Windows核心编程学习九：利用内核对象进行线程同步

注：源码为学习《Windows核心编程》的一些尝试，非原创。若能有助于一二访客，幸甚。

1.程序框架

#include "Queue.h"#include <tchar.h>#include <windowsx.h>#include <StrSafe.h>#include <process.h>#include "resource.h"/************************************************************************/#define chHANDLE_DLGMSG(hWnd, message, fn)                 \   case (message): return (SetDlgMsgResult(hWnd, uMsg,     \      HANDLE_##message((hWnd), (wParam), (lParam), (fn))))// This macro function calls the C runtime's _beginthreadex function. // The C runtime library doesn't want to have any reliance on Windows' data // types such as HANDLE. This means that a Windows programmer needs to cast// values when using _beginthreadex. Since this is terribly inconvenient, // I created this macro to perform the casting.typedef unsigned (__stdcall *PTHREAD_START) (void *);#define chBEGINTHREADEX(psa, cbStackSize, pfnStartAddr, \   pvParam, dwCreateFlags, pdwThreadId)                 \        ((HANDLE)_beginthreadex(                        \         (void *)        (psa),                         \         (unsigned)      (cbStackSize),                 \         (PTHREAD_START) (pfnStartAddr),                \         (void *)        (pvParam),                     \         (unsigned)      (dwCreateFlags),               \         (unsigned *)    (pdwThreadId)))// Sets the dialog box iconsinline void chSETDLGICONS(HWND hWnd, int idi) {   SendMessage(hWnd, WM_SETICON, ICON_BIG,  (LPARAM)       LoadIcon((HINSTANCE) GetWindowLongPtr(hWnd, GWLP_HINSTANCE), MAKEINTRESOURCE(idi)));   SendMessage(hWnd, WM_SETICON, ICON_SMALL, (LPARAM)       LoadIcon((HINSTANCE) GetWindowLongPtr(hWnd, GWLP_HINSTANCE), MAKEINTRESOURCE(idi)));}

BOOL Dlg_OnInitDialog(HWND hWnd, HWND hWndFocus, LPARAM lParam){chSETDLGICONS(hWnd, IDI_QUEUE);return TRUE;}void Dlg_OnCommand(HWND hWnd, int id, HWND hWndCtl, UINT codeNotify){switch (id){case IDCANCEL:EndDialog(hWnd, id);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){DialogBox(hInstExe, MAKEINTRESOURCE(IDD_QUEUE), NULL, Dlg_Proc);return 0;}

2.线程安全队列的实现

/* * File:CQueue.h * Time:2013-07-10 * 描述：学习《Windows核心编程》 */#ifndef _CQUEUE_H_#define _CQUEUE_H_#include <windows.h>class CQueue{public:struct ELEMENT {int m_nThreadNum;// 线程号int m_nRequestNum;// 请求号};typedef ELEMENT* PELEMENT;private:PELEMENTm_pElements;// 队列元素数组intm_nMaxElements;// 数组长度HANDLEm_h[2];// 两个内核对象，一个互斥量一个信号量HANDLE&m_hmtxQ;// 互斥量对象的引用HANDLE&m_hsemNumElements;// 信号量对象的引用public:CQueue(int nMaxElements);~CQueue();BOOL Append(PELEMENT pElement, DWORD dwMilliseconds);BOOL Remove(PELEMENT pElement, DWORD dwMilliseconds);};#endif

/************************************************************************/CQueue::CQueue(int nMaxElements) : m_hmtxQ(m_h[0]), m_hsemNumElements(m_h[1]){// 初始化结构数组m_pElements = (PELEMENT)HeapAlloc(GetProcessHeap(), 0, sizeof(ELEMENT) * nMaxElements);// 初始化数组长度m_nMaxElements = nMaxElements;// 创建互斥量和信号量内核对象m_hmtxQ = CreateMutex(NULL, FALSE, NULL);m_hsemNumElements = CreateSemaphore(NULL, 0, nMaxElements, NULL);}CQueue::~CQueue(){// 清理内核对象和内存CloseHandle(m_hsemNumElements);CloseHandle(m_hmtxQ);HeapFree(GetProcessHeap(), 0, m_pElements);}BOOL CQueue::Append(CQueue::PELEMENT pElement, DWORD dwTimeout){BOOL fOk = FALSE;// 等待互斥量内核对象DWORD dw = WaitForSingleObject(m_hmtxQ, dwTimeout);// 返回WAIT_OBJECT_0表示得到了队列的独占访问权if (dw == WAIT_OBJECT_0) {LONG lPrevCount;// 尝试向队列添加新元素fOk = ReleaseSemaphore(m_hsemNumElements, 1, &lPrevCount);// fOk为TRUE表示队列没满，可以添加新元素if (fOk) {m_pElements[lPrevCount] = *pElement;}else {SetLastError(ERROR_DATABASE_FULL);}// 释放互斥量，允许其他线程访问队列ReleaseMutex(m_hmtxQ);}else {SetLastError(ERROR_TIMEOUT);}return fOk;}BOOL CQueue::Remove(CQueue::PELEMENT pElement, DWORD dwTimeout){// 确保对队列具有独占访问权，且要求队列中有元素可取// 等待信号量成功的副作用使它的计数减一，所以不需要显示调用ReleaseSemaphore()BOOL fOk = (WaitForMultipleObjects(_countof(m_h), m_h, TRUE, dwTimeout) == WAIT_OBJECT_0);if (fOk){// 获取元素*pElement = m_pElements[0];// 取出索引为0 的元素，把数组中剩余元素向前挪一个位置MoveMemory(&m_pElements[0], &m_pElements[1], sizeof(ELEMENT) * (m_nMaxElements - 1));// 释放互斥量，允许其他线程访问队列ReleaseMutex(m_hmtxQ);}else{SetLastError(ERROR_TIMEOUT);}return fOk;}

3.客户端线程

CQueueg_q(10);volatile LONGg_fShutdown = FALSE;HWNDg_hWnd;// Handles to all reader/writer threadsHANDLE g_hThreads[MAXIMUM_WAIT_OBJECTS];// Number of reader/writer threads  int    g_nNumThreads = 0;/************************************************************************/DWORD WINAPI ClientThread(PVOID pvParam){int nThreadNum = PtrToUlong(pvParam);// 线程号HWND hWndLB = GetDlgItem(g_hWnd, IDC_CLIENT);int nRequestNum = 0;while (1 != InterlockedCompareExchange(&g_fShutdown, 0, 0)){nRequestNum++;TCHAR sz[1024];CQueue::ELEMENT e = { nThreadNum, nRequestNum };// 尝试添加元素到队列if (g_q.Append(&e, 200)) {StringCchPrintf(sz, _countof(sz), TEXT("客户线程%d 添加元素%d"), nThreadNum, nRequestNum);}else {StringCchPrintf(sz, _countof(sz), TEXT("客户线程%d 添加元素%d失败(%s)"), nThreadNum, nRequestNum,(GetLastError() == ERROR_TIMEOUT) ? TEXT("超时") : TEXT("队列已满"));}ListBox_SetCurSel(hWndLB, ListBox_AddString(hWndLB, sz));Sleep(2500);}return 0;}

BOOL Dlg_OnInitDialog(HWND hWnd, HWND hWndFocus, LPARAM lParam){chSETDLGICONS(hWnd, IDI_QUEUE);g_hWnd = hWnd;DWORD dwThreadID;// 创建客户端线程for (int i = 0; i < 4; i++)g_hThreads[g_nNumThreads++] = chBEGINTHREADEX(NULL, 0, ClientThread, (PVOID)(INT_PTR) i, 0, &dwThreadID);return TRUE;}

4.服务器端线程

DWORD WINAPI ServerThread(PVOID pvParam){int nThreadNum = PtrToUlong(pvParam);HWND hWndLB = GetDlgItem(g_hWnd, IDC_SERVER);while (1 != InterlockedCompareExchange(&g_fShutdown, 0, 0)) {TCHAR sz[1024];CQueue::ELEMENT e;// 尝试移除元素if (g_q.Remove(&e, 5000)) {StringCchPrintf(sz, _countof(sz), TEXT("服务器端线程%d移除客户端线程%d放入的元素%d"), nThreadNum, e.m_nThreadNum, e.m_nRequestNum);Sleep(2000 * e.m_nThreadNum);}else {StringCchPrintf(sz, _countof(sz), TEXT("服务器端线程%d 没有元素可取"), nThreadNum);}ListBox_SetCurSel(hWndLB, ListBox_AddString(hWndLB, sz));}return 0;}

BOOL Dlg_OnInitDialog(HWND hWnd, HWND hWndFocus, LPARAM lParam){chSETDLGICONS(hWnd, IDI_QUEUE);g_hWnd = hWnd;DWORD dwThreadID;// 创建客户端线程for (int i = 0; i < 4; i++)g_hThreads[g_nNumThreads++] = chBEGINTHREADEX(NULL, 0, ClientThread, (PVOID)(INT_PTR) i, 0, &dwThreadID);// 创建读者线程for (int i = 0; i < 2; i++)g_hThreads[g_nNumThreads++] = chBEGINTHREADEX(NULL, 0, ServerThread, (PVOID)(INT_PTR) i, 0, &dwThreadID);return TRUE;}

int WINAPI _tWinMain(HINSTANCE hInstExe, HINSTANCE, PTSTR pszCmdLine, int){DialogBox(hInstExe, MAKEINTRESOURCE(IDD_QUEUE), NULL, Dlg_Proc);InterlockedExchange(&g_fShutdown, TRUE);WaitForMultipleObjects(g_nNumThreads, g_hThreads, TRUE, INFINITE);while (g_nNumThreads--)CloseHandle(g_hThreads[g_nNumThreads]);return 0;}