add timeout to getAudioDevice

Co-authored-by: edisionnano <samantas5855@gmail.com>

CMakeLists.txt

@@ -1,11 +1,16 @@
 cmake_minimum_required(VERSION 3.0)
 project(discord-screenaudio)
 
+include(version.cmake)
+determine_version("${CMAKE_CURRENT_SOURCE_DIR}" DISCORD_SCEENAUDIO)
+add_definitions( -DDISCORD_SCEENAUDIO_VERSION_FULL="${DISCORD_SCEENAUDIO_VERSION_FULL}" )
+
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_AUTOMOC ON)
 set(CMAKE_AUTORCC ON)
 set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DDEBUG")
+string(TIMESTAMP TIMESTAMP %s)
 # set(CMAKE_AUTOUIC ON)
 
 find_package(Qt5 CONFIG REQUIRED COMPONENTS 
@@ -13,6 +18,12 @@ find_package(Qt5 CONFIG REQUIRED COMPONENTS
   WebEngineWidgets
 )
 
+option(KF5NOTIFICATIONS "Use KF5Notifications for enhanced system notifications" ON)
+if(KF5NOTIFICATIONS)
+  add_definitions( -DKF5NOTIFICATIONS )
+  find_package(KF5Notifications)
+endif()
+
 set(discord-screenaudio_SRC
   src/main.cpp
   src/mainwindow.cpp
@@ -47,5 +58,13 @@ add_executable(discord-screenaudio ${discord-screenaudio_SRC})
 
 target_link_libraries(discord-screenaudio Qt5::Widgets Qt5::WebEngineWidgets rohrkabel)
 
+if(KF5NOTIFICATIONS)
+  target_link_libraries(discord-screenaudio KF5::Notifications)
+  install(FILES assets/discord-screenaudio.notifyrc DESTINATION ${CMAKE_INSTALL_PREFIX}/share/knotifications5)
+endif()
+
 install(TARGETS discord-screenaudio DESTINATION bin)
-install(PROGRAMS assets/discord-screenaudio.desktop DESTINATION ${CMAKE_INSTALL_PREFIX}/share/applications)
+install(FILES assets/de.shorsh.discord-screenaudio.png DESTINATION ${CMAKE_INSTALL_PREFIX}/share/icons/hicolor/256x256/apps)
+install(PROGRAMS assets/de.shorsh.discord-screenaudio.desktop DESTINATION ${CMAKE_INSTALL_PREFIX}/share/applications)
+configure_file(assets/de.shorsh.discord-screenaudio.metainfo.xml.in de.shorsh.discord-screenaudio.metainfo.xml)
+install(FILES ${CMAKE_BINARY_DIR}/de.shorsh.discord-screenaudio.metainfo.xml DESTINATION ${CMAKE_INSTALL_PREFIX}/share/metainfo)

README.md

@@ -9,17 +9,36 @@ of [@edisionnano](https://github.com/edisionnano) and the
 
 ![Screenshot_20220718_194357](https://user-images.githubusercontent.com/48161361/179571245-11ea05f3-fb5e-4aef-9132-2736e122ef04.png)
 
+The purpose of this project is **not** to provide an alternative to the original
+Discord client. Rather, it should be used in addition to the original client in
+case you want to stream something, maybe used with a second account. For
+anything else, this client has way too many things that work less well than in
+the original client.
+
+Technically this could be against
+[Discord's TOS](https://discord.com/terms#software-in-discord%E2%80%99s-services),
+so be warned. Discord probably won't ban you for using this, but if they do I
+told you and it's not my fault.
+
 ## Known Issues
 
 - Only works with **PipeWire**
-- Only works on **X11**
-- Can only share primary screen (no other screens or specific applications) (see [#1](https://github.com/maltejur/discord-screenaudio/issues/1))
+- Can only share primary screen on X11 (no other screens or specific applications)
+  (see [#1](https://github.com/maltejur/discord-screenaudio/issues/1))
 
 ## Installation
 
-If you are using Arch, you can build and install
-[from the AUR](https://aur.archlinux.org/packages/discord-screenaudio). If you
-aren't, you will have to [build it yourself](#building-from-source).
+You have multiple options:
+
+- Install the Flatpak (recommended):
+  `flatpak install de.shorsh.discord-screenaudio`
+- If you are on Arch, you can build and install
+  [`discord-screenaudio`](https://aur.archlinux.org/packages/discord-screenaudio)
+  from the AUR
+- If you are on openSUSE, you can use the
+  [Open Build Service package](https://software.opensuse.org/download.html?project=home%3AVortexAcherontic&package=discord-screenaudio)
+  by [@VortexAcherontic](https://github.com/VortexAcherontic)
+- You can [build it yourself](#building-from-source)
 
 ## Building from Source
 
@@ -27,16 +46,23 @@ aren't, you will have to [build it yourself](#building-from-source).
 
