Re: [PATCH/WIP v3 04/31] am: implement patch queue mechanism

[Stefan Beller <sbeller@google.com>]

On Thu, Jun 18, 2015 at 4:25 AM, Paul Tan <pyokagan@gmail.com> wrote:
> +/**
> + * Reads the contents of `file`. The third argument can be used to give a hint

I would avoid `third` here. (I needed to count twice to be sure which
argument you
were referring to, as I was confused.) Also how do you abstain from
giving a hint?
(0 or negative or MAX_INT?)

So maybe

    /**
     * Reads the contents of `file`. 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. If `hint` is non-zero, it is used as a
hint for initial
     * allocation to avoid reallocs.
     */

> + * 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] [(<mbox>|<Maildir>)...]"),
> +       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
>