Allow drag&drop of state files

Cocoa/Document.h

@@ -44,5 +44,6 @@
 -(void) writeMemory:(uint16_t) addr value:(uint8_t)value;
 -(void) performAtomicBlock: (void (^)())block;
 -(void) connectLinkCable:(NSMenuItem *)sender;
+- (bool)loadStateFile:(const char *)path;
 @end
 

Cocoa/Document.m

@@ -1172,12 +1172,12 @@ static unsigned *multiplication_table_for_frequency(unsigned frequency)
     }
 }
 
-- (IBAction)loadState:(id)sender
+- (bool)loadStateFile:(const char *)path
 {
     bool __block success = false;
     NSString *error =
     [self captureOutputForBlock:^{
-        success = GB_load_state(&gb, [[self.fileURL URLByDeletingPathExtension] URLByAppendingPathExtension:[NSString stringWithFormat:@"s%ld", (long)[sender tag] ]].path.UTF8String) == 0;
+        success = GB_load_state(&gb, path) == 0;
     }];
     
     if (!success) {
@@ -1186,6 +1186,12 @@ static unsigned *multiplication_table_for_frequency(unsigned frequency)
     if (error) {
         [GBWarningPopover popoverWithContents:error onWindow:self.mainWindow];
     }
+    return success;
+}
+
+- (IBAction)loadState:(id)sender
+{
+    [self loadStateFile:[[self.fileURL URLByDeletingPathExtension] URLByAppendingPathExtension:[NSString stringWithFormat:@"s%ld", (long)[sender tag] ]].path.UTF8String];
 }
 
 - (IBAction)clearConsole:(id)sender

Cocoa/GBView.m

@@ -142,6 +142,8 @@ static const uint8_t workboy_vk_to_key[] = {
 
 - (void) _init
 {
+    [self registerForDraggedTypes:[NSArray arrayWithObjects: NSPasteboardTypeFileURL, nil]];
+    
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(ratioKeepingChanged) name:@"GBAspectChanged" object:nil];
     tracking_area = [ [NSTrackingArea alloc] initWithRect:(NSRect){}
                                                   options:NSTrackingMouseEnteredAndExited | NSTrackingActiveAlways | NSTrackingInVisibleRect
@@ -626,4 +628,29 @@ static const uint8_t workboy_vk_to_key[] = {
     return image_buffers[(current_buffer + 2) % self.numberOfBuffers];
 }
 
+-(NSDragOperation)draggingEntered:(id<NSDraggingInfo>)sender
+{
+    NSPasteboard *pboard = [sender draggingPasteboard];
+    
+    if ( [[pboard types] containsObject:NSURLPboardType] ) {
+        NSURL *fileURL = [NSURL URLFromPasteboard:pboard];
+        if (GB_is_stave_state(fileURL.fileSystemRepresentation)) {
+            return NSDragOperationGeneric;
+        }
+    }
+    return NSDragOperationNone;
+}
+
+-(BOOL)performDragOperation:(id<NSDraggingInfo>)sender
+{
+    NSPasteboard *pboard = [sender draggingPasteboard];
+    
+    if ( [[pboard types] containsObject:NSURLPboardType] ) {
+        NSURL *fileURL = [NSURL URLFromPasteboard:pboard];
+        return [_document loadStateFile:fileURL.fileSystemRepresentation];
+    }
+
+    return false;
+}
+
 @end

Core/gb.c

@@ -19,12 +19,6 @@
 #endif
 
 
-static inline uint32_t state_magic(void)
-{
-    if (sizeof(bool) == 1) return 'SAME';
-    return 'S4ME';
-}
-
 void GB_attributed_logv(GB_gameboy_t *gb, GB_log_attributes attributes, const char *fmt, va_list args)
 {
     char *string = NULL;

