dccp_send.c: Implement chunk queuing for dccp.

As Gerrit mentioned, it might be a good idea to use chunk
queueing also for dccp. This patch uses the new cq_xxx()
abstractions in the same way as the http sender.

Not heavily tested yet.

diff --git a/dccp_send.c b/dccp_send.c
index bdc7681e1de02469daaa0bc10698514eac563583..2c8f800f995ef8fafc6e97b35d3f4420ccddb60e 100644 (file)
--- a/dccp_send.c
+++ b/dccp_send.c
@@ -21,6 +21,7 @@
 #include "string.h"
 #include "fd.h"
 #include "close_on_fork.h"
+#include "chunk_queue.h"
 #include "server.cmdline.h"
 
 /** the list of connected clients **/
@@ -28,6 +29,9 @@ static struct list_head clients;
 static int listen_fd = -1;
 static struct sender *self;
 
+/** Maximal number of bytes in a chunk queue. */
+#define DCCP_MAX_PENDING_BYTES 40000
+
 /** describes one connected client */
 struct dccp_client {
        /** the dccp socket */
@@ -38,6 +42,8 @@ struct dccp_client {
        struct list_head node;
        /** non-zero if audio file header has been sent */
        int header_sent;
+       /** The list of pending chunks for this client. */
+       struct chunk_queue *cq;
 };
 
 static void dccp_pre_select( int *max_fileno, fd_set *rfds,
@@ -67,6 +73,7 @@ static void dccp_post_select(fd_set *rfds, __a_unused fd_set *wfds)
        para_list_add(&dc->node, &clients);
        add_close_on_fork_list(dc->fd);
        mark_fd_nonblock(dc->fd);
+       dc->cq = cq_new(DCCP_MAX_PENDING_BYTES);
 }
 
 static int dccp_open(void)
@@ -90,8 +97,10 @@ static int dccp_open(void)
        if (ret < 0)
                return ret;
        ret = listen(listen_fd, 0);
-       if (ret < 0)
+       if (ret < 0) {
+               PARA_ERROR_LOG("%s\n", strerror(errno));
                return -E_DCCP_LISTEN;
+       }
        PARA_DEBUG_LOG("listening on fd %d\n", listen_fd);
        add_close_on_fork_list(listen_fd);
        mark_fd_nonblock(listen_fd);
@@ -104,10 +113,15 @@ static void dccp_shutdown_client(struct dccp_client *dc)
                dc->fd);
        close(dc->fd);
        del_close_on_fork_list(dc->fd);
+       cq_destroy(dc->cq);
        list_del(&dc->node);
        free(dc);
 }
 
+/*
+ * ret: Negative on errors, zero if nothing was written and write would block,
+ * number of bytes written else.
+ */
 static int dccp_write(int fd, const char *buf, size_t len)
 {
        size_t written = 0;
@@ -119,17 +133,51 @@ static int dccp_write(int fd, const char *buf, size_t len)
                 * Error handling: CCID3 has a sending wait queue which fills up and is
                 * emptied asynchronously. The EAGAIN case means that there is currently
                 * no space in the wait queue, but this can change at any moment and is
-                * thus not an error condition. Keep polling until an entry becomes free.
+                * thus not an error condition.
                 */
                if (ret < 0 && errno == EAGAIN)
-                       continue;
-               if (ret < 0)
+                       return written;
+               if (ret < 0) {
+                       PARA_ERROR_LOG("%s\n", strerror(errno));
                        return -E_DCCP_WRITE;
+               }
                written += ret;
        }
        return written;
 }
 
+static int queue_chunk_or_shutdown(struct dccp_client *dc, long unsigned chunk_num,
+       size_t sent)
+{
+       int ret = cq_enqueue(dc->cq, chunk_num, sent);
+       if (ret < 0) {
+               PARA_NOTICE_LOG("enqueue error\n");
+               dccp_shutdown_client(dc);
+       }
+       return ret;
+}
+
+static int send_queued_chunks(struct dccp_client *dc)
+{
+       struct queued_chunk *qc;
+       while ((qc = cq_peek(dc->cq))) {
+               char *buf;
+               size_t len;
+               int ret = write_ok(dc->fd);
+               if (ret <= 0)
+                       return ret? -E_WRITE_OK : 0;
+               cq_get(qc, &buf, &len);
+               ret = dccp_write(dc->fd, buf, len);
+               if (ret < 0)
+                       return ret;
+               cq_update(dc->cq, ret);
+               if (ret != len)
+                       return 1;
+               cq_dequeue(dc->cq);
+       }
+       return 1;
+}
+
 static void dccp_send(long unsigned current_chunk,
                __a_unused long unsigned chunks_sent, const char *buf, size_t len)
 {
@@ -142,39 +190,28 @@ static void dccp_send(long unsigned current_chunk,
                return;
 
        list_for_each_entry_safe(dc, tmp, &clients, node) {
-               ret = write_ok(dc->fd);
-               if (ret < 0) {
-                       dccp_shutdown_client(dc);
-                       continue;
-               }
-               if (!ret)
-                       continue;
                if (!dc->header_sent && current_chunk) {
                        header_buf = vss_get_header(&header_len);
                        if (header_buf && header_len > 0) {
-                               ret = dccp_write(dc->fd, header_buf, header_len);
-                               if (ret != header_len) {
-                                       int err = errno;
-                                       PARA_ERROR_LOG("header write: %d/%u (%s)\n",
-                                               ret, header_len, ret < 0?
-                                               strerror(err) : "");
-                                       dccp_shutdown_client(dc);
-                                       continue;
-                               }
-                               dc->header_sent = 1;
-                               ret = write_ok(dc->fd);
-                               if (ret < 0) {
-                                       dccp_shutdown_client(dc);
-                                       continue;
-                               }
-                               if (!ret)
+                               if (queue_chunk_or_shutdown(dc, -1U, 0) < 0)
                                        continue;
                        }
+                       dc->header_sent = 1;
+               }
+               ret = send_queued_chunks(dc);
+               if (ret < 0) {
+                       dccp_shutdown_client(dc);
+                       continue;
                }
 //             PARA_DEBUG_LOG("writing %d bytes to fd %d\n", len, dc->fd);
                ret = dccp_write(dc->fd, buf, len);
-               if (ret != len)
+               if (ret < 0) {
+                       PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-ret));
                        dccp_shutdown_client(dc);
+                       continue;
+               }
+               if (ret != len)
+                       queue_chunk_or_shutdown(dc, current_chunk, ret);
        }
 }