[Qemu-devel] [PATCH 2/6] snapshot: add error set function

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

  Added two function which will try replace the error if it is
already set, so only last error is reported.

Signed-off-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
---
 error.c |   23 +++++++++++++++++++++++
 error.h |    9 +++++++++
 2 files changed, 32 insertions(+), 0 deletions(-)

diff --git a/error.c b/error.c
index 128d88c..5a82f8e 100644
--- a/error.c
+++ b/error.c
@@ -43,6 +43,29 @@ void error_set(Error **errp, ErrorClass err_class, const char *fmt, ...)
     *errp = err;
 }
 
+void error_set_replace(Error **errp, ErrorClass err_class, const char *fmt, ...)
+{
+    Error *err;
+    va_list ap;
+
+    if (errp == NULL) {
+        return;
+    }
+    if (*errp != NULL) {
+        error_free(*errp);
+        *errp = NULL;
+    }
+
+    err = g_malloc0(sizeof(*err));
+
+    va_start(ap, fmt);
+    err->msg = g_strdup_vprintf(fmt, ap);
+    va_end(ap);
+    err->err_class = err_class;
+
+    *errp = err;
+}
+
 void error_set_errno(Error **errp, int os_errno, ErrorClass err_class,
                      const char *fmt, ...)
 {
diff --git a/error.h b/error.h
index 4d52e73..8039408 100644
--- a/error.h
+++ b/error.h
@@ -29,6 +29,9 @@ typedef struct Error Error;
  */
 void error_set(Error **err, ErrorClass err_class, const char *fmt, ...) GCC_FMT_ATTR(3, 4);
 
+void error_set_replace(Error **err, ErrorClass err_class, const char *fmt, ...)
+GCC_FMT_ATTR(3, 4);
+
 /**
  * Set an indirect pointer to an error given a ErrorClass value and a
  * printf-style human message, followed by a strerror() string if
@@ -43,6 +46,12 @@ void error_set_errno(Error **err, int os_error, ErrorClass err_class, const char
     error_set(err, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__)
 #define error_setg_errno(err, os_error, fmt, ...) \
     error_set_errno(err, os_error, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__)
+#define error_setg_replace(err, fmt, ...) do {                     \
+    if (*err != NULL) { \
+        error_free(*err); \
+     } \
+    error_set(err, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__); \
+} while (/*CONSTCOND*/0)
 
 /**
  * Returns true if an indirect pointer to an error is pointing to a valid
-- 
1.7.1