From a69c936b44449ec82380dbd9f912ea4ec204d96c Mon Sep 17 00:00:00 2001
From: chertus <chertus@gmail.com>
Date: Wed, 29 Aug 2018 14:58:40 +0300
Subject: [PATCH] improve field visitors for UUID CLICKHOUSE-3249

---
 dbms/src/Common/FieldVisitors.cpp            | 21 +++-----------------
 dbms/src/IO/ReadHelpers.h                    |  5 +++++
 dbms/src/IO/WriteHelpers.h                   | 14 ++++++-------
 dbms/src/Interpreters/convertFieldToType.cpp | 13 ------------
 4 files changed, 15 insertions(+), 38 deletions(-)

diff --git a/dbms/src/Common/FieldVisitors.cpp b/dbms/src/Common/FieldVisitors.cpp
index 0bf90d03b70..e2b855c8f83 100644
--- a/dbms/src/Common/FieldVisitors.cpp
+++ b/dbms/src/Common/FieldVisitors.cpp
@@ -1,3 +1,4 @@
+#include <Core/UUID.h>
 #include <IO/ReadBuffer.h>
 #include <IO/WriteBuffer.h>
 #include <IO/ReadHelpers.h>
@@ -12,11 +13,6 @@
 namespace DB
 {
 
-UInt128 stringToUUID(const String & str)
-{
-    return parseFromString<UUID>(str);
-}
-
 template <typename T>
 static inline String formatQuoted(T x)
 {
@@ -50,14 +46,8 @@ String FieldVisitorDump::operator() (const Float64 & x) const { return formatQuo
 String FieldVisitorDump::operator() (const DecimalField<Decimal32> & x) const { return formatQuotedWithPrefix(x, "Decimal32_"); }
 String FieldVisitorDump::operator() (const DecimalField<Decimal64> & x) const { return formatQuotedWithPrefix(x, "Decimal64_"); }
 String FieldVisitorDump::operator() (const DecimalField<Decimal128> & x) const { return formatQuotedWithPrefix(x, "Decimal128_"); }
+String FieldVisitorDump::operator() (const UInt128 & x) const { return formatQuotedWithPrefix(UUID(x), "UUID_"); }
 
-String FieldVisitorDump::operator() (const UInt128 & x) const
-{
-    WriteBufferFromOwnString wb;
-    wb << "UInt128_" << x.low << "_" << x.high;
-    return wb.str();
-
-}
 
 String FieldVisitorDump::operator() (const String & x) const
 {
@@ -130,12 +120,7 @@ String FieldVisitorToString::operator() (const String & x) const { return format
 String FieldVisitorToString::operator() (const DecimalField<Decimal32> & x) const { return formatQuoted(x); }
 String FieldVisitorToString::operator() (const DecimalField<Decimal64> & x) const { return formatQuoted(x); }
 String FieldVisitorToString::operator() (const DecimalField<Decimal128> & x) const { return formatQuoted(x); }
-
-String FieldVisitorToString::operator() (const UInt128 & x) const
-{
-    /// Dummy implementation. There is no UInt128 literals in SQL.
-    return FieldVisitorDump()(x);
-}
+String FieldVisitorToString::operator() (const UInt128 & x) const { return formatQuoted(UUID(x)); }
 
 String FieldVisitorToString::operator() (const Array & x) const
 {
diff --git a/dbms/src/IO/ReadHelpers.h b/dbms/src/IO/ReadHelpers.h
index 4bf3771c72f..0fbc4a99e91 100644
--- a/dbms/src/IO/ReadHelpers.h
+++ b/dbms/src/IO/ReadHelpers.h
@@ -561,6 +561,11 @@ inline T parseFromString(const String & str)
     return parse<T>(str.data(), str.size());
 }
 
+inline UInt128 stringToUUID(const String & str)
+{
+    return parseFromString<UUID>(str);
+}
+
 
 template <typename ReturnType = void>
 ReturnType readDateTimeTextFallback(time_t & datetime, ReadBuffer & buf, const DateLUTImpl & date_lut);
diff --git a/dbms/src/IO/WriteHelpers.h b/dbms/src/IO/WriteHelpers.h
index d840139777d..d58fd784c6b 100644
--- a/dbms/src/IO/WriteHelpers.h
+++ b/dbms/src/IO/WriteHelpers.h
@@ -704,13 +704,7 @@ inline void writeText(const char * x, size_t size, WriteBuffer & buf) { writeEsc
 inline void writeText(const LocalDate & x, WriteBuffer & buf) { writeDateText(x, buf); }
 inline void writeText(const LocalDateTime & x, WriteBuffer & buf) { writeDateTimeText(x, buf); }
 inline void writeText(const UUID & x, WriteBuffer & buf) { writeUUIDText(x, buf); }
-inline void writeText(const UInt128 &, WriteBuffer &)
-{
-    /** Because UInt128 isn't a natural type, without arithmetic operator and only use as an intermediary type -for UUID-
-     *  it should never arrive here. But because we used the DataTypeNumber class we should have at least a definition of it.
-     */
-    throw Exception("UInt128 cannot be write as a text", ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT);
-}
+inline void writeText(const UInt128 & x, WriteBuffer & buf) { writeText(UUID(x), buf); }
 
 template <typename T> inline T decimalScaleMultiplier(UInt32 scale);
 template <> inline Int32 decimalScaleMultiplier<Int32>(UInt32 scale) { return common::exp10_i32(scale); }
@@ -763,6 +757,12 @@ inline void writeQuoted(const LocalDateTime & x, WriteBuffer & buf)
     writeChar('\'', buf);
 }
 
+inline void writeQuoted(const UUID & x, WriteBuffer & buf)
+{
+    writeChar('\'', buf);
+    writeText(x, buf);
+    writeChar('\'', buf);
+}
 
 /// String, date, datetime are in double quotes with C-style escaping. Numbers - without.
 template <typename T>
diff --git a/dbms/src/Interpreters/convertFieldToType.cpp b/dbms/src/Interpreters/convertFieldToType.cpp
index 36f5063ac00..22e688f150b 100644
--- a/dbms/src/Interpreters/convertFieldToType.cpp
+++ b/dbms/src/Interpreters/convertFieldToType.cpp
@@ -138,19 +138,6 @@ UInt64 stringToDateTime(const String & s)
     return UInt64(date_time);
 }
 
-UInt128 stringToUUID(const String & s)
-{
-    ReadBufferFromString in(s);
-    UUID uuid;
-
-    readText(uuid, in);
-    if (!in.eof())
-        throw Exception("String is too long for UUID: " + s);
-
-    return UInt128(uuid);
-}
-
-
 Field convertFieldToTypeImpl(const Field & src, const IDataType & type)
 {
     if (type.isValueRepresentedByNumber())