From 738fa0ac30ac1185a56b941565a09803a314642d Mon Sep 17 00:00:00 2001
From: Eduard S <eduard@iden3.io>
Date: Wed, 18 Nov 2020 12:54:45 +0100
Subject: [PATCH] Update SQL types, improve SQL *big.Int

- In SQL Tables, set rollup_vars.forge_l1_timeout to BIGINT (instead of BYTEA)
- In "bigint" encoding/decoding used with meddler, store the *big.Int as raw
  bytes, instead of base64 to be more space efficient
---
 apitypes/apitypes.go   | 28 +++++++---------------------
 db/migrations/0001.sql |  2 +-
 db/utils.go            | 35 +++++++++++------------------------
 3 files changed, 19 insertions(+), 46 deletions(-)

diff --git a/apitypes/apitypes.go b/apitypes/apitypes.go
index db4b624..b8753ef 100644
--- a/apitypes/apitypes.go
+++ b/apitypes/apitypes.go
@@ -33,25 +33,12 @@ func NewBigIntStr(bigInt *big.Int) *BigIntStr {
 
 // Scan implements Scanner for database/sql
 func (b *BigIntStr) Scan(src interface{}) error {
-	// decode base64 src
-	var decoded []byte
-	var err error
-	if srcStr, ok := src.(string); ok {
-		// src is a string
-		decoded, err = base64.StdEncoding.DecodeString(srcStr)
-	} else if srcBytes, ok := src.([]byte); ok {
-		// src is []byte
-		decoded, err = base64.StdEncoding.DecodeString(string(srcBytes))
-	} else {
-		// unexpected src
+	srcBytes, ok := src.([]byte)
+	if !ok {
 		return fmt.Errorf("can't scan %T into apitypes.BigIntStr", src)
 	}
-	if err != nil {
-		return err
-	}
-	// decoded bytes to *big.Int
-	bigInt := &big.Int{}
-	bigInt = bigInt.SetBytes(decoded)
+	// bytes to *big.Int
+	bigInt := new(big.Int).SetBytes(srcBytes)
 	// *big.Int to BigIntStr
 	bigIntStr := NewBigIntStr(bigInt)
 	if bigIntStr == nil {
@@ -64,13 +51,12 @@ func (b *BigIntStr) Scan(src interface{}) error {
 // Value implements valuer for database/sql
 func (b BigIntStr) Value() (driver.Value, error) {
 	// string to *big.Int
-	bigInt := &big.Int{}
-	bigInt, ok := bigInt.SetString(string(b), 10)
+	bigInt, ok := new(big.Int).SetString(string(b), 10)
 	if !ok || bigInt == nil {
 		return nil, errors.New("invalid representation of a *big.Int")
 	}
-	// *big.Int to base64
-	return base64.StdEncoding.EncodeToString(bigInt.Bytes()), nil
+	// *big.Int to bytes
+	return bigInt.Bytes(), nil
 }
 
 // StrBigInt is used to unmarshal BigIntStr directly into an alias of big.Int
diff --git a/db/migrations/0001.sql b/db/migrations/0001.sql
index 93d0f85..b237eee 100644
--- a/db/migrations/0001.sql
+++ b/db/migrations/0001.sql
@@ -526,7 +526,7 @@ FOR EACH ROW EXECUTE PROCEDURE forge_l1_user_txs();
 CREATE TABLE rollup_vars (
     eth_block_num BIGINT PRIMARY KEY REFERENCES block (eth_block_num) ON DELETE CASCADE,
     fee_add_token BYTEA NOT NULL,
-    forge_l1_timeout BYTEA NOT NULL,
+    forge_l1_timeout BIGINT NOT NULL,
     withdrawal_delay BIGINT NOT NULL,
     buckets BYTEA
 );
diff --git a/db/utils.go b/db/utils.go
index 8f3e1e1..0e3a594 100644
--- a/db/utils.go
+++ b/db/utils.go
@@ -1,7 +1,6 @@
 package db
 
 import (
-	"encoding/base64"
 	"fmt"
 	"math/big"
 	"reflect"
@@ -95,14 +94,8 @@ func (b BigIntMeddler) PostRead(fieldPtr, scanTarget interface{}) error {
 	if ptr == nil {
 		return fmt.Errorf("BigIntMeddler.PostRead: nil pointer")
 	}
-
-	data, err := base64.StdEncoding.DecodeString(*ptr)
-	if err != nil {
-		return fmt.Errorf("big.Int decode error: %v", err)
-	}
 	field := fieldPtr.(**big.Int)
-	*field = new(big.Int).SetBytes(data)
-
+	*field = new(big.Int).SetBytes([]byte(*ptr))
 	return nil
 }
 
@@ -110,9 +103,7 @@ func (b BigIntMeddler) PostRead(fieldPtr, scanTarget interface{}) error {
 func (b BigIntMeddler) PreWrite(fieldPtr interface{}) (saveValue interface{}, err error) {
 	field := fieldPtr.(*big.Int)
 
-	str := base64.StdEncoding.EncodeToString(field.Bytes())
-
-	return str, nil
+	return field.Bytes(), nil
 }
 
 // BigIntNullMeddler encodes or decodes the field value to or from JSON
@@ -125,23 +116,19 @@ func (b BigIntNullMeddler) PreRead(fieldAddr interface{}) (scanTarget interface{
 
 // PostRead is called after a Scan operation for fields that have the BigIntNullMeddler
 func (b BigIntNullMeddler) PostRead(fieldPtr, scanTarget interface{}) error {
-	sv := reflect.ValueOf(scanTarget)
-	if sv.Elem().IsNil() {
+	field := fieldPtr.(**big.Int)
+	ptrPtr := scanTarget.(*interface{})
+	if *ptrPtr == nil {
 		// null column, so set target to be zero value
-		fv := reflect.ValueOf(fieldPtr)
-		fv.Elem().Set(reflect.Zero(fv.Elem().Type()))
+		*field = nil
 		return nil
 	}
 	// not null
-	encoded := new([]byte)
-	refEnc := reflect.ValueOf(encoded)
-	refEnc.Elem().Set(sv.Elem().Elem())
-	data, err := base64.StdEncoding.DecodeString(string(*encoded))
-	if err != nil {
-		return fmt.Errorf("big.Int decode error: %v", err)
+	ptr := (*ptrPtr).([]byte)
+	if ptr == nil {
+		return fmt.Errorf("BigIntMeddler.PostRead: nil pointer")
 	}
-	field := fieldPtr.(**big.Int)
-	*field = new(big.Int).SetBytes(data)
+	*field = new(big.Int).SetBytes(ptr)
 	return nil
 }
 
@@ -151,7 +138,7 @@ func (b BigIntNullMeddler) PreWrite(fieldPtr interface{}) (saveValue interface{}
 	if field == nil {
 		return nil, nil
 	}
-	return base64.StdEncoding.EncodeToString(field.Bytes()), nil
+	return field.Bytes(), nil
 }
 
 // SliceToSlicePtrs converts any []Foo to []*Foo