[gtk-doc] mkhtml2: add converter for 'preface' chunks

[Stefan Sauer <stefkost src gnome org>]

commit 0ae9950c247f71b6db7c4bc25ea0f5ef1521227c
Author: Stefan Sauer <ensonic users sf net>
Date:   Sun Mar 25 19:55:35 2018 +0200

    mkhtml2: add converter for 'preface' chunks

 gtkdoc/mkhtml2.py |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
---
diff --git a/gtkdoc/mkhtml2.py b/gtkdoc/mkhtml2.py
index 1b5d29f..3477c6d 100644
--- a/gtkdoc/mkhtml2.py
+++ b/gtkdoc/mkhtml2.py
@@ -873,6 +873,25 @@ def convert_index(ctx):
     return result
 
 
+def convert_preface(ctx):
+    node = ctx['node']
+    result = [
+        HTML_HEADER % (node.title + ": " + node.root.title, generate_head_links(ctx)),
+        generate_basic_nav(ctx),
+        '<div class="preface">',
+    ]
+    title = node.xml.find('title')
+    if title is not None:
+        result.append('<div class="titlepage"><h2 class="title"><a name="%s"></a>%s</h2></div>' % (
+            get_id(node), title.text))
+        node.xml.remove(title)
+    convert_inner(ctx, node.xml, result)
+    result.append("""</div>
+</body>
+</html>""")
+    return result
+
+
 def convert_refentry(ctx):
     node = ctx['node']
     node_id = get_id(node)
@@ -909,6 +928,7 @@ convert_chunks = {
     'book': convert_book,
     'chapter': convert_chapter,
     'index': convert_index,
+    'preface': convert_preface,
     'refentry': convert_refentry,
 }