tests/test-diff-antipatience.t

store: introduce _matchtrackedpath() and use it to filter store files

This patch introduces a function to filter store files on the basis of the path
which they are tracking.

The function assumes that the entries can be of two types, 'meta/*' and 'data/*'
which means it will just work on revlog based storage and not with another
storage ways.

For the 'data/*' entries, we remove the 'data/' part and '.i/.d' part from the
beginning and the end then pass that to matcher.

For the 'meta/*' entries, we remove the 'meta/' and '/00manifest.(i/d)' part from
beginning and end then call matcher.visitdir() with it to make sure all the
parent directories are also downloaded.

Since the storage filtering for narrow stream clones is implemented with this
patch, we remove the un-implemented error message, add some more tests and add
the treemanifest case to tests too.

The tests demonstrate that it works correctly.

After this patch, we have now narrow stream clones working. Narrow stream clones
are a very important feature for large repositories who have good internet
connection because they use streamclones for cloning and if they do normal
narrow clone, that takes more time then a full streamclone. Also narrow-stream
clone will drastically speed up clone timings.

Differential Revision: https://phab.mercurial-scm.org/D5139

#testcases bdiff xdiff

#if xdiff
#require xdiff
  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > xdiff = true
  > EOF
#endif

Test case that makes use of the weakness of patience diff algorithm

  $ hg init
  >>> open('a', 'wb').write(('\n'.join(list('a' + 'x' * 10 + 'u' + 'x' * 30 + 'a\n'))).encode('ascii')) and None
  $ hg commit -m 1 -A a
  >>> open('a', 'wb').write(('\n'.join(list('b' + 'x' * 30 + 'u' + 'x' * 10 + 'b\n'))).encode('ascii')) and None
#if xdiff
  $ hg diff
  diff -r f0aeecb49805 a
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,4 +1,4 @@
  -a
  +b
   x
   x
   x
  @@ -9,7 +9,6 @@
   x
   x
   x
  -u
   x
   x
   x
  @@ -30,6 +29,7 @@
   x
   x
   x
  +u
   x
   x
   x
  @@ -40,5 +40,5 @@
   x
   x
   x
  -a
  +b
   
#else
  $ hg diff
  diff -r f0aeecb49805 a
  --- a/a	Thu Jan 01 00:00:00 1970 +0000
  +++ b/a	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,15 +1,4 @@
  -a
  -x
  -x
  -x
  -x
  -x
  -x
  -x
  -x
  -x
  -x
  -u
  +b
   x
   x
   x
  @@ -40,5 +29,16 @@
   x
   x
   x
  -a
  +u
  +x
  +x
  +x
  +x
  +x
  +x
  +x
  +x
  +x
  +x
  +b
   
#endif