2 * Copyright © 2007, 2008 Ryan Lortie
3 * Copyright © 2010 Codethink Limited
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 02111-1307, USA.
20 * Author: Ryan Lortie <desrt@desrt.ca>
26 #include "gvariant-serialiser.h"
28 #include <glib/gtestutils.h>
29 #include <glib/gstrfuncs.h>
30 #include <glib/gtypes.h>
38 * After this prologue section, this file has roughly 2 parts.
40 * The first part is split up into sections according to various
41 * container types. Maybe, Array, Tuple, Variant. The Maybe and Array
42 * sections are subdivided for element types being fixed or
43 * variable-sized types.
45 * Each section documents the format of that particular type of
46 * container and implements 5 functions for dealing with it:
49 * - determines (according to serialised data) how many child values
50 * are inside a particular container value.
53 * - gets the type of and the serialised data corresponding to a
54 * given child value within the container value.
57 * - determines how much space would be required to serialise a
58 * container of this type, containing the given children so that
59 * buffers can be preallocated before serialising.
62 * - write the serialised data for a container of this type,
63 * containing the given children, to a buffer.
66 * - check the given data to ensure that it is in normal form. For a
67 * given set of child values, there is exactly one normal form for
68 * the serialised data of a container. Other forms are possible
69 * while maintaining the same children (for example, by inserting
70 * something other than zero bytes as padding) but only one form is
73 * The second part contains the main entry point for each of the above 5
74 * functions and logic to dispatch it to the handler for the appropriate
75 * container type code.
77 * The second part also contains a routine to byteswap serialised
78 * values. This code makes use of the n_children() and get_child()
79 * functions above to do its work so no extra support is needed on a
80 * per-container-type basis.
82 * There is also additional code for checking for normal form. All
83 * numeric types are always in normal form since the full range of
84 * values is permitted (eg: 0 to 255 is a valid byte). Special checks
85 * need to be performed for booleans (only 0 or 1 allowed), strings
86 * (properly nul-terminated) and object paths and signature strings
87 * (meeting the DBus specification requirements).
92 * @type_info: the #GVariantTypeInfo of this value
93 * @data: the serialised data of this value, or %NULL
94 * @size: the size of this value
96 * A structure representing a GVariant in serialised form. This
97 * structure is used with #GVariantSerialisedFiller functions and as the
98 * primary interface to the serialiser. See #GVariantSerialisedFiller
99 * for a description of its use there.
101 * When used with the serialiser API functions, the following invariants
102 * apply to all #GVariantTypeSerialised structures passed to and
103 * returned from the serialiser.
105 * @type_info must be non-%NULL.
107 * @data must be properly aligned for the type described by @type_info.
109 * If @type_info describes a fixed-sized type then @size must always be
110 * equal to the fixed size of that type.
112 * For fixed-sized types (and only fixed-sized types), @data may be
113 * %NULL even if @size is non-zero. This happens when a framing error
114 * occurs while attempting to extract a fixed-sized value out of a
115 * variable-sized container. There is no data to return for the
116 * fixed-sized type, yet @size must be non-zero. The effect of this
117 * combination should be as if @data were a pointer to an
118 * appropriately-sized zero-filled region.
122 * g_variant_serialised_check:
123 * @serialised: a #GVariantSerialised struct
125 * Checks @serialised for validity according to the invariants described
129 g_variant_serialised_check (GVariantSerialised serialised)
134 g_assert (serialised.type_info != NULL);
135 g_variant_type_info_query (serialised.type_info, &alignment, &fixed_size);
138 g_assert_cmpint (serialised.size, ==, fixed_size);
140 g_assert (serialised.size == 0 || serialised.data != NULL);
142 /* Depending on the native alignment requirements of the machine, the
143 * compiler will insert either 3 or 7 padding bytes after the char.
144 * This will result in the sizeof() the struct being 12 or 16.
145 * Subtract 9 to get 3 or 7 which is a nice bitmask to apply to get
146 * the alignment bits that we "care about" being zero: in the
147 * 4-aligned case, we care about 2 bits, and in the 8-aligned case, we
150 alignment &= sizeof (struct {
160 g_assert_cmpint (alignment & (gsize) serialised.data, ==, 0);
164 * GVariantSerialisedFiller:
165 * @serialised: a #GVariantSerialised instance to fill
166 * @data: data from the children array
168 * This function is called back from g_variant_serialiser_needed_size()
169 * and g_variant_serialiser_serialise(). It fills in missing details
170 * from a partially-complete #GVariantSerialised.
172 * The @data parameter passed back to the function is one of the items
173 * that was passed to the serialiser in the @children array. It
174 * represents a single child item of the container that is being
175 * serialised. The information filled in to @serialised is the
176 * information for this child.
178 * If the @type_info field of @serialised is %NULL then the callback
179 * function must set it to the type information corresponding to the
180 * type of the child. No reference should be added. If it is non-%NULL
181 * then the callback should assert that it is equal to the actual type
184 * If the @size field is zero then the callback must fill it in with the
185 * required amount of space to store the serialised form of the child.
