| /* |
| * Copyright © 2008 Ryan Lortie |
| * Copyright © 2010 Codethink Limited |
| * |
| * SPDX-License-Identifier: LGPL-2.1-or-later |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| * |
| * Author: Ryan Lortie <desrt@desrt.ca> |
| */ |
| |
| #include "config.h" |
| |
| #include "gvarianttypeinfo.h" |
| |
| #include <glib/gtestutils.h> |
| #include <glib/gthread.h> |
| #include <glib/gslice.h> |
| #include <glib/ghash.h> |
| #include <glib/grefcount.h> |
| |
| #include "glib_trace.h" |
| |
| /* < private > |
| * GVariantTypeInfo: |
| * |
| * This structure contains the necessary information to facilitate the |
| * serialization and fast deserialization of a given type of GVariant |
| * value. A GVariant instance holds a pointer to one of these |
| * structures to provide for efficient operation. |
| * |
| * The GVariantTypeInfo structures for all of the base types, plus the |
| * "variant" type are stored in a read-only static array. |
| * |
| * For container types, a hash table and reference counting is used to |
| * ensure that only one of these structures exists for any given type. |
| * In general, a container GVariantTypeInfo will exist for a given type |
| * only if one or more GVariant instances of that type exist or if |
| * another GVariantTypeInfo has that type as a subtype. For example, if |
| * a process contains a single GVariant instance with type "(asv)", then |
| * container GVariantTypeInfo structures will exist for "(asv)" and |
| * for "as" (note that "s" and "v" always exist in the static array). |
| * |
| * The trickiest part of GVariantTypeInfo (and in fact, the major reason |
| * for its existence) is the storage of somewhat magical constants that |
| * allow for O(1) lookups of items in tuples. This is described below. |
| * |
| * 'container_class' is set to 'a' or 'r' if the GVariantTypeInfo is |
| * contained inside of an ArrayInfo or TupleInfo, respectively. This |
| * allows the storage of the necessary additional information. |
| * |
| * 'fixed_size' is set to the fixed size of the type, if applicable, or |
| * 0 otherwise (since no type has a fixed size of 0). |
| * |
| * 'alignment' is set to one less than the alignment requirement for |
| * this type. This makes many operations much more convenient. |
| */ |
| struct _GVariantTypeInfo |
| { |
| gsize fixed_size; |
| guchar alignment; |
| guchar container_class; |
| }; |
| |
| /* Container types are reference counted. They also need to have their |
| * type string stored explicitly since it is not merely a single letter. |
| */ |
| typedef struct |
| { |
| GVariantTypeInfo info; |
| |
| gchar *type_string; |
| gatomicrefcount ref_count; |
| } ContainerInfo; |
| |
| /* For 'array' and 'maybe' types, we store some extra information on the |
| * end of the GVariantTypeInfo struct -- the element type (ie: "s" for |
| * "as"). The container GVariantTypeInfo structure holds a reference to |
| * the element typeinfo. |
| */ |
| typedef struct |
| { |
| ContainerInfo container; |
| |
| GVariantTypeInfo *element; |
| } ArrayInfo; |
| |
| /* For 'tuple' and 'dict entry' types, we store extra information for |
| * each member -- its type and how to find it inside the serialized data |
| * in O(1) time using 4 variables -- 'i', 'a', 'b', and 'c'. See the |
| * comment on GVariantMemberInfo in gvarianttypeinfo.h. |
| */ |
| typedef struct |
| { |
| ContainerInfo container; |
| |
| GVariantMemberInfo *members; |
| gsize n_members; |
| } TupleInfo; |
| |
| |
| /* Hard-code the base types in a constant array */ |
