Upload Source/Plugin/InstanceRegistry.h

Source/Plugin/InstanceRegistry.h

@@ -0,0 +1,87 @@
+#pragma once
+
+#include <string>
+#include <map>
+#include <fstream>
+#include <cstdio>
+#include "json.hpp"
+#include "Constants.h"
+
+// Header-only instance registry.
+// Stores {channelName: port} in a JSON file at /tmp/pluginbridge-registry.json
+// Multiple PluginBridge instances write to this file (one per track).
+// Atomic writes via write-to-temp + rename (POSIX rename is atomic on same filesystem).
+
+namespace InstanceRegistry {
+
+inline std::map<std::string, int> readAll()
+{
+    std::map<std::string, int> result;
+    std::ifstream file(PluginBridgeConstants::kRegistryPath);
+    if (!file.is_open()) return result;
+
+    try
+    {
+        nlohmann::json j;
+        file >> j;
+        for (auto& [key, val] : j.items())
+        {
+            if (val.is_number_integer())
+                result[key] = val.get<int>();
+        }
+    }
+    catch (...) {}
+
+    return result;
+}
+
+inline void registerInstance(const std::string& channelName, int port)
+{
+    // Read existing
+    auto registry = readAll();
+
+    // Update entry
+    registry[channelName] = port;
+
+    // Write to temp file, then atomic rename
+    std::string tmpPath = std::string(PluginBridgeConstants::kRegistryPath) + ".tmp";
+
+    nlohmann::json j(registry);
+    std::ofstream tmp(tmpPath);
+    if (tmp.is_open())
+    {
+        tmp << j.dump(2);
+        tmp.close();
+        std::rename(tmpPath.c_str(), PluginBridgeConstants::kRegistryPath);
+    }
+}
+
+inline void unregisterInstance(const std::string& channelName)
+{
+    auto registry = readAll();
+
+    auto it = registry.find(channelName);
+    if (it == registry.end()) return;
+
+    registry.erase(it);
+
+    std::string tmpPath = std::string(PluginBridgeConstants::kRegistryPath) + ".tmp";
+
+    if (registry.empty())
+    {
+        // Remove the file entirely
+        std::remove(PluginBridgeConstants::kRegistryPath);
+        return;
+    }
+
+    nlohmann::json j(registry);
+    std::ofstream tmp(tmpPath);
+    if (tmp.is_open())
+    {
+        tmp << j.dump(2);
+        tmp.close();
+        std::rename(tmpPath.c_str(), PluginBridgeConstants::kRegistryPath);
+    }
+}
+
+} // namespace InstanceRegistry