X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Fio%2Fio.h;h=bcdb11fdd0e0c1f1e9a08aac55a13e0afe888d92;hp=8199bda9802050f747440f66ec1da97f987fcb47;hb=12ab811533406e22b78ce8b227474f1056375ae4;hpb=3a7b8a8a8081ebbb6457527de376dec6264bc381

diff --git a/ccan/io/io.h b/ccan/io/io.h
index 8199bda9..bcdb11fd 100644
--- a/ccan/io/io.h
+++ b/ccan/io/io.h
@@ -5,76 +5,30 @@
 #include <ccan/time/time.h>
 #include <stdbool.h>
 #include <unistd.h>
-
-struct io_conn;
-
-/**
- * struct io_plan - returned from a setup function.
- *
- * A plan of what IO to do, when.
- */
-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 {
-			void *p;
-			size_t len;
-		} ptr_len;
-		struct {
-			void *p1;
-			void *p2;
-		} ptr_ptr;
-		struct {
-			size_t len1;
-			size_t len2;
-		} len_len;
-	} u;
-};
-
-#ifdef DEBUG
-extern bool io_plan_for_other;
-extern bool (*io_debug)(struct io_conn *conn);
-#define io_plan_other() ((io_plan_for_other = true))
-void io_plan_debug(struct io_plan *plan);
-#else
-#define io_plan_other() (void)0
-static inline void io_plan_debug(struct io_plan *plan) { }
-#endif
+#include "io_plan.h"
 
 /**
  * io_new_conn - create a new connection.
  * @fd: the file descriptor.
- * @plan: the first I/O function.
+ * @plan: the first I/O to perform.
  *
  * This creates a connection which owns @fd.  @plan will be called on the
  * next io_loop().
  *
  * Returns NULL on error (and sets errno).
+ *
+ * Example:
+ *	int fd[2];
+ *	struct io_conn *conn;
+ *
+ *	pipe(fd);
+ *	// Plan is to close the fd immediately.
+ *	conn = io_new_conn(fd[0], io_close());
+ *	if (!conn)
+ *		exit(1);
  */
 #define io_new_conn(fd, plan)				\
-	(io_plan_other(), io_new_conn_((fd), (plan)))
+	(io_plan_no_debug(), io_new_conn_((fd), (plan)))
 struct io_conn *io_new_conn_(int fd, struct io_plan plan);
 
 /**
@@ -84,7 +38,17 @@ struct io_conn *io_new_conn_(int fd, struct io_plan plan);
  * @arg: the argument to @finish.
  *
  * @finish will be called when an I/O operation fails, or you call
- * io_close() on the connection.
+ * io_close() on the connection.  errno will be set to the value
+ * after the failed I/O, or at the call to io_close().
+ *
+ * Example:
+ * static void finish(struct io_conn *conn, void *unused)
+ * {
+ *	// errno is not 0 after success, so this is a bit useless.
+ *	printf("Conn %p closed with errno %i\n", conn, errno);
+ * }
+ * ...
+ *	io_set_finish(conn, finish, NULL);
  */
 #define io_set_finish(conn, finish, arg)				\
 	io_set_finish_((conn),						\
@@ -105,6 +69,50 @@ void io_set_finish_(struct io_conn *conn,
  * When @fd becomes readable, we accept() and pass that fd to init().
  *
  * Returns NULL on error (and sets errno).
+ *
+ * Example:
+ * #include <sys/types.h>
+ * #include <sys/socket.h>
+ * #include <netdb.h>
+ *
+ * static void start_conn(int fd, char *msg)
+ * {
+ *	printf("%s fd %i\n", msg, fd);
+ *	close(fd);
+ * }
+ *
+ * // Set up a listening socket, return it.
+ * static struct io_listener *do_listen(const char *port)
+ * {
+ *	struct addrinfo *addrinfo, hints;
+ *	int fd, on = 1;
+ *
+ *	memset(&hints, 0, sizeof(hints));
+ *	hints.ai_family = AF_UNSPEC;
+ *	hints.ai_socktype = SOCK_STREAM;
+ *	hints.ai_flags = AI_PASSIVE;
+ *	hints.ai_protocol = 0;
+ *
+ *	if (getaddrinfo(NULL, port, &hints, &addrinfo) != 0)
+ *		return NULL;
+ *
+ *	fd = socket(addrinfo->ai_family, addrinfo->ai_socktype,
+ *		    addrinfo->ai_protocol);
+ *	if (fd < 0)
+ *		return NULL;
+ *
+ *	freeaddrinfo(addrinfo);
+ *	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+ *	if (bind(fd, addrinfo->ai_addr, addrinfo->ai_addrlen) != 0) {
+ *		close(fd);
+ *		return NULL;
+ *	}
+ *	if (listen(fd, 1) != 0) {
+ *		close(fd);
+ *		return NULL;
+ *	}
+ *	return io_new_listener(fd, start_conn, (char *)"Got one!");
+ * }
  */
 #define io_new_listener(fd, init, arg)					\
 	io_new_listener_((fd),						\
@@ -121,113 +129,255 @@ struct io_listener *io_new_listener_(int fd,
  * @listener: the listener returned from io_new_listener.
  *
  * This closes the fd and frees @listener.
+ *
+ * Example:
+ * ...
+ *	struct io_listener *l = do_listen("8111");
+ *	if (l) {
+ *		io_loop();
+ *		io_close_listener(l);
+ *	}
  */
 void io_close_listener(struct io_listener *listener);
 
