struct io_conn;
/**
- * struct io_plan - a plan of what I/O to do.
- * @pollflag: POLLIN or POLLOUT.
- * @io: function to call when fd is available for @pollflag.
- * @next: function to call after @io returns true.
- * @next_arg: argument to @next.
- * @u: scratch area for I/O.
- *
- * When the fd is POLLIN or POLLOUT (according to @pollflag), @io is
- * called. If it returns -1, io_close() becomed the new plan (and errno
- * is saved). If it returns 1, @next is called, otherwise @io is
- * called again when @pollflag is available.
- *
- * You can use this to write your own io_plan functions.
+ * union io_plan_union - type for struct io_plan read/write fns.
*/
-struct io_plan {
- int pollflag;
- /* Only NULL if idle. */
- int (*io)(int fd, struct io_plan *plan);
- /* Only NULL if closing. */
- struct io_plan (*next)(struct io_conn *, void *arg);
- void *next_arg;
-
- union {
- struct {
- char *buf;
- size_t len;
- } read;
- struct {
- const char *buf;
- size_t len;
- } write;
- struct {
- char *buf;
- size_t *lenp;
- } readpart;
- struct {
- const char *buf;
- size_t *lenp;
- } writepart;
- struct {
- int saved_errno;
- } close;
- struct {
- void *p;
- size_t len;
- } ptr_len;
- struct {
- void *p1;
- void *p2;
- } ptr_ptr;
- struct {
- size_t len1;
- size_t len2;
- } len_len;
- } u;
+union io_plan_union {
+ char *cp;
+ void *vp;
+ const void *const_vp;
+ size_t s;
+ char c[sizeof(size_t)];
};
-#ifdef DEBUG
/**
- * io_debug_conn - routine to select connection(s) to debug.
- *
- * If this is set, the routine should return true if the connection is a
- * debugging candidate. If so, the callchain for I/O operations on this
- * connection will be linear, for easier use of a debugger.
+ * struct io_plan_arg - scratch space for struct io_plan read/write fns.
*/
-extern bool (*io_debug_conn)(struct io_conn *conn);
+struct io_plan_arg {
+ union io_plan_union u1, u2;
+};
-/**
- * io_debug - if we're debugging the current connection, call immediately.
- *
- * This determines if we are debugging the current connection: if so,
- * it immediately applies the plan and calls back into io_loop() to
- * create a linear call chain.
- */
-struct io_plan io_debug(struct io_plan plan);
+enum io_direction {
+ IO_IN,
+ IO_OUT
+};
/**
- * io_debug_io - return from function which actually does I/O.
+ * io_plan_arg - get a conn's io_plan_arg for a given direction.
+ * @conn: the connection.
+ * @dir: IO_IN or IO_OUT.
+ *
+ * This is how an io helper gets scratch space to store into; you must call
+ * io_set_plan() when you've initialized it.
+ *
+ * Example:
+ * #include <ccan/io/io_plan.h>
+ *
+ * // Simple helper to read a single char.
+ * static int do_readchar(int fd, struct io_plan_arg *arg)
+ * {
+ * return read(fd, arg->u1.cp, 1) <= 0 ? -1 : 1;
+ * }
*
- * This determines if we are debugging the current connection: if so,
- * it immediately sets the next function and calls into io_loop() to
- * create a linear call chain.
+ * static struct io_plan *io_read_char_(struct io_conn *conn, char *in,
+ * struct io_plan *(*next)(struct io_conn*,void*),
+ * void *next_arg)
+ * {
+ * struct io_plan_arg *arg = io_plan_arg(conn, IO_IN);
+ *
+ * // Store information we need in the plan unions u1 and u2.
+ * arg->u1.cp = in;
+ *
+ * return io_set_plan(conn, IO_IN, do_readchar, next, next_arg);
+ * }
*/
-int io_debug_io(int ret);
+struct io_plan_arg *io_plan_arg(struct io_conn *conn, enum io_direction dir);
/**
- * io_plan_no_debug - mark the next plan not to be called immediately.
+ * io_set_plan - set a conn's io_plan.
+ * @conn: the connection.
+ * @dir: IO_IN or IO_OUT.
+ * @io: the IO function to call when the fd is ready.
+ * @next: the next callback when @io returns 1.
+ * @next_arg: the argument to @next.
*
- * Most routines which take a plan are about to apply it to the current
- * connection. We (ab)use this pattern for debugging: as soon as such a
- * plan is created it is called, to create a linear call chain.
+ * If @conn has debug set, the io function will be called immediately,
+ * so it's important that this be the last thing in your function!
*
- * Some routines, like io_break(), io_duplex() and io_wake() take an
- * io_plan, but they must not be applied immediately to the current
- * connection, so we call this first.
+ * See also:
+ * io_get_plan_arg()
*/
-#define io_plan_no_debug() ((io_plan_nodebug = true))
-
-extern bool io_plan_nodebug;
-#else
-static inline struct io_plan io_debug(struct io_plan plan)
-{
- return plan;
-}
-static inline int io_debug_io(int ret)
-{
- return ret;
-}
-#define io_plan_no_debug() (void)0
-#endif
-
+struct io_plan *io_set_plan(struct io_conn *conn, enum io_direction dir,
+ int (*io)(int fd, struct io_plan_arg *arg),
+ struct io_plan *(*next)(struct io_conn *, void *),
+ void *next_arg);
#endif /* CCAN_IO_PLAN_H */
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