shared: add nm_pdirect_hash()/nm_pdirect_equal()

This follows a pointer to a pointer and compares them. In a sense
it's like nm_pstr_*(), which follow a pointer to a string. However,
these functions use direct pointer comparison.

The purpose is when you hash a key that has as first field a pointer
value (and then compare them by pointer equality).

2 files changed, 31 insertions, 0 deletions

diff --git a/shared/nm-glib-aux/nm-hash-utils.c b/shared/nm-glib-aux/nm-hash-utils.c
index b2ae75e3fc..a6158269d4 100644
--- a/shared/nm-glib-aux/nm-hash-utils.c
+++ b/shared/nm-glib-aux/nm-hash-utils.c
@@ -199,3 +199,25 @@ nm_pstr_equal (gconstpointer a, gconstpointer b)
 	           && s2
 	           && nm_streq0 (*s1, *s2));
 }
+
+guint
+nm_pdirect_hash (gconstpointer p)
+{
+	const void *const*s = p;
+
+	if (!s)
+		return nm_hash_static (1852748873u);
+	return nm_direct_hash (*s);
+}
+
+gboolean
+nm_pdirect_equal (gconstpointer a, gconstpointer b)
+{
+	const void *const*s1 = a;
+	const void *const*s2 = b;
+
+	return    (s1 == s2)
+	       || (   s1
+	           && s2
+	           && *s1 == *s2);
+}
diff --git a/shared/nm-glib-aux/nm-hash-utils.h b/shared/nm-glib-aux/nm-hash-utils.h
index 472cfec8cc..f13e0b6d56 100644
--- a/shared/nm-glib-aux/nm-hash-utils.h
+++ b/shared/nm-glib-aux/nm-hash-utils.h
@@ -290,6 +290,15 @@ gboolean nm_pstr_equal (gconstpointer a, gconstpointer b);
 
 /*****************************************************************************/
 
+/* this hashes/compares the pointer value that we point to. Basically,
+ * (((const void *const*) a) == ((const void *const*) b)). */
+
+guint nm_pdirect_hash (gconstpointer p);
+
+gboolean nm_pdirect_equal (gconstpointer a, gconstpointer b);
+
+/*****************************************************************************/
+
 #define NM_HASH_OBFUSCATE_PTR_FMT "%016" G_GINT64_MODIFIER "x"
 
 /* sometimes we want to log a pointer directly, for providing context/information about