[PATCH 8/8] checkout: move post_checkout_hook() to checkout.c

[Junio C Hamano <gitster@pobox.com>]

post_checkout_hook() in builtin/checkout.c runs the 'post-checkout' hook
after switching branches or checking out paths.

Move post_checkout_hook() to checkout.c and declare it in checkout.h
so that other subsystems can invoke the post-checkout hook without
depending on builtin/checkout.c.

This step in the series is entirely optional and is here primarily
for illustration.  We may later want to teach 'git worktree' to
trigger the 'post-checkout' hook, for example, in which case such
libification may turn out to be useful.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/checkout.c | 18 ------------------
 checkout.c         | 22 ++++++++++++++++++++++
 checkout.h         |  8 ++++++++
 3 files changed, 30 insertions(+), 18 deletions(-)

diff --git a/builtin/checkout.c b/builtin/checkout.c
index f13d70b224..b13e2ff205 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -124,24 +124,6 @@ static void branch_info_release(struct branch_info *info)
 	free(info->checkout);
 }
 
-static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
-			      int changed)
-{
-	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT_FORCE_SERIAL;
-
-	/*
-	 * "new_commit" can be NULL when checking out from the index before
-	 * a commit exists.
-	 */
-	strvec_pushl(&opt.args,
-		     oid_to_hex(old_commit ? &old_commit->object.oid : null_oid(the_hash_algo)),
-		     oid_to_hex(new_commit ? &new_commit->object.oid : null_oid(the_hash_algo)),
-		     changed ? "1" : "0",
-		     NULL);
-
-	return run_hooks_opt(the_repository, "post-checkout", &opt);
-}
-
 /*
  * Handle a tree object and determine if we need to recurse into the
  * tree (READ_TREE_RECURSIVE) or skip it (0).
diff --git a/checkout.c b/checkout.c
index 1588b116ee..d007648f50 100644
--- a/checkout.c
+++ b/checkout.c
@@ -1,6 +1,9 @@
 #define USE_THE_REPOSITORY_VARIABLE
 
 #include "git-compat-util.h"
+#include "commit.h"
+#include "hex.h"
+#include "hook.h"
 #include "object-name.h"
 #include "remote.h"
 #include "refspec.h"
@@ -8,6 +11,7 @@
 #include "checkout.h"
 #include "config.h"
 #include "strbuf.h"
+#include "strvec.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
@@ -73,3 +77,21 @@ char *unique_tracking_name(const char *name, struct object_id *oid,
 	}
 	return NULL;
 }
+
+int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
+		       int changed)
+{
+	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT_FORCE_SERIAL;
+
+	/*
+	 * "new_commit" can be NULL when checking out from the index before
+	 * a commit exists.
+	 */
+	strvec_pushl(&opt.args,
+		     oid_to_hex(old_commit ? &old_commit->object.oid : null_oid(the_hash_algo)),
+		     oid_to_hex(new_commit ? &new_commit->object.oid : null_oid(the_hash_algo)),
+		     changed ? "1" : "0",
+		     NULL);
+
+	return run_hooks_opt(the_repository, "post-checkout", &opt);
+}
diff --git a/checkout.h b/checkout.h
index 55920e7aeb..9c2f2449dc 100644
--- a/checkout.h
+++ b/checkout.h
@@ -3,6 +3,8 @@
 
 #include "hash.h"
 
+struct commit;
+
 /*
  * Check if the branch name uniquely matches a branch name on a remote
  * tracking branch.  Return the name of the remote if such a branch
@@ -12,4 +14,10 @@ char *unique_tracking_name(const char *name,
 			   struct object_id *oid,
 			   int *dwim_remotes_matched);
 
+/*
+ * Run the post-checkout hook.
+ */
+int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
+		       int changed);
+
 #endif /* CHECKOUT_H */
-- 
2.55.0-884-g76cf8659c2