Protobuf persistance + Readded persistance for ap service

esp32/include/template/stateful_persistence_pb.h

@@ -0,0 +1,134 @@
+#pragma once
+
+#include <FS.h>
+#include <template/stateful_service.h>
+#include <template/state_result.h>
+#include <filesystem.h>
+#include <pb_encode.h>
+#include <pb_decode.h>
+
+/**
+ * Protobuf-based filesystem persistence for StatefulService.
+ *
+ * @tparam T The state type (should be a nanopb-generated struct like api_APSettings)
+ */
+template <class T>
+class FSPersistencePB {
+  public:
+    using ProtoStateReader = std::function<void(const T&, T&)>;
+    // Formats are passed as referenced const (new object), and a reference to local variable we either want to read from or write to
+    using ProtoStateUpdater = std::function<StateUpdateResult(const T&, T&)>;
+
+    FSPersistencePB(ProtoStateReader stateReader, ProtoStateUpdater stateUpdater,
+                    StatefulService<T> *statefulService, const char *filePath,
+                    const pb_msgdesc_t *msgDescriptor, size_t maxSize)
+        : _stateReader(stateReader),
+          _stateUpdater(stateUpdater),
+          _statefulService(statefulService),
+          _filePath(filePath),
+          _msgDescriptor(msgDescriptor),
+          _maxSize(maxSize),
+          _updateHandlerId(0) {
+        enableUpdateHandler();
+    }
+
+    void readFromFS() {
+        File file = _fs->open(_filePath, "r");
+
+        if (file) {
+            size_t fileSize = file.size();
+            if (fileSize > 0 && fileSize <= _maxSize) {
+                uint8_t *buffer = new uint8_t[fileSize];
+                size_t bytesRead = file.read(buffer, fileSize);
+                file.close();
+
+                if (bytesRead == fileSize) {
+                    T protoMsg = {};
+                    pb_istream_t stream = pb_istream_from_buffer(buffer, bytesRead);
+
+                    if (pb_decode(&stream, _msgDescriptor, &protoMsg)) {
+                        _statefulService->updateWithoutPropagation(
+                            [this, &protoMsg](T &state) { return _stateUpdater(protoMsg, state); });
+                        delete[] buffer;
+                        return;
+                    }
+                }
+                delete[] buffer;
+            } else {
+                file.close();
+            }
+        }
+
+        applyDefaults();
+        writeToFS();
+    }
+
+    bool writeToFS() {
+        uint8_t *buffer = new uint8_t[_maxSize];
+        pb_ostream_t stream = pb_ostream_from_buffer(buffer, _maxSize);
+
+        T protoMsg = {};
+        _statefulService->read([this, &protoMsg](const T &state) { _stateReader(state, protoMsg); });
+
+        bool encodeSuccess = pb_encode(&stream, _msgDescriptor, &protoMsg);
+
+        if (!encodeSuccess) {
+            delete[] buffer;
+            return false;
+        }
+
+        mkdirs();
+
+        File file = _fs->open(_filePath, "w");
+        if (!file) {
+            delete[] buffer;
+            return false;
+        }
+
+        size_t written = file.write(buffer, stream.bytes_written);
+        file.close();
+        delete[] buffer;
+
+        return written == stream.bytes_written;
+    }
+
+    void disableUpdateHandler() {
+        if (_updateHandlerId) {
+            _statefulService->removeUpdateHandler(_updateHandlerId);
+            _updateHandlerId = 0;
+        }
+    }
+
+    void enableUpdateHandler() {
+        if (!_updateHandlerId) {
+            _updateHandlerId = _statefulService->addUpdateHandler(
+                [&](const std::string &originId) { writeToFS(); });
+        }
+    }
+
+  private:
+    ProtoStateReader _stateReader;
+    ProtoStateUpdater _stateUpdater;
+    StatefulService<T> *_statefulService;
+    FS *_fs{&ESP_FS};
+    const char *_filePath;
+    const pb_msgdesc_t *_msgDescriptor;
+    size_t _maxSize;
+    HandlerId _updateHandlerId;
+
+    void mkdirs() {
+        std::string path(_filePath);
+        size_t index = 0;
+        while ((index = path.find('/', index + 1)) != std::string::npos) {
+            std::string segment = path.substr(0, index);
+            if (!_fs->exists(segment.c_str())) _fs->mkdir(segment.c_str());
+        }
+    }
+
+  protected:
+    virtual void applyDefaults() {
+        T defaultState = {};
+        _statefulService->updateWithoutPropagation(
+            [this, &defaultState](T &state) { return _stateUpdater(defaultState, state); });
+    }
+};