186 * If it is non-zero then the callback should assert that it is equal to
187 * the needed size of the child.
189 * If @data is non-%NULL then it points to a space that is properly
190 * aligned for and large enough to store the serialised data of the
191 * child. The callback must store the serialised form of the child at
194 * If the child value is another container then the callback will likely
195 * recurse back into the serialiser by calling
196 * g_variant_serialiser_needed_size() to determine @size and
197 * g_variant_serialiser_serialise() to write to @data.
200 /* PART 1: Container types {{{1
202 * This section contains the serialiser implementation functions for
203 * each container type.
208 * Maybe types are handled depending on if the element type of the maybe
209 * type is a fixed-sized or variable-sized type. Although all maybe
210 * types themselves are variable-sized types, herein, a maybe value with
211 * a fixed-sized element type is called a "fixed-sized maybe" for
212 * convenience and a maybe value with a variable-sized element type is
213 * called a "variable-sized maybe".
216 /* Fixed-sized Maybe {{{3
218 * The size of a maybe value with a fixed-sized element type is either 0
219 * or equal to the fixed size of its element type. The case where the
220 * size of the maybe value is zero corresponds to the "Nothing" case and
221 * the case where the size of the maybe value is equal to the fixed size
222 * of the element type corresponds to the "Just" case; in that case, the
223 * serialised data of the child value forms the entire serialised data
224 * of the maybe value.
226 * In the event that a fixed-sized maybe value is presented with a size
227 * that is not equal to the fixed size of the element type then the
228 * value must be taken to be "Nothing".
232 gvs_fixed_sized_maybe_n_children (GVariantSerialised value)
234 gsize element_fixed_size;
236 g_variant_type_info_query_element (value.type_info, NULL,
237 &element_fixed_size);
239 return (element_fixed_size == value.size) ? 1 : 0;
242 static GVariantSerialised
243 gvs_fixed_sized_maybe_get_child (GVariantSerialised value,
246 /* the child has the same bounds as the
247 * container, so just update the type.
249 value.type_info = g_variant_type_info_element (value.type_info);
250 g_variant_type_info_ref (value.type_info);
256 gvs_fixed_sized_maybe_needed_size (GVariantTypeInfo *type_info,
257 GVariantSerialisedFiller gvs_filler,
258 const gpointer *children,
263 gsize element_fixed_size;
265 g_variant_type_info_query_element (type_info, NULL,
266 &element_fixed_size);
268 return element_fixed_size;
275 gvs_fixed_sized_maybe_serialise (GVariantSerialised value,
276 GVariantSerialisedFiller gvs_filler,
277 const gpointer *children,
282 GVariantSerialised child = { NULL, value.data, value.size };
284 gvs_filler (&child, children[0]);
289 gvs_fixed_sized_maybe_is_normal (GVariantSerialised value)
293 gsize element_fixed_size;
295 g_variant_type_info_query_element (value.type_info,
296 NULL, &element_fixed_size);
298 if (value.size != element_fixed_size)
301 /* proper element size: "Just". recurse to the child. */
302 value.type_info = g_variant_type_info_element (value.type_info);
304 return g_variant_serialised_is_normal (value);
307 /* size of 0: "Nothing" */
311 /* Variable-sized Maybe
313 * The size of a maybe value with a variable-sized element type is
314 * either 0 or strictly greater than 0. The case where the size of the
315 * maybe value is zero corresponds to the "Nothing" case and the case
316 * where the size of the maybe value is greater than zero corresponds to
317 * the "Just" case; in that case, the serialised data of the child value
318 * forms the first part of the serialised data of the maybe value and is
319 * followed by a single zero byte. This zero byte is always appended,
320 * regardless of any zero bytes that may already be at the end of the
321 * serialised ata of the child value.
325 gvs_variable_sized_maybe_n_children (GVariantSerialised value)
327 return (value.size > 0) ? 1 : 0;
330 static GVariantSerialised
331 gvs_variable_sized_maybe_get_child (GVariantSerialised value,
334 /* remove the padding byte and update the type. */
335 value.type_info = g_variant_type_info_element (value.type_info);
336 g_variant_type_info_ref (value.type_info);
339 /* if it's zero-sized then it may as well be NULL */
347 gvs_variable_sized_maybe_needed_size (GVariantTypeInfo *type_info,
348 GVariantSerialisedFiller gvs_filler,
349 const gpointer *children,
354 GVariantSerialised child = { 0, };
356 gvs_filler (&child, children[0]);
358 return child.size + 1;
365 gvs_variable_sized_maybe_serialise (GVariantSerialised value,
366 GVariantSerialisedFiller gvs_filler,
367 const gpointer *children,
372 GVariantSerialised child = { NULL, value.data, value.size - 1 };
374 /* write the data for the child. */
375 gvs_filler (&child, children[0]);
376 value.data[child.size] = '\0';
381 gvs_variable_sized_maybe_is_normal (GVariantSerialised value)
386 if (value.data[value.size - 1] != '\0')
389 value.type_info = g_variant_type_info_element (value.type_info);
392 return g_variant_serialised_is_normal (value);
397 * Just as with maybe types, array types are handled depending on if the
398 * element type of the array type is a fixed-sized or variable-sized
399 * type. Similar to maybe types, for convenience, an array value with a
400 * fixed-sized element type is called a "fixed-sized array" and an array
401 * value with a variable-sized element type is called a "variable sized
405 /* Fixed-sized Array {{{3
407 * For fixed sized arrays, the serialised data is simply a concatenation
408 * of the serialised data of each element, in order. Since fixed-sized
409 * values always have a fixed size that is a multiple of their alignment
410 * requirement no extra padding is required.
