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# ##### BEGIN GPL LICENSE BLOCK #####
#
# This program 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 2
# of the License, or (at your option) any later version.
#
# This program 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 this program; if not, write to the Free Software Foundation,
# Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# ##### END GPL LICENSE BLOCK #####
# <pep8 compliant>
"""
Defines an operator mix-in to use for non-blocking command line access.
"""
class SubprocessHelper:
"""
Mix-in class for operators to run commands in a non-blocking way.
This uses a modal operator to manage an external process.
Subclass must define:
``command``:
List of arguments to pass to subprocess.Popen
report_interval: Time in seconds between updating reports.
``process_pre()``:
Callback that runs before the process executes.
``process_post(returncode)``:
Callback that runs when the process has ende.
returncode is -1 if the process was terminated.
"""
@staticmethod
def _non_blocking_readlines(f, chunk=64):
"""
Iterate over lines, yielding b'' when nothings left
or when new data is not yet available.
"""
import os
from .pipe_non_blocking import (
pipe_non_blocking_set,
pipe_non_blocking_is_error_blocking,
PortableBlockingIOError,
)
fd = f.fileno()
pipe_non_blocking_set(fd)
blocks = []
while True:
try:
data = os.read(fd, chunk)
if not data:
# case were reading finishes with no trailing newline
yield b''.join(blocks)
blocks.clear()
except PortableBlockingIOError as ex:
if not pipe_non_blocking_is_error_blocking(ex):
raise ex
yield b''
continue
while True:
n = data.find(b'\n')
if n == -1:
break
yield b''.join(blocks) + data[:n + 1]
data = data[n + 1:]
blocks.clear()
blocks.append(data)
def _report_output(self):
stdout_line_iter, stderr_line_iter = self._buffer_iter
for line_iter, report_type in (
(stdout_line_iter, {'INFO'}),
(stderr_line_iter, {'WARNING'})
):
while True:
line = next(line_iter).rstrip() # rstrip all, to include \r on windows
if not line:
break
self.report(report_type, line.decode(encoding='utf-8', errors='surrogateescape'))
def _wm_enter(self, context):
wm = context.window_manager
window = context.window
self._timer = wm.event_timer_add(self.report_interval, window)
window.cursor_set('WAIT')
def _wm_exit(self, context):
wm = context.window_manager
window = context.window
wm.event_timer_remove(self._timer)
window.cursor_set('DEFAULT')
def process_pre(self):
pass
def process_post(self, returncode):
pass
def modal(self, context, event):
wm = context.window_manager
p = self._process
if event.type == 'ESC':
self.cancel(context)
self.report({'INFO'}, "Operation aborted by user")
return {'CANCELLED'}
elif event.type == 'TIMER':
if p.poll() is not None:
self._report_output()
self._wm_exit(context)
self.process_post(p.returncode)
return {'FINISHED'}
self._report_output()
return {'PASS_THROUGH'}
def execute(self, context):
import subprocess
self.process_pre()
try:
p = subprocess.Popen(
self.command,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE,
)
except FileNotFoundError as ex:
# Command not found
self.report({'ERROR'}, str(ex))
return {'CANCELLED'}
self._process = p
self._buffer_iter = (
iter(self._non_blocking_readlines(p.stdout)),
iter(self._non_blocking_readlines(p.stderr)),
)
wm = context.window_manager
wm.modal_handler_add(self)
self._wm_enter(context)
return {'RUNNING_MODAL'}
def cancel(self, context):
self._wm_exit(context)
self._process.kill()
self.process_post(-1)
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