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support like escape #360

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merged 6 commits into from
Oct 13, 2015
Merged

support like escape #360

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d32e4f5
*: support like escape
siddontang Oct 12, 2015
320dca9
parser: fix S/R conflict.
siddontang Oct 12, 2015
001a9f9
*: merge master and fix conflict
siddontang Oct 12, 2015
6c9cf06
parser: add test
siddontang Oct 12, 2015
9e8ce41
expression: fix escape string format.
siddontang Oct 12, 2015
213b0b9
parser: Address comment
siddontang Oct 13, 2015
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23 changes: 17 additions & 6 deletions expression/like.go
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,8 @@ type PatternLike struct {
patTypes []byte
// Not is true, the expression is "not like".
Not bool
// Escape is the special escaped character, default is \.
Escape byte
}

// Clone implements the Expression Clone interface.
Expand All @@ -57,6 +59,7 @@ func (p *PatternLike) Clone() Expression {
patChars: p.patChars,
patTypes: p.patTypes,
Not: p.Not,
Escape: p.Escape,
}
}

Expand All @@ -67,6 +70,9 @@ func (p *PatternLike) IsStatic() bool {

// String implements the Expression String interface.
func (p *PatternLike) String() string {
if p.Escape != '\\' {
return fmt.Sprintf("%s LIKE %s ESCAPE '%c'", p.Expr, p.Pattern, p.Escape)
}
return fmt.Sprintf("%s LIKE %s", p.Expr, p.Pattern)
}

Expand Down Expand Up @@ -104,7 +110,7 @@ func (p *PatternLike) Eval(ctx context.Context, args map[interface{}]interface{}
default:
return nil, errors.Errorf("Pattern should be string or []byte in LIKE: %v (Value of type %T)", pattern, pattern)
}
p.patChars, p.patTypes = compilePattern(spattern)
p.patChars, p.patTypes = compilePattern(spattern, p.Escape)
}

match := doMatch(sexpr, p.patChars, p.patTypes)
Expand All @@ -120,7 +126,7 @@ func (p *PatternLike) Accept(v Visitor) (Expression, error) {
}

// handle escapes and wild cards convert pattern characters and pattern types,
func compilePattern(pattern string) (patChars, patTypes []byte) {
func compilePattern(pattern string, escape byte) (patChars, patTypes []byte) {
var lastAny bool
patChars = make([]byte, len(pattern))
patTypes = make([]byte, len(pattern))
Expand All @@ -129,18 +135,23 @@ func compilePattern(pattern string) (patChars, patTypes []byte) {
var tp byte
var c = pattern[i]
switch c {
case '\\':
case escape:
lastAny = false
tp = patMatch
if i < len(pattern)-1 {
i++
c = pattern[i]
if c == '\\' || c == '_' || c == '%' {
if c == escape || c == '_' || c == '%' {
// valid escape.
} else {
// invalid escape, fall back to literal back slash
// invalid escape, fall back to escape byte
// mysql will treat escape character as the origin value even
// the escape sequence is invalid in Go or C.
// e.g, \m is invalid in Go, but in MySQL we will get "m" for select '\m'.
// Following case is correct just for escape \, not for others like +.
// TODO: add more checks for other escapes.
i--
c = '\\'
c = escape
}
}
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How about i==len(pattern)-1 ?

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I just use the old code here, which just seems using the origin escape character directly.
I have added a comment that we will add more tests later.

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If the escape is the last character in the pattern, the match type would be exact match.

