From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Tan Subject: [PATCH v7 04/45] builtin-am: implement patch queue mechanism Date: Tue, 4 Aug 2015 21:51:25 +0800 Message-ID: <1438696326-19590-5-git-send-email-pyokagan@gmail.com> References: <1438696326-19590-1-git-send-email-pyokagan@gmail.com> Cc: Stefan Beller , Johannes Schindelin , Paul Tan To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Tue Aug 04 15:59:21 2015 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 1ZMckS-0005BG-FO for gcvg-git-2@plane.gmane.org; Tue, 04 Aug 2015 15:59:20 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934302AbbHDN7P (ORCPT ); Tue, 4 Aug 2015 09:59:15 -0400 Received: from mail-pa0-f53.google.com ([209.85.220.53]:35324 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934170AbbHDNxK (ORCPT ); Tue, 4 Aug 2015 09:53:10 -0400 Received: by pasy3 with SMTP id y3so9185523pas.2 for ; Tue, 04 Aug 2015 06:53:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=qTW3DRv8d2v2bh9NJIGoLF72z5TKMggSlUbUrxs5EyY=; b=cGCrSZ3YHV1GfXwQhkLIgocAhv8CoBKV/P7IYqDjnc5rM+YCCtiFIyX1hNnTKv1Z1D 6RC97+/bbqMBJ9kIsFGIv5XA8DiElsGz5qL6A9923o3a7eN26OL6jNtxwst1UhPHyAIC AA2ho2abTsc5SdSK305C0eA4SKrNY+S+gVBpn0DUJ0y8klqOODWgQLx9zqnjepWbgXTH f/SRvq1imOQlXFh9tm2+4K+Bqp450fO3H0w/5tz5yLtDEdVicbRgK8B1qS5BqdSVx53r kknlZe2nsDGjVFHL1vI3DyZA6P8vk1TJdFaa0GAAqIh4uKNmsRuXgZhRD+z5O6bHRuZe uhPg== X-Received: by 10.68.166.196 with SMTP id zi4mr7938443pbb.83.1438696388662; Tue, 04 Aug 2015 06:53:08 -0700 (PDT) Received: from yoshi.pyokagan.tan ([116.86.132.138]) by smtp.gmail.com with ESMTPSA id ph4sm1580517pdb.43.2015.08.04.06.53.06 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 04 Aug 2015 06:53:07 -0700 (PDT) X-Mailer: git-send-email 2.5.0.280.gd88bd6e In-Reply-To: <1438696326-19590-1-git-send-email-pyokagan@gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: git-am applies a series of patches. If the process terminates abnormally, we want to be able to resume applying the series of patches. This requires the session state to be saved in a persistent location. Implement the mechanism of a "patch queue", represented by 2 integers -- the index of the current patch we are applying and the index of the last patch, as well as its lifecycle through the following functions: * am_setup(), which will set up the state directory $GIT_DIR/rebase-apply. As such, even if the process exits abnormally, the last-known state will still persist. * am_load(), which is called if there is an am session in progress, to load the last known state from the state directory so we can resume applying patches. * am_run(), which will do the actual patch application. After applying a patch, it calls am_next() to increment the current patch index. The logic for applying and committing a patch is not implemented yet. * am_destroy(), which is finally called when we successfully applied all the patches in the queue, to clean up by removing the state directory and its contents. Helped-by: Junio C Hamano Helped-by: Stefan Beller Helped-by: Johannes Schindelin Signed-off-by: Paul Tan --- builtin/am.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 177 insertions(+) diff --git a/builtin/am.c b/builtin/am.c index fd32caf..ac172c4 100644 --- a/builtin/am.c +++ b/builtin/am.c @@ -6,9 +6,171 @@ #include "cache.h" #include "builtin.h" #include "exec_cmd.h" +#include "parse-options.h" +#include "dir.h" + +struct am_state { + /* state directory path */ + char *dir; + + /* current and last patch numbers, 1-indexed */ + int cur; + int last; +}; + +/** + * Initializes am_state with the default values. The state directory is set to + * dir. + */ +static void am_state_init(struct am_state *state, const char *dir) +{ + memset(state, 