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