dir.c: use a single struct exclude_list per source of excludes

Previously each exclude_list could potentially contain patterns
from multiple sources.  For example dir->exclude_list[EXC_FILE]
would typically contain patterns from .git/info/exclude and
core.excludesfile, and dir->exclude_list[EXC_DIRS] could contain
patterns from multiple per-directory .gitignore files during
directory traversal (i.e. when dir->exclude_stack was more than
one item deep).

We split these composite exclude_lists up into three groups of
exclude_lists (EXC_CMDL / EXC_DIRS / EXC_FILE as before), so that each
exclude_list now contains patterns from a single source.  This will
allow us to cleanly track the origin of each pattern simply by adding
a src field to struct exclude_list, rather than to struct exclude,
which would make memory management of the source string tricky in the
EXC_DIRS case where its contents are dynamically generated.

Similarly, by moving the filebuf member from struct exclude_stack to
struct exclude_list, it allows us to track and subsequently free
memory buffers allocated during the parsing of all exclude files,
rather than only tracking buffers allocated for files in the EXC_DIRS
group.

Signed-off-by: Adam Spiers <git@adamspiers.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt
index 944fc39fac..fa9c8ae461 100644
--- a/Documentation/technical/api-directory-listing.txt
+++ b/Documentation/technical/api-directory-listing.txt
@@ -67,11 +67,13 @@ marked. If you to exclude files, make sure you have loaded index first.
 * Prepare `struct dir_struct dir` and clear it with `memset(&dir, 0,
   sizeof(dir))`.
 
-* Call `add_exclude()` to add single exclude pattern,
-  `add_excludes_from_file()` to add patterns from a file
-  (e.g. `.git/info/exclude`), and/or set `dir.exclude_per_dir`.  A
-  short-hand function `setup_standard_excludes()` can be used to set up
-  the standard set of exclude settings.
+* To add single exclude pattern, call `add_exclude_list()` and then
+  `add_exclude()`.
+
+* To add patterns from a file (e.g. `.git/info/exclude`), call
+  `add_excludes_from_file()` , and/or set `dir.exclude_per_dir`.  A
+  short-hand function `setup_standard_excludes()` can be used to set
+  up the standard set of exclude settings.
 
 * Set options described in the Data Structure section above.