412 * In the event that a fixed-sized array is presented with a size that
413 * is not an integer multiple of the element size then the value of the
414 * array must be taken as being empty.
418 gvs_fixed_sized_array_n_children (GVariantSerialised value)
420 gsize element_fixed_size;
422 g_variant_type_info_query_element (value.type_info, NULL,
423 &element_fixed_size);
425 if (value.size % element_fixed_size == 0)
426 return value.size / element_fixed_size;
431 static GVariantSerialised
432 gvs_fixed_sized_array_get_child (GVariantSerialised value,
435 GVariantSerialised child = { 0, };
437 child.type_info = g_variant_type_info_element (value.type_info);
438 g_variant_type_info_query (child.type_info, NULL, &child.size);
439 child.data = value.data + (child.size * index_);
440 g_variant_type_info_ref (child.type_info);
446 gvs_fixed_sized_array_needed_size (GVariantTypeInfo *type_info,
447 GVariantSerialisedFiller gvs_filler,
448 const gpointer *children,
451 gsize element_fixed_size;
453 g_variant_type_info_query_element (type_info, NULL, &element_fixed_size);
455 return element_fixed_size * n_children;
459 gvs_fixed_sized_array_serialise (GVariantSerialised value,
460 GVariantSerialisedFiller gvs_filler,
461 const gpointer *children,
464 GVariantSerialised child = { 0, };
467 child.type_info = g_variant_type_info_element (value.type_info);
468 g_variant_type_info_query (child.type_info, NULL, &child.size);
469 child.data = value.data;
471 for (i = 0; i < n_children; i++)
473 gvs_filler (&child, children[i]);
474 child.data += child.size;
479 gvs_fixed_sized_array_is_normal (GVariantSerialised value)
481 GVariantSerialised child = { 0, };
483 child.type_info = g_variant_type_info_element (value.type_info);
484 g_variant_type_info_query (child.type_info, NULL, &child.size);
486 if (value.size % child.size != 0)
489 for (child.data = value.data;
490 child.data < value.data + value.size;
491 child.data += child.size)
493 if (!g_variant_serialised_is_normal (child))
500 /* Variable-sized Array {{{3
502 * Variable sized arrays, containing variable-sized elements, must be
503 * able to determine the boundaries between the elements. The items
504 * cannot simply be concatenated. Additionally, we are faced with the
505 * fact that non-fixed-sized values do not neccessarily have a size that
506 * is a multiple of their alignment requirement, so we may need to
507 * insert zero-filled padding.
509 * While it is possible to find the start of an item by starting from
510 * the end of the item before it and padding for alignment, it is not
511 * generally possible to do the reverse operation. For this reason, we
512 * record the end point of each element in the array.
514 * GVariant works in terms of "offsets". An offset is a pointer to a
515 * boundary between two bytes. In 4 bytes of serialised data, there
516 * would be 5 possible offsets: one at the start ('0'), one between each
517 * pair of adjacent bytes ('1', '2', '3') and one at the end ('4').
519 * The numeric value of an offset is an unsigned integer given relative
520 * to the start of the serialised data of the array. Offsets are always
521 * stored in little endian byte order and are always only as big as they
522 * need to be. For example, in 255 bytes of serialised data, there are
523 * 256 offsets. All possibilities can be stored in an 8 bit unsigned
524 * integer. In 256 bytes of serialised data, however, there are 257
525 * possible offsets so 16 bit integers must be used. The size of an
526 * offset is always a power of 2.
528 * The offsets are stored at the end of the serialised data of the
529 * array. They are simply concatenated on without any particular
530 * alignment. The size of the offsets is included in the size of the
531 * serialised data for purposes of determining the size of the offsets.
532 * This presents a possibly ambiguity; in certain cases, a particular
533 * value of array could have two different serialised forms.
535 * Imagine an array containing a single string of 253 bytes in length
536 * (so, 254 bytes including the nul terminator). Now the offset must be
537 * written. If an 8 bit offset is written, it will bring the size of
538 * the array's serialised data to 255 -- which means that the use of an
539 * 8 bit offset was valid. If a 16 bit offset is used then the total
540 * size of the array will be 256 -- which means that the use of a 16 bit
541 * offset was valid. Although both of these will be accepted by the
542 * deserialiser, only the smaller of the two is considered to be in
543 * normal form and that is the one that the serialiser must produce.
