distribution/vendor/github.com/jmespath/go-jmespath/interpreter.go
Derek McGowan a685e3fc98
Replace godep with vndr
Vndr has a simpler configuration and allows pointing to forked
packages. Additionally other docker projects are now using
vndr making vendoring in distribution more consistent.

Updates letsencrypt to use fork.
No longer uses sub-vendored packages.

Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
2016-11-23 15:07:06 -08:00

418 lines
10 KiB
Go

package jmespath
import (
"errors"
"reflect"
"unicode"
"unicode/utf8"
)
/* This is a tree based interpreter. It walks the AST and directly
interprets the AST to search through a JSON document.
*/
type treeInterpreter struct {
fCall *functionCaller
}
func newInterpreter() *treeInterpreter {
interpreter := treeInterpreter{}
interpreter.fCall = newFunctionCaller()
return &interpreter
}
type expRef struct {
ref ASTNode
}
// Execute takes an ASTNode and input data and interprets the AST directly.
// It will produce the result of applying the JMESPath expression associated
// with the ASTNode to the input data "value".
func (intr *treeInterpreter) Execute(node ASTNode, value interface{}) (interface{}, error) {
switch node.nodeType {
case ASTComparator:
left, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, err
}
right, err := intr.Execute(node.children[1], value)
if err != nil {
return nil, err
}
switch node.value {
case tEQ:
return objsEqual(left, right), nil
case tNE:
return !objsEqual(left, right), nil
}
leftNum, ok := left.(float64)
if !ok {
return nil, nil
}
rightNum, ok := right.(float64)
if !ok {
return nil, nil
}
switch node.value {
case tGT:
return leftNum > rightNum, nil
case tGTE:
return leftNum >= rightNum, nil
case tLT:
return leftNum < rightNum, nil
case tLTE:
return leftNum <= rightNum, nil
}
case ASTExpRef:
return expRef{ref: node.children[0]}, nil
case ASTFunctionExpression:
resolvedArgs := []interface{}{}
for _, arg := range node.children {
current, err := intr.Execute(arg, value)
if err != nil {
return nil, err
}
resolvedArgs = append(resolvedArgs, current)
}
return intr.fCall.CallFunction(node.value.(string), resolvedArgs, intr)
case ASTField:
if m, ok := value.(map[string]interface{}); ok {
key := node.value.(string)
return m[key], nil
}
return intr.fieldFromStruct(node.value.(string), value)
case ASTFilterProjection:
left, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, nil
}
sliceType, ok := left.([]interface{})
if !ok {
if isSliceType(left) {
return intr.filterProjectionWithReflection(node, left)
}
return nil, nil
}
compareNode := node.children[2]
collected := []interface{}{}
for _, element := range sliceType {
result, err := intr.Execute(compareNode, element)
if err != nil {
return nil, err
}
if !isFalse(result) {
current, err := intr.Execute(node.children[1], element)
if err != nil {
return nil, err
}
if current != nil {
collected = append(collected, current)
}
}
}
return collected, nil
case ASTFlatten:
left, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, nil
}
sliceType, ok := left.([]interface{})
if !ok {
// If we can't type convert to []interface{}, there's
// a chance this could still work via reflection if we're
// dealing with user provided types.
if isSliceType(left) {
return intr.flattenWithReflection(left)
}
return nil, nil
}
flattened := []interface{}{}
for _, element := range sliceType {
if elementSlice, ok := element.([]interface{}); ok {
flattened = append(flattened, elementSlice...)
} else if isSliceType(element) {
reflectFlat := []interface{}{}
v := reflect.ValueOf(element)
for i := 0; i < v.Len(); i++ {
reflectFlat = append(reflectFlat, v.Index(i).Interface())
}
flattened = append(flattened, reflectFlat...)
} else {
flattened = append(flattened, element)
}
}
return flattened, nil
case ASTIdentity, ASTCurrentNode:
return value, nil
case ASTIndex:
if sliceType, ok := value.([]interface{}); ok {
index := node.value.(int)
if index < 0 {
index += len(sliceType)
}
if index < len(sliceType) && index >= 0 {
return sliceType[index], nil
}
return nil, nil
}
// Otherwise try via reflection.
rv := reflect.ValueOf(value)
if rv.Kind() == reflect.Slice {
index := node.value.(int)
if index < 0 {
index += rv.Len()
}
if index < rv.Len() && index >= 0 {
v := rv.Index(index)
return v.Interface(), nil
}
}
return nil, nil
case ASTKeyValPair:
return intr.Execute(node.children[0], value)
case ASTLiteral:
return node.value, nil
case ASTMultiSelectHash:
if value == nil {
return nil, nil
}
collected := make(map[string]interface{})
for _, child := range node.children {
current, err := intr.Execute(child, value)
if err != nil {
return nil, err
}
key := child.value.(string)
collected[key] = current
}
return collected, nil
case ASTMultiSelectList:
if value == nil {
return nil, nil
}
collected := []interface{}{}
for _, child := range node.children {
current, err := intr.Execute(child, value)
if err != nil {
return nil, err
}
collected = append(collected, current)
}
return collected, nil
