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, 26 insertions, 10 deletions

diff --git a/dir.h b/dir.h
index 5664ba8c64..c4d88dbc58 100644
--- a/dir.h
+++ b/dir.h
@@ -16,14 +16,18 @@ struct dir_entry {
 #define EXC_FLAG_NEGATIVE 16
 
 /*
- * Each .gitignore file will be parsed into patterns which are then
- * appended to the relevant exclude_list (either EXC_DIRS or
- * EXC_FILE).  exclude_lists are also used to represent the list of
- * --exclude values passed via CLI args (EXC_CMDL).
+ * Each excludes file will be parsed into a fresh exclude_list which
+ * is appended to the relevant exclude_list_group (either EXC_DIRS or
+ * EXC_FILE).  An exclude_list within the EXC_CMDL exclude_list_group
+ * can also be used to represent the list of --exclude values passed
+ * via CLI args.
  */
 struct exclude_list {
 	int nr;
 	int alloc;
+	/* remember pointer to exclude file contents so we can free() */
+	char *filebuf;
+
 	struct exclude {
 		const char *pattern;
 		int patternlen;
@@ -42,9 +46,13 @@ struct exclude_list {
  */
 struct exclude_stack {
 	struct exclude_stack *prev; /* the struct exclude_stack for the parent directory */
-	char *filebuf; /* remember pointer to per-directory exclude file contents so we can free() */
 	int baselen;
-	int exclude_ix;
+	int exclude_ix; /* index of exclude_list within EXC_DIRS exclude_list_group */
+};
+
+struct exclude_list_group {
+	int nr, alloc;
+	struct exclude_list *el;
 };
 
 struct dir_struct {
@@ -62,16 +70,23 @@ struct dir_struct {
 
 	/* Exclude info */
 	const char *exclude_per_dir;
-	struct exclude_list exclude_list[3];
+
 	/*
-	 * We maintain three exclude pattern lists:
+	 * We maintain three groups of exclude pattern lists:
+	 *
 	 * EXC_CMDL lists patterns explicitly given on the command line.
 	 * EXC_DIRS lists patterns obtained from per-directory ignore files.
-	 * EXC_FILE lists patterns from fallback ignore files.
+	 * EXC_FILE lists patterns from fallback ignore files, e.g.
+	 *   - .git/info/exclude
+	 *   - core.excludesfile
+	 *
+	 * Each group contains multiple exclude lists, a single list
+	 * per source.
 	 */
 #define EXC_CMDL 0
 #define EXC_DIRS 1
 #define EXC_FILE 2
+	struct exclude_list_group exclude_list_group[3];
 
 	/*
 	 * Temporary variables which are used during loading of the
@@ -129,8 +144,9 @@ extern struct exclude *last_exclude_matching_path(struct path_exclude_check *, c
 extern int is_path_excluded(struct path_exclude_check *, const char *, int namelen, int *dtype);
 
 
+extern struct exclude_list *add_exclude_list(struct dir_struct *dir, int group_type);
 extern int add_excludes_from_file_to_list(const char *fname, const char *base, int baselen,
-					  char **buf_p, struct exclude_list *el, int check_index);
+					  struct exclude_list *el, int check_index);
 extern void add_excludes_from_file(struct dir_struct *, const char *fname);
 extern void parse_exclude_pattern(const char **string, int *patternlen, int *flags, int *nowildcardlen);
 extern void add_exclude(const char *string, const char *base,