# HG changeset patch
# User Mads Kiilerich <mads@kiilerich.com>
# Date 2017-10-03 00:14:40
# Node ID 52e756b40a2b46c598cd22128ecef41052be3ef1
# Parent  e85f08375dc67d17ed41d5dea8a8bcb2bb52cf00

diffs: do check of cut_off_limit on the raw diff before any parsing and allocation

This redefines the exact meaning of cut_off_limit but it will still be
approximately the same thing. It makes it more a limitation of what amount of
work should be done, more than how much html should be outputted.

It could make sense to push the limit further back to vcs to also prevent
computing or allocating memory for huge diffs.

diff --git a/kallithea/lib/diffs.py b/kallithea/lib/diffs.py
--- a/kallithea/lib/diffs.py
+++ b/kallithea/lib/diffs.py
@@ -137,10 +137,6 @@ CHMOD_FILENODE = 6
 BIN_FILENODE = 7
 
 
-class DiffLimitExceeded(Exception):
-    pass
-
-
 class DiffProcessor(object):
     """
     Give it a unified or git diff and it returns a list of the files that were
@@ -204,24 +200,15 @@ class DiffProcessor(object):
         self._diff = diff
         self.adds = 0
         self.removes = 0
-        # calculate diff size
         self.diff_limit = diff_limit
-        self.cur_diff_size = 0
         self.limited_diff = False
         self.vcs = vcs
         self.parsed = self._parse_gitdiff(inline_diff=inline_diff)
 
     def _escaper(self, string):
         """
-        Do HTML escaping/markup and check the diff limit
+        Do HTML escaping/markup
         """
-        self.cur_diff_size += len(string)
-
-        # escaper gets iterated on each .next() call and it checks if each
-        # parsed line doesn't exceed the diff limit
-        if self.diff_limit is not None and self.cur_diff_size > self.diff_limit:
-            raise DiffLimitExceeded('Diff Limit Exceeded')
-
         def substitute(m):
             groups = m.groups()
             if groups[0]:
@@ -304,6 +291,10 @@ class DiffProcessor(object):
         starts.append(len(self._diff))
 
         for start, end in zip(starts, starts[1:]):
+            if self.diff_limit and end > self.diff_limit:
+                self.limited_diff = True
+                continue
+
             head, diff_lines = self._get_header(buffer(self._diff, start, end - start))
 
             op = None
@@ -363,18 +354,13 @@ class DiffProcessor(object):
 
             # a real non-binary diff
             if head['a_file'] or head['b_file']:
-                try:
-                    chunks, added, deleted = self._parse_lines(diff_lines)
-                    stats['binary'] = False
-                    stats['added'] = added
-                    stats['deleted'] = deleted
-                    # explicit mark that it's a modified file
-                    if op == 'M':
-                        stats['ops'][MOD_FILENODE] = 'modified file'
-
-                except DiffLimitExceeded:
-                    self.limited_diff = True
-                    break
+                chunks, added, deleted = self._parse_lines(diff_lines)
+                stats['binary'] = False
+                stats['added'] = added
+                stats['deleted'] = deleted
+                # explicit mark that it's a modified file
+                if op == 'M':
+                    stats['ops'][MOD_FILENODE] = 'modified file'
             else:  # Git binary patch (or empty diff)
                 # Git binary patch
                 if head['bin_patch']: