From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Beller Subject: Re: [PATCH/WIP v2 04/19] am: implement patch queue mechanism Date: Thu, 11 Jun 2015 10:39:50 -0700 Message-ID: References: <1434018125-31804-1-git-send-email-pyokagan@gmail.com> <1434018125-31804-5-git-send-email-pyokagan@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: "git@vger.kernel.org" , Johannes Schindelin To: Paul Tan X-From: git-owner@vger.kernel.org Thu Jun 11 19:40:04 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 1Z36SS-0001Fk-09 for gcvg-git-2@plane.gmane.org; Thu, 11 Jun 2015 19:40:04 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755099AbbFKRjy (ORCPT ); Thu, 11 Jun 2015 13:39:54 -0400 Received: from mail-yk0-f169.google.com ([209.85.160.169]:32889 "EHLO mail-yk0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755090AbbFKRjv (ORCPT ); Thu, 11 Jun 2015 13:39:51 -0400 Received: by ykfr66 with SMTP id r66so6002741ykf.0 for ; Thu, 11 Jun 2015 10:39:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=T0L6lV3ab4XhkozqO7eAL0xc+T5dUTikaPhEXpLzJyU=; b=OCrMAnc9qlUJJY1qlwjQonN6/qqCO6seJFfqtmvIhCO3ymgNPmnyEB63Jvc12y4gl9 Vd/cCkEovRfBrxU+IxuPiSEHaYRtwoophy/cPhVYNzbe0X8NcDqmAmQaPhfZ+9nmZBFy BRYqWQ3brlzsd9f9aFIxuF/HmXpvnBUAQvSxqB/XAOYY8Y2LvPSS/gDECKxQDNICIeRX eNn8Lam960mhm7Nc8UWHuO2jFxr/BT9RaFKgDhOv0ZwlSY2tdnEbVgNqXp7WuAYaLiRG YAw75XoHzDE64r3ZKg0G42WvDB+AsrvcxYyNnLa8tLVEdYX3RR3G9jlZ+CVdOhzMiV7G 3dvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=T0L6lV3ab4XhkozqO7eAL0xc+T5dUTikaPhEXpLzJyU=; b=BzD08oK0oRPr98YiwZpDz/H7UYqYRMxZZ/FopT2PQP1ZUsvHNi3FMYlc9tPQMLm11R eiH7VHsH0uEbkg4iBuUwJbchRn9eHElhe3RsCliMD3MnXaL25jfcstDBQt1UKDTr9Woq GBD6dw7kUGNms1W/oIPorAhm4mxCRxsd3I6d4zolTR4xv4FWytcXF9kq4z5aCPlh8f8z p140wquF5A12GkwPg3lLMnGJCYdK7mwtJs5r5jqOlE0ldSlgL3wzXDOgX/ZYLcaKV6g2 WLK1yGKQaXTR3pICjfq2fZTTOxz6S5RKu77BEbtv1lluGZQyEWVP82KyrODpikfRzlT4 m+UA== X-Gm-Message-State: ALoCoQnco2WrgxLYGVoOZNLY3CkG4S4/GuMpnvM9HHihI3CTl7sgj0hbF7Y6ZkAN9jmoBydNnTMH X-Received: by 10.170.41.76 with SMTP id 73mr1373994ykj.101.1434044390852; Thu, 11 Jun 2015 10:39:50 -0700 (PDT) Received: by 10.37.101.197 with HTTP; Thu, 11 Jun 2015 10:39:50 -0700 (PDT) In-Reply-To: <1434018125-31804-5-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: On Thu, Jun 11, 2015 at 3:21 AM, Paul Tan wrote: > 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 > --- > > Notes: > v2 > > * Declare struct am_state as static > > builtin/am.c | 164 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 164 insertions(+) > > diff --git a/builtin/am.c b/builtin/am.c > index 0ccbe33..f061d21 100644 > --- a/builtin/am.c > +++ b/builtin/am.c > @@ -6,6 +6,154 @@ > #include "cache.h" > #include "builtin.h" > #include "exec_cmd.h" > +#include "parse-options.h" > +#include "dir.h" > + > +struct am_state { Did you mean to declare all the functions below to be static or the struct as well? Reading further, you declared it static below. I thought maybe it'd be useful to have definition and declaration up here, but having all declarations further below may be even better. > + /* 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_rtrim(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) > + 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) > { > @@ -16,5 +164,21 @@ int cmd_am(int argc, const char **argv, const char *prefix) > die_errno("could not exec %s", path); > } > > + 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 >