1 /* Licensed under LGPLv2.1+ - see LICENSE file for details */
7 * struct io_plan - a plan of what I/O to do.
8 * @pollflag: POLLIN or POLLOUT.
9 * @io: function to call when fd is available for @pollflag.
10 * @next: function to call after @io returns true.
11 * @next_arg: argument to @next.
12 * @u: scratch area for I/O.
14 * When the fd is POLLIN or POLLOUT (according to @pollflag), @io is
15 * called. If it returns -1, io_close() becomed the new plan (and errno
16 * is saved). If it returns 1, @next is called, otherwise @io is
17 * called again when @pollflag is available.
19 * You can use this to write your own io_plan functions.
23 /* Only NULL if idle. */
24 int (*io)(int fd, struct io_plan *plan);
25 /* Only NULL if closing. */
26 struct io_plan (*next)(struct io_conn *, void *arg);
66 * io_debug_conn - routine to select connection(s) to debug.
68 * If this is set, the routine should return true if the connection is a
69 * debugging candidate. If so, the callchain for I/O operations on this
70 * connection will be linear, for easier use of a debugger.
72 * You will also see calls to any callbacks which wake the connection
73 * which is being debugged.
76 * static bool debug_all(struct io_conn *conn)
81 * io_debug_conn = debug_all;
83 extern bool (*io_debug_conn)(struct io_conn *conn);
86 * io_debug - if we're debugging the current connection, call immediately.
88 * This determines if we are debugging the current connection: if so,
89 * it immediately applies the plan and calls back into io_loop() to
90 * create a linear call chain.
93 * #define io_idle() io_debug(io_idle_())
94 * struct io_plan io_idle_(void);
96 struct io_plan io_debug(struct io_plan plan);
99 * io_debug_io - return from function which actually does I/O.
101 * This determines if we are debugging the current connection: if so,
102 * it immediately sets the next function and calls into io_loop() to
103 * create a linear call chain.
107 * static int do_write(int fd, struct io_plan *plan)
109 * ssize_t ret = write(fd, plan->u.write.buf, plan->u.write.len);
111 * return io_debug_io(-1);
113 * plan->u.write.buf += ret;
114 * plan->u.write.len -= ret;
115 * return io_debug_io(plan->u.write.len == 0);
118 int io_debug_io(int ret);
121 * io_plan_no_debug - mark the next plan not to be called immediately.
123 * Most routines which take a plan are about to apply it to the current
124 * connection. We (ab)use this pattern for debugging: as soon as such a
125 * plan is created it is called, to create a linear call chain.
127 * Some routines, like io_break(), io_duplex() and io_wake() take an
128 * io_plan, but they must not be applied immediately to the current
129 * connection, so we call this first.
132 * #define io_break(ret, plan) (io_plan_no_debug(), io_break_((ret), (plan)))
133 * struct io_plan io_break_(void *ret, struct io_plan plan);
135 #define io_plan_no_debug() ((io_plan_nodebug = true))
137 extern bool io_plan_nodebug;
139 static inline struct io_plan io_debug(struct io_plan plan)
143 static inline int io_debug_io(int ret)
147 #define io_plan_no_debug() (void)0
150 #endif /* CCAN_IO_PLAN_H */