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
46typedef unsigned int dispatch_op_direction_t;
47enum {
48	DOP_DIR_READ = 0,
49	DOP_DIR_WRITE,
50	DOP_DIR_MAX,
51	DOP_DIR_IGNORE = UINT_MAX,
52};
53
54typedef 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
65DISPATCH_DECL_INTERNAL(dispatch_operation);
66DISPATCH_DECL_INTERNAL(dispatch_disk);
67
68struct 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
76typedef struct dispatch_stream_s *dispatch_stream_t;
77
78struct 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
86typedef struct dispatch_io_path_data_s *dispatch_io_path_data_t;
87
88struct dispatch_stat_s {
89	dev_t dev;
90	mode_t mode;
91};
92
93DISPATCH_CLASS_DECL(disk);
94struct 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
111struct 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
131typedef struct dispatch_fd_entry_s *dispatch_fd_entry_t;
132
133typedef 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
141DISPATCH_CLASS_DECL(operation);
142struct 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
165DISPATCH_CLASS_DECL(io);
166struct 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
178void _dispatch_io_set_target_queue(dispatch_io_t channel, dispatch_queue_t dq);
179size_t _dispatch_io_debug(dispatch_io_t channel, char* buf, size_t bufsiz);
180void _dispatch_io_dispose(dispatch_io_t channel);
181size_t _dispatch_operation_debug(dispatch_operation_t op, char* buf,
182		size_t bufsiz);
183void _dispatch_operation_dispose(dispatch_operation_t operation);
184void _dispatch_disk_dispose(dispatch_disk_t disk);
185
186#endif // __DISPATCH_IO_INTERNAL__
187