[roottest] Refactor custom_diff.py

roottest/scripts/custom_diff.py

@@ -1,61 +1,85 @@
-""" Clever (with filters) compare command using difflib.py providing diffs in four formats:
-
-  * ndiff:    lists every line and highlights interline changes.
-  * context:  highlights clusters of changes in a before/after format.
-  * unified:  highlights clusters of changes in an inline format.
-  * html:     generates side by side comparison with change highlights.
-
-  """
-import sys, os, time, difflib, optparse, re
+"""Clever (with filters) compare command using difflib.py providing diffs in four formats:
+
+* ndiff:    lists every line and highlights interline changes.
+* context:  highlights clusters of changes in a before/after format.
+* unified:  highlights clusters of changes in an inline format.
+* html:     generates side by side comparison with change highlights.
+
+"""
+import difflib
+import optparse
+import os
+import re
+import sys
+import time
+
+
 #---------------------------------------------------------------------------------------------------------------------------
 #---Filter and substitutions------------------------------------------------------------------------------------------------
+class LineFilter:
+    """A line filter to suppress lines in the diff.
+    self.skip_regexes contains patterns to skip entirely.
+    self.substitutions contains patterns to replace with the given strings.
+    These patterns only need to be compiled once for all the incoming lines.
+    """
+
+    def __init__(self):
+        # Skip these lines
+        self.skip_regexes = [
+            re.compile(pattern)
+            for pattern in [
+                r"^Processing ",  # Interpreted macros
+                r"^Info in <\w+::ACLiC>: creating shared library",  # Compiled macros
+                r"^In file included from input_line",  # Wrapper input line
+                r"^[:space:]*$",  # Lines which are empty apart from spaces
+            ]
+        ]
+
+        # Replace these patterns in all lines
+        self.substitutions = [
+            (re.compile(r"[ ]@0x[a-fA-F0-9]+"), ""),  # Remove pointers from output
+            (re.compile(r"std::__[0-9]+::"), "std::"),  # Canonicalise standard namespaces
+            (
+                re.compile(r"^(\S*/|)([^:/]+)[-:0-9]*(?=: error:)"),
+                r"\2",
+            ),  # Trim file paths and line numbers from lines with ": error:"
+            (re.compile(r"(input_line_|ROOT_prompt_)[0-9]+"), r"\1--"),  # Canonicalise input_line_123, ROOT_prompt_345
+        ]
+
+    def filter(self, lines, ignoreWhiteSpace=False):
+        outlines = []
+        for line in lines:
+            if sys.platform == "win32":
+                if "Creating library " in line:
+                    continue
+                if "_ACLiC_dict" in line:
+                    continue
+                if "Warning in <TInterpreter::ReadRootmapFile>:" in line:
+                    continue
+                if "Warning in <TClassTable::Add>:" in line:
+                    continue
+                if "Error: Removing " in line:
+                    continue
+                if " -nologo -TP -c -nologo -I" in line:
+                    continue
+                if "rootcling -v1 -f " in line:
+                    continue
+                if "No precompiled header available" in line:
+                    continue
+
+            # ---Skip all lines matching predefined expressions---------------------------
+            if any(pattern.match(line) is not None for pattern in self.skip_regexes):
+                continue
 
