1 files changed, 135 insertions, 0 deletions
diff --git a/sql/opt_trace_context.h b/sql/opt_trace_context.h
new file mode 100644
index 00000000..f578a0c6
--- /dev/null
+++ b/sql/opt_trace_context.h
@@ -0,0 +1,135 @@
+#ifndef OPT_TRACE_CONTEXT_INCLUDED
+#define OPT_TRACE_CONTEXT_INCLUDED
+
+#include "sql_array.h"
+
+class Opt_trace_context;
+struct Opt_trace_info;
+class Json_writer;
+
+class Opt_trace_stmt {
+ public:
+  /**
+     Constructor, starts a trace for information_schema and dbug.
+     @param  ctx_arg          context
+  */
+  Opt_trace_stmt(Opt_trace_context *ctx_arg);
+  ~Opt_trace_stmt();
+  void set_query(const char *query_ptr, size_t length, const CHARSET_INFO *charset);
+  void open_struct(const char *key, char opening_bracket);
+  void close_struct(const char *saved_key, char closing_bracket);
+  void fill_info(Opt_trace_info* info);
+  void add(const char *key, char *opening_bracket, size_t val_length);
+  Json_writer* get_current_json() {return current_json;}
+  void missing_privilege();
+  void disable_tracing_for_children();
+  void enable_tracing_for_children();
+  bool is_enabled()
+  {
+   return I_S_disabled == 0;
+  }
+  void set_allowed_mem_size(size_t mem_size);
+  size_t get_length();
+  size_t get_truncated_bytes();
+  bool get_missing_priv() { return missing_priv; }
+
+private:
+  Opt_trace_context *ctx;
+  String query;  // store the query sent by the user
+  Json_writer *current_json; // stores the trace
+  bool missing_priv;  ///< whether user lacks privilege to see this trace
+  /*
+    0 <=> this trace should be in information_schema.
+  !=0 tracing is disabled, this currently happens when we want to trace a
+      sub-statement. For now traces are only collect for the top statement
+      not for the sub-statments.
+  */
+  uint I_S_disabled;
+};
+
+
+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()
+  {
+    if (!is_started())
+      return NULL;
+    return current_trace->get_current_json();
+  }
+
+  bool empty()
+  {
+    return static_cast<uint>(traces.elements()) == 0;
+  }
+
+  bool is_started()
+  {
+    return current_trace && 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 */