| static const GVariantTypeInfo g_variant_type_info_basic_table[24] = { |
| #define fixed_aligned(x) x, x - 1, 0 |
| #define not_a_type 0, 0, 0 |
| #define unaligned 0, 0, 0 |
| #define aligned(x) 0, x - 1, 0 |
| /* 'b' */ { fixed_aligned(1) }, /* boolean */ |
| /* 'c' */ { not_a_type }, |
| /* 'd' */ { fixed_aligned(8) }, /* double */ |
| /* 'e' */ { not_a_type }, |
| /* 'f' */ { not_a_type }, |
| /* 'g' */ { unaligned }, /* signature string */ |
| /* 'h' */ { fixed_aligned(4) }, /* file handle (int32) */ |
| /* 'i' */ { fixed_aligned(4) }, /* int32 */ |
| /* 'j' */ { not_a_type }, |
| /* 'k' */ { not_a_type }, |
| /* 'l' */ { not_a_type }, |
| /* 'm' */ { not_a_type }, |
| /* 'n' */ { fixed_aligned(2) }, /* int16 */ |
| /* 'o' */ { unaligned }, /* object path string */ |
| /* 'p' */ { not_a_type }, |
| /* 'q' */ { fixed_aligned(2) }, /* uint16 */ |
| /* 'r' */ { not_a_type }, |
| /* 's' */ { unaligned }, /* string */ |
| /* 't' */ { fixed_aligned(8) }, /* uint64 */ |
| /* 'u' */ { fixed_aligned(4) }, /* uint32 */ |
| /* 'v' */ { aligned(8) }, /* variant */ |
| /* 'w' */ { not_a_type }, |
| /* 'x' */ { fixed_aligned(8) }, /* int64 */ |
| /* 'y' */ { fixed_aligned(1) }, /* byte */ |
| #undef fixed_aligned |
| #undef not_a_type |
| #undef unaligned |
| #undef aligned |
| }; |
| |
| /* We need to have type strings to return for the base types. We store |
| * those in another array. Since all base type strings are single |
| * characters this is easy. By not storing pointers to strings into the |
| * GVariantTypeInfo itself, we save a bunch of relocations. |
| */ |
| static const char g_variant_type_info_basic_chars[24][2] = { |
| "b", " ", "d", " ", " ", "g", "h", "i", " ", " ", " ", " ", |
| "n", "o", " ", "q", " ", "s", "t", "u", "v", " ", "x", "y" |
| }; |
| |
| /* sanity checks to make debugging easier */ |
| static void |
| g_variant_type_info_check (const GVariantTypeInfo *info, |
| char container_class) |
| { |
| #ifndef G_DISABLE_ASSERT |
| g_assert (!container_class || info->container_class == container_class); |
| |
| /* alignment can only be one of these */ |
| g_assert (info->alignment == 0 || info->alignment == 1 || |
| info->alignment == 3 || info->alignment == 7); |
| |
| if (info->container_class) |
| { |
| ContainerInfo *container = (ContainerInfo *) info; |
| |
| /* extra checks for containers */ |
| g_assert (!g_atomic_ref_count_compare (&container->ref_count, 0)); |
| g_assert (container->type_string != NULL); |
| } |
| else |
| { |
| gint index; |
| |
| /* if not a container, then ensure that it is a valid member of |
| * the basic types table |
| */ |
| index = info - g_variant_type_info_basic_table; |
| |
| g_assert (G_N_ELEMENTS (g_variant_type_info_basic_table) == 24); |
| g_assert (G_N_ELEMENTS (g_variant_type_info_basic_chars) == 24); |
| g_assert (0 <= index && index < 24); |
| g_assert (g_variant_type_info_basic_chars[index][0] != ' '); |
| } |
| #endif /* !G_DISABLE_ASSERT */ |
| } |
| |
| /* < private > |
| * g_variant_type_info_get_type_string: |
| * @info: a #GVariantTypeInfo |
| * |
| * Gets the type string for @info. The string is nul-terminated. |
| */ |
| const gchar * |
| g_variant_type_info_get_type_string (GVariantTypeInfo *info) |
| { |
| g_variant_type_info_check (info, 0); |
| |
| if (info->container_class) |
| { |
| ContainerInfo *container = (ContainerInfo *) info; |
| |
| /* containers have their type string stored inside them */ |
| return container->type_string; |
| } |
| else |
| { |
| gint index; |
| |
| /* look up the type string in the base type array. the call to |
