/****************************************************************************** Module: Counter.cpp Notices: Copyright (c) 2000 Jeffrey Richter ******************************************************************************/ #include "..\CmnHdr.h" /* See Appendix A. */ #include #include #include "Resource.h" /////////////////////////////////////////////////////////////////////////////// // The possible state of the background processing typedef enum { BPS_STARTOVER, // Start the background processing from the beginning. BPS_CONTINUE, // Continue the background processing. BPS_DONE // There is no background processing to do. } BKGNDPROCSTATE; typedef struct { PVOID pFiberUI; // User interface fiber execution context HWND hwnd; // Handle of main UI window BKGNDPROCSTATE bps; // State of background processing } FIBERINFO, *PFIBERINFO; // A global that contains application state information. This // global is accessed directly by the UI fiber and indirectly // by the background processing fiber. FIBERINFO g_FiberInfo; /////////////////////////////////////////////////////////////////////////////// void WINAPI FiberFunc(PVOID pvParam) { PFIBERINFO pFiberInfo = (PFIBERINFO) pvParam; // Update the window showing which fiber is executing. SetDlgItemText(pFiberInfo->hwnd, IDC_FIBER, TEXT("Recalculation")); // Get the current count in the EDIT control. int nCount = GetDlgItemInt(pFiberInfo->hwnd, IDC_COUNT, NULL, FALSE); // Count from 0 to nCount, updating the STATIC control. for (int x = 0; x pFiberUI); // The UI has no more events; continue counting. SetDlgItemText(pFiberInfo->hwnd, IDC_FIBER, TEXT("Recalculation")); } // Update the STATIC control with the most recent count. SetDlgItemInt(pFiberInfo->hwnd, IDC_ANSWER, x, FALSE); // Sleep for a while to exaggerate the effect; remove // the call to Sleep in production code. Sleep(200); } // Indicate that counting is complete. pFiberInfo->bps = BPS_DONE; // Reschedule the UI thread. When the UI thread is running // and has no events to process, the thread is put to sleep. // NOTE: If we just allow the fiber function to return, // the thread and the UI fiber die -- we don't want this! SwitchToFiber(pFiberInfo->pFiberUI); } /////////////////////////////////////////////////////////////////////////////// BOOL Dlg_OnInitDialog(HWND hwnd, HWND hwndFocus, LPARAM lParam) { chSETDLGICONS(hwnd, IDI_COUNTER); SetDlgItemInt(hwnd, IDC_COUNT, 0, FALSE); return(TRUE); } /////////////////////////////////////////////////////////////////////////////// void Dlg_OnCommand(HWND hwnd, int id, HWND hwndCtl, UINT codeNotify) { switch (id) { case IDCANCEL: PostQuitMessage(0); break; case IDC_COUNT: if (codeNotify == EN_CHANGE) { // When the user changes the count, start the // background processing over from the beginning. g_FiberInfo.bps = BPS_STARTOVER; } break; } } /////////////////////////////////////////////////////////////////////////////// INT_PTR WINAPI Dlg_Proc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch (uMsg) { chHANDLE_DLGMSG(hwnd, WM_INITDIALOG, Dlg_OnInitDialog); chHANDLE_DLGMSG(hwnd, WM_COMMAND, Dlg_OnCommand); } return(FALSE); } /////////////////////////////////////////////////////////////////////////////// int WINAPI _tWinMain(HINSTANCE hinstExe, HINSTANCE, PTSTR pszCmdLine, int) { // Counter fiber execution context PVOID pFiberCounter = NULL; // Convert this thread to a fiber. g_FiberInfo.pFiberUI = ConvertThreadToFiber(NULL); // Create the application's UI window. g_FiberInfo.hwnd = CreateDialog(hinstExe, MAKEINTRESOURCE(IDD_COUNTER), NULL, Dlg_Proc); // Update the window showing which fiber is executing. SetDlgItemText(g_FiberInfo.hwnd, IDC_FIBER, TEXT("User interface")); // Initially, there is no background processing to be done. g_FiberInfo.bps = BPS_DONE; // While the UI window still exists... BOOL fQuit = FALSE; while (!fQuit) { // UI messages are higher priority than background processing. MSG msg; if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { // If a message exists in the queue, process it. fQuit = (msg.message == WM_QUIT); if (!IsDialogMessage(g_FiberInfo.hwnd, &msg)) { TranslateMessage(&msg); DispatchMessage(&msg); } } else { // No UI msgs exist; check the state of the background processing. switch (g_FiberInfo.bps) { case BPS_DONE: // No background processing to do; wait for a UI event. WaitMessage(); break; case BPS_STARTOVER: // User changed the count; restart the background processing. if (pFiberCounter != NULL) { // A recalculation fiber exists; delete it so that // background processing starts over from the beginning. DeleteFiber(pFiberCounter); pFiberCounter = NULL; } // Create a new recalc fiber that starts from the beginning. pFiberCounter = CreateFiber(0, FiberFunc, &g_FiberInfo); // The background processing started; it should continue. g_FiberInfo.bps = BPS_CONTINUE; // Fall through to BPS_CONTINUE case... case BPS_CONTINUE: // Allow the background processing to execute... SwitchToFiber(pFiberCounter); // The background processing has been paused // (because a UI message showed up) or has been // stopped (because the counting has completed). // Update the window showing which fiber is executing. SetDlgItemText(g_FiberInfo.hwnd, IDC_FIBER, TEXT("User interface")); if (g_FiberInfo.bps == BPS_DONE) { // The background processing ran to completion. Delete the // fiber so that processing will restart next time. DeleteFiber(pFiberCounter); pFiberCounter = NULL; } break; } // switch on background processing state } // No UI messages exist } // while the window still exists DestroyWindow(g_FiberInfo.hwnd); return(0); // End the application. } //////////////////////////////// End of File //////////////////////////////////