 - Basic building tools
 - CMake
-- Qt5 and QtWebEngine
+- Qt5, QtWebEngine and Kf5Notifications
 - **PipeWire** (it currently doesn't work with PulseAudio)
 - Git
 
 On Debian:
-`apt install -y build-essential cmake qtbase5-dev qtwebengine5-dev pkg-config libpipewire-0.3-dev git`
+`apt install -y build-essential cmake qtbase5-dev qtwebengine5-dev libkf5notifications-dev pkg-config libpipewire-0.3-dev git`
 
 ### Building
 
-To build the program, run this in the source directory:
+First, clone the repository:
+
+```bash
+git clone https://github.com/maltejur/discord-screenaudio.git
+cd discord-screenaudio
+```
+
+Then, to build the program, run this in the source directory:
 
 ```bash
 cmake -B build

assets/de.shorsh.discord-screenaudio.desktop

@@ -2,5 +2,5 @@
 Type=Application
 Name=discord-screenaudio
 Exec=discord-screenaudio
-Icon=discord
+Icon=de.shorsh.discord-screenaudio
 Terminal=false

assets/de.shorsh.discord-screenaudio.metainfo.xml.in

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<component type="desktop-application">
+  <id>de.shorsh.discord-screenaudio</id>
+  <metadata_license>CC0-1.0</metadata_license>
+  <project_license>GPL-3.0+</project_license>
+  <name>discord-screenaudio</name>
+  <releases>
+    <release version="${DISCORD_SCEENAUDIO_VERSION_FULL}" timestamp="${TIMESTAMP}" />
+  </releases>
+
+  <summary>A very WIP custom discord client that supports streaming with audio on Linux</summary>
+
+  <description>
+    <p>A very WIP custom discord client that supports streaming with audio on Linux, made possible by the great work of @edisionnano and the Rohrkabel library by @Curve.</p>
+    <p>The purpose of this project is not to provide an alternative to the original Discord client. Rather, it should be used in addition to the original client in case you want to stream something, maybe used with a second account. For anything else, this client has way too many things that work less well than in the original client.</p>
+    <p>Technically this could be against Discord's TOS, so be warned. Discord probably won't ban you for using this, but if they do I told you and it's not my fault.</p>
+    <p>Known issues:<ul><li>Only works with PipeWire</li><li>Can only share primary screen on X11</li></ul></p>
+  </description>
+
+  <launchable type="desktop-id">
+    de.shorsh.discord-screenaudio.desktop
+  </launchable>
+
+  <screenshots>
+    <screenshot type="default">
+      <image>
+        https://user-images.githubusercontent.com/48161361/179571245-11ea05f3-fb5e-4aef-9132-2736e122ef04.png
+      </image>
+    </screenshot>
+  </screenshots>
+
+  <url type="homepage">https://github.com/maltejur/discord-screenaudio</url>
+
+  <provides>
+    <binary>discord-screenaudio</binary>
+  </provides>
+
+  <content_rating type="oars-1.0">
+    <content_attribute id="social-chat">intense</content_attribute>
+    <content_attribute id="social-info">intense</content_attribute>
+    <content_attribute id="social-audio">intense</content_attribute>
+    <content_attribute id="social-contacts">intense</content_attribute>
+    <content_attribute id="money-purchasing">mild</content_attribute>
+  </content_rating>
+</component>

assets/discord-screenaudio.notifyrc

@@ -0,0 +1,8 @@
+[Global]
+IconName=de.shorsh.discord-screenaudio
+Name=discord-screenaudio
+DesktopEntry=de.shorsh.discord-screenaudio.desktop
+
+[Event/discordNotification]
+Name=Discord Notification
+Action=Popup

assets/userscript.js

@@ -3,10 +3,15 @@
 navigator.mediaDevices.chromiumGetDisplayMedia =
