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 #include "qapi/qmp/qnull.h"
  16
  17 struct QapiCloneVisitor {
  18     Visitor visitor;
  19     size_t depth;
  20 };
  21
  22 static QapiCloneVisitor *to_qcv(Visitor *v)
  23 {
  24     return container_of(v, QapiCloneVisitor, visitor);
  25 }
  26
  27 static void qapi_clone_start_struct(Visitor *v, const char *name, void **obj,
  28                                     size_t size, Error **errp)
  29 {
  30     QapiCloneVisitor *qcv = to_qcv(v);
  31
  32     if (!obj) {
  33         assert(qcv->depth);
  34         /* Only possible when visiting an alternate's object
  35          * branch. Nothing further to do here, since the earlier
  36          * visit_start_alternate() already copied memory. */
  37         return;
  38     }
  39
  40     *obj = g_memdup(*obj, size);
  41     qcv->depth++;
  42 }
  43
  44 static void qapi_clone_end(Visitor *v, void **obj)
  45 {
  46     QapiCloneVisitor *qcv = to_qcv(v);
  47
  48     assert(qcv->depth);
  49     if (obj) {
  50         qcv->depth--;
  51     }
  52 }
  53
  54 static void qapi_clone_start_list(Visitor *v, const char *name,
  55                                   GenericList **listp, size_t size,
  56                                   Error **errp)
  57 {
  58     qapi_clone_start_struct(v, name, (void **)listp, size, errp);
  59 }
  60
  61 static GenericList *qapi_clone_next_list(Visitor *v, GenericList *tail,
  62                                          size_t size)
  63 {
  64     QapiCloneVisitor *qcv = to_qcv(v);
  65
  66     assert(qcv->depth);
  67     /* Unshare the tail of the list cloned by g_memdup() */
  68     tail->next = g_memdup(tail->next, size);
  69     return tail->next;
  70 }
  71
  72 static void qapi_clone_start_alternate(Visitor *v, const char *name,
  73                                        GenericAlternate **obj, size_t size,
  74                                        Error **errp)
  75 {
  76     qapi_clone_start_struct(v, name, (void **)obj, size, errp);
  77 }
  78
  79 static void qapi_clone_type_int64(Visitor *v, const char *name, int64_t *obj,
  80                                    Error **errp)
  81 {
  82     QapiCloneVisitor *qcv = to_qcv(v);
  83
  84     assert(qcv->depth);
  85     /* Value was already cloned by g_memdup() */
  86 }
  87
  88 static void qapi_clone_type_uint64(Visitor *v, const char *name,
  89                                     uint64_t *obj, Error **errp)
  90 {
  91     QapiCloneVisitor *qcv = to_qcv(v);
  92
  93     assert(qcv->depth);
  94     /* Value was already cloned by g_memdup() */
  95 }
  96
  97 static void qapi_clone_type_bool(Visitor *v, const char *name, bool *obj,
  98                                   Error **errp)
  99 {
 100     QapiCloneVisitor *qcv = to_qcv(v);
 101
 102     assert(qcv->depth);
 103     /* Value was already cloned by g_memdup() */
 104 }
 105
 106 static void qapi_clone_type_str(Visitor *v, const char *name, char **obj,
 107                                  Error **errp)
 108 {
 109     QapiCloneVisitor *qcv = to_qcv(v);
 110
 111     assert(qcv->depth);
 112     /*
 113      * Pointer was already cloned by g_memdup; create fresh copy.
 114      * Note that as long as qobject-output-visitor accepts NULL instead of
 115      * "", then we must do likewise. However, we want to obey the
 116      * input visitor semantics of never producing NULL when the empty
 117      * string is intended.
 118      */
 119     *obj = g_strdup(*obj ?: "");
 120 }
 121
 122 static void qapi_clone_type_number(Visitor *v, const char *name, double *obj,
 123                                     Error **errp)
 124 {
 125     QapiCloneVisitor *qcv = to_qcv(v);
 126
 127     assert(qcv->depth);
 128     /* Value was already cloned by g_memdup() */
 129 }
 130
 131 static void qapi_clone_type_null(Visitor *v, const char *name, QNull **obj,
 132                                  Error **errp)
 133 {
 134     QapiCloneVisitor *qcv = to_qcv(v);
 135
 136     assert(qcv->depth);
 137     *obj = qnull();
 138 }
 139
 140 static void qapi_clone_free(Visitor *v)
 141 {
 142     g_free(v);
 143 }
 144
 145 static Visitor *qapi_clone_visitor_new(void)
 146 {
 147     QapiCloneVisitor *v;
 148
 149     v = g_malloc0(sizeof(*v));
 150
 151     v->visitor.type = VISITOR_CLONE;
 152     v->visitor.start_struct = qapi_clone_start_struct;
 153     v->visitor.end_struct = qapi_clone_end;
 154     v->visitor.start_list = qapi_clone_start_list;
 155     v->visitor.next_list = qapi_clone_next_list;
 156     v->visitor.end_list = qapi_clone_end;
 157     v->visitor.start_alternate = qapi_clone_start_alternate;
 158     v->visitor.end_alternate = qapi_clone_end;
 159     v->visitor.type_int64 = qapi_clone_type_int64;
 160     v->visitor.type_uint64 = qapi_clone_type_uint64;
 161     v->visitor.type_bool = qapi_clone_type_bool;
 162     v->visitor.type_str = qapi_clone_type_str;
 163     v->visitor.type_number = qapi_clone_type_number;
 164     v->visitor.type_null = qapi_clone_type_null;
 165     v->visitor.free = qapi_clone_free;
 166
 167     return &v->visitor;
 168 }
 169
 170 void *qapi_clone(const void *src, void (*visit_type)(Visitor *, const char *,
 171                                                      void **, Error **))
 172 {
 173     Visitor *v;
 174     void *dst = (void *) src; /* Cast away const */
 175
 176     if (!src) {
 177         return NULL;
 178     }
 179
 180     v = qapi_clone_visitor_new();
 181     visit_type(v, NULL, &dst, &error_abort);
 182     visit_free(v);
 183     return dst;
 184 }
 185
 186 void qapi_clone_members(void *dst, const void *src, size_t sz,
 187                         void (*visit_type_members)(Visitor *, void *,
 188                                                    Error **))
 189 {
 190     Visitor *v;
 191
 192     v = qapi_clone_visitor_new();
 193     memcpy(dst, src, sz);
 194     to_qcv(v)->depth++;
 195     visit_type_members(v, dst, &error_abort);
 196     visit_free(v);
 197 }