From 901294d35206d52c29f876dda7658a4d8252d191 Mon Sep 17 00:00:00 2001
From: Maksim Kita <kitaetoya@gmail.com>
Date: Wed, 25 Oct 2023 21:41:26 +0300
Subject: [PATCH] Fixed code review issues

---
 src/Common/escapeString.cpp                      | 16 ++++++++++++++++
 src/Common/escapeString.h                        | 10 ++++++++++
 src/Interpreters/InterpreterShowColumnsQuery.cpp |  9 +++------
 src/Interpreters/InterpreterShowIndexesQuery.cpp | 12 +++---------
 src/Interpreters/InterpreterShowSettingQuery.cpp |  7 ++-----
 src/Parsers/ParserShowSettingQuery.cpp           |  3 ---
 src/Parsers/ParserShowSettingQuery.h             |  6 +++---
 .../02905_show_setting_query.reference           |  1 +
 .../0_stateless/02905_show_setting_query.sql     |  5 +++++
 9 files changed, 43 insertions(+), 26 deletions(-)
 create mode 100644 src/Common/escapeString.cpp
 create mode 100644 src/Common/escapeString.h

diff --git a/src/Common/escapeString.cpp b/src/Common/escapeString.cpp
new file mode 100644
index 00000000000..621726d38ac
--- /dev/null
+++ b/src/Common/escapeString.cpp
@@ -0,0 +1,16 @@
+#include <Common/escapeString.h>
+
+#include <IO/WriteBufferFromString.h>
+#include <IO/WriteHelpers.h>
+
+namespace DB
+{
+
+String escapeString(std::string_view value)
+{
+    WriteBufferFromOwnString buf;
+    writeEscapedString(value, buf);
+    return buf.str();
+}
+
+}
diff --git a/src/Common/escapeString.h b/src/Common/escapeString.h
new file mode 100644
index 00000000000..0018296889c
--- /dev/null
+++ b/src/Common/escapeString.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <base/types.h>
+
+namespace DB
+{
+
+String escapeString(std::string_view value);
+
+}
diff --git a/src/Interpreters/InterpreterShowColumnsQuery.cpp b/src/Interpreters/InterpreterShowColumnsQuery.cpp
index d14a36ef7e1..c8fb64e37f2 100644
--- a/src/Interpreters/InterpreterShowColumnsQuery.cpp
+++ b/src/Interpreters/InterpreterShowColumnsQuery.cpp
@@ -1,6 +1,7 @@
 #include <Interpreters/InterpreterShowColumnsQuery.h>
 
 #include <Common/quoteString.h>
+#include <Common/escapeString.h>
 #include <IO/Operators.h>
 #include <IO/WriteBufferFromString.h>
 #include <Parsers/ASTShowColumnsQuery.h>
@@ -31,12 +32,8 @@ String InterpreterShowColumnsQuery::getRewrittenQuery()
 
     WriteBufferFromOwnString buf_database;
     String resolved_database = getContext()->resolveDatabase(query.database);
-    writeEscapedString(resolved_database, buf_database);
-    String database = buf_database.str();
-
-    WriteBufferFromOwnString buf_table;
-    writeEscapedString(query.table, buf_table);
-    String table = buf_table.str();
+    String database = escapeString(resolved_database);
+    String table = escapeString(query.table);
 
     String rewritten_query;
     if (use_mysql_types)
diff --git a/src/Interpreters/InterpreterShowIndexesQuery.cpp b/src/Interpreters/InterpreterShowIndexesQuery.cpp
index 9b36f1496e7..63cda814683 100644
--- a/src/Interpreters/InterpreterShowIndexesQuery.cpp
+++ b/src/Interpreters/InterpreterShowIndexesQuery.cpp
@@ -1,6 +1,7 @@
 #include <Interpreters/InterpreterShowIndexesQuery.h>
 
 #include <Common/quoteString.h>
+#include <Common/escapeString.h>
 #include <IO/Operators.h>
 #include <IO/WriteBufferFromString.h>
 #include <Parsers/ASTShowIndexesQuery.h>
@@ -23,16 +24,9 @@ InterpreterShowIndexesQuery::InterpreterShowIndexesQuery(const ASTPtr & query_pt
 String InterpreterShowIndexesQuery::getRewrittenQuery()
 {
     const auto & query = query_ptr->as<ASTShowIndexesQuery &>();
-
-    WriteBufferFromOwnString buf_table;
-    writeEscapedString(query.table, buf_table);
-    String table = buf_table.str();
-
-    WriteBufferFromOwnString buf_database;
+    String table = escapeString(query.table);
     String resolved_database = getContext()->resolveDatabase(query.database);
-    writeEscapedString(resolved_database, buf_database);
-    String database = buf_database.str();
-
+    String database = escapeString(resolved_database);
     String where_expression = query.where_expression ? fmt::format("WHERE ({})", query.where_expression) : "";
 
