Hi Stefan,
On Tue, Mar 15, 2016 at 4:30 AM, Stefan Beller <sbel...@google.com> wrote:
> On Sat, Mar 12, 2016 at 2:46 AM, Paul Tan <pyoka...@gmail.com> wrote:
>> These functions can be used for loading and saving common rebase options
>> into a state directory.
>>
>> Signed-off-by: Paul Tan <pyoka...@gmail.com>
>> ---
>> rebase-common.c | 69
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> rebase-common.h | 4 ++++
>> 2 files changed, 73 insertions(+)
>>
>> diff --git a/rebase-common.c b/rebase-common.c
>> index 5a49ac4..1835f08 100644
>> --- a/rebase-common.c
>> +++ b/rebase-common.c
>> @@ -26,3 +26,72 @@ void rebase_options_swap(struct rebase_options *dst,
>> struct rebase_options *src)
>> *dst = *src;
>> *src = tmp;
>> }
>> +
>> +static int state_file_exists(const char *dir, const char *file)
>> +{
>> + return file_exists(mkpath("%s/%s", dir, file));
>> +}
>
> How is this specific to the state file? All it does is create the
> leading directory
> if it doesn't exist? (So I'd expect file_exists(concat(dir, file)) to
> have the same
> result without actually creating the directory if it doesn't exist as
> a side effect?
I don't quite understand, AFAIK mkpath() does not create any
directories as a side-effect. And yes, I just wanted a short way to
say file_exists(concat(dir, file)) or file_exists(mkpath("%s/%s", dir,
file)) without cluttering up the code.
> If the dir doesn't exist it can be created in rebase_options_load explicitly?
I don't intend to create any directories if they do not exist.
>> +
>> +static int read_state_file(struct strbuf *sb, const char *dir, const char
>> *file)
>> +{
>> + const char *path = mkpath("%s/%s", dir, file);
>> + strbuf_reset(sb);
>> + if (strbuf_read_file(sb, path, 0) >= 0)
>> + return sb->len;
>> + else
>> + return error(_("could not read '%s'"), path);
>> +}
>> +
>> +int rebase_options_load(struct rebase_options *opts, const char *dir)
>> +{
>> + struct strbuf sb = STRBUF_INIT;
>> + const char *filename;
>> +
>> + /* opts->orig_refname */
>> + if (read_state_file(&sb, dir, "head-name") < 0)
>> + return -1;
>> + strbuf_trim(&sb);
>> + if (starts_with(sb.buf, "refs/heads/"))
>> + opts->orig_refname = strbuf_detach(&sb, NULL);
>> + else if (!strcmp(sb.buf, "detached HEAD"))
>> + opts->orig_refname = NULL;
>> + else
>> + return error(_("could not parse %s"), mkpath("%s/%s", dir,
>> "head-name"));
>> +
>> + /* opts->onto */
>> + if (read_state_file(&sb, dir, "onto") < 0)
>> + return -1;
>> + strbuf_trim(&sb);
>> + if (get_oid_hex(sb.buf, &opts->onto) < 0)
>> + return error(_("could not parse %s"), mkpath("%s/%s", dir,
>> "onto"));
>> +
>> + /*
>> + * We always write to orig-head, but interactive rebase used to write
>> + * to head. Fall back to reading from head to cover for the case that
>> + * the user upgraded git with an ongoing interactive rebase.
>> + */
>> + filename = state_file_exists(dir, "orig-head") ? "orig-head" :
>> "head";
>> + if (read_state_file(&sb, dir, filename) < 0)
>> + return -1;
>
> So from here on we always use "orig-head" instead of "head" for
> interactive rebase.
> Would people ever rely on the (internal) file name and have e.g.
> scripts which operate
> on the "head" file ?
This backwards-compatibility code is just a straight port from the
code in git-rebase.sh.
The usage of orig-head has been around since 2011 with 84df456
(rebase: extract code for writing basic state, 2011-02-06), so I guess
if people had issues with it, it would have been reported.
>
>
>> + strbuf_trim(&sb);
>> + if (get_oid_hex(sb.buf, &opts->orig_head) < 0)
>> + return error(_("could not parse %s"), mkpath("%s/%s", dir,
>> filename));
>> +
>> + strbuf_release(&sb);
>> + return 0;
>> +}
>> +
>> +static int write_state_text(const char *dir, const char *file, const char
>> *string)
>> +{
>> + return write_file(mkpath("%s/%s", dir, file), "%s", string);
>> +}
>
> Same comment as on checking the state files existence. I'm not sure if the
> side
> effect of creating the dir is better done explicitly where it is used.
> The concat of dir and
> file name can still be done in the helper though? (If the helper is
> needed at all then)
Same as above -- AFAIK I don't think mkpath() creates any directories
as a side-effect.
>
>> +
>> +void rebase_options_save(const struct rebase_options *opts, const char *dir)
>> +{
>> + const char *head_name = opts->orig_refname;
>> + if (!head_name)
>> + head_name = "detached HEAD";
>> + write_state_text(dir, "head-name", head_name);
>> + write_state_text(dir, "onto", oid_to_hex(&opts->onto));
>> + write_state_text(dir, "orig-head", oid_to_hex(&opts->orig_head));
>> +}
>> diff --git a/rebase-common.h b/rebase-common.h
>> index db5146a..051c056 100644
>> --- a/rebase-common.h
>> +++ b/rebase-common.h
>> @@ -20,4 +20,8 @@ void rebase_options_release(struct rebase_options *);
>>
>> void rebase_options_swap(struct rebase_options *dst, struct rebase_options
>> *src);
>>
>> +int rebase_options_load(struct rebase_options *, const char *dir);
>> +
>> +void rebase_options_save(const struct rebase_options *, const char *dir);
>> +
>> #endif /* REBASE_COMMON_H */
>> --
>> 2.7.0
Thanks,
Paul
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