add hexLit and binaryList support for LOAD DATA

[imtbkcat]

What problem does this PR solve?

TiDB cannot support LOAD DATA sql which fields terminated by hex expression.

load data local infile '/home/pingcap/jeff-test/merchant.dmp' into table `merchant` fields terminated by X'01'
2018/06/29 13:29:22.709 conn.go:481: [warning] [8448] dispatch error:

What is changed and how it works?

Add hexLit and binaryLit for FieldTerminator, and convert hex expression to string during parsing.

After:

mysql> load data local infile '~/1.csv' into table t_sp FIELDS TERMINATED BY X'2C2C2C2C' enclosed by '"';
Query OK, 3 rows affected (0.00 sec)
Records: 3  Deleted: 0  Skipped: 0  Warnings: 0

Check List

Tests

• Unit test

[codecov]

Codecov Report

Merging #365 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #365   +/-   ##
=======================================
  Coverage   50.44%   50.44%           
=======================================
  Files          31       31           
  Lines        6918     6918           
=======================================
  Hits         3490     3490           
  Misses       3069     3069           
  Partials      359      359

Impacted Files	Coverage Δ
parser.go	70.58% <ø> (ø)	⬆️
ast/misc.go	18.26% <ø> (ø)	⬆️

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[jackysp]

LGTM

[kennytm]

Could we use NewHexLiteral directly here?

parser/ast/misc.go

Lines 2035 to 2039 in 3b36f86

	// NewHexLiteral creates a types.HexLiteral value, it's provided by parser driver.
	var NewHexLiteral func(string) (interface{}, error)
	// NewBitLiteral creates a types.BitLiteral value, it's provided by parser driver.
	var NewBitLiteral func(string) (interface{}, error)

[imtbkcat]

ok

[imtbkcat]

But NewHexLiteral will return a n interface. type assert may be very complex

[kennytm]

🤔 Could we change the return type from interface{} to some real interface?

type BinaryLiteral interface {
    ToString() string
}

var NewHexLiteral func(string) (BinaryLiteral, error) 
var NewBitLiteral func(string) (BinaryLiteral, error) 

[imtbkcat]

It's a good idea.

[imtbkcat]

but it works will in TiDB😂

[kennytm]

Maybe try updating go.mod1 and go.sum1? 😂

[imtbkcat]

@kennytm how to upgrade go.mod in parser😂

[kennytm]

@imtbkcat Try to rename go.mod1 and go.sum1 to go.mod and go.sum, then do the regular update, then rename them back to go.mod1 and go.sum1 😂

[imtbkcat]

@kennytm fixed, PTAL

[kennytm]

LGTM