     String rewritten_query = fmt::format(R"(
diff --git a/src/Interpreters/InterpreterShowSettingQuery.cpp b/src/Interpreters/InterpreterShowSettingQuery.cpp
index aa3556a8837..7567e77d28f 100644
--- a/src/Interpreters/InterpreterShowSettingQuery.cpp
+++ b/src/Interpreters/InterpreterShowSettingQuery.cpp
@@ -1,10 +1,7 @@
 #include <Interpreters/InterpreterShowSettingQuery.h>
 
-#include <Common/quoteString.h>
-#include <IO/Operators.h>
-#include <IO/WriteBufferFromString.h>
+#include <Common/escapeString.h>
 #include <Parsers/ASTShowSettingQuery.h>
-#include <Parsers/formatAST.h>
 #include <Interpreters/Context.h>
 #include <Interpreters/executeQuery.h>
 
@@ -23,7 +20,7 @@ InterpreterShowSettingQuery::InterpreterShowSettingQuery(const ASTPtr & query_pt
 String InterpreterShowSettingQuery::getRewrittenQuery()
 {
     const auto & query = query_ptr->as<ASTShowSettingQuery &>();
-    return fmt::format(R"(SELECT value FROM system.settings WHERE name = '{0}')", query.getSettingName());
+    return fmt::format(R"(SELECT value FROM system.settings WHERE name = '{0}')", escapeString(query.getSettingName()));
 }
 
 
diff --git a/src/Parsers/ParserShowSettingQuery.cpp b/src/Parsers/ParserShowSettingQuery.cpp
index 92bed51b688..2586cbdfb43 100644
--- a/src/Parsers/ParserShowSettingQuery.cpp
+++ b/src/Parsers/ParserShowSettingQuery.cpp
@@ -1,13 +1,10 @@
 #include <Parsers/ParserShowSettingQuery.h>
 
 #include <Parsers/ASTIdentifier_fwd.h>
-#include <Parsers/ASTLiteral.h>
 #include <Parsers/ASTShowSettingQuery.h>
 #include <Parsers/CommonParsers.h>
 #include <Parsers/ExpressionElementParsers.h>
-#include <Parsers/ExpressionListParsers.h>
 
-#include <boost/algorithm/string.hpp>
 
 namespace DB
 {
diff --git a/src/Parsers/ParserShowSettingQuery.h b/src/Parsers/ParserShowSettingQuery.h
index 56c835eb349..ef166133d09 100644
--- a/src/Parsers/ParserShowSettingQuery.h
+++ b/src/Parsers/ParserShowSettingQuery.h
@@ -5,9 +5,9 @@
 namespace DB
 {
 
-/** Parses queries of the form
- * SHOW SETTING setting_name
- */
+/** Parses queries of the form:
+  * SHOW SETTING [setting_name]
+  */
 class ParserShowSettingQuery : public IParserBase
 {
 protected:
diff --git a/tests/queries/0_stateless/02905_show_setting_query.reference b/tests/queries/0_stateless/02905_show_setting_query.reference
index d00491fd7e5..1191247b6d9 100644
--- a/tests/queries/0_stateless/02905_show_setting_query.reference
+++ b/tests/queries/0_stateless/02905_show_setting_query.reference
@@ -1 +1,2 @@
 1
+2
diff --git a/tests/queries/0_stateless/02905_show_setting_query.sql b/tests/queries/0_stateless/02905_show_setting_query.sql
index ee7c9379146..bbbb1a7e237 100644
--- a/tests/queries/0_stateless/02905_show_setting_query.sql
+++ b/tests/queries/0_stateless/02905_show_setting_query.sql
@@ -1,2 +1,7 @@
 SET max_threads = 1;
 SHOW SETTING max_threads;
+
+SET max_threads = 2;
+SHOW SETTING max_threads;
+
+SHOW SETTING `max_threads' OR name = 'max_memory_usage`;