better scrollbar in codeblocks + enter anim for delegates

Plugins/ZShell/Llm/codehighlighter.hpp

@@ -43,6 +43,10 @@ namespace ZShell::llm {
 // means "no highlighting" (unknown language or grammar not installed).
 // token is passed back unchanged so the caller can drop results for
 // superseded code; a destroyed target is simply skipped.
+//
+// Successful results are cached by (language, code). A request for
+// unchanged code delivers the cached spans directly, without re-parsing
+// — while a segment streams, only the grown tail is ever re-parsed.
 class CodeHighlighter : public QObject {
 	Q_OBJECT
 	QML_ELEMENT
@@ -76,13 +80,31 @@ class CodeHighlighter : public QObject {
 	// Maps a tree-sitter capture name to a role index (0 = unstyled).
 	[[nodiscard]] static uint8_t roleFor(const char* name, uint32_t length);
 	[[nodiscard]] static const char* roleName(uint8_t role);
+	// Maps a fence language tag to the grammar id (see aliases()).
+	[[nodiscard]] static QString resolveId(const QString& language);
+	[[nodiscard]] static QString cacheKey(const QString& id, const QString& code);
 	// The parsing work; runs on worker threads, so the per-language
 	// state must be initialized under m_stateMutex and is shared as an
 	// immutable object afterwards.
 	[[nodiscard]] QVariantList doHighlight(const QString& code, const QString& language) const;
+	// Exact-match span cache. lookupSpans() runs on the GUI thread,
+	// storeSpans() on worker threads; both take m_cacheMutex.
+	[[nodiscard]] QVariantList lookupSpans(const QString& code, const QString& language) const;
+	void storeSpans(const QString& code, const QString& language,
+	               const QVariantList& spans) const;
+
+	struct SpanCacheEntry {
+		QString code; // re-compared on lookup; a hash collision can
+		             // never deliver the wrong spans
+		QVariantList spans;
+	};
 
 	mutable QHash<QString, std::shared_ptr<const State>> m_states;
 	mutable QMutex m_stateMutex;
+	mutable QHash<QString, SpanCacheEntry> m_spanCache;
+	mutable QStringList m_spanCacheOrder; // LRU order, oldest first
+	mutable int m_spanCacheBytes = 0;
+	mutable QMutex m_cacheMutex;
 	static CodeHighlighter* s_instance;
 };