vendor tsgo

tools/tsgo/internal/printer/textwriter.go

@@ -0,0 +1,227 @@
+package printer
+
+import (
+	"strings"
+	"unicode/utf8"
+
+	"github.com/microsoft/typescript-go/internal/ast"
+	"github.com/microsoft/typescript-go/internal/core"
+	"github.com/microsoft/typescript-go/internal/stringutil"
+)
+
+var _ EmitTextWriter = &textWriter{}
+
+type textWriter struct {
+	newLine                 string
+	indentSize              int
+	builder                 strings.Builder
+	lastWritten             string
+	indent                  int
+	lineStart               bool
+	lineCount               int
+	linePos                 int
+	hasTrailingCommentState bool
+}
+
+func (w *textWriter) Clear() {
+	*w = textWriter{newLine: w.newLine, indentSize: w.indentSize, lineStart: true}
+}
+
+func (w *textWriter) Grow(n int) {
+	w.builder.Grow(n)
+}
+
+func (w *textWriter) DecreaseIndent() {
+	w.indent--
+}
+
+// GetColumn returns the column position measured in UTF-16 code units
+// for source map compatibility.
+func (w *textWriter) GetColumn() core.UTF16Offset {
+	if w.lineStart {
+		return core.UTF16Offset(w.indent * w.indentSize)
+	}
+	// Count UTF-16 code units from the last line start.
+	// For ASCII-only output (the common case), this equals the byte count.
+	return core.UTF16Len(w.builder.String()[w.linePos:])
+}
+
+func (w *textWriter) GetIndent() int {
+	return w.indent
+}
+
+func (w *textWriter) GetLine() int {
+	return w.lineCount
+}
+
+func (w *textWriter) String() string {
+	return w.builder.String()
+}
+
+func (w *textWriter) GetTextPos() int {
+	return w.builder.Len()
+}
+
+func (w textWriter) HasTrailingComment() bool {
+	return w.hasTrailingCommentState
+}
+
+func (w *textWriter) HasTrailingWhitespace() bool {
+	if w.builder.Len() == 0 {
+		return false
+	}
+	ch, _ := utf8.DecodeLastRuneInString(w.lastWritten)
+	if ch == utf8.RuneError {
+		return false
+	}
+	return stringutil.IsWhiteSpaceLike(ch)
+}
+
+func (w *textWriter) IncreaseIndent() {
+	w.indent++
+}
+
+func (w *textWriter) IsAtStartOfLine() bool {
+	return w.lineStart
+}
+
+func (w *textWriter) RawWrite(s string) {
+	if s != "" {
+		w.builder.WriteString(s)
+		w.lastWritten = s
+		w.hasTrailingCommentState = false
+	}
+	w.updateLineCountAndPosFor(s)
+}
+
+func (w *textWriter) updateLineCountAndPosFor(s string) {
+	var count int
+	var lastLineStart core.TextPos
+
+	for lineStart := range core.ComputeECMALineStartsSeq(s) {
+		count++
+		lastLineStart = lineStart
+	}
+
+	if count > 1 {
+		w.lineCount += count - 1
+		curLen := w.builder.Len()
+		w.linePos = curLen - len(s) + int(lastLineStart)
+		w.lineStart = (w.linePos - curLen) == 0
+		return
+	}
+	w.lineStart = false
+}
+
+const defaultIndentSize = 4
+
+// GetDefaultIndentSize returns the default indent size (4 spaces) used when no specific indent size is configured.
+func GetDefaultIndentSize() int {
+	return defaultIndentSize
+}
+
+func getIndentString(indent int, indentSize int) string {
+	if indent == 0 {
+		return ""
+	}
+	// TODO: This is cached in tsc - should it be cached here?
+	return strings.Repeat(" ", indent*indentSize)
+}
+
+func (w *textWriter) writeText(s string) {
+	if s != "" {
+		if w.lineStart {
+			w.builder.WriteString(getIndentString(w.indent, w.indentSize))
+			w.lineStart = false
+		}
+		w.builder.WriteString(s)
+		w.lastWritten = s
+		w.updateLineCountAndPosFor(s)
+	}
+}
+
+func (w *textWriter) Write(s string) {
+	if s != "" {
+		w.hasTrailingCommentState = false
+	}
+	w.writeText(s)
+}
+
+func (w *textWriter) WriteComment(text string) {
+	if text != "" {
+		w.hasTrailingCommentState = true
+	}
+	w.writeText(text)
+}
+
+func (w *textWriter) WriteKeyword(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) writeLineRaw() {
+	w.builder.WriteString(w.newLine)
+	w.lastWritten = w.newLine
+	w.lineCount++
+	w.linePos = w.builder.Len()
+	w.lineStart = true
+	w.hasTrailingCommentState = false
+}
+
+func (w *textWriter) WriteLine() {
+	if !w.lineStart {
+		w.writeLineRaw()
+	}
+}
+
+func (w *textWriter) WriteLineForce(force bool) {
+	if !w.lineStart || force {
+		w.writeLineRaw()
+	}
+}
+
+func (w *textWriter) WriteLiteral(s string) {
+	w.Write(s)
+}
+
+func (w *textWriter) WriteOperator(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) WriteParameter(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) WriteProperty(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) WritePunctuation(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) WriteSpace(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) WriteStringLiteral(text string) {
+	w.Write(text)
+}
+
+func (w *textWriter) WriteSymbol(text string, symbol *ast.Symbol) {
+	w.Write(text)
+}
+
+func (w *textWriter) WriteTrailingSemicolon(text string) {
+	w.Write(text)
+}
+
+func NewTextWriter(newLine string, indentSize int) EmitTextWriter {
+	if indentSize <= 0 {
+		indentSize = 4
+	}
+	var w textWriter
+	w.newLine = newLine
+	w.indentSize = indentSize
+	w.Clear()
+	return &w
+}