547 gvs_read_unaligned_le (guchar *bytes,
552 guchar bytes[GLIB_SIZEOF_SIZE_T];
556 tmpvalue.integer = 0;
557 memcpy (&tmpvalue.bytes, bytes, size);
559 return GSIZE_FROM_LE (tmpvalue.integer);
563 gvs_write_unaligned_le (guchar *bytes,
569 guchar bytes[GLIB_SIZEOF_SIZE_T];
573 tmpvalue.integer = GSIZE_TO_LE (value);
574 memcpy (bytes, &tmpvalue.bytes, size);
578 gvs_get_offset_size (gsize size)
580 if (size > G_MAXUINT32)
583 else if (size > G_MAXUINT16)
586 else if (size > G_MAXUINT8)
596 gvs_calculate_total_size (gsize body_size,
599 if (body_size + 1 * offsets <= G_MAXUINT8)
600 return body_size + 1 * offsets;
602 if (body_size + 2 * offsets <= G_MAXUINT16)
603 return body_size + 2 * offsets;
605 if (body_size + 4 * offsets <= G_MAXUINT32)
606 return body_size + 4 * offsets;
608 return body_size + 8 * offsets;
612 gvs_variable_sized_array_n_children (GVariantSerialised value)
614 gsize offsets_array_size;
621 offset_size = gvs_get_offset_size (value.size);
623 last_end = gvs_read_unaligned_le (value.data + value.size -
624 offset_size, offset_size);
626 if (last_end > value.size)
629 offsets_array_size = value.size - last_end;
631 if (offsets_array_size % offset_size)
634 return offsets_array_size / offset_size;
637 static GVariantSerialised
638 gvs_variable_sized_array_get_child (GVariantSerialised value,
641 GVariantSerialised child = { 0, };
647 child.type_info = g_variant_type_info_element (value.type_info);
648 g_variant_type_info_ref (child.type_info);
650 offset_size = gvs_get_offset_size (value.size);
652 last_end = gvs_read_unaligned_le (value.data + value.size -
653 offset_size, offset_size);
659 start = gvs_read_unaligned_le (value.data + last_end +
660 (offset_size * (index_ - 1)),
663 g_variant_type_info_query (child.type_info, &alignment, NULL);
664 start += (-start) & alignment;
669 end = gvs_read_unaligned_le (value.data + last_end +
670 (offset_size * index_),
673 if (start < end && end <= value.size)
675 child.data = value.data + start;
676 child.size = end - start;
683 gvs_variable_sized_array_needed_size (GVariantTypeInfo *type_info,
684 GVariantSerialisedFiller gvs_filler,
685 const gpointer *children,
692 g_variant_type_info_query (type_info, &alignment, NULL);
695 for (i = 0; i < n_children; i++)
697 GVariantSerialised child = { 0, };
699 offset += (-offset) & alignment;
700 gvs_filler (&child, children[i]);
701 offset += child.size;
704 return gvs_calculate_total_size (offset, n_children);
708 gvs_variable_sized_array_serialise (GVariantSerialised value,
709 GVariantSerialisedFiller gvs_filler,
710 const gpointer *children,
719 g_variant_type_info_query (value.type_info, &alignment, NULL);
720 offset_size = gvs_get_offset_size (value.size);
723 offset_ptr = value.data + value.size - offset_size * n_children;
725 for (i = 0; i < n_children; i++)
727 GVariantSerialised child = { 0, };
729 while (offset & alignment)
730 value.data[offset++] = '\0';
732 child.data = value.data + offset;
733 gvs_filler (&child, children[i]);
734 offset += child.size;
736 gvs_write_unaligned_le (offset_ptr, offset, offset_size);
737 offset_ptr += offset_size;
742 gvs_variable_sized_array_is_normal (GVariantSerialised value)
744 GVariantSerialised child = { 0, };
745 gsize offsets_array_size;
746 guchar *offsets_array;
757 offset_size = gvs_get_offset_size (value.size);
758 last_end = gvs_read_unaligned_le (value.data + value.size -
759 offset_size, offset_size);
761 if (last_end > value.size)
764 offsets_array_size = value.size - last_end;
766 if (offsets_array_size % offset_size)
769 offsets_array = value.data + value.size - offsets_array_size;
770 length = offsets_array_size / offset_size;
775 child.type_info = g_variant_type_info_element (value.type_info);
776 g_variant_type_info_query (child.type_info, &alignment, NULL);
779 for (i = 0; i < length; i++)
783 this_end = gvs_read_unaligned_le (offsets_array + offset_size * i,
786 if (this_end < offset || this_end > last_end)
789 while (offset & alignment)
791 if (!(offset < this_end && value.data[offset] == '\0'))
796 child.data = value.data + offset;
797 child.size = this_end - offset;
802 if (!g_variant_serialised_is_normal (child))
808 g_assert (offset == last_end);
815 * Since tuples can contain a mix of variable- and fixed-sized items,
816 * they are, in terms of serialisation, a hybrid of variable-sized and
817 * fixed-sized arrays.
