src/io_internal.h

   1 /*
   2  * Copyright (c) 2009-2013 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_IO_INTERNAL__
  28 #define __DISPATCH_IO_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 #define _DISPATCH_IO_LABEL_SIZE 16
  36
  37 #if TARGET_OS_EMBEDDED // rdar://problem/9032036
  38 #define DIO_MAX_CHUNK_PAGES                             128u //  512kB chunk size
  39 #else
  40 #define DIO_MAX_CHUNK_PAGES                             256u // 1024kB chunk size
  41 #endif
  42
  43 #define DIO_DEFAULT_LOW_WATER_CHUNKS      1u // default low-water mark
  44 #define DIO_MAX_PENDING_IO_REQS                   6u // Pending I/O read advises
  45
  46 typedef unsigned int dispatch_op_direction_t;
  47 enum {
  48         DOP_DIR_READ = 0,
  49         DOP_DIR_WRITE,
  50         DOP_DIR_MAX,
  51         DOP_DIR_IGNORE = UINT_MAX,
  52 };
  53
  54 typedef unsigned int dispatch_op_flags_t;
  55 #define DOP_DEFAULT             0u // check conditions to determine delivery
  56 #define DOP_DELIVER             1u // always deliver operation
  57 #define DOP_DONE                2u // operation is done (implies deliver)
  58 #define DOP_STOP                4u // operation interrupted by chan stop (implies done)
  59 #define DOP_NO_EMPTY    8u // don't deliver empty data
  60
  61 // dispatch_io_t atomic_flags
  62 #define DIO_CLOSED              1u // channel has been closed
  63 #define DIO_STOPPED             2u // channel has been stopped (implies closed)
  64
  65 DISPATCH_DECL_INTERNAL(dispatch_operation);
  66 DISPATCH_DECL_INTERNAL(dispatch_disk);
  67
  68 struct dispatch_stream_s {
  69         dispatch_queue_t dq;
  70         dispatch_source_t source;
  71         dispatch_operation_t op;
  72         bool source_running;
  73         TAILQ_HEAD(, dispatch_operation_s) operations[2];
  74 };
  75
  76 typedef struct dispatch_stream_s *dispatch_stream_t;
  77
  78 struct dispatch_io_path_data_s {
  79         dispatch_io_t channel;
  80         int oflag;
  81         mode_t mode;
  82         size_t pathlen;
  83         char path[];
  84 };
  85
  86 typedef struct dispatch_io_path_data_s *dispatch_io_path_data_t;
  87
  88 struct dispatch_stat_s {
  89         dev_t dev;
  90         mode_t mode;
  91 };
  92
  93 DISPATCH_CLASS_DECL(disk);
  94 struct dispatch_disk_s {
  95         DISPATCH_STRUCT_HEADER(disk);
  96         dev_t dev;
  97         TAILQ_HEAD(dispatch_disk_operations_s, dispatch_operation_s) operations;
  98         dispatch_operation_t cur_rq;
  99         dispatch_queue_t pick_queue;
 100
 101         size_t free_idx;
 102         size_t req_idx;
 103         size_t advise_idx;
 104         bool io_active;
 105         int err;
 106         TAILQ_ENTRY(dispatch_disk_s) disk_list;
 107         size_t advise_list_depth;
 108         dispatch_operation_t advise_list[];
 109 };
 110
 111 struct dispatch_fd_entry_s {
 112         dispatch_fd_t fd;
 113         dispatch_io_path_data_t path_data;
 114         int orig_flags, orig_nosigpipe, err;
 115 #if DISPATCH_USE_GUARDED_FD_CHANGE_FDGUARD
 116         int orig_fd_flags;
 117 #endif
 118 #if DISPATCH_USE_GUARDED_FD
 119         unsigned int guard_flags;
 120 #endif
 121         struct dispatch_stat_s stat;
 122         dispatch_stream_t streams[2];
 123         dispatch_disk_t disk;
 124         dispatch_queue_t close_queue, barrier_queue;
 125         dispatch_group_t barrier_group;
 126         dispatch_io_t convenience_channel;
 127         TAILQ_HEAD(, dispatch_operation_s) stream_ops;
 128         TAILQ_ENTRY(dispatch_fd_entry_s) fd_list;
 129 };
 130
 131 typedef struct dispatch_fd_entry_s *dispatch_fd_entry_t;
 132
 133 typedef struct dispatch_io_param_s {
 134         dispatch_io_type_t type; // STREAM OR RANDOM
 135         size_t low;
 136         size_t high;
 137         uint64_t interval;
 138         unsigned long interval_flags;
 139 } dispatch_io_param_s;
 140
 141 DISPATCH_CLASS_DECL(operation);
 142 struct dispatch_operation_s {
 143         DISPATCH_STRUCT_HEADER(operation);
 144         dispatch_queue_t op_q;
 145         dispatch_op_direction_t direction; // READ OR WRITE
 146         dispatch_io_param_s params;
 147         off_t offset;
 148         size_t length;
 149         int err;
 150         dispatch_io_handler_t handler;
 151         dispatch_io_t channel;
 152         dispatch_fd_entry_t fd_entry;
 153         dispatch_source_t timer;
 154         bool active;
 155         off_t advise_offset;
 156         void* buf;
 157         dispatch_op_flags_t flags;
 158         size_t buf_siz, buf_len, undelivered, total;
 159         dispatch_data_t buf_data, data;
 160         TAILQ_ENTRY(dispatch_operation_s) operation_list;
 161         // the request list in the fd_entry stream_ops
 162         TAILQ_ENTRY(dispatch_operation_s) stream_list;
 163 };
 164
 165 DISPATCH_CLASS_DECL(io);
 166 struct dispatch_io_s {
 167         DISPATCH_STRUCT_HEADER(io);
 168         dispatch_queue_t queue, barrier_queue;
 169         dispatch_group_t barrier_group;
 170         dispatch_io_param_s params;
 171         dispatch_fd_entry_t fd_entry;
 172         unsigned int atomic_flags;
 173         dispatch_fd_t fd, fd_actual;
 174         off_t f_ptr;
 175         int err; // contains creation errors only
 176 };
 177
 178 void _dispatch_io_set_target_queue(dispatch_io_t channel, dispatch_queue_t dq);
 179 size_t _dispatch_io_debug(dispatch_io_t channel, char* buf, size_t bufsiz);
 180 void _dispatch_io_dispose(dispatch_io_t channel);
 181 size_t _dispatch_operation_debug(dispatch_operation_t op, char* buf,
 182                 size_t bufsiz);
 183 void _dispatch_operation_dispose(dispatch_operation_t operation);
 184 void _dispatch_disk_dispose(dispatch_disk_t disk);
 185
 186 #endif // __DISPATCH_IO_INTERNAL__