src/data_internal.h

   1 /*
   2  * Copyright (c) 2009-2012 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_APACHE_LICENSE_HEADER_START@
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  *
  18  * @APPLE_APACHE_LICENSE_HEADER_END@
  19  */
  20
  21 /*
  22  * IMPORTANT: This header file describes INTERNAL interfaces to libdispatch
  23  * which are subject to change in future releases of Mac OS X. Any applications
  24  * relying on these interfaces WILL break.
  25  */
  26
  27 #ifndef __DISPATCH_DATA_INTERNAL__
  28 #define __DISPATCH_DATA_INTERNAL__
  29
  30 #ifndef __DISPATCH_INDIRECT__
  31 #error "Please #include <dispatch/dispatch.h> instead of this file directly."
  32 #include <dispatch/base.h> // for HeaderDoc
  33 #endif
  34
  35 typedef struct range_record_s {
  36         dispatch_data_t data_object;
  37         size_t from;
  38         size_t length;
  39 } range_record;
  40
  41 #if OS_OBJECT_HAVE_OBJC2
  42 #define DISPATCH_DATA_IS_BRIDGED_TO_NSDATA 1
  43 #else
  44 #define DISPATCH_DATA_IS_BRIDGED_TO_NSDATA 0
  45 #endif
  46
  47 #if DISPATCH_DATA_IS_BRIDGED_TO_NSDATA
  48 DISPATCH_OBJC_CLASS_DECL(data);
  49 DISPATCH_OBJC_CLASS_DECL(data_empty);
  50 _OS_OBJECT_DECL_PROTOCOL(dispatch_data, dispatch_object);
  51 #define DISPATCH_DATA_CLASS DISPATCH_VTABLE(data)
  52 #define DISPATCH_DATA_EMPTY_CLASS DISPATCH_VTABLE(data_empty)
  53 #else
  54 DISPATCH_CLASS_DECL(data);
  55 #define DISPATCH_DATA_CLASS DISPATCH_VTABLE(data)
  56 #endif // DISPATCH_DATA_IS_BRIDGED_TO_NSDATA
  57
  58 struct dispatch_data_s {
  59 #if DISPATCH_DATA_IS_BRIDGED_TO_NSDATA
  60         const void *do_vtable;
  61         dispatch_queue_t do_targetq;
  62         void *ctxt;
  63         void *finalizer;
  64 #else
  65         DISPATCH_OBJECT_HEADER(data);
  66 #endif // DISPATCH_DATA_IS_BRIDGED_TO_NSDATA
  67         const void *buf;
  68         dispatch_block_t destructor;
  69         size_t size, num_records;
  70         range_record records[0];
  71 };
  72
  73 DISPATCH_ALWAYS_INLINE
  74 static inline bool
  75 _dispatch_data_leaf(struct dispatch_data_s *dd)
  76 {
  77         return dd->num_records == 0;
  78 }
  79
  80 /*
  81  * This is about the number of records required to hold that dispatch data
  82  * if it's not a leaf. Callers either want that value, or have to special
  83  * case the case when the dispatch data *is* a leaf before (and that the actual
  84  * embedded record count of that dispatch data is 0)
  85  */
  86 DISPATCH_ALWAYS_INLINE
  87 static inline size_t
  88 _dispatch_data_num_records(struct dispatch_data_s *dd)
  89 {
  90         return dd->num_records ?: 1;
  91 }
  92
  93 typedef dispatch_data_t (*dispatch_transform_t)(dispatch_data_t data);
  94
  95 struct dispatch_data_format_type_s {
  96         uint64_t type;
  97         uint64_t input_mask;
  98         uint64_t output_mask;
  99         dispatch_transform_t decode;
 100         dispatch_transform_t encode;
 101 };
 102
 103 void dispatch_data_init(dispatch_data_t data, const void *buffer, size_t size,
 104                 dispatch_block_t destructor);
 105 void _dispatch_data_dispose(dispatch_data_t data);
 106 size_t _dispatch_data_debug(dispatch_data_t data, char* buf, size_t bufsiz);
 107 const void*
 108 _dispatch_data_get_flattened_bytes(struct dispatch_data_s *dd);
 109
 110 #if !defined(__cplusplus)
 111 extern const dispatch_block_t _dispatch_data_destructor_inline;
 112 #define DISPATCH_DATA_DESTRUCTOR_INLINE (_dispatch_data_destructor_inline)
 113
 114 /*
 115  * the out parameters are about seeing "through" trivial subranges
 116  * so for something like this: dd = { subrange [ dd1, offset1 ] },
 117  * this will return { dd1, offset + offset1 }
 118  *
 119  * If the dispatch object isn't a trivial subrange, it returns { dd, offset }
 120  */
 121 DISPATCH_ALWAYS_INLINE
 122 static inline const void*
 123 _dispatch_data_map_direct(struct dispatch_data_s *dd, size_t offset,
 124                 struct dispatch_data_s **dd_out, size_t *from_out)
 125 {
 126         const void *buffer = NULL;
 127
 128         dispatch_assert(dd->size);
 129         if (slowpath(!_dispatch_data_leaf(dd)) &&
 130                         _dispatch_data_num_records(dd) == 1) {
 131                 offset += dd->records[0].from;
 132                 dd = (struct dispatch_data_s *)dd->records[0].data_object;
 133         }
 134
 135         if (fastpath(_dispatch_data_leaf(dd))) {
 136                 buffer = dd->buf + offset;
 137         } else {
 138                 buffer = os_atomic_load((void **)&dd->buf, relaxed);
 139                 if (buffer) {
 140                         buffer += offset;
 141                 }
 142         }
 143         if (dd_out) *dd_out = dd;
 144         if (from_out) *from_out = offset;
 145         return buffer;
 146 }
 147
 148 #endif // !defined(__cplusplus)
 149
 150 #endif // __DISPATCH_DATA_INTERNAL__