819 * Offsets are only stored for variable-sized items. Also, since the
820 * number of items in a tuple is known from its type, we are able to
821 * know exactly how many offsets to expect in the serialised data (and
822 * therefore how much space is taken up by the offset array). This
823 * means that we know where the end of the serialised data for the last
824 * item is -- we can just subtract the size of the offset array from the
825 * total size of the tuple. For this reason, the last item in the tuple
826 * doesn't need an offset stored.
828 * Tuple offsets are stored in reverse. This design choice allows
829 * iterator-based deserialisers to be more efficient.
831 * Most of the "heavy lifting" here is handled by the GVariantTypeInfo
832 * for the tuple. See the notes in gvarianttypeinfo.h.
836 gvs_tuple_n_children (GVariantSerialised value)
838 return g_variant_type_info_n_members (value.type_info);
841 static GVariantSerialised
842 gvs_tuple_get_child (GVariantSerialised value,
845 const GVariantMemberInfo *member_info;
846 GVariantSerialised child = { 0, };
850 member_info = g_variant_type_info_member_info (value.type_info, index_);
851 child.type_info = g_variant_type_info_ref (member_info->type_info);
852 offset_size = gvs_get_offset_size (value.size);
854 /* tuples are the only (potentially) fixed-sized containers, so the
855 * only ones that have to deal with the possibility of having %NULL
856 * data with a non-zero %size if errors occured elsewhere.
858 if G_UNLIKELY (value.data == NULL && value.size != 0)
860 g_variant_type_info_query (child.type_info, NULL, &child.size);
862 /* this can only happen in fixed-sized tuples,
863 * so the child must also be fixed sized.
865 g_assert (child.size != 0);
871 if (member_info->ending_type == G_VARIANT_MEMBER_ENDING_OFFSET)
873 if (offset_size * (member_info->i + 2) > value.size)
878 if (offset_size * (member_info->i + 1) > value.size)
880 /* if the child is fixed size, return its size.
881 * if child is not fixed-sized, return size = 0.
883 g_variant_type_info_query (child.type_info, NULL, &child.size);
889 if (member_info->i + 1)
890 start = gvs_read_unaligned_le (value.data + value.size -
891 offset_size * (member_info->i + 1),
896 start += member_info->a;
897 start &= member_info->b;
898 start |= member_info->c;
900 if (member_info->ending_type == G_VARIANT_MEMBER_ENDING_LAST)
901 end = value.size - offset_size * (member_info->i + 1);
903 else if (member_info->ending_type == G_VARIANT_MEMBER_ENDING_FIXED)
907 g_variant_type_info_query (child.type_info, NULL, &fixed_size);
908 end = start + fixed_size;
909 child.size = fixed_size;
912 else /* G_VARIANT_MEMEBER_ENDING_OFFSET */
913 end = gvs_read_unaligned_le (value.data + value.size -
914 offset_size * (member_info->i + 2),
917 if (start < end && end <= value.size)
919 child.data = value.data + start;
920 child.size = end - start;
927 gvs_tuple_needed_size (GVariantTypeInfo *type_info,
928 GVariantSerialisedFiller gvs_filler,
929 const gpointer *children,
932 const GVariantMemberInfo *member_info = NULL;
937 g_variant_type_info_query (type_info, NULL, &fixed_size);
944 for (i = 0; i < n_children; i++)
948 member_info = g_variant_type_info_member_info (type_info, i);
949 g_variant_type_info_query (member_info->type_info,
950 &alignment, &fixed_size);
951 offset += (-offset) & alignment;
954 offset += fixed_size;
957 GVariantSerialised child = { 0, };
959 gvs_filler (&child, children[i]);
960 offset += child.size;
964 return gvs_calculate_total_size (offset, member_info->i + 1);
968 gvs_tuple_serialise (GVariantSerialised value,
969 GVariantSerialisedFiller gvs_filler,
970 const gpointer *children,
977 offset_size = gvs_get_offset_size (value.size);
980 for (i = 0; i < n_children; i++)
982 const GVariantMemberInfo *member_info;
983 GVariantSerialised child = { 0, };
986 member_info = g_variant_type_info_member_info (value.type_info, i);
987 g_variant_type_info_query (member_info->type_info, &alignment, NULL);
989 while (offset & alignment)
990 value.data[offset++] = '\0';
992 child.data = value.data + offset;
993 gvs_filler (&child, children[i]);
994 offset += child.size;
996 if (member_info->ending_type == G_VARIANT_MEMBER_ENDING_OFFSET)
998 value.size -= offset_size;
999 gvs_write_unaligned_le (value.data + value.size,
1000 offset, offset_size);
1004 while (offset < value.size)
1005 value.data[offset++] = '\0';
1009 gvs_tuple_is_normal (GVariantSerialised value)
1017 offset_size = gvs_get_offset_size (value.size);
