MXS-2302: Remove templates from parsing code

The templates were only used to make testing easier and upon review the
gain in testing convenience wasn't large enough to warrant its use.

server/modules/filter/hintfilter/hintparser.cc

@@ -24,6 +24,8 @@
  * Code for parsing SQL comments and processing them into MaxScale hints
  */
 
+using InputIter = mxs::Buffer::iterator;
+
 /* Parser tokens for the hint parser */
 typedef enum
 {
@@ -52,7 +54,6 @@ typedef enum
  *
  * @return The iterator pointing at the first occurrence of the character or `end` if one was not found
  */
-template<class InputIter>
 InputIter skip_until(InputIter it, InputIter end, char c)
 {
     while (it != end)
@@ -84,7 +85,6 @@ InputIter skip_until(InputIter it, InputIter end, char c)
  * @return A pair of iterators pointing to the range the comment spans. The comment tags themselves are not
  *         included in this range. If no comment is found, a pair of `end` iterators is returned.
  */
-template<class InputIter>
 std::pair<InputIter, InputIter> get_comment(InputIter it, InputIter end)
 {
     while (it != end)
@@ -158,7 +158,6 @@ std::pair<InputIter, InputIter> get_comment(InputIter it, InputIter end)
  *
  * @return A list of iterator pairs pointing to all comments in the query
  */
-template<class InputIter>
 std::vector<std::pair<InputIter, InputIter>> get_all_comments(InputIter start, InputIter end)
 {
     std::vector<std::pair<InputIter, InputIter>> rval;
@@ -180,7 +179,6 @@ std::vector<std::pair<InputIter, InputIter>> get_all_comments(InputIter start, I
 }
 
 // Simple container for two iterators and a token type
-template<class InputIter>
 struct Token
 {
     InputIter   begin;
@@ -212,8 +210,7 @@ static const std::unordered_map<std::string, TOKEN_VALUE> tokens
  *
  * @return The next token
  */
-template<class InputIter>
+Token next_token(InputIter* iter, InputIter end)
-Token<InputIter> next_token(InputIter* iter, InputIter end)
 {
     InputIter& it = *iter;
 
@@ -265,7 +262,6 @@ Token<InputIter> next_token(InputIter* iter, InputIter end)
  *
  * @return The processed hint or NULL on invalid input
  */
-template<class InputIter>
 HINT* process_definition(InputIter it, InputIter end)
 {
     HINT* rval = nullptr;
@@ -324,7 +320,6 @@ HINT* process_definition(InputIter it, InputIter end)
     return rval;
 }
 
-template<class InputIter>
 HINT* HINT_SESSION::process_comment(InputIter it, InputIter end)
 {
     HINT* rval = nullptr;

server/modules/filter/hintfilter/mysqlhint.hh

@@ -39,7 +39,7 @@ private:
     std::vector<HINT*>                     stack;
     std::unordered_map<std::string, HINT*> named_hints;
 
-    template<class InputIter>
+    using InputIter = mxs::Buffer::iterator;
     HINT* process_comment(InputIter it, InputIter end);
     void  process_hints(GWBUF* buffer);
 

server/modules/filter/hintfilter/test/test_hintparser.cc

@@ -27,8 +27,9 @@ void test(const std::string& input, std::initializer_list<std::string> expected)
 {
     bool rval = true;
     auto it = expected.begin();
+    mxs::Buffer buffer(input.c_str(), input.size());
 
-    for (auto output : get_all_comments(input.begin(), input.end()))
+    for (auto output : get_all_comments(buffer.begin(), buffer.end()))
     {
         if (it == expected.end())
         {
@@ -76,7 +77,9 @@ static HINT_SESSION session(nullptr);
 
 void test_parse(const std::string& input, int expected_type)
 {
-    for (auto comment : get_all_comments(input.begin(), input.end()))
+    mxs::Buffer buffer(input.c_str(), input.size());
+
+    for (auto comment : get_all_comments(buffer.begin(), buffer.end()))
     {
         std::string comment_str(comment.first, comment.second);
         HINT* hint = session.process_comment(comment.first, comment.second);
@@ -100,8 +103,9 @@ void test_parse(const std::string& input, int expected_type)
 void count_hints(const std::string& input, int num_expected)
 {
     int n = 0;
+    mxs::Buffer buffer(input.c_str(), input.size());
 
-    for (auto comment : get_all_comments(input.begin(), input.end()))
+    for (auto comment : get_all_comments(buffer.begin(), buffer.end()))
     {
         if (session.process_comment(comment.first, comment.second))
         {