Span inspector (#1296)

* WIP: Add Span-Inspector

* added expansion of input-code

* added span highlighting

* Add highlighting at cursor position

This highlights all output tokens that share the same span
as the text cursor is hovering over.

* Improved errorhandling: show expansion errors in textfield
Expansion erros are now shown directly in the output textfield.

* Fix target-span determination and incorrect highlighting

- Fix incorrect calculation of target span
- Fix false highlighting caused by Pretty Please code manipulation

* Sanitize expanded code in build_html
- Prevents issues with special characters like '<' and '>' breaking the output HTML

* refactor: replaced get_span_data() with map

* add loading indicator to span inspector

* Add "{" and "}" to parsing filter

These tokens are now ignored during parsing because prettyplease
inserts them automatically in certain situations.

* span-inspector: make output scrollable, improve theme support, fix refresh bug

- Make output text area scrollable
- Adjust text color to match the theme
- Fix edge case where text change did not trigger refresh if cursor position stayed the same

* span_inspector: add indication for synthesized tokens

* chore: add license headers and fix rustfmt formatting

* fix: update Cargo.lock to fix test failure with --locked

- Before tests were failing due to an outdated Cargo.lock

* fix: update Cargo.lock to fix test failure with --locked

- Tests were failing due to an outdated Cargo.lock

* fix: cargo test for span-inspector

* chore(clippy): apply Clippy suggestions to improve code quality

* fix: update Cargo.lock

* fix: update Cargo.lock

* chore(span-inspector): optimize crate features of cxx-qt-lib

* chore: reorder line in Cargo.toml for clarity

* chore(span_inspector): changed uri of qml_module

* chore(span-inspector): removed unnecessary threadspawn

* chore(span-inspector): removed unnecessary mutex for cursor_position

* refactor(span-inspector): moved pretty-please filter into a universal function

* refactor(span-inspector): replaced vec<(bool, bool)> with TokenFlag struct

* feat(span-inspector): ensure only the last spawned thread can write to output

* fix(span-inspector) THREAD_COUNT
 - thread_count is no longer a static atomic type, so multiple
   span-inspectors can be used without interferrring their selfs

* refactor(span-inspector): thread_count is now a simple u32

* chore(span-inspector): removed unnecessary use

* Update build.rs after merge

---------

Co-authored-by: Leon Matthes <[email protected]>
Co-authored-by: Quentin Weber <[email protected]>

Author: 3 people

Cargo.lock

@@ -21,6 +21,7 @@ members = [
     "examples/qml_multi_crates/rust/main",
     "examples/qml_multi_crates/rust/sub1",
     "examples/qml_multi_crates/rust/sub2",
+    "examples/span-inspector",
 
     "tests/basic_cxx_only/rust",
     "tests/basic_cxx_qt/rust",

Cargo.toml

@@ -0,0 +1,29 @@
+# SPDX-FileCopyrightText: 2022 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+# SPDX-FileContributor: Leon Matthes <[email protected]>
+# SPDX-FileContributor: Quentin Weber <[email protected]>
+#
+# SPDX-License-Identifier: MIT OR Apache-2.0
+
+[package]
+name = "span-inspector"
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+version.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+cxx.workspace = true
+cxx-qt.workspace = true
+cxx-qt-lib = { workspace = true, features = ["qt_full"] }
+cxx-qt-macro = { workspace = true }
+cxx-qt-gen = { workspace = true }
+proc-macro2.workspace = true
+prettyplease = { version = "0.2", features = ["verbatim"] }
+syn.workspace = true
+
+[build-dependencies]
+cxx-qt-build = { workspace = true, features = ["link_qt_object_files"] }
+
+[lints]
+workspace = true

examples/span-inspector/Cargo.toml

@@ -0,0 +1,20 @@
+// SPDX-FileCopyrightText: 2025 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// SPDX-FileContributor: Leon Matthes <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+use cxx_qt_build::{CxxQtBuilder, QmlModule};
+
+fn main() {
+    let qml_module = QmlModule::new("com.kdab.cxx_qt.span_inspector").qml_file("qml/main.qml");
+    CxxQtBuilder::new_qml_module(qml_module)
+        // Link Qt's Network library
+        // - Qt Core is always linked
+        // - Qt Gui is linked by enabling the qt_gui Cargo feature of cxx-qt-lib.
+        // - Qt Qml is linked by enabling the qt_qml Cargo feature of cxx-qt-lib.
+        // - Qt Qml requires linking Qt Network on macOS
+        .qt_module("Network")
+        .qt_module("Quick")
+        .file("src/inspector.rs")
+        .build();
+}

examples/span-inspector/build.rs

@@ -0,0 +1,63 @@
+// SPDX-FileCopyrightText: 2025 Klarälvdalens Datakonsult AB, a KDAB Group company <[email protected]>
+// SPDX-FileContributor: Leon Matthes <[email protected]>
+//
+// SPDX-License-Identifier: MIT OR Apache-2.0
+
+import QtQuick
+import QtQuick.Controls
+import QtQuick.Window
+import QtQuick.Layouts
+
+import com.kdab.cxx_qt.span_inspector 1.0
+
+ApplicationWindow {
+    id: appWindow
+    color: palette.window
+    property color textColor: color.lightness < 128 * "black", "white"
+    height: 480
+    title: qsTr("Span Inspector")
+    visible: true
+    width: 640
+
+    SpanInspector {
+        id: inspector
+    }
+
+    SplitView {
+        anchors.fill: parent
+        Item {
+            SplitView.preferredWidth: parent.width / 2
+            TextArea {
+                id: inputEdit
+                SplitView.preferredWidth: parent.width / 2
+                wrapMode: TextArea.Wrap
+                anchors.fill: parent
+                clip: true
+                color: appWindow.textColor
+                Component.onCompleted: {
+                    inspector.input = textDocument;
+                    inspector.rebuildOutput(cursorPosition);
+                }
+
+                onCursorPositionChanged: {
+                    inspector.rebuildOutput(cursorPosition);
+                }
+
+                onTextChanged: {
+                    inspector.rebuildOutput(cursorPosition);
+                }
+            }
+        }
+
+        ScrollView {
+            SplitView.preferredWidth: parent.width / 2
+            TextEdit {
+                clip: true
+                color: appWindow.textColor
+                text: "Hello World"
+                readOnly: true
+                Component.onCompleted: inspector.output = textDocument
+            }
+        }
+    }
+}