Handle whitespace in TrxBoundaryParser

TheBoundaryMatcher is not updated as it is likely it will be removed
altogether. A regex that accepts comments in all relevant places becomes
so hairy it is unmaintainable. It seems that the only working solution
would be to first remove all comments and then perform the regex.

server/core/maxscale/trxboundaryparser.hh

@@ -97,8 +97,10 @@ public:
     {
         uint32_t type_mask = 0;
 
-        if (modutil_extract_SQL(pBuf, &m_pSql, &m_len))
+        char* pSql;
+        if (modutil_extract_SQL(pBuf, &pSql, &m_len))
         {
+            m_pSql = pSql;
             m_pI = m_pSql;
             m_pEnd = m_pI + m_len;
 
@@ -123,7 +125,7 @@ private:
 
     void log_exhausted()
     {
-#ifndef NDEBUG
+#ifdef SS_DEBUG
         MXS_WARNING("More tokens expected in statement '%.*s'.", (int)m_len, m_pSql);
 #endif
     }
@@ -490,14 +492,115 @@ private:
         return token;
     }
 
+    void bypass_whitespace()
+    {
+        while (m_pI != m_pEnd)
+        {
+            if (isspace(*m_pI))
+            {
+                ++m_pI;
+            }
+            else if (*m_pI == '/') // Might be a comment
+            {
+                if ((m_pI + 1 != m_pEnd) && (*(m_pI + 1) == '*')) // Indeed it was
+                {
+                    m_pI += 2;
+
+                    while (m_pI != m_pEnd)
+                    {
+                        if (*m_pI == '*') // Might be the end of the comment
+                        {
+                            ++m_pI;
+
+                            if (m_pI != m_pEnd)
+                            {
+                                if (*m_pI == '/') // Indeed it was
+                                {
+                                    ++m_pI;
+                                    break; // Out of this inner while.
+                                }
+                            }
+                        }
+                        else
+                        {
+                            // It was not the end of the comment.
+                            ++m_pI;
+                        }
+                    }
+                }
+                else
+                {
+                    // Was not a comment, so we'll bail out.
+                    break;
+                }
+            }
+            else if (*m_pI == '-') // Might be the start of a comment to the end of line
+            {
+                bool is_comment = false;
+
+                if (m_pI + 1 != m_pEnd)
+                {
+                    if (*(m_pI + 1) == '-') // Might be, yes.
+                    {
+                        if (m_pI + 2 != m_pEnd)
+                        {
+                            if (isspace(*(m_pI + 2))) // Yes, it is.
+                            {
+                                is_comment = true;
+
+                                m_pI += 3;
+
+                                while ((m_pI != m_pEnd) && (*m_pI != '\n'))
+                                {
+                                    ++m_pI;
+                                }
+
+                                if (m_pI != m_pEnd)
+                                {
+                                    ss_dassert(*m_pI == '\n');
+                                    ++m_pI;
+                                }
+                            }
+                        }
+                    }
+                }
+
+                if (!is_comment)
+                {
+                    break;
+                }
+            }
+            else if (*m_pI == '#')
+            {
+                ++m_pI;
+
+                while ((m_pI != m_pEnd) && (*m_pI != '\n'))
+                {
+                    ++m_pI;
+                }
+
+                if (m_pI != m_pEnd)
+                {
+                    ss_dassert(*m_pI == '\n');
+                    ++m_pI;
+                }
+
+                m_pI = m_pEnd;
+                break;
+            }
+            else
+            {
+                // Neither whitespace not start of a comment, so we bail out.
+                break;
+            }
+        }
+    }
+
     token_t next_token(token_required_t required = TOKEN_NOT_REQUIRED)
     {
         token_t token = PARSER_UNKNOWN_TOKEN;
 
-        while ((m_pI != m_pEnd) && isblank(*m_pI))
-        {
-            ++m_pI;
-        }
+        bypass_whitespace();
 
         if (m_pI == m_pEnd)
         {
@@ -507,7 +610,7 @@ private:
         {
             ++m_pI;
 
-            while ((m_pI != m_pEnd) && isblank(*m_pI))
+            while ((m_pI != m_pEnd) && isspace(*m_pI))
             {
                 ++m_pI;
             }
@@ -668,7 +771,7 @@ private:
     TrxBoundaryParser& operator = (const TrxBoundaryParser&);
 
 private:
-    char*       m_pSql;
+    const char* m_pSql;
     int         m_len;
     const char* m_pI;
     const char* m_pEnd;