case '_':
Expand Down
58 changes: 34 additions & 24 deletions expression/like_test.go
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Expand Up @@ -27,34 +27,40 @@ func (*testLikeSuite) TestLike(c *C) {
tbl := []struct {
pattern string
input string
escape byte
match bool
}{
{"", "a", false},
{"a", "a", true},
{"a", "b", false},
{"aA", "aA", true},
{"_", "a", true},
{"_", "ab", false},
{"__", "b", false},
{"_ab", "AAB", true},
{"%", "abcd", true},
{"%", "", true},
{"%a", "AAA", true},
{"%b", "AAA", false},
{"b%", "BBB", true},
{"%a%", "BBB", false},
{"%a%", "BAB", true},
{"a%", "BBB", false},
{`\%a`, `%a`, true},
{`\%a`, `aa`, false},
{`\_a`, `_a`, true},
{`\_a`, `aa`, false},
{`\\_a`, `\xa`, true},
{`\a\b`, `\a\b`, true},
{"%%_", `abc`, true},
{"", "a", '\\', false},
{"a", "a", '\\', true},
{"a", "b", '\\', false},
{"aA", "aA", '\\', true},
{"_", "a", '\\', true},
{"_", "ab", '\\', false},
{"__", "b", '\\', false},
{"_ab", "AAB", '\\', true},
{"%", "abcd", '\\', true},
{"%", "", '\\', true},
{"%a", "AAA", '\\', true},
{"%b", "AAA", '\\', false},
{"b%", "BBB", '\\', true},
{"%a%", "BBB", '\\', false},
{"%a%", "BAB", '\\', true},
{"a%", "BBB", '\\', false},
{`\%a`, `%a`, '\\', true},
{`\%a`, `aa`, '\\', false},
{`\_a`, `_a`, '\\', true},
{`\_a`, `aa`, '\\', false},
{`\\_a`, `\xa`, '\\', true},
{`\a\b`, `\a\b`, '\\', true},
{"%%_", `abc`, '\\', true},
{`+_a`, `_a`, '+', true},
{`+%a`, `%a`, '+', true},
{`\%a`, `%a`, '+', false},
{`++a`, `+a`, '+', true},
{`++_a`, `+xa`, '+', true},
}
for _, v := range tbl {
patChars, patTypes := compilePattern(v.pattern)
patChars, patTypes := compilePattern(v.pattern, v.escape)
match := doMatch(v.input, patChars, patTypes)
c.Assert(match, Equals, v.match, Commentf("%v", v))
}
Expand All @@ -68,6 +74,8 @@ func (*testLikeSuite) TestEval(c *C) {
Pattern: &Value{
Val: "aA",
},

Escape: '\\',
}
cloned := pattern.Clone()
pattern = cloned.(*PatternLike)
Expand Down Expand Up @@ -107,13 +115,15 @@ func (*testLikeSuite) TestEval(c *C) {
pattern = &PatternLike{
Expr: mockExpr{isStatic: true, val: "slien"},
Pattern: mockExpr{isStatic: true, val: []byte("%E%")},
Escape: '\\',
}
v, err := pattern.Eval(nil, nil)
c.Assert(err, IsNil)
c.Assert(v, IsTrue)
pattern = &PatternLike{
Expr: mockExpr{isStatic: true, val: "slin"},
Pattern: mockExpr{isStatic: true, val: []byte("%E%")},
Escape: '\\',
}
v, err = pattern.Eval(nil, nil)
c.Assert(err, IsNil)
Expand Down
31 changes: 28 additions & 3 deletions parser/parser.y
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Original file line number Diff line number Diff line change
Expand Up @@ -134,6 +134,7 @@ import (
engines "ENGINES"
enum "ENUM"
eq "="
escape "ESCAPE"
execute "EXECUTE"
exists "EXISTS"
explain "EXPLAIN"
Expand Down Expand Up @@ -428,6 +429,7 @@ import (
JoinTable "join table"
JoinType "join type"
KeyOrIndex "{KEY|INDEX}"
LikeEscapeOpt "like escape option"
LimitClause "LIMIT clause"
Literal "literal value"
logAnd "logical and operator"
Expand Down Expand Up @@ -590,6 +592,8 @@ import (
%precedence '('
%precedence lowerThanQuick
%precedence quick
%precedence lowerThanEscape
%precedence escape
%precedence lowerThanComma
%precedence ','