 /**
- * io_write - queue data to be written.
+ * io_write - plan to write data.
  * @data: the data buffer.
  * @len: the length to write.
  * @cb: function to call once it's done.
  * @arg: @cb argument
  *
- * This will queue the data buffer for writing.  Once it's all
+ * This creates a plan write out a data buffer.  Once it's all
  * written, the @cb function will be called: on an error, the finish
  * function is called instead.
  *
  * Note that the I/O may actually be done immediately.
+ *
+ * Example:
+ * static void start_conn_with_write(int fd, const char *msg)
+ * {
+ *	// Write message, then close.
+ *	io_new_conn(fd, io_write(msg, strlen(msg), io_close_cb, NULL));
+ * }
  */
 #define io_write(data, len, cb, arg)					\
-	io_write_((data), (len),					\
-		  typesafe_cb_preargs(struct io_plan, void *,		\
-				      (cb), (arg), struct io_conn *),	\
-		  (arg))
+	io_debug(io_write_((data), (len),				\
+			   typesafe_cb_preargs(struct io_plan, void *,	\
+					       (cb), (arg), struct io_conn *), \
+			   (arg)))
 struct io_plan io_write_(const void *data, size_t len,
 			 struct io_plan (*cb)(struct io_conn *, void *),
 			 void *arg);
 
 /**
- * io_read - queue buffer to be read.
+ * io_read - plan to read data.
  * @data: the data buffer.
  * @len: the length to read.
  * @cb: function to call once it's done.
  * @arg: @cb argument
  *
- * This will queue the data buffer for reading.  Once it's all read,
- * the @cb function will be called: on an error, the finish function
- * is called instead.
+ * This creates a plan to read data into a buffer.  Once it's all
+ * read, the @cb function will be called: on an error, the finish
+ * function is called instead.
  *
  * Note that the I/O may actually be done immediately.
+ *
+ * Example:
+ * static void start_conn_with_read(int fd, char msg[12])
+ * {
+ *	// Read message, then close.
+ *	io_new_conn(fd, io_read(msg, 12, io_close_cb, NULL));
+ * }
  */
 #define io_read(data, len, cb, arg)					\
-	io_read_((data), (len),						\
-		 typesafe_cb_preargs(struct io_plan, void *,		\
-				     (cb), (arg), struct io_conn *),	\
-		 (arg))
+	io_debug(io_read_((data), (len),				\
+			  typesafe_cb_preargs(struct io_plan, void *,	\
+					      (cb), (arg), struct io_conn *), \
+			  (arg)))
 struct io_plan io_read_(void *data, size_t len,
 			struct io_plan (*cb)(struct io_conn *, void *),
 			void *arg);
 
