diff mbox series

[PULL,04/17] qcow2: Use a GString in report_unsupported_feature()

Message ID 20200206125132.594625-5-mreitz@redhat.com
State New
Headers show
Series [PULL,01/17] qcow2: Assert that host cluster offsets fit in L2 table entries | expand

Commit Message

Max Reitz Feb. 6, 2020, 12:51 p.m. UTC 
From: Alberto Garcia <berto@igalia.com>

This is a bit more efficient than having to allocate and free memory
for each item.

The default size (60) is enough for all the existing incompatible
features or the "Unknown incompatible feature" message.

Suggested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 20200115135626.19442-1-berto@igalia.com
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)
diff mbox series

Patch

diff --git a/block/qcow2.c b/block/qcow2.c
index cef9d72b3a..e29fc07068 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -453,16 +453,15 @@  static void cleanup_unknown_header_ext(BlockDriverState *bs)
 static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
                                        uint64_t mask)
 {
-    char *features = g_strdup("");
-    char *old;
+    g_autoptr(GString) features = g_string_sized_new(60);
 
     while (table && table->name[0] != '\0') {
         if (table->type == QCOW2_FEAT_TYPE_INCOMPATIBLE) {
             if (mask & (1ULL << table->bit)) {
-                old = features;
-                features = g_strdup_printf("%s%s%.46s", old, *old ? ", " : "",
-                                           table->name);
-                g_free(old);
+                if (features->len > 0) {
+                    g_string_append(features, ", ");
+                }
+                g_string_append_printf(features, "%.46s", table->name);
                 mask &= ~(1ULL << table->bit);
             }
         }
@@ -470,14 +469,14 @@  static void report_unsupported_feature(Error **errp, Qcow2Feature *table,
     }
 
     if (mask) {
-        old = features;
-        features = g_strdup_printf("%s%sUnknown incompatible feature: %" PRIx64,
-                                   old, *old ? ", " : "", mask);
-        g_free(old);
+        if (features->len > 0) {
+            g_string_append(features, ", ");
+        }
+        g_string_append_printf(features,
+                               "Unknown incompatible feature: %" PRIx64, mask);
     }
 
-    error_setg(errp, "Unsupported qcow2 feature(s): %s", features);
-    g_free(features);
+    error_setg(errp, "Unsupported qcow2 feature(s): %s", features->str);
 }
 
 /*