我這里只介紹采用ReadDirectoryChangesW對文件目錄實施監控
關鍵代碼
CfgdsgDlg * dlg = (CfgdsgDlg*)lparam; HANDLE hDir; char notify[1024]; DWORD cbBytes,i; char AnsiChar[3]; wchar_t UnicodeChar[2]; CString path; FILE_NOTIFY_INFORMATION *pnotify=(FILE_NOTIFY_INFORMATION *)notify; FILE_NOTIFY_INFORMATION *tmp; GetCurrentDirectory(MAX_PATH,path.GetBuffer(MAX_PATH+1)); hDir = CreateFile( path, FILE_LIST_DIRECTORY, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED, NULL); if (hDir == INVALID_HANDLE_VALUE) { dlg->m_edit.ReplaceSel("hDir:INVALID_HANDLE_VALUE/r/n"); return 0; } while (TRUE) { if(ReadDirectoryChangesW(hDir, ¬ify, sizeof(notify), FALSE, FILE_NOTIFY_CHANGE_FILE_NAME| FILE_NOTIFY_CHANGE_LAST_WRITE, &cbBytes, NULL, NULL)) { tmp = pnotify; switch(tmp->Action) { case FILE_ACTION_ADDED: dlg->m_edit.ReplaceSel("Directory/File added （添加文件）- /r/n"); break; case FILE_ACTION_REMOVED: dlg->m_edit.ReplaceSel("Directory/File removed （刪除文件）- /r/n"); break; case FILE_ACTION_MODIFIED: dlg->m_edit.ReplaceSel("Directory/File modified （修改文件內容）- /r/n"); break; case FILE_ACTION_RENAMED_OLD_NAME: dlg->m_edit.ReplaceSel("Directory/File old name （修改文件名字）- /r/n"); break; case FILE_ACTION_RENAMED_NEW_NAME: dlg->m_edit.ReplaceSel("Directory/File new name - /r/n"); break; default: break; } } }FILE_NOTIFY_INFORMATION //可以確定是那個文件進行的修改
typedef struct _FILE_NOTIFY_INFORMATION {
DWORD NextEntryOffset;
DWORD Action;//動作
DWORD FileNameLength;//文件名字的長度
WCHAR FileName[1];//文件名字
} FILE_NOTIFY_INFORMATION,
*PFILE_NOTIFY_INFORMATION;
ReadDirectoryChangesW 返回類型(見MSDN)
| Value | Meaning |
|---|---|
| FILE_ACTION_ADDED | The file was added to the directory. |
| FILE_ACTION_REMOVED | The file was removed from the directory. |
| FILE_ACTION_MODIFIED | The file was modified. This can be a change in the time stamp or attributes. |
| FILE_ACTION_RENAMED_OLD_NAME | The file was renamed and this is the old name. |
| FILE_ACTION_RENAMED_NEW_NAME | The file was renamed and this is the new name. |
效果如下：
不足的地方:
只能檢測到指定目錄和下一級目錄，超過目錄級數，該函數檢測不到。
ReadDirectoryChangesW 監控文件夾 (一個簡單的監控示例程序)
.h文件
// .h文件#pragma once typedef void (*PFN_NotifyAction)(DWORD dwAction, LPWSTR szFile, DWORD dwLength); class CDirectoryWatch{public: CDirectoryWatch(void); virtual ~CDirectoryWatch(void); public: BOOL StartDirectoryWatch(LPCTSTR lpszDirectory, PFN_NotifyAction pFn_NotifyAction); BOOL StopDirectoryWatch(void); private: static UINT __cdecl ThreadProc(LPVOID lParam); static UINT __cdecl DirectoryWatch(LPVOID lParam); private: HANDLE m_hFile; CWinThread* m_pThread; TCHAR m_szDirectory[MAX_PATH];};.cpp文件
