Timelapses: Do not try to use image counter if still set to None and synchronize decrementing of image counter via mutex as well

Possible fixes for #693, the latter maybe also for #690

CHANGELOG.md

@@ -2,11 +2,23 @@
 
 ## 1.1.2 (Unreleased)
 
+### Improvements
+
+* Added deletion of `*.pyc` files to `python setup.py clean` command, should help tremendously when switching branches (backported
+  from [9e014eb](https://github.com/foosel/OctoPrint/commit/9e014eba1feffde11ed0601d9c911b8cac9f3fb0))
+
 ### Bug Fixes
 
 * [#634](https://github.com/foosel/OctoPrint/pull/634) - Fixed missing `branch` fields in version dicts generated
   by versioneer
 * [IRC] Don't hiccup on slic3r filament_diameter comments generated for multi extruder setups
+* Small fixes for timelapse creation:
+  - [#344](https://github.com/foosel/OctoPrint/issues/344) - Made timelapses capable of coping with missing captures in between by decrementing the image counter again if there
+    was an error fetching the latest image from the snapshot URL (backport of [1a7a468](https://github.com/foosel/OctoPrint/commit/1a7a468eb65fdf2a13b4c7a7723280e822c9c34b)
+    and [bf9d5ef](https://github.com/foosel/OctoPrint/commit/bf9d5efe43a1e57aacd8512125082ddca06b4efc))
+  - [#693](https://github.com/foosel/OctoPrint/issues/693) -  Try not to capture an image if image counter is still unset
+  - [unreported] Synchronize image counter decrementing as well as incrementing to prevent rare race conditions when generating the
+    image file names
 
 ## 1.1.1 (2014-10-27)
 

src/octoprint/timelapse.py

@@ -226,8 +226,12 @@ class Timelapse(object):
 			self._logger.warn("Cannot capture image, capture directory is unset")
 			return
 
+		if self._imageNumber is None:
+			self._logger.warn("Cannot capture image, image number is unset")
+			return
+
 		with self._captureMutex:
-			filename = os.path.join(self._captureDir, "tmp_%05d.jpg" % (self._imageNumber))
+			filename = os.path.join(self._captureDir, "tmp_%05d.jpg" % self._imageNumber)
 			self._imageNumber += 1
 		self._logger.debug("Capturing image to %s" % filename)
 		captureThread = threading.Thread(target=self._captureWorker, kwargs={"filename": filename})
@@ -242,6 +246,7 @@ class Timelapse(object):
 			self._logger.debug("Image %s captured from %s" % (filename, self._snapshotUrl))
 		except:
 			self._logger.exception("Could not capture image %s from %s, decreasing image counter again" % (filename, self._snapshotUrl))
+			with self._captureMutex:
 				self._imageNumber -= 1
 		eventManager().fire(Events.CAPTURE_DONE, {"file": filename})