mirror of https://github.com/k3s-io/k3s
604 lines
15 KiB
Go
604 lines
15 KiB
Go
package jmespath
|
|
|
|
import (
|
|
"encoding/json"
|
|
"fmt"
|
|
"strconv"
|
|
"strings"
|
|
)
|
|
|
|
type astNodeType int
|
|
|
|
//go:generate stringer -type astNodeType
|
|
const (
|
|
ASTEmpty astNodeType = iota
|
|
ASTComparator
|
|
ASTCurrentNode
|
|
ASTExpRef
|
|
ASTFunctionExpression
|
|
ASTField
|
|
ASTFilterProjection
|
|
ASTFlatten
|
|
ASTIdentity
|
|
ASTIndex
|
|
ASTIndexExpression
|
|
ASTKeyValPair
|
|
ASTLiteral
|
|
ASTMultiSelectHash
|
|
ASTMultiSelectList
|
|
ASTOrExpression
|
|
ASTAndExpression
|
|
ASTNotExpression
|
|
ASTPipe
|
|
ASTProjection
|
|
ASTSubexpression
|
|
ASTSlice
|
|
ASTValueProjection
|
|
)
|
|
|
|
// ASTNode represents the abstract syntax tree of a JMESPath expression.
|
|
type ASTNode struct {
|
|
nodeType astNodeType
|
|
value interface{}
|
|
children []ASTNode
|
|
}
|
|
|
|
func (node ASTNode) String() string {
|
|
return node.PrettyPrint(0)
|
|
}
|
|
|
|
// PrettyPrint will pretty print the parsed AST.
|
|
// The AST is an implementation detail and this pretty print
|
|
// function is provided as a convenience method to help with
|
|
// debugging. You should not rely on its output as the internal
|
|
// structure of the AST may change at any time.
|
|
func (node ASTNode) PrettyPrint(indent int) string {
|
|
spaces := strings.Repeat(" ", indent)
|
|
output := fmt.Sprintf("%s%s {\n", spaces, node.nodeType)
|
|
nextIndent := indent + 2
|
|
if node.value != nil {
|
|
if converted, ok := node.value.(fmt.Stringer); ok {
|
|
// Account for things like comparator nodes
|
|
// that are enums with a String() method.
|
|
output += fmt.Sprintf("%svalue: %s\n", strings.Repeat(" ", nextIndent), converted.String())
|
|
} else {
|
|
output += fmt.Sprintf("%svalue: %#v\n", strings.Repeat(" ", nextIndent), node.value)
|
|
}
|
|
}
|
|
lastIndex := len(node.children)
|
|
if lastIndex > 0 {
|
|
output += fmt.Sprintf("%schildren: {\n", strings.Repeat(" ", nextIndent))
|
|
childIndent := nextIndent + 2
|
|
for _, elem := range node.children {
|
|
output += elem.PrettyPrint(childIndent)
|
|
}
|
|
}
|
|
output += fmt.Sprintf("%s}\n", spaces)
|
|
return output
|
|
}
|
|
|
|
var bindingPowers = map[tokType]int{
|
|
tEOF: 0,
|
|
tUnquotedIdentifier: 0,
|
|
tQuotedIdentifier: 0,
|
|
tRbracket: 0,
|
|
tRparen: 0,
|
|
tComma: 0,
|
|
tRbrace: 0,
|
|
tNumber: 0,
|
|
tCurrent: 0,
|
|
tExpref: 0,
|
|
tColon: 0,
|
|
tPipe: 1,
|
|
tOr: 2,
|
|
tAnd: 3,
|
|
tEQ: 5,
|
|
tLT: 5,
|
|
tLTE: 5,
|
|
tGT: 5,
|
|
tGTE: 5,
|
|
tNE: 5,
|
|
tFlatten: 9,
|
|
tStar: 20,
|
|
tFilter: 21,
|
|
tDot: 40,
|
|
tNot: 45,
|
|
tLbrace: 50,
|
|
tLbracket: 55,
|
|
tLparen: 60,
|
|
}
|
|
|
|
// Parser holds state about the current expression being parsed.
