Mac: Better mouse-grab if you define SDL_MAC_NO_SANDBOX.

This uses a better mouse grab if you define SDL_MAC_NO_SANDBOX. This
mouse grab uses CGEventTapCreate, which you cannot access if you have
sandboxing enabled.

src/video/cocoa/SDL_cocoamouse.h

@@ -33,6 +33,7 @@ extern void Cocoa_QuitMouse(_THIS);
 typedef struct {
     int deltaXOffset;
     int deltaYOffset;
+    void *tapdata;
 } SDL_MouseData;
 
 @interface NSCursor (InvisibleCursor)

src/video/cocoa/SDL_cocoamouse.m

@@ -25,6 +25,7 @@
 #include "SDL_assert.h"
 #include "SDL_events.h"
 #include "SDL_cocoamouse.h"
+#include "SDL_cocoamousetap.h"
 
 #include "../../events/SDL_mouse_c.h"
 
@@ -94,6 +95,8 @@ Cocoa_CreateCursor(SDL_Surface * surface, int hot_x, int hot_y)
         cursor = SDL_calloc(1, sizeof(*cursor));
         if (cursor) {
             cursor->driverdata = nscursor;
+        } else {
+            [nscursor release];
         }
     }
 
@@ -266,6 +269,8 @@ Cocoa_InitMouse(_THIS)
     mouse->SetRelativeMouseMode = Cocoa_SetRelativeMouseMode;
 
     SDL_SetDefaultCursor(Cocoa_CreateDefaultCursor());
+
+    Cocoa_InitMouseEventTap(mouse->driverdata);
 }
 
 void
@@ -313,6 +318,10 @@ Cocoa_QuitMouse(_THIS)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
     if (mouse) {
+        if (mouse->driverdata) {
+            Cocoa_QuitMouseEventTap(((SDL_MouseData*)mouse->driverdata));
+        }
+
         SDL_free(mouse->driverdata);
     }
 }

src/video/cocoa/SDL_cocoamousetap.h

@@ -0,0 +1,33 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#ifndef _SDL_cocoamousetap_h
+#define _SDL_cocoamousetap_h
+
+#include "SDL_cocoamouse.h"
+
+extern void Cocoa_InitMouseEventTap(SDL_MouseData *driverdata);
+extern void Cocoa_QuitMouseEventTap(SDL_MouseData *driverdata);
+
+#endif /* _SDL_cocoamousetap_h */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/video/cocoa/SDL_cocoamousetap.m

