[OE-core] [PATCH 19/22] sstate/path.py: Add copyhardlinktree() function and use for performance optimisation

[Richard Purdie]

Add a function which copys a tree as a set of hardlinks to the original
files, then use this in sstate to reduce some of the overhead of sstate
package creation since the file isn't actually copied.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
 meta/classes/sstate.bbclass |    4 ++--
 meta/lib/oe/path.py         |    4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index a79d2b5..6f77bb9 100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -458,14 +458,14 @@ def sstate_package(ss, d):
                 dstpath = srcpath.replace(state[1], sstatebuild + state[0])
                 make_relative_symlink(srcpath, dstpath, d)
         bb.debug(2, "Preparing tree %s for packaging at %s" % (state[1], sstatebuild + state[0]))
-        oe.path.copytree(state[1], sstatebuild + state[0])
+        oe.path.copyhardlinktree(state[1], sstatebuild + state[0])
 
     workdir = d.getVar('WORKDIR', True)
     for plain in ss['plaindirs']:
         pdir = plain.replace(workdir, sstatebuild)
         bb.mkdirhier(plain)
         bb.mkdirhier(pdir)
-        oe.path.copytree(plain, pdir)
+        oe.path.copyhardlinktree(plain, pdir)
 
     d.setVar('SSTATE_BUILDDIR', sstatebuild)
     d.setVar('SSTATE_PKG', sstatepkg)
diff --git a/meta/lib/oe/path.py b/meta/lib/oe/path.py
index 7197b23..11d4694 100644
--- a/meta/lib/oe/path.py
+++ b/meta/lib/oe/path.py
@@ -83,6 +83,10 @@ def copytree(src, dst):
     cmd = 'tar -cf - -C %s -ps . | tar -xf - -C %s' % (src, dst)
     check_output(cmd, shell=True, stderr=subprocess.STDOUT)
 
+def copyhardlinktree(src, dst):
+    bb.utils.mkdirhier(dst)
+    cmd = 'cp -al %s %s' % (src, dst)
+    check_output(cmd, shell=True, stderr=subprocess.STDOUT)
 
 def remove(path, recurse=True):
     """Equivalent to rm -f or rm -rf"""
-- 
1.7.10.4