X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fio%2Fio.h;h=505c4c70a3fd5bc3f183a3927a2595d9776f9d2b;hb=f7ab2c65d40839a327e50876dc2708ab7b11aa52;hp=0318aef300873fa71104e0a2b630ad28e93e7065;hpb=83d4e1285dec87fa54043377eafd1b3bf9b0c53f;p=ccan

diff --git a/ccan/io/io.h b/ccan/io/io.h
index 0318aef3..505c4c70 100644
--- a/ccan/io/io.h
+++ b/ccan/io/io.h
@@ -39,7 +39,8 @@ struct io_conn *io_new_conn_(int fd, struct io_plan plan);
  *
  * @finish will be called when an I/O operation fails, or you call
  * io_close() on the connection.  errno will be set to the value
- * after the failed I/O, or at the call to io_close().
+ * after the failed I/O, or at the call to io_close().  The fd
+ * will be closed (unless a duplex) before @finish is called.
  *
  * Example:
  * static void finish(struct io_conn *conn, void *unused)
@@ -290,6 +291,30 @@ struct io_plan io_write_partial_(const void *data, size_t *len,
 				 struct io_plan (*cb)(struct io_conn *, void*),
 				 void *arg);
 
+/**
+ * io_always - plan to immediately call next callback.
+ * @cb: function to call.
+ * @arg: @cb argument
+ *
+ * Sometimes it's neater to plan a callback rather than call it directly;
+ * for example, if you only need to read data for one path and not another.
+ *
+ * Example:
+ * static void start_conn_with_nothing(int fd)
+ * {
+ *	// Silly example: close on next time around loop.
+ *	io_new_conn(fd, io_always(io_close_cb, NULL));
+ * }
+ */
+#define io_always(cb, arg)						\
+	io_debug(io_always_(typesafe_cb_preargs(struct io_plan, void *,	\
+						(cb), (arg),		\
+						struct io_conn *),	\
+			    (arg)))
+struct io_plan io_always_(struct io_plan (*cb)(struct io_conn *, void *),
+			  void *arg);
+
+
 /**
  * io_connect - plan to connect to a listening socket.
  * @fd: file descriptor.
@@ -336,19 +361,32 @@ struct io_plan io_connect_(int fd, const struct addrinfo *addr,
 			   void *arg);
 
 /**
- * io_idle - plan to do nothing.
+ * io_wait - plan to wait for something.
+ * @wait: the address to wait on.
+ * @cb: function to call after waiting.
+ * @arg: @cb argument
  *
- * This indicates the connection is idle: io_wake() will be called later do
- * give the connection a new plan.
+ * This indicates the connection is idle: io_wake() will be called later to
+ * restart the connection.
  *
  * Example:
  *	struct io_conn *sleeper;
- *	sleeper = io_new_conn(open("/dev/null", O_RDONLY), io_idle());
+ *	unsigned int counter = 0;
+ *	sleeper = io_new_conn(open("/dev/null", O_RDONLY),
+ *			      io_wait(&counter, io_close_cb, NULL));
  *	if (!sleeper)
  *		exit(1);
  */
-#define io_idle() io_debug(io_idle_())
-struct io_plan io_idle_(void);
+#define io_wait(wait, cb, arg)						\
+	io_debug(io_wait_(wait,						\
+			  typesafe_cb_preargs(struct io_plan, void *,	\
+					      (cb), (arg),		\
+					      struct io_conn *),	\
+			  (arg)))
+
+struct io_plan io_wait_(const void *wait,
+			struct io_plan (*cb)(struct io_conn *, void *),
+			void *arg);
 
 /**
  * io_timeout - set timeout function if the callback doesn't complete.
@@ -394,7 +432,7 @@ bool io_timeout_(struct io_conn *conn, struct timespec ts,
  * to have two connections for the same fd, and use one for read
  * operations and one for write.
  *
- * Returning io_close() on one will close both fds!
+ * You must io_close() both of them to close the fd.
  *
  * Example:
  *	static void setup_read_write(int fd,
@@ -416,20 +454,18 @@ bool io_timeout_(struct io_conn *conn, struct timespec ts,
 struct io_conn *io_duplex_(struct io_conn *conn, struct io_plan plan);
 
 /**
- * io_wake - wake up an idle connection.
- * @conn: an idle connection.
- * @plan: the next I/O plan for @conn.
- *
- * This makes @conn ready to do I/O the next time around the io_loop().
+ * io_wake - wake up any connections waiting on @wait
+ * @wait: the address to trigger.
  *
  * Example:
- *	struct io_conn *sleeper;
- *	sleeper = io_new_conn(open("/dev/null", O_RDONLY), io_idle());
+ *	unsigned int wait;
  *
- *	io_wake(sleeper, io_write("junk", 4, io_close_cb, NULL));
+ *	io_new_conn(open("/dev/null", O_RDONLY),
+ *		   io_wait(&wait, io_close_cb, NULL));
+ *
+ *	io_wake(&wait);
  */
-#define io_wake(conn, plan) (io_plan_no_debug(), io_wake_((conn), (plan)))
-void io_wake_(struct io_conn *conn, struct io_plan plan);
+void io_wake(const void *wait);
 
 /**
  * io_break - return from io_loop()
@@ -451,6 +487,21 @@ void io_wake_(struct io_conn *conn, struct io_plan plan);
 #define io_break(ret, plan) (io_plan_no_debug(), io_break_((ret), (plan)))
 struct io_plan io_break_(void *ret, struct io_plan plan);
 
+/**
+ * io_never - assert if callback is called.
+ *
+ * Sometimes you want to make it clear that a callback should never happen
+ * (eg. for io_break).  This will assert() if called.
+ *
+ * Example:
+ * static struct io_plan break_out(struct io_conn *conn, void *unused)
+ * {
+ *	// We won't ever return from io_break
+ *	return io_break(conn, io_never());
+ * }
+ */
+struct io_plan io_never(void);
+
 /* FIXME: io_recvfrom/io_sendto */
 
 /**
@@ -480,6 +531,24 @@ struct io_plan io_close_(void);
  */
 struct io_plan io_close_cb(struct io_conn *, void *unused);
 
+/**
+ * io_close_other - close different connection next time around the I/O loop.
+ * @conn: the connection to close.
+ *
+ * This is used to force a different connection to close: no more I/O will
+ * happen on @conn, even if it's pending.
+ *
+ * It's a bug to use this on the current connection!
+ *
+ * Example:
+ * static void stop_connection(struct io_conn *conn)
+ * {
+ *	printf("forcing stop on connection\n");
+ *	io_close_other(conn);
+ * }
+ */
+void io_close_other(struct io_conn *conn);
+
 /**
  * io_loop - process fds until all closed on io_break.
  *