 
 /**
- * io_read_partial - queue buffer to be read (partial OK).
+ * io_read_partial - plan to read some data.
  * @data: the data buffer.
  * @len: the maximum length to read, set to the length actually read.
  * @cb: function to call once it's done.
  * @arg: @cb argument
  *
- * This will queue the data buffer for reading.  Once any data is
+ * This creates a plan to read data into a buffer.  Once any data is
  * read, @len is updated and the @cb function will be called: on an
  * error, the finish function is called instead.
  *
  * Note that the I/O may actually be done immediately.
+ *
+ * Example:
+ * struct buf {
+ *	size_t len;
+ *	char buf[12];
+ * };
+ *
+ * static struct io_plan dump_and_close(struct io_conn *conn, struct buf *b)
+ * {
+ *	printf("Partial read: '%*s'\n", (int)b->len, b->buf);
+ *	free(b);
+ *	return io_close();
+ * }
+ *
+ * static void start_conn_with_part_read(int fd, void *unused)
+ * {
+ *	struct buf *b = malloc(sizeof(*b));
+ *
+ *	// Read message, then dump and close.
+ *	b->len = sizeof(b->buf);
+ *	io_new_conn(fd, io_read_partial(b->buf, &b->len, dump_and_close, b));
+ * }
  */
 #define io_read_partial(data, len, cb, arg)				\
-	io_read_partial_((data), (len),					\
-			 typesafe_cb_preargs(struct io_plan, void *,	\
-					     (cb), (arg), struct io_conn *), \
-			 (arg))
+	io_debug(io_read_partial_((data), (len),			\
+				  typesafe_cb_preargs(struct io_plan, void *, \
+						      (cb), (arg),	\
+						      struct io_conn *), \
+				  (arg)))
 struct io_plan io_read_partial_(void *data, size_t *len,
 				struct io_plan (*cb)(struct io_conn *, void *),
 				void *arg);
 
 /**
- * io_write_partial - queue data to be written (partial OK).
+ * io_write_partial - plan to write some data.
  * @data: the data buffer.
  * @len: the maximum length to write, set to the length actually written.
  * @cb: function to call once it's done.
  * @arg: @cb argument
  *
- * This will queue the data buffer for writing.  Once any data is
+ * This creates a plan to write data from a buffer.   Once any data is
  * written, @len is updated and the @cb function will be called: on an
  * error, the finish function is called instead.
  *
  * Note that the I/O may actually be done immediately.
+ *
+ * Example:
+ * struct buf {
+ *	size_t len;
+ *	char buf[12];
+ * };
+ *
+ * static struct io_plan show_remainder(struct io_conn *conn, struct buf *b)
+ * {
+ *	printf("Only wrote: '%*s'\n", (int)b->len, b->buf);
+ *	free(b);
+ *	return io_close();
+ * }
+ *
+ * static void start_conn_with_part_read(int fd, void *unused)
+ * {
+ *	struct buf *b = malloc(sizeof(*b));
+ *
+ *	// Write message, then dump and close.
+ *	b->len = sizeof(b->buf);
+ *	strcpy(b->buf, "Hello world");
+ *	io_new_conn(fd, io_write_partial(b->buf, &b->len, show_remainder, b));
+ * }
  */
 #define io_write_partial(data, len, cb, arg)				\
-	io_write_partial_((data), (len),				\
-			  typesafe_cb_preargs(struct io_plan, void *,	\
-					      (cb), (arg), struct io_conn *), \
-			  (arg))
+	io_debug(io_write_partial_((data), (len),			\
+				   typesafe_cb_preargs(struct io_plan, void *, \
+						       (cb), (arg),	\
+						       struct io_conn *), \
+				   (arg)))
 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_idle - explicitly note that this connection will do nothing.
+ * io_connect - plan to connect to a listening socket.
+ * @fd: file descriptor.
+ * @addr: where to connect.
+ * @cb: function to call once it's done.
+ * @arg: @cb argument
+ *
+ * This initiates a connection, and creates a plan for
+ * (asynchronously).  completing it.  Once complete, @len is updated
+ * and the @cb function will be called: on an error, the finish
+ * function is called instead.
  *
- * This indicates the connection is idle: some other function will
- * later call io_read/io_write etc. (or io_close) on it, in which case
- * it will do that.
+ * Note that the connect may actually be done immediately.
+ *
+ * Example:
+ * #include <sys/types.h>
+ * #include <sys/socket.h>
+ * #include <netdb.h>
+ *
+ * // Write, then close socket.
+ * static struct io_plan start_write(struct io_conn *conn, void *unused)
+ * {
+ *	return io_write("hello", 5, io_close_cb, NULL);
+ * }
+ *
+ * ...
+ *
+ *	int fd;
+ *	struct addrinfo *addrinfo;
+ *
+ *	fd = socket(AF_INET, SOCK_STREAM, 0);
+ *	getaddrinfo("localhost", "8111", NULL, &addrinfo);
+ *	io_new_conn(fd, io_connect(fd, addrinfo, start_write, NULL));
  */
-struct io_plan io_idle(void);
+struct addrinfo;
+#define io_connect(fd, addr, cb, arg)					\
+	io_debug(io_connect_((fd), (addr),				\
+			     typesafe_cb_preargs(struct io_plan, void *, \
+						 (cb), (arg),		\
+						 struct io_conn *),	\
+			     (arg)))
+struct io_plan io_connect_(int fd, const struct addrinfo *addr,
+			   struct io_plan (*cb)(struct io_conn *, void*),
+			   void *arg);
 
