1 files changed, 133 insertions, 0 deletions
diff --git a/soundconverter/queue.py b/soundconverter/queue.py
new file mode 100644
index 0000000..d0727e9
--- /dev/null
+++ b/soundconverter/queue.py
@@ -0,0 +1,133 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+#
+# SoundConverter - GNOME application for converting between audio formats.
+# Copyright 2004 Lars Wirzenius
+# Copyright 2005-2012 Gautier Portet
+#
+# 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; version 3 of the License.
+#
+# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+# USA
+
+import time
+from task import BackgroundTask
+from settings import settings
+from utils import log
+
+
+class TaskQueue(BackgroundTask):
+
+    """A queue of tasks.
+
+    A task queue is a queue of other tasks. If you need, for example, to
+    do simple tasks A, B, and C, you can create a TaskQueue and add the
+    simple tasks to it:
+
+        q = TaskQueue()
+        q.add_task(A)
+        q.add_task(B)
+        q.add_task(C)
+        q.start()
+
+    The task queue behaves as a single task. It will execute the
+    tasks in order and start the next one when the previous finishes."""
+
+    def __init__(self):
+        BackgroundTask.__init__(self)
+        self.waiting_tasks = []
+        self.running_tasks = []
+        self.finished_tasks = 0
+        self.start_time = None
+        self.count = 0
+        self.paused = False
+
+    def add_task(self, task):
+        """Add a task to the queue."""
+        self.waiting_tasks.append(task)
+        #if self.start_time and not self.running_tasks:
+        if self.start_time:
+            # add a task to a stalled taskqueue, shake it!
+            self.start_next_task()
+
+    def start_next_task(self):
+        if not self.waiting_tasks:
+            if not self.running_tasks:
+                self.done()
+            return
+
+        to_start = settings['jobs'] - len(self.running_tasks)
+        for i in range(to_start):
+            try:
+                task = self.waiting_tasks.pop(0)
+            except IndexError:
+                return
+            self.running_tasks.append(task)
+            task.add_listener('finished', self.task_finished)
+            task.start()
+            if self.paused:
+                task.toggle_pause(True)
+            self.count += 1
+        total = len(self.waiting_tasks) + self.finished_tasks
+        self.progress = float(self.finished_tasks) / total if total else 0
+
+    def started(self):
+        """ BackgroundTask setup callback """
+        log('Queue start: %d tasks, %d thread(s).' % (
+            len(self.waiting_tasks) + len(self.running_tasks),
+            settings['jobs']))
+        self.count = 0
+        self.paused = False
+        self.finished_tasks = 0
+        self.start_time = time.time()
+        self.start_next_task()
+
+    def finished(self):
+        """ BackgroundTask finish callback """
+        log('Queue done in %.3fs (%s tasks)' % (time.time() - self.start_time,
+                self.count))
+        self.queue_ended()
+        self.count = 0
+        self.start_time = None
+        self.running_tasks = []
+        self.waiting_tasks = []
+        self.running = False
+
+    def task_finished(self, task=None):
+        if not self.running_tasks:
+            return
+        if task in self.running_tasks:
+            self.running_tasks.remove(task)
+        self.finished_tasks += 1
+        self.start_next_task()
+
+    def abort(self):
+        for task in self.running_tasks:
+            task.abort()
+        BackgroundTask.abort(self)
+        self.running_tasks = []
+        self.waiting_tasks = []
+        self.running = False
+        self.start_time = None
+
+    def toggle_pause(self, paused):
+        self.paused = paused
+        for task in self.running_tasks:
+            task.toggle_pause(self.paused)
+
+    # The following is called when the Queue is finished
+    def queue_ended(self):
+        pass
+
+    # The following when progress changed
+    def progress_hook(self, progress):
+        pass