app_server: some missing std::nothrow and error checks.

I had app_server crash on me because of an uncaught allocation
exception. I don't know if this will fix it but it's better to try to
survive even if it may result in some UI glitches.

Change-Id: I09dd2a7e6ff63d52f51389d7418d1a1d1810af00
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1720
Reviewed-by: waddlesplash <waddlesplash@gmail.com>

src/servers/app/drawing/DrawingEngine.cpp

@@ -428,7 +428,7 @@ struct node {
 	void init(const BRect& r, int32 maxPointers)
 	{
 		rect = r;
-		pointers = new node*[maxPointers];
+		pointers = new(std::nothrow) node*[maxPointers];
 		in_degree = 0;
 		next_pointer = 0;
 	}
@@ -490,6 +490,8 @@ DrawingEngine::CopyRegion(/*const*/ BRegion* region, int32 xOffset,
 	BStackOrHeapArray<node, 64> nodes(count);
 	for (int32 i= 0; i < count; i++) {
 		nodes[i].init(region->RectAt(i), count);
+		if (nodes[i].pointers == NULL)
+			return;
 	}
 
 	for (int32 i = 0; i < count; i++) {
@@ -551,8 +553,11 @@ DrawingEngine::CopyRegion(/*const*/ BRegion* region, int32 xOffset,
 	clipping_rect* sortedRectList = NULL;
 	int32 nextSortedIndex = 0;
 
-	if (fAvailableHWAccleration & HW_ACC_COPY_REGION)
-		sortedRectList = new clipping_rect[count];
+	if (fAvailableHWAccleration & HW_ACC_COPY_REGION) {
+		sortedRectList = new(std::nothrow) clipping_rect[count];
+		if (sortedRectList == NULL)
+			return;
+	}
 
 	while (!inDegreeZeroNodes.empty()) {
 		node* n = inDegreeZeroNodes.top();

src/servers/app/drawing/HWInterface.cpp

@@ -586,8 +586,10 @@ HWInterface::_DrawCursor(IntRect area) const
 		// that has the cursor blended on top of it
 
 		// blending buffer
-		uint8* buffer = new uint8[width * height * 4];
+		uint8* buffer = new(std::nothrow) uint8[width * height * 4];
 			// TODO: cache this buffer
+		if (buffer == NULL)
+			return;
 
 		// offset into back buffer
 		uint8* src = (uint8*)backBuffer->Bits();
@@ -1085,6 +1087,10 @@ HWInterface::_AdoptDragBitmap(const ServerBitmap* bitmap, const BPoint& offset)
 		BRect cursorBounds = fCursorAndDragBitmap->Bounds();
 		fCursorAreaBackup = new buffer_clip(cursorBounds.IntegerWidth() + 1,
 			cursorBounds.IntegerHeight() + 1);
+		if (fCursorAreaBackup->buffer == NULL) {
+			delete fCursorAreaBackup;
+			fCursorAreaBackup = NULL;
+		}
 	}
  	_DrawCursor(_CursorFrame());
 }

src/servers/app/drawing/HWInterface.h

@@ -18,6 +18,8 @@
 
 #include <video_overlay.h>
 
+#include <new>
+
 #include "IntRect.h"
 #include "MultiLocker.h"
 #include "ServerCursor.h"
@@ -224,7 +226,7 @@ protected:
 				{
 					bpr = width * 4;
 					if (bpr > 0 && height > 0)
-						buffer = new uint8[bpr * height];
+						buffer = new(std::nothrow) uint8[bpr * height];
 					else
 						buffer = NULL;
 					left = 0;