0, sizeof(*state)); + + assert(dir); + state->dir = xstrdup(dir); +} + +/** + * Releases memory allocated by an am_state. + */ +static void am_state_release(struct am_state *state) +{ + free(state->dir); +} + +/** + * Returns path relative to the am_state directory. + */ +static inline const char *am_path(const struct am_state *state, const char *path) +{ + return mkpath("%s/%s", state->dir, path); +} + +/** + * Returns 1 if there is an am session in progress, 0 otherwise. + */ +static int am_in_progress(const struct am_state *state) +{ + struct stat st; + + if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode)) + return 0; + if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode)) + return 0; + if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode)) + return 0; + return 1; +} + +/** + * Reads the contents of `file` in the `state` directory into `sb`. Returns the + * number of bytes read on success, -1 if the file does not exist. If `trim` is + * set, trailing whitespace will be removed. + */ +static int read_state_file(struct strbuf *sb, const struct am_state *state, + const char *file, int trim) +{ + strbuf_reset(sb); + + if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) { + if (trim) + strbuf_trim(sb); + + return sb->len; + } + + if (errno == ENOENT) + return -1; + + die_errno(_("could not read '%s'"), am_path(state, file)); +} + +/** + * Loads state from disk. + */ +static void am_load(struct am_state *state) +{ + struct strbuf sb = STRBUF_INIT; + + if (read_state_file(&sb, state, "next", 1) < 0) + die("BUG: state file 'next' does not exist"); + state->cur = strtol(sb.buf, NULL, 10); + + if (read_state_file(&sb, state, "last", 1) < 0) + die("BUG: state file 'last' does not exist"); + state->last = strtol(sb.buf, NULL, 10); + + strbuf_release(&sb); +} + +/** + * Removes the am_state directory, forcefully terminating the current am + * session. + */ +static void am_destroy(const struct am_state *state) +{ + struct strbuf sb = STRBUF_INIT; + + strbuf_addstr(&sb, state->dir); + remove_dir_recursively(&sb, 0); + strbuf_release(&sb); +} + +/** + * Setup a new am session for applying patches + */ +static void am_setup(struct am_state *state) +{ + if (mkdir(state->dir, 0777) < 0 && errno != EEXIST) + die_errno(_("failed to create directory '%s'"), state->dir); + + /* + * NOTE: Since the "next" and "last" files determine if an am_state + * session is in progress, they should be written last. + */ + + write_file(am_path(state, "next"), 1, "%d", state->cur); + + write_file(am_path(state, "last"), 1, "%d", state->last); +} + +/** + * Increments the patch pointer, and cleans am_state for the application of the + * next patch. + */ +static void am_next(struct am_state *state) +{ + state->cur++; + write_file(am_path(state, "next"), 1, "%d", state->cur); +} + +/** + * Applies all queued mail. + */ +static void am_run(struct am_state *state) +{ + while (state->cur <= state->last) { + + /* NEEDSWORK: Patch application not implemented yet */ + + am_next(state); + } + + am_destroy(state); +} int cmd_am(int argc, const char **argv, const char *prefix) { + struct am_state state; + + const char * const usage[] = { + N_("git am [options] [(|)...]"), + NULL + }; + + struct option options[] = { + OPT_END() + }; /* * NEEDSWORK: Once all the features of git-am.sh have been @@ -25,5 +187,20 @@ int cmd_am(int argc, const char **argv, const char *prefix) setup_work_tree(); } + git_config(git_default_config, NULL); + + am_state_init(&state, git_path("rebase-apply")); + + argc = parse_options(argc, argv, prefix, options, usage, 0); + + if (am_in_progress(&state)) + am_load(&state); + else + am_setup(&state); + + am_run(&state); + + am_state_release(&state); + return 0; } -- 2.5.0.280.gd88bd6e