lint: Extract check_file_for_pattern().

tools/linter_lib/custom_check.py

@@ -11,6 +11,7 @@ from zulint.printer import print_err, colors
 
 from typing import cast, Any, Callable, Dict, List, Optional, Tuple, Iterable
 
+Rule = Dict[str, Any]
 RuleList = List[Dict[str, Any]]
 LineTup = Tuple[int, str, str, str]
 
@@ -95,18 +96,25 @@ def get_rules_applying_to_fn(fn: str, rules: RuleList) -> RuleList:
 
     return rules_to_apply
 
-def custom_check_file(fn: str,
+def check_file_for_pattern(fn: str,
+                           line_tups: List[LineTup],
                            identifier: str,
-                      rules: RuleList,
                            color: Optional[Iterable[str]],
-                      max_length: Optional[int]=None) -> bool:
-    failed = False
+                           rule: Rule) -> bool:
 
-    line_tups = get_line_info_from_file(fn=fn)
+    '''
+    DO NOT MODIFY THIS FUNCTION WITHOUT PROFILING.
 
-    rules_to_apply = get_rules_applying_to_fn(fn=fn, rules=rules)
+    This function gets called ~40k times, once per file per regex.
 
-    for rule in rules_to_apply:
+    Inside it's doing a regex check for every line in the file, so
+    it's important to do things like pre-compiling regexes.
+
+    DO NOT INLINE THIS FUNCTION.
+
+    We need to see it show up in profiles, and the function call
+    overhead will never be a bottleneck.
+    '''
     exclude_lines = {
         line for
         (exclude_fn, line) in rule.get('exclude_line', set())
@@ -114,7 +122,9 @@ def custom_check_file(fn: str,
     }
 
     pattern = re.compile(rule['pattern'])
-        strip_rule = rule.get('strip')
+    strip_rule = rule.get('strip')  # type: Optional[str]
+
+    ok = True
     for (i, line, line_newline_stripped, line_fully_stripped) in line_tups:
         if line_fully_stripped in exclude_lines:
             exclude_lines.remove(line_fully_stripped)
@@ -133,7 +143,7 @@ def custom_check_file(fn: str,
                 print_err(identifier, color, '{} at {} line {}:'.format(
                     rule['description'], fn, i+1))
                 print_err(identifier, color, line)
-                    failed = True
+                ok = False
         except Exception:
             print("Exception with %s at %s line %s" % (rule['pattern'], fn, i+1))
             traceback.print_exc()
@@ -141,6 +151,30 @@ def custom_check_file(fn: str,
     if exclude_lines:
         print('Please remove exclusions for file %s: %s' % (fn, exclude_lines))
 
+    return ok
+
+def custom_check_file(fn: str,
+                      identifier: str,
+                      rules: RuleList,
+                      color: Optional[Iterable[str]],
+                      max_length: Optional[int]=None) -> bool:
+    failed = False
+
+    line_tups = get_line_info_from_file(fn=fn)
+
+    rules_to_apply = get_rules_applying_to_fn(fn=fn, rules=rules)
+
+    for rule in rules_to_apply:
+        ok = check_file_for_pattern(
+            fn=fn,
+            line_tups=line_tups,
+            identifier=identifier,
+            color=color,
+            rule=rule,
+        )
+        if not ok:
+            failed = True
+
     # TODO: Move the below into more of a framework.
     firstline = None
     lastLine = None