* libvirt/libvirt.mli, libvirt/libvirt.ml: New error numbers

	  in base libvirt.
	* libvirt/libvirt_c.c: Gracefully handle the case where libvirt
	  throws an error number we have not heard of before (eg. when
	  dynamic linking with newer libvirt).
	* configure.ac: Check <libvirt/virterror.h> exists.
	* configure.ac: Version 0.3.3.4.

3 files changed, 108 insertions, 21 deletions

diff --git a/libvirt/libvirt.ml b/libvirt/libvirt.ml
index 586aa7b..69e1c0d 100644
--- a/libvirt/libvirt.ml
+++ b/libvirt/libvirt.ml
@@ -260,6 +260,8 @@ struct
     | VIR_WAR_NO_NETWORK
     | VIR_ERR_NO_DOMAIN
     | VIR_ERR_NO_NETWORK
+    | VIR_ERR_INVALID_MAC
+    | VIR_ERR_UNKNOWN of int
 
   let string_of_code = function
     | VIR_ERR_OK -> "VIR_ERR_OK"
@@ -306,16 +308,8 @@ struct
     | VIR_WAR_NO_NETWORK -> "VIR_WAR_NO_NETWORK"
     | VIR_ERR_NO_DOMAIN -> "VIR_ERR_NO_DOMAIN"
     | VIR_ERR_NO_NETWORK -> "VIR_ERR_NO_NETWORK"
-
-  type level =
-    | VIR_ERR_NONE
-    | VIR_ERR_WARNING
-    | VIR_ERR_ERROR
-
-  let string_of_level = function
-    | VIR_ERR_NONE -> "VIR_ERR_NONE"
-    | VIR_ERR_WARNING -> "VIR_ERR_WARNING"
-    | VIR_ERR_ERROR -> "VIR_ERR_ERROR"
+    | VIR_ERR_INVALID_MAC -> "VIR_ERR_INVALID_MAC"
+    | VIR_ERR_UNKNOWN i -> "VIR_ERR_" ^ string_of_int i
 
   type domain =
     | VIR_FROM_NONE
@@ -333,6 +327,9 @@ struct
     | VIR_FROM_TEST
     | VIR_FROM_REMOTE
     | VIR_FROM_OPENVZ
+    | VIR_FROM_XENXM
+    | VIR_FROM_STATS_LINUX
+    | VIR_FROM_UNKNOWN of int
 
   let string_of_domain = function
     | VIR_FROM_NONE -> "VIR_FROM_NONE"
@@ -350,6 +347,21 @@ struct
     | VIR_FROM_TEST -> "VIR_FROM_TEST"
     | VIR_FROM_REMOTE -> "VIR_FROM_REMOTE"
     | VIR_FROM_OPENVZ -> "VIR_FROM_OPENVZ"
+    | VIR_FROM_XENXM -> "VIR_FROM_XENXM"
+    | VIR_FROM_STATS_LINUX -> "VIR_FROM_STATS_LINUX"
+    | VIR_FROM_UNKNOWN i -> "VIR_FROM_" ^ string_of_int i
+
+  type level =
+    | VIR_ERR_NONE
+    | VIR_ERR_WARNING
+    | VIR_ERR_ERROR
+    | VIR_ERR_UNKNOWN_LEVEL of int
+
+  let string_of_level = function
+    | VIR_ERR_NONE -> "VIR_ERR_NONE"
+    | VIR_ERR_WARNING -> "VIR_ERR_WARNING"
+    | VIR_ERR_ERROR -> "VIR_ERR_ERROR"
+    | VIR_ERR_UNKNOWN_LEVEL i -> "VIR_ERR_LEVEL_" ^ string_of_int i
 
   type t = {
     code : code;
diff --git a/libvirt/libvirt.mli b/libvirt/libvirt.mli
index 1d9da1e..aa4b9f4 100644
--- a/libvirt/libvirt.mli
+++ b/libvirt/libvirt.mli
@@ -463,18 +463,13 @@ sig
     | VIR_WAR_NO_NETWORK
     | VIR_ERR_NO_DOMAIN
     | VIR_ERR_NO_NETWORK
+    | VIR_ERR_INVALID_MAC
+	(* ^^ NB: If you add a variant you MUST edit libvirt_c.c:MAX_VIR_* *)
+    | VIR_ERR_UNKNOWN of int
 	(** See [<libvirt/virterror.h>] for meaning of these codes. *)
 
