qapi/string-output-visitor.c

   1 /*
   2  * String printing Visitor
   3  *
   4  * Copyright Red Hat, Inc. 2012-2016
   5  *
   6  * Author: Paolo Bonzini <pbonzini@redhat.com>
   7  *
   8  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
   9  * See the COPYING.LIB file in the top-level directory.
  10  *
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qemu-common.h"
  15 #include "qapi/string-output-visitor.h"
  16 #include "qapi/visitor-impl.h"
  17 #include "qemu/host-utils.h"
  18 #include <math.h>
  19 #include "qemu/range.h"
  20
  21 enum ListMode {
  22     LM_NONE,             /* not traversing a list of repeated options */
  23     LM_STARTED,          /* next_list() ready to be called */
  24
  25     LM_IN_PROGRESS,      /* next_list() has been called.
  26                           *
  27                           * Generating the next list link will consume the most
  28                           * recently parsed QemuOpt instance of the repeated
  29                           * option.
  30                           *
  31                           * Parsing a value into the list link will examine the
  32                           * next QemuOpt instance of the repeated option, and
  33                           * possibly enter LM_SIGNED_INTERVAL or
  34                           * LM_UNSIGNED_INTERVAL.
  35                           */
  36
  37     LM_SIGNED_INTERVAL,  /* next_list() has been called.
  38                           *
  39                           * Generating the next list link will consume the most
  40                           * recently stored element from the signed interval,
  41                           * parsed from the most recent QemuOpt instance of the
  42                           * repeated option. This may consume QemuOpt itself
  43                           * and return to LM_IN_PROGRESS.
  44                           *
  45                           * Parsing a value into the list link will store the
  46                           * next element of the signed interval.
  47                           */
  48
  49     LM_UNSIGNED_INTERVAL,/* Same as above, only for an unsigned interval. */
  50
  51     LM_END,              /* next_list() called, about to see last element. */
  52 };
  53
  54 typedef enum ListMode ListMode;
  55
  56 struct StringOutputVisitor
  57 {
  58     Visitor visitor;
  59     bool human;
  60     GString *string;
  61     char **result;
  62     ListMode list_mode;
  63     union {
  64         int64_t s;
  65         uint64_t u;
  66     } range_start, range_end;
  67     GList *ranges;
  68     void *list; /* Only needed for sanity checking the caller */
  69 };
  70
  71 static StringOutputVisitor *to_sov(Visitor *v)
  72 {
  73     return container_of(v, StringOutputVisitor, visitor);
  74 }
  75
  76 static void string_output_set(StringOutputVisitor *sov, char *string)
  77 {
  78     if (sov->string) {
  79         g_string_free(sov->string, true);
  80     }
  81     sov->string = g_string_new(string);
  82     g_free(string);
  83 }
  84
  85 static void string_output_append(StringOutputVisitor *sov, int64_t a)
  86 {
  87     Range *r = g_malloc0(sizeof(*r));
  88
  89     range_set_bounds(r, a, a);
  90     sov->ranges = range_list_insert(sov->ranges, r);
  91 }
  92
  93 static void string_output_append_range(StringOutputVisitor *sov,
  94                                        int64_t s, int64_t e)
  95 {
  96     Range *r = g_malloc0(sizeof(*r));
  97
  98     range_set_bounds(r, s, e);
  99     sov->ranges = range_list_insert(sov->ranges, r);
 100 }
 101
 102 static void format_string(StringOutputVisitor *sov, Range *r, bool next,
 103                           bool human)
 104 {
 105     if (range_lob(r) != range_upb(r)) {
 106         if (human) {
 107             g_string_append_printf(sov->string, "0x%" PRIx64 "-0x%" PRIx64,
 108                                    range_lob(r), range_upb(r));
 109
 110         } else {
