From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Tan Subject: [PATCH/WIP v3 04/31] am: implement patch queue mechanism Date: Thu, 18 Jun 2015 19:25:16 +0800 Message-ID: <1434626743-8552-5-git-send-email-pyokagan@gmail.com> References: <1434626743-8552-1-git-send-email-pyokagan@gmail.com> Cc: Johannes Schindelin , Stefan Beller , Paul Tan To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Thu Jun 18 13:26:54 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 1Z5Xxx-0004e3-9J for gcvg-git-2@plane.gmane.org; Thu, 18 Jun 2015 13:26:41 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755500AbbFRL0g (ORCPT ); Thu, 18 Jun 2015 07:26:36 -0400 Received: from mail-pd0-f170.google.com ([209.85.192.170]:33639 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755280AbbFRL0X (ORCPT ); Thu, 18 Jun 2015 07:26:23 -0400 Received: by pdjn11 with SMTP id n11so64826324pdj.0 for ; Thu, 18 Jun 2015 04:26:22 -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=Ig0T91kIB9jkPQ09b4CvyF8JK8MBEJE0pabDV4GvJGc=; b=Pt6KJ3heDPkbLZAYXQdfYK2goeUEhqx7eVdE0SeB9MxX/erwdhiCGW+RB5xli2wwKb emZxxHudqauBClrDq4csOyoR4X72VhBs3JU3c8+IxNzcbShnjCFXCBkR8QEgDTSNUW/L hjEs8Ypxy4Vy6gs0/E7XOSoCtvruz5+9yuyRu9TXDRfAY8wvWI6e0KZaNGuBbW32un/5 HxPt6/z/RB9SHfNY7gpJz6Qsm3XDgnCCCWSbdCFA3Q8gAssAMhIpx44k3B2Ne67VPHKd 0u8y6IwWcOzRLx+InPAGF9u9WJvdqNUAI7/xflYf3LWJ982eGyDxc6l/bBChHW3boiLP 0z4A== X-Received: by 10.68.163.68 with SMTP id yg4mr20364573pbb.4.1434626782450; Thu, 18 Jun 2015 04:26:22 -0700 (PDT) Received: from yoshi.pyokagan.tan ([116.86.132.138]) by mx.google.com with ESMTPSA id j9sm5443016pdl.65.2015.06.18.04.26.19 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 18 Jun 2015 04:26:21 -0700 (PDT) X-Mailer: git-send-email 2.1.4 In-Reply-To: <1434626743-8552-1-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. Signed-off-by: Paul Tan --- builtin/am.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) diff --git a/builtin/am.c b/builtin/am.c index dbc8836..af68c51 100644 --- a/builtin/am.c +++ b/builtin/am.c @@ -6,6 +6,158 @@ #include "cache.h" #include "builtin.h" #include "exec_cmd.h" +#include "parse-options.h" +#include "dir.h" + +struct am_state { + /* state directory path */ + struct strbuf dir; + + /* current and last patch numbers, 1-indexed */ + int cur; + int last; +}; + +/** + * Initializes am_state with the default values. + */ +static void am_state_init(struct am_state *state) +{ + memset(state, 0, sizeof(*state)); + + strbuf_init(&state->dir, 0); +} + +/** + * Release memory allocated by an am_state. + */ +static void am_state_release(struct am_state *state) +{ + strbuf_release(&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.buf, 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.buf, &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`. The third argument can be used to give a hint + * about the file size, to avoid reallocs. Returns number of bytes read on + * success, -1 if the file does not exist. If trim is set, trailing whitespace + * will be removed from the file contents. + */ +static int read_state_file(struct strbuf *sb, const char *file, size_t hint, int trim) +{ + strbuf_reset(sb); + if (strbuf_read_file(sb, file, hint) >= 0) { + if (trim) + strbuf_trim(sb); + + return sb->len; + } + + if (errno == ENOENT) + return -1; + + die_errno(_("could not read '%s'"), file); +} + +/** + * Loads state from disk. + */ +static void am_load(struct am_state *state) +{ + struct strbuf sb = STRBUF_INIT; + + read_state_file(&sb, am_path(state, "next"), 8, 1); + state->cur = strtol(sb.buf, NULL, 10); + + read_state_file(&sb, am_path(state, "last"), 8, 1); + state->last = strtol(sb.buf, NULL, 10); + + strbuf_release(&sb); +} + +/** + * Remove the am_state directory. + */ +static void am_destroy(const struct am_state *state) +{ + struct strbuf sb = STRBUF_INIT; + + strbuf_addstr(&sb, state->dir.buf); + 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.buf, 0777) < 0 && errno != EEXIST) + die_errno(_("failed to create directory '%s'"), state->dir.buf); + + 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 patches. + */ +static void am_run(struct am_state *state) +{ + while (state->cur <= state->last) { + + /* TODO: Patch application not implemented yet */ + + am_next(state); + } + + am_destroy(state); +} + +static struct am_state state; + +static const char * const am_usage[] = { + N_("git am [options] [(|)...]"), + NULL +}; + +static struct option am_options[] = { + OPT_END() +}; int cmd_am(int argc, const char **argv, const char *prefix) { @@ -24,5 +176,21 @@ int cmd_am(int argc, const char **argv, const char *prefix) setup_work_tree(); } + git_config(git_default_config, NULL); + + am_state_init(&state); + strbuf_addstr(&state.dir, git_path("rebase-apply")); + + argc = parse_options(argc, argv, prefix, am_options, am_usage, 0); + + if (am_in_progress(&state)) + am_load(&state); + else + am_setup(&state); + + am_run(&state); + + am_state_release(&state); + return 0; } -- 2.1.4