[libvirt] [PATCH v2 2/7] internal: introduce macro helpers to check flag requirements

[Pavel Hrdina]

Similar to VIR_EXLUSIVE_FLAGS, it will error out if flag requirement is
not met.

Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
---
 src/internal.h | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/src/internal.h b/src/internal.h
index eb8d231..6363e58 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -371,6 +371,49 @@
         goto LABEL;                                                         \
     }
 
+/* Macros to help dealing with flag requirements. */
+
+/**
+ * VIR_REQUIRE_FLAG_RET:
+ *
+ * @FLAG1: First flag to be checked.
+ * @FLAG2: Second flag that is required by first flag.
+ * @RET: Return value.
+ *
+ * Check whether required flag is set.  The checked flags are compared
+ * with flags variable.
+ *
+ * This helper does an early return and therefore it has to be called
+ * before anything that would require cleanup.
+ */
+# define VIR_REQUIRE_FLAG_RET(FLAG1, FLAG2, RET)                            \
+    if ((flags & FLAG1) && !(flags & FLAG2)) {                              \
+        virReportInvalidArg(ctl,                                            \
+                            _("Flag '%s' is required by flag '%s'"),        \
+                            #FLAG2, #FLAG1);                                \
+        return RET;                                                         \
+    }
+
+/**
+ * VIR_REQUIRE_FLAG_GOTO:
+ *
+ * @FLAG1: First flag to be checked.
+ * @FLAG2: Second flag that is required by first flag.
+ * @LABEL: Label to jump to.
+ *
+ * Check whether required flag is set.  The checked flags are compared
+ * with flags variable.
+ *
+ * Returns nothing.  Jumps to a label if required flag is not set.
+ */
+# define VIR_REQUIRE_FLAG_GOTO(FLAG1, FLAG2, LABEL)                         \
+    if ((flags & FLAG1) && !(flags & FLAG2)) {                              \
+        virReportInvalidArg(ctl,                                            \
+                            _("Flag '%s' is required by flag '%s'"),        \
+                            #FLAG2, #FLAG1);                                \
+        goto LABEL;                                                         \
+    }
+
 # define virCheckNonNullArgReturn(argname, retval)  \
     do {                                            \
         if (argname == NULL) {                      \
-- 
2.0.5