|
|
type Parser struct {
|
|
expression string
|
|
tokens []token
|
|
index int
|
|
}
|
|
|
|
// NewParser creates a new JMESPath parser.
|
|
func NewParser() *Parser {
|
|
p := Parser{}
|
|
return &p
|
|
}
|
|
|
|
// Parse will compile a JMESPath expression.
|
|
func (p *Parser) Parse(expression string) (ASTNode, error) {
|
|
lexer := NewLexer()
|
|
p.expression = expression
|
|
p.index = 0
|
|
tokens, err := lexer.tokenize(expression)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
p.tokens = tokens
|
|
parsed, err := p.parseExpression(0)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
if p.current() != tEOF {
|
|
return ASTNode{}, p.syntaxError(fmt.Sprintf(
|
|
"Unexpected token at the end of the expresssion: %s", p.current()))
|
|
}
|
|
return parsed, nil
|
|
}
|
|
|
|
func (p *Parser) parseExpression(bindingPower int) (ASTNode, error) {
|
|
var err error
|
|
leftToken := p.lookaheadToken(0)
|
|
p.advance()
|
|
leftNode, err := p.nud(leftToken)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
currentToken := p.current()
|
|
for bindingPower < bindingPowers[currentToken] {
|
|
p.advance()
|
|
leftNode, err = p.led(currentToken, leftNode)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
currentToken = p.current()
|
|
}
|
|
return leftNode, nil
|
|
}
|
|
|
|
func (p *Parser) parseIndexExpression() (ASTNode, error) {
|
|
if p.lookahead(0) == tColon || p.lookahead(1) == tColon {
|
|
return p.parseSliceExpression()
|
|
}
|
|
indexStr := p.lookaheadToken(0).value
|
|
parsedInt, err := strconv.Atoi(indexStr)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
indexNode := ASTNode{nodeType: ASTIndex, value: parsedInt}
|
|
p.advance()
|
|
if err := p.match(tRbracket); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return indexNode, nil
|
|
}
|
|
|
|
func (p *Parser) parseSliceExpression() (ASTNode, error) {
|
|
parts := []*int{nil, nil, nil}
|
|
index := 0
|
|
current := p.current()
|
|
for current != tRbracket && index < 3 {
|
|
if current == tColon {
|
|
index++
|
|
p.advance()
|
|
} else if current == tNumber {
|
|
parsedInt, err := strconv.Atoi(p.lookaheadToken(0).value)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
parts[index] = &parsedInt
|
|
p.advance()
|
|
} else {
|
|
return ASTNode{}, p.syntaxError(
|
|
"Expected tColon or tNumber" + ", received: " + p.current().String())
|
|
}
|
|
current = p.current()
|
|
}
|
|
if err := p.match(tRbracket); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTSlice,
|
|
value: parts,
|
|
}, nil
|
|
}
|
|
|
|
func (p *Parser) match(tokenType tokType) error {
|
|
if p.current() == tokenType {
|
|
p.advance()
|
|
return nil
|
|
}
|
|
return p.syntaxError("Expected " + tokenType.String() + ", received: " + p.current().String())
|
|
}
|
|
|
|
func (p *Parser) led(tokenType tokType, node ASTNode) (ASTNode, error) {
|
|
switch tokenType {
|
|
case tDot:
|
|
if p.current() != tStar {
|
|
right, err := p.parseDotRHS(bindingPowers[tDot])
|
|
return ASTNode{
|
|
nodeType: ASTSubexpression,
|
|
children: []ASTNode{node, right},
|
|
}, err
|
|
}
|
|
p.advance()
|
|
right, err := p.parseProjectionRHS(bindingPowers[tDot])
|
|
return ASTNode{
|
|
nodeType: ASTValueProjection,
|
|
children: []ASTNode{node, right},
|
|
}, err
|
|
case tPipe:
|
|
right, err := p.parseExpression(bindingPowers[tPipe])
|
|