 /**
- * io_timeout - set timeout function if the callback doesn't fire.
+ * io_idle - plan to do nothing.
+ *
+ * This indicates the connection is idle: io_wake() will be called later do
+ * give the connection a new plan.
+ *
+ * Example:
+ *	struct io_conn *sleeper;
+ *	sleeper = io_new_conn(open("/dev/null", O_RDONLY), io_idle());
+ *	if (!sleeper)
+ *		exit(1);
+ */
+#define io_idle() io_debug(io_idle_())
+struct io_plan io_idle_(void);
+
+/**
+ * io_timeout - set timeout function if the callback doesn't complete.
  * @conn: the current connection.
  * @ts: how long until the timeout should be called.
- * @cb to call.
+ * @cb: callback to call.
  * @arg: argument to @cb.
  *
  * If the usual next callback is not called for this connection before @ts,
@@ -236,6 +386,17 @@ struct io_plan io_idle(void);
  *
  * Returns false on allocation failure.  A connection can only have one
  * timeout.
+ *
+ * Example:
+ *	static struct io_plan close_on_timeout(struct io_conn *conn, char *msg)
+ *	{
+ *		printf("%s\n", msg);
+ *		return io_close();
+ *	}
+ *
+ *	...
+ *	io_timeout(sleeper, time_from_msec(100),
+ *		   close_on_timeout, (char *)"Bye!");
  */
 #define io_timeout(conn, ts, fn, arg)					\
 	io_timeout_((conn), (ts),					\
@@ -252,27 +413,62 @@ bool io_timeout_(struct io_conn *conn, struct timespec ts,
  * @plan: the first I/O function to call.
  *
  * Sometimes you want to be able to simultaneously read and write on a
- * single fd, but io forces a linear call sequence.  The solition is
+ * single fd, but io forces a linear call sequence.  The solution is
  * to have two connections for the same fd, and use one for read
  * operations and one for write.
  *
  * You must io_close() both of them to close the fd.
+ *
+ * Example:
+ *	static void setup_read_write(int fd,
+ *				     char greet_in[5], const char greet_out[5])
+ *	{
+ *		struct io_conn *writer, *reader;
+ *
+ *		// Read their greeting and send ours at the same time.
+ *		writer = io_new_conn(fd,
+ *				     io_write(greet_out, 5, io_close_cb, NULL));
+ *		reader = io_duplex(writer,
+ *				     io_read(greet_in, 5, io_close_cb, NULL));
+ *		if (!reader || !writer)
+ *			exit(1);
+ *	}
  */
 #define io_duplex(conn, plan)				\
-	(io_plan_other(), io_duplex_((conn), (plan)))
-
+	(io_plan_no_debug(), io_duplex_((conn), (plan)))
 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 function for @conn.
+ * @plan: the next I/O plan for @conn.
+ *
+ * This makes @conn ready to do I/O the next time around the io_loop().
  *
- * This makes @conn do I/O the next time around the io_loop().
+ * Example:
+ *	struct io_conn *sleeper;
+ *	sleeper = io_new_conn(open("/dev/null", O_RDONLY), io_idle());
+ *
+ *	io_wake(sleeper, io_write("junk", 4, io_close_cb, NULL));
  */
-#define io_wake(conn, plan) (io_plan_other(), io_wake_((conn), (plan)))
+#define io_wake(conn, plan) (io_plan_no_debug(), io_wake_((conn), (plan)))
 void io_wake_(struct io_conn *conn, struct io_plan plan);
 
