After commit c018f5fd29 Fenrir is being switched over to go. If you do not want to be part of the testing process, please switch to master.

internal/reader/diagnostics.go

@@ -0,0 +1,96 @@
+// Fenrir console screen reader.
+// Copyright (c) 2026 Storm Dragon
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by the Free
+// Software Foundation, either version 3 of the License, or (at your option)
+// any later version.
+//
+// This program is distributed in the hope that it will be useful, but WITHOUT
+// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+// more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// this program. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.
+
+package reader
+
+import (
+	"slices"
+	"unicode/utf8"
+
+	"git.stormux.org/storm/fenrir/internal/diagnostic"
+	"git.stormux.org/storm/fenrir/internal/presentation"
+	"git.stormux.org/storm/fenrir/internal/screen"
+)
+
+// AttributeChange contains only geometry and appearance, never cell text.
+// End is exclusive. Keep details bounded even during a whole-screen repaint.
+type AttributeChange struct {
+	Row, Start, End int
+	Before, After   screen.Attribute
+}
+
+func (r *Reader) trace_update(previous, next screen.Snapshot, switched bool, pendingInput int, path string, output []presentation.Message) {
+	comparable := previous.Rows == next.Rows && previous.Cols == next.Cols &&
+		next.Rows > 0 && next.Cols > 0 && len(previous.Cells) == next.Rows*next.Cols && len(next.Cells) == len(previous.Cells)
+	previousAttributes := len(previous.Attributes) > 0 && len(previous.Attributes) == len(previous.Cells)
+	nextAttributes := len(next.Attributes) > 0 && len(next.Attributes) == len(next.Cells)
+	textRows, attributeRows := []int{}, []int{}
+	attributeChanges := []AttributeChange{}
+	truncated := false
+	changedCells, changedAttributes := 0, 0
+	if comparable {
+		for row := range next.Rows {
+			if !slices.Equal(previous.Line(row), next.Line(row)) {
+				textRows = append(textRows, row)
+			}
+			rowChanged := false
+			for col := range next.Cols {
+				index := row*next.Cols + col
+				if previous.Cells[index] != next.Cells[index] {
+					changedCells++
+				}
+				if !previousAttributes || !nextAttributes || previous.Attributes[index] == next.Attributes[index] {
+					continue
+				}
+				rowChanged = true
+				changedAttributes++
+				before, after := previous.Attributes[index], next.Attributes[index]
+				last := len(attributeChanges) - 1
+				if last >= 0 && attributeChanges[last].Row == row && attributeChanges[last].End == col &&
+					attributeChanges[last].Before == before && attributeChanges[last].After == after {
+					attributeChanges[last].End++
+				} else if len(attributeChanges) < 32 {
+					attributeChanges = append(attributeChanges, AttributeChange{Row: row, Start: col, End: col + 1, Before: before, After: after})
+				} else {
+					truncated = true
+				}
+			}
+			if rowChanged {
+				attributeRows = append(attributeRows, row)
+			}
+		}
+	}
+	outputLengths := make([]int, len(output))
+	for index, message := range output {
+		outputLengths[index] = utf8.RuneCountInString(message.Text)
+	}
+	diagnostic.Record("reader update",
+		"terminal", next.Terminal, "previous_terminal", previous.Terminal,
+		"generation", next.Generation, "previous_generation", previous.Generation,
+		"active", next.Active, "switched", switched,
+		"size", [2]int{next.Rows, next.Cols}, "previous_size", [2]int{previous.Rows, previous.Cols},
+		"cursor", [2]int{next.X, next.Y}, "previous_cursor", [2]int{previous.X, previous.Y},
+		"mode", r.trackingMode, "automatic", r.automatic, "cursor_echo", r.cursorEcho,
+		"review", r.review.Active(), "pending_typing", pendingInput,
+		"path", path, "comparable", comparable,
+		"text_rows", textRows, "text_cells", changedCells,
+		"previous_attributes", previousAttributes, "attributes", nextAttributes,
+		"attribute_rows", attributeRows, "attribute_cells", changedAttributes,
+		"attribute_changes", attributeChanges,
+		"attribute_changes_truncated", truncated,
+		"messages", len(output), "message_lengths", outputLengths)
+}