| * g_variant_type_info_check() above already ensured validity. |
| */ |
| index = info - g_variant_type_info_basic_table; |
| |
| return g_variant_type_info_basic_chars[index]; |
| } |
| } |
| |
| /* < private > |
| * g_variant_type_info_query: |
| * @info: a #GVariantTypeInfo |
| * @alignment: (out) (optional): the location to store the alignment, or %NULL |
| * @fixed_size: (out) (optional): the location to store the fixed size, or %NULL |
| * |
| * Queries @info to determine the alignment requirements and fixed size |
| * (if any) of the type. |
| * |
| * @fixed_size, if non-%NULL is set to the fixed size of the type, or 0 |
| * to indicate that the type is a variable-sized type. No type has a |
| * fixed size of 0. |
| * |
| * @alignment, if non-%NULL, is set to one less than the required |
| * alignment of the type. For example, for a 32bit integer, @alignment |
| * would be set to 3. This allows you to round an integer up to the |
| * proper alignment by performing the following efficient calculation: |
| * |
| * offset += ((-offset) & alignment); |
| */ |
| void |
| g_variant_type_info_query (GVariantTypeInfo *info, |
| guint *alignment, |
| gsize *fixed_size) |
| { |
| if (alignment) |
| *alignment = info->alignment; |
| |
| if (fixed_size) |
| *fixed_size = info->fixed_size; |
| } |
| |
| /* < private > |
| * g_variant_type_info_query_depth: |
| * @info: a #GVariantTypeInfo |
| * |
| * Queries @info to determine the depth of the type. |
| * |
| * See g_variant_type_string_get_depth_() for more details. |
| * |
| * Returns: depth of @info |
| * Since: 2.60 |
| */ |
| gsize |
| g_variant_type_info_query_depth (GVariantTypeInfo *info) |
| { |
| g_variant_type_info_check (info, 0); |
| |
| if (info->container_class) |
| { |
| ContainerInfo *container = (ContainerInfo *) info; |
| return g_variant_type_string_get_depth_ (container->type_string); |
| } |
| |
| return 1; |
| } |
| |
| /* == array == */ |
| #define GV_ARRAY_INFO_CLASS 'a' |
| static ArrayInfo * |
| GV_ARRAY_INFO (GVariantTypeInfo *info) |
| { |
| g_variant_type_info_check (info, GV_ARRAY_INFO_CLASS); |
| |
| return (ArrayInfo *) info; |
| } |
| |
| static void |
| array_info_free (GVariantTypeInfo *info) |
| { |
| ArrayInfo *array_info; |
| |
| g_assert (info->container_class == GV_ARRAY_INFO_CLASS); |
| array_info = (ArrayInfo *) info; |
| |
| g_variant_type_info_unref (array_info->element); |
| g_slice_free (ArrayInfo, array_info); |
| } |
| |
| static ContainerInfo * |
| array_info_new (const GVariantType *type) |
| { |
| ArrayInfo *info; |
| |
| info = g_slice_new (ArrayInfo); |
| info->container.info.container_class = GV_ARRAY_INFO_CLASS; |
| |
| info->element = g_variant_type_info_get (g_variant_type_element (type)); |
| info->container.info.alignment = info->element->alignment; |
| info->container.info.fixed_size = 0; |
| |
| return (ContainerInfo *) info; |
| } |
| |
| /* < private > |
| * g_variant_type_info_element: |
| * @info: a #GVariantTypeInfo for an array or maybe type |
| * |
| * Returns the element type for the array or maybe type. A reference is |
| * not added, so the caller must add their own. |
| */ |
| GVariantTypeInfo * |
| g_variant_type_info_element (GVariantTypeInfo *info) |
| { |
| return GV_ARRAY_INFO (info)->element; |
| } |
| |
| /* < private > |
| * g_variant_type_query_element: |
| * @info: a #GVariantTypeInfo for an array or maybe type |
| * @alignment: (out) (optional): the location to store the alignment, or %NULL |
| * @fixed_size: (out) (optional): the location to store the fixed size, or %NULL |
