From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adam Spiers Subject: [PATCH v3 02/19] Improve documentation and comments regarding directory traversal API Date: Thu, 27 Dec 2012 02:32:21 +0000 Message-ID: <1356575558-2674-3-git-send-email-git@adamspiers.org> References: <1356575558-2674-1-git-send-email-git@adamspiers.org> To: git list X-From: git-owner@vger.kernel.org Thu Dec 27 03:33:04 2012 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1To3HK-0006HI-Jh for gcvg-git-2@plane.gmane.org; Thu, 27 Dec 2012 03:33:02 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752331Ab2L0Cco (ORCPT ); Wed, 26 Dec 2012 21:32:44 -0500 Received: from coral.adamspiers.org ([85.119.82.20]:53762 "EHLO coral.adamspiers.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751865Ab2L0Ccl (ORCPT ); Wed, 26 Dec 2012 21:32:41 -0500 Received: from localhost (host-2-103-56-128.as13285.net [2.103.56.128]) by coral.adamspiers.org (Postfix) with ESMTPSA id 787EA2E5E6 for ; Thu, 27 Dec 2012 02:32:40 +0000 (GMT) X-Mailer: git-send-email 1.7.11.2.249.g31c7954 In-Reply-To: <1356575558-2674-1-git-send-email-git@adamspiers.org> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: >>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 --- 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