parser/gotest: Create interface for reading lines with metadata

Author: jstemmer

parser/gotest/gotest.go

@@ -133,10 +133,10 @@ func (p *Parser) Parse(r io.Reader) (gtr.Report, error) {
 	return p.parse(reader.NewLimitedLineReader(r, maxLineSize))
 }
 
-func (p *Parser) parse(r *reader.LimitedLineReader) (gtr.Report, error) {
+func (p *Parser) parse(r reader.LineReader) (gtr.Report, error) {
 	p.events = nil
 	for {
-		line, err := r.ReadLine()
+		line, _, err := r.ReadLine()
 		if err == io.EOF {
 			break
 		} else if err != nil {

parser/gotest/internal/reader/reader.go

@@ -6,6 +6,16 @@ import (
 	"io"
 )
 
+// LineReader is an interface to read lines with optional Metadata.
+type LineReader interface {
+	ReadLine() (string, *Metadata, error)
+}
+
+// Metadata contains metadata that belongs to a line.
+type Metadata struct {
+	Package string
+}
+
 // LimitedLineReader reads lines from an io.Reader object with a configurable
 // line size limit. Lines exceeding the limit will be truncated, but read
 // completely from the underlying io.Reader.
@@ -14,6 +24,8 @@ type LimitedLineReader struct {
 	limit int
 }
 
+var _ LineReader = &LimitedLineReader{}
+
 // NewLimitedLineReader returns a LimitedLineReader to read lines from r with a
 // maximum line size of limit.
 func NewLimitedLineReader(r io.Reader, limit int) *LimitedLineReader {
@@ -23,14 +35,14 @@ func NewLimitedLineReader(r io.Reader, limit int) *LimitedLineReader {
 // ReadLine returns the next line from the underlying reader. The length of the
 // line will not exceed the configured limit. ReadLine either returns a line or
 // it returns an error, never both.
-func (r *LimitedLineReader) ReadLine() (string, error) {
+func (r *LimitedLineReader) ReadLine() (string, *Metadata, error) {
 	line, isPrefix, err := r.r.ReadLine()
 	if err != nil {
-		return "", err
+		return "", nil, err
 	}
 
 	if !isPrefix {
-		return string(line), nil
+		return string(line), nil, nil
 	}
 
 	// Line is incomplete, keep reading until we reach the end of the line.
@@ -39,7 +51,7 @@ func (r *LimitedLineReader) ReadLine() (string, error) {
 	for isPrefix {
 		line, isPrefix, err = r.r.ReadLine()
 		if err != nil {
-			return "", err
+			return "", nil, err
 		}
 
 		if buf.Len() >= r.limit {
@@ -54,5 +66,5 @@ func (r *LimitedLineReader) ReadLine() (string, error) {
 	if buf.Len() > r.limit {
 		buf.Truncate(r.limit)
 	}
-	return buf.String(), nil
+	return buf.String(), nil, nil
 }

parser/gotest/internal/reader/reader_test.go

@@ -34,7 +34,7 @@ func TestLimitedLineReader(t *testing.T) {
 			input := strings.NewReader(strings.Join([]string{line1, line2}, "\n"))
 			r := NewLimitedLineReader(input, testingLimit)
 
-			got, err := r.ReadLine()
+			got, _, err := r.ReadLine()
 			if err != nil {
 				t.Fatalf("ReadLine() returned error %v", err)
 			}
@@ -47,7 +47,7 @@ func TestLimitedLineReader(t *testing.T) {
 				t.Fatalf("ReadLine() returned incorrect line, got len %d want len %d", len(got), len(want))
 			}
 
-			got, err = r.ReadLine()
+			got, _, err = r.ReadLine()
 			if err != nil {
 				t.Fatalf("ReadLine() returned error %v", err)
 			}
@@ -56,7 +56,7 @@ func TestLimitedLineReader(t *testing.T) {
 				t.Fatalf("ReadLine() returned incorrect line, got len %d want len %d", len(got), len(want))
 			}
 
-			got, err = r.ReadLine()
+			got, _, err = r.ReadLine()
 			if err != io.EOF {
 				t.Fatalf("ReadLine() returned unexpected error, got %v want %v\n", err, io.EOF)
 			}