>From the perspective of a newcomer to the codebase, the directory
traversal API has a few potentially confusing properties. These
comments clarify a few key aspects and will hopefully make it easier
to understand for other newcomers in the future.
Signed-off-by: Adam Spiers <git@xxxxxxxxxxxxxx>
---
For some reason this patch was dropped from the v2 series when it was
applied to the 'pu' branch.
Documentation/technical/api-directory-listing.txt | 9 +++++---
dir.c | 8 ++++++-
dir.h | 26 +++++++++++++++++++++--
3 files changed, 37 insertions(+), 6 deletions(-)
diff --git a/Documentation/technical/api-directory-listing.txt b/Documentation/technical/api-directory-listing.txt
index 0356d25..944fc39 100644
--- a/Documentation/technical/api-directory-listing.txt
+++ b/Documentation/technical/api-directory-listing.txt
@@ -9,8 +9,11 @@ Data structure
--------------
`struct dir_struct` structure is used to pass directory traversal
-options to the library and to record the paths discovered. The notable
-options are:
+options to the library and to record the paths discovered. A single
+`struct dir_struct` is used regardless of whether or not the traversal
+recursively descends into subdirectories.
+
+The notable options are:
`exclude_per_dir`::
@@ -39,7 +42,7 @@ options are:
If set, recurse into a directory that looks like a git
directory. Otherwise it is shown as a directory.
-The result of the enumeration is left in these fields::
+The result of the enumeration is left in these fields:
`entries[]`::
diff --git a/dir.c b/dir.c
index ee8e711..89e27a6 100644
--- a/dir.c
+++ b/dir.c
@@ -2,6 +2,8 @@
* This handles recursive filename detection with exclude
* files, index knowledge etc..
*
+ * See Documentation/technical/api-directory-listing.txt
+ *
* Copyright (C) Linus Torvalds, 2005-2006
* Junio Hamano, 2005-2006
*/
@@ -476,6 +478,10 @@ void add_excludes_from_file(struct dir_struct *dir, const char *fname)
die("cannot use %s as an exclude file", fname);
}
+/*
+ * Loads the per-directory exclude list for the substring of base
+ * which has a char length of baselen.
+ */
static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
{
struct exclude_list *el;
@@ -486,7 +492,7 @@ static void prep_exclude(struct dir_struct *dir, const char *base, int baselen)
(baselen + strlen(dir->exclude_per_dir) >= PATH_MAX))
return; /* too long a path -- ignore */
- /* Pop the ones that are not the prefix of the path being checked. */
+ /* Pop the directories that are not the prefix of the path being checked. */
el = &dir->exclude_list[EXC_DIRS];
while ((stk = dir->exclude_stack) != NULL) {
if (stk->baselen <= baselen &&
diff --git a/dir.h b/dir.h
index f5c89e3..e0869bc 100644
--- a/dir.h
+++ b/dir.h
@@ -1,6 +1,8 @@
#ifndef DIR_H
#define DIR_H
+/* See Documentation/technical/api-directory-listing.txt */
+
#include "strbuf.h"
struct dir_entry {
@@ -13,6 +15,12 @@ struct dir_entry {
#define EXC_FLAG_MUSTBEDIR 8
#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).
+ */
struct exclude_list {
int nr;
int alloc;
@@ -26,9 +34,15 @@ struct exclude_list {
} **excludes;
};
+/*
+ * The contents of the per-directory exclude files are lazily read on
+ * demand and then cached in memory, one per exclude_stack struct, in
+ * order to avoid opening and parsing each one every time that
+ * directory is traversed.
+ */
struct exclude_stack {
- struct exclude_stack *prev;
- char *filebuf;
+ 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;
};
@@ -59,6 +73,14 @@ struct dir_struct {
#define EXC_DIRS 1
#define EXC_FILE 2
+ /*
+ * Temporary variables which are used during loading of the
+ * per-directory exclude lists.
+ *
+ * exclude_stack points to the top of the exclude_stack, and
+ * basebuf contains the full path to the current
+ * (sub)directory in the traversal.
+ */
struct exclude_stack *exclude_stack;
char basebuf[PATH_MAX];
};
--
1.7.11.2.249.g31c7954
--
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