Reduce duplicated code between convert.c and attr.c.

* lf/read-blob-data-from-index:
  convert.c: remove duplicate code
  read_blob_data_from_index(): optionally return the size of blob data
  attr.c: extract read_index_data() as read_blob_data_from_index()

This allows for optionally getting the size of the returned data and
will be used in a follow-up patch.

Signed-off-by: Lukas Fleischer <git@cryptocrack.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Extract the read_index_data() function from attr.c and move it to
read-cache.c; rename it to read_blob_data_from_index() and update
the function signature of it to align better with index/cache API
functions.

This allows for reusing the function in convert.c later.

Signed-off-by: Lukas Fleischer <git@cryptocrack.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

A pattern "dir" (without trailing slash) in the attributes file
stopped matching a directory "dir" by mistake with an earlier change
that wanted to allow pattern "dir/" to also match.

* jc/directory-attrs-regression-fix:
  t: check that a pattern without trailing slash matches a directory
  dir.c::match_pathname(): pay attention to the length of string parameters
  dir.c::match_pathname(): adjust patternlen when shifting pattern
  dir.c::match_basename(): pay attention to the length of string parameters
  attr.c::path_matches(): special case paths that end with a slash
  attr.c::path_matches(): the basename is part of the pathname

Fix 1.8.1.x regression that stopped matching "dir" (without
trailing slash) to a directory "dir".

* jc/directory-attrs-regression-fix:
  t: check that a pattern without trailing slash matches a directory
  dir.c::match_pathname(): pay attention to the length of string parameters
  dir.c::match_pathname(): adjust patternlen when shifting pattern
  dir.c::match_basename(): pay attention to the length of string parameters
  attr.c::path_matches(): special case paths that end with a slash
  attr.c::path_matches(): the basename is part of the pathname

The function is given a string that ends with a slash to signal that
the path is a directory to make sure that a pattern that ends with a
slash (i.e. MUSTBEDIR) can tell directories and non-directories
apart.  However, the pattern itself (pat->pattern and
pat->patternlen) that came from such a MUSTBEDIR pattern is
represented as a string that ends with a slash, but patternlen does
not count that trailing slash. A MUSTBEDIR pattern "element/" is
represented as a counted string <"element/", 7> and this must match
match pathname "element/".

Because match_basename() and match_pathname() want to see pathname
"element" to match against the pattern <"element/", 7>, reduce the
length of the path to exclude the trailing slash when calling
these functions.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The function takes two strings (pathname and basename) as if they
are independent strings, but in reality, the latter is always
pointing into a substring in the former.

Clarify this relationship by expressing the latter as an offset into
the former.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Before 82dce99 (attr: more matching optimizations from .gitignore,
2012-10-15), .gitattributes did not have any special treatment of a
leading '!'.  The docs, however, always said

  The rules how the pattern matches paths are the same as in
  `.gitignore` files; see linkgit:gitignore[5].

By those rules, leading '!' means pattern negation.  So 82dce99
correctly determined that this kind of line makes no sense and should
be disallowed.

However, users who actually had a rule for files starting with a '!'
are in a bad position: before 82dce99 '!' matched that literal
character, so it is conceivable that users have .gitattributes with
such lines in them.  After 82dce99 the unescaped version was
disallowed in such a way that git outright refuses to run(!) most
commands in the presence of such a .gitattributes.  It therefore
becomes very hard to fix, let alone work with, such repositories.

Let's at least allow the users to fix their repos: change the fatal
error into a warning.

Reported-by: mathstuf@gmail.com
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

The attribute mechanism didn't allow limiting attributes to be
applied to only a single directory itself with "path/" like the
exclude mechanism does.  The initial implementation of this that was
merged to 'maint' and 1.8.1.1 had severe performance degradations.

* nd/fix-directory-attrs-off-by-one:
  attr: avoid calling find_basename() twice per path
  attr: fix off-by-one directory component length calculation