Re: [PATCH v4 40/44] builtin-am: support and auto-detect mercurial patches

[Stefan Beller <sbeller@google.com>]

On Sun, Jun 28, 2015 at 7:06 AM, Paul Tan <pyokagan@gmail.com> wrote:
> Since 0cfd112 (am: preliminary support for hg patches, 2011-08-29),
> git-am.sh could convert mercurial patches to an RFC2822 mail patch
> suitable for parsing with git-mailinfo, and queue them in the state
> directory for application.
>
> Since 15ced75 (git-am foreign patch support: autodetect some patch
> formats, 2009-05-27), git-am.sh was able to auto-detect mercurial
> patches by checking if the file begins with the line:
>
>         # HG changeset patch
>
> Re-implement the above in builtin/am.c.
>
> Signed-off-by: Paul Tan <pyokagan@gmail.com>
> ---
>  builtin/am.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/builtin/am.c b/builtin/am.c
> index 1576bd4..5c86e6f 100644
> --- a/builtin/am.c
> +++ b/builtin/am.c
> @@ -81,7 +81,8 @@ enum patch_format {
>         PATCH_FORMAT_UNKNOWN = 0,
>         PATCH_FORMAT_MBOX,
>         PATCH_FORMAT_STGIT,
> -       PATCH_FORMAT_STGIT_SERIES
> +       PATCH_FORMAT_STGIT_SERIES,
> +       PATCH_FORMAT_HG
>  };
>
>  enum keep_type {
> @@ -697,6 +698,11 @@ static int detect_patch_format(const char **paths)
>                 goto done;
>         }
>
> +       if (!strcmp(l1.buf, "# HG changeset patch")) {
> +               ret = PATCH_FORMAT_HG;
> +               goto done;
> +       }
> +
>         strbuf_reset(&l2);
>         strbuf_getline_crlf(&l2, fp);
>         strbuf_reset(&l3);
> @@ -895,6 +901,67 @@ static int split_mail_stgit_series(struct am_state *state, const char **paths,
>  }
>
>  /**
> + * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
> + * message suitable for parsing with git-mailinfo.
> + */
> +static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
> +{
> +       struct strbuf sb = STRBUF_INIT;
> +
> +       while (!strbuf_getline(&sb, in, '\n')) {
> +               const char *str;
> +
> +               if (skip_prefix(sb.buf, "# User ", &str))
> +                       fprintf(out, "From: %s\n", str);
> +               else if (skip_prefix(sb.buf, "# Date ", &str)) {
> +                       unsigned long timestamp;
> +                       long tz;
> +                       char *end;
> +
> +                       errno = 0;
> +                       timestamp = strtoul(str, &end, 10);
> +                       if (errno)
> +                               return error(_("invalid timestamp"));
> +
> +                       if (!skip_prefix(end, " ", &str))
> +                               return error(_("invalid Date line"));
> +
> +                       errno = 0;
> +                       tz = strtol(str, &end, 10);
> +                       if (errno)
> +                               return error(_("invalid timezone offset"));
> +
> +                       if (*end)
> +                               return error(_("invalid Date line"));
> +
> +                       /*
> +                        * mercurial's timezone is in seconds west of UTC,
> +                        * however git's timezone is in hours + minutes east of
> +                        * UTC. Convert it.
> +                        */
> +                       tz = tz / (60 * 60) * 100 + tz % (60 * 60);

What happens if we have a negative input not matching a full hour, say -5400 ?
(would equate to 0130 in git)

for calculating the minutes we would only need to take % 3600 (which
you do), but
then we still need to divide by 60 to convert seconds to minutes?

> +                       tz = -tz;
> +
> +                       fprintf(out, "Date: %s\n", show_date(timestamp, tz, DATE_RFC2822));
> +               } else if (starts_with(sb.buf, "# ")) {
> +                       continue;
> +               } else {
> +                       fprintf(out, "\n%s\n", sb.buf);
> +                       break;
> +               }
> +       }
> +
> +       strbuf_reset(&sb);
> +       while (strbuf_fread(&sb, 8192, in) > 0) {
> +               fwrite(sb.buf, 1, sb.len, out);
> +               strbuf_reset(&sb);
> +       }
> +
> +       strbuf_release(&sb);
> +       return 0;
> +}
> +
> +/**
>   * Splits a list of files/directories into individual email patches. Each path
>   * in `paths` must be a file/directory that is formatted according to
>   * `patch_format`.
> @@ -926,6 +993,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
>                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
>         case PATCH_FORMAT_STGIT_SERIES:
>                 return split_mail_stgit_series(state, paths, keep_cr);
> +       case PATCH_FORMAT_HG:
> +               return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
>         default:
>                 die("BUG: invalid patch_format");
>         }
> @@ -1960,6 +2029,8 @@ static int parse_opt_patchformat(const struct option *opt, const char *arg, int
>                 *opt_value = PATCH_FORMAT_STGIT;
>         else if (!strcmp(arg, "stgit-series"))
>                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
> +       else if (!strcmp(arg, "hg"))
> +               *opt_value = PATCH_FORMAT_HG;
>         else
>                 return error(_("Invalid value for --patch-format: %s"), arg);
>         return 0;
> --
> 2.5.0.rc0.76.gb2c6e93
>