   navigator.mediaDevices.getDisplayMedia;
 
+function sleep(ms) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}
+
 const getAudioDevice = async (nameOfAudioDevice) => {
   await navigator.mediaDevices.getUserMedia({
     audio: true,
   });
+  await sleep(500);
   let devices = await navigator.mediaDevices.enumerateDevices();
   let audioDevice = devices.find(({ label }) => label === nameOfAudioDevice);
   return audioDevice;
@@ -81,11 +86,16 @@ setInterval(() => {
     });
     hiddenElements.length = 0;
   } else {
-    for (const el of document.querySelectorAll(
-      '[aria-label="Share Your Screen"]'
-    )) {
+    for (const el of [
+      document.getElementsByClassName("actionButtons-2vEOUh")?.[0]?.children[1],
+      document.querySelector(
+        ".wrapper-3t3Yqv > div > div > div > div > .controlButton-2PMNom"
+      ),
+    ]) {
+      if (!el) continue;
+      if (el.classList.contains("discord-screenaudio-cloned")) continue;
+      el.classList.add("discord-screenaudio-cloned");
       elClone = el.cloneNode(true);
-      elClone.ariaLabel = "Share Your Screen with Audio";
       elClone.title = "Share Your Screen with Audio";
       elClone.addEventListener("click", () => {
         console.log("!discord-screenaudio-start-stream");
@@ -117,9 +127,10 @@ setInterval(() => {
   ) {
     for (const el of document.getElementsByClassName("info-3pQQBb")) {
       const aboutEl = document.createElement("div");
-      aboutEl.innerText = "discord-screenaudio v1.0.0-rc.6";
+      aboutEl.innerText = `discord-screenaudio ${window.discordScreenaudioVersion}`;
       aboutEl.style.fontSize = "12px";
       aboutEl.style.color = "var(--text-muted)";
+      aboutEl.style.textTransform = "none";
       aboutEl.classList.add("dirscordScreenaudioAboutText");
       el.appendChild(aboutEl);
     }
@@ -129,3 +140,7 @@ setInterval(() => {
   document.getElementById("manage-streams-change-windows")?.remove();
   document.querySelector(`[aria-label="Stream Settings"]`)?.remove();
 }, 500);
+
+// Fix for broken discord notifications after restart
+// (https://github.com/maltejur/discord-screenaudio/issues/17)
+Notification.requestPermission();

resources.qrc

@@ -2,5 +2,6 @@
 <RCC>
   <qresource>
     <file>assets/userscript.js</file>
+    <file>assets/de.shorsh.discord-screenaudio.png</file>
   </qresource>
 </RCC>

src/discordpage.cpp

@@ -17,6 +17,11 @@ DiscordPage::DiscordPage(QWidget *parent) : QWebEnginePage(parent) {
   connect(this, &QWebEnginePage::featurePermissionRequested, this,
           &DiscordPage::featurePermissionRequested);
 
+  connect(this, &QWebEnginePage::loadStarted, [=]() {
+    runJavaScript(QString("window.discordScreenaudioVersion = '%1';")
+                      .arg(QApplication::applicationVersion()));
+  });
+
   settings()->setAttribute(QWebEngineSettings::ScreenCaptureEnabled, true);
   settings()->setAttribute(QWebEngineSettings::JavascriptCanOpenWindows, true);
   settings()->setAttribute(QWebEngineSettings::AllowRunningInsecureContent,
@@ -26,10 +31,12 @@ DiscordPage::DiscordPage(QWidget *parent) : QWebEnginePage(parent) {
   settings()->setAttribute(QWebEngineSettings::FullScreenSupportEnabled, true);
   settings()->setAttribute(QWebEngineSettings::PlaybackRequiresUserGesture,
                            false);
+  settings()->setAttribute(QWebEngineSettings::JavascriptCanOpenWindows, false);
 
   setUrl(QUrl("https://discord.com/app"));
 
   injectScript(":/assets/userscript.js");
+  injectVersion(QApplication::applicationVersion());
 
