total mess: some random experiments with images and lqc's dvcs

[redakcja.git] / apps / wiki_img / nice_diff.py

diff --git a/apps/wiki_img/nice_diff.py b/apps/wiki_img/nice_diff.py
new file mode 100644 (file)
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+++ b/apps/wiki_img/nice_diff.py
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+# -*- coding: utf-8 -*-
+#
+# This file is part of FNP-Redakcja, licensed under GNU Affero GPLv3 or later.
+# Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
+#
+import difflib
+import re
+from collections import deque
+
+from django.template.loader import render_to_string
+from django.utils.html import escape as html_escape
+
+DIFF_RE = re.compile(r"""\x00([+^-])""", re.UNICODE)
+NAMES = {'+': 'added', '-': 'removed', '^': 'changed'}
+
+
+def diff_replace(match):
+    return """<span class="diff_mark diff_mark_%s">""" % NAMES[match.group(1)]
+
+
+def filter_line(line):
+    return  DIFF_RE.sub(diff_replace, html_escape(line)).replace('\x01', '</span>')
+
+
+def format_changeset(a, b, change):
+    return (a[0], filter_line(a[1]), b[0], filter_line(b[1]), change)
+
+
+def html_diff_table(la, lb, context=None):
+    all_changes = difflib._mdiff(la, lb)
+
+    if context is None:
+        changes = (format_changeset(*c) for c in all_changes)
+    else:
+        changes = []
+        q = deque()
+        after_change = False
+
+        for changeset in all_changes:
+            q.append(changeset)
+
+            if changeset[2]:
+                after_change = True
+                if not after_change:
+                    changes.append((0, '-----', 0, '-----', False))
+                changes.extend(format_changeset(*c) for c in q)
+                q.clear()
+            else:
+                if len(q) == context and after_change:
+                    changes.extend(format_changeset(*c) for c in q)
+                    q.clear()
+                    after_change = False
+                elif len(q) > context:
+                    q.popleft()
+
+    return render_to_string("wiki/diff_table.html", {
+        "changes": changes,
+    })
+
+
+__all__ = ['html_diff_table']