[checksum.py] adds support for checksum checks against file paths in …

…a valid checksum files

tools/scripts/checksum/checksum.py

@@ -1,18 +1,30 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-#----------------------------------------------------------------
+#------------------------------------------------------------------------------------------------------
 # checksum.py
 # A SHA1 hash checksum list generator for fonts and fontTools
-# XML dumps of font OpenType table data
+# XML dumps of font OpenType table data + checksum testing
+# script
 #
 # Copyright 2018 Christopher Simpkins
 # MIT License
 #
+# Dependencies: Python fontTools library
+#
 # Usage: checksum.py (options) [file path 1]...[file path n]
 #
-# Dependencies: Python fontTools library
-#----------------------------------------------------------------
+# Options:
+# -h, --help Help
+# -t, --ttx Calculate SHA1 hash values from ttx dump of XML (default = font binary)
+# -s, --stdout Stream to standard output stream (default = write to disk as 'checksum.txt')
+# -c, --check Test SHA1 checksum values against a valid checksum file
+#
+# Options, --ttx only:
+# -e, --exclude Excluded OpenType table (may be used more than once, mutually exclusive with -i)
+# -i, --include Included OpenType table (may be used more than once, mutually exclusive with -e)
+# -n, --noclean Do not discard .ttx files that are used to calculate SHA1 hashes
+#-------------------------------------------------------------------------------------------------------
 
 import argparse
 import hashlib
@@ -24,7 +36,7 @@
 from fontTools.ttLib import TTFont
 
 
-def main(filepaths, stdout_write=False, use_ttx=False, include_tables=None, exclude_tables=None, do_not_cleanup=False):
+def write_checksum(filepaths, stdout_write=False, use_ttx=False, include_tables=None, exclude_tables=None, do_not_cleanup=False):
  checksum_dict = {}
  for path in filepaths:
  if not os.path.exists(path):
@@ -42,6 +54,8 @@ def main(filepaths, stdout_write=False, use_ttx=False, include_tables=None, excl
  temp_ttx_path = path + ".ttx"
 
  tt = TTFont(path)
+ # important to keep the newlinestr value defined here as hash values will change across platforms
+ # if platform specific newline values are assumed
  tt.saveXML(temp_ttx_path, newlinestr="\n", skipTables=exclude_tables, tables=include_tables)
  checksum_path = temp_ttx_path
  else:
@@ -55,7 +69,7 @@ def main(filepaths, stdout_write=False, use_ttx=False, include_tables=None, excl
  sys.exit(1)
  checksum_path = path
 
- file_contents = read_binary(checksum_path)
+ file_contents = _read_binary(checksum_path)
 
  # store SHA1 hash data and associated file path basename in the checksum_dict dictionary
  checksum_dict[basename(checksum_path)] = hashlib.sha1(file_contents).hexdigest()
@@ -78,7 +92,48 @@ def main(filepaths, stdout_write=False, use_ttx=False, include_tables=None, excl
  file.write(checksum_out_data)
 
 
-def read_binary(filepath):
+def check_checksum(filepaths):
+ check_failed = False
+ for path in filepaths:
+ if not os.path.exists(path):
+ sys.stderr.write("[checksum.py] ERROR: " + filepath + " is not a valid filepath" + os.linesep)
+ sys.exit(1)
+
+ with open(path, mode='r') as file:
+ for line in file.readlines():
+ cleaned_line = line.rstrip()
+ line_list = cleaned_line.split(" ")
+ # eliminate empty strings parsed from > 1 space characters
+ line_list = list(filter(None, line_list))
+ if len(line_list) == 2:
+ expected_sha1 = line_list[0]
+ test_path = line_list[1]
+ else:
+ sys.stderr.write("[checksum.py] ERROR: failed to parse checksum file values" + os.linesep)
+ sys.exit(1)
+
+ if not os.path.exists(test_path):
+ print(test_path + ": Filepath is not valid, ignored")
+ else:
+ file_contents = _read_binary(test_path)
+ observed_sha1 = hashlib.sha1(file_contents).hexdigest()
+ if observed_sha1 == expected_sha1:
+ print(test_path + ": OK")
+ else:
+ print("-" * 80)
+ print(test_path + ": === FAIL ===")
+ print("Expected vs. Observed:")
+ print(expected_sha1)
+ print(observed_sha1)
+ print("-" * 80)
+ check_failed = True
+
+ # exit with status code 1 if any fails detected across all tests in the check
+ if check_failed is True:
+ sys.exit(1)
+
+
+def _read_binary(filepath):
  with open(filepath, mode='rb') as file:
  return file.read()
 
@@ -88,11 +143,15 @@ def read_binary(filepath):
  parser.add_argument("-t", "--ttx", help="Calculate from ttx file", action="store_true")
  parser.add_argument("-s", "--stdout", help="Write output to stdout stream", action="store_true")
  parser.add_argument("-n", "--noclean", help="Do not discard *.ttx files used to calculate SHA1 hashes", action="store_true")
+ parser.add_argument("-c", "--check", help="Verify checksum values vs. files", action="store_true")
  parser.add_argument("filepaths", nargs="+", help="One or more file paths to font binary files")
 
  parser.add_argument("-i", "--include", action="append", help="Included OpenType tables for ttx data dump")
  parser.add_argument("-e", "--exclude", action="append", help="Excluded OpenType tables for ttx data dump")
 
  args = parser.parse_args(sys.argv[1:])
 
- main(args.filepaths, stdout_write=args.stdout, use_ttx=args.ttx, do_not_cleanup=args.noclean, include_tables=args.include, exclude_tables=args.exclude)
+ if args.check is True:
+ check_checksum(args.filepaths)
+ else:
+ write_checksum(args.filepaths, stdout_write=args.stdout, use_ttx=args.ttx, do_not_cleanup=args.noclean, include_tables=args.include, exclude_tables=args.exclude)