Core/save_state.c

@@ -1170,3 +1170,36 @@ int GB_load_state_from_buffer(GB_gameboy_t *gb, const uint8_t *buffer, size_t le
     
     return load_state_internal(gb, &file);
 }
+
+
+bool GB_is_stave_state(const char *path)
+{
+    bool ret = false;
+    FILE *f = fopen(path, "rb");
+    if (!f) return false;
+    uint32_t magic = 0;
+    fread(&magic, sizeof(magic), 1, f);
+    if (magic == state_magic()) {
+        ret = true;
+        goto exit;
+    }
+    
+    // Legacy corrupted Windows save state
+    if (magic == 0) {
+        fread(&magic, sizeof(magic), 1, f);
+        if (magic == state_magic()) {
+            ret = true;
+            goto exit;
+        }
+    }
+    
+    fseek(f, -sizeof(magic), SEEK_END);
+    fread(&magic, sizeof(magic), 1, f);
+    if (magic == BE32('BESS')) {
+        ret = true;
+    }
+    
+exit:
+    fclose(f);
+    return ret;
+}

Core/save_state.h

@@ -27,8 +27,14 @@ void GB_save_state_to_buffer(GB_gameboy_t *gb, uint8_t *buffer);
 
 int GB_load_state(GB_gameboy_t *gb, const char *path);
 int GB_load_state_from_buffer(GB_gameboy_t *gb, const uint8_t *buffer, size_t length);
-
+bool GB_is_stave_state(const char *path);
 #ifdef GB_INTERNAL
+static inline uint32_t state_magic(void)
+{
+    if (sizeof(bool) == 1) return 'SAME';
+    return 'S4ME';
+}
+
 /* For internal in-memory save states (rewind, debugger) that do not need BESS */
 size_t GB_get_save_state_size_no_bess(GB_gameboy_t *gb);
 void GB_save_state_to_buffer_no_bess(GB_gameboy_t *gb, uint8_t *buffer);

SDL/gui.c

@@ -18,6 +18,7 @@ SDL_Texture *texture = NULL;
 SDL_PixelFormat *pixel_format = NULL;
 enum pending_command pending_command;
 unsigned command_parameter;
+char *dropped_state_file = NULL;
 
 #ifdef __APPLE__
 #define MODIFIER_NAME " " CMD_STRING
@@ -1300,9 +1301,15 @@ void run_gui(bool is_running)
                 break;
             }
             case SDL_DROPFILE: {
-                set_filename(event.drop.file, SDL_free);
-                pending_command = GB_SDL_NEW_FILE_COMMAND;
-                return;
+                if (GB_is_stave_state(event.drop.file)) {
+                    dropped_state_file = event.drop.file;
+                    pending_command = GB_SDL_LOAD_STATE_FROM_FILE_COMMAND;
+                }
+                else {
+                    set_filename(event.drop.file, SDL_free);
+                    pending_command = GB_SDL_NEW_FILE_COMMAND;
+                    return;
+                }
             }
             case SDL_JOYBUTTONDOWN:
             {

SDL/gui.h

@@ -39,12 +39,14 @@ enum pending_command {
     GB_SDL_RESET_COMMAND,
     GB_SDL_NEW_FILE_COMMAND,
     GB_SDL_QUIT_COMMAND,
+    GB_SDL_LOAD_STATE_FROM_FILE_COMMAND,
 };
 
 #define GB_SDL_DEFAULT_SCALE_MAX 8
 
 extern enum pending_command pending_command;
 extern unsigned command_parameter;
+extern char *dropped_state_file;
 
 typedef enum {
     JOYPAD_BUTTON_LEFT,

SDL/main.c

@@ -142,8 +142,14 @@ static void handle_events(GB_gameboy_t *gb)
                 break;
                 
             case SDL_DROPFILE: {
-                set_filename(event.drop.file, SDL_free);
-                pending_command = GB_SDL_NEW_FILE_COMMAND;
+                if (GB_is_stave_state(event.drop.file)) {
+                    dropped_state_file = event.drop.file;
+                    pending_command = GB_SDL_LOAD_STATE_FROM_FILE_COMMAND;
+                }
+                else {
+                    set_filename(event.drop.file, SDL_free);
+                    pending_command = GB_SDL_NEW_FILE_COMMAND;
+                }
                 break;
             }
                 
@@ -433,6 +439,13 @@ static bool handle_pending_command(void)
             end_capturing_logs(true, false);
             return false;
         }
+    
+        case GB_SDL_LOAD_STATE_FROM_FILE_COMMAND:
+            start_capturing_logs();
+            GB_load_state(&gb, dropped_state_file);
+            end_capturing_logs(true, false);
+            SDL_free(dropped_state_file);
+            return false;
             
         case GB_SDL_NO_COMMAND:
             return false;