Read the .sshwot file to memory

src/read_file.py

@@ -0,0 +1,67 @@
+import entry
+
+class FileFormatError(Exception): pass
+
+class VersionMismatch(Exception): pass
+
+def check_header(f):
+	"""check_header(file(rb))
+	Throw an error if the header isn't good"""
+	# Magic is b'WOT'
+	magic = f.read(3)
+	if magic != b'WOT':
+		raise FileFormatError('Invalid magic')
+
+	# Version 0 is the current one
+	version = f.read(1)
+	if version == b'':
+		raise FileFormatError('Unexpected end of file')
+	if version != b'\0':
+		raise VersionMismatch('Version %i not supported' % version[0])
+
+def read_entry(f):
+	"""read_entry(file(rb)) → Entry / None
+	Returns None if the end of file has been reached"""
+	# u8[32]: salt
+	salt = f.read(32)
+	if len(salt) == 0:
+		# End of file has been reached, return None to mark that
+		return None
+	elif len(salt) != 32:
+		raise FileFormatError('Unexpected end of file')
+
+	# u8[32]: hashed_host
+	hashed_host = f.read(32)
+	if len(hashed_host) != 32:
+		raise FileFormatError('Unexpected end of file')
+
+	# u8[32]: fingerprint
+	fingerprint = f.read(32)
+	if len(fingerprint) != 32:
+		raise FileFormatError('Unexpected end of file')
+
+	# u16le: comment_length
+	length_bytes = f.read(2)
+	if len(length_bytes) != 2:
+		raise FileFormatError('Unexpected end of file')
+	comment_length = length_bytes[0] | length_bytes[1] << 8
+
+	# u8[comment_length]: comment
+	comment = f.read(comment_length)
+	if len(comment) != comment_length:
+		raise FileFormatError('Unexpected end of file')
+
+	return entry.Entry(salt, hashed_host, fingerprint, comment)
+
+def read(f):
+	"""read_file(file(rb)) → [Entry]"""
+	check_header(f)
+
+	entries = []
+	while True:
+		# Read until we reach the end of file
+		entry = read_entry(f)
+		if entry is None: break
+		entries.append(entry)
+
+	return entries