ccan/io: flatten debug callchain.

Don't call from the plan-construction function, call after it returns.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/io/backend.h

@@ -55,7 +55,7 @@ static inline void set_current(struct io_conn *conn)
 }
 static inline bool doing_debug(void)
 {
-	return io_debug != NULL;
+	return io_debug_conn != NULL;
 }
 #else
 static inline void set_current(struct io_conn *conn)

ccan/io/io.c

@@ -13,42 +13,56 @@
 void *io_loop_return;
 
 #ifdef DEBUG
-bool io_plan_for_other;
+/* Set to skip the next plan. */
+bool io_plan_nodebug;
+/* The current connection to apply plan to. */
 struct io_conn *current;
-bool (*io_debug)(struct io_conn *conn);
+/* User-defined function to select which connection(s) to debug. */
+bool (*io_debug_conn)(struct io_conn *conn);
+/* Set when we wake up an connection we are debugging. */
 bool io_debug_wakeup;
 
-void io_plan_debug(struct io_plan *plan)
+struct io_plan io_debug(struct io_plan plan)
 {
-	if (io_plan_for_other) {
-		io_plan_for_other = false;
-		return;
+	if (io_plan_nodebug) {
+		io_plan_nodebug = false;
+		return plan;
 	}
 
-	if (!io_debug || !current)
-		return;
+	if (!io_debug_conn || !current)
+		return plan;
 
-	if (!io_debug(current) && !io_debug_wakeup)
-		return;
+	if (!io_debug_conn(current) && !io_debug_wakeup)
+		return plan;
 
 	io_debug_wakeup = false;
-	current->plan = *plan;
+	current->plan = plan;
 	backend_plan_changed(current);
 
 	/* Call back into the loop immediately. */
 	io_loop_return = io_loop();
+	return plan;
 }
 
 static void debug_io_wake(struct io_conn *conn)
 {
 	/* We want linear if we wake a debugged connection, too. */
-	if (io_debug && io_debug(conn))
+	if (io_debug_conn && io_debug_conn(conn))
 		io_debug_wakeup = true;
 }
+
+/* Counterpart to io_plan_no_debug(), called in macros in io.h */
+static void io_plan_debug_again(void)
+{
+	io_plan_nodebug = false;
+}
 #else
 static void debug_io_wake(struct io_conn *conn)
 {
 }
+static void io_plan_debug_again(void)
+{
+}
 #endif
 
 struct io_listener *io_new_listener_(int fd,
@@ -82,6 +96,8 @@ struct io_conn *io_new_conn_(int fd, struct io_plan plan)
 {
 	struct io_conn *conn = malloc(sizeof(*conn));
 
+	io_plan_debug_again();
+
 	if (!conn)
 		return NULL;
 
@@ -111,6 +127,8 @@ struct io_conn *io_duplex_(struct io_conn *old, struct io_plan plan)
 {
 	struct io_conn *conn;
 
+	io_plan_debug_again();
+
 	assert(!old->duplex);
 
 	conn = malloc(sizeof(*conn));
@@ -177,7 +195,6 @@ struct io_plan io_write_(const void *data, size_t len,
 	plan.next_arg = arg;
 	plan.pollflag = POLLOUT;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 
@@ -207,7 +224,6 @@ struct io_plan io_read_(void *data, size_t len,
 	plan.next_arg = arg;
 	plan.pollflag = POLLIN;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 
@@ -236,7 +252,6 @@ struct io_plan io_read_partial_(void *data, size_t *len,
 	plan.next_arg = arg;
 	plan.pollflag = POLLIN;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 
@@ -265,26 +280,26 @@ struct io_plan io_write_partial_(const void *data, size_t *len,
 	plan.next_arg = arg;
 	plan.pollflag = POLLOUT;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 
-struct io_plan io_idle(void)
+struct io_plan io_idle_(void)
 {
 	struct io_plan plan;
 
 	plan.pollflag = 0;
 	plan.io = NULL;
 	/* Never called (overridden by io_wake), but NULL means closing */
-	plan.next = (void *)io_idle;
+	plan.next = (void *)io_idle_;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 
 void io_wake_(struct io_conn *conn, struct io_plan plan)
 