+/**
+ * io_is_idle - is a connection idle?
+ *
+ * This can be useful for complex protocols, eg. where you want a connection
+ * to send something, so you queue it and wake it if it's idle.
+ *
+ * Example:
+ *	struct io_conn *sleeper;
+ *	sleeper = io_new_conn(open("/dev/null", O_RDONLY), io_idle());
+ *
+ *	assert(io_is_idle(sleeper));
+ *	io_wake(sleeper, io_write("junk", 4, io_close_cb, NULL));
+ */
+bool io_is_idle(const struct io_conn *conn);
+
 /**
  * io_break - return from io_loop()
  * @ret: non-NULL value to return from io_loop().
@@ -283,8 +479,14 @@ void io_wake_(struct io_conn *conn, struct io_plan plan);
  * finish callbacks called, then io_loop() with return with @ret.
  *
  * If io_loop() is called again, then @plan will be carried out.
+ *
+ * Example:
+ *	static struct io_plan fail_on_timeout(struct io_conn *conn, char *msg)
+ *	{
+ *		return io_break(msg, io_close());
+ *	}
  */
-#define io_break(ret, plan) (io_plan_other(), io_break_((ret), (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);
 
 /* FIXME: io_recvfrom/io_sendto */
@@ -293,8 +495,16 @@ struct io_plan io_break_(void *ret, struct io_plan plan);
  * io_close - plan to close a connection.
  *
  * On return to io_loop, the connection will be closed.
+ *
+ * Example:
+ * static struct io_plan close_on_timeout(struct io_conn *conn, const char *msg)
+ * {
+ *	printf("closing: %s\n", msg);
+ *	return io_close();
+ * }
  */
-struct io_plan io_close(void);
+#define io_close() io_debug(io_close_())
+struct io_plan io_close_(void);
 
 /**
  * io_close_cb - helper callback to close a connection.
@@ -302,14 +512,59 @@ struct io_plan io_close(void);
  *
  * This schedules a connection to be closed; designed to be used as
  * a callback function.
+ *
+ * Example:
+ *	#define close_on_timeout io_close_cb
  */
 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.
  *
  * This is the core loop; it exits with the io_break() arg, or NULL if
  * all connections and listeners are closed.
+ *
+ * Example:
+ *	io_loop();
  */
 void *io_loop(void);
+
+/**
+ * io_conn_fd - get the fd from a connection.
+ * @conn: the connection.
+ *
+ * Sometimes useful, eg for getsockname().
+ */
+int io_conn_fd(const struct io_conn *conn);
+
+/**
+ * io_set_alloc - set alloc/realloc/free function for io to use.
+ * @allocfn: allocator function
+ * @reallocfn: reallocator function, ptr may be NULL, size never 0.
+ * @freefn: free function
+ *
+ * By default io uses malloc/realloc/free, and returns NULL if they fail.
+ * You can set your own variants here.
+ */
+void io_set_alloc(void *(*allocfn)(size_t size),
+		  void *(*reallocfn)(void *ptr, size_t size),
+		  void (*freefn)(void *ptr));
 #endif /* CCAN_IO_H */