Update dependencies (#1784)

vendor/github.com/graph-gophers/graphql-go/internal/common/lexer.go

@@ -0,0 +1,229 @@
+package common
+
+import (
+	"bytes"
+	"fmt"
+	"strconv"
+	"strings"
+	"text/scanner"
+
+	"github.com/graph-gophers/graphql-go/errors"
+	"github.com/graph-gophers/graphql-go/types"
+)
+
+type syntaxError string
+
+type Lexer struct {
+	sc                    *scanner.Scanner
+	next                  rune
+	comment               bytes.Buffer
+	useStringDescriptions bool
+}
+
+type Ident struct {
+	Name string
+	Loc  errors.Location
+}
+
+func NewLexer(s string, useStringDescriptions bool) *Lexer {
+	sc := &scanner.Scanner{
+		Mode: scanner.ScanIdents | scanner.ScanInts | scanner.ScanFloats | scanner.ScanStrings,
+	}
+	sc.Init(strings.NewReader(s))
+
+	l := Lexer{sc: sc, useStringDescriptions: useStringDescriptions}
+	l.sc.Error = l.CatchScannerError
+
+	return &l
+}
+
+func (l *Lexer) CatchSyntaxError(f func()) (errRes *errors.QueryError) {
+	defer func() {
+		if err := recover(); err != nil {
+			if err, ok := err.(syntaxError); ok {
+				errRes = errors.Errorf("syntax error: %s", err)
+				errRes.Locations = []errors.Location{l.Location()}
+				return
+			}
+			panic(err)
+		}
+	}()
+
+	f()
+	return
+}
+
+func (l *Lexer) Peek() rune {
+	return l.next
+}
+
+// ConsumeWhitespace consumes whitespace and tokens equivalent to whitespace (e.g. commas and comments).
+//
+// Consumed comment characters will build the description for the next type or field encountered.
+// The description is available from `DescComment()`, and will be reset every time `ConsumeWhitespace()` is
+// executed unless l.useStringDescriptions is set.
+func (l *Lexer) ConsumeWhitespace() {
+	l.comment.Reset()
+	for {
+		l.next = l.sc.Scan()
+
+		if l.next == ',' {
+			// Similar to white space and line terminators, commas (',') are used to improve the
+			// legibility of source text and separate lexical tokens but are otherwise syntactically and
+			// semantically insignificant within GraphQL documents.
+			//
+			// http://facebook.github.io/graphql/draft/#sec-Insignificant-Commas
+			continue
+		}
+
+		if l.next == '#' {
+			// GraphQL source documents may contain single-line comments, starting with the '#' marker.
+			//
+			// A comment can contain any Unicode code point except `LineTerminator` so a comment always
+			// consists of all code points starting with the '#' character up to but not including the
+			// line terminator.
+			l.consumeComment()
+			continue
+		}
+
+		break
+	}
+}
+
+// consumeDescription optionally consumes a description based on the June 2018 graphql spec if any are present.
+//
+// Single quote strings are also single line. Triple quote strings can be multi-line. Triple quote strings
+// whitespace trimmed on both ends.
+// If a description is found, consume any following comments as well
+//
+// http://facebook.github.io/graphql/June2018/#sec-Descriptions
+func (l *Lexer) consumeDescription() string {
+	// If the next token is not a string, we don't consume it
+	if l.next != scanner.String {
+		return ""
+	}
+	// Triple quote string is an empty "string" followed by an open quote due to the way the parser treats strings as one token
+	var desc string
+	if l.sc.Peek() == '"' {
+		desc = l.consumeTripleQuoteComment()
+	} else {
+		desc = l.consumeStringComment()
+	}
+	l.ConsumeWhitespace()
+	return desc
+}
+
+func (l *Lexer) ConsumeIdent() string {
+	name := l.sc.TokenText()
+	l.ConsumeToken(scanner.Ident)
+	return name
+}
+
+func (l *Lexer) ConsumeIdentWithLoc() types.Ident {
+	loc := l.Location()
+	name := l.sc.TokenText()
+	l.ConsumeToken(scanner.Ident)
+	return types.Ident{Name: name, Loc: loc}
+}
+
+func (l *Lexer) ConsumeKeyword(keyword string) {
+	if l.next != scanner.Ident || l.sc.TokenText() != keyword {
+		l.SyntaxError(fmt.Sprintf("unexpected %q, expecting %q", l.sc.TokenText(), keyword))
+	}
+	l.ConsumeWhitespace()
+}
+
+func (l *Lexer) ConsumeLiteral() *types.PrimitiveValue {
+	lit := &types.PrimitiveValue{Type: l.next, Text: l.sc.TokenText()}
+	l.ConsumeWhitespace()
+	return lit
+}
+
+func (l *Lexer) ConsumeToken(expected rune) {
+	if l.next != expected {
+		l.SyntaxError(fmt.Sprintf("unexpected %q, expecting %s", l.sc.TokenText(), scanner.TokenString(expected)))
+	}
+	l.ConsumeWhitespace()
+}
+
+func (l *Lexer) DescComment() string {
+	comment := l.comment.String()
+	desc := l.consumeDescription()
+	if l.useStringDescriptions {
+		return desc
+	}
+	return comment
+}
+
+func (l *Lexer) SyntaxError(message string) {
+	panic(syntaxError(message))
+}
+
+func (l *Lexer) Location() errors.Location {
+	return errors.Location{
+		Line:   l.sc.Line,
+		Column: l.sc.Column,
+	}
+}
+
+func (l *Lexer) consumeTripleQuoteComment() string {
+	l.next = l.sc.Next()
+	if l.next != '"' {
+		panic("consumeTripleQuoteComment used in wrong context: no third quote?")
+	}
+
+	var buf bytes.Buffer
+	var numQuotes int
+	for {
+		l.next = l.sc.Next()
+		if l.next == '"' {
+			numQuotes++
+		} else {
+			numQuotes = 0
+		}
+		buf.WriteRune(l.next)
+		if numQuotes == 3 || l.next == scanner.EOF {
+			break
+		}
+	}
+	val := buf.String()
+	val = val[:len(val)-numQuotes]
+	return blockString(val)
+}
+
+func (l *Lexer) consumeStringComment() string {
+	val, err := strconv.Unquote(l.sc.TokenText())
+	if err != nil {
+		panic(err)
+	}
+	return val
+}
+
+// consumeComment consumes all characters from `#` to the first encountered line terminator.
+// The characters are appended to `l.comment`.
+func (l *Lexer) consumeComment() {
+	if l.next != '#' {
+		panic("consumeComment used in wrong context")
+	}
+
+	// TODO: count and trim whitespace so we can dedent any following lines.
+	if l.sc.Peek() == ' ' {
+		l.sc.Next()
+	}
+
+	if l.comment.Len() > 0 {
+		l.comment.WriteRune('\n')
+	}
+
+	for {
+		next := l.sc.Next()
+		if next == '\r' || next == '\n' || next == scanner.EOF {
+			break
+		}
+		l.comment.WriteRune(next)
+	}
+}
+
+func (l *Lexer) CatchScannerError(s *scanner.Scanner, msg string) {
+	l.SyntaxError(msg)
+}