Linux: ensure resources are freed in grab()

BoboTiG · BoboTiG · commit c95dd979c79c · 2018-12-26T22:22:23.000+01:00
diff --git a/CHANGELOG b/CHANGELOG
@@ -4,6 +4,7 @@ History:
 
 4.0.0   201x/xx/xx
       - MSS: renamed MSSBase to MSSMixin in base.py
+      - Linux: ensure resources are freed in grab()
       - MSS: fix Flake8 C408: Unnecessary dict call - rewrite as a literal, in exceptions.py
       - MSS: fix Flake8 I100: Import statements are in the wrong order
       - MSS: fix Flake8 I201: Missing newline before sections or imports
diff --git a/mss/linux.py b/mss/linux.py
@@ -406,22 +406,25 @@ def grab(self, monitor):
             ZPIXMAP,
         )
 
-        bits_per_pixel = ximage.contents.bits_per_pixel
-        if bits_per_pixel != 32:
-            raise ScreenShotError(
-                "[XImage] bits per pixel value not (yet?) implemented: {}.".format(
-                    bits_per_pixel
+        try:
+            bits_per_pixel = ximage.contents.bits_per_pixel
+            if bits_per_pixel != 32:
+                raise ScreenShotError(
+                    "[XImage] bits per pixel value not (yet?) implemented: {}.".format(
+                        bits_per_pixel
+                    )
                 )
-            )
 
-        data = ctypes.cast(
-            ximage.contents.data,
-            ctypes.POINTER(ctypes.c_ubyte * monitor["height"] * monitor["width"] * 4),
-        )
-        data = bytearray(data.contents)
-
-        # Free
-        self.xlib.XDestroyImage(ximage)
+            data = ctypes.cast(
+                ximage.contents.data,
+                ctypes.POINTER(
+                    ctypes.c_ubyte * monitor["height"] * monitor["width"] * 4
+                ),
+            )
+            data = bytearray(data.contents)
+        finally:
+            # Free
+            self.xlib.XDestroyImage(ximage)
 
         return self.cls_image(data, monitor)
 