@@ -0,0 +1,252 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+#if SDL_VIDEO_DRIVER_COCOA
+
+#define SDL_MAC_NO_SANDBOX 1
+
+#include "SDL_cocoamousetap.h"
+
+/* Event taps are forbidden in the Mac App Store, so we can only enable this
+ * code if your app doesn't need to ship through the app store.
+ * This code makes it so that a grabbed cursor cannot "leak" a mouse click
+ * past the edge of the window if moving the cursor too fast.
+ */
+#if SDL_MAC_NO_SANDBOX
+
+#include "SDL_keyboard.h"
+#include "SDL_thread.h"
+#include "SDL_cocoavideo.h"
+
+#include "../../events/SDL_mouse_c.h"
+
+typedef struct {
+    CFMachPortRef tap;
+    CFRunLoopRef runloop;
+    CFRunLoopSourceRef runloopSource;
+    SDL_Thread *thread;
+    SDL_sem *runloopStartedSemaphore;
+} SDL_MouseEventTapData;
+
+static const CGEventMask movementEventsMask =
+      CGEventMaskBit(kCGEventLeftMouseDragged)
+    | CGEventMaskBit(kCGEventRightMouseDragged)
+    | CGEventMaskBit(kCGEventMouseMoved);
+
+static const CGEventMask allGrabbedEventsMask =
+      CGEventMaskBit(kCGEventLeftMouseDown)    | CGEventMaskBit(kCGEventLeftMouseUp)
+    | CGEventMaskBit(kCGEventRightMouseDown)   | CGEventMaskBit(kCGEventRightMouseUp)
+    | CGEventMaskBit(kCGEventOtherMouseDown)   | CGEventMaskBit(kCGEventOtherMouseUp)
+    | CGEventMaskBit(kCGEventLeftMouseDragged) | CGEventMaskBit(kCGEventRightMouseDragged)
+    | CGEventMaskBit(kCGEventMouseMoved);
+
+static CGEventRef
+Cocoa_MouseTapCallback(CGEventTapProxy proxy, CGEventType type, CGEventRef event, void *refcon)
+{
+    SDL_MouseData *driverdata = (SDL_MouseData*)refcon;
+    SDL_Mouse *mouse = SDL_GetMouse();
+    SDL_Window *window = SDL_GetKeyboardFocus();
+    NSRect windowRect;
+    CGPoint eventLocation;
+
+    switch (type)
+    {
+        case kCGEventTapDisabledByTimeout:
+        case kCGEventTapDisabledByUserInput:
+            {
+                CGEventTapEnable(((SDL_MouseEventTapData*)(driverdata->tapdata))->tap, true);
+                return NULL;
+            }
+        default:
+            break;
+    }
+
+
+    if (!window || !mouse) {
+        return event;
+    }
+
+    if (mouse->relative_mode) {
+        return event;
+    }
+
+    if (!(window->flags & SDL_WINDOW_INPUT_GRABBED)) {
+        return event;
+    }
+
+    /* This is the same coordinate system as Cocoa uses. */
+    eventLocation = CGEventGetUnflippedLocation(event);
+    windowRect = [((SDL_WindowData *) window->driverdata)->nswindow frame];
+
+    if (!NSPointInRect(NSPointFromCGPoint(eventLocation), windowRect)) {
+
+        /* This is in CGs global screenspace coordinate system, which has a
+         * flipped Y.
+         */
+        CGPoint newLocation = CGEventGetLocation(event);
+
+        if (eventLocation.x < NSMinX(windowRect)) {
+            newLocation.x = NSMinX(windowRect);
+        } else if (eventLocation.x >= NSMaxX(windowRect)) {
+            newLocation.x = NSMaxX(windowRect) - 1.0;
+        }
+
+        if (eventLocation.y < NSMinY(windowRect)) {
+            newLocation.y -= (NSMinY(windowRect) - eventLocation.y + 1);
+        } else if (eventLocation.y >= NSMaxY(windowRect)) {
+            newLocation.y += (eventLocation.y - NSMaxY(windowRect) + 1);
+        }
+
+        CGSetLocalEventsSuppressionInterval(0);
+        CGWarpMouseCursorPosition(newLocation);
+        CGSetLocalEventsSuppressionInterval(0.25);
+
+        if ((CGEventMaskBit(type) & movementEventsMask) == 0) {
+            /* For click events, we just constrain the event to the window, so
+             * no other app receives the click event. We can't due the same to
+             * movement events, since they mean that our warp cursor above
+             * behaves strangely.
+             */
+            CGEventSetLocation(event, newLocation);
+        }
+    }
+
+    return event;
+}
+
+static int
+Cocoa_MouseTapThread(void *data)
+{
+    SDL_MouseEventTapData *tapdata = (SDL_MouseEventTapData*)data;
+
+    /* Create a tap. */
+    CFMachPortRef eventTap = CGEventTapCreate(kCGSessionEventTap, kCGHeadInsertEventTap,
+                                              kCGEventTapOptionDefault, allGrabbedEventsMask,
+                                              &Cocoa_MouseTapCallback, tapdata);
+    if (eventTap) {
+        /* Try to create a runloop source we can schedule. */
