qerror: add qerror_report_err()

This provides a bridge between Error (new error mechanism) and QError (old error
mechanism).  Errors can be propagated whereas QError cannot.

The minor evilness avoids layering violations.  Since QError should go away RSN,
it seems like a reasonable hack.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>

qerror.c

@@ -482,6 +482,39 @@ void qerror_report_internal(const char *file, int linenr, const char *func,
     }
 }
 
+/* Evil... */
+struct Error
+{
+    QDict *obj;
+    const char *fmt;
+    char *msg;
+};
+
+void qerror_report_err(Error *err)
+{
+    QError *qerr;
+    int i;
+
+    qerr = qerror_new();
+    loc_save(&qerr->loc);
+    QINCREF(err->obj);
+    qerr->error = err->obj;
+
+    for (i = 0; qerror_table[i].error_fmt; i++) {
+        if (strcmp(qerror_table[i].error_fmt, err->fmt) == 0) {
+            qerr->entry = &qerror_table[i];
+            break;
+        }
+    }
+
+    if (monitor_cur_is_qmp()) {
+        monitor_set_error(cur_mon, qerr);
+    } else {
+        qerror_print(qerr);
+        QDECREF(qerr);
+    }
+}
+
 /**
  * qobject_to_qerror(): Convert a QObject into a QError
  */

qerror.h

@@ -15,6 +15,7 @@
 #include "qdict.h"
 #include "qstring.h"
 #include "qemu-error.h"
+#include "error.h"
 #include <stdarg.h>
 
 typedef struct QErrorStringTable {
@@ -39,6 +40,7 @@ QString *qerror_human(const QError *qerror);
 void qerror_print(QError *qerror);
 void qerror_report_internal(const char *file, int linenr, const char *func,
                             const char *fmt, ...) GCC_FMT_ATTR(4, 5);
+void qerror_report_err(Error *err);
 QString *qerror_format(const char *fmt, QDict *error);
 #define qerror_report(fmt, ...) \
     qerror_report_internal(__FILE__, __LINE__, __func__, fmt, ## __VA_ARGS__)