diff --git a/example_textview_test.go b/example_textview_test.go new file mode 100644 index 0000000..027534e --- /dev/null +++ b/example_textview_test.go @@ -0,0 +1,21 @@ +package tview_test + +import ( + "fmt" + + "github.com/rivo/tview" +) + +func ExampleTextView_BatchWriter() { + tv := tview.NewTextView() + + w := tv.BatchWriter() + defer w.Close() + w.Clear() + fmt.Fprintln(w, "To sit in solemn silence") + fmt.Fprintln(w, "on a dull, dark, dock") + fmt.Println(tv.GetText(false)) + // Output: + // To sit in solemn silence + // on a dull, dark, dock +} diff --git a/textview.go b/textview.go index fa7c662..c4582ec 100644 --- a/textview.go +++ b/textview.go @@ -419,10 +419,20 @@ func (t *TextView) GetScrollOffset() (row, column int) { // Clear removes all text from the buffer. func (t *TextView) Clear() *TextView { + t.Lock() + defer t.Unlock() + + t.clear() + return t +} + +// clear is the internal implementaton of clear. +// It is used by TextViewWriter and anywhere that we need to perform a write +// without locking the buffer. +func (t *TextView) clear() { t.buffer = nil t.recentBytes = nil t.index = nil - return t } // Highlight specifies which regions should be highlighted. If highlight @@ -622,10 +632,18 @@ func (t *TextView) HasFocus() bool { // replaced with TabSize space characters. A "\n" or "\r\n" will be interpreted // as a new line. func (t *TextView) Write(p []byte) (n int, err error) { - // Notify at the end. t.Lock() + defer t.Unlock() + + return t.write(p) +} + +// write is the internal implementation of Write. +// It is used by TextViewWriter and anywhere that we need to perform a write +// without locking the buffer. +func (t *TextView) write(p []byte) (n int, err error) { + // Notify at the end. changed := t.changed - t.Unlock() if changed != nil { defer func() { // We always call the "changed" function in a separate goroutine to avoid @@ -634,9 +652,6 @@ func (t *TextView) Write(p []byte) (n int, err error) { }() } - t.Lock() - defer t.Unlock() - // Copy data over. newBytes := append(t.recentBytes, p...) t.recentBytes = nil @@ -1259,3 +1274,45 @@ func (t *TextView) MouseHandler() func(action MouseAction, event *tcell.EventMou return }) } + +// TextViewWriter is a writer that can be used to write and clear a TextView in +// batches (ie. multiple writes with the lock only being aquired once). +// It should not be instantiated directly and should instead only be created by +// TextView's BatchWriter method. +type TextViewWriter struct { + t *TextView +} + +// Close implements io.Closer for the writer by unlocking the original TextView. +func (w TextViewWriter) Close() error { + w.t.Unlock() + return nil +} + +// Clear removes all text from the buffer. +func (w TextViewWriter) Clear() { + w.t.clear() +} + +// Write implements the io.Writer interface. +// It behaves like the TextView's Write method except that it does not aquire +// the lock. +func (w TextViewWriter) Write(p []byte) (n int, err error) { + return w.t.write(p) +} + +// HasFocus returns whether the underlying TextView has focus. +func (w TextViewWriter) HasFocus() bool { + return w.t.hasFocus +} + +// BatchWriter returns a new writer that can be used to write into the buffer +// but without Locking/Unlocking the buffer on every write. +// The lock will only be aquired once when BatchWriter is called, and will be +// released when the returned writer is Closed. +func (t *TextView) BatchWriter() TextViewWriter { + t.Lock() + return TextViewWriter{ + t: t, + } +}