message: Revise maxlen argument in msg_puts_attr_len

`attr` argument is enough to forbid putting message in history. Also forbid 
strings with NUL before `len` just in case (it appears that this does not ever 
happen).

1 files changed, 14 insertions, 9 deletions

diff --git a/src/nvim/message.c b/src/nvim/message.c
index 423f5a27e7..1eab9a403b 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -1562,13 +1562,17 @@ void msg_puts_attr(const char *const s, const int attr)
   msg_puts_attr_len(s, -1, attr);
 }
 
-/// Like msg_puts_attr(), but with a maximum length "maxlen" (in bytes).
-/// When "maxlen" is -1 there is no maximum length.
-/// When "maxlen" is >= 0 the message is not put in the history.
-void msg_puts_attr_len(const char *str, const ptrdiff_t maxlen, int attr)
+/// Write a message with highlight attributes
+///
+/// @param[in]  str  NUL-terminated message string.
+/// @param[in]  len  Length of the string or -1.
+/// @param[in]  attr  Highlight attribute.
+void msg_puts_attr_len(const char *const str, const ptrdiff_t len, int attr)
+  FUNC_ATTR_NONNULL_ALL
 {
+  assert(len < 0 || memchr(str, 0, len) == NULL);
   // If redirection is on, also write to the redirection file.
-  redir_write(str, maxlen);
+  redir_write(str, len);
 
   // Don't print anything when using ":silent cmd".
   if (msg_silent != 0) {
@@ -1576,8 +1580,9 @@ void msg_puts_attr_len(const char *str, const ptrdiff_t maxlen, int attr)
   }
 
   // if MSG_HIST flag set, add message to history
-  if ((attr & MSG_HIST) && maxlen < 0) {
-    add_msg_hist(str, -1, attr);
+  if (attr & MSG_HIST) {
+    assert(len < 0);
+    add_msg_hist(str, (int)len, attr);
     attr &= ~MSG_HIST;
   }
 
@@ -1596,9 +1601,9 @@ void msg_puts_attr_len(const char *str, const ptrdiff_t maxlen, int attr)
   // different, e.g. for Win32 console) or we just don't know where the
   // cursor is.
   if (msg_use_printf()) {
-    msg_puts_printf(str, maxlen);
+    msg_puts_printf(str, len);
   } else {
-    msg_puts_display((const char_u *)str, maxlen, attr, false);
+    msg_puts_display((const char_u *)str, len, attr, false);
   }
 }