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/* There are several ways to open a new window in Mozilla: directly, using
   nsAppShellService; indirectly, using the Open method on an extant
   window, the OpenWindow method on the nsWindowWatcher service, and this
   WindowCreator. I think that's all of them, for petessake.  But
   the conditions under which each should be used are definite, if
   not clear, and there is no overlap.

   Basically, you should never use nsAppShellService. That's the basic
   method that all others boil down to, and it creates partially initialized
   windows. Trust the other means of opening windows to use nsAppShellService
   and then finish the new window's initialization. nsAppShellService is
   also strictly a Mozilla-only service; it's unavailable (or should be)
   to embedding apps. So it's not merely inadvisable but also illegal
   for any code that may execute in an embedding context to use that service.

   Unless you're writing window opening code yourself, you want to use
   the Open method on an extant window, or lacking one of those, the
   OpenWindow method on the nsWindowWatcher service. (The former calls
   through to the latter.) Both methods are equally at home in Mozilla
   and embedding contexts. They differentiate between which kind of window
   to open in different ways, depending on whether there is an extant
   window.

   Lacking an extant window, it's this object, the nsWindowCreator,
   that allows new window creation and properly distinguishes between
   Mozilla and embedding contexts. This source file contains the
   Mozilla version, which calls through to nsAppShellService.
*/

#include "nsCOMPtr.h"
#include "nsAppShellCIDs.h"
#include "nsWidgetsCID.h"
#include "nsWindowCreator.h"

#include "nsIAppShell.h"
#include "nsIAppShellService.h"
#include "nsIDocShellTreeItem.h"
#include "nsIInterfaceRequestor.h"
#include "nsIInterfaceRequestorUtils.h"
#include "nsIJSContextStack.h"
#include "nsIServiceManager.h"
#include "nsIXULWindow.h"
#include "nsIWebBrowserChrome.h"

static NS_DEFINE_CID(kAppShellServiceCID, NS_APPSHELL_SERVICE_CID);
static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);

nsWindowCreator::nsWindowCreator() {
  NS_INIT_REFCNT();
}

nsWindowCreator::~nsWindowCreator() {
}

NS_IMPL_ISUPPORTS1(nsWindowCreator, nsIWindowCreator)

NS_IMETHODIMP
nsWindowCreator::CreateChromeWindow(nsIWebBrowserChrome *aParent,
                                    PRUint32 aChromeFlags,
                                    nsIWebBrowserChrome **_retval)
{
  NS_ENSURE_ARG_POINTER(_retval);
  *_retval = 0;

  nsCOMPtr<nsIXULWindow> newWindow;

  if (aParent) {
    nsCOMPtr<nsIXULWindow> xulParent(do_GetInterface(aParent));
    NS_ASSERTION(xulParent, "window created using non-XUL parent. that's unexpected, but may work.");
    if (xulParent)
      xulParent->CreateNewWindow(aChromeFlags, getter_AddRefs(newWindow));
    // And if it fails, don't try again without a parent. It could fail
    // intentionally (bug 115969).
  } else { // try using basic methods:
    /* You really shouldn't be making dependent windows without a parent.
      But unparented modal (and therefore dependent) windows happen
      in our codebase, so we allow it after some bellyaching: */
    if (aChromeFlags & nsIWebBrowserChrome::CHROME_DEPENDENT)
      NS_WARNING("dependent window created without a parent");

    nsCOMPtr<nsIAppShellService> appShell(do_GetService(kAppShellServiceCID));
    if (!appShell)
      return NS_ERROR_FAILURE;
    
    appShell->CreateTopLevelWindow(0, 0, PR_FALSE, PR_FALSE,
      aChromeFlags, nsIAppShellService::SIZE_TO_CONTENT,
      nsIAppShellService::SIZE_TO_CONTENT, getter_AddRefs(newWindow));
  }

  // if anybody gave us anything to work with, use it
  nsCOMPtr<nsIInterfaceRequestor> thing(do_QueryInterface(newWindow));
  if (thing)
    thing->GetInterface(NS_GET_IID(nsIWebBrowserChrome), (void **) _retval);

  return *_retval ? NS_OK : NS_ERROR_FAILURE;
}