[vte] regex: Check whether PCRE2 was compiled with JIT support

[Christian Persch <chpe src gnome org>]

commit ad078eb4fec6ba5ec7c2c220fe987b45f87798eb
Author: Christian Persch <chpe src gnome org>
Date:   Fri Nov 2 20:27:20 2018 +0100

    regex: Check whether PCRE2 was compiled with JIT support
    
    ... and only warn once if it was not.

 src/vteregex.cc | 48 ++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 38 insertions(+), 10 deletions(-)
---
diff --git a/src/vteregex.cc b/src/vteregex.cc
index 7f6fb904..01ccfb99 100644
--- a/src/vteregex.cc
+++ b/src/vteregex.cc
@@ -152,6 +152,36 @@ vte_regex_unref(VteRegex *regex)
         return NULL;
 }
 
+static gboolean
+check_pcre_config_unicode(GError** error)
+{
+        /* Check library compatibility */
+        guint32 v;
+        int r = pcre2_config_8(PCRE2_CONFIG_UNICODE, &v);
+        if (r != 0 || v != 1) {
+                g_set_error(error, VTE_REGEX_ERROR, VTE_REGEX_ERROR_INCOMPATIBLE,
+                            "PCRE2 library was built without unicode support");
+                return FALSE;
+        }
+
+        return TRUE;
+}
+
+static gboolean
+check_pcre_config_jit(void)
+{
+        static gboolean warned = FALSE;
+
+        char s[256];
+        int r = pcre2_config_8(PCRE2_CONFIG_JITTARGET, &s);
+        if (r == PCRE2_ERROR_BADOPTION && !warned) {
+                g_printerr("PCRE2 library was built without JIT support\n");
+                warned = TRUE;
+        }
+
+        return r >= 1;
+}
+
 static VteRegex *
 vte_regex_new(VteRegexPurpose purpose,
               const char *pattern,
@@ -160,21 +190,15 @@ vte_regex_new(VteRegexPurpose purpose,
               GError    **error)
 {
         pcre2_code_8 *code;
-        int r, errcode;
-        guint32 v;
+        int errcode;
         PCRE2_SIZE erroffset;
 
         g_return_val_if_fail(pattern != NULL, NULL);
         g_return_val_if_fail(pattern_length >= -1, NULL);
         g_return_val_if_fail(error == NULL || *error == NULL, NULL);
 
-        /* Check library compatibility */
-        r = pcre2_config_8(PCRE2_CONFIG_UNICODE, &v);
-        if (r != 0 || v != 1) {
-                g_set_error(error, VTE_REGEX_ERROR, VTE_REGEX_ERROR_INCOMPATIBLE,
-                            "PCRE2 library was built without unicode support");
-                return NULL;
-        }
+        if (!check_pcre_config_unicode(error))
+                return FALSE;
 
         code = pcre2_compile_8((PCRE2_SPTR8)pattern,
                                pattern_length >= 0 ? pattern_length : PCRE2_ZERO_TERMINATED,
@@ -375,7 +399,8 @@ _vte_regex_get_pcre(VteRegex *regex)
  *
  * If the platform supports JITing, JIT compiles @regex.
  *
- * Returns: %TRUE if JITing succeeded, or %FALSE with @error filled in
+ * Returns: %TRUE if JITing succeeded (or PCRE2 was built without
+ *   JIT support), or %FALSE with @error filled in
  */
 gboolean
 vte_regex_jit(VteRegex *regex,
@@ -386,6 +411,9 @@ vte_regex_jit(VteRegex *regex,
 
         g_return_val_if_fail(regex != NULL, FALSE);
 
+        if (!check_pcre_config_jit())
+                return TRUE;
+
         r = pcre2_jit_compile_8(regex->code, flags);
         if (r < 0)
                 return set_gerror_from_pcre_error(r, error);