MEDIUM: http-rules: Make early-hint custom actions

Now, the early-hint action uses its own dedicated action and is no longer
handled "in place" during the HTTP rules evaluation. Thus the action name
ACT_HTTP_EARLY_HINT is removed. In additionn, http_add_early_hint_header() and
http_reply_103_early_hints() are also removed. This part is now handled in the
new action_ptr callback function.
diff --git a/include/types/action.h b/include/types/action.h
index 6d77f9c..0016796 100644
--- a/include/types/action.h
+++ b/include/types/action.h
@@ -84,7 +84,6 @@
 	ACT_HTTP_SET_LOGL,
 	ACT_HTTP_SET_TOS,
 	ACT_HTTP_SET_MARK,
-	ACT_HTTP_EARLY_HINT,
 
 	/* http request actions. */
 	ACT_HTTP_REQ_TARPIT,
diff --git a/src/http_act.c b/src/http_act.c
index 537b1d0..60b65c4 100644
--- a/src/http_act.c
+++ b/src/http_act.c
@@ -944,6 +944,86 @@
 	return ACT_RET_PRS_OK;
 }
 
+/* This function executes a early-hint action. It adds an HTTP Early Hint HTTP
+ * 103 response header with <.arg.http.str> name and with a value built
+ * according to <.arg.http.fmt> log line format. If it is the first early-hint
+ * rule of a serie, the 103 response start-line is added first. At the end, if
+ * the next rule is not an early-hint rule or if it is the last rule, the EOH
+ * block is added to terminate the response. On success, it returns
+ * ACT_RET_CONT. If an error occurs while soft rewrites are enabled, the action
+ * is canceled, but the rule processing continue. Otherwsize ACT_RET_ERR is
+ * returned.
+ */
+static enum act_return http_action_early_hint(struct act_rule *rule, struct proxy *px,
+					      struct session *sess, struct stream *s, int flags)
+{
+	struct act_rule *prev_rule, *next_rule;
+	struct channel *res = &s->res;
+	struct htx *htx = htx_from_buf(&res->buf);
+	struct buffer *value = alloc_trash_chunk();
+	enum act_return ret = ACT_RET_CONT;
+
+	if (!(s->txn->req.flags & HTTP_MSGF_VER_11))
+		goto leave;
+
+	if (!value) {
+		if (!(s->flags & SF_ERR_MASK))
+			s->flags |= SF_ERR_RESOURCE;
+		goto error;
+	}
+
+	/* get previous and next rules */
+	prev_rule = LIST_PREV(&rule->list, typeof(rule), list);
+	next_rule = LIST_NEXT(&rule->list, typeof(rule), list);
+
+	/* if no previous rule or previous rule is not early-hint, start a new response. Otherwise,
+	 * continue to add link to a previously started response */
+	if (&prev_rule->list == s->current_rule_list || prev_rule->action_ptr != http_action_early_hint) {
+		struct htx_sl *sl;
+		unsigned int flags = (HTX_SL_F_IS_RESP|HTX_SL_F_VER_11|
+				      HTX_SL_F_XFER_LEN|HTX_SL_F_BODYLESS);
+
+		sl = htx_add_stline(htx, HTX_BLK_RES_SL, flags,
+				    ist("HTTP/1.1"), ist("103"), ist("Early Hints"));
+		if (!sl)
+			goto error;
+		sl->info.res.status = 103;
+	}
+
+	/* Add the HTTP Early Hint HTTP 103 response heade */
+	value->data = build_logline(s, b_tail(value), b_room(value), &rule->arg.http.fmt);
+	if (!htx_add_header(htx, rule->arg.http.str, ist2(b_head(value), b_data(value))))
+		goto error;
+
+	/* if it is the last rule or the next one is not an early-hint, terminate the current
+	 * response. */
+	if (&next_rule->list == s->current_rule_list || next_rule->action_ptr != http_action_early_hint) {
+		size_t data;
+
+		if (!htx_add_endof(htx, HTX_BLK_EOH)) {
+			/* If an error occurred during an Early-hint rule,
+			 * remove the incomplete HTTP 103 response from the
+			 * buffer */
+			goto error;
+		}
+
+		data = htx->data - co_data(res);
+		c_adv(res, data);
+		res->total += data;
+	}
+
+  leave:
+	free_trash_chunk(value);
+	return ret;
+
+  error:
+	/* If an error occurred during an Early-hint rule, remove the incomplete
+	 * HTTP 103 response from the buffer */
+	channel_htx_truncate(res, htx);
+	ret = ACT_RET_ERR;
+	goto leave;
+}
+
 /* This function executes a set-header or add-header actions. It builds a string
  * in the trash from the specified format string. It finds the action to be
  * performed in <.action>, previously filled by function parse_set_header(). The
@@ -1016,8 +1096,10 @@
 {
 	int cap, cur_arg;
 
