[PATCH v2 05/25] sequencer: allow the sequencer to take custody of malloc()ed data

[Johannes Schindelin]

The sequencer is our attempt to lib-ify cherry-pick. Yet it behaves
like a one-shot command when it reads its configuration: memory is
allocated and released only when the command exits.

This is kind of okay for git-cherry-pick, which *is* a one-shot
command. All the work to make the sequencer its work horse was
done to allow using the functionality as a library function, though,
including proper clean-up after use.

This patch introduces an API to pass the responsibility of releasing
certain memory to the sequencer. Example:

        const char *label =
                sequencer_entrust(opts, xstrfmt("From: %s", email));

The entrusted memory will remain valid until sequencer_remove_state() is
called, or the program exits, whichever comes first.

Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de>
---
 sequencer.c | 13 +++++++++++++
 sequencer.h | 10 ++++++++++
 2 files changed, 23 insertions(+)

diff --git a/sequencer.c b/sequencer.c
index 8d272fb..8d56a05 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -114,9 +114,22 @@ static int has_conforming_footer(struct strbuf *sb, struct 
strbuf *sob,
        return 1;
 }
 
+void *sequencer_entrust(struct replay_opts *opts, void *to_free)
+{
+       ALLOC_GROW(opts->owned, opts->owned_nr + 1, opts->owned_alloc);
+       opts->owned[opts->owned_nr++] = to_free;
+
+       return to_free;
+}
+
 static void remove_sequencer_state(const struct replay_opts *opts)
 {
        struct strbuf dir = STRBUF_INIT;
+       int i;
+
+       for (i = 0; i < opts->owned_nr; i++)
+               free(opts->owned[i]);
+       free(opts->owned);
 
        strbuf_addf(&dir, "%s", get_dir(opts));
        remove_dir_recursively(&dir, 0);
diff --git a/sequencer.h b/sequencer.h
index dd4d33a..04892a9 100644
--- a/sequencer.h
+++ b/sequencer.h
@@ -43,9 +43,19 @@ struct replay_opts {
 
        /* Only used by REPLAY_NONE */
        struct rev_info *revs;
+
+       /* malloc()ed data entrusted to the sequencer */
+       void **owned;
+       int owned_nr, owned_alloc;
 };
 #define REPLAY_OPTS_INIT { -1, -1 }
 
+/*
+ * Make it the duty of sequencer_remove_state() to release the memory;
+ * For ease of use, return the same pointer.
+ */
+void *sequencer_entrust(struct replay_opts *opts, void *to_free);
+
 int sequencer_pick_revisions(struct replay_opts *opts);
 
 extern const char sign_off_header[];
-- 
2.10.0.windows.1.10.g803177d