| * |
| * Returns the alignment requires and fixed size (if any) for the |
| * element type of the array. This call is a convenience wrapper around |
| * g_variant_type_info_element() and g_variant_type_info_query(). |
| */ |
| void |
| g_variant_type_info_query_element (GVariantTypeInfo *info, |
| guint *alignment, |
| gsize *fixed_size) |
| { |
| g_variant_type_info_query (GV_ARRAY_INFO (info)->element, |
| alignment, fixed_size); |
| } |
| |
| /* == tuple == */ |
| #define GV_TUPLE_INFO_CLASS 'r' |
| static TupleInfo * |
| GV_TUPLE_INFO (GVariantTypeInfo *info) |
| { |
| g_variant_type_info_check (info, GV_TUPLE_INFO_CLASS); |
| |
| return (TupleInfo *) info; |
| } |
| |
| static void |
| tuple_info_free (GVariantTypeInfo *info) |
| { |
| TupleInfo *tuple_info; |
| gsize i; |
| |
| g_assert (info->container_class == GV_TUPLE_INFO_CLASS); |
| tuple_info = (TupleInfo *) info; |
| |
| for (i = 0; i < tuple_info->n_members; i++) |
| g_variant_type_info_unref (tuple_info->members[i].type_info); |
| |
| g_slice_free1 (sizeof (GVariantMemberInfo) * tuple_info->n_members, |
| tuple_info->members); |
| g_slice_free (TupleInfo, tuple_info); |
| } |
| |
| static void |
| tuple_allocate_members (const GVariantType *type, |
| GVariantMemberInfo **members, |
| gsize *n_members) |
| { |
| const GVariantType *item_type; |
| gsize i = 0; |
| |
| *n_members = g_variant_type_n_items (type); |
| *members = g_slice_alloc (sizeof (GVariantMemberInfo) * *n_members); |
| |
| item_type = g_variant_type_first (type); |
| while (item_type) |
| { |
| GVariantMemberInfo *member = &(*members)[i++]; |
| |
| member->type_info = g_variant_type_info_get (item_type); |
| item_type = g_variant_type_next (item_type); |
| |
| if (member->type_info->fixed_size) |
| member->ending_type = G_VARIANT_MEMBER_ENDING_FIXED; |
| else if (item_type == NULL) |
| member->ending_type = G_VARIANT_MEMBER_ENDING_LAST; |
| else |
| member->ending_type = G_VARIANT_MEMBER_ENDING_OFFSET; |
| } |
| |
| g_assert (i == *n_members); |
| } |
| |
| /* this is g_variant_type_info_query for a given member of the tuple. |
| * before the access is done, it is ensured that the item is within |
| * range and %FALSE is returned if not. |
| */ |
| static gboolean |
| tuple_get_item (TupleInfo *info, |
| GVariantMemberInfo *item, |
| gsize *d, |
| gsize *e) |
| { |
| if (&info->members[info->n_members] == item) |
| return FALSE; |
| |
| *d = item->type_info->alignment; |
| *e = item->type_info->fixed_size; |
| return TRUE; |
| } |
| |
| /* Read the documentation for #GVariantMemberInfo in gvarianttype.h |
| * before attempting to understand this. |
| * |
| * This function adds one set of "magic constant" values (for one item |
| * in the tuple) to the table. |
| * |
| * The algorithm in tuple_generate_table() calculates values of 'a', 'b' |
| * and 'c' for each item, such that the procedure for finding the item |
| * is to start at the end of the previous variable-sized item, add 'a', |
| * then round up to the nearest multiple of 'b', then then add 'c'. |
| * Note that 'b' is stored in the usual "one less than" form. ie: |
| * |
| * start = ROUND_UP(prev_end + a, (b + 1)) + c; |
| * |
| * We tweak these values a little to allow for a slightly easier |
| * computation and more compact storage. |
| */ |
| static void |
| tuple_table_append (GVariantMemberInfo **items, |
| gsize i, |
| gsize a, |
| gsize b, |
| gsize c) |
| { |
| GVariantMemberInfo *item = (*items)++; |
| |
| /* We can shift multiples of the alignment size from 'c' into 'a'. |
