+/*---------- assigning articles to conns, and transmitting ----------*/
+
+static Article *dequeue_from(int peek, InputFile *ipf) {
+ if (!ipf) return 0;
+ if (peek) return LIST_HEAD(ipf->queue);
+
+ Article *art= LIST_REMHEAD(ipf->queue);
+ if (!art) return 0;
+ check_reading_pause_resume(ipf);
+ return art;
+}
+
+static Article *dequeue(int peek) {
+ Article *art;
+ art= dequeue_from(peek, flushing_input_file); if (art) return art;
+ art= dequeue_from(peek, backlog_input_file); if (art) return art;
+ art= dequeue_from(peek, main_input_file); if (art) return art;
+ return 0;
+}
+
+static void check_assign_articles(void) {
+ for (;;) {
+ if (!dequeue(1))
+ break;
+
+ Conn *walk, *use=0;
+ int spare=0, inqueue=0;
+
+ /* Find a connection to offer this article. We prefer a busy
+ * connection to an idle one, provided it's not full. We take the
+ * first (oldest) and since that's stable, it will mean we fill up
+ * connections in order. That way if we have too many
+ * connections, the spare ones will go away eventually.
+ */
+ FOR_CONN(walk) {
+ if (walk->quitting) continue;
+ inqueue= walk->sent.count + walk->priority.count
+ + walk->waiting.count;
+ spare= walk->max_queue - inqueue;
+ assert(inqueue <= max_queue_per_conn);
+ assert(spare >= 0);
+ if (inqueue==0) /*idle*/ { if (!use) use= walk; }
+ else if (spare>0) /*working*/ { use= walk; break; }
+ }
+ if (use) {
+ if (!inqueue) use->since_activity= 0; /* reset idle counter */
+ while (spare>0) {
+ Article *art= dequeue(0);
+ if (!art) break;
+ LIST_ADDTAIL(use->waiting, art);
+ lowvol_perperiod[lowvol_circptr]++;
+ spare--;
+ }
+ conn_maybe_write(use);
+ } else if (allow_connect_start()) {
+ connect_start();
+ break;
+ } else {
+ break;
+ }
+ }
+}
+
+static void *conn_writeable(oop_source *l, int fd, oop_event ev, void *u) {
+ conn_maybe_write(u);
+ return OOP_CONTINUE;
+}
+
+static void conn_maybe_write(Conn *conn) {
+ for (;;) {
+ conn_make_some_xmits(conn);
+ if (!conn->xmitu) {
+ loop->cancel_fd(loop, conn->fd, OOP_WRITE);
+ conn->oopwriting= 0;
+ return;
+ }
+
+ void *rp= conn_write_some_xmits(conn);
+ if (rp==OOP_CONTINUE) {
+ if (!conn->oopwriting) {
+ loop->on_fd(loop, conn->fd, OOP_WRITE, conn_writeable, conn);
+ conn->oopwriting= 1;
+ }
+ return;
+ } else if (rp==OOP_HALT) {
+ return;
+ } else if (!rp) {
+ /* transmitted everything */
+ } else {
+ abort();
+ }
+ }
+}
+
+/*---------- expiry, flow control and deferral ----------*/
+
+/*
+ * flow control notes
+ * to ensure articles go away eventually
+ * separate queue for each input file
+ * queue expiry
+ * every period, check head of backlog queue for expiry with SMretrieve
+ * if too old: discard, and check next article
+ * also check every backlog article as we read it
+ * flush expiry
+ * after too long in SEPARATED/DROPPING ie Separated/Finishing/Dropping
+ * one-off: eat queued articles from flushing and write them to defer
+ * one-off: connfail all connections which have any articles from flushing
+ * newly read articles from flushing go straight to defer
+ * this should take care of it and get us out of this state
+ * to avoid filling up ram needlessly
+ * input control
+ * limit number of queued articles for each ipf
+ * pause/resume inputfile tailing
+ */
+
+static void check_reading_pause_resume(InputFile *ipf) {
+ if (ipf->queue.count >= max_queue_per_ipf)
+ inputfile_reading_pause(ipf);
+ else
+ inputfile_reading_resume(ipf);
+}
+
+static void article_defer(Article *art /* not on a queue */, int whichcount) {
+ open_defer();
+ if (fprintf(defer, "%s %s\n", TokenToText(art->token), art->messageid) <0
+ || fflush(defer))
+ sysdie("write to defer file %s",path_defer);
+ article_done(art, whichcount);
+}
+
+static int article_check_expired(Article *art /* must be queued, not conn */) {
+ ARTHANDLE *artdata= SMretrieve(art->token, RETR_STAT);
+ if (artdata) { SMfreearticle(artdata); return 0; }
+
+ LIST_REMOVE(art->ipf->queue, art);
+ art->missing= 1;
+ art->ipf->count_nooffer_missing++;
+ article_done(art,-1);
+ return 1;
+}
+
+void inputfile_queue_check_expired(InputFile *ipf) {
+ if (!ipf) return;
+
+ for (;;) {
+ Article *art= LIST_HEAD(ipf->queue);
+ int expd= article_check_expired(art);
+ if (!expd) break;
+ }
+ check_reading_pause_resume(ipf);
+}
+
+static void article_autodefer(InputFile *ipf, Article *art) {
+ ipf->autodefer++;
+ article_defer(art,-1);