 {
+	io_plan_debug_again();
+
 	/* It might be closing, but we haven't called its finish() yet. */
 	if (!conn->plan.next)
 		return;
@@ -318,7 +333,7 @@ void io_ready(struct io_conn *conn)
 }
 
 /* Close the connection, we're done. */
-struct io_plan io_close(void)
+struct io_plan io_close_(void)
 {
 	struct io_plan plan;
 
@@ -327,7 +342,6 @@ struct io_plan io_close(void)
 	plan.next = NULL;
 	plan.u.close.saved_errno = errno;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 
@@ -339,6 +353,8 @@ struct io_plan io_close_cb(struct io_conn *conn, void *arg)
 /* Exit the loop, returning this (non-NULL) arg. */
 struct io_plan io_break_(void *ret, struct io_plan plan)
 {
+	io_plan_debug_again();
+
 	assert(ret);
 	io_loop_return = ret;
 

ccan/io/io.h

@@ -18,7 +18,7 @@
  * Returns NULL on error (and sets errno).
  */
 #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);
 
 /**
@@ -83,10 +83,10 @@ void io_close_listener(struct io_listener *listener);
  * Note that the I/O may actually be done immediately.
  */
 #define io_write(data, len, cb, arg)					\
-	io_write_((data), (len),					\
+	io_debug(io_write_((data), (len),				\
 			   typesafe_cb_preargs(struct io_plan, void *,	\
 					       (cb), (arg), struct io_conn *), \
-		  (arg))
+			   (arg)))
 struct io_plan io_write_(const void *data, size_t len,
 			 struct io_plan (*cb)(struct io_conn *, void *),
 			 void *arg);
@@ -105,10 +105,10 @@ struct io_plan io_write_(const void *data, size_t len,
  * Note that the I/O may actually be done immediately.
  */
 #define io_read(data, len, cb, arg)					\
-	io_read_((data), (len),						\
+	io_debug(io_read_((data), (len),				\
 			  typesafe_cb_preargs(struct io_plan, void *,	\
 					      (cb), (arg), struct io_conn *), \
-		 (arg))
+			  (arg)))
 struct io_plan io_read_(void *data, size_t len,
 			struct io_plan (*cb)(struct io_conn *, void *),
 			void *arg);
@@ -128,10 +128,11 @@ struct io_plan io_read_(void *data, size_t len,
  * Note that the I/O may actually be done immediately.
  */
 #define io_read_partial(data, len, cb, arg)				\
-	io_read_partial_((data), (len),					\
+	io_debug(io_read_partial_((data), (len),			\
 				  typesafe_cb_preargs(struct io_plan, void *, \
-					     (cb), (arg), struct io_conn *), \
-			 (arg))
+						      (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);
@@ -150,10 +151,11 @@ struct io_plan io_read_partial_(void *data, size_t *len,
  * Note that the I/O may actually be done immediately.
  */
 #define io_write_partial(data, len, cb, arg)				\
-	io_write_partial_((data), (len),				\
+	io_debug(io_write_partial_((data), (len),			\
 				   typesafe_cb_preargs(struct io_plan, void *, \
-					      (cb), (arg), struct io_conn *), \
-			  (arg))
+						       (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);
@@ -164,7 +166,8 @@ struct io_plan io_write_partial_(const void *data, size_t *len,
  * This indicates the connection is idle: io_wake() will be called later do
  * give the connection a new plan.
  */
-struct io_plan io_idle(void);
+#define io_idle() io_debug(io_idle_())
+struct io_plan io_idle_(void);
 
 /**
  * io_timeout - set timeout function if the callback doesn't complete.
@@ -202,7 +205,7 @@ bool io_timeout_(struct io_conn *conn, struct timespec ts,
  * You must io_close() both of them to close the fd.
  */
 #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);
 