   connect(&m_streamDialog, &StreamDialog::requestedStreamStart, this,
           &DiscordPage::startStream);
@@ -58,6 +65,20 @@ void DiscordPage::injectScript(QString source) {
   }
 }
 
+void DiscordPage::injectVersion(QString version) {
+  QWebEngineScript script;
+
+  auto code = QString("window.discordScreenaudioVersion = '%1';").arg(version);
+
+  script.setSourceCode(code);
+  script.setName("version.js");
+  script.setWorldId(QWebEngineScript::MainWorld);
+  script.setInjectionPoint(QWebEngineScript::DocumentCreation);
+  script.setRunsOnSubFrames(false);
+
+  scripts().insert(script);
+}
+
 void DiscordPage::featurePermissionRequested(const QUrl &securityOrigin,
                                              QWebEnginePage::Feature feature) {
   // Allow every permission asked
@@ -77,7 +98,6 @@ void DiscordPage::featurePermissionRequested(const QUrl &securityOrigin,
 bool DiscordPage::acceptNavigationRequest(const QUrl &url,
                                           QWebEnginePage::NavigationType type,
                                           bool isMainFrame) {
-  qDebug() << url;
   if (type == QWebEnginePage::NavigationTypeLinkClicked) {
     QDesktopServices::openUrl(url);
     return false;
@@ -85,6 +105,18 @@ bool DiscordPage::acceptNavigationRequest(const QUrl &url,
   return true;
 };
 
+bool ExternalPage::acceptNavigationRequest(const QUrl &url,
+                                           QWebEnginePage::NavigationType type,
+                                           bool isMainFrame) {
+  QDesktopServices::openUrl(url);
+  deleteLater();
+  return false;
+}
+
+QWebEnginePage *DiscordPage::createWindow(QWebEnginePage::WebWindowType type) {
+  return new ExternalPage;
+}
+
 void DiscordPage::stopVirtmic() {
   if (m_virtmicProcess.state() == QProcess::Running) {
     qDebug() << "[virtmic] Stopping Virtmic";

src/discordpage.h

@@ -4,6 +4,7 @@
 #include "virtmic.h"
 
 #include <QProcess>
+#include <QWebEngineFullScreenRequest>
 #include <QWebEnginePage>
 
 class DiscordPage : public QWebEnginePage {
@@ -18,11 +19,13 @@ private:
   bool acceptNavigationRequest(const QUrl &url,
                                QWebEnginePage::NavigationType type,
                                bool isMainFrame) override;
+  QWebEnginePage *createWindow(QWebEnginePage::WebWindowType type) override;
   void
   javaScriptConsoleMessage(QWebEnginePage::JavaScriptConsoleMessageLevel level,
                            const QString &message, int lineNumber,
                            const QString &sourceID) override;
   void injectScript(QString source);
+  void injectVersion(QString version);
   void stopVirtmic();
   void startVirtmic(QString target);
 
@@ -31,3 +34,15 @@ private Q_SLOTS:
                                   QWebEnginePage::Feature feature);
   void startStream(QString target, uint width, uint height, uint frameRate);
 };
+
+// Will immediately get destroyed again but is needed for navigation to
+// target="_blank" links, since QWebEnginePage::newWindowRequested is
+// only available sinec Qt 6.3.
+class ExternalPage : public QWebEnginePage {
+  Q_OBJECT
+
+private:
+  bool acceptNavigationRequest(const QUrl &url,
+                               QWebEnginePage::NavigationType type,
+                               bool isMainFrame) override;
+};

src/main.cpp

@@ -1,3 +1,5 @@
+#include "main.h"
+
 #include "mainwindow.h"
 #include "virtmic.h"
 
@@ -7,7 +9,10 @@
 int main(int argc, char *argv[]) {
   QApplication app(argc, argv);
   QApplication::setApplicationName("discord-screenaudio");
