Rename to blueprint-compiler

This isn't an official GTK project so better to avoid using "GTK" in the
name.

blueprintcompiler/xml_reader.py

@@ -0,0 +1,93 @@
+# xml_reader.py
+#
+# Copyright 2021 James Westman <james@jwestman.net>
+#
+# This file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 3 of the
+# License, or (at your option) any later version.
+#
+# This file is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# SPDX-License-Identifier: LGPL-3.0-or-later
+
+
+from collections import defaultdict
+from xml import sax
+
+from .utils import lazy_prop
+
+
+# To speed up parsing, we ignore all tags except these
+PARSE_GIR = set([
+    "repository", "namespace", "class", "interface", "property", "glib:signal",
+    "include", "implements", "type", "parameter", "parameters", "enumeration",
+    "member",
+])
+
+
+class Element:
+    def __init__(self, tag, attrs):
+        self.tag = tag
+        self.attrs = attrs
+        self.children = defaultdict(list)
+        self.cdata_chunks = []
+
+    @lazy_prop
+    def cdata(self):
+        return ''.join(self.cdata_chunks)
+
+    def get_elements(self, name):
+        return self.children.get(name, [])
+
+    def __getitem__(self, key):
+        return self.attrs.get(key)
+
+
+class Handler(sax.handler.ContentHandler):
+    def __init__(self, parse_type):
+        self.root = None
+        self.stack = []
+        self.skipping = 0
+        self._interesting_elements = parse_type
+
+    def startElement(self, name, attrs):
+        if name not in self._interesting_elements:
+            self.skipping += 1
+        if self.skipping > 0:
+            return
+
+        element = Element(name, attrs.copy())
+
+        if len(self.stack):
+            last = self.stack[-1]
+            last.children[name].append(element)
+        else:
+            self.root = element
+
+        self.stack.append(element)
+
+
+    def endElement(self, name):
+        if self.skipping == 0:
+            self.stack.pop()
+        if name not in self._interesting_elements:
+            self.skipping -= 1
+
+    def characters(self, content):
+        if not self.skipping:
+            self.stack[-1].cdata_chunks.append(content)
+
+
+def parse(filename, parse_type):
+    parser = sax.make_parser()
+    handler = Handler(parse_type)
+    parser.setContentHandler(handler)
+    parser.parse(filename)
+    return handler.root