case ASTOrExpression:
matched, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, err
}
if isFalse(matched) {
matched, err = intr.Execute(node.children[1], value)
if err != nil {
return nil, err
}
}
return matched, nil
case ASTAndExpression:
matched, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, err
}
if isFalse(matched) {
return matched, nil
}
return intr.Execute(node.children[1], value)
case ASTNotExpression:
matched, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, err
}
if isFalse(matched) {
return true, nil
}
return false, nil
case ASTPipe:
result := value
var err error
for _, child := range node.children {
result, err = intr.Execute(child, result)
if err != nil {
return nil, err
}
}
return result, nil
case ASTProjection:
left, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, err
}
sliceType, ok := left.([]interface{})
if !ok {
if isSliceType(left) {
return intr.projectWithReflection(node, left)
}
return nil, nil
}
collected := []interface{}{}
var current interface{}
for _, element := range sliceType {
current, err = intr.Execute(node.children[1], element)
if err != nil {
return nil, err
}
if current != nil {
collected = append(collected, current)
}
}
return collected, nil
case ASTSubexpression, ASTIndexExpression:
left, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, err
}
return intr.Execute(node.children[1], left)
case ASTSlice:
sliceType, ok := value.([]interface{})
if !ok {
if isSliceType(value) {
return intr.sliceWithReflection(node, value)
}
return nil, nil
}
parts := node.value.([]*int)
sliceParams := make([]sliceParam, 3)
for i, part := range parts {
if part != nil {
sliceParams[i].Specified = true
sliceParams[i].N = *part
}
}
return slice(sliceType, sliceParams)
case ASTValueProjection:
left, err := intr.Execute(node.children[0], value)
if err != nil {
return nil, nil
}
mapType, ok := left.(map[string]interface{})
if !ok {
return nil, nil
}
values := make([]interface{}, len(mapType))
for _, value := range mapType {
values = append(values, value)
}
collected := []interface{}{}
for _, element := range values {
current, err := intr.Execute(node.children[1], element)
if err != nil {
return nil, err
}
if current != nil {
collected = append(collected, current)
}
}
return collected, nil
}
return nil, errors.New("Unknown AST node: " + node.nodeType.String())
}
func (intr *treeInterpreter) fieldFromStruct(key string, value interface{}) (interface{}, error) {
rv := reflect.ValueOf(value)
first, n := utf8.DecodeRuneInString(key)
fieldName := string(unicode.ToUpper(first)) + key[n:]
if rv.Kind() == reflect.Struct {
v := rv.FieldByName(fieldName)
if !v.IsValid() {
return nil, nil
}
return v.Interface(), nil
} else if rv.Kind() == reflect.Ptr {
// Handle multiple levels of indirection?
if rv.IsNil() {
return nil, nil
}
rv = rv.Elem()
v := rv.FieldByName(fieldName)
if !v.IsValid() {
return nil, nil
}
return v.Interface(), nil
}
return nil, nil
}
func (intr *treeInterpreter) flattenWithReflection(value interface{}) (interface{}, error) {
v := reflect.ValueOf(value)
flattened := []interface{}{}
for i := 0; i < v.Len(); i++ {
element := v.Index(i).Interface()
if reflect.TypeOf(element).Kind() == reflect.Slice {
// Then insert the contents of the element
// slice into the flattened slice,
// i.e flattened = append(flattened, mySlice...)
elementV := reflect.ValueOf(element)
for j := 0; j < elementV.Len(); j++ {
flattened = append(
flattened, elementV.Index(j).Interface())
}
} else {
flattened = append(flattened, element)
}
}
return flattened, nil
}
func (intr *treeInterpreter) sliceWithReflection(node ASTNode, value interface{}) (interface{}, error) {
v := reflect.ValueOf(value)
parts := node.value.([]*int)
sliceParams := make([]sliceParam, 3)
for i, part := range parts {
if part != nil {
sliceParams[i].Specified = true
sliceParams[i].N = *part
}
}
final := []interface{}{}
for i := 0; i < v.Len(); i++ {
element := v.Index(i).Interface()
final = append(final, element)
}
return slice(final, sliceParams)
}
func (intr *treeInterpreter) filterProjectionWithReflection(node ASTNode, value interface{}) (interface{}, error) {
compareNode := node.children[2]
collected := []interface{}{}
v := reflect.ValueOf(value)
for i := 0; i < v.Len(); i++ {
element := v.Index(i).Interface()
result, err := intr.Execute(compareNode, element)
if err != nil {
return nil, err
}
if !isFalse(result) {
current, err := intr.Execute(node.children[1], element)
if err != nil {
return nil, err
}
if current != nil {
collected = append(collected, current)
}
}
}
return collected, nil
}
func (intr *treeInterpreter) projectWithReflection(node ASTNode, value interface{}) (interface{}, error) {
collected := []interface{}{}
v := reflect.ValueOf(value)
for i := 0; i < v.Len(); i++ {
element := v.Index(i).Interface()
result, err := intr.Execute(node.children[1], element)
if err != nil {
return nil, err
}
if result != nil {
collected = append(collected, result)
}
}
return collected, nil
}