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more cleanup

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This commit is contained in:
Mike Griese 2021-08-25 08:25:20 -05:00
parent 354e4b00a3
commit 5c17603a94
1 changed files with 64 additions and 51 deletions
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115
src/cascadia/WindowsTerminal/ContentProcessMain.cpp
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@ -13,6 +13,69 @@ using namespace winrt::Windows::UI::Composition;
using namespace winrt::Windows::UI::Xaml::Hosting;
using namespace winrt::Windows::Foundation::Numerics;
// We keep a weak ref to our ContentProcess singleton here.
// Why?
//
// We need to always return the _same_ ContentProcess when someone comes to
// instantiate this class. So we want to track the single instance we make. We
// also want to track when the last outstanding reference to this object is
// removed. If we're keeping a strong ref, then the ref count will always be > 1
winrt::weak_ref<winrt::Microsoft::Terminal::Control::ContentProcess> g_weak{ nullptr };
wil::unique_event g_canExitThread;
struct ContentProcessFactory : implements<ContentProcessFactory, IClassFactory>
{
ContentProcessFactory(winrt::guid g) :
_guid{ g } {};
HRESULT __stdcall CreateInstance(IUnknown* outer, GUID const& iid, void** result) noexcept final
{
*result = nullptr;
if (outer)
{
return CLASS_E_NOAGGREGATION;
}
if (!g_weak)
{
// Instantiate the ContentProcess here
winrt::Microsoft::Terminal::Control::ContentProcess strong{};
// Now, create a weak ref to that ContentProcess object.
winrt::weak_ref<winrt::Microsoft::Terminal::Control::ContentProcess> weak{ strong };
// Stash away that weak ref for future callers.
g_weak = weak;
return strong.as(iid, result);
}
else
{
auto strong = g_weak.get();
// !! LOAD BEARING !! If you set this event in the _first_ branch
// here, when we first create the object, then there will be _no_
// referernces to the ContentProcess object for a small slice. We'll
// stash the ContentProcess in the weak_ptr, and return it, and at
// that moment, there will be 0 outstanding references, it'll dtor,
// and wei'll ExitProcess.
//
// Instead, set the event here, once there's already a reference
// outside of just the weak one we keep. Experimentation showed this
// waw always hit when creating the ContentProcess at least once.
g_canExitThread.SetEvent();
return strong.as(iid, result);
}
}
HRESULT __stdcall LockServer(BOOL) noexcept final
{
return S_OK;
}
private:
winrt::guid _guid;
};
static bool checkIfContentProcess(winrt::guid& contentProcessGuid, HANDLE& eventHandle)
{
std::vector<std::wstring> args;
@ -52,63 +115,13 @@ static bool checkIfContentProcess(winrt::guid& contentProcessGuid, HANDLE& event
return false;
}
winrt::weak_ref<winrt::Microsoft::Terminal::Control::ContentProcess> g_weak{ nullptr };
wil::unique_event g_canExitThread;
struct HostClassFactory : implements<HostClassFactory, IClassFactory>
{
HostClassFactory(winrt::guid g) :
_guid{ g } {};
HRESULT __stdcall CreateInstance(IUnknown* outer, GUID const& iid, void** result) noexcept final
{
*result = nullptr;
if (outer)
{
return CLASS_E_NOAGGREGATION;
}
if (!g_weak)
{
winrt::Microsoft::Terminal::Control::ContentProcess strong{};
winrt::weak_ref<winrt::Microsoft::Terminal::Control::ContentProcess> weak{ strong };
g_weak = weak;
return strong.as(iid, result);
}
else
{
auto strong = g_weak.get();
// !! LOAD BEARING !! If you set this event in the _first_ branch
// here, when we first create the object, then there will be _no_
// referernces to the ContentProcess object for a small slice. We'll
// stash the ContentProcess in the weak_ptr, and return it, and at
// that moment, there will be 0 outstanding references, it'll dtor,
// and wei'll ExitProcess.
//
// Instead, set the event here, once there's already a reference
// outside of just the weak one we keep. Experimentation showed this
// waw always hit when creating the ContentProcess at least once.
g_canExitThread.SetEvent();
return strong.as(iid, result);
}
}
HRESULT __stdcall LockServer(BOOL) noexcept final
{
return S_OK;
}
private:
winrt::guid _guid;
};
static void doContentProcessThing(const winrt::guid& contentProcessGuid, const HANDLE& eventHandle)
{
// !! LOAD BEARING !! - important to be a MTA for these COM calls.
winrt::init_apartment();
DWORD registrationHostClass{};
check_hresult(CoRegisterClassObject(contentProcessGuid,
make<HostClassFactory>(contentProcessGuid).get(),
make<ContentProcessFactory>(contentProcessGuid).get(),
CLSCTX_LOCAL_SERVER,
REGCLS_MULTIPLEUSE,
&registrationHostClass));