Fixed m3u and cue sheet generation

Added conditional to `program.write_m3u()` to
ignore skipped tracks.

Added skipped_tracks support to the `Program` and
`image.ImageVerifyTask` classes to avoid crashing
when a file for a skipped track doesn't exist.

Added conditional to `accurip.calculate_checksums`
to check if a path exists before trying to calculate
checksums, this prevents `accuraterip-checksum.c` from
emitting an error message (`sf_open failed!`) when a
path doesn't exist (as when a track is skipped).

Signed-off-by: blueblots <63152708+blueblots@users.noreply.github.com>

whipper/common/program.py

@@ -57,6 +57,7 @@ class Program:
     metadata = None
     outdir = None
     result = None
+    skipped_tracks = None
 
     def __init__(self, config, record=False):
         """
@@ -612,7 +613,12 @@ class Program:
         """
         cueImage = image.Image(self.cuePath)
         # assigns track lengths
-        verifytask = image.ImageVerifyTask(cueImage)
+        if self.skipped_tracks is not None:
+            verifytask = image.ImageVerifyTask(cueImage,
+                                               [os.path.basename(t.filename)
+                                                for t in self.skipped_tracks])
+        else:
+            verifytask = image.ImageVerifyTask(cueImage)
         runner.run(verifytask)
         if verifytask.exception:
             logger.error(verifytask.exceptionMessage)
@@ -627,6 +633,7 @@ class Program:
         ])
         if not (checksums and any(checksums['v1']) and any(checksums['v2'])):
             return False
+
         return accurip.verify_result(self.result, responses, checksums)
 
     def write_m3u(self, discname):
@@ -637,6 +644,8 @@ class Program:
                 if not track.filename:
                     # false positive htoa
                     continue
+                if track.skipped:
+                    continue
                 if track.number == 0:
                     length = (self.result.table.getTrackStart(1) /
                               common.FRAMES_PER_SECOND)