| * As long as we're shifting whole multiples, it won't affect the |
| * result. This means that we can take the "aligned" portion off of |
| * 'c' and add it into 'a'. |
| * |
| * Imagine (for sake of clarity) that ROUND_10 rounds up to the |
| * nearest 10. It is clear that: |
| * |
| * ROUND_10(a) + c == ROUND_10(a + 10*(c / 10)) + (c % 10) |
| * |
| * ie: remove the 10s portion of 'c' and add it onto 'a'. |
| * |
| * To put some numbers on it, imagine we start with a = 34 and c = 27: |
| * |
| * ROUND_10(34) + 27 = 40 + 27 = 67 |
| * |
| * but also, we can split 27 up into 20 and 7 and do this: |
| * |
| * ROUND_10(34 + 20) + 7 = ROUND_10(54) + 7 = 60 + 7 = 67 |
| * ^^ ^ |
| * without affecting the result. We do that here. |
| * |
| * This reduction in the size of 'c' means that we can store it in a |
| * gchar instead of a gsize. Due to how the structure is packed, this |
| * ends up saving us 'two pointer sizes' per item in each tuple when |
| * allocating using GSlice. |
| */ |
| a += ~b & c; /* take the "aligned" part of 'c' and add to 'a' */ |
| c &= b; /* chop 'c' to contain only the unaligned part */ |
| |
| |
| /* Finally, we made one last adjustment. Recall: |
| * |
| * start = ROUND_UP(prev_end + a, (b + 1)) + c; |
| * |
| * Forgetting the '+ c' for the moment: |
| * |
| * ROUND_UP(prev_end + a, (b + 1)); |
| * |
| * we can do a "round up" operation by adding 1 less than the amount |
| * to round up to, then rounding down. ie: |
| * |
| * #define ROUND_UP(x, y) ROUND_DOWN(x + (y-1), y) |
| * |
| * Of course, for rounding down to a power of two, we can just mask |
| * out the appropriate number of low order bits: |
| * |
| * #define ROUND_DOWN(x, y) (x & ~(y - 1)) |
| * |
| * Which gives us |
| * |
| * #define ROUND_UP(x, y) (x + (y - 1) & ~(y - 1)) |
| * |
| * but recall that our alignment value 'b' is already "one less". |
| * This means that to round 'prev_end + a' up to 'b' we can just do: |
| * |
| * ((prev_end + a) + b) & ~b |
| * |
| * Associativity, and putting the 'c' back on: |
| * |
| * (prev_end + (a + b)) & ~b + c |
| * |
| * Now, since (a + b) is constant, we can just add 'b' to 'a' now and |
| * store that as the number to add to prev_end. Then we use ~b as the |
| * number to take a bitwise 'and' with. Finally, 'c' is added on. |
| * |
| * Note, however, that all the low order bits of the 'aligned' value |
| * are masked out and that all of the high order bits of 'c' have been |
| * "moved" to 'a' (in the previous step). This means that there are |
| * no overlapping bits in the addition -- so we can do a bitwise 'or' |
| * equivalently. |
| * |
| * This means that we can now compute the start address of a given |
| * item in the tuple using the algorithm given in the documentation |
| * for #GVariantMemberInfo: |
| * |
| * item_start = ((prev_end + a) & b) | c; |
| */ |
| |
| item->i = i; |
| item->a = a + b; |
| item->b = ~b; |
| item->c = c; |
| } |
| |
| static gsize |
| tuple_align (gsize offset, |
| guint alignment) |
| { |
| return offset + ((-offset) & alignment); |
| } |
| |
| /* This function is the heart of the algorithm for calculating 'i', 'a', |
| * 'b' and 'c' for each item in the tuple. |
| * |
| * Imagine we want to find the start of the "i" in the type "(su(qx)ni)". |
| * That's a string followed by a uint32, then a tuple containing a |
| * uint16 and an int64, then an int16, then our "i". In order to get to |
| * our "i" we: |
| * |
| * Start at the end of the string, align to 4 (for the uint32), add 4. |
| * Align to 8, add 16 (for the tuple). Align to 2, add 2 (for the |
