1 files changed, 36 insertions, 26 deletions

diff --git a/gdb/ui-style.c b/gdb/ui-style.c
index f0a8e81..c8f2e11 100644
--- a/gdb/ui-style.c
+++ b/gdb/ui-style.c
@@ -1,5 +1,5 @@
 /* Styling for ui_file
-   Copyright (C) 2018-2024 Free Software Foundation, Inc.
+   Copyright (C) 2018-2025 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -21,12 +21,14 @@
 #include "gdbsupport/gdb_regex.h"
 
 /* A regular expression that is used for matching ANSI terminal escape
-   sequences.  */
+   sequences.  Note that this will actually match any prefix of such a
+   sequence.  This property is used so that other code can buffer
+   incomplete sequences as needed.  */
 
 static const char ansi_regex_text[] =
-  /* Introduction.  */
-  "^\033\\["
-#define DATA_SUBEXP 1
+  /* Introduction.  Only the escape character is truly required.  */
+  "^\033(\\["
+#define DATA_SUBEXP 2
   /* Capture parameter and intermediate bytes.  */
   "("
   /* Parameter bytes.  */
@@ -36,16 +38,17 @@ static const char ansi_regex_text[] =
   /* End the first capture.  */
   ")"
   /* The final byte.  */
-#define FINAL_SUBEXP 2
-  "([\x40-\x7e])";
+#define FINAL_SUBEXP 3
+  "([\x40-\x7e]))?";
 
 /* The number of subexpressions to allocate space for, including the
    "0th" whole match subexpression.  */
-#define NUM_SUBEXPRESSIONS 3
+#define NUM_SUBEXPRESSIONS 4
 
 /* The compiled form of ansi_regex_text.  */
 
-static regex_t ansi_regex;
+static compiled_regex ansi_regex (ansi_regex_text, REG_EXTENDED,
+  _("Error in ANSI terminal escape sequences regex"));
 
 /* This maps 8-color palette to RGB triples.  The values come from
    plain linux terminal.  */
@@ -364,12 +367,21 @@ ui_file_style::parse (const char *buf, size_t *n_read)
 {
   regmatch_t subexps[NUM_SUBEXPRESSIONS];
 
-  int match = regexec (&ansi_regex, buf, ARRAY_SIZE (subexps), subexps, 0);
+  int match = ansi_regex.exec (buf, ARRAY_SIZE (subexps), subexps, 0);
   if (match == REG_NOMATCH)
     {
       *n_read = 0;
       return false;
     }
+
+  /* If the final subexpression did not match, then that means there
+     was an incomplete sequence.  These are ignored here.  */
+  if (subexps[FINAL_SUBEXP].rm_so == -1)
+    {
+      *n_read = 0;
+      return false;
+    }
+
   /* Other failures mean the regexp is broken.  */
   gdb_assert (match == 0);
   /* The regexp is anchored.  */
@@ -526,27 +538,25 @@ ui_file_style::parse (const char *buf, size_t *n_read)
 
 /* See ui-style.h.  */
 
-bool
-skip_ansi_escape (const char *buf, int *n_read)
+ansi_escape_result
+examine_ansi_escape (const char *buf, int *n_read)
 {
+  gdb_assert (*buf == '\033');
+
   regmatch_t subexps[NUM_SUBEXPRESSIONS];
 
-  int match = regexec (&ansi_regex, buf, ARRAY_SIZE (subexps), subexps, 0);
-  if (match == REG_NOMATCH || buf[subexps[FINAL_SUBEXP].rm_so] != 'm')
-    return false;
+  int match = ansi_regex.exec (buf, ARRAY_SIZE (subexps), subexps, 0);
+  if (match == REG_NOMATCH)
+    return ansi_escape_result::NO_MATCH;
 
-  *n_read = subexps[FINAL_SUBEXP].rm_eo;
-  return true;
-}
+  if (subexps[FINAL_SUBEXP].rm_so == -1)
+    return ansi_escape_result::INCOMPLETE;
 
-void _initialize_ui_style ();
-void
-_initialize_ui_style ()
-{
-  int code = regcomp (&ansi_regex, ansi_regex_text, REG_EXTENDED);
-  /* If the regular expression was incorrect, it was a programming
-     error.  */
-  gdb_assert (code == 0);
+  if (buf[subexps[FINAL_SUBEXP].rm_so] != 'm')
+    return ansi_escape_result::NO_MATCH;
+
+  *n_read = subexps[FINAL_SUBEXP].rm_eo;
+  return ansi_escape_result::MATCHED;
 }
 
 /* See ui-style.h.  */