Finishing BDeskbar implementation and fixing minor test issue.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@1169 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/interface/Deskbar.cpp

@@ -139,6 +139,38 @@ status_t BDeskbar::Expand(bool expand)
 //------------------------------------------------------------------------------
 status_t BDeskbar::GetItemInfo(int32 id, const char **name) const
 {
+	/* NOTE: Be's implementation returned B_BAD_VALUE if *name was NULL,
+	   not just if name was NULL.  This doesn't make much sense.  Be's
+	   implementation means you cannot do the following:
+	   		
+	   		const char *buffer = NULL;
+	   		myDeskbar.GetItemInfo(id, &buffer);
+	   
+	   Instead, you are forced to write code that looks like:
+	   
+	   		char tmpBuf[10];
+	   		const char *buffer = tmpBuf;
+	   		myDeskbar.GetItemInfo(id, &buffer);
+	   		
+	   There are a couple of issues with this:
+	   	- Be's implementation does not use the space pointed to in buffer.
+	   	  It cannot since it can't tell how big that space is and it won't
+	   	  know whether the item's name will fit without overflowing the
+	   	  buffer.
+	   	- Worse, if the code looked like:
+	   	
+	   		const char *buffer = new char[5];
+	   		myDeskbar.GetItemInfo(id, &buffer);
+	      
+	       The code will result in a memory leak.  The problem here is that
+	       what buffer points to is changed by GetItemInfo().  If buffer
+	       points to dynamically allocated memory, there is a good chance
+	       the result is a memory leak.
+	   
+	   The OpenBeOS implementation will allow *name to point to NULL or
+	   non-NULL.  If anything, we should consider forcing *name to point to
+	   NULL for safety.
+	 */
 	if (name == NULL) {
 		return(B_BAD_VALUE);
 	}

src/kits/interface/interface.src

@@ -5,6 +5,7 @@ INTERFACE_KIT_SOURCE =
 	Button.cpp
 	CheckBox.cpp
 	Control.cpp
+	Deskbar.cpp
 	PictureButton.cpp
 	Point.cpp
 	RadioButton.cpp

src/tests/kits/interface/bdeskbar/DeskbarGetItemTest.cpp

@@ -1,5 +1,5 @@
 /*
-	$Id: DeskbarGetItemTest.cpp,v 1.2 2002/09/13 03:51:09 jrand Exp $
+	$Id: DeskbarGetItemTest.cpp,v 1.3 2002/09/25 03:24:17 jrand Exp $
 	
 	This file implements tests for the following use cases of BDeskbar:
 	  - Count Items
@@ -68,8 +68,17 @@
 		if (myDeskbar.HasItem(id)) {
 			itemCount--;
 			
+			/* In Be's implementation, if the char * points to NULL, it
+			   returns B_BAD_VALUE.  However, no matter what it points to
+			   before you start, it is changed by the call to GetItemInfo().
+			   So, if it points to allocated memory, there is a good chance
+			   for a leak.  I would argue that Be should return B_BAD_VALUE
+			   if it points to non-NULL.  The OpenBeOS implementation does
+			   not return B_BAD_VALUE in this case so this assert would fail
+			   from OpenBeOS.  However, this is considered to be an acceptable
+			   deviation from Be's implementation.
 			name = NULL;
-			assert(myDeskbar.GetItemInfo(id, &name) == B_BAD_VALUE);
+			assert(myDeskbar.GetItemInfo(id, &name) == B_BAD_VALUE); */
 			
 			name = buffer;
 			assert(myDeskbar.GetItemInfo(id, &name) == B_OK);