Fixed threading issue in Onigura Regex library

src/openalpr/postprocess/regexrule.cpp

@@ -21,6 +21,8 @@
 
 using namespace std;
 
+tthread::mutex regexrule_mutex_m;
+
 namespace alpr
 {
    
@@ -28,6 +30,7 @@ namespace alpr
   {   
     this->original = pattern;
     this->region = region;
+    this->regex = "";
 
     this->valid = false;
     string::iterator end_it = utf8::find_invalid(pattern.begin(), pattern.end());
@@ -90,13 +93,17 @@ namespace alpr
       numchars++;
     }
 
+    // Onigurama is not thread safe when compiling regex.  Using a mutex to ensure that
+    // we don't crash
+    regexrule_mutex_m.lock();
     UChar* cstr_pattern = (UChar* )this->regex.c_str();
     OnigErrorInfo einfo;
 
-    //cout << "Pattern: " << cstr_pattern << endl;
     int r = onig_new(&onig_regex, cstr_pattern, cstr_pattern + strlen((char* )cstr_pattern),
       ONIG_OPTION_DEFAULT, ONIG_ENCODING_UTF8, ONIG_SYNTAX_DEFAULT, &einfo);
 
+    regexrule_mutex_m.unlock(); 
+    
     if (r != ONIG_NORMAL) {
       //char s[ONIG_MAX_ERROR_MESSAGE_LEN];
       //onig_error_code_to_str(s, r, &einfo);

src/openalpr/postprocess/regexrule.h

@@ -26,6 +26,7 @@
 #include <vector>
 #include "support/regex/oniguruma.h"
 #include "support/utf8.h"
+#include "support/tinythread.h"
 
 namespace alpr
 {