1018 length = g_variant_type_info_n_members (value.type_info);
1019 offset_ptr = value.size;
1022 for (i = 0; i < length; i++)
1024 const GVariantMemberInfo *member_info;
1025 GVariantSerialised child;
1030 member_info = g_variant_type_info_member_info (value.type_info, i);
1031 child.type_info = member_info->type_info;
1033 g_variant_type_info_query (child.type_info, &alignment, &fixed_size);
1035 while (offset & alignment)
1037 if (offset > value.size || value.data[offset] != '\0')
1042 child.data = value.data + offset;
1044 switch (member_info->ending_type)
1046 case G_VARIANT_MEMBER_ENDING_FIXED:
1047 end = offset + fixed_size;
1050 case G_VARIANT_MEMBER_ENDING_LAST:
1054 case G_VARIANT_MEMBER_ENDING_OFFSET:
1055 offset_ptr -= offset_size;
1057 if (offset_ptr < offset)
1060 end = gvs_read_unaligned_le (value.data + offset_ptr, offset_size);
1064 g_assert_not_reached ();
1067 if (end < offset || end > offset_ptr)
1070 child.size = end - offset;
1072 if (child.size == 0)
1075 if (!g_variant_serialised_is_normal (child))
1085 g_variant_type_info_query (value.type_info, &alignment, &fixed_size);
1089 g_assert (fixed_size == value.size);
1090 g_assert (offset_ptr == value.size);
1094 if (value.data[offset++] != '\0')
1099 while (offset & alignment)
1100 if (value.data[offset++] != '\0')
1104 g_assert (offset == value.size);
1108 return offset_ptr == offset;
1113 * Variants are stored by storing the serialised data of the child,
1114 * followed by a '\0' character, followed by the type string of the
1117 * In the case that a value is presented that contains no '\0'
1118 * character, or doesn't have a single well-formed definite type string
1119 * following that character, the variant must be taken as containing the
1124 gvs_variant_n_children (GVariantSerialised value)
1129 static inline GVariantSerialised
1130 gvs_variant_get_child (GVariantSerialised value,
1133 GVariantSerialised child = { 0, };
1135 /* NOTE: not O(1) and impossible for it to be... */
1138 /* find '\0' character */
1139 for (child.size = value.size - 1; child.size; child.size--)
1140 if (value.data[child.size] == '\0')
1143 /* ensure we didn't just hit the start of the string */
1144 if (value.data[child.size] == '\0')
1146 const gchar *type_string = (gchar *) &value.data[child.size + 1];
1147 const gchar *limit = (gchar *) &value.data[value.size];
1150 if (g_variant_type_string_scan (type_string, limit, &end) &&
1153 const GVariantType *type = (GVariantType *) type_string;
1155 if (g_variant_type_is_definite (type))
1159 child.type_info = g_variant_type_info_get (type);
1161 if (child.size != 0)
1162 /* only set to non-%NULL if size > 0 */
1163 child.data = value.data;
1165 g_variant_type_info_query (child.type_info,
1168 if (!fixed_size || fixed_size == child.size)
1171 g_variant_type_info_unref (child.type_info);
1177 child.type_info = g_variant_type_info_get (G_VARIANT_TYPE_UNIT);
1185 gvs_variant_needed_size (GVariantTypeInfo *type_info,
1186 GVariantSerialisedFiller gvs_filler,
1187 const gpointer *children,
1190 GVariantSerialised child = { 0, };
1191 const gchar *type_string;
1193 gvs_filler (&child, children[0]);
1194 type_string = g_variant_type_info_get_type_string (child.type_info);
1196 return child.size + 1 + strlen (type_string);
1200 gvs_variant_serialise (GVariantSerialised value,
1201 GVariantSerialisedFiller gvs_filler,
1202 const gpointer *children,
1205 GVariantSerialised child = { 0, };
1206 const gchar *type_string;
1208 child.data = value.data;
1210 gvs_filler (&child, children[0]);
1211 type_string = g_variant_type_info_get_type_string (child.type_info);
1212 value.data[child.size] = '\0';
1213 memcpy (value.data + child.size + 1, type_string, strlen (type_string));
1216 static inline gboolean
1217 gvs_variant_is_normal (GVariantSerialised value)
1219 GVariantSerialised child;
1222 child = gvs_variant_get_child (value, 0);
1224 normal = (child.data != NULL || child.size == 0) &&
1225 g_variant_serialised_is_normal (child);
1227 g_variant_type_info_unref (child.type_info);
1234 /* PART 2: Serialiser API {{{1
1236 * This is the implementation of the API of the serialiser as advertised
1237 * in gvariant-serialiser.h.
1240 /* Dispatch Utilities {{{2
1242 * These macros allow a given function (for example,
1243 * g_variant_serialiser_serialise) to be dispatched to the appropriate
1244 * type-specific function above (fixed/variable-sized maybe,
1245 * fixed/variable-sized array, tuple or variant).
