From 45f3f141850a0ac07c31906748752571652683df Mon Sep 17 00:00:00 2001
From: Garrett D'Amore <garrett@damore.org>
Date: Mon, 16 Apr 2018 11:40:28 -0700
Subject: fixes #344 nn_poll() legacy API missing

This includes the test from legacy libnanomsg and a man page.

We have refactored the message queue notification system so
that it uses nni_pollable, leading we hope to a more consistent
system, and reducing the code size and complexity.

We also fixed the size of the NN_RCVFD and NN_SNDFD so that they
are a SOCKET on Windows systems, rather than an integer.  This
addresses 64-bit compilation problems.
---
 src/core/msgqueue.c | 111 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 66 insertions(+), 45 deletions(-)

(limited to 'src/core/msgqueue.c')

diff --git a/src/core/msgqueue.c b/src/core/msgqueue.c
index 529e7f4d..212b52c2 100644
--- a/src/core/msgqueue.c
+++ b/src/core/msgqueue.c
@@ -31,11 +31,9 @@ struct nni_msgq {
 	nni_list mq_aio_putq;
 	nni_list mq_aio_getq;
 
-	// Callback - this function is executed with the lock held, and
-	// provides information about the current queue state anytime
-	// a message enters or leaves the queue, or a waiter is blocked.
-	nni_msgq_cb mq_cb_fn;
-	void *      mq_cb_arg;
+	// Pollable status.
+	nni_pollable *mq_sendable;
+	nni_pollable *mq_recvable;
 
 	// Filters.
 	nni_msgq_filter mq_filter_fn;
@@ -62,20 +60,20 @@ nni_msgq_init(nni_msgq **mqp, unsigned cap)
 		NNI_FREE_STRUCT(mq);
 		return (NNG_ENOMEM);
 	}
-
 	nni_aio_list_init(&mq->mq_aio_putq);
 	nni_aio_list_init(&mq->mq_aio_getq);
 	nni_mtx_init(&mq->mq_lock);
-
-	mq->mq_cap    = cap;
-	mq->mq_alloc  = alloc;
-	mq->mq_len    = 0;
-	mq->mq_get    = 0;
-	mq->mq_put    = 0;
-	mq->mq_closed = 0;
-	mq->mq_puterr = 0;
-	mq->mq_geterr = 0;
-	*mqp          = mq;
+	mq->mq_cap      = cap;
+	mq->mq_alloc    = alloc;
+	mq->mq_recvable = NULL;
+	mq->mq_sendable = NULL;
+	mq->mq_len      = 0;
+	mq->mq_get      = 0;
+	mq->mq_put      = 0;
+	mq->mq_closed   = 0;
+	mq->mq_puterr   = 0;
+	mq->mq_geterr   = 0;
+	*mqp            = mq;
 
 	return (0);
 }
@@ -101,6 +99,13 @@ nni_msgq_fini(nni_msgq *mq)
 		nni_msg_free(msg);
 	}
 
+	if (mq->mq_sendable) {
+		nni_pollable_free(mq->mq_sendable);
+	}
+	if (mq->mq_recvable) {
+		nni_pollable_free(mq->mq_recvable);
+	}
+
 	nni_free(mq->mq_msgs, mq->mq_alloc * sizeof(nng_msg *));
 	NNI_FREE_STRUCT(mq);
 }
@@ -292,36 +297,16 @@ nni_msgq_run_getq(nni_msgq *mq)
 static void
 nni_msgq_run_notify(nni_msgq *mq)
 {
-	if (mq->mq_cb_fn != NULL) {
-		int flags = 0;
-
-		if (mq->mq_closed) {
-			flags |= nni_msgq_f_closed;
-		}
-		if (mq->mq_len == 0) {
-			flags |= nni_msgq_f_empty;
-		} else if (mq->mq_len == mq->mq_cap) {
-			flags |= nni_msgq_f_full;
-		}
-		if (mq->mq_len < mq->mq_cap ||
-		    !nni_list_empty(&mq->mq_aio_getq)) {
-			flags |= nni_msgq_f_can_put;
-		}
-		if ((mq->mq_len != 0) || !nni_list_empty(&mq->mq_aio_putq)) {
-			flags |= nni_msgq_f_can_get;
-		}
-		mq->mq_cb_fn(mq->mq_cb_arg, flags);
+	if (mq->mq_len < mq->mq_cap || !nni_list_empty(&mq->mq_aio_getq)) {
+		nni_pollable_raise(mq->mq_sendable);
+	} else {
+		nni_pollable_clear(mq->mq_sendable);
+	}
+	if ((mq->mq_len != 0) || !nni_list_empty(&mq->mq_aio_putq)) {
+		nni_pollable_raise(mq->mq_recvable);
+	} else {
+		nni_pollable_clear(mq->mq_recvable);
 	}
-}
-
-void
-nni_msgq_set_cb(nni_msgq *mq, nni_msgq_cb fn, void *arg)
-{
-	nni_mtx_lock(&mq->mq_lock);
-	mq->mq_cb_fn  = fn;
-	mq->mq_cb_arg = arg;
-	nni_msgq_run_notify(mq);
-	nni_mtx_unlock(&mq->mq_lock);
 }
 
 static void
@@ -543,3 +528,39 @@ out:
 	nni_mtx_unlock(&mq->mq_lock);
 	return (0);
 }
+
+int
+nni_msgq_get_recvable(nni_msgq *mq, nni_pollable **sp)
+{
+	nni_mtx_lock(&mq->mq_lock);
+	if (mq->mq_recvable == NULL) {
+		int rv;
+		if ((rv = nni_pollable_alloc(&mq->mq_recvable)) != 0) {
+			nni_mtx_unlock(&mq->mq_lock);
+			return (rv);
+		}
+		nni_msgq_run_notify(mq);
+	}
+	nni_mtx_unlock(&mq->mq_lock);
+
+	*sp = mq->mq_recvable;
+	return (0);
+}
+
+int
+nni_msgq_get_sendable(nni_msgq *mq, nni_pollable **sp)
+{
+	nni_mtx_lock(&mq->mq_lock);
+	if (mq->mq_sendable == NULL) {
+		int rv;
+		if ((rv = nni_pollable_alloc(&mq->mq_sendable)) != 0) {
+			nni_mtx_unlock(&mq->mq_lock);
+			return (rv);
+		}
+		nni_msgq_run_notify(mq);
+	}
+	nni_mtx_unlock(&mq->mq_lock);
+
+	*sp = mq->mq_sendable;
+	return (0);
+}
-- 
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