first version of single-process dispatcher

tracker: Issue #564

overviewer_core/dispatcher.py

@@ -0,0 +1,47 @@
+#    This file is part of the Minecraft Overviewer.
+#
+#    Minecraft Overviewer 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.
+#
+#    Minecraft Overviewer 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 the Overviewer.  If not, see <http://www.gnu.org/licenses/>.
+
+import util
+
+class Dispatcher(object):
+    def render_all(self, tilesetlist, status_callback):
+        # TODO use status callback
+        
+        # preprocessing
+        for tileset in tilesetlist:
+            tileset.do_preprocessing()
+        
+        # iterate through all possible phases
+        num_phases = [tileset.get_num_phases() for tileset in tilesetlist]
+        for phase in xrange(max(num_phases)):
+            # construct a list of iterators to use for this phase
+            work_iterators = []
+            for i, tileset in enumerate(tilesetlist):
+                if phase < num_phases[i]:
+                    def make_work_iterator(tset, p):
+                        return ((tset, workitem) for workitem in tset.iterate_work_items(p))
+                    work_iterators.append(make_work_iterator(tileset, phase))
+            
+            # go through these iterators round-robin style
+            for tileset, workitem in util.roundrobin(work_iterators):
+                self.dispatch(tileset, workitem)
+            
+            # after each phase, wait for the jobs to finish
+            self.finish_jobs()
+    
+    def dispatch(self, tileset, workitem):
+        tileset.do_work(workitem)
+    def finish_jobs(self):
+        pass