worktree: libify should_prune_worktree()

As part of teaching "git worktree list" to annotate worktree that is a
candidate for pruning, let's move should_prune_worktree() from
builtin/worktree.c to worktree.c in order to make part of the worktree
public API.

should_prune_worktree() knows how to select the given worktree for
pruning based on an expiration date, however the expiration value is
stored in a static file-scope variable and it is not local to the
function. In order to move the function, teach should_prune_worktree()
to take the expiration date as an argument and document the new
parameter that is not immediately obvious.

Also, change the function comment to clearly state that the worktree's
path is returned in `wtpath` argument.

Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Rafael Silva <rafaeloliveira.cs@gmail.com>
Reviewed-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/worktree.h b/worktree.h
index f38e6fd5a2..818e1491c7 100644
--- a/worktree.h
+++ b/worktree.h
@@ -73,6 +73,20 @@ int is_main_worktree(const struct worktree *wt);
  */
 const char *worktree_lock_reason(struct worktree *wt);
 
+/*
+ * Return true if worktree entry should be pruned, along with the reason for
+ * pruning. Otherwise, return false and the worktree's path in `wtpath`, or
+ * NULL if it cannot be determined. Caller is responsible for freeing
+ * returned path.
+ *
+ * `expire` defines a grace period to prune the worktree when its path
+ * does not exist.
+ */
+int should_prune_worktree(const char *id,
+			  struct strbuf *reason,
+			  char **wtpath,
+			  timestamp_t expire);
+
 #define WT_VALIDATE_WORKTREE_MISSING_OK (1 << 0)
 
 /*