(encode_coding_string): Always return a unibyte string.

If NOCOPY is nonzero and there's no need of encoding, make STR
unibyte directly.

1 files changed, 28 insertions, 15 deletions

diff --git a/src/coding.c b/src/coding.c
index 79e32fbed60..2ab4296381a 100644
--- a/src/coding.c
+++ b/src/coding.c
@@ -6361,7 +6361,12 @@ encode_coding_string (str, coding, nocopy)
 
   if (SYMBOLP (coding->pre_write_conversion)
       && !NILP (Ffboundp (coding->pre_write_conversion)))
-    str = run_pre_post_conversion_on_str (str, coding, 1);
+    {
+      str = run_pre_post_conversion_on_str (str, coding, 1);
+      /* As STR is just newly generated, we don't have to copy it
+         anymore.  */
+      nocopy = 1;
+    }
 
   from = 0;
   to = SCHARS (str);
@@ -6369,21 +6374,10 @@ encode_coding_string (str, coding, nocopy)
 
   /* Encoding routines determine the multibyteness of the source text
      by coding->src_multibyte.  */
-  coding->src_multibyte = STRING_MULTIBYTE (str);
+  coding->src_multibyte = SCHARS (str) < SBYTES (str);
   coding->dst_multibyte = 0;
   if (! CODING_REQUIRE_ENCODING (coding))
-    {
-      coding->consumed = SBYTES (str);
-      coding->consumed_char = SCHARS (str);
-      if (STRING_MULTIBYTE (str))
-        {
-          str = Fstring_as_unibyte (str);
-          nocopy = 1;
-        }
-      coding->produced = SBYTES (str);
-      coding->produced_char = SCHARS (str);
-      return (nocopy ? str : Fcopy_sequence (str));
-    }
+    goto no_need_of_encoding;
 
   if (coding->composing != COMPOSITION_DISABLED)
     coding_save_composition (coding, from, to, str);
@@ -6399,7 +6393,7 @@ encode_coding_string (str, coding, nocopy)
       if (from == to_byte)
         {
           coding_free_composition_data (coding);
-          return (nocopy ? str : Fcopy_sequence (str));
+          goto no_need_of_encoding;
         }
       shrinked_bytes = from + (SBYTES (str) - to_byte);
     }
@@ -6444,6 +6438,25 @@ encode_coding_string (str, coding, nocopy)
   coding_free_composition_data (coding);
 
   return newstr;
+
+ no_need_of_encoding:
+  coding->consumed = SBYTES (str);
+  coding->consumed_char = SCHARS (str);
+  if (STRING_MULTIBYTE (str))
+    {
+      if (nocopy)
+        /* We are sure that STR doesn't contain a multibyte
+           character.  */
+        STRING_SET_UNIBYTE (str);
+      else
+        {
+          str = Fstring_as_unibyte (str);
+          nocopy = 1;
+        }
+    }
+  coding->produced = SBYTES (str);
+  coding->produced_char = SCHARS (str);
+  return (nocopy ? str : Fcopy_sequence (str));
 }