
"""Decorator to customize an argument.
You can customize how an argument is handled using the
``@cmdutils.argument`` decorator *after* ``@cmdutils.register``. This can,
for example, be used to customize the flag an argument should get::
@cmdutils.register(...)
@cmdutils.argument('bar', flag='c')
def foo(bar):
...
For a ``str`` argument, you can restrict the allowed strings using
``choices``::
@cmdutils.register(...)
@cmdutils.argument('bar', choices=['val1', 'val2'])
def foo(bar: str):
...
For ``Union`` types, the given ``choices`` are only checked if other
types (like ``int``) don't match.
The following arguments are supported for ``@cmdutils.argument``:
- ``flag``: Customize the short flag (``-x``) the argument will get.
- ``value``: Tell qutebrowser to fill the argument with special values:
* ``value=cmdutils.Value.count``: The ``count`` given by the user to the
command.
* ``value=cmdutils.Value.win_id``: The window ID of the current window.
* ``value=cmdutils.Value.cur_tab``: The tab object which is currently
focused.
- ``completion``: A completion function to use when completing arguments
for the given command.
- ``choices``: The allowed string choices for the argument.
The name of an argument will always be the parameter name, with any
trailing underscores stripped and underscores replaced by dashes.
"""
def __init__(self, argname: str, **kwargs: Any) -> None:
self._argname = argname # The name of the argument to handle.
self._kwargs = kwargs # Valid ArgInfo members.
def __call__(self, func: _CmdHandlerType) -> _CmdHandlerType:
funcname = func.__name__
if self._argname not in inspect.signature(func).parameters:
raise ValueError("{} has no argument {}!".format(funcname,
self._argname))
if not hasattr(func, 'qute_args'):
func.qute_args = {} # type: ignore[attr-defined]
elif func.qute_args is None:
raise ValueError("@cmdutils.argument got called above (after) "
"@cmdutils.register for {}!".format(funcname))
arginfo = command.ArgInfo(**self._kwargs)
func.qute_args[self._argname] = arginfo # type: ignore[attr-defined]
return func
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