From 283c9d7ccffbcae0eee8fb3693597973b2fca55a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Helleu?= <flashcode@flashtux.org>
Date: Sun, 14 May 2023 14:09:49 +0200
Subject: [PATCH] irc: do not allow send of empty messages (single line or
 multiline)

---
 src/plugins/irc/irc-message.c               | 46 ++++++++++++++++++---
 src/plugins/irc/irc-message.h               |  1 +
 tests/unit/plugins/irc/test-irc-message.cpp | 24 +++++++++++
 3 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/src/plugins/irc/irc-message.c b/src/plugins/irc/irc-message.c
index 0be7cb1d6..c6fdae08b 100644
--- a/src/plugins/irc/irc-message.c
+++ b/src/plugins/irc/irc-message.c
@@ -637,6 +637,34 @@ irc_message_parse_cap_multiline_value (struct t_irc_server *server,
     weechat_hashtable_free (values);
 }
 
+/*
+ * Checks if a message is empty: either empty string or contains only newlines.
+ *
+ * Returns:
+ *   1: message is empty
+ *   0: message is NOT empty
+ */
+
+int
+irc_message_is_empty (const char *message)
+{
+    const char *ptr_msg;
+
+    if (!message || !message[0])
+        return 1;
+
+    ptr_msg = message;
+    while (ptr_msg && ptr_msg[0])
+    {
+        if (ptr_msg[0] != '\n')
+            return 0;
+        ptr_msg = weechat_utf8_next_char (ptr_msg);
+    }
+
+    /* only newlines => consider message is empty */
+    return 1;
+}
+
 /*
  * Encodes/decodes an IRC message using a charset.
  *
@@ -1309,6 +1337,10 @@ irc_message_split_privmsg_notice (struct t_irc_message_split_context *context,
 
     rc = 1;
 
+    /* privmsg/notice with empty message: not allowed */
+    if (irc_message_is_empty (arguments))
+        return 1;
+
     if (multiline)
     {
         index_multiline_args = 1;
@@ -1499,15 +1531,17 @@ irc_message_split (struct t_irc_server *server, const char *message)
     struct t_irc_message_split_context split_context;
     char **argv, **argv_eol, *tags, *host, *command, *arguments, target[4096];
     char *pos, monitor_action[3];
-    int split_ok, argc, index_args, max_length_nick, max_length_user;
-    int max_length_host, max_length_nick_user_host, split_msg_max_length;
-    int multiline, multiline_max_bytes, multiline_max_lines;
+    int split_ok, split_privmsg, argc, index_args, max_length_nick;
+    int max_length_user, max_length_host, max_length_nick_user_host;
+    int split_msg_max_length, multiline, multiline_max_bytes;
+    int multiline_max_lines;
 
     split_context.hashtable = NULL;
     split_context.number = 1;
     split_context.total_bytes = 0;
 
     split_ok = 0;
+    split_privmsg = 0;
     tags = NULL;
     host = NULL;
     command = NULL;
@@ -1679,6 +1713,7 @@ irc_message_split (struct t_irc_server *server, const char *message)
          * PRIVMSG target :some text here
          * NOTICE target :some text here
          */
+        split_privmsg = 1;
         if (index_args + 1 <= argc - 1)
         {
             split_ok = irc_message_split_privmsg_notice (
@@ -1738,8 +1773,9 @@ irc_message_split (struct t_irc_server *server, const char *message)
 
 end:
     if (!split_ok
-        || (weechat_hashtable_get_integer (split_context.hashtable,
-                                           "items_count") == 0))
+        || (!split_privmsg
+            && (weechat_hashtable_get_integer (split_context.hashtable,
+                                               "items_count") == 0)))
     {
         split_context.number = (message) ? 1 : 0;
         irc_message_split_add (&split_context,
diff --git a/src/plugins/irc/irc-message.h b/src/plugins/irc/irc-message.h
index 6583ff44a..b0670fba5 100644
--- a/src/plugins/irc/irc-message.h
+++ b/src/plugins/irc/irc-message.h
@@ -46,6 +46,7 @@ extern struct t_hashtable *irc_message_parse_to_hashtable (struct t_irc_server *
 extern struct t_hashtable *irc_message_parse_cap_value (const char *value);
 extern void irc_message_parse_cap_multiline_value (struct t_irc_server *server,
                                                    const char *value);
+extern int irc_message_is_empty (const char *message);
 extern char *irc_message_convert_charset (const char *message,
                                           int pos_start,
                                           const char *modifier,
diff --git a/tests/unit/plugins/irc/test-irc-message.cpp b/tests/unit/plugins/irc/test-irc-message.cpp
index 39a232c5a..3939060e9 100644
--- a/tests/unit/plugins/irc/test-irc-message.cpp
+++ b/tests/unit/plugins/irc/test-irc-message.cpp
@@ -946,6 +946,24 @@ convert_irc_charset_cb (const void *pointer, void *data,
     return new_string;
 }
 
+/*
+ * Tests functions:
+ *   irc_message_is_empty
+ */
+
+TEST(IrcMessage, IsEmpty)
+{
+    LONGS_EQUAL(1, irc_message_is_empty (NULL));
+    LONGS_EQUAL(1, irc_message_is_empty (""));
+    LONGS_EQUAL(1, irc_message_is_empty ("\n"));
+    LONGS_EQUAL(1, irc_message_is_empty ("\n\n\n\n\n\n\n\n"));
+
+    LONGS_EQUAL(0, irc_message_is_empty (" "));
+    LONGS_EQUAL(0, irc_message_is_empty ("\n "));
+    LONGS_EQUAL(0, irc_message_is_empty ("\n \n"));
+    LONGS_EQUAL(0, irc_message_is_empty ("test"));
+}
+
 /*
  * Tests functions:
  *   irc_message_convert_charset
@@ -1516,6 +1534,12 @@ TEST(IrcMessage, Split)
                  (const char *)hashtable_get (hashtable, "msg1"));
     hashtable_free (hashtable);
 
+    /* PRIVMSG with no content: no split (not allowed) */
+    hashtable = irc_message_split (server, "PRIVMSG #channel :");
+    CHECK(hashtable);
+    LONGS_EQUAL(0, hashtable->items_count);
+    hashtable_free (hashtable);
+
     /* PRIVMSG with small content: no split */
     hashtable = irc_message_split (server, "PRIVMSG #channel :test");
     CHECK(hashtable);