1 files changed, 113 insertions, 0 deletions
diff --git a/include_server/mirror_path.py b/include_server/mirror_path.py
new file mode 100755
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+++ b/include_server/mirror_path.py
@@ -0,0 +1,113 @@
+#!/usr/bin/python2.4
+
+# Copyright 2007 Google Inc.
+# 
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+# """Memoizing, piecemeal mirroring of directory and link structure."""
+
+__author__ = "Nils Klarlund"
+
+
+import os
+import os.path
+
+import cache_basics
+
+class MirrorPath(object):
+  """Make a caching structure for copying all parts of the paths that
+  method DoPath is called with. This includes replication of symbolic
+  links.  But the targets of symbolic links are absolutized: they are
+  replaced by the realpath of the original target, whether this target
+  was relative or absolute."""
+
+  def __init__(self,
+	       simple_build_stat,
+	       canonical_path):
+    """Constructor.
+
+    Arguments:
+      simple_build_stat: object of type SimpleBuildStat
+      canonical_path: function of type CanonicalPath
+    """
+    assert isinstance(simple_build_stat, cache_basics.SimpleBuildStat)
+    assert isinstance(canonical_path, cache_basics.CanonicalPath)
+    # All links encountered so far.
+    self.links = []
+    # We cache tuples (filepath, current_dir_idx) for which we've already fixed
+    # up the symbolic links.
+    self.link_stat = set([])
+    # Usual abbreviations.
+    self.simple_build_stat = simple_build_stat
+    self.canonical_path = canonical_path
+
+  def Links(self):
+    """Return the list of symbolic links created."""
+    return self.links
+
+  def DoPath(self, filepath, current_dir_idx, root):
+    """Mirror the parts of filepath not yet created under root.
+
+    Arguments:
+      filepath: a string, which is relative or absolute filename
+      current_dir_idx: a directory index
+      root: a string denoting an absolute path for an existing directory
+    """
+    assert isinstance(filepath, str)
+    assert isinstance(current_dir_idx, int)
+    assert isinstance(root, str)
+    assert root[0] == '/' and root[-1] != '/'
+    assert os.path.isdir(root), root
+
+    link_stat = self.link_stat
+    lookup = self.simple_build_stat.Lookup
+    # Working from the end (in the hope that a cache lookup will reveal
+    # the futility of further work), make sure that intermediate
+    # destinations exist, and replicate symbolic links where necessary.
+    while filepath and filepath != '/':
+      if (filepath, current_dir_idx) in link_stat:
+	# Filepath is already mirrored
+	return
+      link_stat.add((filepath, current_dir_idx))
+      # Process suffix of filepath by
+      # - making sure that the mirrored real path of the prefix exists,
+      # - and that the suffix if a symbolic link
+      # is replicated as a symbolic link.
+      assert filepath[-1] != '/', filepath
+
+      # Now identify the potential symbolic link at the end of filepath
+      (prefix_filepath, suffix) = os.path.split(filepath)
+      # Calculate the real position of the destination of the prefix
+      prefix_real = self.canonical_path.Canonicalize(prefix_filepath)
+
+      if prefix_real == '/': prefix_real = ''
+
+      # And, its counterpart under root
+      root_prefix_real = root + prefix_real
+
+      # Make sure that root_prefix_real is there
+      if not lookup(root_prefix_real):
+	if not os.path.isdir(root_prefix_real):
+	  os.makedirs(root_prefix_real)
+	self.simple_build_stat.cache[root_prefix_real] = True
+
+      assert os.path.isdir(root_prefix_real)
+      # Create the mirrored symbolic link if applicable
+      if os.path.islink(filepath):
+	link_name = root_prefix_real + '/' + suffix
+	if not os.path.exists(link_name):
+	  os.symlink(self.canonical_path.Canonicalize(filepath), link_name)
+	  self.links.append(link_name)
+      filepath = prefix_filepath