implement Cocoa event loop and run it in scsynth_main.cpp to show nat…

…ive GUI windows

* added "-e" command line option to enable the event loop (disabled by default)
* added "eventLoop" member to sclangs's ServerOption class
* didn't have to touch WorldOptions!

HelpSource/Classes/ServerOptions.schelp

@@ -140,6 +140,8 @@ A Boolean indicating whether the server should try to lock its memory into physi
 method:: maxLogins
 An Integer indicating the maximum number of clients which can simultaneously receive notifications from the server. When using TCP this is also the maximum number of simultaneous connections. This is also used by the language to split ranges of link::Classes/Node##Nodes::, link::Classes/Buffer##Buffers::, or link::Classes/Bus##Busses::. In multi-client situations you will need to set this to at least the number of clients you wish to allow. This must be the same in the Server instances on every client. The default is 1.
 
+method:: eventLoop
+A Boolean indicating whether Scsynth should run a Cocoa event loop on its main thread to show native GUI windows on macOS (e.g. VST plugin editors). Default is code::false::.
 
 subsection:: Other Instance Methods
 method:: asOptionsString

SCClassLibrary/Common/Control/Server.sc

@@ -55,6 +55,7 @@ ServerOptions {
 	var <>recBufSize;
 
 	var <>bindAddress;
+	var <>eventLoop; // for macOSC
 
 	*initClass {
 		defaultValues = IdentityDictionary.newFrom(
@@ -98,6 +99,7 @@ ServerOptions {
 				recChannels: 2,
 				recBufSize: nil,
 				bindAddress: "127.0.0.1",
+				eventLoop: false, // run Cocoa event loop to show native GUI windows
 			)
 		)
 	}
@@ -222,6 +224,9 @@ ServerOptions {
 		if (maxLogins.notNil, {
 			o = o ++ " -l " ++ maxLogins;
 		});
+		if (eventLoop, {
+			o = o ++ " -e";
+		});
 		^o
 	}
 

common/SC_Apple.hpp

@@ -23,5 +23,18 @@ namespace SC { namespace Apple {
 
 void disableAppNap();
 
+namespace EventLoop {
+    // Setup the main application. This function must be called in the
+    // main thread and before any other calls to Cocoa methods.
+    void setup();
+    // Run the event loop. This function must be called in the main thread.
+    // It blocks until the event loop finishes.
+    void run();
+    // Ask the event loop to stop and terminate the program.
+    // This function can be called from any thread.
+    void quit();
+
+} // EventLoop
+
 } // namespace Apple
 } // namespace SC

common/SC_Apple.mm

@@ -41,5 +41,46 @@ void disableAppNap() {
     }
 }
 
+namespace EventLoop {
+
+void setup() {
+    // create NSApplication and make it the foreground application
+    ProcessSerialNumber psn = {0, kCurrentProcess};
+    TransformProcessType(&psn, kProcessTransformToForegroundApplication);
+    [NSApplication sharedApplication];
+}
+
+void run() {
+#if 0
+    // this doesn't work...
+    [NSApp run];
+#else
+    // Kudos to https://www.cocoawithlove.com/2009/01/demystifying-nsapplication-by.html
+    NSAutoreleasePool *pool =[[NSAutoreleasePool alloc] init];
+
+    [NSApp finishLaunching];
+    while (true) {
+        [pool release];
+        pool = [[NSAutoreleasePool alloc] init];
+        NSEvent *event = [NSApp
+            nextEventMatchingMask:NSAnyEventMask
+            untilDate:[NSDate distantFuture]
+            inMode:NSDefaultRunLoopMode
+            dequeue:YES];
+        if (event) {
+            [NSApp sendEvent:event];
+            [NSApp updateWindows];
+        }
+    }
+    [pool release];
+#endif
+}
+
+void quit() {
+    [NSApp terminate:nil];
+}
+
+} // EventLoop
+
 } // namespace Apple
 } // namespace SC

