compute-safer-cpp-statistics should report the number of files

https://bugs.webkit.org/show_bug.cgi?id=299572

Reviewed by Geoffrey Garen.

Print out the number of files in addition to the percentage of lines covered.

* Tools/Scripts/compute-safer-cpp-statistics:
(gather_statistics):
(print_percentage):
(main):

Canonical link: https://commits.webkit.org/300545@main

Author: rniwa

Tools/Scripts/compute-safer-cpp-statistics

@@ -113,22 +113,26 @@ def gather_statistics(line_counts, checkers, file_to_expectations_map, dir_path,
         expected_checkers = file_to_expectations_map.get(file_key)
         if expected_checkers:
             line_counts['unsafe'] += number_of_lines
+            line_counts['unsafeFiles'] += 1
         else:
             line_counts['safe'] += number_of_lines
+            line_counts['safeFiles'] += 1
         for checker in checkers:
             per_checker_counts = line_counts['checkers'][checker.name()]
             if expected_checkers and checker.name() in expected_checkers:
                 per_checker_counts['unsafe'] += number_of_lines
+                per_checker_counts['unsafeFiles'] += 1
             else:
                 per_checker_counts['safe'] += number_of_lines
+                per_checker_counts['safeFiles'] += 1
 
 
 def safe_ratio(line_counts):
     return line_counts['safe'] / (line_counts['safe'] + line_counts['unsafe'])
 
 
 def print_percentage(label, line_counts):
-    return print('{}: {:.2f}% safe'.format(label, safe_ratio(line_counts) * 100))
+    return print('{}: {:.2f}% safe ({} safe files / {} unsafe files)'.format(label, safe_ratio(line_counts) * 100, line_counts['safeFiles'], line_counts['unsafeFiles']))
 
 
 def main():
@@ -139,9 +143,9 @@ def main():
         return
 
     file_to_expectations_map = load_expectations(checkers, args.project)
-    line_counts = {'safe': 0, 'unsafe': 0, 'checkers': {}}
+    line_counts = {'safe': 0, 'unsafe': 0, 'safeFiles': 0, 'unsafeFiles': 0, 'checkers': {}}
     for checker in checkers:
-        line_counts['checkers'][checker.name()] = {'safe': 0, 'unsafe': 0}
+        line_counts['checkers'][checker.name()] = {'safe': 0, 'unsafe': 0, 'safeFiles': 0, 'unsafeFiles': 0}
 
     project = args.project
     project_path = Checker.enumerate()[0].project_path(project)