[cheese] Check for a valid effect in CheeseEffect

[David King <davidk src gnome org>]

commit 357494f7206126419b883d5bf5ba17ce9b2a0052
Author: David King <amigadave amigadave com>
Date:   Sat Dec 10 23:31:08 2011 +0100

    Check for a valid effect in CheeseEffect
    
    Check that the effect passed to CheeseEffect functions is valid, and
    return NULL and print a critical warning otherwise.

 libcheese/cheese-effect.c |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)
---
diff --git a/libcheese/cheese-effect.c b/libcheese/cheese-effect.c
index a80672d..1f6c59e 100644
--- a/libcheese/cheese-effect.c
+++ b/libcheese/cheese-effect.c
@@ -162,6 +162,8 @@ cheese_effect_class_init (CheeseEffectClass *klass)
 const gchar *
 cheese_effect_get_name (CheeseEffect *effect)
 {
+  g_return_val_if_fail (CHEESE_IS_EFFECT (effect), NULL);
+
   return effect->priv->name;
 }
 
@@ -176,6 +178,8 @@ cheese_effect_get_name (CheeseEffect *effect)
 const gchar *
 cheese_effect_get_pipeline_desc (CheeseEffect *effect)
 {
+  g_return_val_if_fail (CHEESE_IS_EFFECT (effect), NULL);
+
   return effect->priv->pipeline_desc;
 }
 
@@ -190,6 +194,8 @@ cheese_effect_get_pipeline_desc (CheeseEffect *effect)
 gboolean
 cheese_effect_is_preview_connected (CheeseEffect *effect)
 {
+  g_return_val_if_fail (CHEESE_IS_EFFECT (effect), FALSE);
+
   return effect->priv->control_valve != NULL;
 }
 
@@ -202,6 +208,8 @@ cheese_effect_is_preview_connected (CheeseEffect *effect)
 void
 cheese_effect_enable_preview (CheeseEffect *effect)
 {
+  g_return_if_fail (CHEESE_IS_EFFECT (effect));
+
   g_object_set (G_OBJECT (effect->priv->control_valve), "drop", FALSE, NULL);
 }
 
@@ -214,6 +222,8 @@ cheese_effect_enable_preview (CheeseEffect *effect)
 void
 cheese_effect_disable_preview (CheeseEffect *effect)
 {
+  g_return_if_fail (CHEESE_IS_EFFECT (effect));
+
   g_object_set (G_OBJECT (effect->priv->control_valve), "drop", TRUE, NULL);
 }