-  QApplication::setApplicationVersion("1.0.0-rc.6");
+  QApplication::setWindowIcon(
+      QIcon(":assets/de.shorsh.discord-screenaudio.png"));
+  QApplication::setApplicationVersion(DISCORD_SCEENAUDIO_VERSION_FULL);
+  QApplication::setDesktopFileName("de.shorsh.discord-screenaudio");
 
   QCommandLineParser parser;
   parser.setApplicationDescription(
@@ -17,16 +22,24 @@ int main(int argc, char *argv[]) {
   QCommandLineOption virtmicOption("virtmic", "Start the Virtual Microphone",
                                    "target");
   parser.addOption(virtmicOption);
-#ifdef DEBUG
-  parser.addOption(QCommandLineOption(
-      "remote-debugging-port", "Chromium Remote Debugging Port", "port"));
-#endif
+  QCommandLineOption degubOption("remote-debugging",
+                                 "Open Chromium Remote Debugging on port 9222");
+  parser.addOption(degubOption);
   parser.process(app);
 
   if (parser.isSet(virtmicOption)) {
     Virtmic::start(parser.value(virtmicOption));
   }
 
+  qputenv("QTWEBENGINE_CHROMIUM_FLAGS",
+          "--enable-features=WebRTCPipeWireCapturer " +
+              qgetenv("QTWEBENGINE_CHROMIUM_FLAGS"));
+
+  if (parser.isSet(degubOption))
+    qputenv("QTWEBENGINE_CHROMIUM_FLAGS",
+            "--remote-debugging-port=9222 " +
+                qgetenv("QTWEBENGINE_CHROMIUM_FLAGS"));
+
   MainWindow w;
   w.show();
 

src/main.h

@@ -0,0 +1,6 @@
+#pragma once
+
+#include <QString>
+
+int main(int argc, char *argv[]);
+void addToEnvVar(const char *var, const char *val);

src/mainwindow.cpp

@@ -1,6 +1,10 @@
 #include "mainwindow.h"
 #include "virtmic.h"
 
+#ifdef KF5NOTIFICATIONS
+#include <KNotification>
+#endif
+
 #include <QApplication>
 #include <QColor>
 #include <QComboBox>
@@ -11,6 +15,8 @@
 #include <QSpacerItem>
 #include <QThread>
 #include <QUrl>
+#include <QWebEngineNotification>
+#include <QWebEngineProfile>
 #include <QWebEngineScript>
 #include <QWebEngineScriptCollection>
 #include <QWebEngineSettings>
@@ -23,8 +29,42 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) {
 }
 
 void MainWindow::setupWebView() {
-  m_webView = new QWebEngineView(this);
   auto page = new DiscordPage(this);
+  connect(page, &QWebEnginePage::fullScreenRequested, this,
+          &MainWindow::fullScreenRequested);
+
+  m_webView = new QWebEngineView(this);
   m_webView->setPage(page);
+
+#ifdef KF5NOTIFICATIONS
+  QWebEngineProfile::defaultProfile()->setNotificationPresenter(
+      [&](std::unique_ptr<QWebEngineNotification> notificationInfo) {
+        KNotification *notification = new KNotification("discordNotification");
+        notification->setTitle(notificationInfo->title());
+        notification->setText(notificationInfo->message());
+        notification->setPixmap(QPixmap::fromImage(notificationInfo->icon()));
+        notification->setDefaultAction("View");
+        connect(notification, &KNotification::defaultActivated,
+                [&, notificationInfo = std::move(notificationInfo)]() {
+                  notificationInfo->click();
+                  activateWindow();
+                });
+        notification->sendEvent();
+      });
+#endif
+
   setCentralWidget(m_webView);
 }
+
+void MainWindow::fullScreenRequested(
+    QWebEngineFullScreenRequest fullScreenRequest) {
+  fullScreenRequest.accept();
+  if (fullScreenRequest.toggleOn()) {
+    m_wasMaximized = isMaximized();
+    showFullScreen();
+  } else {
+    m_wasMaximized ? showMaximized() : showNormal();
+  }
+}
+
+void MainWindow::closeEvent(QCloseEvent *event) { QApplication::quit(); }

