# HG changeset patch
# User Durham Goode <durham@fb.com>
# Date 1491854867 25200
# Node ID 94c1d3c1aea2f6b9021616b4e64bc4143787b6c0
# Parent  b6d792a9bd116969235f1eb21e25d244351a5549
treemanifest: add walksubtrees api

Adds a new function to treemanifest that allows walking over the directories in
the tree. Currently it only accepts a matcher to prune the walk, but in the
future it will also accept a list of trees and will only walk over subtrees that
differ from the versions in the list. This will be useful for identifying what
parts of the tree are new to this revision, which is useful when deciding the
minimal set of trees to send to a client given that they have a certain tree
already.

Since this is intended for an extension to use, the only current consumer is a
test. In the future this function may be useful for implementing other
algorithms like diff and changegroup generation.

diff -r b6d792a9bd11 -r 94c1d3c1aea2 mercurial/manifest.py
--- a/mercurial/manifest.py	Tue Apr 11 23:12:14 2017 +0900
+++ b/mercurial/manifest.py	Mon Apr 10 13:07:47 2017 -0700
@@ -1155,6 +1155,22 @@
                 subp1, subp2 = subp2, subp1
             writesubtree(subm, subp1, subp2)
 
+    def walksubtrees(self, matcher=None):
+        """Returns an iterator of the subtrees of this manifest, including this
+        manifest itself.
+
+        If `matcher` is provided, it only returns subtrees that match.
+        """
+        if matcher and not matcher.visitdir(self._dir[:-1] or '.'):
+            return
+        if not matcher or matcher(self._dir[:-1]):
+            yield self
+
+        self._load()
+        for d, subm in self._dirs.iteritems():
+            for subtree in subm.walksubtrees(matcher=matcher):
+                yield subtree
+
 class manifestrevlog(revlog.revlog):
     '''A revlog that stores manifest texts. This is responsible for caching the
     full-text manifest contents.
diff -r b6d792a9bd11 -r 94c1d3c1aea2 tests/test-manifest.py
--- a/tests/test-manifest.py	Tue Apr 11 23:12:14 2017 +0900
+++ b/tests/test-manifest.py	Mon Apr 10 13:07:47 2017 -0700
@@ -467,5 +467,21 @@
     def parsemanifest(self, text):
         return manifestmod.treemanifest('', text)
 
+    def testWalkSubtrees(self):
+        m = self.parsemanifest(A_DEEPER_MANIFEST)
+
+        dirs = [s._dir for s in m.walksubtrees()]
+        self.assertEqual(
+            sorted(['', 'a/', 'a/c/', 'a/d/', 'a/b/', 'a/b/c/', 'a/b/d/']),
+            sorted(dirs)
+        )
+
+        match = matchmod.match('/', '', ['path:a/b/'])
+        dirs = [s._dir for s in m.walksubtrees(matcher=match)]
+        self.assertEqual(
+            sorted(['a/b/', 'a/b/c/', 'a/b/d/']),
+            sorted(dirs)
+        )
+
 if __name__ == '__main__':
     silenttestrunner.main(__name__)