From: Jiri Denemark <jdenemar@redhat.com>
Date: Fri, 3 Dec 2010 08:31:48 +0000 (+0100)
Subject: Change return value of VIR_DRV_SUPPORTS_FEATURE to bool
X-Git-Tag: v0.8.7~162
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4186f92935e6bb5057b2db14f47dfd817ab0ab84;p=thirdparty%2Flibvirt.git

Change return value of VIR_DRV_SUPPORTS_FEATURE to bool

virDrvSupportsFeature API is allowed to return -1 on error while all but
one uses of VIR_DRV_SUPPORTS_FEATURE only check for (non)zero return
value. Let's make this macro return zero on error, which is what
everyone expects anyway.
---

diff --git a/src/driver.h b/src/driver.h
index b770e5e569..75305fede5 100644
--- a/src/driver.h
+++ b/src/driver.h
@@ -47,17 +47,20 @@ typedef enum {
 
 
 /* Internal feature-detection macro.  Don't call drv->supports_feature
- * directly, because it may be NULL, use this macro instead.
+ * directly if you don't have to, because it may be NULL, use this macro
+ * instead.
  *
- * Note that you must check for errors.
+ * Note that this treats a possible error returned by drv->supports_feature
+ * the same as not supported. If you care about the error, call
+ * drv->supports_feature directly.
  *
  * Returns:
- *   >= 1  Feature is supported.
+ *   != 0  Feature is supported.
  *   0     Feature is not supported.
- *   -1    Error.
  */
-# define VIR_DRV_SUPPORTS_FEATURE(drv,conn,feature)                      \
-    ((drv)->supports_feature ? (drv)->supports_feature((conn),(feature)) : 0)
+# define VIR_DRV_SUPPORTS_FEATURE(drv,conn,feature)                         \
+    ((drv)->supports_feature ?                                              \
+        (drv)->supports_feature((conn), (feature)) > 0 : 0)
 
 typedef virDrvOpenStatus
         (*virDrvOpen)			(virConnectPtr conn,
diff --git a/src/libvirt.c b/src/libvirt.c
index b4951c233d..4188b452ea 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -1605,7 +1605,10 @@ virDrvSupportsFeature (virConnectPtr conn, int feature)
         return (-1);
     }
 
-    ret = VIR_DRV_SUPPORTS_FEATURE (conn->driver, conn, feature);
+    if (!conn->driver->supports_feature)
+        ret = 0;
+    else
+        ret = conn->driver->supports_feature(conn, feature);
 
     if (ret < 0)
         virDispatchError(conn);