Add line numbers to parsing errors

src/main-export-known-hosts.py

@@ -4,12 +4,14 @@ import process_known_hosts
 import write_file
 
 def main():
-	entries = []
 	# TODO: Don't hardcode
 	# TODO: Handle errors
 	with open(sys.argv[1], 'r') as f:
-		for line in f:
-			entries.extend(process_known_hosts.process_line(line))
+		try:
+			entries = process_known_hosts.process_file(f)
+		except Exception as err:
+			print('Error: %s' % err, file=sys.stderr)
+			sys.exit(1)
 
 	with open('known_hosts.sshwot', 'wb') as f:
 		write_file.write(f, entries)

src/process_known_hosts.py

@@ -3,10 +3,27 @@ import hashlib
 
 import entry
 
-# TODO: Include line number in the error
-class KnownHostsSyntaxError(Exception): pass
+class KnownHostsSyntaxError(Exception):
+	def __init__(self, string):
+		self.string = string
+		self.line = None
 
-class HashedHostError(Exception): pass
+	def __str__(self):
+		if self.line == None:
+			return self.string
+		else:
+			return 'Line %i: %s' % (self.line, self.string)
+
+class HashedHostError(Exception):
+	def __init__(self, string):
+		self.string = string
+		self.line = None
+
+	def __str__(self):
+		if self.line == None:
+			return self.string
+		else:
+			return 'Line %i: %s' % (self.line, self.string)
 
 def process_line(line):
 	# TODO: Add a way to skip IPs
@@ -15,8 +32,6 @@ def process_line(line):
 	a list of Entries based on it."""
 	assert type(line) == str
 
-	# TODO: Skip over IPs somehow?
-
 	# Remove trailing newlines
 	if line[-1] == '\n': line = line[:-1]
 
@@ -78,3 +93,19 @@ def process_line(line):
 		entries.append(entry.create_entry(domain, port, fingerprint, ''))
 
 	return entries
+
+def process_file(f):
+	"""process_file(file(r)) → [Entry]
+	Given a file in the .ssh/known_hosts format, create a list of
+	entries"""
+
+	entries = []
+	# Line numbers are 1-indexed but enumerate 0-indexes
+	for linenum_minus_one, line in enumerate(f):
+		try:
+			entries.extend(process_line(line))
+		except (KnownHostsSyntaxError, HashedHostError) as err:
+			err.line = linenum_minus_one + 1
+			raise err
+
+	return entries

src/read_file.py

@@ -2,10 +2,27 @@ import base64
 
 import entry
 
-# TODO: Include file number in the error info
-class FileFormatError(Exception): pass
+class FileFormatError(Exception):
+	def __init__(self, string):
+		self.string = string
+		self.line = None
 
-class VersionMismatch(Exception): pass
+	def __str__(self):
+		if self.line == None:
+			return self.string
+		else:
+			return 'Line %i: %s' % (self.line, self.string)
+
+class VersionMismatch(Exception):
+	def __init__(self, string):
+		self.string = string
+		self.line = None
+
+	def __str__(self):
+		if self.line == None:
+			return self.string
+		else:
+			return 'Line %i: %s' % (self.line, self.string)
 
 def parse_header(header):
 	"""parse_header(bytes) → str
@@ -105,10 +122,21 @@ def read(f):
 	if len(lines) == 0:
 		raise FileFormatError('Missing header')
 
-	file_comment = parse_header(lines[0])
+	try:
+		file_comment = parse_header(lines[0])
+	except (FileFormatError, VersionMismatch) as err:
+		err.line = 1
+		raise err
 
 	entries = []
-	for line in lines[1:]:
-		entries.append(parse_entry(line))
+	# Since line numbers are 1-indexed while lists in python are
+	# 0-indexed and we handle the first one separately, first one in the
+	# list is line 2
+	for linenum_minus_2, line in enumerate(lines[1:]):
+		try:
+			entries.append(parse_entry(line))
+		except FileFormatError as err:
+			err.line = linenum_minus_2 + 2
+			raise err
 
 	return entries, file_comment