Issue 2177: Dir get_contents changed to return list of signatures

2 files changed, 45 insertions, 3 deletions

diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index a2c7244..eda6e71 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -1593,9 +1593,24 @@ class Dir(Base):
         return None
 
     def get_contents(self):
-        """Return aggregate contents of all our children."""
-        contents = map(lambda n: n.get_contents(), self.children())
-        return  string.join(contents, '')
+        """Return content signatures and names of all our children
+        separated by new-lines. Ensure that the nodes are sorted."""
+        contents = []
+        name_cmp = lambda a, b: cmp(a.name, b.name)
+        sorted_children = self.children()[:]
+        sorted_children.sort(name_cmp)        
+        for node in sorted_children:
+            contents.append('%s %s\n' % (node.get_csig(), node.name))
+        return string.join(contents, '')
+
+    def get_csig(self):
+        """Compute the content signature for Directory nodes. In
+        general, this is not needed and the content signature is not
+        stored in the DirNodeInfo. However, if get_contents on a Dir
+        node is called which has a child directory, the child
+        directory should return the hash of its contents."""
+        contents = self.get_contents()
+        return SCons.Util.MD5signature(contents)
 
     def do_duplicate(self, src):
         pass
diff --git a/src/engine/SCons/Node/FSTests.py b/src/engine/SCons/Node/FSTests.py
index cfdc978..9d3cabb 100644
--- a/src/engine/SCons/Node/FSTests.py
+++ b/src/engine/SCons/Node/FSTests.py
@@ -1689,6 +1689,33 @@ class DirTestCase(_tempdirTestCase):
                         os.path.join('ddd', 'f2'),
                         os.path.join('ddd', 'f3')], kids
 
+    def test_get_contents(self):
+        """Test getting the contents for a directory.
+        """
+        test = self.test
+
+        test.subdir('d')
+        test.write(['d', 'g'], "67890\n")
+        test.write(['d', 'f'], "12345\n")
+        test.subdir(['d','sub'])
+        test.write(['d', 'sub','h'], "abcdef\n")
+        test.subdir(['d','empty'])
+
+        d = self.fs.Dir('d')
+        g = self.fs.File(os.path.join('d', 'g'))
+        f = self.fs.File(os.path.join('d', 'f'))
+        h = self.fs.File(os.path.join('d', 'sub', 'h'))
+        e = self.fs.Dir(os.path.join('d', 'empty'))
+        s = self.fs.Dir(os.path.join('d', 'sub'))
+
+        files = d.get_contents().split('\n')
+
+        assert e.get_contents() == '', e.get_contents()
+        assert e.get_csig()+" empty" == files[0], files
+        assert f.get_csig()+" f" == files[1], files
+        assert g.get_csig()+" g" == files[2], files
+        assert s.get_csig()+" sub" == files[3], files
+
     def test_implicit_re_scans(self):
         """Test that adding entries causes a directory to be re-scanned
         """