# HG changeset patch
# User Kyle Lippincott <spectral@google.com>
# Date 1486897598 28800
# Node ID 8b83b626fb1e9df49d7bb5ded36e986ed4455d83
# Parent  b7e073ae44c4312d96ecdf17b36b575794fc4e54
ui: remove urllib2 from being imported early

Before this change, urllib2 was brought in when constructing the ui object, and
that added ~5ms on my Linux workstation to the hg startup time for every
command, bringing the time for 'HGRCPATH=/dev/null hg root' from 46ms to 40ms.

Now, we construct a single proxy object per initial ui creation (so that if the
ui is copied they share the object), but defer the actual instantiation of it
and the import of urllib2 until it's needed.

# no-check-commit

diff -r b7e073ae44c4 -r 8b83b626fb1e mercurial/ui.py
--- a/mercurial/ui.py	Mon Feb 06 23:57:32 2017 -0500
+++ b/mercurial/ui.py	Sun Feb 12 03:06:38 2017 -0800
@@ -94,6 +94,24 @@
 # pager =""",
 }
 
+
+class httppasswordmgrdbproxy(object):
+    """Delays loading urllib2 until it's needed."""
+    def __init__(self):
+        self._mgr = None
+
+    def _get_mgr(self):
+        if self._mgr is None:
+            self._mgr = urlreq.httppasswordmgrwithdefaultrealm()
+        return self._mgr
+
+    def add_password(self, *args, **kwargs):
+        return self._get_mgr().add_password(*args, **kwargs)
+
+    def find_user_password(self, *args, **kwargs):
+        return self._get_mgr().find_user_password(*args, **kwargs)
+
+
 class ui(object):
     def __init__(self, src=None):
         """Create a fresh new ui object if no src given
@@ -145,7 +163,7 @@
             # shared read-only environment
             self.environ = encoding.environ
 
-            self.httppasswordmgrdb = urlreq.httppasswordmgrwithdefaultrealm()
+            self.httppasswordmgrdb = httppasswordmgrdbproxy()
 
         allowed = self.configlist('experimental', 'exportableenviron')
         if '*' in allowed:
@@ -172,7 +190,7 @@
         """Clear internal state that shouldn't persist across commands"""
         if self._progbar:
             self._progbar.resetstate()  # reset last-print time of progress bar
-        self.httppasswordmgrdb = urlreq.httppasswordmgrwithdefaultrealm()
+        self.httppasswordmgrdb = httppasswordmgrdbproxy()
 
     def formatter(self, topic, opts):
         return formatter.formatter(self, topic, opts)