src/io_internal.h

   1 /*
   2  * Copyright (c) 2009-2011 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 #ifndef DISPATCH_IO_DEBUG
  38 #define DISPATCH_IO_DEBUG 0
  39 #endif
  40
  41 #if TARGET_OS_EMBEDDED // rdar://problem/9032036
  42 #define DIO_MAX_CHUNK_PAGES                             128u //  512kB chunk size
  43 #else
  44 #define DIO_MAX_CHUNK_PAGES                             256u // 1024kB chunk size
  45 #endif
  46
  47 #define DIO_DEFAULT_LOW_WATER_CHUNKS      1u // default low-water mark
  48 #define DIO_MAX_PENDING_IO_REQS                   6u // Pending I/O read advises
  49
  50 typedef unsigned int dispatch_op_direction_t;
  51 enum {
  52         DOP_DIR_READ = 0,
  53         DOP_DIR_WRITE,
  54         DOP_DIR_MAX,
  55         DOP_DIR_IGNORE = UINT_MAX,
  56 };
  57
  58 typedef unsigned int dispatch_op_flags_t;
  59 #define DOP_DEFAULT             0u // check conditions to determine delivery
  60 #define DOP_DELIVER             1u // always deliver operation
  61 #define DOP_DONE                2u // operation is done (implies deliver)
  62 #define DOP_STOP                4u // operation interrupted by chan stop (implies done)
  63 #define DOP_NO_EMPTY    8u // don't deliver empty data
  64
  65 // dispatch_io_t atomic_flags
  66 #define DIO_CLOSED              1u // channel has been closed
  67 #define DIO_STOPPED             2u // channel has been stopped (implies closed)
  68
  69 #define _dispatch_io_data_retain(x) dispatch_retain(x)
  70 #define _dispatch_io_data_release(x) dispatch_release(x)
  71
  72 #if DISPATCH_IO_DEBUG
  73 #define _dispatch_io_debug(msg, fd, args...) \
  74         _dispatch_debug("fd %d: " msg, (fd), ##args)
  75 #else
  76 #define _dispatch_io_debug(msg, fd, args...)
  77 #endif
  78
  79 DISPATCH_DECL_INTERNAL(dispatch_operation);
  80 DISPATCH_DECL_INTERNAL(dispatch_disk);
  81
  82 struct dispatch_stream_s {
  83         dispatch_queue_t dq;
  84         dispatch_source_t source;
  85         dispatch_operation_t op;
  86         bool source_running;
  87         TAILQ_HEAD(, dispatch_operation_s) operations[2];
  88 };
  89
  90 typedef struct dispatch_stream_s *dispatch_stream_t;
  91
  92 struct dispatch_io_path_data_s {
  93         dispatch_io_t channel;
  94         int oflag;
  95         mode_t mode;
  96         size_t pathlen;
  97         char path[];
  98 };
  99
 100 typedef struct dispatch_io_path_data_s *dispatch_io_path_data_t;
 101
 102 struct dispatch_stat_s {
 103         dev_t dev;
 104         mode_t mode;
 105 };
 106
 107 DISPATCH_CLASS_DECL(disk);
 108 struct dispatch_disk_s {
 109         DISPATCH_STRUCT_HEADER(disk);
 110         dev_t dev;
 111         TAILQ_HEAD(dispatch_disk_operations_s, dispatch_operation_s) operations;
 112         dispatch_operation_t cur_rq;
 113         dispatch_queue_t pick_queue;
 114
 115         size_t free_idx;
 116         size_t req_idx;
 117         size_t advise_idx;
 118         bool io_active;
 119         int err;
 120         TAILQ_ENTRY(dispatch_disk_s) disk_list;
 121         size_t advise_list_depth;
 122         dispatch_operation_t advise_list[];
 123 };
 124
 125 struct dispatch_fd_entry_s {
 126         dispatch_fd_t fd;
 127         dispatch_io_path_data_t path_data;
 128         int orig_flags, orig_nosigpipe, err;
 129         struct dispatch_stat_s stat;
 130         dispatch_stream_t streams[2];
 131         dispatch_disk_t disk;
 132         dispatch_queue_t close_queue, barrier_queue;
 133         dispatch_group_t barrier_group;
 134         dispatch_io_t convenience_channel;
 135         TAILQ_HEAD(, dispatch_operation_s) stream_ops;
 136         TAILQ_ENTRY(dispatch_fd_entry_s) fd_list;
 137 };
 138
 139 typedef struct dispatch_fd_entry_s *dispatch_fd_entry_t;
 140
 141 typedef struct dispatch_io_param_s {
 142         dispatch_io_type_t type; // STREAM OR RANDOM
 143         size_t low;
 144         size_t high;
 145         uint64_t interval;
 146         unsigned long interval_flags;
 147 } dispatch_io_param_s;
 148
 149 DISPATCH_CLASS_DECL(operation);
 150 struct dispatch_operation_s {
 151         DISPATCH_STRUCT_HEADER(operation);
 152         dispatch_queue_t op_q;
 153         dispatch_op_direction_t direction; // READ OR WRITE
 154         dispatch_io_param_s params;
 155         off_t offset;
 156         size_t length;
 157         int err;
 158         dispatch_io_handler_t handler;
 159         dispatch_io_t channel;
 160         dispatch_fd_entry_t fd_entry;
 161         dispatch_source_t timer;
 162         bool active;
 163         int count;
 164         off_t advise_offset;
 165         void* buf;
 166         dispatch_op_flags_t flags;
 167         size_t buf_siz, buf_len, undelivered, total;
 168         dispatch_data_t buf_data, data;
 169         TAILQ_ENTRY(dispatch_operation_s) operation_list;
 170         // the request list in the fd_entry stream_ops
 171         TAILQ_ENTRY(dispatch_operation_s) stream_list;
 172 };
 173
 174 DISPATCH_CLASS_DECL(io);
 175 struct dispatch_io_s {
 176         DISPATCH_STRUCT_HEADER(io);
 177         dispatch_queue_t queue, barrier_queue;
 178         dispatch_group_t barrier_group;
 179         dispatch_io_param_s params;
 180         dispatch_fd_entry_t fd_entry;
 181         unsigned int atomic_flags;
 182         dispatch_fd_t fd, fd_actual;
 183         off_t f_ptr;
 184         int err; // contains creation errors only
 185 };
 186
 187 void _dispatch_io_set_target_queue(dispatch_io_t channel, dispatch_queue_t dq);
 188 void _dispatch_io_dispose(dispatch_io_t channel);
 189 void _dispatch_operation_dispose(dispatch_operation_t operation);
 190 void _dispatch_disk_dispose(dispatch_disk_t disk);
 191
 192 #endif // __DISPATCH_IO_INTERNAL__