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#include <utility>
#include <windows.h>
#include "win.h"
void WithNextWindow(void (*proc)(HWND))
{
/* WithNextWindow uses a CBT hook to call an arbitrary
* procedure just before the creation of the next window. The
* hook is removed as soon as HCBT_CREATEWND is received.
* Thus, proc is guaranteed to be executed only once. Note
* that static storage must be used, as SetWindowHookEx cannot
* accept a capturing lambda as the hook procedure. */
static __thread auto procNext = proc;
static __thread HHOOK hHook = Require(SetWindowsHookEx(WH_CBT, [](const int nCode,
const WPARAM wParam, const LPARAM lParam) -> LRESULT CALLBACK
{
if (nCode == HCBT_CREATEWND) {
Require(UnhookWindowsHookEx(hHook));
procNext(reinterpret_cast<HWND>(wParam));
return 0;
} else
return CallNextHookEx(0, nCode, wParam, lParam);
}, nullptr, GetCurrentThreadId()));
}
/* Display next created window in the center of given window. */
static void CenterNextWindow(HWND hWnd)
{
if (!hWnd)
return;
/* CenterNextWindow employs a trick similar to that above.
* Note, however, that repositioning does not work unless it
* is delayed until the new window is activated. This
* complicates the code somewhat. */
static __thread HWND hWndParent;
static __thread HWND hWndNext;
static __thread HHOOK hHook;
hWndParent = hWnd;
hWndNext = nullptr;
hHook = Require(SetWindowsHookEx(WH_CBT, [](const int nCode,
const WPARAM wParam, const LPARAM lParam) noexcept -> LRESULT CALLBACK
{
if (!hWndNext && nCode == HCBT_CREATEWND) {
hWndNext = reinterpret_cast<HWND>(wParam);
return 0;
} else if (nCode == HCBT_ACTIVATE
&& reinterpret_cast<HWND>(wParam) == hWndNext) {
Require(UnhookWindowsHookEx(hHook));
long lStyle = GetWindowLong(hWndNext, GWL_STYLE);
if (!(lStyle & WS_POPUP)) return 0;
RECT rcMain, rcMsg;
GetWindowRect(hWndParent, &rcMain);
GetWindowRect(hWndNext, &rcMsg);
SetWindowPos(hWndNext, nullptr,
rcMain.left+(rcMain.right-rcMain.left)/2-(rcMsg.right-rcMsg.left)/2,
rcMain.top+(rcMain.bottom-rcMain.top)/2-(rcMsg.bottom-rcMsg.top)/2,
-1, -1,
SWP_NOZORDER|SWP_NOSIZE|SWP_NOACTIVATE);
return 0;
} else
return CallNextHookEx(0, nCode, wParam, lParam);
}, nullptr, GetCurrentThreadId()));
}
int EBMessageBox(const std::wstring_view text, const std::wstring_view caption, const UINT uType)
{
extern HWND g_hWnd;
CenterNextWindow(g_hWnd);
return MessageBox(g_hWnd, text.data(), caption.data(), uType);
}
int GetRelativeCursorPos(const HWND hWnd, POINT* const pt) noexcept
{
RECT rc;
if (!GetClientRect(hWnd, &rc)) return 0;
SetLastError(ERROR_SUCCESS);
if (!MapWindowPoints(hWnd, nullptr, (POINT*)&rc, 2)) return 0;
POINT ptMouse;
if (!GetCursorPos(&ptMouse)) return 0;
pt->x = ptMouse.x-rc.left;
pt->y = ptMouse.y-rc.top;
return 1;
}
Win32Error::Win32Error() noexcept
: code(GetLastError()) {}
Win32Error::Win32Error(const DWORD code) noexcept
: code(code) {}
Win32Error::~Win32Error()
{
if (m_szMsg)
HeapFree(GetProcessHeap(), 0, m_szMsg);
if (m_wszMsg)
HeapFree(GetProcessHeap(), 0, m_wszMsg);
}
const char* Win32Error::what() const noexcept
{
if (!m_szMsg)
FormatMessageA(
FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
nullptr,
code,
MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
(char*)&m_szMsg,
0, nullptr);
return m_szMsg;
}
const wchar_t* Win32Error::What() const noexcept
{
if (!m_wszMsg)
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM|FORMAT_MESSAGE_IGNORE_INSERTS,
nullptr,
code,
MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
(wchar_t*)&m_wszMsg,
0, nullptr);
return m_wszMsg;
}
std::optional<Library> Library::Maybe(const wchar_t* const lib) noexcept
{
HMODULE hModule = LoadLibrary(lib);
if (!hModule) return {};
return Library(hModule);
}
Library::Library(const HMODULE hModule) noexcept
: m_hModule(hModule) {}
Library::Library(const wchar_t* const lib)
{
m_hModule = LoadLibrary(lib);
if (!m_hModule)
throw Win32Error();
}
Library::~Library()
{
FreeLibrary(m_hModule);
}
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