+        CFRunLoopSourceRef runloopSource = CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventTap, 0);
+        if  (runloopSource) {
+            tapdata->tap = eventTap;
+            tapdata->runloopSource = runloopSource;
+        } else {
+            CFRelease(eventTap);
+            SDL_SemPost(tapdata->runloopStartedSemaphore);
+            /* TODO: Both here and in the return below, set some state in
+             * tapdata to indicate that initialization failed, which we should
+             * check in InitMouseEventTap, after we move the semaphore check
+             * from Quit to Init.
+             */
+            return 1;
+        }
+    } else {
+        SDL_SemPost(tapdata->runloopStartedSemaphore);
+        return 1;
+    }
+
+    tapdata->runloop = CFRunLoopGetCurrent();
+    CFRunLoopAddSource(tapdata->runloop, tapdata->runloopSource, kCFRunLoopCommonModes);
+    CFRunLoopPerformBlock(tapdata->runloop, kCFRunLoopCommonModes, ^{
+        /* We signal this *after* the run loop has started, indicating it's safe to CFRunLoopStop it. */
+        SDL_SemPost(tapdata->runloopStartedSemaphore);
+    });
+
+    /* Run the event loop to handle events in the event tap. */
+    CFRunLoopRun();
+    /* Make sure this is signaled so that SDL_QuitMouseEventTap knows it can safely SDL_WaitThread for us. */
+    if (SDL_SemValue(tapdata->runloopStartedSemaphore) < 1) {
+        SDL_SemPost(tapdata->runloopStartedSemaphore);
+    }
+    CFRunLoopRemoveSource(tapdata->runloop, tapdata->runloopSource, kCFRunLoopCommonModes);
+
+    /* Clean up. */
+    CGEventTapEnable(tapdata->tap, false);
+    CFRelease(tapdata->runloopSource);
+    CFRelease(tapdata->tap);
+    tapdata->runloopSource = NULL;
+    tapdata->tap = NULL;
+
+    return 0;
+}
+
+void
+Cocoa_InitMouseEventTap(SDL_MouseData* driverdata)
+{
+    SDL_MouseEventTapData *tapdata;
+    driverdata->tapdata = SDL_calloc(1, sizeof(SDL_MouseEventTapData));
+    tapdata = (SDL_MouseEventTapData*)driverdata->tapdata;
+
+    tapdata->runloopStartedSemaphore = SDL_CreateSemaphore(0);
+    if (tapdata->runloopStartedSemaphore) {
+        tapdata->thread = SDL_CreateThread(&Cocoa_MouseTapThread, "Event Tap Loop", tapdata);
+        if (!tapdata->thread) {
+            SDL_DestroySemaphore(tapdata->runloopStartedSemaphore);
+        }
+    }
+
+    if (!tapdata->thread) {
+        SDL_free(driverdata->tapdata);
+        driverdata->tapdata = NULL;
+    }
+}
+
+void
+Cocoa_QuitMouseEventTap(SDL_MouseData *driverdata)
+{
+    SDL_MouseEventTapData *tapdata = (SDL_MouseEventTapData*)driverdata->tapdata;
+    int status;
+
+    /* Ensure that the runloop has been started first.
+     * TODO: Move this to InitMouseEventTap, check for error conditions that can
+     * happen in Cocoa_MouseTapThread, and fall back to the non-EventTap way of
+     * grabbing the mouse if it fails to Init.
+     */
+    status = SDL_SemWaitTimeout(tapdata->runloopStartedSemaphore, 5000);
+    if (status > -1) {
+        /* Then stop it, which will cause Cocoa_MouseTapThread to return. */
+        CFRunLoopStop(tapdata->runloop);
+        /* And then wait for Cocoa_MouseTapThread to finish cleaning up. It
+         * releases some of the pointers in tapdata. */
+        SDL_WaitThread(tapdata->thread, &status);
+    }
+
+    SDL_free(driverdata->tapdata);
+    driverdata->tapdata = NULL;
+}
+
+#else /* SDL_MAC_NO_SANDBOX */
+
+void
+Cocoa_InitMouseEventTap(SDL_MouseData *unused)
+{
+}
+
+void
+Cocoa_QuitMouseEventTap(SDL_MouseData *driverdata)
+{
+}
+
+#endif /* !SDL_MAC_NO_SANDBOX */
+
+#endif /* SDL_VIDEO_DRIVER_COCOA */
+
+/* vi: set ts=4 sw=4 expandtab: */

src/video/cocoa/SDL_cocoawindow.m

@@ -414,6 +414,11 @@ static __inline__ void ConvertNSRect(NSRect *r)
                 y = window->h - 1;
             }
 
+#if !SDL_MAC_NO_SANDBOX
+            /* When SDL_MAC_NO_SANDBOX is set, this is handled by
+             * SDL_cocoamousetap.m.
+             */
+
             cgpoint.x = window->x + x;
             cgpoint.y = window->y + y;
 
@@ -424,6 +429,7 @@ static __inline__ void ConvertNSRect(NSRect *r)
             CGSetLocalEventsSuppressionInterval(0.0);
             CGDisplayMoveCursorToPoint(kCGDirectMainDisplay, cgpoint);
             CGSetLocalEventsSuppressionInterval(0.25);
+#endif
         }
     }
     SDL_SendMouseMotion(window, 0, 0, x, y);