Detect and handle CD-R discs (#154)

* Use cdrdao to detect CD-Rs and continue ripping only if the argument --cdr is passed.

* Get and display disc format from MusicBrainz.

* Add info about CD-R detection to logger

* Remove Musicbrainz medium format info

* add cdrdao command to logger

* Fix for PEP8

* Fix line break

whipper/command/cd.py

@@ -143,6 +143,13 @@ class _CD(BaseCommand):
                                 "--unknown not passed")
                 return -1
 
+        self.program.result.isCdr = cdrdao.DetectCdr(self.device)
+        if (self.program.result.isCdr and
+                not getattr(self.options, 'cdr', False)):
+            logger.critical("inserted disc seems to be a CD-R, "
+                            "--cdr not passed")
+            return -1
+
         # FIXME ?????
         # Hackish fix for broken commit
         offset = 0
@@ -300,6 +307,11 @@ Log files will log the path to tracks relative to this directory.
                                  action="store_true", dest="unknown",
                                  help="whether to continue ripping if "
                                  "the CD is unknown", default=False)
+        self.parser.add_argument('--cdr',
+                                 action="store_true", dest="cdr",
+                                 help="whether to continue ripping if "
+                                 "the disc is a CD-R",
+                                 default=False)
 
     def handle_arguments(self):
         self.options.output_directory = os.path.expanduser(

whipper/program/cdrdao.py

@@ -47,6 +47,19 @@ def read_toc(device, fast_toc=False):
     return toc
 
 
+def DetectCdr(device):
+    """
+    Return whether cdrdao detects a CD-R for 'device'.
+    """
+    cmd = [CDRDAO, 'disk-info', '-v1', '--device', device]
+    logger.debug("executing %r", cmd)
+    p = Popen(cmd, stdout=PIPE, stderr=PIPE)
+    if 'CD-R medium          : n/a' in p.stdout.read():
+        return False
+    else:
+        return True
+
+
 def version():
     """
     Return cdrdao version as a string.

whipper/result/logger.py

@@ -54,6 +54,11 @@ class WhipperLogger(result.Logger):
         # Next one fully works only using the patched cdparanoia package
         # lines.append("Fill up missing offset samples with silence: Yes")
         lines.append("  Gap detection: cdrdao %s" % ripResult.cdrdaoVersion)
+        if ripResult.isCdr:
+            isCdr = "Yes"
+        else:
+            isCdr = "No"
+        lines.append("  CD-R detected: %s" % isCdr)
         lines.append("")
 
         # CD metadata

whipper/result/result.py

@@ -93,6 +93,7 @@ class RipResult:
 
     offset = 0
     overread = None
+    isCdr = None
     logger = None
     table = None
     artist = None