Debugger: Serve a simple log listener WebSocket.

Planning to add more functionality to it, and sharing the reporting port
is possibly not ideal - although it would make discovery easier.

Core/Debugger/WebSocket.cpp

@@ -0,0 +1,127 @@
+// Copyright (c) 2017- PPSSPP Project.
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, version 2.0 or later versions.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License 2.0 for more details.
+
+// A copy of the GPL 2.0 should have been included with the program.
+// If not, see http://www.gnu.org/licenses/
+
+// Official git repository and contact information can be found at
+// https://github.com/hrydgard/ppsspp and http://www.ppsspp.org/.
+
+#include <algorithm>
+#include <string>
+#include "json/json_writer.h"
+#include "net/websocket_server.h"
+#include "Core/Debugger/WebSocket.h"
+#include "Common/LogManager.h"
+
+// TODO: Move this to its own file?
+class DebuggerLogListener : public LogListener {
+public:
+	void Log(const LogMessage &msg) override {
+		std::lock_guard<std::mutex> guard(lock_);
+		messages_[nextMessage_] = msg;
+		nextMessage_++;
+		if (nextMessage_ >= BUFFER_SIZE)
+			nextMessage_ -= BUFFER_SIZE;
+		count_++;
+	}
+
+	std::vector<LogMessage> GetMessages() {
+		std::lock_guard<std::mutex> guard(lock_);
+		int splitPoint;
+		int readCount;
+		if (read_ + BUFFER_SIZE < count_) {
+			// We'll start with our oldest then.
+			splitPoint = nextMessage_;
+			readCount = Count();
+		} else {
+			splitPoint = read_;
+			readCount = count_ - read_;
+		}
+
+		read_ = count_;
+
+		std::vector<LogMessage> results;
+		int splitEnd = std::min(splitPoint + readCount, (int)BUFFER_SIZE);
+		for (int i = splitPoint; i < splitEnd; ++i) {
+			results.push_back(messages_[i]);
+			readCount--;
+		}
+		for (int i = 0; i < readCount; ++i) {
+			results.push_back(messages_[i]);
+		}
+
+		return results;
+	}
+
+	int Count() const {
+		return count_ < BUFFER_SIZE ? count_ : BUFFER_SIZE;
+	}
+
+private:
+	enum { BUFFER_SIZE = 128 };
+	LogMessage messages_[BUFFER_SIZE];
+	std::mutex lock_;
+	int nextMessage_ = 0;
+	int count_ = 0;
+	int read_ = 0;
+};
+
+struct DebuggerLogEvent {
+	std::string header;
+	std::string message;
+	int level;
+	const char *channel;
+
+	operator std::string() {
+		JsonWriter j;
+		j.begin();
+		j.writeString("event", "log");
+		j.writeString("header", header);
+		j.writeString("message", message);
+		j.writeInt("level", level);
+		j.writeString("channel", channel);
+		j.end();
+		return j.str();
+	}
+};
+
+void HandleDebuggerRequest(const http::Request &request) {
+	net::WebSocketServer *ws = net::WebSocketServer::CreateAsUpgrade(request, "debugger.ppsspp.org");
+	if (!ws)
+		return;
+
+	DebuggerLogListener *logListener = new DebuggerLogListener();
+	if (LogManager::GetInstance())
+		LogManager::GetInstance()->AddListener(logListener);
+
+	// TODO: Handle incoming messages.
+	ws->SetTextHandler([&](const std::string &t) {
+		ws->Send(R"({"event":"error","message":"Bad message","level":2})");
+	});
+	ws->SetBinaryHandler([&](const std::vector<uint8_t> &d) {
+		ws->Send(R"({"event":"error","message":"Bad message","level":2})");
+	});
+
+	while (ws->Process(0.1f)) {
+		auto messages = logListener->GetMessages();
+		// TODO: Check for other conditions?
+		for (auto msg : messages) {
+			ws->Send(DebuggerLogEvent{msg.header, msg.msg, msg.level, msg.log});
+		}
+		continue;
+	}
+
+	if (LogManager::GetInstance())
+		LogManager::GetInstance()->RemoveListener(logListener);
+	delete logListener;
+	delete ws;
+}