Skip to content

Commit

Permalink
Prevent crash on application shutdown in Windows PE
Browse files Browse the repository at this point in the history 
In environments like Windows PE, there is no shell or taskbar. That then
means that the TaskbarButtonCreated window message will never be
received.

Previously, the TaskbarThumbnails class would create the tab proxies and
destroy them, even if the TaskbarButtonCreated message wasn't received.
When the application was shutting down, that would then cause a crash,
as the DestroyTabProxy() method would attempt to use m_pTaskbarList,
which wouldn't have been set up.

To fix that, the TaskbarThumbnails class has been refactored so that the
tab proxies will only be created once the TaskbarButtonCreated message
has been received and the tab/application observers will only be added
at that point as well.

This issue was reported in #369.
  • Loading branch information
@derceg
derceg committed Dec 1, 2022
1 parent d7b14ef commit 6429b62
Show file tree
Hide file tree
Showing 2 changed files with 84 additions and 102 deletions.
180 changes: 80 additions & 100 deletions Explorer++/Explorer++/TaskbarThumbnails.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,9 +42,7 @@ TaskbarThumbnails::TaskbarThumbnails(CoreInterface *coreInterface, TabContainer
m_coreInterface(coreInterface),
m_tabContainer(tabContainer),
m_instance(instance),
m_bTaskbarInitialised(false),
m_enabled(config->showTaskbarThumbnails),
m_pTaskbarList(nullptr)
m_enabled(config->showTaskbarThumbnails)
{
Initialize();
}
Expand All @@ -65,20 +63,6 @@ void TaskbarThumbnails::Initialize()
/* Subclass the main window until the above message (TaskbarButtonCreated) is caught. */
SetWindowSubclass(m_coreInterface->GetMainWindow(), MainWndProcStub, 0,
reinterpret_cast<DWORD_PTR>(this));

m_tabContainer->tabCreatedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::CreateTabProxy, this));
m_tabContainer->tabNavigationCommittedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::OnNavigationCommitted, this));
m_tabContainer->tabNavigationCompletedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::OnNavigationCompleted, this));
m_tabContainer->tabSelectedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::OnTabSelectionChanged, this));
m_tabContainer->tabRemovedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::RemoveTabProxy, this));

m_connections.push_back(m_coreInterface->AddApplicationShuttingDownObserver(
std::bind_front(&TaskbarThumbnails::OnApplicationShuttingDown, this)));
}

LRESULT CALLBACK TaskbarThumbnails::MainWndProcStub(HWND hwnd, UINT uMsg, WPARAM wParam,
Expand All @@ -93,41 +77,63 @@ LRESULT CALLBACK TaskbarThumbnails::MainWndProcStub(HWND hwnd, UINT uMsg, WPARAM

LRESULT CALLBACK TaskbarThumbnails::MainWndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
// Note that this message won't be received in environments like Windows PE, where there is no
// shell/taskbar.
if (uMsg == m_uTaskbarButtonCreatedMessage)
{
if (m_pTaskbarList != nullptr)
{
m_pTaskbarList->Release();
}
OnTaskbarButtonCreated();
RemoveWindowSubclass(hwnd, MainWndProcStub, 0);
return 0;
}

CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_INPROC_SERVER,
IID_PPV_ARGS(&m_pTaskbarList));
m_pTaskbarList->HrInit();
return DefSubclassProc(hwnd, uMsg, wParam, lParam);
}

m_bTaskbarInitialised = TRUE;
void TaskbarThumbnails::OnTaskbarButtonCreated()
{
HRESULT hr = CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_INPROC_SERVER,
IID_PPV_ARGS(&m_taskbarList));

/* Add each of the jump list tasks. */
SetupJumplistTasks();
if (FAILED(hr))
{
return;
}

/* Register each of the tabs. */
for (auto itr = m_TabProxyList.begin(); itr != m_TabProxyList.end(); itr++)
{
const Tab &tab = m_tabContainer->GetTab(itr->iTabId);
hr = m_taskbarList->HrInit();

BOOL bActive = m_tabContainer->IsTabSelected(tab);
if (FAILED(hr))
{
return;
}

RegisterTab(itr->hProxy, EMPTY_STRING, bActive);
SetupJumplistTasks();

UpdateTaskbarThumbnailTitle(tab);
SetTabProxyIcon(tab);
}
for (const auto &tab : m_tabContainer->GetAllTabsInOrder())
{
CreateTabProxy(tab.get().GetId(), m_tabContainer->IsTabSelected(tab.get()));
}

