update

utils/ioutils/ioutils.go

@@ -0,0 +1,33 @@
+package ioutils
+
+import (
+	"io"
+	"os"
+
+	"golang.org/x/text/encoding/unicode"
+	"golang.org/x/text/transform"
+)
+
+// UTF8Reader wraps an io.Reader to handle Byte Order Mark (BOM) properly.
+// It strips UTF-8 BOM if present, and converts UTF-16 (LE/BE) to UTF-8.
+// This is particularly useful for reading user-provided text files (like LRC lyrics,
+// playlists) that may have been created on Windows, which often adds BOM markers.
+//
+// Reference: https://en.wikipedia.org/wiki/Byte_order_mark
+func UTF8Reader(r io.Reader) io.Reader {
+	return transform.NewReader(r, unicode.BOMOverride(unicode.UTF8.NewDecoder()))
+}
+
+// UTF8ReadFile reads the named file and returns its contents as a byte slice,
+// automatically handling BOM markers. It's similar to os.ReadFile but strips
+// UTF-8 BOM and converts UTF-16 encoded files to UTF-8.
+func UTF8ReadFile(filename string) ([]byte, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	reader := UTF8Reader(file)
+	return io.ReadAll(reader)
+}

utils/ioutils/ioutils_test.go

@@ -0,0 +1,117 @@
+package ioutils
+
+import (
+	"bytes"
+	"io"
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestIOUtils(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "IO Utils Suite")
+}
+
+var _ = Describe("UTF8Reader", func() {
+	Context("when reading text with UTF-8 BOM", func() {
+		It("strips the UTF-8 BOM marker", func() {
+			// UTF-8 BOM is EF BB BF
+			input := []byte{0xEF, 0xBB, 0xBF, 'h', 'e', 'l', 'l', 'o'}
+			reader := UTF8Reader(bytes.NewReader(input))
+
+			output, err := io.ReadAll(reader)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(string(output)).To(Equal("hello"))
+		})
+
+		It("strips UTF-8 BOM from multi-line text", func() {
+			// Test with the actual LRC file format
+			input := []byte{0xEF, 0xBB, 0xBF, '[', '0', '0', ':', '0', '0', '.', '0', '0', ']', ' ', 't', 'e', 's', 't'}
+			reader := UTF8Reader(bytes.NewReader(input))
+
+			output, err := io.ReadAll(reader)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(string(output)).To(Equal("[00:00.00] test"))
+		})
+	})
+
+	Context("when reading text without BOM", func() {
+		It("passes through unchanged", func() {
+			input := []byte("hello world")
+			reader := UTF8Reader(bytes.NewReader(input))
+
+			output, err := io.ReadAll(reader)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(string(output)).To(Equal("hello world"))
+		})
+	})
+
+	Context("when reading UTF-16 LE encoded text", func() {
+		It("converts to UTF-8 and strips BOM", func() {
+			// UTF-16 LE BOM (FF FE) followed by "hi" in UTF-16 LE
+			input := []byte{0xFF, 0xFE, 'h', 0x00, 'i', 0x00}
+			reader := UTF8Reader(bytes.NewReader(input))
+
+			output, err := io.ReadAll(reader)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(string(output)).To(Equal("hi"))
+		})
+	})
+
+	Context("when reading UTF-16 BE encoded text", func() {
+		It("converts to UTF-8 and strips BOM", func() {
+			// UTF-16 BE BOM (FE FF) followed by "hi" in UTF-16 BE
+			input := []byte{0xFE, 0xFF, 0x00, 'h', 0x00, 'i'}
+			reader := UTF8Reader(bytes.NewReader(input))
+
+			output, err := io.ReadAll(reader)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(string(output)).To(Equal("hi"))
+		})
+	})
+
+	Context("when reading empty content", func() {
+		It("returns empty string", func() {
+			reader := UTF8Reader(bytes.NewReader([]byte{}))
+
+			output, err := io.ReadAll(reader)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(string(output)).To(Equal(""))
+		})
+	})
+})
+
+var _ = Describe("UTF8ReadFile", func() {
+	Context("when reading a file with UTF-8 BOM", func() {
+		It("strips the BOM marker", func() {
+			// Use the actual fixture from issue #4631
+			contents, err := UTF8ReadFile("../../tests/fixtures/bom-test.lrc")
+			Expect(err).ToNot(HaveOccurred())
+
+			// Should NOT start with BOM
+			Expect(contents[0]).ToNot(Equal(byte(0xEF)))
+			// Should start with '['
+			Expect(contents[0]).To(Equal(byte('[')))
+			Expect(string(contents)).To(HavePrefix("[00:00.00]"))
+		})
+	})
+
+	Context("when reading a file without BOM", func() {
+		It("reads the file normally", func() {
+			contents, err := UTF8ReadFile("../../tests/fixtures/test.lrc")
+			Expect(err).ToNot(HaveOccurred())
+
+			// Should contain the expected content
+			Expect(string(contents)).To(ContainSubstring("We're no strangers to love"))
+		})
+	})
+
+	Context("when reading a non-existent file", func() {
+		It("returns an error", func() {
+			_, err := UTF8ReadFile("../../tests/fixtures/nonexistent.lrc")
+			Expect(err).To(HaveOccurred())
+		})
+	})
+})