xmlwriter: move collect_attributes() back to a Python implementation

This reverts f345916405d94829696985 and related. The commit states that
both versions are about the same in performance, but the C version is more code and
harder to maintain. It also states that the behaviour re invalid control
characters is better with the C version which produces entities. But those
make any Python xml parser fail, which given that most of our tooling is Python,
doesn't seem better to me, see #135.

1 files changed, 37 insertions, 7 deletions

diff --git a/giscanner/xmlwriter.py b/giscanner/xmlwriter.py
index f79362a1..a65fc40c 100755
--- a/giscanner/xmlwriter.py
+++ b/giscanner/xmlwriter.py
@@ -28,9 +28,7 @@ import os
 import sys
 
 from contextlib import contextmanager
-from xml.sax.saxutils import escape
-
-from .libtoolimporter import LibtoolImporter
+from xml.sax.saxutils import escape, quoteattr
 
 if sys.version_info.major < 3:
     from StringIO import StringIO
@@ -39,11 +37,43 @@ else:
     unicode = str
 
 
-with LibtoolImporter(None, None):
-    if 'UNINSTALLED_INTROSPECTION_SRCDIR' in os.environ:
-        from _giscanner import collect_attributes
+def _calc_attrs_length(attributes, indent, self_indent):
+    if indent == -1:
+        return -1
+    attr_length = 0
+    for attr, value in attributes:
+        # FIXME: actually, if we have attributes with None as value this
+        # should be considered a bug and raise an error. We are just
+        # ignoring them here while we fix GIRParser to create the right
+        # ast with the correct attributes.
+        if value is None:
+            continue
+        attr_length += 2 + len(attr) + len(quoteattr(value))
+    return attr_length + indent + self_indent
+
+
+def collect_attributes(tag_name, attributes, self_indent, self_indent_char, indent=-1):
+    if not attributes:
+        return ''
+    if _calc_attrs_length(attributes, indent, self_indent) > 79:
+        indent_len = self_indent + len(tag_name) + 1
     else:
-        from giscanner._giscanner import collect_attributes
+        indent_len = 0
+    first = True
+    attr_value = ''
+    for attr, value in attributes:
+        # FIXME: actually, if we have attributes with None as value this
+        # should be considered a bug and raise an error. We are just
+        # ignoring them here while we fix GIRParser to create the right
+        # ast with the correct attributes.
+        if value is None:
+            continue
+        if indent_len and not first:
+            attr_value += '\n%s' % (self_indent_char * indent_len)
+        attr_value += ' %s=%s' % (attr, quoteattr(value))
+        if first:
+            first = False
+    return attr_value
 
 
 def build_xml_tag(tag_name, attributes=None, data=None, self_indent=0,