src/mainwindow.h

@@ -21,4 +21,9 @@ private:
   QWebEngineView *m_webView;
   QWebEngineProfile *prepareProfile();
   DiscordPage *m_discordPage;
+  void closeEvent(QCloseEvent *event) override;
+  bool m_wasMaximized;
+
+private Q_SLOTS:
+  void fullScreenRequested(QWebEngineFullScreenRequest fullScreenRequest);
 };

src/streamdialog.cpp

@@ -13,6 +13,7 @@ StreamDialog::StreamDialog() : QWidget() {
   setAttribute(Qt::WA_QuitOnClose, false);
 
   auto layout = new QVBoxLayout(this);
+  layout->setSizeConstraint(QLayout::SetFixedSize);
 
   auto targetLabel = new QLabel(this);
   targetLabel->setText("Which app do you want to stream sound from?");
@@ -57,7 +58,6 @@ StreamDialog::StreamDialog() : QWidget() {
   setLayout(layout);
 
   setWindowTitle("discord-screenaudio Stream Dialog");
-  setFixedSize(0, 0);
 }
 
 void StreamDialog::startStream() {

version.cmake

@@ -0,0 +1,163 @@
+# Copyright (c) 2018-2021 Ribose Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS
+# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+# desired length of commit hash
+set(GIT_REV_LEN 7)
+
+# call git, store output in var (can fail)
+macro(_git var)
+  execute_process(
+    COMMAND "${GIT_EXECUTABLE}" ${ARGN}
+    WORKING_DIRECTORY "${source_dir}"
+    RESULT_VARIABLE _git_ec
+    OUTPUT_VARIABLE ${var}
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+    ERROR_QUIET
+  )
+endmacro()
+
+function(extract_version_info version var_prefix)
+  # extract the main components
+  #   v1.9.0-3-g5b92266+1546836556
+  #   v1.9.0-3-g5b92266-dirty+1546836556
+  string(REGEX MATCH "^v?([0-9]+\\.[0-9]+\\.[0-9]+)(-([0-9]+)-g([0-9a-f]+)(-dirty)?)?(\\+([0-9]+))?$" matches "${version}")
+  if (NOT matches)
+    message(FATAL_ERROR "Failed to extract version components from ${version}.")
+  endif()
+  set(${var_prefix}_VERSION "${CMAKE_MATCH_1}" PARENT_SCOPE) # 1.9.0
+  if (NOT CMAKE_MATCH_3)
+    set(CMAKE_MATCH_3 "0")
+  endif()
+  set(${var_prefix}_VERSION_NCOMMITS "${CMAKE_MATCH_3}" PARENT_SCOPE) # 3
+  if (NOT CMAKE_MATCH_4)
+    set(CMAKE_MATCH_4 "0")
+  endif()
+  set(${var_prefix}_VERSION_GIT_REV "${CMAKE_MATCH_4}" PARENT_SCOPE) # 5b92266
+  if (CMAKE_MATCH_5 STREQUAL "-dirty")
+    set(${var_prefix}_VERSION_IS_DIRTY TRUE PARENT_SCOPE)
+  else()
+    set(${var_prefix}_VERSION_IS_DIRTY FALSE PARENT_SCOPE)
+  endif()
+  # timestamp is optional, default to 0
+  if (NOT CMAKE_MATCH_7)
+    set(CMAKE_MATCH_7 "0")
+  endif()
+  set(${var_prefix}_VERSION_COMMIT_TIMESTAMP "${CMAKE_MATCH_7}" PARENT_SCOPE) # 1546836556
+endfunction()
+
+function(determine_version source_dir var_prefix)
+  set(has_release_tag NO)
+  set(has_version_txt NO)
+  set(local_prefix "_determine_ver")
+  # find out base version via version.txt
+  set(base_version "0.0.0")
+  if (EXISTS "${source_dir}/version.txt")
+    set(has_version_txt YES)
+    file(STRINGS "${source_dir}/version.txt" version_file)
+    extract_version_info("${version_file}" "${local_prefix}")
+    set(base_version "${${local_prefix}_VERSION}")
+    message(STATUS "Found version.txt with ${version_file}")
+  else()
+    message(STATUS "Found no version.txt.")
+  endif()
+  # for GIT_EXECUTABLE
+  find_package(Git)
+  # get a description of the version, something like:
+  #   v1.9.1-0-g38ffe82        (a tagged release)
+  #   v1.9.1-0-g38ffe82-dirty  (a tagged release with local modifications)
+  #   v1.9.0-3-g5b92266        (post-release snapshot)
+  #   v1.9.0-3-g5b92266-dirty  (post-release snapshot with local modifications)
+  _git(version describe --abbrev=${GIT_REV_LEN} --match "v[0-9]*" --long --dirty)
