Consistency; remove superfluous headers, forward decls

Make param to ExecQueryExplain a reference.

Author: pranavk

src/include/common/sql_node_visitor.h

@@ -21,6 +21,7 @@ class CreateFunctionStatement;
 class InsertStatement;
 class DeleteStatement;
 class DropStatement;
+class ExplainStatement;
 class PrepareStatement;
 class ExecuteStatement;
 class TransactionStatement;
@@ -80,6 +81,7 @@ class SqlNodeVisitor {
   virtual void Visit(parser::UpdateStatement *) {}
   virtual void Visit(parser::CopyStatement *) {}
   virtual void Visit(parser::AnalyzeStatement *){};
+  virtual void Visit(parser::ExplainStatement *){};
 
   virtual void Visit(expression::ComparisonExpression *expr);
   virtual void Visit(expression::AggregateExpression *expr);
@@ -93,8 +95,6 @@ class SqlNodeVisitor {
   virtual void Visit(expression::StarExpression *expr);
   virtual void Visit(expression::TupleValueExpression *expr);
   virtual void Visit(expression::SubqueryExpression *expr);
-
-
 };
 
 }  // namespace peloton

src/include/network/postgres_protocol_handler.h

@@ -23,7 +23,6 @@
 #include "common/portal.h"
 #include "common/statement.h"
 #include "common/statement_cache.h"
-#include "traffic_cop/traffic_cop.h"
 #include "protocol_handler.h"
 #include "traffic_cop/traffic_cop.h"
 
@@ -34,7 +33,7 @@ namespace peloton {
 
 namespace parser {
 class ExplainStatement;
-}
+}  // namespace parser
 
 namespace network {
 
@@ -168,7 +167,7 @@ class PostgresProtocolHandler : public ProtocolHandler {
 
   /* Execute a EXPLAIN query message */
   ResultType ExecQueryExplain(const std::string &query,
-                              parser::ExplainStatement *explain_stmt);
+                              parser::ExplainStatement &explain_stmt);
 
   /* Process the PARSE message of the extended query protocol */
   void ExecParseMessage(InputPacket *pkt);

src/include/parser/explain_statement.h

@@ -16,8 +16,6 @@
 
 namespace peloton {
 
-class SqlNodeVisitor;
-
 namespace parser {
 
 /**
@@ -29,7 +27,7 @@ class ExplainStatement : public SQLStatement {
   ExplainStatement() : SQLStatement(StatementType::EXPLAIN) {}
   virtual ~ExplainStatement() {}
 
-  virtual void Accept(UNUSED_ATTRIBUTE SqlNodeVisitor *v) override {}
+  void Accept(SqlNodeVisitor *v) override { v->Visit(this); }
 
   std::unique_ptr<parser::SQLStatement> real_sql_stmt;
 };

src/network/postgres_protocol_handler.cpp

@@ -33,7 +33,6 @@
 #include "traffic_cop/traffic_cop.h"
 #include "type/value.h"
 #include "type/value_factory.h"
-#include "network/marshal.h"
 #include "util/string_util.h"
 
 #define SSL_MESSAGE_VERNO 80877103
@@ -225,7 +224,7 @@ ProcessResult PostgresProtocolHandler::ExecQueryMessage(
     };
     case QueryType::QUERY_EXPLAIN: {
       auto status = ExecQueryExplain(
-          query, static_cast<parser::ExplainStatement *>(sql_stmt.get()));
+          query, static_cast<parser::ExplainStatement &>(*sql_stmt));
       ExecQueryMessageGetResult(status);
       return ProcessResult::COMPLETE;
     }
@@ -259,14 +258,11 @@ ProcessResult PostgresProtocolHandler::ExecQueryMessage(
 }
 
 ResultType PostgresProtocolHandler::ExecQueryExplain(
-    const std::string &query, parser::ExplainStatement *explain_stmt) {
-  PL_ASSERT(explain_stmt != nullptr);
-
+    const std::string &query, parser::ExplainStatement &explain_stmt) {
   std::string error_message;
   std::unique_ptr<parser::SQLStatementList> unnamed_sql_stmt_list(
       new parser::SQLStatementList());
-  unnamed_sql_stmt_list->PassInStatement(
-      std::move(explain_stmt->real_sql_stmt));
+  unnamed_sql_stmt_list->PassInStatement(std::move(explain_stmt.real_sql_stmt));
   auto stmt = traffic_cop_->PrepareStatement(
       "explain", query, std::move(unnamed_sql_stmt_list), error_message);
   ResultType status = ResultType::UNKNOWN;