-def filter(lines, ignoreWhiteSpace = False):
-  outlines = []
-  for line in lines:
-    if sys.platform == 'win32':
-      if 'Creating library ' in line:
-        continue
-      if '_ACLiC_dict' in line:
-        continue
-      if 'Warning in <TInterpreter::ReadRootmapFile>:' in line:
-        continue
-      if 'Warning in <TClassTable::Add>:' in line:
-        continue
-      if 'Error: Removing ' in line:
-        continue
-      if ' -nologo -TP -c -nologo -I' in line:
-        continue
-      if 'rootcling -v1 -f ' in line:
-        continue
-      if 'No precompiled header available' in line:
-        continue
-      #if line in ['\n', '\r\n']:
-      #  continue
-    #---Processing line from interpreter (root.exe)------------------------------
-    if re.match(r'^Processing ', line):
-      continue
-    #---ACLiC info---------------------------------------------------------------
-    if re.match(r'^Info in <\w+::ACLiC>: creating shared library', line):
-      continue
-    #---Compilation error--------------------------------------------------------
-    elif re.search(r': error:', line):
-      nline = re.sub(r'\S+/', '', line)
-      nline = re.sub(r'(:|_)[0-9]+(?=:)', ':--', nline)
-    #---Wrapper input line-------------------------------------------------------
-    elif re.match(r'^In file included from input_line', line):
-      continue
-    else:
-      nline = line
-    #---Remove Addresses in cling/cint-------------------------------------------
-    nline = re.sub(r'[ ]@0x[a-fA-F0-9]+', '', nline)
-    #---Remove versioning in std-------------------------------------------------
-    nline = re.sub(r'std::__[0-9]::', 'std::', nline)
-    #---Remove white spaces------------------------------------------------------
-    if (ignoreWhiteSpace):
-      nline = re.sub(r'[ ]', '', nline)
-    outlines.append(nline)
-  return outlines
+            # ---Apply predefined replacements--------------------------------------------
+            for pattern, replacement in self.substitutions:
+                line = pattern.sub(replacement, line)
+
+            # ---Remove white spaces------------------------------------------------------
+            if ignoreWhiteSpace:
+                line = re.sub(r"[ ]", "", line)
+            outlines.append(line)
+        return outlines
 
 #-----------------------------------------------------------------------------------------------------------------------------
 def main():
@@ -67,16 +91,16 @@ def main():
   parser.add_option("-n", action="store_true", default=False, help='Produce a ndiff format diff')
   parser.add_option("-l", "--lines", type="int", default=3, help='Set number of context lines (default 3)')
   (options, args) = parser.parse_args()
-  
+
   if len(args) == 0:
     parser.print_help()
     sys.exit(1)
   if len(args) != 2:
     parser.error("need to specify both a fromfile and tofile")
-  
+
   n = options.lines
   fromfile, tofile = args
-  
+
   fromdate = time.ctime(os.stat(fromfile).st_mtime)
   todate = time.ctime(os.stat(tofile).st_mtime)
   if sys.platform == 'win32':
@@ -86,17 +110,18 @@ def main():
     fromlines = open(fromfile, 'r' if sys.version_info >= (3, 4) else 'U').readlines()
     tolines = open(tofile, 'r' if sys.version_info >= (3, 4) else 'U').readlines()
 
-  nows_fromlines = filter(fromlines, True)
-  nows_tolines = filter(tolines, True)
+  lineFilter = LineFilter()
+  nows_fromlines = lineFilter.filter(fromlines, True)
+  nows_tolines = lineFilter.filter(tolines, True)
 
   check = difflib.context_diff(nows_fromlines, nows_tolines)
   try:
-    first = next(check)
+    _ = next(check)
   except StopIteration:
     sys.exit(0)
 
-  fromlines = filter(fromlines, False)
-  tolines = filter(tolines, False)
+  fromlines = lineFilter.filter(fromlines, False)
+  tolines = lineFilter.filter(tolines, False)
 
   if options.u:
     diff = difflib.unified_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)
@@ -106,12 +131,14 @@ def main():
     diff = difflib.HtmlDiff().make_file(fromlines,tolines,fromfile,tofile,context=options.c,numlines=n)
   else:
     diff = difflib.context_diff(fromlines, tolines, fromfile, tofile, fromdate, todate, n=n)
-  
+
   difflines = [line for line in diff]
   sys.stdout.writelines(difflines)
 
-  if difflines : sys.exit(1)
-  else         : sys.exit(0)
+  if difflines:
+    sys.exit(1)
+  else:
+    sys.exit(0)
 
 if __name__ == '__main__':
   main()