X-Git-Url: http://git.ozlabs.org/?a=blobdiff_plain;f=ccan%2Fio%2Fio.h;h=1cf9d609973066c04c696f3412fd735ca241bf5d;hb=fe6805a9cfb6f880dc0b161b647a8d97123ad2a3;hp=165ff6f63361d395db25a4706d21eec51b5bbb1b;hpb=94dd4c2bddd0dc080ad5b85465fa3f45f486967a;p=ccan

diff --git a/ccan/io/io.h b/ccan/io/io.h
index 165ff6f6..1cf9d609 100644
--- a/ccan/io/io.h
+++ b/ccan/io/io.h
@@ -362,6 +362,27 @@ struct io_plan *io_always_(struct io_conn *conn,
 			   struct io_plan *(*next)(struct io_conn *, void *),
 			   void *arg);
 
+/**
+ * io_out_always - output plan to immediately call next callback
+ * @conn: the connection that plan is for.
+ * @next: function to call.
+ * @arg: @next argument
+ *
+ * This is a variant of io_always() which uses the output plan; it only
+ * matters if you are using io_duplex, and thus have two plans running at
+ * once.
+ */
+#define io_out_always(conn, next, arg)					\
+	io_out_always_((conn), typesafe_cb_preargs(struct io_plan *, void *, \
+						   (next), (arg),	\
+						   struct io_conn *),	\
+		       (arg))
+
+struct io_plan *io_out_always_(struct io_conn *conn,
+			       struct io_plan *(*next)(struct io_conn *,
+						       void *),
+			       void *arg);
+
 /**
  * io_connect - create an asynchronous connection to a listening socket.
  * @conn: the connection that plan is for.
@@ -418,11 +439,32 @@ struct io_plan *io_connect_(struct io_conn *conn, const struct addrinfo *addr,
  *
  * Note that if either plan closes the connection, it will be closed.
  *
- * Note that if one plan is io_wait or io_always, that causes a problem:
- * they look at the input and output plan slots to figure out which to
- * use, but if the other plan hasn't been evaluated yet, that will fail.
- * In this case, you'll need to ensure the other plan is evaluated first,
- * eg. "struct io_plan *r = io_read(...); return io_duplex(r, io_always(...))"
+ * Example:
+ * struct buf {
+ *	char in[100];
+ *	char out[100];
+ * };
+ *
+ * static struct io_plan *read_and_write(struct io_conn *conn, struct buf *b)
+ * {
+ *	return io_duplex(conn,
+ *			 io_read(conn, b->in, sizeof(b->in), io_close_cb, b),
+ *			 io_write(conn, b->out, sizeof(b->out), io_close_cb,b));
+ * }
+ */
+#define io_duplex(conn, in_plan, out_plan) \
+	(io_duplex_prepare(conn), io_duplex_(in_plan, out_plan))
+
+struct io_plan *io_duplex_(struct io_plan *in_plan, struct io_plan *out_plan);
+void io_duplex_prepare(struct io_conn *conn);
+
+/**
+ * io_halfclose - close half of an io_duplex connection.
+ * @conn: the connection that plan is for.
+ *
+ * It's common to want to close a duplex connection after both input and
+ * output plans have completed.  If either calls io_close() the connection
+ * closes immediately.  Instead, io_halfclose() needs to be called twice.
  *
  * Example:
  * struct buf {
@@ -430,13 +472,19 @@ struct io_plan *io_connect_(struct io_conn *conn, const struct addrinfo *addr,
  *	char out[100];
  * };
  *
+ * static struct io_plan *finish(struct io_conn *conn, struct buf *b)
+ * {
+ *	return io_halfclose(conn);
+ * }
+ *
  * static struct io_plan *read_and_write(struct io_conn *conn, struct buf *b)
  * {
- *	return io_duplex(io_read(conn, b->in, sizeof(b->in), io_close_cb, b),
- *			 io_write(conn, b->out, sizeof(b->out), io_close_cb, b));
+ *	return io_duplex(conn,
+ *			 io_read(conn, b->in, sizeof(b->in), finish, b),
+ *			 io_write(conn, b->out, sizeof(b->out), finish, b));
  * }
  */
-struct io_plan *io_duplex(struct io_plan *in_plan, struct io_plan *out_plan);
+struct io_plan *io_halfclose(struct io_conn *conn);
 
 /**
  * io_wait - leave a plan idle until something wakes us.
@@ -468,6 +516,30 @@ struct io_plan *io_wait_(struct io_conn *conn,
 			 void *arg);
 
 
+/**
+ * io_out_wait - leave the output plan idle until something wakes us.
+ * @conn: the connection that plan is for.
+ * @waitaddr: the address to wait on.
+ * @next: function to call after waiting.
+ * @arg: @next argument
+ *
+ * io_wait() makes the input plan idle: if you're not using io_duplex it
+ * doesn't matter which plan is waiting.  Otherwise, you may need to use
+ * io_out_wait() instead, to specify explicitly that the output plan is
+ * waiting.
+ */
+#define io_out_wait(conn, waitaddr, next, arg)				\
+	io_out_wait_((conn), (waitaddr),				\
+		     typesafe_cb_preargs(struct io_plan *, void *,	\
+					 (next), (arg),			\
+					 struct io_conn *),		\
+		     (arg))
+
+struct io_plan *io_out_wait_(struct io_conn *conn,
+			     const void *wait,
+			     struct io_plan *(*next)(struct io_conn *, void *),
+			     void *arg);
+
 /**
  * io_wake - wake up any connections waiting on @wait
  * @waitaddr: the address to trigger.
@@ -575,4 +647,38 @@ void *io_loop(struct timers *timers, struct list_head *expired);
  * Sometimes useful, eg for getsockname().
  */
 int io_conn_fd(const struct io_conn *conn);
+
+/**
+ * io_set_debug - set synchronous mode on a connection.
+ * @conn: the connection.
+ * @debug: whether to enable or disable debug.
+ *
+ * Once @debug is true on a connection, all I/O is done synchronously
+ * as soon as it is set, until it is unset or @conn is closed.  This
+ * makes it easy to debug what's happening with a connection, but note
+ * that other connections are starved while this is being done.
+ *
+ * See also: io_debug_complete()
+ *
+ * Example:
+ * // Dumb init function to set debug and tell conn to close.
+ * static struct io_plan *conn_init(struct io_conn *conn, const char *msg)
+ * {
+ *	io_set_debug(conn, true);
+ *	return io_close(conn);
+ * }
+ */
+void io_set_debug(struct io_conn *conn, bool debug);
+
+/**
+ * io_debug_complete - empty function called when conn is closing/waiting.
+ * @conn: the connection.
+ *
+ * This is for putting a breakpoint onto, when debugging.  It is called
+ * when a conn with io_set_debug() true can no longer be synchronous:
+ * 1) It is io_close()'d
+ * 2) It enters io_wait() (sychronous debug will resume after io_wake())
+ * 3) io_break() is called (sychronous debug will resume after io_loop())
+ */
+void io_debug_complete(struct io_conn *conn);
 #endif /* CCAN_IO_H */