implement demand loading hack

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implement demand loading hack

This attempts to speed up start-up times without pushing imports down
into local scopes.

manifest hash: f9c18897e67f7872b44f5c89bdde00edfc3628ce
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mercurial/demandload.py

@@ -0,0 +1,15 b''
+def demandload(scope, modules):
+    class d:
+        def __getattr__(self, name):
+            mod = self.__dict__["mod"]
+            scope = self.__dict__["scope"]
+            scope[mod] = __import__(mod, scope, scope, [])
+            return getattr(scope[mod], name)
+
+    for m in modules.split():
+        dl = d()
+        dl.mod = m
+        dl.scope = scope
+        scope[m] = dl
+
+

mercurial/commands.py

@@ -5,8 +5,10 b''
 # This software may be used and distributed according to the terms
 # of the GNU General Public License, incorporated herein by reference.
 
-import os, re, sys, signal, time, mdiff
-from mercurial import fancyopts, ui, hg
+import os, re, sys, signal
+import fancyopts, ui, hg
+from demandload import *
+demandload(globals(), "mdiff time hgweb traceback")
 
 class UnknownCommand(Exception): pass
 
@@ -397,7 +399,6 b' def remove(ui, repo, file, *files):'
 
 def serve(ui, repo, **opts):
     """export the repository via HTTP"""
-    from mercurial import hgweb
     hgweb.server(repo.root, opts["name"], opts["templates"],
                  opts["address"], opts["port"])
     
@@ -594,7 +595,6 b' def dispatch(args):'
         else:
             raise
     except TypeError, inst:
-        import traceback
         # was this an argument error?
         tb = traceback.extract_tb(sys.exc_info()[2])
         if len(tb) > 2: # no

mercurial/hg.py

@@ -6,10 +6,10 b''
 # of the GNU General Public License, incorporated herein by reference.
 
 import sys, struct, os
-from mercurial import lock
-from mercurial.transaction import *
-from mercurial.revlog import *
-from difflib import SequenceMatcher
+from revlog import *
+from demandload import *
+demandload(globals(), "re lock urllib urllib2 transaction time socket")
+demandload(globals(), "tempfile byterange difflib")
 
 class filelog(revlog):
     def __init__(self, opener, path):
@@ -32,7 +32,7 b' class filelog(revlog):'
 
         def pair(parent, child):
             new = []
-            sm = SequenceMatcher(None, strip(parent), strip(child))
+            sm = difflib.SequenceMatcher(None, strip(parent), strip(child))
             for o, m, n, s, t in sm.get_opcodes():
                 if o == 'equal':
                     new += parent[m:n]
@@ -138,7 +138,6 b' class changelog(revlog):'
 
     def add(self, manifest, list, desc, transaction, p1=None, p2=None,
                   user=None, date=None):
-        import socket, time
         user = (user or
                 os.environ.get("HGUSER") or
                 os.environ.get("EMAIL") or
@@ -310,7 +309,6 b' class localrepository:'
             self.dirstate = dirstate(self.opener, ui, self.root)
 
     def ignore(self, f):
-        import re
         if self.ignorelist is None:
             self.ignorelist = []
             try:
@@ -358,14 +356,15 b' class localrepository:'
         # save dirstate for undo
         ds = self.opener("dirstate").read()
         self.opener("undo.dirstate", "w").write(ds)
-        return transaction(self.opener, self.join("journal"),
-                           self.join("undo"))
+        
+        return transaction.transaction(self.opener, self.join("journal"),
+                                       self.join("undo"))
 
     def recover(self):
         lock = self.lock()
         if os.path.exists(self.join("recover")):
             self.ui.status("attempting to rollback interrupted transaction\n")
-            return rollback(self.opener, self.join("recover"))
+            return transaction.rollback(self.opener, self.join("recover"))
         else:
             self.ui.warn("no interrupted transaction available\n")
 
@@ -373,7 +372,7 b' class localrepository:'
         lock = self.lock()
         if os.path.exists(self.join("undo")):
             self.ui.status("attempting to rollback last transaction\n")
-            rollback(self.opener, self.join("undo"))
+            transaction.rollback(self.opener, self.join("undo"))
             self.dirstate = None
             os.rename(self.join("undo.dirstate"), self.join("dirstate"))
             self.dirstate = dirstate(self.opener, self.ui, self.root)
@@ -952,8 +951,6 b' class localrepository:'
     def merge3(self, fn, my, other):
         """perform a 3-way merge in the working directory"""
 
-        import tempfile
-        
         def temp(prefix, node):
             pre = "%s~%s." % (os.path.basename(fn), prefix)
             (fd, name) = tempfile.mkstemp("", pre)
@@ -1164,14 +1161,10 b' class remoterepository:'
 
 def repository(ui, path=None, create=0):
     if path and path[:7] == "http://":
-        import urllib, urllib2
         return remoterepository(ui, path)
     if path and path[:5] == "hg://":
-        import urllib, urllib2
         return remoterepository(ui, path.replace("hg://", "http://"))
     if path and path[:11] == "old-http://":
-        import urllib, urllib2
-        from mercurial import byterange
         return localrepository(ui, path.replace("old-http://", "http://"))
     else:
         return localrepository(ui, path, create)