Improve CSI sequence error handling

walles · Nov 12, 2023 · bcda779 · bcda779
1 parent 93d01ee
commit bcda779
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Showing 3 changed files with 21 additions and 10 deletions.
diff --git a/m/ansiTokenizer.go b/m/ansiTokenizer.go
@@ -7,7 +7,6 @@ import (
 	"strconv"
 	"strings"
 
-	log "github.com/sirupsen/logrus"
 	"github.com/walles/moar/twin"
 )
 
@@ -426,7 +425,14 @@ type _StyledString struct {
 
 // rawUpdateStyle parses a string of the form "33m" into changes to style. This
 // is what comes after ESC[ in an ANSI SGR sequence.
-func rawUpdateStyle(style twin.Style, escapeSequenceWithoutHeader string) twin.Style {
+func rawUpdateStyle(style twin.Style, escapeSequenceWithoutHeader string) (twin.Style, error) {
+	if len(escapeSequenceWithoutHeader) == 0 {
+		return style, fmt.Errorf("empty escape sequence, expected at least an ending letter")
+	}
+	if escapeSequenceWithoutHeader[len(escapeSequenceWithoutHeader)-1] != 'm' {
+		return style, fmt.Errorf("escape sequence does not end with 'm': %s", escapeSequenceWithoutHeader)
+	}
+
 	numbers := strings.FieldsFunc(escapeSequenceWithoutHeader[:len(escapeSequenceWithoutHeader)-1], func(r rune) bool {
 		return r == ';' || r == ':'
 	})
@@ -488,8 +494,7 @@ func rawUpdateStyle(style twin.Style, escapeSequenceWithoutHeader string) twin.S
 			var color *twin.Color
 			index, color, err = consumeCompositeColor(numbers, index-1)
 			if err != nil {
-				log.Warnf("Foreground: %s", err.Error())
-				return style
+				return style, fmt.Errorf("Foreground: %w", err)
 			}
 			style = style.Foreground(*color)
 		case "39":
@@ -517,8 +522,7 @@ func rawUpdateStyle(style twin.Style, escapeSequenceWithoutHeader string) twin.S
 			var color *twin.Color
 			index, color, err = consumeCompositeColor(numbers, index-1)
 			if err != nil {
-				log.Warnf("Background: %s", err.Error())
-				return style
+				return style, fmt.Errorf("Background: %w", err)
 			}
 			style = style.Background(*color)
 		case "49":
@@ -565,11 +569,11 @@ func rawUpdateStyle(style twin.Style, escapeSequenceWithoutHeader string) twin.S
 			style = style.Background(twin.NewColor16(15))
 
 		default:
-			log.Warnf("Unrecognized ANSI SGR code <%s>", number)
+			return style, fmt.Errorf("Unrecognized ANSI SGR code <%s>", number)
 		}
 	}
 
-	return style
+	return style, nil
 }
 
 // numbers is a list of numbers from a ANSI SGR string

diff --git a/m/ansiTokenizer_test.go b/m/ansiTokenizer_test.go
@@ -232,7 +232,8 @@ func TestConsumeCompositeColorIncomplete24Bit(t *testing.T) {
 }
 
 func TestRawUpdateStyle(t *testing.T) {
-	numberColored := rawUpdateStyle(twin.StyleDefault, "33m")
+	numberColored, err := rawUpdateStyle(twin.StyleDefault, "33m")
+	assert.NilError(t, err)
 	assert.Equal(t, numberColored, twin.StyleDefault.Foreground(twin.NewColor16(3)))
 }
 

diff --git a/m/styledStringSplitter.go b/m/styledStringSplitter.go
@@ -4,6 +4,7 @@ import (
 	"strings"
 	"unicode/utf8"
 
+	log "github.com/sirupsen/logrus"
 	"github.com/walles/moar/twin"
 )
 
@@ -158,7 +159,12 @@ func (s *styledStringSplitter) handleCompleteControlSequence(charAfterEsc rune,
 
 	lastChar := sequence[len(sequence)-1]
 	if lastChar == 'm' {
-		newStyle := rawUpdateStyle(s.inProgressStyle, sequence)
+		newStyle, err := rawUpdateStyle(s.inProgressStyle, sequence)
+		if err != nil {
+			log.Warnf("Failed to parse style %s: %v", sequence, err)
+			return false
+		}
+
 		s.startNewPart(newStyle)
 		return true
 	}