Implement write queue for iomux

src/wqueue.c

@@ -0,0 +1,112 @@
+#include <assert.h>
+#include <string.h>
+#include "ucore/wqueue.h"
+#include "ucore/iomux.h"
+
+static int uc_wqueue_handle_write(struct UCWQueue *wqueue)
+{
+    int rc;
+    struct IOMuxFD *fd = &wqueue->fd;
+    struct IOMux *mux  = wqueue->mux;
+
+    while (!uc_tailq_empty(&wqueue->queue)) {
+        struct TailQ *q;
+        struct MBuf *mbuf;
+        q = UC_TAILQ_FIRST(&wqueue->queue);
+
+        mbuf = UC_TAILQ_CONTAINER(q, struct MBuf, entry);
+        rc = wqueue->write_cb(mux, fd, mbuf);
+        if (rc <= 0) {
+            //NOTE for rc < 0, nothing can touch the wqueue or fd
+            //any more, as it might been free'd
+            break;
+        }
+
+        mbuf = uc_mbuf_dequeue(&wqueue->queue);
+        assert(mbuf != NULL);
+        uc_mbuf_free(mbuf);
+        wqueue->queue_len--;
+    }
+
+    if (rc >= 0 && uc_tailq_empty(&wqueue->queue)
+        && (wqueue->fd.what & MUX_EV_WRITE) != 0) {
+
+        int urc;
+
+        urc = iomux_update_events(mux, 
+                                  fd, 
+                                  wqueue->fd.what & ~MUX_EV_WRITE);
+        assert(urc == 0);
+
+    }
+
+    return rc;
+}
+
+static void uc_wqueue_cb(struct IOMux *mux, struct IOMuxFD *fd, unsigned int what)
+{
+    int rc = 0;
+    struct UCWQueue *wqueue = UC_CONTAINER_OF(fd, struct UCWQueue, fd);
+
+    if (what & MUX_EV_WRITE) {
+        rc = uc_wqueue_handle_write(wqueue);
+        //NOTE - can't touch the wqueue or fd if rc < 0
+        //as it might been free'd
+    }
+
+
+    if (rc >= 0 && what & MUX_EV_READ) {
+        rc = wqueue->read_cb(mux, fd);
+        //NOTE - can't touch the wqueue or fd after this point,
+        //as it might been free'd
+    }
+}
+
+void uc_wqueue_init(struct UCWQueue *wqueue, struct IOMux *mux)
+{
+    assert(mux != NULL);
+
+    memset(wqueue, 0, sizeof *wqueue);
+    wqueue->mux = mux;
+    wqueue->fd.callback = uc_wqueue_cb;
+    
+    uc_tailq_init(&wqueue->queue);
+}
+
+int uc_wqueue_clear(struct UCWQueue *wqueue)
+{
+    struct MBuf *buf;
+    int rc;
+
+    while ((buf = uc_mbuf_dequeue(&wqueue->queue)) != NULL) {
+        uc_mbuf_free(buf);
+        wqueue->queue_len--;
+    }
+
+    if ((wqueue->fd.what & MUX_EV_WRITE) != 0) {
+        rc = iomux_update_events(wqueue->mux, 
+                                &wqueue->fd, 
+                                wqueue->fd.what & ~MUX_EV_WRITE);
+    }
+
+    assert(rc == 0);
+
+    return rc;
+}
+
+int uc_wqueue_enqueue(struct UCWQueue *wqueue, struct MBuf *mbuf)
+{
+    int rc = 0;
+
+    uc_mbuf_enqueue(mbuf, &wqueue->queue);
+    wqueue->queue_len++;
+
+    if ((wqueue->fd.what & MUX_EV_WRITE) == 0) {
+        rc = iomux_update_events(wqueue->mux, 
+                                &wqueue->fd, 
+                                wqueue->fd.what | MUX_EV_WRITE);
+        assert(rc == 0);
+    }
+
+    return 0;
+}