| * int16). Then we're there. It turns out that, given 3 simple rules, |
| * we can flatten this iteration into one addition, one alignment, then |
| * one more addition. |
| * |
| * The loop below plays through each item in the tuple, querying its |
| * alignment and fixed_size into 'd' and 'e', respectively. At all |
| * times the variables 'a', 'b', and 'c' are maintained such that in |
| * order to get to the current point, you add 'a', align to 'b' then add |
| * 'c'. 'b' is kept in "one less than" form. For each item, the proper |
| * alignment is applied to find the values of 'a', 'b' and 'c' to get to |
| * the start of that item. Those values are recorded into the table. |
| * The fixed size of the item (if applicable) is then added on. |
| * |
| * These 3 rules are how 'a', 'b' and 'c' are modified for alignment and |
| * addition of fixed size. They have been proven correct but are |
| * presented here, without proof: |
| * |
| * 1) in order to "align to 'd'" where 'd' is less than or equal to the |
| * largest level of alignment seen so far ('b'), you align 'c' to |
| * 'd'. |
| * 2) in order to "align to 'd'" where 'd' is greater than the largest |
| * level of alignment seen so far, you add 'c' aligned to 'b' to the |
| * value of 'a', set 'b' to 'd' (ie: increase the 'largest alignment |
| * seen') and reset 'c' to 0. |
| * 3) in order to "add 'e'", just add 'e' to 'c'. |
| */ |
| static void |
| tuple_generate_table (TupleInfo *info) |
| { |
| GVariantMemberInfo *items = info->members; |
| gsize i = -1, a = 0, b = 0, c = 0, d, e; |
| |
| /* iterate over each item in the tuple. |
| * 'd' will be the alignment of the item (in one-less form) |
| * 'e' will be the fixed size (or 0 for variable-size items) |
| */ |
| while (tuple_get_item (info, items, &d, &e)) |
| { |
| /* align to 'd' */ |
| if (d <= b) |
| c = tuple_align (c, d); /* rule 1 */ |
| else |
| a += tuple_align (c, b), b = d, c = 0; /* rule 2 */ |
| |
| /* the start of the item is at this point (ie: right after we |
| * have aligned for it). store this information in the table. |
| */ |
| tuple_table_append (&items, i, a, b, c); |
| |
| /* "move past" the item by adding in its size. */ |
| if (e == 0) |
| /* variable size: |
| * |
| * we'll have an offset stored to mark the end of this item, so |
| * just bump the offset index to give us a new starting point |
| * and reset all the counters. |
| */ |
| i++, a = b = c = 0; |
| else |
| /* fixed size */ |
| c += e; /* rule 3 */ |
| } |
| } |
| |
| static void |
| tuple_set_base_info (TupleInfo *info) |
| { |
| GVariantTypeInfo *base = &info->container.info; |
| |
| if (info->n_members > 0) |
| { |
| GVariantMemberInfo *m; |
| |
| /* the alignment requirement of the tuple is the alignment |
| * requirement of its largest item. |
| */ |
| base->alignment = 0; |
| for (m = info->members; m < &info->members[info->n_members]; m++) |
| /* can find the max of a list of "one less than" powers of two |
| * by 'or'ing them |
| */ |
| base->alignment |= m->type_info->alignment; |
| |
| m--; /* take 'm' back to the last item */ |
| |
| /* the structure only has a fixed size if no variable-size |
| * offsets are stored and the last item is fixed-sized too (since |
| * an offset is never stored for the last item). |
| */ |
| if (m->i == (gsize) -1 && m->type_info->fixed_size) |
| /* in that case, the fixed size can be found by finding the |
| * start of the last item (in the usual way) and adding its |
| * fixed size. |
| * |
| * if a tuple has a fixed size then it is always a multiple of |