 111             g_string_append_printf(sov->string, "%" PRId64 "-%" PRId64,
 112                                    range_lob(r), range_upb(r));
 113         }
 114     } else {
 115         if (human) {
 116             g_string_append_printf(sov->string, "0x%" PRIx64, range_lob(r));
 117         } else {
 118             g_string_append_printf(sov->string, "%" PRId64, range_lob(r));
 119         }
 120     }
 121     if (next) {
 122         g_string_append(sov->string, ",");
 123     }
 124 }
 125
 126 static void print_type_int64(Visitor *v, const char *name, int64_t *obj,
 127                              Error **errp)
 128 {
 129     StringOutputVisitor *sov = to_sov(v);
 130     GList *l;
 131
 132     switch (sov->list_mode) {
 133     case LM_NONE:
 134         string_output_append(sov, *obj);
 135         break;
 136
 137     case LM_STARTED:
 138         sov->range_start.s = *obj;
 139         sov->range_end.s = *obj;
 140         sov->list_mode = LM_IN_PROGRESS;
 141         return;
 142
 143     case LM_IN_PROGRESS:
 144         if (sov->range_end.s + 1 == *obj) {
 145             sov->range_end.s++;
 146         } else {
 147             if (sov->range_start.s == sov->range_end.s) {
 148                 string_output_append(sov, sov->range_end.s);
 149             } else {
 150                 assert(sov->range_start.s < sov->range_end.s);
 151                 string_output_append_range(sov, sov->range_start.s,
 152                                            sov->range_end.s);
 153             }
 154
 155             sov->range_start.s = *obj;
 156             sov->range_end.s = *obj;
 157         }
 158         return;
 159
 160     case LM_END:
 161         if (sov->range_end.s + 1 == *obj) {
 162             sov->range_end.s++;
 163             assert(sov->range_start.s < sov->range_end.s);
 164             string_output_append_range(sov, sov->range_start.s,
 165                                        sov->range_end.s);
 166         } else {
 167             if (sov->range_start.s == sov->range_end.s) {
 168                 string_output_append(sov, sov->range_end.s);
 169             } else {
 170                 assert(sov->range_start.s < sov->range_end.s);
 171
 172                 string_output_append_range(sov, sov->range_start.s,
 173                                            sov->range_end.s);
 174             }
 175             string_output_append(sov, *obj);
 176         }
 177         break;
 178
 179     default:
 180         abort();
 181     }
 182
 183     l = sov->ranges;
 184     while (l) {
 185         Range *r = l->data;
 186         format_string(sov, r, l->next != NULL, false);
 187         l = l->next;
 188     }
 189
 190     if (sov->human) {
 191         l = sov->ranges;
 192         g_string_append(sov->string, " (");
 193         while (l) {
 194             Range *r = l->data;
 195             format_string(sov, r, l->next != NULL, true);
 196             l = l->next;
 197         }
 198         g_string_append(sov->string, ")");
 199     }
 200 }
 201
 202 static void print_type_uint64(Visitor *v, const char *name, uint64_t *obj,
 203                              Error **errp)
 204 {
 205     /* FIXME: print_type_int64 mishandles values over INT64_MAX */
 206     int64_t i = *obj;
 207     print_type_int64(v, name, &i, errp);
 208 }
 209
 210 static void print_type_size(Visitor *v, const char *name, uint64_t *obj,
 211                             Error **errp)
 212 {
 213     StringOutputVisitor *sov = to_sov(v);
 214     static const char suffixes[] = { 'B', 'K', 'M', 'G', 'T', 'P', 'E' };
 215     uint64_t div, val;
 216     char *out;
 217     int i;
 218
 219     if (!sov->human) {
 220         out = g_strdup_printf("%"PRIu64, *obj);
 221         string_output_set(sov, out);
 222         return;
 223     }
 224
 225     val = *obj;
 226
 227     /* The exponent (returned in i) minus one gives us
 228      * floor(log2(val * 1024 / 1000).  The correction makes us
 229      * switch to the higher power when the integer part is >= 1000.
