765 lines
13 KiB
Go
765 lines
13 KiB
Go
package qcode
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import (
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"errors"
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"fmt"
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"hash/maphash"
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"sync"
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"unsafe"
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)
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var (
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errEOT = errors.New("end of tokens")
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)
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type parserType int32
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const (
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maxFields = 1200
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maxArgs = 25
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)
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const (
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parserError parserType = iota
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parserEOF
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opQuery
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opMutate
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opSub
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NodeStr
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NodeInt
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NodeFloat
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NodeBool
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NodeObj
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NodeList
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NodeVar
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)
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type Operation struct {
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Type parserType
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Name string
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Args []Arg
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argsA [10]Arg
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Fields []Field
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fieldsA [10]Field
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}
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var zeroOperation = Operation{}
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func (o *Operation) Reset() {
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*o = zeroOperation
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}
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type Fragment struct {
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Name string
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On string
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Fields []Field
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fieldsA [10]Field
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}
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var zeroFragment = Fragment{}
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func (f *Fragment) Reset() {
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*f = zeroFragment
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}
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type Field struct {
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ID int32
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ParentID int32
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Name string
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Alias string
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Args []Arg
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argsA [5]Arg
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Children []int32
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childrenA [5]int32
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Union bool
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}
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type Arg struct {
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Name string
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Val *Node
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df bool
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}
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type Node struct {
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Type parserType
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Name string
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Val string
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Parent *Node
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Children []*Node
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exp *Exp
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}
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var zeroNode = Node{}
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func (n *Node) Reset() {
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*n = zeroNode
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}
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type Parser struct {
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frags map[uint64]*Fragment
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h maphash.Hash
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input []byte // the string being scanned
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pos int
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items []item
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err error
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}
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var nodePool = sync.Pool{
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New: func() interface{} { return new(Node) },
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}
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var opPool = sync.Pool{
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New: func() interface{} { return new(Operation) },
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}
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var fragPool = sync.Pool{
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New: func() interface{} { return new(Fragment) },
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}
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var lexPool = sync.Pool{
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New: func() interface{} { return new(lexer) },
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}
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func Parse(gql []byte) (*Operation, error) {
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var err error
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if len(gql) == 0 {
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return nil, errors.New("blank query")
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}
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l := lexPool.Get().(*lexer)
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l.Reset()
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defer lexPool.Put(l)
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if err = lex(l, gql); err != nil {
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return nil, err
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}
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p := &Parser{
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input: l.input,
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pos: -1,
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items: l.items,
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}
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op := opPool.Get().(*Operation)
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op.Reset()
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op.Fields = op.fieldsA[:0]
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s := -1
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qf := false
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for {
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if p.peek(itemEOF) {
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p.ignore()
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break
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}
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if p.peek(itemFragment) {
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p.ignore()
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if f, err := p.parseFragment(); err != nil {
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fragPool.Put(f)
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return nil, err
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}
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} else {
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if !qf && p.peek(itemQuery, itemMutation, itemSub, itemObjOpen) {
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s = p.pos
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qf = true
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}
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p.ignore()
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}
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}
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p.reset(s)
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if err := p.parseOp(op); err != nil {
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return nil, err
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}
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for _, v := range p.frags {
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fragPool.Put(v)
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}
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return op, nil
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}
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func (p *Parser) parseFragment() (*Fragment, error) {
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var err error
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frag := fragPool.Get().(*Fragment)
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frag.Reset()
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frag.Fields = frag.fieldsA[:0]
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if p.peek(itemName) {
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frag.Name = p.val(p.next())
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} else {
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return frag, errors.New("fragment: missing name")
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}
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if p.peek(itemOn) {
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p.ignore()
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} else {
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return frag, errors.New("fragment: missing 'on' keyword")
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}
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if p.peek(itemName) {
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frag.On = p.vall(p.next())
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} else {
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return frag, errors.New("fragment: missing table name after 'on' keyword")
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}
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if p.peek(itemObjOpen) {
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p.ignore()
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} else {