| * the alignment requirement (to make packing into arrays |
| * easier) so we round up to that here. |
| */ |
| base->fixed_size = |
| tuple_align (((m->a & m->b) | m->c) + m->type_info->fixed_size, |
| base->alignment); |
| else |
| /* else, the tuple is not fixed size */ |
| base->fixed_size = 0; |
| } |
| else |
| { |
| /* the empty tuple: '()'. |
| * |
| * has a size of 1 and a no alignment requirement. |
| * |
| * It has a size of 1 (not 0) for two practical reasons: |
| * |
| * 1) So we can determine how many of them are in an array |
| * without dividing by zero or without other tricks. |
| * |
| * 2) Even if we had some trick to know the number of items in |
| * the array (as GVariant did at one time) this would open a |
| * potential denial of service attack: an attacker could send |
| * you an extremely small array (in terms of number of bytes) |
| * containing trillions of zero-sized items. If you iterated |
| * over this array you would effectively infinite-loop your |
| * program. By forcing a size of at least one, we bound the |
| * amount of computation done in response to a message to a |
| * reasonable function of the size of that message. |
| */ |
| base->alignment = 0; |
| base->fixed_size = 1; |
| } |
| } |
| |
| static ContainerInfo * |
| tuple_info_new (const GVariantType *type) |
| { |
| TupleInfo *info; |
| |
| info = g_slice_new (TupleInfo); |
| info->container.info.container_class = GV_TUPLE_INFO_CLASS; |
| |
| tuple_allocate_members (type, &info->members, &info->n_members); |
| tuple_generate_table (info); |
| tuple_set_base_info (info); |
| |
| return (ContainerInfo *) info; |
| } |
| |
| /* < private > |
| * g_variant_type_info_n_members: |
| * @info: a #GVariantTypeInfo for a tuple or dictionary entry type |
| * |
| * Returns the number of members in a tuple or dictionary entry type. |
| * For a dictionary entry this will always be 2. |
| */ |
| gsize |
| g_variant_type_info_n_members (GVariantTypeInfo *info) |
| { |
| return GV_TUPLE_INFO (info)->n_members; |
| } |
| |
| /* < private > |
| * g_variant_type_info_member_info: |
| * @info: a #GVariantTypeInfo for a tuple or dictionary entry type |
| * @index: the member to fetch information for |
| * |
| * Returns the #GVariantMemberInfo for a given member. See |
| * documentation for that structure for why you would want this |
| * information. |
| * |
| * @index must refer to a valid child (ie: strictly less than |
| * g_variant_type_info_n_members() returns). |
| */ |
| const GVariantMemberInfo * |
| g_variant_type_info_member_info (GVariantTypeInfo *info, |
| gsize index) |
| { |
| TupleInfo *tuple_info = GV_TUPLE_INFO (info); |
| |
| if (index < tuple_info->n_members) |
| return &tuple_info->members[index]; |
| |
| return NULL; |
| } |
| |
| /* == new/ref/unref == */ |
| static GRecMutex g_variant_type_info_lock; |
| static GHashTable *g_variant_type_info_table; |
| |
| /* < private > |
| * g_variant_type_info_get: |
| * @type: a #GVariantType |
| * |
| * Returns a reference to a #GVariantTypeInfo for @type. |
| * |
| * If an info structure already exists for this type, a new reference is |
| * returned. If not, the required calculations are performed and a new |
| * info structure is returned. |
| * |
| * It is appropriate to call g_variant_type_info_unref() on the return |
| * value. |
| */ |
| GVariantTypeInfo * |
| g_variant_type_info_get (const GVariantType *type) |
| { |
| char type_char; |
| |
| type_char = g_variant_type_peek_string (type)[0]; |
| |
| if (type_char == G_VARIANT_TYPE_INFO_CHAR_MAYBE || |
