Added SDL_DROPBEGIN and SDL_DROPCOMPLETE events, plus window IDs for drops.

This allows an app to know when a set of drops are coming in a grouping of
some sort (for example, a user selected multiple files and dropped them all
on the window with a single drag), and when that set is complete.

This also adds a window ID to the drop events, so the app can determine to
which window a given drop was delivered. For application-level drops (for
example, you launched an app by dropping a file on its icon), the window ID
will be zero.

src/video/SDL_sysvideo.h

@@ -95,6 +95,7 @@ struct SDL_Window
 
     SDL_bool is_hiding;
     SDL_bool is_destroying;
+    SDL_bool is_dropping;       /* drag/drop in progress, expecting SDL_SendDropComplete(). */
 
     SDL_WindowShaper *shaper;
 

src/video/cocoa/SDL_cocoaevents.m

@@ -176,7 +176,7 @@
 
 - (BOOL)application:(NSApplication *)theApplication openFile:(NSString *)filename
 {
-    return (BOOL)SDL_SendDropFile([filename UTF8String]);
+    return (BOOL)SDL_SendDropFile(NULL, [filename UTF8String]) && SDL_SendDropComplete(NULL);
 }
 @end
 

src/video/cocoa/SDL_cocoawindow.m

@@ -116,9 +116,12 @@
 - (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
 { @autoreleasepool
 {
+    SDL_VideoDevice *_this = SDL_GetVideoDevice();
     NSPasteboard *pasteboard = [sender draggingPasteboard];
     NSArray *types = [NSArray arrayWithObject:NSFilenamesPboardType];
     NSString *desiredType = [pasteboard availableTypeFromArray:types];
+    SDL_Window *sdlwindow = nil;
+
     if (desiredType == nil) {
         return NO;  /* can't accept anything that's being dropped here. */
     }
@@ -157,11 +160,22 @@
             }
         }
 
-        if (!SDL_SendDropFile([[fileURL path] UTF8String])) {
+        /* !!! FIXME: is there a better way to do this? */
+        if (_this) {
+            for (sdlwindow = _this->windows; sdlwindow; sdlwindow = sdlwindow->next) {
+                NSWindow *nswindow = ((SDL_WindowData *) sdlwindow->driverdata)->nswindow;
+                if (nswindow == self) {
+                    break;
+                }
+            }
+        }
+
+        if (!SDL_SendDropFile(sdlwindow, [[fileURL path] UTF8String])) {
             return NO;
         }
     }
 
+    SDL_SendDropComplete(sdlwindow);
     return YES;
 }}
 

src/video/windows/SDL_windowsevents.c

@@ -907,12 +907,13 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
                 if (buffer) {
                     if (DragQueryFile(drop, i, buffer, size)) {
                         char *file = WIN_StringToUTF8(buffer);
-                        SDL_SendDropFile(file);
+                        SDL_SendDropFile(data->window, file);
                         SDL_free(file);
                     }
                     SDL_stack_free(buffer);
                 }
             }
+            SDL_SendDropComplete(data->window);
             DragFinish(drop);
             return 0;
         }

src/video/x11/SDL_x11events.c

@@ -1230,17 +1230,17 @@ X11_DispatchEvent(_THIS)
                     char *token = strtok((char *) p.data, "\r\n");
                     while (token != NULL) {
                         if (SDL_strcmp("text/plain", name)==0) {
-                            SDL_SendDropText(token);
+                            SDL_SendDropText(data->window, token);
                         } else if (SDL_strcmp("text/uri-list", name)==0) {
                             char *fn = X11_URIToLocal(token);
                             if (fn) {
-                                SDL_SendDropFile(fn);
+                                SDL_SendDropFile(data->window, fn);
                             }
                         }
                         token = strtok(NULL, "\r\n");
                     }
+                    SDL_SendDropComplete(data->window);
                 }
-
                 X11_XFree(p.data);
 
                 /* send reply */