return ASTNode{nodeType: ASTPipe, children: []ASTNode{node, right}}, err
|
|
case tOr:
|
|
right, err := p.parseExpression(bindingPowers[tOr])
|
|
return ASTNode{nodeType: ASTOrExpression, children: []ASTNode{node, right}}, err
|
|
case tAnd:
|
|
right, err := p.parseExpression(bindingPowers[tAnd])
|
|
return ASTNode{nodeType: ASTAndExpression, children: []ASTNode{node, right}}, err
|
|
case tLparen:
|
|
name := node.value
|
|
var args []ASTNode
|
|
for p.current() != tRparen {
|
|
expression, err := p.parseExpression(0)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
if p.current() == tComma {
|
|
if err := p.match(tComma); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
}
|
|
args = append(args, expression)
|
|
}
|
|
if err := p.match(tRparen); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTFunctionExpression,
|
|
value: name,
|
|
children: args,
|
|
}, nil
|
|
case tFilter:
|
|
return p.parseFilter(node)
|
|
case tFlatten:
|
|
left := ASTNode{nodeType: ASTFlatten, children: []ASTNode{node}}
|
|
right, err := p.parseProjectionRHS(bindingPowers[tFlatten])
|
|
return ASTNode{
|
|
nodeType: ASTProjection,
|
|
children: []ASTNode{left, right},
|
|
}, err
|
|
case tEQ, tNE, tGT, tGTE, tLT, tLTE:
|
|
right, err := p.parseExpression(bindingPowers[tokenType])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTComparator,
|
|
value: tokenType,
|
|
children: []ASTNode{node, right},
|
|
}, nil
|
|
case tLbracket:
|
|
tokenType := p.current()
|
|
var right ASTNode
|
|
var err error
|
|
if tokenType == tNumber || tokenType == tColon {
|
|
right, err = p.parseIndexExpression()
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return p.projectIfSlice(node, right)
|
|
}
|
|
// Otherwise this is a projection.
|
|
if err := p.match(tStar); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
if err := p.match(tRbracket); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
right, err = p.parseProjectionRHS(bindingPowers[tStar])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTProjection,
|
|
children: []ASTNode{node, right},
|
|
}, nil
|
|
}
|
|
return ASTNode{}, p.syntaxError("Unexpected token: " + tokenType.String())
|
|
}
|
|
|
|
func (p *Parser) nud(token token) (ASTNode, error) {
|
|
switch token.tokenType {
|
|
case tJSONLiteral:
|
|
var parsed interface{}
|
|
err := json.Unmarshal([]byte(token.value), &parsed)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{nodeType: ASTLiteral, value: parsed}, nil
|
|
case tStringLiteral:
|
|
return ASTNode{nodeType: ASTLiteral, value: token.value}, nil
|
|
case tUnquotedIdentifier:
|
|
return ASTNode{
|
|
nodeType: ASTField,
|
|
value: token.value,
|
|
}, nil
|
|
case tQuotedIdentifier:
|
|
node := ASTNode{nodeType: ASTField, value: token.value}
|
|
if p.current() == tLparen {
|
|
return ASTNode{}, p.syntaxErrorToken("Can't have quoted identifier as function name.", token)
|
|
}
|
|
return node, nil
|
|
case tStar:
|
|
left := ASTNode{nodeType: ASTIdentity}
|
|
var right ASTNode
|
|
var err error
|
|
if p.current() == tRbracket {
|
|
right = ASTNode{nodeType: ASTIdentity}
|
|
} else {
|
|
right, err = p.parseProjectionRHS(bindingPowers[tStar])
|
|
}
|
|
return ASTNode{nodeType: ASTValueProjection, children: []ASTNode{left, right}}, err
|
|
case tFilter:
|
|
return p.parseFilter(ASTNode{nodeType: ASTIdentity})
|
|
case tLbrace:
|
|
return p.parseMultiSelectHash()
