1 files changed, 87 insertions, 0 deletions
diff --git a/sql/opt_trace_context.h b/sql/opt_trace_context.h
new file mode 100644
index 00000000000..e5df16b1e3b
--- /dev/null
+++ b/sql/opt_trace_context.h
@@ -0,0 +1,87 @@
+#ifndef OPT_TRACE_CONTEXT_INCLUDED
+#define OPT_TRACE_CONTEXT_INCLUDED
+
+#include "sql_array.h"
+
+class Opt_trace_stmt;
+
+class Opt_trace_context
+{
+public:
+   Opt_trace_context();
+  ~Opt_trace_context();
+
+  void start(THD *thd, TABLE_LIST *tbl,
+             enum enum_sql_command sql_command,
+             const char *query,
+             size_t query_length,
+             const CHARSET_INFO *query_charset,
+             ulong max_mem_size_arg);
+  void end();
+  void set_query(const char *query, size_t length, const CHARSET_INFO *charset);
+  void delete_traces();
+  void set_allowed_mem_size(size_t mem_size);
+  size_t remaining_mem_size();
+
+private:
+  Opt_trace_stmt* top_trace()
+  {
+    return *(traces.front());
+  }
+
+public:
+
+  /*
+    This returns the top trace from the list of traces. This function
+    is used when we want to see the contents of the INFORMATION_SCHEMA.OPTIMIZER_TRACE
+  table.
+  */
+
+  Opt_trace_stmt* get_top_trace()
+  {
+    if (!traces.elements())
+      return NULL;
+    return top_trace();
+  }
+
+  /*
+    This returns the current trace, to which we are still writing and has not been finished
+  */
+
+  Json_writer* get_current_json();
+
+  bool empty()
+  {
+    return static_cast<uint>(traces.elements()) == 0;
+  }
+
+  bool is_started()
+  {
+    return current_trace && is_enabled();
+  }
+
+  bool disable_tracing_if_required();
+
+  bool enable_tracing_if_required();
+
+  bool is_enabled();
+
+  void missing_privilege();
+
+  static const char *flag_names[];
+  enum
+  {
+    FLAG_DEFAULT = 0,
+    FLAG_ENABLED = 1 << 0
+  };
+
+private:
+  /*
+    List of traces (currently it stores only 1 trace)
+  */
+  Dynamic_array<Opt_trace_stmt*> traces;
+  Opt_trace_stmt *current_trace;
+  size_t max_mem_size;
+};
+
+#endif /* OPT_TRACE_CONTEXT_INCLUDED */