giscanner: use SqlAlchemy's OrderedDict implementation

g-ir-scanner can be a bit on the slow side. While true we
now do a bit more work parsing GTK-Doc comment blocks and
more is still to come, one of the biggest hotspots besides
what's going on in _giscanner.SourceScanner() comes from
the OrderedDict implementations we have been using.

For example, time needed to build Gtk-3.0.gir on a relatively
slow machine using "python2 -m cProfile -o $prefix/bin/g-ir-scanner ...":

1) Our original DictMixin sublass:
     92,79867 seconds
2) Python's collections.OrderedDict class:
     88,65786 seconds
3) Larosa/Foord implementation from http://www.voidspace.org.uk/python/odict.html :
     71,64323 seconds
4) SqlAlchemy's implementation:
     66,12449 seconds

Looks like we have a clear winner with the SqlAclchemy
implementation, which comes in at around 20 seconds
without profiling on the same machine. Not bad.

https://bugzilla.gnome.org/show_bug.cgi?id=697620

1 files changed, 2 insertions, 2 deletions

diff --git a/giscanner/ast.py b/giscanner/ast.py
index 58540912..d307b553 100644
--- a/giscanner/ast.py
+++ b/giscanner/ast.py
@@ -25,7 +25,7 @@ from itertools import chain
 from . import message
 
 from .message import Position
-from .odict import odict
+from .odict import OrderedDict
 from .utils import to_underscores
 
 class Type(object):
@@ -367,7 +367,7 @@ class Namespace(object):
             self.symbol_prefixes = [to_underscores(p).lower() for p in ps]
         # cache upper-cased versions
         self._ucase_symbol_prefixes = [p.upper() for p in self.symbol_prefixes]
-        self.names = odict() # Maps from GIName -> node
+        self.names = OrderedDict() # Maps from GIName -> node
         self.aliases = {} # Maps from GIName -> GIName
         self.type_names = {} # Maps from GTName -> node
         self.ctypes = {} # Maps from CType -> node