Add a couple of exceptions to avoid exiting from class methods

youtube-dl

@@ -25,6 +25,23 @@ std_headers = {
 
 simple_title_chars = string.ascii_letters.decode('ascii') + string.digits.decode('ascii')
 
+class DownloadError(Exception):
+	"""Download Error exception.
+	
+	This exception may be thrown by FileDownloader objects if they are not
+	configured to continue on errors. They will contain the appropriate
+	error message.
+	"""
+	pass
+
+class SameFileError(Exception):
+	"""Same File exception.
+
+	This exception will be thrown by FileDownloader objects if they detect
+	multiple files would have to be downloaded to the same file on disk.
+	"""
+	pass
+
 class FileDownloader(object):
 	"""File Downloader class.
 
@@ -165,22 +182,22 @@ class FileDownloader(object):
 		"""Determine action to take when a download problem appears.
 
 		Depending on if the downloader has been configured to ignore
-		download errors or not, this method may exit the program or
+		download errors or not, this method may throw an exception or
 		not when errors are found, after printing the message. If it
-		doesn't exit, it returns an error code suitable to be returned
+		doesn't raise, it returns an error code suitable to be returned
 		later as a program exit code to indicate error.
 		"""
 		if message is not None:
 			self.to_stderr(message)
 		if not self._params.get('ignoreerrors', False):
-			sys.exit(1)
+			raise DownloadError(message)
 		return 1
 
 	def download(self, url_list):
 		"""Download a given list of URLs."""
 		retcode = 0
 		if len(url_list) > 1 and self.fixed_template():
-			sys.exit('ERROR: fixed output name but more than one file to download')
+			raise SameFileError(self._params['outtmpl'])
 
 		for url in url_list:
 			suitable_found = False
@@ -195,7 +212,7 @@ class FileDownloader(object):
 					retcode = self.trouble()
 
 				if len(results) > 1 and self.fixed_template():
-					sys.exit('ERROR: fixed output name but more than one file to download')
+					raise SameFileError(self._params['outtmpl'])
 
 				for result in results:
 
@@ -401,7 +418,8 @@ class YoutubeIE(InfoExtractor):
 			self.to_stdout('[youtube] Confirming age')
 			age_results = urllib2.urlopen(request).read()
 		except (urllib2.URLError, httplib.HTTPException, socket.error), err:
-			sys.exit('ERROR: unable to confirm age: %s' % str(err))
+			self.to_stderr('ERROR: unable to confirm age: %s' % str(err))
+			return
 
 	def _real_extract(self, url):
 		# Extract video id from URL
@@ -429,7 +447,8 @@ class YoutubeIE(InfoExtractor):
 			self.to_stdout('[youtube] %s: Downloading video webpage' % video_id)
 			video_webpage = urllib2.urlopen(request).read()
 		except (urllib2.URLError, httplib.HTTPException, socket.error), err:
-			sys.exit('ERROR: unable to download video: %s' % str(err))
+			self.to_stderr('ERROR: unable to download video webpage: %s' % str(err))
+			return [None]
 		self.to_stdout('[youtube] %s: Extracting video information' % video_id)
 		
 		# "t" param
@@ -558,5 +577,9 @@ if __name__ == '__main__':
 		retcode = fd.download(args)
 		sys.exit(retcode)
 
+	except DownloadError:
+		sys.exit(1)
+	except SameFileError:
+		sys.exit('ERROR: fixed output name but more than one file to download')
 	except KeyboardInterrupt:
 		sys.exit('\nERROR: Interrupted by user')