 230      */
 231     frexp(val / (1000.0 / 1024.0), &i);
 232     i = (i - 1) / 10;
 233     assert(i < ARRAY_SIZE(suffixes));
 234     div = 1ULL << (i * 10);
 235
 236     out = g_strdup_printf("%"PRIu64" (%0.3g %c%s)", val,
 237                           (double)val/div, suffixes[i], i ? "iB" : "");
 238     string_output_set(sov, out);
 239 }
 240
 241 static void print_type_bool(Visitor *v, const char *name, bool *obj,
 242                             Error **errp)
 243 {
 244     StringOutputVisitor *sov = to_sov(v);
 245     string_output_set(sov, g_strdup(*obj ? "true" : "false"));
 246 }
 247
 248 static void print_type_str(Visitor *v, const char *name, char **obj,
 249                            Error **errp)
 250 {
 251     StringOutputVisitor *sov = to_sov(v);
 252     char *out;
 253
 254     if (sov->human) {
 255         out = *obj ? g_strdup_printf("\"%s\"", *obj) : g_strdup("<null>");
 256     } else {
 257         out = g_strdup(*obj ? *obj : "");
 258     }
 259     string_output_set(sov, out);
 260 }
 261
 262 static void print_type_number(Visitor *v, const char *name, double *obj,
 263                               Error **errp)
 264 {
 265     StringOutputVisitor *sov = to_sov(v);
 266     string_output_set(sov, g_strdup_printf("%f", *obj));
 267 }
 268
 269 static void
 270 start_list(Visitor *v, const char *name, GenericList **list, size_t size,
 271            Error **errp)
 272 {
 273     StringOutputVisitor *sov = to_sov(v);
 274
 275     /* we can't traverse a list in a list */
 276     assert(sov->list_mode == LM_NONE);
 277     /* We don't support visits without a list */
 278     assert(list);
 279     sov->list = list;
 280     /* List handling is only needed if there are at least two elements */
 281     if (*list && (*list)->next) {
 282         sov->list_mode = LM_STARTED;
 283     }
 284 }
 285
 286 static GenericList *next_list(Visitor *v, GenericList *tail, size_t size)
 287 {
 288     StringOutputVisitor *sov = to_sov(v);
 289     GenericList *ret = tail->next;
 290
 291     if (ret && !ret->next) {
 292         sov->list_mode = LM_END;
 293     }
 294     return ret;
 295 }
 296
 297 static void end_list(Visitor *v, void **obj)
 298 {
 299     StringOutputVisitor *sov = to_sov(v);
 300
 301     assert(sov->list == obj);
 302     assert(sov->list_mode == LM_STARTED ||
 303            sov->list_mode == LM_END ||
 304            sov->list_mode == LM_NONE ||
 305            sov->list_mode == LM_IN_PROGRESS);
 306     sov->list_mode = LM_NONE;
 307 }
 308
 309 static void string_output_complete(Visitor *v, void *opaque)
 310 {
 311     StringOutputVisitor *sov = to_sov(v);
 312
 313     assert(opaque == sov->result);
 314     *sov->result = g_string_free(sov->string, false);
 315     sov->string = NULL;
 316 }
 317
 318 static void free_range(void *range, void *dummy)
 319 {
 320     g_free(range);
 321 }
 322
 323 static void string_output_free(Visitor *v)
 324 {
 325     StringOutputVisitor *sov = to_sov(v);
 326
 327     if (sov->string) {
 328         g_string_free(sov->string, true);
 329     }
 330
 331     g_list_foreach(sov->ranges, free_range, NULL);
 332     g_list_free(sov->ranges);
 333     g_free(sov);
 334 }
 335
 336 Visitor *string_output_visitor_new(bool human, char **result)
 337 {
 338     StringOutputVisitor *v;
 339
 340     v = g_malloc0(sizeof(*v));
 341
 342     v->string = g_string_new(NULL);
 343     v->human = human;
 344     v->result = result;
 345     *result = NULL;
 346
 347     v->visitor.type = VISITOR_OUTPUT;
 348     v->visitor.type_int64 = print_type_int64;
 349     v->visitor.type_uint64 = print_type_uint64;
 350     v->visitor.type_size = print_type_size;
 351     v->visitor.type_bool = print_type_bool;
 352     v->visitor.type_str = print_type_str;
 353     v->visitor.type_number = print_type_number;
 354     v->visitor.start_list = start_list;
 355     v->visitor.next_list = next_list;
 356     v->visitor.end_list = end_list;
 357     v->visitor.complete = string_output_complete;
 358     v->visitor.free = string_output_free;
 359
 360     return &v->visitor;
 361 }