fix: long lines (#20)

Author: hedhyw

internal/app/app_test.go

@@ -1,6 +1,7 @@
 package app_test
 
 import (
+	"errors"
 	"os"
 	"strings"
 	"testing"
@@ -199,6 +200,21 @@ func TestAppViewResized(t *testing.T) {
 	}
 }
 
+func TestAppViewError(t *testing.T) {
+	t.Parallel()
+
+	appModel := newTestModel(t, assets.ExampleJSONLog())
+
+	// nolint: goerr113 // It is a test.
+	errMsg := errors.New("error description")
+
+	appModel, _ = toAppModel(appModel.Update(errMsg))
+	assert.True(t, appModel.IsErrorShown())
+
+	rendered := appModel.View()
+	assert.Contains(t, rendered, errMsg.Error())
+}
+
 func newTestModel(tb testing.TB, content []byte) app.Model {
 	tb.Helper()
 

internal/pkg/source/source.go

@@ -4,11 +4,18 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"io"
 	"os"
 
 	tea "github.com/charmbracelet/bubbletea"
 )
 
+const (
+	maxLineSize = 8 * 1024 * 1024
+
+	logEntriesEstimateNumber = 256
+)
+
 // LoadLogsFromFile loads json log entries from file.
 func LoadLogsFromFile(path string) func() tea.Msg {
 	return func() (msg tea.Msg) {
@@ -19,22 +26,33 @@ func LoadLogsFromFile(path string) func() tea.Msg {
 
 		defer file.Close()
 
-		scanner := bufio.NewScanner(file)
+		logEntries, err := parseLogEntriesFromReader(file)
+		if err != nil {
+			return fmt.Errorf("parsing from reader: %w", err)
+		}
 
-		logEntries := make(LogEntries, 0, 256)
+		return logEntries.Reverse()
+	}
+}
 
-		for scanner.Scan() {
-			line := scanner.Bytes()
+func parseLogEntriesFromReader(reader io.Reader) (LogEntries, error) {
+	bufReader := bufio.NewReaderSize(reader, maxLineSize)
+	logEntries := make(LogEntries, 0, logEntriesEstimateNumber)
 
-			if len(bytes.TrimSpace(line)) > 0 {
-				logEntries = append(logEntries, ParseLogEntry(line))
+	for {
+		line, _, err := bufReader.ReadLine()
+		if err != nil {
+			if err == io.EOF {
+				break
 			}
-		}
 
-		if err := scanner.Err(); err != nil {
-			return fmt.Errorf("scanning: %w", err)
+			return nil, fmt.Errorf("reading line: %w", err)
 		}
 
-		return logEntries.Reverse()
+		if len(bytes.TrimSpace(line)) > 0 {
+			logEntries = append(logEntries, ParseLogEntry(line))
+		}
 	}
+
+	return logEntries, nil
 }

internal/pkg/source/source_test.go

@@ -1,6 +1,7 @@
 package source_test
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -34,4 +35,18 @@ func TestLoadLogsFromFile(t *testing.T) {
 		_, ok := msg.(error)
 		assert.Truef(t, ok, "actual type: %T", msg)
 	})
+
+	t.Run("large_line", func(t *testing.T) {
+		t.Parallel()
+
+		longLine := strings.Repeat("1", 2*1024*1024)
+		testFile := tests.RequireCreateFile(t, []byte(longLine))
+
+		msg := source.LoadLogsFromFile(testFile)()
+
+		logEntries, ok := msg.(source.LogEntries)
+		if assert.Truef(t, ok, "actual type: %T", msg) {
+			assert.NotEmpty(t, logEntries)
+		}
+	})
 }