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return frag, fmt.Errorf("fragment: expecting a '{', got: %s", p.next())
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}
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frag.Fields, err = p.parseFields(frag.Fields)
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if err != nil {
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return frag, fmt.Errorf("fragment: %v", err)
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}
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if p.frags == nil {
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p.frags = make(map[uint64]*Fragment)
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}
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_, _ = p.h.WriteString(frag.Name)
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k := p.h.Sum64()
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p.h.Reset()
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p.frags[k] = frag
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return frag, nil
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}
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func (p *Parser) parseOp(op *Operation) error {
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var err error
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var typeSet bool
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if p.peek(itemQuery, itemMutation, itemSub) {
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err = p.parseOpTypeAndArgs(op)
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if err != nil {
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return fmt.Errorf("%s: %v", op.Type, err)
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}
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typeSet = true
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}
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if p.peek(itemObjOpen) {
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p.ignore()
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if !typeSet {
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op.Type = opQuery
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}
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for {
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if p.peek(itemEOF, itemFragment) {
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p.ignore()
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break
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}
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op.Fields, err = p.parseFields(op.Fields)
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if err != nil {
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return fmt.Errorf("%s: %v", op.Type, err)
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}
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}
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} else {
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return fmt.Errorf("expecting a query, mutation or subscription, got: %s", p.next())
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}
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return nil
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}
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func (p *Parser) parseOpTypeAndArgs(op *Operation) error {
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item := p.next()
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switch item._type {
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case itemQuery:
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op.Type = opQuery
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case itemMutation:
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op.Type = opMutate
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case itemSub:
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op.Type = opSub
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}
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op.Args = op.argsA[:0]
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var err error
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if p.peek(itemName) {
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op.Name = p.val(p.next())
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}
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if p.peek(itemArgsOpen) {
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p.ignore()
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op.Args, err = p.parseOpParams(op.Args)
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if err != nil {
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return err
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}
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}
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return nil
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}
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func ParseArgValue(argVal string) (*Node, error) {
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l := lexPool.Get().(*lexer)
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l.Reset()
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if err := lex(l, []byte(argVal)); err != nil {
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return nil, err
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}
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p := &Parser{
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input: l.input,
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pos: -1,
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items: l.items,
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}
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op, err := p.parseValue()
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lexPool.Put(l)
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return op, err
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}
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func (p *Parser) parseFields(fields []Field) ([]Field, error) {
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var err error
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st := NewStack()
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if !p.peek(itemName, itemSpread) {
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return nil, fmt.Errorf("unexpected token: %s", p.peekNext())
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}
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for {
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if p.peek(itemEOF) {
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p.ignore()
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return nil, errors.New("invalid query")
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}
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if p.peek(itemObjClose) {
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p.ignore()
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if st.Len() != 0 {
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st.Pop()
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continue
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} else {
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break
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}
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}
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if len(fields) >= maxFields {
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return nil, fmt.Errorf("too many fields (max %d)", maxFields)
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}
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isFrag := false
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if p.peek(itemSpread) {
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p.ignore()
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isFrag = true
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}
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if isFrag {
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fields, err = p.parseFragmentFields(st, fields)
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} else {
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fields, err = p.parseNormalFields(st, fields)
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}
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if err != nil {
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return nil, err
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}
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}
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return fields, nil
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}
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func (p *Parser) parseNormalFields(st *Stack, fields []Field) ([]Field, error) {
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if !p.peek(itemName) {
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return nil, fmt.Errorf("expecting an alias or field name, got: %s", p.next())
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}
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fields = append(fields, Field{ID: int32(len(fields))})
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f := &fields[(len(fields) - 1)]
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f.Args = f.argsA[:0]
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f.Children = f.childrenA[:0]
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// Parse the field
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if err := p.parseField(f); err != nil {
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return nil, err
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}
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if st.Len() == 0 {
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f.ParentID = -1
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} else {
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pid := st.Peek()
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f.ParentID = pid
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fields[pid].Children = append(fields[pid].Children, f.ID)
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}
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// The first opening curley brackets after this
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// comes the columns or child fields
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if p.peek(itemObjOpen) {
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p.ignore()
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st.Push(f.ID)
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}
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return fields, nil
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}
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func (p *Parser) parseFragmentFields(st *Stack, fields []Field) ([]Field, error) {
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var err error
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pid := st.Peek()
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if p.peek(itemOn) {
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p.ignore()
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fields[pid].Union = true
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if fields, err = p.parseNormalFields(st, fields); err != nil {
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return nil, err
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}
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// If parent is a union selector than copy over args from the parent
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// to the first child which is the root selector for each union type.
