README

Add support for cloning with hardlinks on windows.

In order to use hardlinks, the win32file module is needed, and this is
present in ActivePython.  If it isn't present, or hardlinks are not supported
on the underlying filesystem, a regular copy is used.

When using hardlinks the biggest benefit is probably the saving in space,
but cloning can be much quicker.  For example cloning the Xen tree
(non trivial) without an update goes from about 95s to 15s.

Unix-like platforms should be unaffected, although should be more tolerant on
filesystems that don't support hard links.

(tweaked by mpm to deal with new copyfiles function)

--- hg.orig/mercurial/commands.py	2005-09-13 19:32:53.000000000 -0500
+++ hg/mercurial/commands.py	2005-09-14 12:11:34.000000000 -0500
@@ -620,10 +620,6 @@ def clone(ui, source, dest=None, **opts)

     if other.dev() != -1:
         abspath = os.path.abspath(source)
-        copyfile = (os.stat(dest).st_dev == other.dev()
-                    and getattr(os, 'link', None) or shutil.copy2)
-        if copyfile is not shutil.copy2:
-            ui.note("cloning by hardlink\n")

         # we use a lock here because if we race with commit, we can
         # end up with extra data in the cloned revlogs that's not
@@ -638,7 +634,7 @@ def clone(ui, source, dest=None, **opts)
         for f in files.split():
             src = os.path.join(source, ".hg", f)
             dst = os.path.join(dest, ".hg", f)
-            util.copyfiles(src, dst, copyfile)
+            util.copyfiles(src, dst)

         repo = hg.repository(ui, dest)

Index: hg/mercurial/util.py
===================================================================
--- hg.orig/mercurial/util.py	2005-09-08 00:15:25.000000000 -0500
+++ hg/mercurial/util.py	2005-09-14 12:16:49.000000000 -0500
@@ -12,7 +12,7 @@ platform-specific details from the core.

 import os, errno
 from demandload import *
-demandload(globals(), "re cStringIO")
+demandload(globals(), "re cStringIO shutil")

 def binary(s):
     """return true if a string is binary data using diff's heuristic"""
@@ -217,17 +217,28 @@ def rename(src, dst):
         os.unlink(dst)
         os.rename(src, dst)

-def copyfiles(src, dst, copyfile):
-    """Copy a directory tree, files are copied using 'copyfile'."""
+def copyfiles(src, dst, hardlink=None):
+    """Copy a directory tree using hardlinks if possible"""
+
+    if hardlink is None:
+        hardlink = (os.stat(src).st_dev ==
+                    os.stat(os.path.dirname(dst)).st_dev)

     if os.path.isdir(src):
         os.mkdir(dst)
         for name in os.listdir(src):
             srcname = os.path.join(src, name)
             dstname = os.path.join(dst, name)
-            copyfiles(srcname, dstname, copyfile)
+            copyfiles(srcname, dstname, hardlink)
     else:
-        copyfile(src, dst)
+        if hardlink:
+            try:
+                os_link(src, dst)
+            except:
+                hardlink = False
+                shutil.copy2(src, dst)
+        else:
+            shutil.copy2(src, dst)

 def opener(base):
     """
@@ -244,13 +255,13 @@ def opener(base):

         if mode[0] != "r":
             try:
-                s = os.stat(f)
+                nlink = nlinks(f)
             except OSError:
                 d = os.path.dirname(f)
                 if not os.path.isdir(d):
                     os.makedirs(d)
             else:
-                if s.st_nlink > 1:
+                if nlink > 1:
                     file(f + ".tmp", "wb").write(file(f, "rb").read())
                     rename(f+".tmp", f)

@@ -266,10 +277,41 @@ def _makelock_file(info, pathname):
 def _readlock_file(pathname):
     return file(pathname).read()

