hook: move is_known_hook() to hook.c for wider use

Move is_known_hook() from builtin/hook.c (static) into hook.c and
export it via hook.h so it can be reused.

Make it return bool and the iterator `h` for clarity (iterate hooks).

The next commit will use this to reject hook friendly-names that
collide with known event names.

Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: 10ne1

Makefile

@@ -2663,7 +2663,7 @@ git$X: git.o GIT-LDFLAGS $(BUILTIN_OBJS) $(GITLIBS)
 
 help.sp help.s help.o: command-list.h
 builtin/bugreport.sp builtin/bugreport.s builtin/bugreport.o: hook-list.h
-builtin/hook.sp builtin/hook.s builtin/hook.o: hook-list.h
+hook.sp hook.s hook.o: hook-list.h
 
 builtin/help.sp builtin/help.s builtin/help.o: config-list.h GIT-PREFIX
 builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \

builtin/hook.c

@@ -4,7 +4,6 @@
 #include "environment.h"
 #include "gettext.h"
 #include "hook.h"
-#include "hook-list.h"
 #include "parse-options.h"
 
 #define BUILTIN_HOOK_RUN_USAGE \
@@ -13,15 +12,6 @@
 #define BUILTIN_HOOK_LIST_USAGE \
 	N_("git hook list [--allow-unknown-hook-name] [-z] [--show-scope] <hook-name>")
 
-static int is_known_hook(const char *name)
-{
-	const char **p;
-	for (p = hook_name_list; *p; p++)
-		if (!strcmp(*p, name))
-			return 1;
-	return 0;
-}
-
 static const char * const builtin_hook_usage[] = {
 	BUILTIN_HOOK_RUN_USAGE,
 	BUILTIN_HOOK_LIST_USAGE,

hook.c

@@ -5,13 +5,23 @@
 #include "environment.h"
 #include "gettext.h"
 #include "hook.h"
+#include "hook-list.h"
 #include "parse.h"
 #include "path.h"
 #include "run-command.h"
 #include "setup.h"
 #include "strbuf.h"
 #include "strmap.h"
 
+bool is_known_hook(const char *name)
+{
+	const char **h;
+	for (h = hook_name_list; *h; h++)
+		if (!strcmp(*h, name))
+			return true;
+	return false;
+}
+
 const char *find_hook(struct repository *r, const char *name)
 {
 	static struct strbuf path = STRBUF_INIT;

hook.h

@@ -234,6 +234,12 @@ void hook_free(void *p, const char *str);
  */
 void hook_cache_clear(struct strmap *cache);
 
+/**
+ * Returns true if `name` is a recognized hook event name
+ * (e.g. "pre-commit", "post-receive").
+ */
+bool is_known_hook(const char *name);
+
 /**
  * Returns the path to the hook file, or NULL if the hook is missing
  * or disabled. Note that this points to static storage that will be