我这里只介绍采用ReadDirectoryChangesW对文件目录实施监控
关键代码
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 （删除文件）- \r\n"); break; case FILE_ACTION_MODIFIED: dlg->m_edit.ReplaceSel("Directory/File modified （修改文件内容）- \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 //可以确定是那个文件进行的修改
typedef struct _FILE_NOTIFY_INFORMATION {
DWORD NextEntryOffset;
DWORD Action;//动作
DWORD FileNameLength;//文件名字的长度
WCHAR FileName[1];//文件名字
} FILE_NOTIFY_INFORMATION,
*PFILE_NOTIFY_INFORMATION;
ReadDirectoryChangesW 返回类型(见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:
只能检测到指定目录和下一级目录，超过目录级数，该函数检测不到。
ReadDirectoryChangesW 监控文件夹 (一个简单的监控示例程序)
.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; } 测试代码
// 测试代码 #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; } 效果如下图所示：
使用ReadDirectoryChangesW API监控文件系统的改变
在C++中若想要监控档案系统改变有很多方法，可以用FindFirstChangeNotification取得档案变更、或是Hook底层的API等方法来实现，这边使用ReadDirectoryChangesW API来实现，该API使用前必须先加入Kernel32.lib。
并加入Windows.h的标头档
#include "Windows.h"
这些步骤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 );
该API必须带入八个参数，hDirectory带入的是要监控的目录Handle、lpBuffer带入的是用来回传变动资料的空间、nBufferLength是lpBuffer空间的大小、bWatchSubtree是指定是否侦测子目录、dwNotifyFilter是指定监控的目录有哪些动作时需要通知、lpBytesReturned是用来回传变动资料内含的长度、lpOverlapped可用来在非同步环境下使用重叠IO用、lpCompletionRoutine则是当监控完成或取消时所呼叫的回调函式。
其中dwNotifyFilter的值可设定的有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、与FILE_NOTIFY_CHANGE_SECURITY，详细所代表的意义可参阅ReadDirectoryChangesW function
了解了函式原型后，就可以开始进入实际的使用。刚有提到说在ReadDirectoryChangesW API函式必须要带入的第一个参数是要监控的目录Handle，所以我们必须透过CreateFile API取得要监控的目录Handle，像是下面这样：
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;
取得监控的目录Handle后，将其带入ReadDirectoryChangesw API，顺带带入像是回传变动资料的Buffer空间、与要监控的变动类型等必要参数。像是下面这样：
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"); } 这边需注意到的是，若是变动的资料太多，提供的存储空间不足以存放时，回传的变动资料长度会是0，此时所有变动资料都会丢失。这样的情况多半只会出在一瞬间大量的变动，可以增大存储空间或是减少监控的变动类型，以减少回传的资料量，避免溢位的发生。
若是运行没发生问题，变动的资料会存放在当初塞进去的存储空间，该空间的资料其实是FILE_NOTIFY_INFORMATION structure的型态存在，因此我们可将存储空间的资料转换成PFILE_NOTIFY_INFORMATION。裡面的Action是我们所关注的变动类型，FileName是变动的档案名称，档案名称的部分是没有结尾符号的，必须要搭配FileNameLength去截取。另外变动的资料有时候不止一笔，因此我们必须在这边用迴圈搭配NextEntryOffset去重覆运行处理流程，处理所有变动的资料。
PFILE_NOTIFY_INFORMATION record = (PFILE_NOTIFY_INFORMATION)buffer; DWORD cbOffset = 0; do { switch (record->Action) { case FILE_ACTION_ADDED: printf("FILE_ACTION_ADDED:"); break; case FILE_ACTION_REMOVED: printf("FILE_ACTION_REMOVED:"); break; case FILE_ACTION_MODIFIED: printf("FILE_ACTION_MODIFIED:"); break; case FILE_ACTION_RENAMED_OLD_NAME: printf("FILE_ACTION_RENAMED_OLD_NAME:"); break; case FILE_ACTION_RENAMED_NEW_NAME: printf("FILE_ACTION_RENAMED_NEW_NAME:"); break; default: break; } char fileBuffer[512]; WideCharToMultiByte(CP_ACP, 0, record->FileName, record->FileNameLength, fileBuffer, record->FileNameLength, NULL, NULL); printf(fileBuffer); printf("\r\n"); cbOffset = record->NextEntryOffset; record = (PFILE_NOTIFY_INFORMATION)((LPBYTE) record + cbOffset); }while(cbOffset); 这边示范一个简易的使用范例，实际使用时最好还是搭配执行绪处理：
// ConsoleApplication10.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include "Windows.h" void MonitorDir(char* file, bool bIncludeSubdirectories = false) { int nBufferSize = 1024; char* buffer = new char[nBufferSize]; 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; while(1) { 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"); } PFILE_NOTIFY_INFORMATION record = (PFILE_NOTIFY_INFORMATION)buffer; DWORD cbOffset = 0; do { switch (record->Action) { case FILE_ACTION_ADDED: printf("FILE_ACTION_ADDED:"); break; case FILE_ACTION_REMOVED: printf("FILE_ACTION_REMOVED:"); break; case FILE_ACTION_MODIFIED: printf("FILE_ACTION_MODIFIED:"); break; case FILE_ACTION_RENAMED_OLD_NAME: printf("FILE_ACTION_RENAMED_OLD_NAME:"); break; case FILE_ACTION_RENAMED_NEW_NAME: printf("FILE_ACTION_RENAMED_NEW_NAME:"); break; default: break; } char fileBuffer[512]; WideCharToMultiByte(CP_ACP, 0, record->FileName, record->FileNameLength, fileBuffer, record->FileNameLength, NULL, NULL); printf(fileBuffer); printf("\r\n"); cbOffset = record->NextEntryOffset; record = (PFILE_NOTIFY_INFORMATION)((LPBYTE) record + cbOffset); }while(cbOffset); } delete buffer; if(hDirectoryHandle) CloseHandle(hDirectoryHandle); } int _tmain(int argc, _TCHAR* argv[]) { MonitorDir("C:\\Users\\larry\\Desktop\\新增資料夾"); 运行后去对监控的目录操作~可得到类似如下的结果：
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