|
|
case tFlatten:
|
|
left := ASTNode{
|
|
nodeType: ASTFlatten,
|
|
children: []ASTNode{{nodeType: ASTIdentity}},
|
|
}
|
|
right, err := p.parseProjectionRHS(bindingPowers[tFlatten])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{nodeType: ASTProjection, children: []ASTNode{left, right}}, nil
|
|
case tLbracket:
|
|
tokenType := p.current()
|
|
//var right ASTNode
|
|
if tokenType == tNumber || tokenType == tColon {
|
|
right, err := p.parseIndexExpression()
|
|
if err != nil {
|
|
return ASTNode{}, nil
|
|
}
|
|
return p.projectIfSlice(ASTNode{nodeType: ASTIdentity}, right)
|
|
} else if tokenType == tStar && p.lookahead(1) == tRbracket {
|
|
p.advance()
|
|
p.advance()
|
|
right, err := p.parseProjectionRHS(bindingPowers[tStar])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTProjection,
|
|
children: []ASTNode{{nodeType: ASTIdentity}, right},
|
|
}, nil
|
|
} else {
|
|
return p.parseMultiSelectList()
|
|
}
|
|
case tCurrent:
|
|
return ASTNode{nodeType: ASTCurrentNode}, nil
|
|
case tExpref:
|
|
expression, err := p.parseExpression(bindingPowers[tExpref])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{nodeType: ASTExpRef, children: []ASTNode{expression}}, nil
|
|
case tNot:
|
|
expression, err := p.parseExpression(bindingPowers[tNot])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{nodeType: ASTNotExpression, children: []ASTNode{expression}}, nil
|
|
case tLparen:
|
|
expression, err := p.parseExpression(0)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
if err := p.match(tRparen); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return expression, nil
|
|
case tEOF:
|
|
return ASTNode{}, p.syntaxErrorToken("Incomplete expression", token)
|
|
}
|
|
|
|
return ASTNode{}, p.syntaxErrorToken("Invalid token: "+token.tokenType.String(), token)
|
|
}
|
|
|
|
func (p *Parser) parseMultiSelectList() (ASTNode, error) {
|
|
var expressions []ASTNode
|
|
for {
|
|
expression, err := p.parseExpression(0)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
expressions = append(expressions, expression)
|
|
if p.current() == tRbracket {
|
|
break
|
|
}
|
|
err = p.match(tComma)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
}
|
|
err := p.match(tRbracket)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTMultiSelectList,
|
|
children: expressions,
|
|
}, nil
|
|
}
|
|
|
|
func (p *Parser) parseMultiSelectHash() (ASTNode, error) {
|
|
var children []ASTNode
|
|
for {
|
|
keyToken := p.lookaheadToken(0)
|
|
if err := p.match(tUnquotedIdentifier); err != nil {
|
|
if err := p.match(tQuotedIdentifier); err != nil {
|
|
return ASTNode{}, p.syntaxError("Expected tQuotedIdentifier or tUnquotedIdentifier")
|
|
}
|
|
}
|
|
keyName := keyToken.value
|
|
err := p.match(tColon)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
value, err := p.parseExpression(0)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
node := ASTNode{
|
|
nodeType: ASTKeyValPair,
|
|
value: keyName,
|
|
children: []ASTNode{value},
|
|
}
|
|
children = append(children, node)
|
|
if p.current() == tComma {
|
|
err := p.match(tComma)
|
|
if err != nil {
|
|
return ASTNode{}, nil
|
|
}
|
|
} else if p.current() == tRbrace {
|
|
err := p.match(tRbrace)
|
|
if err != nil {
|
|
return ASTNode{}, nil
|
|
}
|
|
break
|
|
}
|
|
}
|
|
return ASTNode{
|
|
nodeType: ASTMultiSelectHash,
|
|
