MEDIUM: htx: Add a flag on a HTX message when no more data are expected

The HTX_FL_EOI flag must now be set on a HTX message when no more data are
expected. Most of time, it must be set before adding the EOM block. Thus, if
there is no space for the EOM, there is still an information to know all data
were received and pushed in the HTX message. There is only an exception for the
HTTP replies (deny, return...). For these messages, the flag is set after all
blocks are pushed in the message, including the EOM block, because, on error,
we remove all inserted data.
diff --git a/include/haproxy/htx-t.h b/include/haproxy/htx-t.h
index d9c08c8..d57404a 100644
--- a/include/haproxy/htx-t.h
+++ b/include/haproxy/htx-t.h
@@ -145,7 +145,9 @@
 #define HTX_FL_PROCESSING_ERROR  0x00000002 /* Set when a processing error occurred */
 #define HTX_FL_UPGRADE           0x00000004 /* Set when an upgrade is in progress */
 #define HTX_FL_PROXY_RESP        0x00000008 /* Set when the response was generated by HAProxy */
-
+#define HTX_FL_EOI               0x00000010 /* Set when end-of-input is reached from the HTX point of view
+					     * (at worst, on the EOM block is missing)
+					     */
 
 /* HTX block's type (max 15). */
 enum htx_blk_type {
diff --git a/include/haproxy/htx.h b/include/haproxy/htx.h
index a849f12..5ede1a3 100644
--- a/include/haproxy/htx.h
+++ b/include/haproxy/htx.h
@@ -585,6 +585,15 @@
 	return (htx->head != -1);
 }
 
+/* Returns 1 if no more data are expected for the message <htx>. Otherwise it
+ * returns 0. Note that it is illegal to call this with htx == NULL. Note also
+ * the EOM block may be missing.
+ */
+static inline int htx_expect_more(const struct htx *htx)
+{
+	return !(htx->flags & HTX_FL_EOI);
+}
+
 /* Copy an HTX message stored in the buffer <msg> to <htx>. We take care to
  * not overwrite existing data. All the message is copied or nothing. It returns
  * 1 on success and 0 on error.
diff --git a/src/cache.c b/src/cache.c
index 6fc1c14..533b902 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -926,6 +926,7 @@
 	}
 
 	if (appctx->st0 == HTX_CACHE_EOM) {
+		res_htx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
 		if (!htx_add_endof(res_htx, HTX_BLK_EOM)) {
 			si_rx_room_blk(si);
 			goto out;
diff --git a/src/h1_htx.c b/src/h1_htx.c
index 351980b..a2ee510 100644
--- a/src/h1_htx.c
+++ b/src/h1_htx.c
@@ -616,6 +616,8 @@
 		dsthtx->flags |= HTX_FL_PARSING_ERROR;
 		return 0;
 	}
+
+	dsthtx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
 	if (max < sizeof(struct htx_blk) + 1 || !htx_add_endof(dsthtx, HTX_BLK_EOM))
 		return 0;
 
diff --git a/src/hlua.c b/src/hlua.c
index 254c2a3..556de42 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -4582,6 +4582,7 @@
 	}
 
 	/* Finalize headers. */
+	htx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
 	if (!htx_add_endof(htx, HTX_BLK_EOH)) {
 		hlua_pusherror(L, "Lua applet http '%s': Failed create the response.\n",
 			       appctx->appctx->rule->arg.hlua_rule->fcn.name);
diff --git a/src/http_ana.c b/src/http_ana.c
index b77bf2a..7c1a1a1 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -4577,6 +4577,7 @@
 		channel_auto_close(res);
 		channel_shutr_now(res);
 		res->flags |= CF_EOI; /* The response is terminated, add EOI */
+		htxbuf(&res->buf)->flags |= HTX_FL_EOI; /* no more data are expected */
 	}
 	else {
 		/* Send ASAP informational messages. Rely on CF_EOI for final
diff --git a/src/mux_h2.c b/src/mux_h2.c
index 4b790e6..44955ba 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -4452,6 +4452,7 @@
 
 	if ((h2c->dff & H2_F_HEADERS_END_STREAM)) {
 		/* Mark the end of message using EOM */
+		htx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
 		if (!htx_add_endof(htx, HTX_BLK_EOM)) {
 			TRACE_STATE("failed to append HTX EOM block into rxbuf", H2_EV_RX_FRAME|H2_EV_RX_HDR|H2_EV_H2S_ERR, h2c->conn);
 			goto fail;
@@ -4587,6 +4588,7 @@
 	 */
 
 	if (h2c->dff & H2_F_DATA_END_STREAM) {
+		htx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
 		if (!htx_add_endof(htx, HTX_BLK_EOM)) {
 			TRACE_STATE("h2s rxbuf is full, failed to add EOM", H2_EV_RX_FRAME|H2_EV_RX_DATA|H2_EV_H2S_BLK, h2c->conn, h2s);
 			h2c->flags |= H2_CF_DEM_SFULL;
@@ -5778,6 +5780,8 @@
 		if (htx_is_empty(buf_htx))
 			cs->flags |= CS_FL_EOI;
 	}
+	else if (htx_is_empty(h2s_htx))
+		buf_htx->flags |= (h2s_htx->flags & HTX_FL_EOI);
 
 	buf_htx->extra = (h2s_htx->extra ? (h2s_htx->data + h2s_htx->extra) : 0);
 	htx_to_buf(buf_htx, buf);
diff --git a/src/stats.c b/src/stats.c
index d69c764..562cd82 100644
--- a/src/stats.c
+++ b/src/stats.c
@@ -3339,6 +3339,7 @@
 
 	if (appctx->st0 == STAT_HTTP_DONE) {
 		/* Don't add TLR because mux-h1 will take care of it */
+		res_htx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
 		if (!htx_add_endof(res_htx, HTX_BLK_EOM)) {
 			si_rx_room_blk(si);
 			goto out;
diff --git a/src/tcpcheck.c b/src/tcpcheck.c
index e83b915..fc64a10 100644
--- a/src/tcpcheck.c
+++ b/src/tcpcheck.c
@@ -1335,8 +1335,11 @@
 
 
 		if (!htx_add_endof(htx, HTX_BLK_EOH) ||
-		    (istlen(body) && !htx_add_data_atonce(htx, body)) ||
-		    !htx_add_endof(htx, HTX_BLK_EOM))
+		    (istlen(body) && !htx_add_data_atonce(htx, body)))
+			goto error_htx;
+
+		htx->flags |= HTX_FL_EOI; /* no more data are expected. Only EOM remains to add now */
+		if (!htx_add_endof(htx, HTX_BLK_EOM))
 			goto error_htx;
 
 		htx_to_buf(htx, &check->bo);