Add instance manager for enforcing single instance

1 files changed, 106 insertions, 0 deletions

diff --git a/src/InstanceManager.cpp b/src/InstanceManager.cpp
new file mode 100644
index 0000000..4fb27f9
--- /dev/null
+++ b/src/InstanceManager.cpp
@@ -0,0 +1,106 @@
+#include <QLocalSocket>
+#include <QtCore>
+#include <cstdlib>
+#include <qnamespace.h>
+
+#include "InstanceManager.hpp"
+
+InstanceManager::InstanceManager() {
+  bool connected = try_server_connection();
+  if (!connected) {
+    server_init();
+  }
+}
+
+void InstanceManager::write_open_urls_to_socket(const QStringList &urls) {
+  if (socket == nullptr)
+    return;
+
+  auto message = urls.join(" ").toStdString();
+  socket->write(message.c_str());
+  socket->write("\n");
+}
+
+void InstanceManager::write_lua_expr_to_socket(const QString &lua_expr) {
+  if (socket == nullptr)
+    return;
+
+  auto message = ("lua " + lua_expr).toStdString();
+  socket->write(message.c_str());
+  socket->write("\n");
+}
+
+void InstanceManager::server_init() {
+  server = new QLocalServer(this);
+  is_server_mode = true;
+
+  connect(server, &QLocalServer::newConnection, this,
+          &InstanceManager::handle_new_connection);
+
+  QLocalServer::removeServer(socket_path);
+  if (!server->listen(socket_path)) {
+    qCritical() << "Unable to start server:" << server->serverError();
+    exit(1); // TODO: Do something else?
+  }
+}
+
+void InstanceManager::send_message() {
+  socket->waitForBytesWritten();
+  socket->close();
+}
+
+void InstanceManager::handle_new_connection() {
+  if (!server->hasPendingConnections())
+    return;
+
+  qDebug() << "New connection";
+  auto *client = server->nextPendingConnection();
+  if (client == nullptr)
+    return;
+
+  connect(client, &QLocalSocket::disconnected, client,
+          &QLocalSocket::deleteLater);
+
+  client->waitForReadyRead();
+  while (client->canReadLine()) {
+    QString data = client->readLine();
+
+    qDebug() << "RECV:" << data;
+    if (data.startsWith("lua ")) {
+      auto lua_expr = data.sliced(4);
+      emit lua_eval_requested(lua_expr);
+    } else {
+      QRegularExpression whitespace("\\s+");
+      auto urls = data.split(whitespace, Qt::SkipEmptyParts);
+      emit urls_open_requested(urls);
+    }
+  }
+
+  client->close();
+}
+
+bool InstanceManager::try_server_connection() {
+  socket = new QLocalSocket(this);
+  socket->connectToServer(socket_path);
+
+  auto connected = socket->waitForConnected(200);
+  if (connected)
+    return true;
+
+  socket->close();
+  socket->deleteLater();
+  socket = nullptr;
+  return false;
+}
+
+InstanceManager::~InstanceManager() {
+  if (socket) {
+    socket->disconnectFromServer();
+    socket->close();
+    socket->deleteLater();
+  }
+  if (server) {
+    server->disconnect();
+    server->deleteLater();
+  }
+}