If Microphone permission is blocked on Mac, show error dialog with instructions to give permission.

Makefile

@@ -47,7 +47,7 @@ ifdef ARCH_MAC
 	SOURCES += $(wildcard src/*.mm src/*/*.mm)
 	SOURCES += dep/osdialog/osdialog_mac.m
 	LDFLAGS += -lpthread -ldl
-	LDFLAGS += -framework SystemConfiguration -framework Cocoa -framework OpenGL -framework IOKit -framework CoreVideo -framework CoreAudio -framework CoreMIDI
+	LDFLAGS += -framework SystemConfiguration -framework Cocoa -framework OpenGL -framework IOKit -framework CoreVideo -framework CoreAudio -framework CoreMIDI -framework AVFoundation
 	LDFLAGS += -Wl,-all_load
 	LDFLAGS += dep/lib/libGLEW.a dep/lib/libglfw3.a dep/lib/libjansson.a dep/lib/libcurl.a dep/lib/libssl.a dep/lib/libcrypto.a -Wl,-load_hidden,dep/lib/libarchive.a -Wl,-load_hidden,dep/lib/libzstd.a dep/lib/libspeexdsp.a dep/lib/libsamplerate.a -Wl,-load_hidden,dep/lib/librtmidi.a -Wl,-load_hidden,dep/lib/librtaudio.a
 endif

adapters/standalone.cpp

@@ -204,6 +204,13 @@ int main(int argc, char* argv[]) {
 	INFO("Initializing audio");
 	audio::init();
 	rtaudioInit();
+#if defined ARCH_MAC
+	if (rtaudioIsMicrophoneBlocked()) {
+		std::string msg = "Rack cannot access audio input because Microphone permission is blocked.";
+		msg += "\n\nGive permission to Rack by opening Apple's System Settings and enabling Privacy & Security > Microphone > " + APP_NAME + " " + APP_VERSION_MAJOR + " " + APP_EDITION_NAME + ".";
+		osdialog_message(OSDIALOG_ERROR, OSDIALOG_OK, msg.c_str());
+	}
+#endif
 	INFO("Initializing MIDI");
 	midi::init();
 	rtmidiInit();

include/rtaudio.hpp

@@ -7,5 +7,10 @@ namespace rack {
 
 PRIVATE void rtaudioInit();
 
+#if defined ARCH_MAC
+/** Checks if Microphone permission is blocked on Mac. */
+bool rtaudioIsMicrophoneBlocked();
+#endif
+
 
 } // namespace rack

src/rtaudio.mm

@@ -0,0 +1,18 @@
+#include <rtaudio.hpp>
+#import <AVFoundation/AVFoundation.h>
+
+namespace rack {
+
+
+bool rtaudioIsMicrophoneBlocked() {
+	// authorizationStatusForMediaType is only available on Mac 10.14+.
+	if (@available(macOS 10.14, *)) {
+		AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeAudio];
+		return status == AVAuthorizationStatusRestricted || status == AVAuthorizationStatusDenied;
+	}
+	// On earlier versions, assume microphone is not blocked.
+	return true;
+}
+
+
+} // namespace rack