// .cpp文件#include "StdAfx.h"#include "DirectoryWatch.h"#include <strsafe.h> typedef enum{ MSG_STARTWATCH = (WM_USER + 0x11), MSG_STOPWATCH, MSG_EXITTHREAD}; #define MAX_BUFFER_SIZE (1024) typedef struct _tagWATCHPARAMETERS{ _tagWATCHPARAMETERS() { hFile = INVALID_HANDLE_VALUE; hEvent = NULL; memset(&ol, 0, sizeof(OVERLAPPED)); pBuffer = NULL; dwBufferSize = 0; bExit = FALSE; pFn_NotifyAction = NULL; } HANDLE hFile; HANDLE hEvent; OVERLAPPED ol; BYTE* pBuffer; DWORD dwBufferSize; BOOL bExit; PFN_NotifyAction pFn_NotifyAction;}WATCH_PARAMETERS, *PWATCH_PARAMETERS; CDirectoryWatch::CDirectoryWatch() : m_hFile(INVALID_HANDLE_VALUE), m_pThread(NULL){ memset(m_szDirectory, 0, sizeof(m_szDirectory)); m_pThread = AfxBeginThread(ThreadProc, NULL, 0, CREATE_SUSPENDED, 0, NULL); if(NULL == m_pThread) { TRACE("Error Code : %d/n", GetLastError()); return ; } m_pThread->m_bAutoDelete = FALSE; m_pThread->ResumeThread();} CDirectoryWatch::~CDirectoryWatch(){ if(INVALID_HANDLE_VALUE != m_hFile) { CloseHandle(m_hFile); m_hFile = INVALID_HANDLE_VALUE; } if((NULL != m_pThread) && (NULL != m_pThread->m_hThread)) { m_pThread->PostThreadMessage(MSG_EXITTHREAD, 0, 0); WaitForSingleObject(m_pThread->m_hThread, INFINITE); delete m_pThread; m_pThread = NULL; }} BOOL CDirectoryWatch::StartDirectoryWatch(LPCTSTR lpszDirectory, PFN_NotifyAction pFn_NotifyAction){ if(NULL == m_pThread) { return FALSE; } if(NULL == lpszDirectory) { return FALSE; } if(NULL == pFn_NotifyAction) { return FALSE; } if(!PathFileExists(lpszDirectory)) { TRACE("Error Code : %d/n", GetLastError()); return FALSE; } if(!PathIsDirectory(lpszDirectory)) { TRACE("Error Code : %d/n", GetLastError()); return FALSE; } if(0 == _tcslen(m_szDirectory)) { StringCchPrintf(m_szDirectory, _countof(m_szDirectory), _T("%s"), lpszDirectory); } else if(CSTR_EQUAL != CompareStringOrdinal(m_szDirectory, -1, lpszDirectory, -1, TRUE)) { TRACE("Not Change Directory./n"); return FALSE; } if(INVALID_HANDLE_VALUE == m_hFile) { m_hFile = CreateFile(lpszDirectory, FILE_LIST_DIRECTORY, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED, NULL); if(INVALID_HANDLE_VALUE == m_hFile) { TRACE("Error Code : %d/n", GetLastError()); return FALSE; } } return m_pThread->PostThreadMessage(MSG_STARTWATCH, (WPARAM)m_hFile, (LPARAM)pFn_NotifyAction);} BOOL CDirectoryWatch::StopDirectoryWatch(){ if(NULL != m_pThread) { return m_pThread->PostThreadMessage(MSG_STOPWATCH, 0, 0); } return FALSE;} UINT __cdecl CDirectoryWatch::DirectoryWatch(LPVOID lParam){ WATCH_PARAMETERS* pParam = (WATCH_PARAMETERS*)lParam; if(NULL == pParam) { return 0; } HANDLE& hFile = pParam->hFile; BYTE* pBuffer = pParam->pBuffer; DWORD dwBufferSize = pParam->dwBufferSize; OVERLAPPED& ol = pParam->ol; HANDLE& hEvent = pParam->hEvent; BOOL& bExit = pParam->bExit; PFN_NotifyAction pFn_NotifyAction = pParam->pFn_NotifyAction; DWORD dwBytesReturn = 0; DWORD dwRet = WAIT_FAILED; DWORD dwOffSet = 0; TCHAR szFile[MAX_PATH] = {0}; while(TRUE) { if(WAIT_OBJECT_0 != WaitForSingleObject(hEvent, INFINITE)) { TRACE("Error Code : %d/n", GetLastError()); break; } if(bExit) { break; } if(!ReadDirectoryChangesW(hFile, pBuffer, dwBufferSize, TRUE, FILE_NOTIFY_CHANGE_FILE_NAME | FILE_NOTIFY_CHANGE_DIR_NAME | FILE_NOTIFY_CHANGE_ATTRIBUTES | FILE_NOTIFY_CHANGE_SIZE | FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_LAST_ACCESS | FILE_NOTIFY_CHANGE_CREATION | FILE_NOTIFY_CHANGE_SECURITY, &dwBytesReturn, &ol, NULL)) { TRACE("Error Code : %d/n", GetLastError()); break; } if(!GetOverlappedResult(hFile, &ol, &dwBytesReturn, TRUE)) { TRACE("Error Code : %d/n", GetLastError()); break; } FILE_NOTIFY_INFORMATION* pFileNotify = (FILE_NOTIFY_INFORMATION*)pBuffer; do { if(pFn_NotifyAction && (WAIT_OBJECT_0 == WaitForSingleObject(hEvent, 0))) { pFn_NotifyAction(pFileNotify->Action, pFileNotify->FileName, (pFileNotify->FileNameLength) / sizeof(WCHAR)); } dwOffSet = pFileNotify->NextEntryOffset; pFileNotify = (FILE_NOTIFY_INFORMATION*)((BYTE*)pFileNotify + dwOffSet); } while (dwOffSet); } TRACE0("DirectoryWatch Thread Exit ... /n"); return 0;} UINT __cdecl CDirectoryWatch::ThreadProc(LPVOID lParam){ WATCH_PARAMETERS* pParam = new WATCH_PARAMETERS; if(NULL == pParam) { goto __CLEANUP__; } BYTE* pBuffer = new BYTE[MAX_BUFFER_SIZE]; if(NULL == pBuffer) { goto __CLEANUP__; } memset(pBuffer, 0, MAX_BUFFER_SIZE); pParam->pBuffer = pBuffer; pParam->dwBufferSize = MAX_BUFFER_SIZE; HANDLE hWatchEvent = CreateEvent(NULL, TRUE, FALSE, NULL); if(NULL == hWatchEvent) { goto __CLEANUP__; } pParam->ol.hEvent = hWatchEvent; CWinThread* pThread = NULL; HANDLE hEvent = CreateEvent(NULL, TRUE, FALSE, NULL); if(NULL == hEvent) { goto __CLEANUP__; } pParam->hEvent = hEvent; MSG msg; while(GetMessage(&msg, NULL, 0, 0)) { switch(msg.message) { case MSG_STARTWATCH: { HANDLE hFile = (HANDLE)(msg.wParam); PFN_NotifyAction pFn_NotifyAction = (PFN_NotifyAction)(msg.lParam); if((INVALID_HANDLE_VALUE == hFile) && (NULL == pFn_NotifyAction)) { break; } if(NULL == pThread) { pParam->hFile = hFile; pParam->pFn_NotifyAction = pFn_NotifyAction; pThread = AfxBeginThread(DirectoryWatch, (LPVOID)pParam, 0, CREATE_SUSPENDED, NULL); if(NULL == pThread) { goto __CLEANUP__; } pThread->m_bAutoDelete = FALSE; pThread->ResumeThread(); } SetEvent(hEvent); } break; case MSG_STOPWATCH: { ResetEvent(hEvent); } break; case MSG_EXITTHREAD: { SetEvent(hEvent); pParam->bExit = FALSE; if((NULL != pThread) && (NULL != pThread->m_hThread)) { WaitForSingleObject(pThread->m_hThread, INFINITE); delete pThread; pThread = NULL; } goto __CLEANUP__; } default: break; } TranslateMessage(&msg); DispatchMessage(&msg); } __CLEANUP__: if(NULL != hWatchEvent) { CloseHandle(hWatchEvent); hWatchEvent = NULL; } if(NULL != pBuffer) { delete[] pBuffer; pBuffer = NULL; } if(NULL != pParam) { delete pParam; pParam = NULL; } TRACE0("ThreadProc Thread Exit .../n"); return 0;}測試代碼
// 測試代碼 #include "stdafx.h" #include "DirectoryWatch.h" void NotifyAction(DWORD dwAction, LPWSTR szFile, DWORD dwLength){ switch(dwAction) { case FILE_ACTION_ADDED: wprintf(L"FILE_ACTION_ADDED: /n/t"); break; case FILE_ACTION_REMOVED: wprintf(L"FILE_ACTION_REMOVED: /n/t"); break; case FILE_ACTION_MODIFIED: wprintf(L"FILE_ACTION_MODIFIED: /n/t"); break; case FILE_ACTION_RENAMED_OLD_NAME: wprintf(L"FILE_ACTION_RENAMED_OLD_NAME: /n/t"); break; case FILE_ACTION_RENAMED_NEW_NAME: wprintf(L"FILE_ACTION_RENAMED_NEW_NAME: /n/t"); break; default: break; } WCHAR