summary refs log tree commit diff stats
path: root/ranger/core/loader.py
blob: c03ecc29c0750e3d907f4e544142fe3c35dbe7ca (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
# Copyright (C) 2009, 2010  Roman Zimbelmann <romanz@lavabit.com>
#
# 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 3 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, see <http://www.gnu.org/licenses/>.

from collections import deque
from time import time, sleep
from subprocess import Popen, PIPE
from time import time
from ranger.core.shared import FileManagerAware
from ranger.ext.signal_dispatcher import SignalDispatcher
import math
import os
import select


class Loadable(object):
	paused = False
	def __init__(self, gen, descr):
		self.load_generator = gen
		self.description = descr

	def get_description(self):
		return self.description

	def pause(self):
		self.paused = True

	def unpause(self):
		try:
			del self.paused
		except:
			pass

	def destroy(self):
		pass


class CommandLoader(Loadable, SignalDispatcher, FileManagerAware):
	"""
	Run an external command with the loader.

	Output from stderr will be reported.  Ensure that the process doesn't
	ever ask for input, otherwise the loader will be blocked until this
	object is removed from the queue (type ^C in ranger)
	"""
	finished = False
	def __init__(self, args, descr):
		SignalDispatcher.__init__(self)
		Loadable.__init__(self, self.generate(), descr)
		self.args = args

	def generate(self):
		self.process = process = Popen(self.args,
				stdout=PIPE, stderr=PIPE)
		self.signal_emit('before', process=process)
		while process.poll() is None:
			try:
				rd, _, __ = select.select(
						[process.stderr], [], [], 0.05)
				if rd:
					error = process.stderr.readline().decode('utf-8')
					if error:
						self.fm.notify(error, bad=True)
			except select.error:
				pass
#			sleep(0.02)
			yield
		self.finished = True
		self.signal_emit('after', process=process)

	def pause(self):
		if not self.finished and not self.paused:
			self.process.send_signal(20)
		Loadable.pause(self)

	def unpause(self):
		if not self.finished and self.paused:
			self.process.send_signal(18)
		Loadable.unpause(self)

	def destroy(self):
		if self.process:
			self.process.kill()


class Loader(FileManagerAware):
	seconds_of_work_time = 0.03
	throbber_chars = r'/-\|'

	def __init__(self):
		self.queue = deque()
		self.item = None
		self.load_generator = None
		self.throbber_status = 0
		self.rotate()
		self.old_item = None

	def rotate(self):
		"""Rotate the throbber"""
		# TODO: move all throbber logic to UI
		self.throbber_status = \
			(self.throbber_status + 1) % len(self.throbber_chars)
		self.status = self.throbber_chars[self.throbber_status]

	def add(self, obj):
		"""
		Add an object to the queue.
		It should have a load_generator method.
		"""
		while obj in self.queue:
			self.queue.remove(obj)
		self.queue.appendleft(obj)

	def move(self, _from, to):
		try:
			item = self.queue[_from]
		except IndexError:
			return

		del self.queue[_from]

		if to == 0:
			self.queue.appendleft(item)
			if _from != 0:
				self.queue[1].pause()
		elif to == -1:
			self.queue.append(item)
		else:
			raise NotImplementedError

	def remove(self, item=None, index=None):
		if item is not None and index is None:
			for i, test in enumerate(self.queue):
				if test == item:
					index = i 
					break
			else:
				return

		if index is not None:
			if item is None:
				item = self.queue[index]
			if hasattr(item, 'unload'):
				item.unload()
			item.destroy()
			del self.queue[index]

	def work(self):
		"""
		Load items from the queue if there are any.
		Stop after approximately self.seconds_of_work_time.
		"""
		while True:
			# get the first item with a proper load_generator
			try:
				item = self.queue[0]
				if item.load_generator is None:
					self.queue.popleft()
				else:
					break
			except IndexError:
				return

		self.rotate()
		if item != self.old_item:
			if self.old_item:
				self.old_item.pause()
			self.old_item = item
		item.unpause()

		end_time = time() + self.seconds_of_work_time

		try:
			while time() < end_time:
				next(item.load_generator)
		except StopIteration:
			item.load_generator = None
			self.queue.remove(item)
		except Exception as err:
			self.fm.notify(err)

	def has_work(self):
		"""Is there anything to load?"""
		return bool(self.queue)

	def destroy(self):
		while self.queue:
			self.queue.pop().destroy()