migration: Replace migration's JSON writer by the general one

Commit 8118f0950f "migration: Append JSON description of migration
stream" needs a JSON writer.  The existing qobject_to_json() wasn't a
good fit, because it requires building a QObject to convert.  Instead,
migration got its very own JSON writer, in commit 190c882ce2 "QJSON:
Add JSON writer".  It tacitly limits numbers to int64_t, and strings
contents to characters that don't need escaping, unlike
qobject_to_json().

The previous commit factored the JSON writer out of qobject_to_json().
Replace migration's JSON writer by it.

Cc: Juan Quintela <quintela@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20201211171152.146877-17-armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

1 files changed, 27 insertions, 25 deletions

diff --git a/migration/vmstate.c b/migration/vmstate.c
index e9d2aef66b..05f87cdddc 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -14,14 +14,14 @@
 #include "migration.h"
 #include "migration/vmstate.h"
 #include "savevm.h"
+#include "qapi/qmp/json-writer.h"
 #include "qemu-file.h"
 #include "qemu/bitops.h"
 #include "qemu/error-report.h"
 #include "trace.h"
-#include "qjson.h"
 
 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
-                                   void *opaque, QJSON *vmdesc);
+                                   void *opaque, JSONWriter *vmdesc);
 static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
                                    void *opaque);
 
@@ -249,7 +249,8 @@ static bool vmsd_can_compress(const VMStateField *field)
     return true;
 }
 
-static void vmsd_desc_field_start(const VMStateDescription *vmsd, QJSON *vmdesc,
+static void vmsd_desc_field_start(const VMStateDescription *vmsd,
+                                  JSONWriter *vmdesc,
                                   const VMStateField *field, int i, int max)
 {
     char *name, *old_name;
@@ -270,25 +271,26 @@ static void vmsd_desc_field_start(const VMStateDescription *vmsd, QJSON *vmdesc,
         g_free(old_name);
     }
 
-    json_start_object(vmdesc, NULL);
-    json_prop_str(vmdesc, "name", name);
+    json_writer_start_object(vmdesc, NULL);
+    json_writer_str(vmdesc, "name", name);
     if (is_array) {
         if (can_compress) {
-            json_prop_int(vmdesc, "array_len", max);
+            json_writer_int64(vmdesc, "array_len", max);
         } else {
-            json_prop_int(vmdesc, "index", i);
+            json_writer_int64(vmdesc, "index", i);
         }
     }
-    json_prop_str(vmdesc, "type", vmfield_get_type_name(field));
+    json_writer_str(vmdesc, "type", vmfield_get_type_name(field));
 
     if (field->flags & VMS_STRUCT) {
-        json_start_object(vmdesc, "struct");
+        json_writer_start_object(vmdesc, "struct");
     }
 
     g_free(name);
 }
 
-static void vmsd_desc_field_end(const VMStateDescription *vmsd, QJSON *vmdesc,
+static void vmsd_desc_field_end(const VMStateDescription *vmsd,
+                                JSONWriter *vmdesc,
                                 const VMStateField *field, size_t size, int i)
 {
     if (!vmdesc) {
@@ -297,11 +299,11 @@ static void vmsd_desc_field_end(const VMStateDescription *vmsd, QJSON *vmdesc,
 
     if (field->flags & VMS_STRUCT) {
         /* We printed a struct in between, close its child object */
-        json_end_object(vmdesc);
+        json_writer_end_object(vmdesc);
     }
 
-    json_prop_int(vmdesc, "size", size);
-    json_end_object(vmdesc);
+    json_writer_int64(vmdesc, "size", size);
+    json_writer_end_object(vmdesc);
 }
 
 
@@ -316,13 +318,13 @@ bool vmstate_save_needed(const VMStateDescription *vmsd, void *opaque)
 
 
 int vmstate_save_state(QEMUFile *f, const VMStateDescription *vmsd,
-                       void *opaque, QJSON *vmdesc_id)
+                       void *opaque, JSONWriter *vmdesc_id)
 {
     return vmstate_save_state_v(f, vmsd, opaque, vmdesc_id, vmsd->version_id);
 }
 
 int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
-                         void *opaque, QJSON *vmdesc, int version_id)
+                         void *opaque, JSONWriter *vmdesc, int version_id)
 {
     int ret = 0;
     const VMStateField *field = vmsd->fields;
@@ -339,9 +341,9 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
     }
 
     if (vmdesc) {
-        json_prop_str(vmdesc, "vmsd_name", vmsd->name);
-        json_prop_int(vmdesc, "version", version_id);
-        json_start_array(vmdesc, "fields");
+        json_writer_str(vmdesc, "vmsd_name", vmsd->name);
+        json_writer_int64(vmdesc, "version", version_id);
+        json_writer_start_array(vmdesc, "fields");
     }
 
     while (field->name) {
@@ -353,7 +355,7 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
             int i, n_elems = vmstate_n_elems(opaque, field);
             int size = vmstate_size(opaque, field);
             int64_t old_offset, written_bytes;
-            QJSON *vmdesc_loop = vmdesc;
+            JSONWriter *vmdesc_loop = vmdesc;
 
             trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems);
             if (field->flags & VMS_POINTER) {
@@ -413,7 +415,7 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDescription *vmsd,
     }
 
     if (vmdesc) {
-        json_end_array(vmdesc);
+        json_writer_end_array(vmdesc);
     }
 
     ret = vmstate_subsection_save(f, vmsd, opaque, vmdesc);
@@ -491,7 +493,7 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
 }
 
 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
-                                   void *opaque, QJSON *vmdesc)
+                                   void *opaque, JSONWriter *vmdesc)
 {
     const VMStateDescription **sub = vmsd->subsections;
     bool vmdesc_has_subsections = false;
@@ -507,11 +509,11 @@ static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
             if (vmdesc) {
                 /* Only create subsection array when we have any */
                 if (!vmdesc_has_subsections) {
-                    json_start_array(vmdesc, "subsections");
+                    json_writer_start_array(vmdesc, "subsections");
                     vmdesc_has_subsections = true;
                 }
 
-                json_start_object(vmdesc, NULL);
+                json_writer_start_object(vmdesc, NULL);
             }
 
             qemu_put_byte(f, QEMU_VM_SUBSECTION);
@@ -525,14 +527,14 @@ static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *vmsd,
             }
 
             if (vmdesc) {
-                json_end_object(vmdesc);
+                json_writer_end_object(vmdesc);
             }
         }
         sub++;
     }
 
     if (vmdesc_has_subsections) {
-        json_end_array(vmdesc);
+        json_writer_end_array(vmdesc);
     }
 
     return ret;