refactor: split main.cpp into separate files, fix bugs 5-8, 15

src/search_engine.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <QObject>
+#include <QVector>
+#include <QString>
+
+#include <atomic>
+#include <chrono>
+
+#include "search_core.h"
+#include "search_cache.h"
+
+class SearchEngine final : public QObject {
+    Q_OBJECT
+public:
+    explicit SearchEngine(QObject *parent = nullptr) : QObject(parent) {}
+
+public slots:
+    void stop() { cancelled_.store(true, std::memory_order_relaxed); }
+    void clearCache()
+    {
+        cache_.clear();
+        emit cacheCleared();
+    }
+
+    void search(const SearchOptions &o);
+
+signals:
+    void progress(const QString &path, quint64 scanned);
+    void phaseProgress(const QString &phase, quint64 completed, quint64 total);
+    void cacheCleared();
+    void finished(const QVector<FileRecord> &results, const QString &message);
+
+private:
+    QByteArray cachedSha256(const FileRecord &record);
+    bool cachedFileContains(const FileRecord &record, const SearchOptions &o);
+
+    SearchCache cache_;
+    std::atomic<quint64> cacheHits_ = 0;
+    std::atomic<quint64> cacheMisses_ = 0;
+    std::atomic_bool cancelled_ = false;
+    bool cancelledByLimit_ = false;
+};