From 95a68344afcaf229765921c70458ee76add342dc Mon Sep 17 00:00:00 2001 From: Adam Spiers Date: Thu, 27 Dec 2012 02:32:21 +0000 Subject: [PATCH] Improve documentation and comments regarding directory traversal API 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 Signed-off-by: Junio C Hamano --- .../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 0356d2597..944fc39fa 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 ee8e7115a..89e27a682 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 f5c89e3b8..e0869bca2 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]; }; -- 2.26.2