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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/shell_dialogs/base_shell_dialog_win.h"
#include <algorithm>
#include "base/no_destructor.h"
#include "base/task/single_thread_task_runner.h"
#include "base/task/thread_pool.h"
#include "base/win/scoped_com_initializer.h"
namespace ui {
namespace {
// Creates a SingleThreadTaskRunner to run a shell dialog on. Each dialog
// requires its own dedicated single-threaded sequence 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.
scoped_refptr<base::SingleThreadTaskRunner> CreateDialogTaskRunner() {
return base::ThreadPool::CreateCOMSTATaskRunner(
{base::TaskPriority::USER_BLOCKING,
base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN, base::MayBlock()},
base::SingleThreadTaskRunnerThreadMode::DEDICATED);
}
// Enables the window |owner|. Can only be run from the UI thread.
void SetOwnerEnabled(HWND owner, bool enabled) {
if (IsWindow(owner))
EnableWindow(owner, enabled);
}
} // namespace
BaseShellDialogImpl::RunState::RunState() = default;
BaseShellDialogImpl::RunState::~RunState() = default;
// static
int BaseShellDialogImpl::instance_count_ = 0;
BaseShellDialogImpl::BaseShellDialogImpl() {
++instance_count_;
}
BaseShellDialogImpl::~BaseShellDialogImpl() {
// All runs should be complete by the time this is called!
if (--instance_count_ == 0)
DCHECK(GetOwners().empty());
}
// static
BaseShellDialogImpl::Owners& BaseShellDialogImpl::GetOwners() {
static base::NoDestructor<BaseShellDialogImpl::Owners> owners;
return *owners;
}
// static
void BaseShellDialogImpl::DisableOwner(HWND owner) {
SetOwnerEnabled(owner, false);
}
std::unique_ptr<BaseShellDialogImpl::RunState> BaseShellDialogImpl::BeginRun(
HWND owner) {
// Cannot run a modal shell dialog if one is already running for this owner.
DCHECK(!IsRunningDialogForOwner(owner));
// The owner must be a top level window, otherwise we could end up with two
// entries in our map for the same top level window.
DCHECK(!owner || owner == GetAncestor(owner, GA_ROOT));
auto run_state = std::make_unique<RunState>();
run_state->dialog_task_runner = CreateDialogTaskRunner();
run_state->owner = owner;
if (owner) {
GetOwners().insert(owner);
DisableOwner(owner);
}
return run_state;
}
void BaseShellDialogImpl::EndRun(std::unique_ptr<RunState> run_state) {
if (run_state->owner) {
DCHECK(IsRunningDialogForOwner(run_state->owner));
SetOwnerEnabled(run_state->owner, true);
DCHECK(GetOwners().find(run_state->owner) != GetOwners().end());
GetOwners().erase(run_state->owner);
}
}
bool BaseShellDialogImpl::IsRunningDialogForOwner(HWND owner) const {
return (owner && GetOwners().find(owner) != GetOwners().end());
}
} // namespace ui
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