More work on LibreOffice support.

internal/atspi/libreoffice.go

@@ -4,6 +4,11 @@
 
 package atspi
 
+import (
+	"strings"
+	"unicode/utf8"
+)
+
 // LibreOfficeContext is bounded, copied metadata from the native owner. It
 // describes Calc's cell and temporary editor objects, without native handles.
 // Presentation and application policy must not query the provider themselves.
@@ -15,6 +20,7 @@ type LibreOfficeContext struct {
 	ContainerFocused bool
 	CellText         string
 	Coordinates      string
+	Formula          string
 }
 
 // IsLibreOfficeProcess uses /proc identity verified by the adapter. An
@@ -22,3 +28,16 @@ type LibreOfficeContext struct {
 func IsLibreOfficeProcess(process string) bool {
 	return process == "soffice.bin"
 }
+
+// Preserve spaces inside formula string literals and keep the beginning when
+// bounding long expressions. Text context's default suffix is for caret lines.
+func sanitizeLibreOfficeFormula(value string) string {
+	value = strings.ToValidUTF8(value, "�")
+	if len(value) > maxSnapshotFieldLength {
+		value = value[:maxSnapshotFieldLength]
+		for !utf8.ValidString(value) {
+			value = value[:len(value)-1]
+		}
+	}
+	return sanitizeTextContext(value)
+}