C++ WebSocket client for Flipper

Summary:
Introducing a Flipper WebSocket client implemented in C++.
The requirement came from Spark AR (Skylight) as they have a macOS/Linux/Windows clients.

For reviewers:

- This is an implementation of the existing FlipperSocket interface. Effectively, the only type that needs to be reviewed is WebSocketTLSClient.

- BaseClient defined a base class for WebSocketClient and WebSocketTLSClient.

- WebSocketClient is a simplified version of WebSocketTLSClient as there's no TLS configuration.

Reviewed By: mweststrate

Differential Revision: D34081943

fbshipit-source-id: 619a83f5a6783a21069d0f5111d139bb180f9e97

xplat/FlipperWebSocket/BaseClient.h

@@ -0,0 +1,98 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#ifdef FB_SONARKIT_ENABLED
+
+#pragma once
+
+#include <Flipper/FlipperSocket.h>
+#include <Flipper/FlipperSocketProvider.h>
+#include <Flipper/FlipperTransportTypes.h>
+#include <folly/dynamic.h>
+#include <folly/io/async/EventBase.h>
+#include <future>
+#include <memory>
+#include <mutex>
+
+namespace facebook {
+namespace flipper {
+
+class FlipperConnectionManager;
+class ConnectionContextStore;
+class BaseClient {
+ public:
+  enum Status {
+    Unconnected,
+    Connecting,
+    Initializing,
+    Open,
+    ServerNotFound,
+    Failed,
+    Closed
+  };
+  BaseClient(
+      FlipperConnectionEndpoint endpoint,
+      std::unique_ptr<FlipperSocketBasePayload> payload,
+      folly::EventBase* eventBase)
+      : endpoint_(std::move(endpoint)),
+        payload_(std::move(payload)),
+        eventBase_(eventBase) {}
+  BaseClient(
+      FlipperConnectionEndpoint endpoint,
+      std::unique_ptr<FlipperSocketBasePayload> payload,
+      folly::EventBase* eventBase,
+      ConnectionContextStore* connectionContextStore)
+      : endpoint_(std::move(endpoint)),
+        payload_(std::move(payload)),
+        eventBase_(eventBase),
+        connectionContextStore_(connectionContextStore) {}
+
+  BaseClient(const BaseClient&) = delete;
+  BaseClient& operator=(const BaseClient&) = delete;
+
+  virtual ~BaseClient() {}
+
+  Status status() const {
+    return status_;
+  }
+
+  void setEventHandler(SocketEventHandler eventHandler) {
+    eventHandler_ = std::move(eventHandler);
+  }
+
+  void setMessageHandler(SocketMessageHandler messageHandler) {
+    messageHandler_ = std::move(messageHandler);
+  }
+
+  virtual bool connect(FlipperConnectionManager* manager) = 0;
+  virtual void disconnect() = 0;
+
+  virtual void send(
+      const folly::dynamic& message,
+      SocketSendHandler completion) = 0;
+  virtual void send(
+      const std::string& message,
+      SocketSendHandler completion) = 0;
+  virtual void sendExpectResponse(
+      const std::string& message,
+      SocketSendExpectResponseHandler completion) = 0;
+
+ protected:
+  FlipperConnectionEndpoint endpoint_;
+  std::unique_ptr<FlipperSocketBasePayload> payload_;
+  folly::EventBase* eventBase_;
+  ConnectionContextStore* connectionContextStore_;
+
+  SocketEventHandler eventHandler_;
+  SocketMessageHandler messageHandler_;
+  std::atomic<Status> status_;
+};
+
+} // namespace flipper
+} // namespace facebook
+
+#endif