[vlc-devel] [PATCH 1/3] variables: add VLC_VAR_COMPARE_EXCHANGE

[Hugo Beauzée-Luyssen]

From: Thomas Guillem <thomas at gllm.fr>

Behaves like atomic_compare_exchange but with vlc variables.
---
 include/vlc_variables.h | 2 ++
 src/misc/variables.c    | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/include/vlc_variables.h b/include/vlc_variables.h
index 83752b171f..15f5e7e803 100644
--- a/include/vlc_variables.h
+++ b/include/vlc_variables.h
@@ -101,6 +101,8 @@
 #define VLC_VAR_CHOICESCOUNT        0x0026
 #define VLC_VAR_SETMINMAX           0x0027
 
+#define VLC_VAR_COMPARE_EXCHANGE    0x0028
+
 /**@}*/
 
 /** \defgroup var_GetAndSet Variable actions
diff --git a/src/misc/variables.c b/src/misc/variables.c
index 121ef5ea70..47131587e2 100644
--- a/src/misc/variables.c
+++ b/src/misc/variables.c
@@ -559,6 +559,14 @@ int var_Change( vlc_object_t *p_this, const char *psz_name,
             p_var->choices_text.p_values = NULL;
             TriggerListCallback(p_this, p_var, psz_name, VLC_VAR_CLEARCHOICES, NULL);
             break;
+        case VLC_VAR_COMPARE_EXCHANGE:
+            if( p_var->ops->pf_cmp( p_var->val, *p_val ) != 0 )
+            {
+                ret = VLC_EBADVAR;
+                break;
+            }
+            p_val = p_val2;
+            /* Fall through */
         case VLC_VAR_SETVALUE:
             /* Duplicate data if needed */
             newval = *p_val;
-- 
2.11.0