children: children,
|
|
}, nil
|
|
}
|
|
|
|
func (p *Parser) projectIfSlice(left ASTNode, right ASTNode) (ASTNode, error) {
|
|
indexExpr := ASTNode{
|
|
nodeType: ASTIndexExpression,
|
|
children: []ASTNode{left, right},
|
|
}
|
|
if right.nodeType == ASTSlice {
|
|
right, err := p.parseProjectionRHS(bindingPowers[tStar])
|
|
return ASTNode{
|
|
nodeType: ASTProjection,
|
|
children: []ASTNode{indexExpr, right},
|
|
}, err
|
|
}
|
|
return indexExpr, nil
|
|
}
|
|
func (p *Parser) parseFilter(node ASTNode) (ASTNode, error) {
|
|
var right, condition ASTNode
|
|
var err error
|
|
condition, err = p.parseExpression(0)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
if err := p.match(tRbracket); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
if p.current() == tFlatten {
|
|
right = ASTNode{nodeType: ASTIdentity}
|
|
} else {
|
|
right, err = p.parseProjectionRHS(bindingPowers[tFilter])
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
}
|
|
|
|
return ASTNode{
|
|
nodeType: ASTFilterProjection,
|
|
children: []ASTNode{node, right, condition},
|
|
}, nil
|
|
}
|
|
|
|
func (p *Parser) parseDotRHS(bindingPower int) (ASTNode, error) {
|
|
lookahead := p.current()
|
|
if tokensOneOf([]tokType{tQuotedIdentifier, tUnquotedIdentifier, tStar}, lookahead) {
|
|
return p.parseExpression(bindingPower)
|
|
} else if lookahead == tLbracket {
|
|
if err := p.match(tLbracket); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return p.parseMultiSelectList()
|
|
} else if lookahead == tLbrace {
|
|
if err := p.match(tLbrace); err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return p.parseMultiSelectHash()
|
|
}
|
|
return ASTNode{}, p.syntaxError("Expected identifier, lbracket, or lbrace")
|
|
}
|
|
|
|
func (p *Parser) parseProjectionRHS(bindingPower int) (ASTNode, error) {
|
|
current := p.current()
|
|
if bindingPowers[current] < 10 {
|
|
return ASTNode{nodeType: ASTIdentity}, nil
|
|
} else if current == tLbracket {
|
|
return p.parseExpression(bindingPower)
|
|
} else if current == tFilter {
|
|
return p.parseExpression(bindingPower)
|
|
} else if current == tDot {
|
|
err := p.match(tDot)
|
|
if err != nil {
|
|
return ASTNode{}, err
|
|
}
|
|
return p.parseDotRHS(bindingPower)
|
|
} else {
|
|
return ASTNode{}, p.syntaxError("Error")
|
|
}
|
|
}
|
|
|
|
func (p *Parser) lookahead(number int) tokType {
|
|
return p.lookaheadToken(number).tokenType
|
|
}
|
|
|
|
func (p *Parser) current() tokType {
|
|
return p.lookahead(0)
|
|
}
|
|
|
|
func (p *Parser) lookaheadToken(number int) token {
|
|
return p.tokens[p.index+number]
|
|
}
|
|
|
|
func (p *Parser) advance() {
|
|
p.index++
|
|
}
|
|
|
|
func tokensOneOf(elements []tokType, token tokType) bool {
|
|
for _, elem := range elements {
|
|
if elem == token {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (p *Parser) syntaxError(msg string) SyntaxError {
|
|
return SyntaxError{
|
|
msg: msg,
|
|
Expression: p.expression,
|
|
Offset: p.lookaheadToken(0).position,
|
|
}
|
|
}
|
|
|
|
// Create a SyntaxError based on the provided token.
|
|
// This differs from syntaxError() which creates a SyntaxError
|
|
// based on the current lookahead token.
|
|
func (p *Parser) syntaxErrorToken(msg string, t token) SyntaxError {
|
|
return SyntaxError{
|
|
msg: msg,
|
|
Expression: p.expression,
|
|
Offset: t.position,
|
|
}
|
|
}
|