1 files changed, 127 insertions, 0 deletions
diff --git a/ranger/core/loader.py b/ranger/core/loader.py
new file mode 100644
index 00000000..4f4424e4
--- /dev/null
+++ b/ranger/core/loader.py
@@ -0,0 +1,127 @@
+# 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
+from ranger.shared import FileManagerAware
+import math
+
+def status_generator():
+	"""Generate a rotating line which can be used as a throbber"""
+	while True:
+		yield '/'
+		yield '-'
+		yield '\\'
+		yield '|'
+
+class LoadableObject(object):
+	def __init__(self, gen, descr):
+		self.load_generator = gen
+		self.description = descr
+
+	def get_description(self):
+		return self.description
+
+
+class Loader(FileManagerAware):
+	seconds_of_work_time = 0.03
+
+	def __init__(self):
+		self.queue = deque()
+		self.item = None
+		self.load_generator = None
+		self.status_generator = status_generator()
+		self.rotate()
+		self.old_item = None
+
+	def rotate(self):
+		"""Rotate the throbber"""
+		# TODO: move all throbber logic to UI
+		self.status = next(self.status_generator)
+
+	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)
+		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()
+			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:
+			self.old_item = item
+
+		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)