common: Add C++ version of Apple authorization logic. (#6616)

src/common/CMakeLists.txt

@@ -138,6 +138,13 @@ add_library(citra_common STATIC
     zstd_compression.h
 )
 
+if (APPLE)
+    target_sources(citra_common PUBLIC
+        apple_authorization.h
+        apple_authorization.cpp
+    )
+endif()
+
 if (MSVC)
   target_compile_options(citra_common PRIVATE
     /W4

src/common/apple_authorization.cpp

@@ -0,0 +1,83 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <future>
+#include <objc/message.h>
+#include "common/apple_authorization.h"
+#include "common/logging/log.h"
+
+namespace AppleAuthorization {
+
+// Bindings to Objective-C APIs
+
+using NSString = void;
+using AVMediaType = NSString*;
+enum AVAuthorizationStatus : int {
+    AVAuthorizationStatusNotDetermined = 0,
+    AVAuthorizationStatusRestricted,
+    AVAuthorizationStatusDenied,
+    AVAuthorizationStatusAuthorized,
+};
+
+typedef NSString* (*send_stringWithUTF8String)(Class, SEL, const char*);
+typedef AVAuthorizationStatus (*send_authorizationStatusForMediaType)(Class, SEL, AVMediaType);
+typedef void (*send_requestAccessForMediaType_completionHandler)(Class, SEL, AVMediaType,
+                                                                 void (^callback)(bool));
+
+NSString* StringToNSString(const std::string_view string) {
+    return reinterpret_cast<send_stringWithUTF8String>(objc_msgSend)(
+        objc_getClass("NSString"), sel_registerName("stringWithUTF8String:"), string.data());
+}
+
+AVAuthorizationStatus GetAuthorizationStatus(AVMediaType media_type) {
+    return reinterpret_cast<send_authorizationStatusForMediaType>(objc_msgSend)(
+        objc_getClass("AVCaptureDevice"), sel_registerName("authorizationStatusForMediaType:"),
+        media_type);
+}
+
+void RequestAccess(AVMediaType media_type, void (^callback)(bool)) {
+    reinterpret_cast<send_requestAccessForMediaType_completionHandler>(objc_msgSend)(
+        objc_getClass("AVCaptureDevice"),
+        sel_registerName("requestAccessForMediaType:completionHandler:"), media_type, callback);
+}
+
+static AVMediaType AVMediaTypeAudio = StringToNSString("soun");
+static AVMediaType AVMediaTypeVideo = StringToNSString("vide");
+
+// Authorization Logic
+
+bool CheckAuthorization(AVMediaType type, const std::string_view& type_name) {
+    switch (GetAuthorizationStatus(type)) {
+    case AVAuthorizationStatusNotDetermined: {
+        LOG_INFO(Frontend, "Requesting {} permission.", type_name);
+        __block std::promise<bool> authorization_promise;
+        std::future<bool> authorization_future = authorization_promise.get_future();
+        RequestAccess(type, ^(bool granted) {
+          LOG_INFO(Frontend, "{} permission request result: {}", type_name, granted);
+          authorization_promise.set_value(granted);
+        });
+        return authorization_future.get();
+    }
+    case AVAuthorizationStatusAuthorized:
+        return true;
+    case AVAuthorizationStatusDenied:
+        LOG_WARNING(Frontend,
+                    "{} permission has been denied and must be enabled via System Settings.",
+                    type_name);
+        return false;
+    case AVAuthorizationStatusRestricted:
+        LOG_WARNING(Frontend, "{} permission is restricted by the system.", type_name);
+        return false;
+    }
+}
+
+bool CheckAuthorizationForCamera() {
+    return CheckAuthorization(AVMediaTypeVideo, "Camera");
+}
+
+bool CheckAuthorizationForMicrophone() {
+    return CheckAuthorization(AVMediaTypeAudio, "Microphone");
+}
+
+} // namespace AppleAuthorization

src/common/apple_authorization.h

@@ -0,0 +1,12 @@
+// Copyright 2023 Citra Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+namespace AppleAuthorization {
+
+bool CheckAuthorizationForCamera();
+bool CheckAuthorizationForMicrophone();
+
+} // namespace AppleAuthorization