[gtksourceview] implregex: keep things working with highlighting

[Christian Hergert <chergert src gnome org>]

commit 9fec311bb6ab77c08cc8016a1e03d5e0b4fa7f7e
Author: Christian Hergert <chergert redhat com>
Date:   Fri Jul 2 15:06:00 2021 -0700

    implregex: keep things working with highlighting
    
    This needs further investigation, but this keeps the highlighting working
    so that we don't regress there.

 gtksourceview/implregex.c | 39 ++++++++++++++++++++++-----------------
 1 file changed, 22 insertions(+), 17 deletions(-)
---
diff --git a/gtksourceview/implregex.c b/gtksourceview/implregex.c
index 978b3f88..6918de76 100644
--- a/gtksourceview/implregex.c
+++ b/gtksourceview/implregex.c
@@ -1025,6 +1025,7 @@ impl_match_info_next (ImplMatchInfo  *match_info,
 {
        gssize prev_end;
        gssize prev_begin;
+       int rc;
 
        GTK_SOURCE_PROFILER_BEGIN_MARK;
 
@@ -1047,13 +1048,13 @@ impl_match_info_next (ImplMatchInfo  *match_info,
 
        if (match_info->regex->has_jit)
        {
-               match_info->matches = pcre2_jit_match (match_info->regex->code,
-                                                      (PCRE2_SPTR)match_info->string,
-                                                      match_info->string_len,
-                                                      match_info->start_pos,
-                                                      match_info->match_flags,
-                                                      match_info->match_data,
-                                                      NULL);
+               rc = pcre2_jit_match (match_info->regex->code,
+                                     (PCRE2_SPTR)match_info->string,
+                                     match_info->string_len,
+                                     match_info->start_pos,
+                                     match_info->match_flags,
+                                     match_info->match_data,
+                                     NULL);
        }
        else
        {
@@ -1062,24 +1063,26 @@ impl_match_info_next (ImplMatchInfo  *match_info,
                if (match_info->regex->compile_flags & PCRE2_UTF)
                        match_flags |= PCRE2_NO_UTF_CHECK;
 
-               match_info->matches = pcre2_match (match_info->regex->code,
-                                                  (PCRE2_SPTR)match_info->string,
-                                                  match_info->string_len,
-                                                  match_info->start_pos,
-                                                  match_flags,
-                                                  match_info->match_data,
-                                                  NULL);
+               rc = pcre2_match (match_info->regex->code,
+                                 (PCRE2_SPTR)match_info->string,
+                                 match_info->string_len,
+                                 match_info->start_pos,
+                                 match_flags,
+                                 match_info->match_data,
+                                 NULL);
        }
 
-       if (set_regex_error (error, match_info->matches))
+       if (set_regex_error (error, rc))
        {
+               match_info->matches = rc;
+               match_info->start_pos = -1;
                return FALSE;
        }
 
        /* Avoid infinite loops if the pattern is an empty string or
         * something equivalent.
         */
-       if (match_info->start_pos == match_info->offsets[1])
+       if (prev_end == match_info->offsets[1])
        {
                if (match_info->start_pos > match_info->string_len)
                {
@@ -1115,6 +1118,8 @@ impl_match_info_next (ImplMatchInfo  *match_info,
                return impl_match_info_next (match_info, error);
        }
 
+       match_info->matches = rc;
+
        g_assert (match_info->offsets == pcre2_get_ovector_pointer (match_info->match_data));
 
        GTK_SOURCE_PROFILER_END_MARK (G_STRFUNC, NULL);
@@ -1148,5 +1153,5 @@ impl_match_info_get_match_count (const ImplMatchInfo *match_info)
 {
        g_return_val_if_fail (match_info != NULL, 0);
 
-       return match_info->matches;
+       return MAX (0, match_info->matches);
 }