1247 #define DISPATCH_FIXED(type_info, before, after) \
1251 g_variant_type_info_query_element (type_info, NULL, \
1256 before ## fixed_sized ## after \
1260 before ## variable_sized ## after \
1264 #define DISPATCH_CASES(type_info, before, after) \
1265 switch (g_variant_type_info_get_type_char (type_info)) \
1267 case G_VARIANT_TYPE_INFO_CHAR_MAYBE: \
1268 DISPATCH_FIXED (type_info, before, _maybe ## after) \
1270 case G_VARIANT_TYPE_INFO_CHAR_ARRAY: \
1271 DISPATCH_FIXED (type_info, before, _array ## after) \
1273 case G_VARIANT_TYPE_INFO_CHAR_DICT_ENTRY: \
1274 case G_VARIANT_TYPE_INFO_CHAR_TUPLE: \
1276 before ## tuple ## after \
1279 case G_VARIANT_TYPE_INFO_CHAR_VARIANT: \
1281 before ## variant ## after \
1285 /* Serialiser entry points {{{2
1287 * These are the functions that are called in order for the serialiser
1292 * g_variant_serialised_n_children:
1293 * @serialised: a #GVariantSerialised
1294 * @returns: the number of children
1296 * For serialised data that represents a container value (maybes,
1297 * tuples, arrays, variants), determine how many child items are inside
1301 g_variant_serialised_n_children (GVariantSerialised serialised)
1303 g_variant_serialised_check (serialised);
1305 DISPATCH_CASES (serialised.type_info,
1307 return gvs_/**/,/**/_n_children (serialised);
1310 g_assert_not_reached ();
1314 * g_variant_serialised_get_child:
1315 * @serialised: a #GVariantSerialised
1316 * @index_: the index of the child to fetch
1317 * @returns: a #GVariantSerialised for the child
1319 * Extracts a child from a serialised data representing a container
1322 * It is an error to call this function with an index out of bounds.
1324 * If the result .data == %NULL and .size > 0 then there has been an
1325 * error extracting the requested fixed-sized value. This number of
1326 * zero bytes needs to be allocated instead.
1328 * In the case that .data == %NULL and .size == 0 then a zero-sized
1329 * item of a variable-sized type is being returned.
1331 * .data is never non-%NULL if size is 0.
1334 g_variant_serialised_get_child (GVariantSerialised serialised,
1337 GVariantSerialised child;
1339 g_variant_serialised_check (serialised);
1341 if G_LIKELY (index_ < g_variant_serialised_n_children (serialised))
1343 DISPATCH_CASES (serialised.type_info,
1345 child = gvs_/**/,/**/_get_child (serialised, index_);
1346 g_assert (child.size || child.data == NULL);
1347 g_variant_serialised_check (child);
1351 g_assert_not_reached ();
1354 g_error ("Attempt to access item %"G_GSIZE_FORMAT
1355 " in a container with only %"G_GSIZE_FORMAT" items",
1356 index_, g_variant_serialised_n_children (serialised));
1360 * g_variant_serialiser_serialise:
1361 * @serialised: a #GVariantSerialised, properly set up
1362 * @gvs_filler: the filler function
1363 * @children: an array of child items
1364 * @n_children: the size of @children
1366 * Writes data in serialised form.
1368 * The type_info field of @serialised must be filled in to type info for
1369 * the type that we are serialising.
1371 * The size field of @serialised must be filled in with the value
1372 * returned by a previous call to g_variant_serialiser_needed_size().
1374 * The data field of @serialised must be a pointer to a properly-aligned
1375 * memory region large enough to serialise into (ie: at least as big as
1378 * This function is only resonsible for serialising the top-level
1379 * container. @gvs_filler is called on each child of the container in
1380 * order for all of the data of that child to be filled in.
1383 g_variant_serialiser_serialise (GVariantSerialised serialised,
1384 GVariantSerialisedFiller gvs_filler,
1385 const gpointer *children,
1388 g_variant_serialised_check (serialised);
1390 DISPATCH_CASES (serialised.type_info,
1392 gvs_/**/,/**/_serialise (serialised, gvs_filler,
1393 children, n_children);
1397 g_assert_not_reached ();
1401 * g_variant_serialiser_needed_size:
1402 * @type_info: the type to serialise for
1403 * @gvs_filler: the filler function
1404 * @children: an array of child items
1405 * @n_children: the size of @children
1407 * Determines how much memory would be needed to serialise this value.
1409 * This function is only resonsible for performing calculations for the
1410 * top-level container. @gvs_filler is called on each child of the
1411 * container in order to determine its size.
1414 g_variant_serialiser_needed_size (GVariantTypeInfo *type_info,
1415 GVariantSerialisedFiller gvs_filler,
1416 const gpointer *children,
1419 DISPATCH_CASES (type_info,
1421 return gvs_/**/,/**/_needed_size (type_info, gvs_filler,
1422 children, n_children);
1425 g_assert_not_reached ();
1428 /* Byteswapping {{{2 */
1431 * g_variant_serialised_byteswap:
1432 * @value: a #GVariantSerialised
1434 * Byte-swap serialised data. The result of this function is only
1435 * well-defined if the data is in normal form.
1438 g_variant_serialised_byteswap (GVariantSerialised serialised)
1443 g_variant_serialised_check (serialised);
1445 if (!serialised.data)
1448 /* the types we potentially need to byteswap are
1449 * exactly those with alignment requirements.