| type_char == G_VARIANT_TYPE_INFO_CHAR_ARRAY || |
| type_char == G_VARIANT_TYPE_INFO_CHAR_TUPLE || |
| type_char == G_VARIANT_TYPE_INFO_CHAR_DICT_ENTRY) |
| { |
| GVariantTypeInfo *info; |
| gchar *type_string; |
| |
| type_string = g_variant_type_dup_string (type); |
| |
| g_rec_mutex_lock (&g_variant_type_info_lock); |
| |
| if (g_variant_type_info_table == NULL) |
| g_variant_type_info_table = g_hash_table_new (g_str_hash, |
| g_str_equal); |
| info = g_hash_table_lookup (g_variant_type_info_table, type_string); |
| |
| if (info == NULL) |
| { |
| ContainerInfo *container; |
| |
| if (type_char == G_VARIANT_TYPE_INFO_CHAR_MAYBE || |
| type_char == G_VARIANT_TYPE_INFO_CHAR_ARRAY) |
| { |
| container = array_info_new (type); |
| } |
| else /* tuple or dict entry */ |
| { |
| container = tuple_info_new (type); |
| } |
| |
| info = (GVariantTypeInfo *) container; |
| container->type_string = type_string; |
| g_atomic_ref_count_init (&container->ref_count); |
| |
| TRACE(GLIB_VARIANT_TYPE_INFO_NEW(info, container->type_string)); |
| |
| g_hash_table_insert (g_variant_type_info_table, type_string, info); |
| type_string = NULL; |
| } |
| else |
| g_variant_type_info_ref (info); |
| |
| g_rec_mutex_unlock (&g_variant_type_info_lock); |
| g_variant_type_info_check (info, 0); |
| g_free (type_string); |
| |
| return info; |
| } |
| else |
| { |
| const GVariantTypeInfo *info; |
| int index; |
| |
| index = type_char - 'b'; |
| g_assert (G_N_ELEMENTS (g_variant_type_info_basic_table) == 24); |
| g_assert_cmpint (0, <=, index); |
| g_assert_cmpint (index, <, 24); |
| |
| info = g_variant_type_info_basic_table + index; |
| g_variant_type_info_check (info, 0); |
| |
| TRACE(GLIB_VARIANT_TYPE_INFO_NEW(info, g_variant_type_info_basic_chars[index])); |
| |
| return (GVariantTypeInfo *) info; |
| } |
| } |
| |
| /* < private > |
| * g_variant_type_info_ref: |
| * @info: a #GVariantTypeInfo |
| * |
| * Adds a reference to @info. |
| */ |
| GVariantTypeInfo * |
| g_variant_type_info_ref (GVariantTypeInfo *info) |
| { |
| g_variant_type_info_check (info, 0); |
| |
| if (info->container_class) |
| { |
| ContainerInfo *container = (ContainerInfo *) info; |
| |
| g_atomic_ref_count_inc (&container->ref_count); |
| } |
| |
| return info; |
| } |
| |
| /* < private > |
| * g_variant_type_info_unref: |
| * @info: a #GVariantTypeInfo |
| * |
| * Releases a reference held on @info. This may result in @info being |
| * freed. |
| */ |
| void |
| g_variant_type_info_unref (GVariantTypeInfo *info) |
| { |
| g_variant_type_info_check (info, 0); |
| |
| if (info->container_class) |
| { |
| ContainerInfo *container = (ContainerInfo *) info; |
| |
| g_rec_mutex_lock (&g_variant_type_info_lock); |
| if (g_atomic_ref_count_dec (&container->ref_count)) |
| { |
| |
| TRACE(GLIB_VARIANT_TYPE_INFO_FREE(info)); |
| |
| g_hash_table_remove (g_variant_type_info_table, |
| container->type_string); |
| if (g_hash_table_size (g_variant_type_info_table) == 0) |
| { |
| g_hash_table_unref (g_variant_type_info_table); |
| g_variant_type_info_table = NULL; |
| } |
| g_rec_mutex_unlock (&g_variant_type_info_lock); |
| |
| g_free (container->type_string); |
| |
| if (info->container_class == GV_ARRAY_INFO_CLASS) |
| array_info_free (info); |
| |
| else if (info->container_class == GV_TUPLE_INFO_CLASS) |
| tuple_info_free (info); |
| |
| else |
| g_assert_not_reached (); |
| } |
| else |
| g_rec_mutex_unlock (&g_variant_type_info_lock); |
| } |
| } |
| |
| void |
| g_variant_type_info_assert_no_infos (void) |
| { |
| g_assert (g_variant_type_info_table == NULL); |
| } |