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// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <shlobj.h>
#include <set>
#include "ui/shell_dialogs/base_shell_dialog.h"
#include "ui/shell_dialogs/shell_dialogs_export.h"
namespace base {
class Thread;
namespace ui {
// A base class for all shell dialog implementations that handles showing a
// shell dialog modally on its own thread.
class SHELL_DIALOGS_EXPORT BaseShellDialogImpl {
virtual ~BaseShellDialogImpl();
// Represents a run of a dialog.
struct RunState {
// Owning HWND, may be null.
HWND owner;
// Thread dialog is run on.
base::Thread* dialog_thread;
// Called at the beginning of a modal dialog run. Disables the owner window
// and tracks it. Returns the message loop of the thread that the dialog will
// be run on.
RunState BeginRun(HWND owner);
// Cleans up after a dialog run. If the run_state has a valid HWND this makes
// sure that the window is enabled. This is essential because BeginRun
// aggressively guards against multiple modal dialogs per HWND. Must be called
// on the UI thread after the result of the dialog has been determined.
// In addition this deletes the Thread in RunState.
void EndRun(RunState run_state);
// Returns true if a modal shell dialog is currently active for the specified
// owner. Must be called on the UI thread.
bool IsRunningDialogForOwner(HWND owner) const;
// Disables the window |owner|. Can be run from either the ui or the dialog
// thread. Can be called on either the UI or the dialog thread. This function
// is called on the dialog thread after the modal Windows Common dialog
// functions return because Windows automatically re-enables the owning
// window when those functions return, but we don't actually want them to be
// re-enabled until the response of the dialog propagates back to the UI
// thread, so we disable the owner manually after the Common dialog function
// returns.
void DisableOwner(HWND owner);
typedef std::set<HWND> Owners;
// Creates a thread to run a shell dialog on. Each dialog requires its own
// thread otherwise in some situations where a singleton owns a single
// instance of this object we can have a situation where a modal dialog in
// one window blocks the appearance of a modal dialog in another.
static base::Thread* CreateDialogThread();
// Enables the window |owner_|. Can only be run from the ui thread.
void EnableOwner(HWND owner);
// A list of windows that currently own active shell dialogs for this
// instance. For example, if the DownloadManager owns an instance of this
// object and there are two browser windows open both with Save As dialog
// boxes active, this list will consist of the two browser windows' HWNDs.
// The derived class must call EndRun once the dialog is done showing to
// remove the owning HWND from this list.
// This object is static since it is maintained for all instances of this
// object - i.e. you can't have two file pickers open for the
// same owner, even though they might be represented by different instances
// of this object.
// This set only contains non-null HWNDs. NULL hwnds are not added to this
// list.
static Owners owners_;
static int instance_count_;
} // namespace ui