Bare bones ROM loading functionality (requires modification of the app container to add ROMs)

iOS/GBLoadROMTableViewController.h

@@ -0,0 +1,5 @@
+#import <UIKit/UIKit.h>
+
+@interface GBLoadROMTableViewController : UITableViewController
+
+@end

iOS/GBLoadROMTableViewController.m

@@ -0,0 +1,42 @@
+#import "GBLoadROMTableViewController.h"
+#import "GBROMManager.h"
+
+@interface GBLoadROMTableViewController ()
+
+@end
+
+@implementation GBLoadROMTableViewController
+
+- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
+{
+    return 1;
+}
+
+- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
+{
+    return [GBROMManager sharedManager].allROMs.count;
+}
+
+
+- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
+{
+    UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:nil];
+    cell.textLabel.text = [GBROMManager sharedManager].allROMs[[indexPath indexAtPosition:1]];
+    
+    return cell;
+}
+
+- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
+{
+    [GBROMManager sharedManager].currentROM = [GBROMManager sharedManager].allROMs[[indexPath indexAtPosition:1]];
+    [self.presentingViewController dismissViewControllerAnimated:true completion:^{
+        [[NSNotificationCenter defaultCenter] postNotificationName:@"GBROMChanged" object:nil];
+    }];
+}
+
+- (BOOL)isModalInPresentation
+{
+    return true;
+}
+
+@end

iOS/GBROMManager.h

@@ -0,0 +1,9 @@
+#import <Foundation/Foundation.h>
+
+@interface GBROMManager : NSObject
++ (instancetype) sharedManager;
+
+@property (readonly) NSArray<NSString *> *allROMs;
+@property (nonatomic) NSString *currentROM;
+@property (readonly) NSString *romFile;
+@end

iOS/GBROMManager.m

@@ -0,0 +1,69 @@
+#import "GBROMManager.h"
+
+@implementation GBROMManager
+{
+    NSString *_romFile;
+}
+
++ (instancetype)sharedManager
+{
+    static dispatch_once_t onceToken;
+    static GBROMManager *manager;
+    dispatch_once(&onceToken, ^{
+        manager = [[self alloc] init];
+    });
+    return manager;
+}
+
+- (instancetype)init
+{
+    self = [super init];
+    if (!self) return nil;
+    self.currentROM = [[NSUserDefaults standardUserDefaults] stringForKey:@"GBLastROM"];
+    return self;
+}
+
+- (void)setCurrentROM:(NSString *)currentROM
+{
+    _romFile = nil;
+    _currentROM = currentROM;
+    if (currentROM && !self.romFile) {
+        _currentROM = nil;
+    }
+    
+    [[NSUserDefaults standardUserDefaults] setObject:_currentROM forKey:@"GBLastROM"];
+}
+
+- (NSString *)romFileForDirectory:(NSString *)romDirectory
+{
+    for (NSString *filename in [NSFileManager.defaultManager enumeratorAtPath:romDirectory]) {
+        if ([@[@"gb", @"gbc", @"isx"] containsObject:filename.pathExtension.lowercaseString]) {
+            return [romDirectory stringByAppendingPathComponent:filename];
+        }
+    }
+    
+    return nil;
+}
+
+- (NSString *)romFile
+{
+    if (_romFile) return _romFile;
+    if (!_currentROM) return nil;
+    NSString *root = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, true).firstObject;
+    NSString *romDirectory = [root stringByAppendingPathComponent:_currentROM];
+    return _romFile = [self romFileForDirectory:romDirectory];
+}
+
+- (NSArray<NSString *> *)allROMs
+{
+    NSMutableArray<NSString *> *ret = [NSMutableArray array];
+    NSString *root = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, true).firstObject;
+    for (NSString *romDirectory in [NSFileManager.defaultManager enumeratorAtPath:root]) {
+        if ([self romFileForDirectory:[root stringByAppendingPathComponent:romDirectory]]) {
+            [ret addObject:romDirectory];
+        }
+    }
+    return ret;
+}
+
+@end

iOS/GBViewController.m

@@ -3,6 +3,8 @@
 #import "GBVerticalLayout.h"
 #import "GBViewMetal.h"
 #import "GBAudioClient.h"
+#import "GBROMManager.h"
+#import "GBLoadROMTableViewController.h"
 #include <Core/gb.h>
 
 @implementation GBViewController
@@ -11,6 +13,7 @@
     GBView *_gbView;
     volatile bool _running;
     volatile bool _stopping;
+    bool _romLoaded;
     GBLayout *_currentLayout;
     GBHorizontalLayout *_horizontalLayout;
     GBVerticalLayout *_verticalLayout;
@@ -138,11 +141,34 @@ static void rumbleCallback(GB_gameboy_t *gb, double amp)
     
     _audioLock = [[NSCondition alloc] init];
     
+    [self loadROM];
+    [[NSNotificationCenter defaultCenter] addObserverForName:@"GBROMChanged"
+                                                      object:nil
+                                                       queue:nil
+                                                  usingBlock:^(NSNotification * _Nonnull note) {
+        [self loadROM];
+        [self start];
+    }];
     return true;
 }
 
+- (void)loadROM
+{
+    GBROMManager *romManager = [GBROMManager sharedManager];
+    if (romManager.romFile) {
+        // Todo: display errors and warnings
+        _romLoaded = GB_load_rom(&_gb, romManager.romFile.fileSystemRepresentation) == 0;
+    }
+}
+
 - (void)applicationDidBecomeActive:(UIApplication *)application
 {
+    if (self.presentedViewController) return;
+    if (!_romLoaded) {
+        [self presentViewController:[[GBLoadROMTableViewController alloc] init]
+                           animated:true
+                         completion:nil];
+    }
     [self start];
 }
 
@@ -253,6 +279,7 @@ static void rumbleCallback(GB_gameboy_t *gb, double amp)
 
 - (void)start
 {
+    if (!_romLoaded) return;
     if (_running) return;
     _running = true;
     [[[NSThread alloc] initWithTarget:self selector:@selector(run) object:nil] start];