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for i := pid + 1; i < int32(len(fields)); i++ {
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f := &fields[i]
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if f.ParentID == pid {
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f.Args = fields[pid].Args
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}
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}
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} else {
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if !p.peek(itemName) {
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return nil, fmt.Errorf("expecting a fragment name, got: %s", p.next())
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}
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name := p.val(p.next())
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_, _ = p.h.WriteString(name)
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id := p.h.Sum64()
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p.h.Reset()
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fr, ok := p.frags[id]
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if !ok {
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return nil, fmt.Errorf("no fragment named '%s' defined", name)
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}
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ff := fr.Fields
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parent := &fields[pid]
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n := int32(len(fields))
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fields = append(fields, ff...)
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for i := 0; i < len(ff); i++ {
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k := (n + int32(i))
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f := &fields[k]
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f.ID = int32(k)
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// If this is the top-level point the parent to the parent of the
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// previous field.
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if f.ParentID == -1 {
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f.ParentID = pid
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if f.ParentID != -1 {
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parent.Children = append(parent.Children, f.ID)
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}
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// Update all the other parents id's by our new place in this new array
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} else {
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f.ParentID += n
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}
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// Copy over children since fields append is not a deep copy
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f.Children = make([]int32, len(f.Children))
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copy(f.Children, ff[i].Children)
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// Copy over args since args append is not a deep copy
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f.Args = make([]Arg, len(f.Args))
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copy(f.Args, ff[i].Args)
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// Update all the children which is needed.
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for j := range f.Children {
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f.Children[j] += n
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}
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}
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}
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return fields, nil
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}
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func (p *Parser) parseField(f *Field) error {
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var err error
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v := p.next()
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if p.peek(itemColon) {
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p.ignore()
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if p.peek(itemName) {
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f.Alias = p.val(v)
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f.Name = p.vall(p.next())
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} else {
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return errors.New("expecting an aliased field name")
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}
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} else {
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f.Name = p.vall(v)
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}
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if p.peek(itemArgsOpen) {
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p.ignore()
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if f.Args, err = p.parseArgs(f.Args); err != nil {
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return err
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}
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}
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return nil
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}
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func (p *Parser) parseOpParams(args []Arg) ([]Arg, error) {
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for {
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if len(args) >= maxArgs {
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return nil, fmt.Errorf("too many args (max %d)", maxArgs)
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}
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if p.peek(itemEOF, itemArgsClose) {
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p.ignore()
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break
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}
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p.next()
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}
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return args, nil
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}
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func (p *Parser) parseArgs(args []Arg) ([]Arg, error) {
|
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var err error
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for {
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if len(args) >= maxArgs {
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return nil, fmt.Errorf("too many args (max %d)", maxArgs)
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}
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if p.peek(itemEOF, itemArgsClose) {
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p.ignore()
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break
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}
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if !p.peek(itemName) {
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return nil, errors.New("expecting an argument name")
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}
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args = append(args, Arg{Name: p.val(p.next())})
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arg := &args[(len(args) - 1)]
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|
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if !p.peek(itemColon) {
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return nil, errors.New("missing ':' after argument name")
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}
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p.ignore()
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arg.Val, err = p.parseValue()
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if err != nil {
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return nil, err
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}
