core: add handle_db_is_empty() function

Implements a function that checks if a handle database is empty, i.e.
all pointers stored in the database are NULL.

Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Jerome Forissier <jerome@forissier.org>
Signed-off-by: Balint Dobszay <balint.dobszay@arm.com>

2 files changed, 19 insertions, 0 deletions

diff --git a/core/include/kernel/handle.h b/core/include/kernel/handle.h
index 6cca2dbf..eb4375dd 100644
--- a/core/include/kernel/handle.h
+++ b/core/include/kernel/handle.h
@@ -1,10 +1,12 @@
 /* SPDX-License-Identifier: BSD-2-Clause */
 /*
  * Copyright (c) 2014, Linaro Limited
+ * Copyright (c) 2020, Arm Limited
  */
 #ifndef KERNEL_HANDLE_H
 #define KERNEL_HANDLE_H
 
+#include <stdbool.h>
 #include <stdint.h>
 
 struct handle_db {
@@ -22,6 +24,9 @@ struct handle_db {
  */
 void handle_db_destroy(struct handle_db *db, void (*ptr_destructor)(void *ptr));
 
+/* Checks if the associated pointers of all handles in the database are NULL. */
+bool handle_db_is_empty(struct handle_db *db);
+
 /*
  * Allocates a new handle and assigns the supplied pointer to it,
  * ptr must not be NULL.
diff --git a/core/kernel/handle.c b/core/kernel/handle.c
index 131c7059..96f01cb3 100644
--- a/core/kernel/handle.c
+++ b/core/kernel/handle.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: BSD-2-Clause
 /*
  * Copyright (c) 2014, Linaro Limited
+ * Copyright (c) 2020, Arm Limited
  */
 #include <stdlib.h>
 #include <string.h>
@@ -30,6 +31,19 @@ void handle_db_destroy(struct handle_db *db, void (*ptr_destructor)(void *ptr))
 	}
 }
 
+bool handle_db_is_empty(struct handle_db *db)
+{
+	size_t n = 0;
+
+	if (db) {
+		for (n = 0; n < db->max_ptrs; n++) {
+			if (db->ptrs[n])
+				return false;
+		}
+	}
+	return true;
+}
+
 int handle_get(struct handle_db *db, void *ptr)
 {
 	size_t n;