 /**
@@ -212,7 +215,7 @@ struct io_conn *io_duplex_(struct io_conn *conn, struct io_plan plan);
  *
  * This makes @conn ready to do I/O the next time around the io_loop().
  */
-#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);
 
 /**
@@ -226,7 +229,7 @@ void io_wake_(struct io_conn *conn, struct io_plan plan);
  *
  * If io_loop() is called again, then @plan will be carried out.
  */
-#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 */
@@ -236,7 +239,8 @@ struct io_plan io_break_(void *ret, struct io_plan plan);
  *
  * On return to io_loop, the connection will be closed.
  */
-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.

ccan/io/io_plan.h

@@ -63,38 +63,43 @@ struct io_plan {
 
 #ifdef DEBUG
 /**
- * io_debug - routine to select connection(s) to 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.
  */
-extern bool (*io_debug)(struct io_conn *conn);
+extern bool (*io_debug_conn)(struct io_conn *conn);
 
 /**
- * io_plan_other - mark the next plan not being for the current connection
+ * io_debug - if we're debugging the current connection, call immediately.
  *
- * 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.
- *
- * Some routines, like io_break() and io_wake() take an io_plan, but they
- * must not be applied immediately to the current connection, so we call this
- * first.
+ * 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.
  */
-#define io_plan_other() ((io_plan_for_other = true))
+struct io_plan io_debug(struct io_plan plan);
 
 /**
- * io_plan_debug - hook for debugging a plan.
+ * io_plan_no_debug - mark the next plan not to be called immediately.
  *
- * After constructing a plan, call this.  If the current connection is being
- * debugged, then it will be immediately serviced with this plan.
+ * 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.
+ *
+ * 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.
  */
-void io_plan_debug(struct io_plan *plan);
-extern bool io_plan_for_other;
+#define io_plan_no_debug() ((io_plan_nodebug = true))
+
+extern bool io_plan_nodebug;
 #else
-#define io_plan_other() (void)0
-static inline void io_plan_debug(struct io_plan *plan) { }
+static inline struct io_plan io_debug(struct io_plan plan)
+{
+	return plan;
+}
+#define io_plan_no_debug() (void)0
 #endif
 
 #endif /* CCAN_IO_PLAN_H */

ccan/io/test/run-01-start-finish-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-01-start-finish.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-02-read-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-02-read.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-03-readpartial-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-03-readpartial.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-04-writepartial-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-04-writepartial.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-05-write-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-05-write.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-06-idle-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-06-idle.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-07-break-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-07-break.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-08-hangup-on-idle-DEBUG.c

@@ -4,4 +4,4 @@ int real_main(void);
 #include "run-08-hangup-on-idle.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-08-read-after-hangup-DEBUG.c

@@ -4,4 +4,4 @@ int real_main(void);
 #include "run-08-read-after-hangup.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-10-many-DEBUG.c

@@ -9,4 +9,4 @@ static bool debug_one(struct io_conn *conn)
 {
 	return conn == buf[1].reader;
 }
-int main(void) { io_debug = debug_one; return real_main(); }
+int main(void) { io_debug_conn = debug_one; return real_main(); }

ccan/io/test/run-12-bidir-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-12-bidir.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-13-all-idle-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-13-all-idle.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-15-timeout-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-15-timeout.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-17-homemade-io-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-17-homemade-io.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }

ccan/io/test/run-17-homemade-io.c

@@ -81,7 +81,6 @@ static struct io_plan io_read_packet(struct packet *pkt,
 	plan.next_arg = arg;
 	plan.pollflag = POLLIN;
 
-	io_plan_debug(&plan);
 	return plan;
 }
 

ccan/io/test/run-18-errno-DEBUG.c

@@ -5,4 +5,4 @@ int real_main(void);
 #include "run-18-errno.c"
 #undef main
 static bool always_debug(struct io_conn *conn) { return true; }
-int main(void) { io_debug = always_debug; return real_main(); }
+int main(void) { io_debug_conn = always_debug; return real_main(); }