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}
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return args, nil
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}
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func (p *Parser) parseList() (*Node, error) {
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nodes := []*Node{}
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parent := nodePool.Get().(*Node)
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parent.Reset()
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var ty parserType
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for {
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if p.peek(itemListClose) {
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p.ignore()
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break
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}
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node, err := p.parseValue()
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if err != nil {
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return nil, err
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}
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if ty == 0 {
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ty = node.Type
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} else if ty != node.Type {
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return nil, errors.New("All values in a list must be of the same type")
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}
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node.Parent = parent
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nodes = append(nodes, node)
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}
|
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if len(nodes) == 0 {
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return nil, errors.New("List cannot be empty")
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}
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parent.Type = NodeList
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parent.Children = nodes
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return parent, nil
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}
|
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|
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func (p *Parser) parseObj() (*Node, error) {
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nodes := []*Node{}
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parent := nodePool.Get().(*Node)
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parent.Reset()
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for {
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if p.peek(itemEOF, itemObjClose) {
|
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p.ignore()
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break
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}
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|
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if !p.peek(itemName) {
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return nil, errors.New("expecting an argument name")
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}
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nodeName := p.val(p.next())
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|
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if !p.peek(itemColon) {
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return nil, errors.New("missing ':' after Field argument name")
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}
|
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p.ignore()
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|
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node, err := p.parseValue()
|
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if err != nil {
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return nil, err
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}
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node.Name = nodeName
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node.Parent = parent
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nodes = append(nodes, node)
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}
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parent.Type = NodeObj
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parent.Children = nodes
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return parent, nil
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}
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|
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func (p *Parser) parseValue() (*Node, error) {
|
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if p.peek(itemListOpen) {
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p.ignore()
|
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return p.parseList()
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}
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|
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if p.peek(itemObjOpen) {
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p.ignore()
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return p.parseObj()
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}
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|
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item := p.next()
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node := nodePool.Get().(*Node)
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node.Reset()
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|
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switch item._type {
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case itemIntVal:
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node.Type = NodeInt
|
|
case itemFloatVal:
|
|
node.Type = NodeFloat
|
|
case itemStringVal:
|
|
node.Type = NodeStr
|
|
case itemBoolVal:
|
|
node.Type = NodeBool
|
|
case itemName:
|
|
node.Type = NodeStr
|
|
case itemVariable:
|
|
node.Type = NodeVar
|
|
default:
|
|
return nil, fmt.Errorf("expecting a number, string, object, list or variable as an argument value (not %s)", p.val(p.next()))
|
|
}
|
|
node.Val = p.val(item)
|
|
|
|
return node, nil
|
|
}
|
|
|
|
func (p *Parser) val(v item) string {
|
|
return b2s(p.input[v.pos:v.end])
|
|
}
|
|
|
|
func (p *Parser) vall(v item) string {
|
|
lowercase(p.input, v.pos, v.end)
|
|
return b2s(p.input[v.pos:v.end])
|
|
}
|
|
|
|
func (p *Parser) peek(types ...itemType) bool {
|
|
n := p.pos + 1
|
|
l := len(types)
|
|
// if p.items[n]._type == itemEOF {
|
|
// return false
|
|
// }
|
|
|
|
if n >= len(p.items) {
|
|
return types[0] == itemEOF
|
|
}
|
|
|
|
if l == 1 {
|
|
return p.items[n]._type == types[0]
|
|
}
|
|
|
|
for i := 0; i < l; i++ {
|
|
if p.items[n]._type == types[i] {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
func (p *Parser) next() item {
|
|
n := p.pos + 1
|
|
if n >= len(p.items) {
|
|
p.err = errEOT
|
|
return item{_type: itemEOF}
|
|
}
|
|
p.pos = n
|
|
return p.items[p.pos]
|
|
}
|
|
|
|
func (p *Parser) ignore() {
|
|
n := p.pos + 1
|
|
if n >= len(p.items) {
|
|
p.err = errEOT
|
|
return
|
|
}
|
|
p.pos = n
|
|
}
|
|
|
|
func (p *Parser) peekNext() string {
|
|
item := p.items[p.pos+1]
|
|
return b2s(p.input[item.pos:item.end])
|
|
}
|
|
|
|
func (p *Parser) reset(to int) {
|
|
p.pos = to
|
|
}
|
|
|
|
func b2s(b []byte) string {
|
|
return *(*string)(unsafe.Pointer(&b))
|
|
}
|
|
|
|
func (t parserType) String() string {
|
|
var v string
|
|
|
|
switch t {
|
|
case parserEOF:
|
|
v = "EOF"
|
|
case parserError:
|
|
v = "error"
|
|
case opQuery:
|
|
v = "query"
|
|
case opMutate:
|
|
v = "mutation"
|
|
case opSub:
|
|
v = "subscription"
|
|
case NodeStr:
|
|
v = "node-string"
|
|
case NodeInt:
|
|
v = "node-int"
|
|
case NodeFloat:
|
|
v = "node-float"
|
|
case NodeBool:
|
|
v = "node-bool"
|
|
case NodeVar:
|
|
v = "node-var"
|
|
case NodeObj:
|
|
v = "node-obj"
|
|
case NodeList:
|
|
v = "node-list"
|
|
}
|
|
return v
|
|
}
|
|
|
|
func FreeNode(n *Node) {
|
|
nodePool.Put(n)
|
|
}
|