Expand Down Expand Up @@ -1510,9 +1514,20 @@ Factor1:
return 1
}
}
| PrimaryFactor NotOpt "LIKE" PrimaryExpression
| PrimaryFactor NotOpt "LIKE" PrimaryExpression LikeEscapeOpt
{
$$ = &expression.PatternLike{Expr: $1.(expression.Expression), Pattern: $4.(expression.Expression), Not: $2.(bool)}
escape := $5.(string)
if len(escape) > 1 {
yylex.(*lexer).errf("Incorrect arguments %s to ESCAPE", escape)
return 1
} else if len(escape) == 0 {
escape = "\\"
}
$$ = &expression.PatternLike{
Expr: $1.(expression.Expression),
Pattern: $4.(expression.Expression),
Not: $2.(bool),
Escape: escape[0]}
}
| PrimaryFactor NotOpt RegexpSym PrimaryExpression
{
Expand All @@ -1524,6 +1539,16 @@ RegexpSym:
"REGEXP"
| "RLIKE"

LikeEscapeOpt:
%prec lowerThanEscape
{
$$ = "\\"
}
| "ESCAPE" stringLit
{
$$ = $2
}

NotOpt:
{
$$ = false
Expand Down Expand Up @@ -1666,7 +1691,7 @@ UnReservedKeyword:
| "START" | "GLOBAL" | "TABLES"| "TEXT" | "TIME" | "TIMESTAMP" | "TRANSACTION" | "TRUNCATE" | "UNKNOWN"
| "VALUE" | "WARNINGS" | "YEAR" | "MODE" | "WEEK" | "ANY" | "SOME" | "USER" | "IDENTIFIED" | "COLLATION"
| "COMMENT" | "AVG_ROW_LENGTH" | "CONNECTION" | "CHECKSUM" | "COMPRESSION" | "KEY_BLOCK_SIZE" | "MAX_ROWS" | "MIN_ROWS"
| "NATIONAL" | "ROW" | "QUARTER"
| "NATIONAL" | "ROW" | "QUARTER" | "ESCAPE"

NotKeywordToken:
"ABS" | "COALESCE" | "CONCAT" | "CONCAT_WS" | "COUNT" | "DAY" | "DAYOFMONTH" | "DAYOFWEEK" | "DAYOFYEAR" | "FOUND_ROWS" | "GROUP_CONCAT"
Expand Down
14 changes: 13 additions & 1 deletion parser/parser_test.go
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Expand Up @@ -58,7 +58,7 @@ func (s *testParserSuite) TestSimple(c *C) {
"start", "global", "tables", "text", "time", "timestamp", "transaction", "truncate", "unknown",
"value", "warnings", "year", "now", "substring", "mode", "any", "some", "user", "identified",
"collation", "comment", "avg_row_length", "checksum", "compression", "connection", "key_block_size",
"max_rows", "min_rows", "national", "row", "quarter",
"max_rows", "min_rows", "national", "row", "quarter", "escape",
}
for _, kw := range unreservedKws {
src := fmt.Sprintf("SELECT %s FROM tbl;", kw)
Expand Down Expand Up @@ -578,3 +578,15 @@ func (s *testParserSuite) TestUnion(c *C) {
}
s.RunTest(c, table)
}

func (s *testParserSuite) TestLikeEscape(c *C) {
table := []testCase{
// For like escape
{`select "abc_" like "abc\\_" escape ''`, true},
{`select "abc_" like "abc\\_" escape '\\'`, true},
{`select "abc_" like "abc\\_" escape '||'`, false},
{`select "abc" like "escape" escape '+'`, true},
}

s.RunTest(c, table)
}
3 changes: 3 additions & 0 deletions parser/scanner.l
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Original file line number Diff line number Diff line change
Expand Up @@ -304,6 +304,7 @@ else {e}{l}{s}{e}
end {e}{n}{d}
engine {e}{n}{g}{i}{n}{e}
engines {e}{n}{g}{i}{n}{e}{s}
escape {e}{s}{c}{a}{p}{e}
execute {e}{x}{e}{c}{u}{t}{e}
exists {e}{x}{i}{s}{t}{s}
explain {e}{x}{p}{l}{a}{i}{n}
Expand Down Expand Up @@ -667,6 +668,8 @@ year_month {y}{e}{a}{r}_{m}{o}{n}{t}{h}
{execute} lval.item = string(l.val)
return execute
{enum} return enum
{escape} lval.item = string(l.val)
return escape
{exists} return exists
{explain} return explain
{extract} lval.item = string(l.val)
Expand Down