adds checksum.py script for SHA1 hash checksum list generation from font binaries and XML dumps of OpenType table data

Author: chrissimpkins

tools/scripts/checksum/checksum.py

@@ -0,0 +1,98 @@
+#!/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
+#
+# Copyright 2018 Christopher Simpkins
+# MIT License
+#
+# Usage: checksum.py (options) [file path 1]...[file path n]
+#
+# Dependencies: Python fontTools library
+#----------------------------------------------------------------
+
+import argparse
+import hashlib
+import os
+import sys
+
+from os.path import basename
+
+from fontTools.ttLib import TTFont
+
+
+def main(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):
+            sys.stderr.write("[checksum.py] ERROR: " + path + " is not a valid file path" + os.linesep)
+            sys.exit(1)
+
+        if use_ttx:
+            # append a .ttx extension to existing extension to maintain data about the binary that
+            # was used to generate the .ttx XML dump.  This creates unique checksum path values for
+            # paths that would otherwise not be unique with a file extension replacement with .ttx
+            # An example is woff and woff2 web font files that share the same base file name:
+            #
+            #  coolfont-regular.woff  ==> coolfont-regular.ttx
+            #  coolfont-regular.woff2 ==> coolfont-regular.ttx  (KAPOW! checksum data lost as this would overwrite dict value)
+            temp_ttx_path = path + ".ttx"
+
+            tt = TTFont(path)
+            tt.saveXML(temp_ttx_path, newlinestr="\n", skipTables=exclude_tables, tables=include_tables)
+            checksum_path = temp_ttx_path
+        else:
+            if include_tables is not None:
+                sys.stderr.write("[checksum.py] -i and --include are not supported for font binary filepaths. \
+                    Use these flags for checksums with the --ttx flag.")
+                sys.exit(1)
+            if exclude_tables is not None:
+                sys.stderr.write("[checksum.py] -e and --exclude are not supported for font binary filepaths. \
+                    Use these flags for checksums with the --ttx flag.")
+                sys.exit(1)
+            checksum_path = 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()
+
+        # remove temp ttx files when present
+        if use_ttx and do_not_cleanup is False:
+            os.remove(temp_ttx_path)
+
+    # generate the checksum list string for writes
+    checksum_out_data = ""
+    for key in checksum_dict.keys():
+        checksum_out_data += checksum_dict[key] + "  " + key + "\n"
+
+    # write to stdout stream or file based upon user request (default = file write)
+    if stdout_write:
+        sys.stdout.write(checksum_out_data)
+    else:
+        checksum_report_filepath = "checksum.txt"
+        with open(checksum_report_filepath, "w") as file:
+            file.write(checksum_out_data)
+
+
+def read_binary(filepath):
+    with open(filepath, mode='rb') as file:
+        return file.read()
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(prog="checksum.py")
+    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("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)