+}
+
+static int has_article_in(const ArticleList *al, InputFile *ipf) {
+ Article *art;
+ for (art=LIST_HEAD(*al); art; art=LIST_NEXT(art))
+ if (art->ipf == ipf) return 1;
+ return 0;
+}
+
+static void autodefer_input_file_articles(InputFile *ipf) {
+ Article *art;
+ while ((art= LIST_REMHEAD(ipf->queue)))
+ article_autodefer(ipf, art);
+}
+
+static void autodefer_input_file(InputFile *ipf) {
+ static const char *const abandon= "stuck";
+ ipf->autodefer= 0;
+
+ autodefer_input_file_articles(ipf);
+
+ if (ipf->inprogress) {
+ Conn *walk;
+ FOR_CONN(walk) {
+ if (has_article_in(&walk->waiting, ipf) ||
+ has_article_in(&walk->priority, ipf) ||
+ has_article_in(&walk->sent, ipf))
+ walk->quitting= abandon;
+ }
+ while (ipf->inprogress) {
+ FOR_CONN(walk)
+ if (walk->quitting == abandon) goto found;
+ abort(); /* where are they ?? */
+
+ found:
+ connfail(walk, "connection is stuck or crawling,"
+ " and we need to finish flush");
+ autodefer_input_file_articles(ipf);
+ }
+ }
+
+ check_reading_pause_resume(ipf);
+}
+
+/*========== article transmission ==========*/
+
+static XmitDetails *xmit_core(Conn *conn, const char *data, int len,
+ XmitKind kind) { /* caller must then fill in details */
+ struct iovec *v= &conn->xmit[conn->xmitu];
+ XmitDetails *d= &conn->xmitd[conn->xmitu++];
+ v->iov_base= (char*)data;
+ v->iov_len= len;
+ d->kind= kind;
+ return d;
+}
+
+static void xmit_noalloc(Conn *conn, const char *data, int len) {
+ xmit_core(conn,data,len, xk_Const);
+}
+#define XMIT_LITERAL(lit) (xmit_noalloc(conn, (lit), sizeof(lit)-1))
+
+static void xmit_artbody(Conn *conn, ARTHANDLE *ah /* consumed */) {
+ XmitDetails *d= xmit_core(conn, ah->data, ah->len, xk_Artdata);
+ d->info.sm_art= ah;
+}
+
+static void xmit_free(XmitDetails *d) {
+ switch (d->kind) {
+ case xk_Artdata: SMfreearticle(d->info.sm_art); break;
+ case xk_Const: break;
+ default: abort();
+ }
+}
+
+static void *conn_write_some_xmits(Conn *conn) {
+ /* return values:
+ * 0: nothing more to write, no need to call us again
+ * OOP_CONTINUE: more to write but fd not writeable
+ * OOP_HALT: disaster, have destroyed conn
+ */
+ for (;;) {
+ int count= conn->xmitu;
+ if (!count) return 0;
+
+ if (count > IOV_MAX) count= IOV_MAX;
+ ssize_t rs= writev(conn->fd, conn->xmit, count);
+ if (rs < 0) {
+ if (isewouldblock(errno)) return OOP_CONTINUE;
+ connfail(conn, "write failed: %s", strerror(errno));
+ return OOP_HALT;
+ }
+ assert(rs > 0);
+
+ int done;
+ for (done=0; rs; ) {
+ assert(done<conn->xmitu);
+ struct iovec *vp= &conn->xmit[done];
+ XmitDetails *dp= &conn->xmitd[done];
+ assert(vp->iov_len <= SSIZE_MAX);
+ if ((size_t)rs >= vp->iov_len) {
+ rs -= vp->iov_len;
+ xmit_free(dp); /* vp->iov_len -= vp->iov_len, etc. */
+ done++;
+ } else {
+ vp->iov_base= (char*)vp->iov_base + rs;
+ vp->iov_len -= rs;
+ break; /* rs -= rs */
+ }
+ }
+ int newu= conn->xmitu - done;
+ memmove(conn->xmit, conn->xmit + done, newu * sizeof(*conn->xmit));
+ memmove(conn->xmitd, conn->xmitd + done, newu * sizeof(*conn->xmitd));
+ conn->xmitu= newu;
+ }
+}
+
+static void conn_make_some_xmits(Conn *conn) {
+ for (;;) {
+ if (conn->xmitu+5 > CONNIOVS)
+ break;
+
+ Article *art= LIST_REMHEAD(conn->priority);
+ if (!art) art= LIST_REMHEAD(conn->waiting);
+ if (!art) break;
+
+ if (art->state >= art_Wanted || (conn->stream && nocheck)) {
+ /* actually send it */
+
+ ARTHANDLE *artdata= SMretrieve(art->token, RETR_ALL);
+
+ art->state=
+ art->state == art_Unchecked ? art_Unsolicited :
+ art->state == art_Wanted ? art_Wanted :
+ (abort(),-1);
+
+ if (!artdata) art->missing= 1;
+ art->ipf->counts[art->state][ artdata ? RC_sent : RC_missing ]++;
+
+ if (conn->stream) {
+ if (artdata) {
+ XMIT_LITERAL("TAKETHIS ");
+ xmit_noalloc(conn, art->messageid, art->midlen);
+ XMIT_LITERAL("\r\n");
+ xmit_artbody(conn, artdata);
+ } else {
+ article_done(art, -1);
+ continue;
+ }
+ } else {
+ /* we got 235 from IHAVE */
+ if (artdata) {
+ xmit_artbody(conn, artdata);
+ } else {
+ XMIT_LITERAL(".\r\n");
+ }
+ }
+
+ LIST_ADDTAIL(conn->sent, art);
+
+ } else {
+ /* check it */
+
+ if (conn->stream)
+ XMIT_LITERAL("CHECK ");
+ else
+ XMIT_LITERAL("IHAVE ");
+ xmit_noalloc(conn, art->messageid, art->midlen);
+ XMIT_LITERAL("\r\n");
+
+ assert(art->state == art_Unchecked);
+ art->ipf->counts[art->state][RC_sent]++;
+ LIST_ADDTAIL(conn->sent, art);
+ }
+ }
+}
+