szPath[MAX_PATH] = {0}; wmemcpy(szPath, szFile, min(dwLength, MAX_PATH)); wprintf(L"%s/n", szPath);} int _tmain(int argc, TCHAR* argv[], TCHAR* envp[]){ CDirectoryWatch watch; wprintf(L"Start Directory Watch .../n"); watch.StartDirectoryWatch(_T("F://11"), NotifyAction); Sleep(30 * 1000); watch.StopDirectoryWatch(); wprintf(L"Stop Directory Watch .../n"); Sleep(10 * 1000); wprintf(L"Start Directory Watch .../n"); watch.StartDirectoryWatch(_T("F://11"), NotifyAction); Sleep(30 * 1000); watch.StopDirectoryWatch(); wprintf(L"Stop Directory Watch .../n"); Sleep(30 * 1000); wprintf(L"Process Exit .../n"); return 0;}效果如下圖所示：
使用ReadDirectoryChangesW API監控文件系統的改變
在C++中若想要監控檔案系統改變有很多方法，可以用FindFirstChangeNotification取得檔案變更、或是Hook底層的API等方法來實現，這邊使用ReadDirectoryChangesW API來實現，該API使用前必須先加入Kernel32.lib。
并加入Windows.h的標頭檔
#include "Windows.h"
這些步驟做完后在程式中就可以看到ReadDirectoryChangesW API了，其函式原型如下：
BOOL WINAPI ReadDirectoryChangesW( __in HANDLE hDirectory, __out LPVOID lpBuffer, __in DWORD nBufferLength, __in BOOL bWatchSubtree, __in DWORD dwNotifyFilter, __out_opt LPDWORD lpBytesReturned, __inout_opt LPOVERLAPPED lpOverlapped, __in_opt LPOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine);
該API必須帶入八個參數，hDirectory帶入的是要監控的目錄Handle、lpBuffer帶入的是用來回傳變動資料的空間、nBufferLength是lpBuffer空間的大小、bWatchSubtree是指定是否偵測子目錄、dwNotifyFilter是指定監控的目錄有哪些動作時需要通知、lpBytesReturned是用來回傳變動資料內含的長度、lpOverlapped可用來在非同步環境下使用重疊IO用、lpCompletionRoutine則是當監控完成或取消時所呼叫的回調函式。
其中dwNotifyFilter的值可設定的有FILE_NOTIFY_CHANGE_FILE_NAME、FILE_NOTIFY_CHANGE_DIR_NAME、FILE_NOTIFY_CHANGE_ATTRIBUTES、FILE_NOTIFY_CHANGE_SIZE、FILE_NOTIFY_CHANGE_LAST_WRITE、FILE_NOTIFY_CHANGE_LAST_ACCESS、FILE_NOTIFY_CHANGE_CREATION、與FILE_NOTIFY_CHANGE_SECURITY，詳細所代表的意義可參閱ReadDirectoryChangesW function
了解了函式原型后，就可以開始進入實際的使用。剛有提到說在ReadDirectoryChangesW API函式必須要帶入的第一個參數是要監控的目錄Handle，所以我們必須透過CreateFile API取得要監控的目錄Handle，像是下面這樣：
HANDLE hDirectoryHandle = NULL;hDirectoryHandle = ::CreateFileA( file, FILE_LIST_DIRECTORY, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS | FILE_FLAG_OVERLAPPED, NULL); if(hDirectoryHandle == INVALID_HANDLE_VALUE) return;
取得監控的目錄Handle后，將其帶入ReadDirectoryChangesw API，順帶帶入像是回傳變動資料的Buffer空間、與要監控的變動類型等必要參數。像是下面這樣：
int nBufferSize = 1024;char* buffer = new char[nBufferSize];DWORD dwBytes = 0;memset(buffer, 0, nBufferSize);if(!::ReadDirectoryChangesW( hDirectoryHandle, buffer, nBufferSize, bIncludeSubdirectories, FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_CREATION | FILE_NOTIFY_CHANGE_FILE_NAME, &dwBytes, NULL, NULL) || GetLastError() == ERROR_INVALID_HANDLE){ break;}if(!dwBytes){ printf("Buffer overflow~~/r/n");}這邊需注意到的是，若是變動的資料太多，提供的存儲空間不足以存放時，回傳的變動資料長度會是0，此時所有變動資料都會丟失。這樣的情況多半只會出在一瞬間大量的變動，可以增大存儲空間或是減少監控的變動類型，以減少回傳的資料量，避免溢位的發生。
若是運行沒發生問題，變動的資料會存放在當初塞進去的存儲空間，該空間的資料其實是FILE_NOTIFY_INFORMATION structure的型態存在，因此我們可將存儲空間的資料轉換成PFILE_NOTIFY_INFORMATION。 主站蜘蛛池模板： 郴州市| 仪征市| 家居| 广水市| 微山县| 曲麻莱县| 邵东县| 韶关市| 新兴县| 浮梁县| 宁强县| 河曲县| 吉安县| 临朐县| 互助| 南川市| 夏河县| 花垣县| 天台县| 贵州省| 巴彦淖尔市| 璧山县| 都兰县| 闵行区| 丽水市| 汶上县| 江山市| 延安市| 巍山| 岱山县| 鄂托克前旗| 衢州市| 肃宁县| 和硕县| 那坡县| 霍林郭勒市| 丰都县| 榆林市| 桐梓县| 轮台县| 加查县|