RemoveWindowSubclass(hwnd, MainWndProcStub, 0);
SetUpObservers();
}

return 0;
}
// Sets up the observers required to manage the taskbar thumbnails (e.g. to keep the thumbnails in
// sync with the list of tabs). These observers are only needed if the taskbar thumbnails are
// enabled and the functionality is available.
void TaskbarThumbnails::SetUpObservers()
{
m_connections.push_back(m_tabContainer->tabCreatedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::CreateTabProxy, this)));
m_connections.push_back(m_tabContainer->tabNavigationCommittedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::OnNavigationCommitted, this)));
m_connections.push_back(m_tabContainer->tabNavigationCompletedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::OnNavigationCompleted, this)));
m_connections.push_back(m_tabContainer->tabSelectedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::OnTabSelectionChanged, this)));
m_connections.push_back(m_tabContainer->tabRemovedSignal.AddObserver(
std::bind_front(&TaskbarThumbnails::RemoveTabProxy, this)));

return DefSubclassProc(hwnd, uMsg, wParam, lParam);
m_connections.push_back(m_coreInterface->AddApplicationShuttingDownObserver(
std::bind_front(&TaskbarThumbnails::OnApplicationShuttingDown, this)));
}

void TaskbarThumbnails::SetupJumplistTasks()
Expand Down Expand Up @@ -180,64 +186,48 @@ thumbnail preview for the tab.
*/
void TaskbarThumbnails::CreateTabProxy(int iTabId, BOOL bSwitchToNewTab)
{
HWND hTabProxy;
TabProxyInfo tpi;
static int iCount = 0;
TCHAR szClassName[512];
ATOM aRet;
BOOL bValue = TRUE;
StringCchPrintf(szClassName, SIZEOF_ARRAY(szClassName), _T("Explorer++TabProxy%d"), iCount++);

if (!m_enabled)
ATOM aRet = RegisterTabProxyClass(szClassName);

if (aRet == 0)
{
return;
}

static int iCount = 0;

StringCchPrintf(szClassName, SIZEOF_ARRAY(szClassName), _T("Explorer++TabProxy%d"), iCount++);
TabProxy *ptp = new TabProxy();
ptp->taskbarThumbnails = this;
ptp->iTabId = iTabId;

aRet = RegisterTabProxyClass(szClassName);
HWND hTabProxy = CreateWindow(szClassName, EMPTY_STRING, WS_OVERLAPPEDWINDOW, 0, 0, 0, 0,
nullptr, nullptr, GetModuleHandle(nullptr), (LPVOID) ptp);

if (aRet != 0)
if (!hTabProxy)
{
TabProxy *ptp = new TabProxy();
ptp->taskbarThumbnails = this;
ptp->iTabId = iTabId;

hTabProxy = CreateWindow(szClassName, EMPTY_STRING, WS_OVERLAPPEDWINDOW, 0, 0, 0, 0,
nullptr, nullptr, GetModuleHandle(nullptr), (LPVOID) ptp);

if (hTabProxy != nullptr)
{
DwmSetWindowAttribute(hTabProxy, DWMWA_FORCE_ICONIC_REPRESENTATION, &bValue,
sizeof(BOOL));

DwmSetWindowAttribute(hTabProxy, DWMWA_HAS_ICONIC_BITMAP, &bValue, sizeof(BOOL));
return;
}

if (m_bTaskbarInitialised)
{
RegisterTab(hTabProxy, EMPTY_STRING, bSwitchToNewTab);
}
BOOL bValue = TRUE;
DwmSetWindowAttribute(hTabProxy, DWMWA_FORCE_ICONIC_REPRESENTATION, &bValue, sizeof(BOOL));
DwmSetWindowAttribute(hTabProxy, DWMWA_HAS_ICONIC_BITMAP, &bValue, sizeof(BOOL));
RegisterTab(hTabProxy, EMPTY_STRING, bSwitchToNewTab);

tpi.hProxy = hTabProxy;
tpi.iTabId = iTabId;
tpi.atomClass = aRet;
TabProxyInfo tpi;
tpi.hProxy = hTabProxy;
tpi.iTabId = iTabId;
tpi.atomClass = aRet;

m_TabProxyList.push_back(std::move(tpi));
m_TabProxyList.push_back(std::move(tpi));

const Tab &tab = m_tabContainer->GetTab(iTabId);
SetTabProxyIcon(tab);
UpdateTaskbarThumbnailTitle(tab);
}
}
const Tab &tab = m_tabContainer->GetTab(iTabId);
SetTabProxyIcon(tab);
UpdateTaskbarThumbnailTitle(tab);
}

void TaskbarThumbnails::RemoveTabProxy(int iTabId)
{
if (!m_bTaskbarInitialised)
{
return;
}

auto tabProxy = std::find_if(m_TabProxyList.begin(), m_TabProxyList.end(),
[iTabId](const TabProxyInfo &currentTabProxy)
{
Expand All @@ -257,7 +247,7 @@ void TaskbarThumbnails::RemoveTabProxy(int iTabId)

void TaskbarThumbnails::DestroyTabProxy(TabProxyInfo &tabProxy)
{
m_pTaskbarList->UnregisterTab(tabProxy.hProxy);
m_taskbarList->UnregisterTab(tabProxy.hProxy);