-	if (args[*orig_arg-1][0] == 'e')
-		rule->action = ACT_HTTP_EARLY_HINT;
+	if (args[*orig_arg-1][0] == 'e') {
+		rule->action = ACT_CUSTOM;
+		rule->action_ptr = http_action_early_hint;
+	}
 	else {
 		if (args[*orig_arg-1][0] == 's')
 			rule->action = 0; // set-header
diff --git a/src/http_ana.c b/src/http_ana.c
index 9f6c90e..d21d19e 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -2728,75 +2728,6 @@
 	return 0;
 }
 
-/* Terminate a 103-Erly-hints response and send it to the client. It returns 0
- * on success and -1 on error. The response channel is updated accordingly.
- */
-static int http_reply_103_early_hints(struct channel *res)
-{
-	struct htx *htx = htx_from_buf(&res->buf);
-	size_t data;
-
-	if (!htx_add_endof(htx, HTX_BLK_EOH)) {
-		/* If an error occurred during an Early-hint rule,
-		 * remove the incomplete HTTP 103 response from the
-		 * buffer */
-		channel_htx_truncate(res, htx);
-		return -1;
-	}
-
-	data = htx->data - co_data(res);
-	c_adv(res, data);
-	res->total += data;
-	return 0;
-}
-
-/*
- * Build an HTTP Early Hint HTTP 103 response header with <name> as name and with a value
- * built according to <fmt> log line format.
- * If <early_hints> is 0, it is starts a new response by adding the start
- * line. If an error occurred -1 is returned. On success 0 is returned. The
- * channel is not updated here. It must be done calling the function
- * http_reply_103_early_hints().
- */
-static int http_add_early_hint_header(struct stream *s, int early_hints, const struct ist name, struct list *fmt)
-{
-	struct channel *res = &s->res;
-	struct htx *htx = htx_from_buf(&res->buf);
-	struct buffer *value = alloc_trash_chunk();
-
-	if (!value) {
-		if (!(s->flags & SF_ERR_MASK))
-			s->flags |= SF_ERR_RESOURCE;
-		goto fail;
-	}
-
-	if (!early_hints) {
-		struct htx_sl *sl;
-		unsigned int flags = (HTX_SL_F_IS_RESP|HTX_SL_F_VER_11|
-				      HTX_SL_F_XFER_LEN|HTX_SL_F_BODYLESS);
-
-		sl = htx_add_stline(htx, HTX_BLK_RES_SL, flags,
-				    ist("HTTP/1.1"), ist("103"), ist("Early Hints"));
-		if (!sl)
-			goto fail;
-		sl->info.res.status = 103;
-	}
-
-	value->data = build_logline(s, b_tail(value), b_room(value), fmt);
-	if (!htx_add_header(htx, name, ist2(b_head(value), b_data(value))))
-		goto fail;
-
-	free_trash_chunk(value);
-	return 0;
-
-  fail:
-	/* If an error occurred during an Early-hint rule, remove the incomplete
-	 * HTTP 103 response from the buffer */
-	channel_htx_truncate(res, htx);
-	free_trash_chunk(value);
-	return -1;
-}
-
 /* This function executes one of the set-{method,path,query,uri} actions. It
  * takes the string from the variable 'replace' with length 'len', then modifies
  * the relevant part of the request line accordingly. Then it updates various
@@ -3028,36 +2959,6 @@
 					http_remove_header(htx, &ctx);
 				break;
 
-			case ACT_HTTP_EARLY_HINT: {
-				struct act_rule *prev_rule, *next_rule;
-				int early_hints;
-
-				if (!(txn->req.flags & HTTP_MSGF_VER_11))
-					break;
-
-				/* get previous and next rules */
-				prev_rule = LIST_PREV(&rule->list, typeof(rule), list);
-				next_rule = LIST_NEXT(&rule->list, typeof(rule), list);
-
-				/* if no previous rule or previous rule is not early-hint, start a new response. Otherwise,
-				 * continue to add link to a previously started response */
-				early_hints = (&prev_rule->list != rules && prev_rule->action == ACT_HTTP_EARLY_HINT);
-
-				if (http_add_early_hint_header(s, early_hints, rule->arg.http.str, &rule->arg.http.fmt) == -1) {
-					rule_ret = HTTP_RULE_RES_ERROR;
-					goto end;
-				}
-				/* if it is the last rule or the next one is not an early-hint, terminate the current
-				 * response. */
-				if (&next_rule->list == rules || next_rule->action != ACT_HTTP_EARLY_HINT) {
-					if (http_reply_103_early_hints(&s->res) == -1) {
-						rule_ret = HTTP_RULE_RES_ERROR;
-						goto end;
-					}
-				}
-				break;
-			}
-
 			case ACT_ACTION_TRK_SC0 ... ACT_ACTION_TRK_SCMAX:
 				/* Note: only the first valid tracking parameter of each
 				 * applies.