   val string_of_code : code -> string
 
-  type level =
-    | VIR_ERR_NONE
-    | VIR_ERR_WARNING
-    | VIR_ERR_ERROR
-	(** No error, a warning or an error. *)
-
-  val string_of_level : level -> string
-
   type domain =
     | VIR_FROM_NONE
     | VIR_FROM_XEN
@@ -491,10 +486,24 @@ sig
     | VIR_FROM_TEST
     | VIR_FROM_REMOTE
     | VIR_FROM_OPENVZ
+    | VIR_FROM_XENXM
+    | VIR_FROM_STATS_LINUX
+	(* ^^ NB: If you add a variant you MUST edit libvirt_c.c: MAX_VIR_* *)
+    | VIR_FROM_UNKNOWN of int
 	(** Subsystem / driver which produced the error. *)
 
   val string_of_domain : domain -> string
 
+  type level =
+    | VIR_ERR_NONE
+    | VIR_ERR_WARNING
+    | VIR_ERR_ERROR
+	(* ^^ NB: If you add a variant you MUST edit libvirt_c.c: MAX_VIR_* *)
+    | VIR_ERR_UNKNOWN_LEVEL of int
+	(** No error, a warning or an error. *)
+
+  val string_of_level : level -> string
+
   type t = {
     code : code;			(** Error code. *)
     domain : domain;			(** Origin of the error. *)
diff --git a/libvirt/libvirt_c.c b/libvirt/libvirt_c.c
index 9e2182b..a2bb1ad 100644
--- a/libvirt/libvirt_c.c
+++ b/libvirt/libvirt_c.c
@@ -1795,6 +1795,72 @@ _raise_virterror (virConnectPtr conn, const char *fn)
   CAMLreturn (Val_unit);
 }
 
+/* Convert the virErrorNumber, virErrorDomain and virErrorLevel enums
+ * into values (longs because they are variants in OCaml).
+ *
+ * The enum values are part of the libvirt ABI so they cannot change,
+ * which means that we can convert these numbers directly into
+ * OCaml variants (which use the same ordering) very fast.
+ *
+ * The tricky part here is when we are linked to a newer version of
+ * libvirt than the one we were compiled against.  If the newer libvirt
+ * generates an error code which we don't know about then we need
+ * to convert it into VIR_*_UNKNOWN (code).
+ */
+
+#define MAX_VIR_CODE 44 /* VIR_ERR_INVALID_MAC */
+#define MAX_VIR_DOMAIN 16 /* VIR_FROM_STATS_LINUX */
+#define MAX_VIR_LEVEL VIR_ERR_ERROR
+
+static inline value
+Val_err_number (virErrorNumber code)
+{
+  CAMLparam0 ();
+  CAMLlocal1 (rv);
+
+  if (0 <= code && code <= MAX_VIR_CODE)
+    rv = Val_int (code);
+  else {
+    rv = caml_alloc (1, 0);	/* VIR_ERR_UNKNOWN (code) */
+    Store_field (rv, 0, Val_int (code));
+  }
+
+  CAMLreturn (rv);
+}
+
+static inline value
+Val_err_domain (virErrorDomain code)
+{
+  CAMLparam0 ();
+  CAMLlocal1 (rv);
+
+  if (0 <= code && code <= MAX_VIR_DOMAIN)
+    rv = Val_int (code);
+  else {
+    rv = caml_alloc (1, 0);	/* VIR_FROM_UNKNOWN (code) */
+    Store_field (rv, 0, Val_int (code));
+  }
+
+  CAMLreturn (rv);
+}
+
+static inline value
+Val_err_level (virErrorLevel code)
+{
+  CAMLparam0 ();
+  CAMLlocal1 (rv);
+
+  if (0 <= code && code <= MAX_VIR_LEVEL)
+    rv = Val_int (code);
+  else {
+    rv = caml_alloc (1, 0);	/* VIR_ERR_UNKNOWN_LEVEL (code) */
+    Store_field (rv, 0, Val_int (code));
+  }
+
+  CAMLreturn (rv);
+}
+
+/* Convert a virterror to a value. */
 static value
 Val_virterror (virErrorPtr err)
 {
@@ -1802,11 +1868,11 @@ Val_virterror (virErrorPtr err)
   CAMLlocal3 (rv, connv, optv);
 
   rv = caml_alloc (12, 0);
-  Store_field (rv, 0, Val_int (err->code));
-  Store_field (rv, 1, Val_int (err->domain));
+  Store_field (rv, 0, Val_err_number (err->code));
+  Store_field (rv, 1, Val_err_domain (err->domain));
   Store_field (rv, 2,
 	       Val_opt (err->message, (Val_ptr_t) caml_copy_string));
-  Store_field (rv, 3, Val_int (err->level));
+  Store_field (rv, 3, Val_err_level (err->level));
 
   /* conn, dom and net fields, all optional */
   if (err->conn) {