Optimize dblink.isowner() to use fewer stat calls by doing a basename

comparison to try and eliminate the file before resorting to inode
comparison. This speeds up the `portageq owners` command as well as
the search that is done when collision-protect finds a collision.
(trunk r9363)

svn path=/main/branches/2.1.2/; revision=9534

diff --git a/pym/portage.py b/pym/portage.py
index b8da8d9b6e42a6fc4cfbc9025fcb40c27da1cb1a..d2edcf0f12e31e44c204f7ae83924ed1a1075032 100644 (file)
--- a/pym/portage.py
+++ b/pym/portage.py
@@ -8037,6 +8037,7 @@ class dblink:
                self._installed_instance = None
                self.contentscache = None
                self._contents_inodes = None
+               self._contents_basenames = None
 
        def lockdb(self):
                if self._lock_vdb:
@@ -8605,6 +8606,16 @@ class dblink:
                if pkgfiles and destfile in pkgfiles:
                        return True
                if pkgfiles:
+                       basename = os.path.basename(destfile)
+                       if self._contents_basenames is None:
+                               self._contents_basenames = set(
+                                       os.path.basename(x) for x in pkgfiles)
+                       if basename not in self._contents_basenames:
+                               # This is a shortcut that, in most cases, allows us to
+                               # eliminate this package as an owner without the need
+                               # to examine inode numbers of parent directories.
+                               return False
+
                        # Use stat rather than lstat since we want to follow
                        # any symlinks to the real parent directory.
                        parent_path = os.path.dirname(destfile)
@@ -8640,7 +8651,6 @@ class dblink:
                        p_path_list = self._contents_inodes.get(
                                (parent_stat.st_dev, parent_stat.st_ino))
                        if p_path_list:
-                               basename = os.path.basename(destfile)
                                for p_path in p_path_list:
                                        x = os.path.join(p_path, basename)
                                        if x in pkgfiles:
@@ -9106,6 +9116,7 @@ class dblink:
                for dblnk in others_in_slot:
                        dblnk.contentscache = None
                        dblnk._contents_inodes = None
+                       dblnk._contents_basenames = None
 
                # If portage is reinstalling itself, remove the old
                # version now since we want to use the temporary