looper/backends/ui/imgui/file_browser_osx.mm

#include <Foundation/Foundation.h>
#include <Cocoa/Cocoa.h>
#include <UniformTypeIdentifiers/UTCoreTypes.h>
#include <vector>
#include <string>

extern "C++" {
UTType *GetUTIFromExtension(NSString *extension) {
    return [UTType typeWithFilenameExtension:extension];
}
NSMutableArray *ConvertExtensions(std::vector<std::string> input) {
    NSMutableArray *arr = [[[NSMutableArray alloc] init] autorelease];
    for (auto &str : input) {
        UTType *maybeUTI = GetUTIFromExtension([NSString stringWithUTF8String:str.c_str()]);
        if (maybeUTI != nil) {
            [arr addObject:maybeUTI];
        }
    }
    return arr;
}
const char *OpenDialog(std::vector<std::string> fileTypes, std::string initialDirectory)  {
    NSMutableArray *arr = ConvertExtensions(fileTypes);
    NSOpenPanel* openFileDialog = [[[NSOpenPanel alloc] init] autorelease];
    [openFileDialog setCanChooseFiles:YES];
    [openFileDialog setCanChooseDirectories:NO];
    [openFileDialog setAllowsMultipleSelection:NO];
    [openFileDialog setAllowedContentTypes:arr];
    [openFileDialog setDirectoryURL:[NSURL fileURLWithPath:[NSString stringWithUTF8String:initialDirectory.c_str()]]];

    NSModalResponse response = [openFileDialog runModal];
    if (response == NSModalResponseOK) {
        return [[(NSURL*)[[openFileDialog URLs] objectAtIndex:0] path] UTF8String];
    } else {
        return nullptr;
    }
}

const char *SaveDialog(std::vector<std::string> fileTypes, std::string initialDirectory) {
    NSSavePanel *panel = [[[NSSavePanel alloc] init] autorelease];
    [panel setCanCreateDirectories:YES];
    NSMutableArray *arr = ConvertExtensions(fileTypes);
    [panel setAllowedContentTypes:arr];
    [panel setDirectoryURL:[NSURL fileURLWithPath:[NSString stringWithUTF8String:initialDirectory.c_str()]]];

    NSModalResponse response = [panel runModal];
    if (response == NSModalResponseOK) {
        return [[[panel URL] path] UTF8String];
    } else {
        return nullptr;
    }
}
}