From d7ae42d3775f88d5cd63fa2f8860bd31e18f981e Mon Sep 17 00:00:00 2001
From: isanae <14251494+isanae@users.noreply.github.com>
Date: Sun, 8 Nov 2020 22:09:42 -0500
Subject: renamed singleinstance.h/cpp to multiprocess.h/cpp

---
 src/multiprocess.cpp | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 src/multiprocess.cpp

(limited to 'src/multiprocess.cpp')

diff --git a/src/multiprocess.cpp b/src/multiprocess.cpp
new file mode 100644
index 00000000..4ce58718
--- /dev/null
+++ b/src/multiprocess.cpp
@@ -0,0 +1,102 @@
+#include "multiprocess.h"
+#include "utility.h"
+#include <report.h>
+#include <log.h>
+#include <QLocalSocket>
+
+static const char s_Key[] = "mo-43d1a3ad-eeb0-4818-97c9-eda5216c29b5";
+static const int s_Timeout = 5000;
+
+using MOBase::reportError;
+
+MOMultiProcess::MOMultiProcess(bool allowMultiple, QObject *parent) :
+  QObject(parent), m_Ephemeral(false), m_OwnsSM(false)
+{
+  m_SharedMem.setKey(s_Key);
+
+  if (!m_SharedMem.create(1)) {
+    if (m_SharedMem.error() == QSharedMemory::AlreadyExists) {
+      if (!allowMultiple) {
+        m_SharedMem.attach();
+        m_Ephemeral = true;
+      }
+    }
+
+    if ((m_SharedMem.error() != QSharedMemory::NoError) &&
+        (m_SharedMem.error() != QSharedMemory::AlreadyExists)) {
+      throw MOBase::MyException(tr("SHM error: %1").arg(m_SharedMem.errorString()));
+    }
+  } else {
+    m_OwnsSM = true;
+  }
+
+  if (m_OwnsSM) {
+    connect(&m_Server, SIGNAL(newConnection()), this, SLOT(receiveMessage()), Qt::QueuedConnection);
+    // has to be called before listen
+    m_Server.setSocketOptions(QLocalServer::WorldAccessOption);
+    m_Server.listen(s_Key);
+  }
+}
+
+
+void MOMultiProcess::sendMessage(const QString &message)
+{
+  if (m_OwnsSM) {
+    // nobody there to receive the message
+    return;
+  }
+  QLocalSocket socket(this);
+
+  bool connected = false;
+  for(int i = 0; i < 2 && !connected; ++i) {
+    if (i > 0) {
+      Sleep(250);
+    }
+
+    // other process may be just starting up
+    socket.connectToServer(s_Key, QIODevice::WriteOnly);
+    connected = socket.waitForConnected(s_Timeout);
+  }
+
+  if (!connected) {
+    reportError(tr("failed to connect to running process: %1").arg(socket.errorString()));
+    return;
+  }
+
+  socket.write(message.toUtf8());
+  if (!socket.waitForBytesWritten(s_Timeout)) {
+    reportError(tr("failed to communicate with running process: %1").arg(socket.errorString()));
+    return;
+  }
+
+  socket.disconnectFromServer();
+  socket.waitForDisconnected();
+}
+
+void MOMultiProcess::receiveMessage()
+{
+  QLocalSocket *socket = m_Server.nextPendingConnection();
+  if (!socket) {
+    return;
+  }
+
+  if (!socket->waitForReadyRead(s_Timeout)) {
+    // check if there are bytes available; if so, it probably means the data was
+    // already received by the time waitForReadyRead() was called and the
+    // connection has been closed
+    const auto av = socket->bytesAvailable();
+
+    if (av <= 0) {
+      MOBase::log::error(
+        "failed to receive data from secondary process: {}",
+        socket->errorString());
+
+      reportError(tr("failed to receive data from secondary process: %1").arg(socket->errorString()));
+      return;
+    }
+  }
+
+  QString message = QString::fromUtf8(socket->readAll().constData());
+  emit messageSent(message);
+  socket->disconnectFromServer();
+}
-- 
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