1451 g_variant_type_info_query (serialised.type_info, &alignment, &fixed_size);
1455 /* if fixed size and alignment are equal then we are down
1456 * to the base integer type and we should swap it. the
1457 * only exception to this is if we have a tuple with a
1458 * single item, and then swapping it will be OK anyway.
1460 if (alignment + 1 == fixed_size)
1466 guint16 *ptr = (guint16 *) serialised.data;
1468 g_assert_cmpint (serialised.size, ==, 2);
1469 *ptr = GUINT16_SWAP_LE_BE (*ptr);
1475 guint32 *ptr = (guint32 *) serialised.data;
1477 g_assert_cmpint (serialised.size, ==, 4);
1478 *ptr = GUINT32_SWAP_LE_BE (*ptr);
1484 guint64 *ptr = (guint64 *) serialised.data;
1486 g_assert_cmpint (serialised.size, ==, 8);
1487 *ptr = GUINT64_SWAP_LE_BE (*ptr);
1492 g_assert_not_reached ();
1496 /* else, we have a container that potentially contains
1497 * some children that need to be byteswapped.
1503 children = g_variant_serialised_n_children (serialised);
1504 for (i = 0; i < children; i++)
1506 GVariantSerialised child;
1508 child = g_variant_serialised_get_child (serialised, i);
1509 g_variant_serialised_byteswap (child);
1510 g_variant_type_info_unref (child.type_info);
1515 /* Normal form checking {{{2 */
1518 * g_variant_serialised_is_normal:
1519 * @serialised: a #GVariantSerialised
1521 * Determines, recursively if @serialised is in normal form. There is
1522 * precisely one normal form of serialised data for each possible value.
1524 * It is possible that multiple byte sequences form the serialised data
1525 * for a given value if, for example, the padding bytes are filled in
1526 * with something other than zeros, but only one form is the normal
1530 g_variant_serialised_is_normal (GVariantSerialised serialised)
1532 DISPATCH_CASES (serialised.type_info,
1534 return gvs_/**/,/**/_is_normal (serialised);
1538 /* some hard-coded terminal cases */
1539 switch (g_variant_type_info_get_type_char (serialised.type_info))
1541 case 'b': /* boolean */
1542 return serialised.data[0] < 2;
1544 case 's': /* string */
1545 return g_variant_serialiser_is_string (serialised.data,
1549 return g_variant_serialiser_is_object_path (serialised.data,
1553 return g_variant_serialiser_is_signature (serialised.data,
1557 /* all of the other types are fixed-sized numerical types for
1558 * which all possible values are valid (including various NaN
1559 * representations for floating point values).
1565 /* Validity-checking functions {{{2
1567 * Checks if strings, object paths and signature strings are valid.
1571 * g_variant_serialiser_is_string:
1572 * @data: a possible string
1573 * @size: the size of @data
1575 * Ensures that @data is a valid string with a nul terminator at the end
1576 * and no nul bytes embedded.
1579 g_variant_serialiser_is_string (gconstpointer data,
1584 g_utf8_validate (data, size, &end);
1586 return data == end - (size - 1);
1590 * g_variant_serialiser_is_object_path:
1591 * @data: a possible DBus object path
1592 * @size: the size of @data
1594 * Performs the checks for being a valid string.
1596 * Also, ensures that @data is a valid DBus object path, as per the DBus
1600 g_variant_serialiser_is_object_path (gconstpointer data,
1603 const gchar *string = data;
1606 if (!g_variant_serialiser_is_string (data, size))
1609 /* The path must begin with an ASCII '/' (integer 47) character */
1610 if (string[0] != '/')
1613 for (i = 1; string[i]; i++)
1614 /* Each element must only contain the ASCII characters
1615 * "[A-Z][a-z][0-9]_"
1617 if (g_ascii_isalnum (string[i]) || string[i] == '_')
1620 /* must consist of elements separated by slash characters. */
1621 else if (string[i] == '/')
1623 /* No element may be the empty string. */
1624 /* Multiple '/' characters cannot occur in sequence. */
1625 if (string[i - 1] == '/')
1632 /* A trailing '/' character is not allowed unless the path is the
1633 * root path (a single '/' character).
1635 if (i > 1 && string[i - 1] == '/')
1642 * g_variant_serialiser_is_signature:
1643 * @data: a possible DBus signature
1644 * @size: the size of @data
1646 * Performs the checks for being a valid string.
1648 * Also, ensures that @data is a valid DBus type signature, as per the
1649 * DBus specification.
1652 g_variant_serialiser_is_signature (gconstpointer data,
1655 const gchar *string = data;
1656 gsize first_invalid;
1658 if (!g_variant_serialiser_is_string (data, size))
1661 /* make sure no non-definite characters appear */
1662 first_invalid = strspn (string, "ybnqiuxthdvasog(){}");
1663 if (string[first_invalid])
1666 /* make sure each type string is well-formed */
1668 if (!g_variant_type_string_scan (string, NULL, &string))
1675 #define __G_VARIANT_SERIALISER_C__
1676 #include "galiasdef.c"
1678 /* vim:set foldmethod=marker: */