server/scsynth/CMakeLists.txt

@@ -199,7 +199,8 @@ if (FFTW3F_FOUND)
 endif()
 
 if (APPLE)
-	target_link_libraries(libscsynth "-framework Accelerate -framework CoreServices -framework Foundation")
+	target_link_libraries(libscsynth "-framework Accelerate -framework CoreServices"
+                                        "-framework Foundation -framework Cocoa")
 endif()
 
 if(CMAKE_SYSTEM_NAME MATCHES "Linux")

server/scsynth/scsynth_main.cpp

@@ -33,6 +33,11 @@
 #else
 #    include <sys/wait.h>
 #endif
+#ifdef __APPLE__
+#include "SC_Apple.hpp"
+#include <thread>
+typedef std::thread SC_Thread;
+#endif
 
 #ifdef _WIN32
 
@@ -42,7 +47,6 @@ inline int setlinebuf(FILE* stream) { return setvbuf(stream, (char*)0, _IONBF, 0
 
 #endif
 
-
 void Usage();
 void Usage() {
     WorldOptions defaultOptions;
@@ -80,6 +84,8 @@ void Usage() {
 #ifdef __APPLE__
              "   -I <input-streams-enabled>\n"
              "   -O <output-streams-enabled>\n"
+             "   -e <enable Cocoa event loop>\n"
+             "          This allows UGens to show native GUI windows.\n"
 #endif
 #if (_POSIX_MEMLOCK - 0) >= 200112L
              "   -L enable memory locking\n"
@@ -136,6 +142,10 @@ int main(int argc, char* argv[]) {
         return 1;
     }
 #endif
+#ifdef __APPLE__
+    bool eventLoop = false;
+#endif
+
 
     int udpPortNum = -1;
     int tcpPortNum = -1;
@@ -144,7 +154,7 @@ int main(int argc, char* argv[]) {
     WorldOptions options;
 
     for (int i = 1; i < argc;) {
-        if (argv[i][0] != '-' || argv[i][1] == 0 || strchr("utBaioczblndpmwZrCNSDIOMHvVRUhPL", argv[i][1]) == 0) {
+        if (argv[i][0] != '-' || argv[i][1] == 0 || strchr("utBaioczblndpmwZrCNSDIOeMHvVRUhPL", argv[i][1]) == 0) {
             scprintf("ERROR: Invalid option %s\n", argv[i]);
             Usage();
         }
@@ -250,6 +260,10 @@ int main(int argc, char* argv[]) {
             checkNumArgs(2);
             options.mOutputStreamsEnabled = argv[j + 1];
             break;
+        case 'e':
+            checkNumArgs(1);
+            eventLoop = true;
+            break;
         case 'M':
 #endif
         case 'H':
@@ -315,6 +329,11 @@ int main(int argc, char* argv[]) {
     } else
         options.mSharedMemoryID = 0;
 
+#ifdef __APPLE__
+    if (eventLoop) {
+        SC::Apple::EventLoop::setup();
+    }
+#endif
 
     struct World* world = World_New(&options);
     if (!world)
@@ -357,8 +376,24 @@ int main(int argc, char* argv[]) {
     }
     fflush(stdout);
 
+#ifdef __APPLE__
+    if (eventLoop) {
+        // this thread simply waits for the world to quit,
+        // after which it will ask the main loop to terminate.
+        auto thread = SC_Thread([&]() {
+            World_WaitForQuit(world, true);
+            scprintf("Quit event loop\n");
+            SC::Apple::EventLoop::quit();
+        });
+        thread.detach();
+        scprintf("Start event loop\n");
+        SC::Apple::EventLoop::run();
+    } else {
+        World_WaitForQuit(world, true);
+    }
+#else
     World_WaitForQuit(world, true);
-
+#endif
 
 #ifdef _WIN32
     // clean up winsock