qapi/qapi-clone-visitor.c

   1 /*
   2  * Copy one QAPI object to another
   3  *
   4  * Copyright (C) 2016 Red Hat, Inc.
   5  *
   6  * This work is licensed under the terms of the GNU GPL, version 2 or later.
   7  * See the COPYING file in the top-level directory.
   8  *
   9  */
  10
  11 #include "qemu/osdep.h"
  12 #include "qapi/clone-visitor.h"
  13 #include "qapi/visitor-impl.h"
  14 #include "qapi/error.h"
  15
  16 struct QapiCloneVisitor {
  17     Visitor visitor;
  18     size_t depth;
  19 };
  20
  21 static QapiCloneVisitor *to_qcv(Visitor *v)
  22 {
  23     return container_of(v, QapiCloneVisitor, visitor);
  24 }
  25
  26 static void qapi_clone_start_struct(Visitor *v, const char *name, void **obj,
  27                                     size_t size, Error **errp)
  28 {
  29     QapiCloneVisitor *qcv = to_qcv(v);
  30
  31     if (!obj) {
  32         assert(qcv->depth);
  33         /* Only possible when visiting an alternate's object
  34          * branch. Nothing further to do here, since the earlier
  35          * visit_start_alternate() already copied memory. */
  36         return;
  37     }
  38
  39     *obj = g_memdup(*obj, size);
  40     qcv->depth++;
  41 }
  42
  43 static void qapi_clone_end(Visitor *v, void **obj)
  44 {
  45     QapiCloneVisitor *qcv = to_qcv(v);
  46
  47     assert(qcv->depth);
  48     if (obj) {
  49         qcv->depth--;
  50     }
  51 }
  52
  53 static void qapi_clone_start_list(Visitor *v, const char *name,
  54                                   GenericList **listp, size_t size,
  55                                   Error **errp)
  56 {
  57     qapi_clone_start_struct(v, name, (void **)listp, size, errp);
  58 }
  59
  60 static GenericList *qapi_clone_next_list(Visitor *v, GenericList *tail,
  61                                          size_t size)
  62 {
  63     QapiCloneVisitor *qcv = to_qcv(v);
  64
  65     assert(qcv->depth);
  66     /* Unshare the tail of the list cloned by g_memdup() */
  67     tail->next = g_memdup(tail->next, size);
  68     return tail->next;
  69 }
  70
  71 static void qapi_clone_start_alternate(Visitor *v, const char *name,
  72                                        GenericAlternate **obj, size_t size,
  73                                        Error **errp)
  74 {
  75     qapi_clone_start_struct(v, name, (void **)obj, size, errp);
  76 }
  77
  78 static void qapi_clone_type_int64(Visitor *v, const char *name, int64_t *obj,
  79                                    Error **errp)
  80 {
  81     QapiCloneVisitor *qcv = to_qcv(v);
  82
  83     assert(qcv->depth);
  84     /* Value was already cloned by g_memdup() */
  85 }
  86
  87 static void qapi_clone_type_uint64(Visitor *v, const char *name,
  88                                     uint64_t *obj, Error **errp)
  89 {
  90     QapiCloneVisitor *qcv = to_qcv(v);
  91
  92     assert(qcv->depth);
  93     /* Value was already cloned by g_memdup() */
  94 }
  95
  96 static void qapi_clone_type_bool(Visitor *v, const char *name, bool *obj,
  97                                   Error **errp)
  98 {
  99     QapiCloneVisitor *qcv = to_qcv(v);
 100
 101     assert(qcv->depth);
 102     /* Value was already cloned by g_memdup() */
 103 }
 104
 105 static void qapi_clone_type_str(Visitor *v, const char *name, char **obj,
 106                                  Error **errp)
 107 {
 108     QapiCloneVisitor *qcv = to_qcv(v);
 109
 110     assert(qcv->depth);
 111     /*
 112      * Pointer was already cloned by g_memdup; create fresh copy.
 113      * Note that as long as qobject-output-visitor accepts NULL instead of
 114      * "", then we must do likewise. However, we want to obey the
 115      * input visitor semantics of never producing NULL when the empty
 116      * string is intended.
 117      */
 118     *obj = g_strdup(*obj ?: "");
 119 }
 120
 121 static void qapi_clone_type_number(Visitor *v, const char *name, double *obj,
 122                                     Error **errp)
 123 {
 124     QapiCloneVisitor *qcv = to_qcv(v);
 125
 126     assert(qcv->depth);
 127     /* Value was already cloned by g_memdup() */
 128 }
 129
 130 static void qapi_clone_type_null(Visitor *v, const char *name, QNull **obj,
 131                                  Error **errp)
 132 {
 133     QapiCloneVisitor *qcv = to_qcv(v);
 134
 135     assert(qcv->depth);
 136     *obj = qnull();
 137 }
 138
 139 static void qapi_clone_free(Visitor *v)
 140 {
 141     g_free(v);
 142 }
 143
 144 static Visitor *qapi_clone_visitor_new(void)
 145 {
 146     QapiCloneVisitor *v;
 147
 148     v = g_malloc0(sizeof(*v));
 149
 150     v->visitor.type = VISITOR_CLONE;
 151     v->visitor.start_struct = qapi_clone_start_struct;
 152     v->visitor.end_struct = qapi_clone_end;
 153     v->visitor.start_list = qapi_clone_start_list;
 154     v->visitor.next_list = qapi_clone_next_list;
 155     v->visitor.end_list = qapi_clone_end;
 156     v->visitor.start_alternate = qapi_clone_start_alternate;
 157     v->visitor.end_alternate = qapi_clone_end;
 158     v->visitor.type_int64 = qapi_clone_type_int64;
 159     v->visitor.type_uint64 = qapi_clone_type_uint64;
 160     v->visitor.type_bool = qapi_clone_type_bool;
 161     v->visitor.type_str = qapi_clone_type_str;
 162     v->visitor.type_number = qapi_clone_type_number;
 163     v->visitor.type_null = qapi_clone_type_null;
 164     v->visitor.free = qapi_clone_free;
 165
 166     return &v->visitor;
 167 }
 168
 169 void *qapi_clone(const void *src, void (*visit_type)(Visitor *, const char *,
 170                                                      void **, Error **))
 171 {
 172     Visitor *v;
 173     void *dst = (void *) src; /* Cast away const */
 174
 175     if (!src) {
 176         return NULL;
 177     }
 178
 179     v = qapi_clone_visitor_new();
 180     visit_type(v, NULL, &dst, &error_abort);
 181     visit_free(v);
 182     return dst;
 183 }
 184
 185 void qapi_clone_members(void *dst, const void *src, size_t sz,
 186                         void (*visit_type_members)(Visitor *, void *,
 187                                                    Error **))
 188 {
 189     Visitor *v;
 190
 191     v = qapi_clone_visitor_new();
 192     memcpy(dst, src, sz);
 193     to_qcv(v)->depth++;
 194     visit_type_members(v, dst, &error_abort);
 195     visit_free(v);
 196 }