auto *ptp = reinterpret_cast<TabProxy *>(GetWindowLongPtr(tabProxy.hProxy, GWLP_USERDATA));
DestroyWindow(tabProxy.hProxy);
Expand All @@ -283,14 +273,14 @@ void TaskbarThumbnails::RegisterTab(HWND hTabProxy, const TCHAR *szDisplayName,
{
/* Register and insert the tab into the current list of
taskbar thumbnails. */
m_pTaskbarList->RegisterTab(hTabProxy, m_coreInterface->GetMainWindow());
m_pTaskbarList->SetTabOrder(hTabProxy, nullptr);
m_taskbarList->RegisterTab(hTabProxy, m_coreInterface->GetMainWindow());
m_taskbarList->SetTabOrder(hTabProxy, nullptr);

m_pTaskbarList->SetThumbnailTooltip(hTabProxy, szDisplayName);
m_taskbarList->SetThumbnailTooltip(hTabProxy, szDisplayName);

if (bTabActive)
{
m_pTaskbarList->SetTabActive(hTabProxy, m_coreInterface->GetMainWindow(), 0);
m_taskbarList->SetTabActive(hTabProxy, m_coreInterface->GetMainWindow(), 0);
}
}

Expand Down Expand Up @@ -601,11 +591,6 @@ wil::unique_hbitmap TaskbarThumbnails::GetTabLivePreviewBitmap(const Tab &tab)

void TaskbarThumbnails::OnTabSelectionChanged(const Tab &tab)
{
if (!m_bTaskbarInitialised)
{
return;
}

for (const TabProxyInfo &tabProxyInfo : m_TabProxyList)
{
if (tabProxyInfo.iTabId == tab.GetId())
Expand All @@ -618,7 +603,7 @@ void TaskbarThumbnails::OnTabSelectionChanged(const Tab &tab)
tell the taskbar to reposition it. */
if (index == (nTabs - 1))
{
m_pTaskbarList->SetTabOrder(tabProxyInfo.hProxy, nullptr);
m_taskbarList->SetTabOrder(tabProxyInfo.hProxy, nullptr);
}
else
{
Expand All @@ -628,13 +613,13 @@ void TaskbarThumbnails::OnTabSelectionChanged(const Tab &tab)
{
if (tabProxyInfoNext.iTabId == nextTab.GetId())
{
m_pTaskbarList->SetTabOrder(tabProxyInfo.hProxy, tabProxyInfoNext.hProxy);
m_taskbarList->SetTabOrder(tabProxyInfo.hProxy, tabProxyInfoNext.hProxy);
break;
}
}
}

m_pTaskbarList->SetTabActive(tabProxyInfo.hProxy, m_coreInterface->GetMainWindow(), 0);
m_taskbarList->SetTabActive(tabProxyInfo.hProxy, m_coreInterface->GetMainWindow(), 0);
break;
}
}
Expand All @@ -658,17 +643,12 @@ void TaskbarThumbnails::OnNavigationCompleted(const Tab &tab)

void TaskbarThumbnails::UpdateTaskbarThumbnailTitle(const Tab &tab)
{
if (!m_bTaskbarInitialised)
{
return;
}

for (const TabProxyInfo &tabProxyInfo : m_TabProxyList)
{
if (tabProxyInfo.iTabId == tab.GetId())
{
SetWindowText(tabProxyInfo.hProxy, tab.GetName().c_str());
m_pTaskbarList->SetThumbnailTooltip(tabProxyInfo.hProxy, tab.GetName().c_str());
m_taskbarList->SetThumbnailTooltip(tabProxyInfo.hProxy, tab.GetName().c_str());
break;
}
}
Expand Down
6 changes: 4 additions & 2 deletions Explorer++/Explorer++/TaskbarThumbnails.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
#include "Tab.h"
#include "../Helper/Macros.h"
#include <boost/signals2.hpp>
#include <wil/com.h>
#include <wil/resource.h>

struct Config;
Expand Down Expand Up @@ -42,6 +43,8 @@ class TaskbarThumbnails
LRESULT CALLBACK TabProxyWndProc(HWND hwnd, UINT Msg, WPARAM wParam, LPARAM lParam, int iTabId);

void Initialize();
void OnTaskbarButtonCreated();
void SetUpObservers();
void SetupJumplistTasks();
ATOM RegisterTabProxyClass(const TCHAR *szClassName);
void CreateTabProxy(int iTabId, BOOL bSwitchToNewTab);
Expand All @@ -64,9 +67,8 @@ class TaskbarThumbnails
HINSTANCE m_instance;
std::vector<boost::signals2::scoped_connection> m_connections;

ITaskbarList4 *m_pTaskbarList;
wil::com_ptr_nothrow<ITaskbarList4> m_taskbarList;
std::list<TabProxyInfo> m_TabProxyList;
UINT m_uTaskbarButtonCreatedMessage;
BOOL m_bTaskbarInitialised;
BOOL m_enabled;
};

0 comments on commit 6429b62

Please sign in to comment.