+  if (NOT _git_ec EQUAL 0)
+    # no annotated tags, fake one
+    message(STATUS "Found no annotated tags.")
+    _git(revision rev-parse --short=${GIT_REV_LEN} --verify HEAD)
+    if (_git_ec EQUAL 0)
+      set(version "v${base_version}-0-g${revision}")
+      # check if dirty (this won't detect untracked files, but should be ok)
+      _git(changes diff-index --quiet HEAD --)
+      if (NOT _git_ec EQUAL 0)
+        string(APPEND version "-dirty")
+      endif()
+      # append the commit timestamp of the most recent commit (only
+      # in non-release branches -- typically master)
+      _git(commit_timestamp show -s --format=%ct)
+      if (_git_ec EQUAL 0)
+        string(APPEND version "+${commit_timestamp}")
+      endif()
+    elseif(has_version_txt)
+      # Nothing to get from git - so use version.txt completely
+      set(version "${version_file}")
+    else()
+      # Sad case - no git, no version.txt
+      set(version "v${base_version}")
+    endif()
+  else()
+    set(has_release_tag YES)
+    message(STATUS "Found annotated tag ${version}")
+  endif()
+  extract_version_info("${version}" "${local_prefix}")
+  if ("${has_version_txt}" AND NOT ${base_version} STREQUAL ${local_prefix}_VERSION)
+    message(WARNING "Tagged version ${${local_prefix}_VERSION} doesn't match one from the version.txt: ${base_version}")
+    if (${base_version} VERSION_GREATER ${local_prefix}_VERSION)
+      set(${local_prefix}_VERSION ${base_version})
+    endif()
+  endif()
+  foreach(suffix VERSION VERSION_NCOMMITS VERSION_GIT_REV VERSION_IS_DIRTY VERSION_COMMIT_TIMESTAMP)
+    if (NOT DEFINED ${local_prefix}_${suffix})
+      message(FATAL_ERROR "Unable to determine version.")
+    endif()
+    set(${var_prefix}_${suffix} "${${local_prefix}_${suffix}}" PARENT_SCOPE)
+    message(STATUS "${var_prefix}_${suffix}: ${${local_prefix}_${suffix}}")
+  endforeach()
+  # Set VERSION_SUFFIX and VERSION_FULL. When making changes, be aware that
+  # this is used in packaging as well and will affect ordering.
+  # | state                 | version_full                |
+  # |-----------------------------------------------------|
+  # | exact tag             | 0.9.0                       |
+  # | exact tag, dirty      | 0.9.0+git20180604           |
+  # | after tag             | 0.9.0+git20180604.1.085039f |
+  # | no tag, version.txt   | 0.9.0+git20180604.2ee02af   |
+  # | no tag, no version.txt| 0.0.0+git20180604.2ee02af   |
+  string(TIMESTAMP date "%Y%m%d" UTC)
+  set(version_suffix "")
+  if (NOT ${local_prefix}_VERSION_NCOMMITS EQUAL 0)
+    # 0.9.0+git20150604.4.289818b
+    string(APPEND version_suffix "+git${date}.${${local_prefix}_VERSION_NCOMMITS}.${${local_prefix}_VERSION_GIT_REV}")
+  elseif ((NOT has_release_tag) AND ((NOT has_version_txt) OR ("${base_version}" STREQUAL "0.0.0") OR (NOT "${revision}" STREQUAL "")))
+    # 0.9.0+git20150604.289818b
+    string(APPEND version_suffix "+git${date}.${${local_prefix}_VERSION_GIT_REV}")
+  elseif(${local_prefix}_VERSION_IS_DIRTY)
+    # 0.9.0+git20150604
+    string(APPEND version_suffix "+git${date}")
+  endif()
+  set(version_full "${${local_prefix}_VERSION}${version_suffix}")
+  # set the results
+  set(${var_prefix}_VERSION_SUFFIX "${version_suffix}" PARENT_SCOPE)
+  set(${var_prefix}_VERSION_FULL "${version_full}" PARENT_SCOPE)
+  # for informational purposes
+  message(STATUS "${var_prefix}_VERSION_SUFFIX: ${version_suffix}")
+  message(STATUS "${var_prefix}_VERSION_FULL: ${version_full}")
+endfunction()
+