+def nlinks(pathname):
+    """Return number of hardlinks for the given file."""
+    return os.stat(pathname).st_nlink
+
+if hasattr(os, 'link'):
+    os_link = os.link
+else:
+    def os_link(src, dst):
+        raise OSError(0, "Hardlinks not supported")
+
 # Platform specific variants
 if os.name == 'nt':
     nulldev = 'NUL:'

+    try: # ActivePython can create hard links using win32file module
+        import win32file
+
+        def os_link(src, dst): # NB will only succeed on NTFS
+            win32file.CreateHardLink(dst, src)
+
+        def nlinks(pathname):
+            """Return number of hardlinks for the given file."""
+            try:
+                fh = win32file.CreateFile(pathname,
+                    win32file.GENERIC_READ, win32file.FILE_SHARE_READ,
+                    None, win32file.OPEN_EXISTING, 0, None)
+                res = win32file.GetFileInformationByHandle(fh)
+                fh.Close()
+                return res[7]
+            except:
+                return os.stat(pathname).st_nlink
+
+    except ImportError:
+        pass
+
     def is_exec(f, last):
         return last

MERCURIAL QUICK-START

Setting up Mercurial:

 Note: some distributions fails to include bits of distutils by
 default, you'll need python-dev to install. You'll also need a C
 compiler and a 3-way merge tool like merge, tkdiff, or kdiff3.

 First, unpack the source:

 $ tar xvzf mercurial-<ver>.tar.gz
 $ cd mercurial-<ver>

 To install system-wide:

 $ python setup.py install   # change python to python2.3 if 2.2 is default

 To install in your home directory (~/bin and ~/lib, actually), run:

 $ python2.3 setup.py install --home=~
 $ export PYTHONPATH=${HOME}/lib/python  # (or lib64/ on some systems)
 $ export PATH=${HOME}/bin:$PATH         # add these to your .bashrc

 And finally:

 $ hg                                    # test installation, show help

 If you get complaints about missing modules, you probably haven't set
 PYTHONPATH correctly.

Setting up a Mercurial project:

 $ cd project/
 $ hg init         # creates .hg
 $ hg addremove    # add all unknown files and remove all missing files
 $ hg commit       # commit all changes, edit changelog entry

 Mercurial will look for a file named .hgignore in the root of your
 repository which contains a set of regular expressions to ignore in
 file paths.

Branching and merging:

 $ hg clone linux linux-work    # create a new branch
 $ cd linux-work
 $ <make changes>
 $ hg commit
 $ cd ../linux
 $ hg pull ../linux-work     # pull changesets from linux-work
 $ hg update -m              # merge the new tip from linux-work into
                             # our working directory
 $ hg commit                 # commit the result of the merge

Importing patches:

 Fast:
 $ patch < ../p/foo.patch
 $ hg addremove
 $ hg commit

 Faster:
 $ patch < ../p/foo.patch
 $ hg commit `lsdiff -p1 ../p/foo.patch`

 Fastest:
 $ cat ../p/patchlist | xargs hg import -p1 -b ../p 

Exporting a patch:

 (make changes)
 $ hg commit
 $ hg tip
 28237:747a537bd090880c29eae861df4d81b245aa0190
 $ hg export 28237 > foo.patch    # export changeset 28237

Network support:

 # pull from the primary Mercurial repo
 foo$ hg clone http://selenic.com/hg/ 
 foo$ cd hg

 # export your current repo via HTTP with browsable interface
 foo$ hg serve -n "My repo" -p 80
 
 # pushing changes to a remote repo with SSH
 foo$ hg push ssh://[e-mail]/~/hg/

 # merge changes from a remote machine
 bar$ hg pull http://foo/
 bar$ hg update -m        # merge changes into your working directory

 # Set up a CGI server on your webserver
 foo$ cp hgweb.cgi ~/public_html/hg/index.cgi
 foo$ emacs ~/public_html/hg/index.cgi # adjust the defaults

For more info:

 Documentation in doc/
 Mercurial website at http://selenic.com/mercurial
 Mercurial wiki at http://selenic.com/mercurial/wiki