Fist commit

lib/timbre_core/StateRepository.h

@@ -0,0 +1,75 @@
+#pragma once
+
+#include "Model.h"
+
+namespace timbre_core {
+
+// Persistence is represented only by this small interface.  Implementations
+// may use a file system on the final product, but the domain layer remains
+// portable and has no filesystem dependency.
+class StateRepository {
+public:
+    virtual ~StateRepository() = default;
+
+    // Canonical names used by TimbreService.
+    virtual bool load(AppState& destination) { return read(destination); }
+    virtual bool commit(const AppState& source) { return save(source); }
+
+    // Compatibility hooks for small repositories that naturally use read/write
+    // terminology.  Overriding either pair is sufficient; the defaults above
+    // bridge the two naming conventions without recursion.
+    virtual bool read(AppState& destination) {
+        (void)destination;
+        return false;
+    }
+    virtual bool write(const AppState& source) {
+        (void)source;
+        return false;
+    }
+
+    virtual bool save(const AppState& source) { return write(source); }
+    bool loadState(AppState& destination) { return load(destination); }
+    bool commitState(const AppState& source) { return commit(source); }
+};
+
+class MemoryStateRepository final : public StateRepository {
+public:
+    bool load(AppState& destination) override {
+        if (!loadSucceeds_ || !hasValue_) {
+            return false;
+        }
+        destination = value_;
+        return true;
+    }
+
+    bool commit(const AppState& source) override {
+        ++commitAttempts_;
+        if (!commitSucceeds_) {
+            return false;
+        }
+        value_ = source;
+        hasValue_ = true;
+        ++commitCount_;
+        return true;
+    }
+
+    void seed(const AppState& state) {
+        value_ = state;
+        hasValue_ = true;
+    }
+
+    void setCommitSucceeds(bool succeeds) noexcept { commitSucceeds_ = succeeds; }
+    void setLoadSucceeds(bool succeeds) noexcept { loadSucceeds_ = succeeds; }
+    std::size_t commitAttempts() const noexcept { return commitAttempts_; }
+    std::size_t commitCount() const noexcept { return commitCount_; }
+
+private:
+    AppState value_{};
+    bool hasValue_ = false;
+    bool loadSucceeds_ = true;
+    bool commitSucceeds_ = true;
+    std::size_t commitAttempts_ = 0;
+    std::size_t commitCount_ = 0;
+};
+
+} // namespace timbre_core