4.1

1 files changed, 493 insertions, 0 deletions

diff --git a/zen/dir_watcher.cpp b/zen/dir_watcher.cpp
new file mode 100644
index 00000000..7b45b014
--- /dev/null
+++ b/zen/dir_watcher.cpp
@@ -0,0 +1,493 @@
+// **************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
+// * Copyright (C) 2008-2011 ZenJu (zhnmju123 AT gmx.de)                    *
+// **************************************************************************
+
+#include "dir_watcher.h"
+#include <algorithm>
+#include <set>
+#include "thread.h" //includes <boost/thread.hpp>
+#include "scope_guard.h"
+
+#ifdef FFS_WIN
+#include "notify_removal.h"
+#include "win.h" //includes "windows.h"
+#include "long_path_prefix.h"
+#include "privilege.h"
+
+#elif defined FFS_LINUX
+#include <sys/inotify.h>
+#include <fcntl.h>
+#include "file_traverser.h"
+#endif
+
+
+using namespace zen;
+
+#ifdef FFS_WIN
+namespace
+{
+inline
+bool errorCodeForNotExisting(const DWORD lastError)
+{
+    return lastError == ERROR_PATH_NOT_FOUND ||
+           lastError == ERROR_BAD_NETPATH    ||
+           lastError == ERROR_NETNAME_DELETED;
+}
+
+
+class SharedData
+{
+public:
+    //context of worker thread
+    void addChanges(const char* buffer, DWORD bytesWritten, const Zstring& dirname) //throw ()
+    {
+        boost::lock_guard<boost::mutex> dummy(lockAccess);
+
+        std::set<Zstring>& output = changedFiles;
+
+        if (bytesWritten == 0) //according to docu this may happen in case of internal buffer overflow: report some "dummy" change
+            output.insert(L"Overflow!");
+        else
+        {
+            const char* bufPos = &buffer[0];
+            for(;;)
+            {
+                const FILE_NOTIFY_INFORMATION& notifyInfo = reinterpret_cast<const FILE_NOTIFY_INFORMATION&>(*bufPos);
+
+                const Zstring fullname = dirname + Zstring(notifyInfo.FileName, notifyInfo.FileNameLength / sizeof(WCHAR));
+
+                //skip modifications sent by changed directories: reason for change, child element creation/deletion, will notify separately!
+                [&]()
+                {
+                    if (notifyInfo.Action == FILE_ACTION_RENAMED_OLD_NAME) //reporting FILE_ACTION_RENAMED_NEW_NAME should suffice
+                        return;
+
+                    if (notifyInfo.Action == FILE_ACTION_MODIFIED)
+                    {
+                        //note: this check will not work if top watched directory has been renamed
+                        const DWORD ret = ::GetFileAttributes(applyLongPathPrefix(fullname).c_str());
+                        if (ret != INVALID_FILE_ATTRIBUTES && (ret & FILE_ATTRIBUTE_DIRECTORY)) //returns true for (dir-)symlinks also
+                            return;
+                    }
+
+                    output.insert(fullname);
+                }();
+
+                if (notifyInfo.NextEntryOffset == 0)
+                    break;
+                bufPos += notifyInfo.NextEntryOffset;
+            }
+        }
+    }
+
+    //context of main thread
+    void addChange(const Zstring& dirname) //throw ()
+    {
+        boost::lock_guard<boost::mutex> dummy(lockAccess);
+        changedFiles.insert(dirname);
+    }
+
+
+    //context of main thread
+    void getChanges(std::vector<Zstring>& output) //throw FileError, ErrorNotExisting
+    {
+        boost::lock_guard<boost::mutex> dummy(lockAccess);
+
+        //first check whether errors occured in thread
+        if (!errorMsg.first.empty())
+        {
+            const std::wstring msg = errorMsg.first.c_str();
+            const DWORD lastError = errorMsg.second;
+
+            if (errorCodeForNotExisting(lastError))
+                throw ErrorNotExisting(msg);
+            throw FileError(msg);
+        }
+
+        output.assign(changedFiles.begin(), changedFiles.end());
+        changedFiles.clear();
+    }
+
+
+    //context of worker thread
+    void reportError(const std::wstring& msg, DWORD errorCode) //throw()
+    {
+        boost::lock_guard<boost::mutex> dummy(lockAccess);
+        errorMsg = std::make_pair(cvrtString<BasicWString>(msg), errorCode);
+    }
+
+private:
+    typedef Zbase<wchar_t> BasicWString; //thread safe string class for UI texts
+
+    boost::mutex lockAccess;
+    std::set<Zstring> changedFiles; //get rid of duplicate entries (actually occur!)
+    std::pair<BasicWString, DWORD> errorMsg; //non-empty if errors occured in thread
+};
+
+
+class ReadChangesAsync
+{
+public:
+    //constructed in main thread!
+    ReadChangesAsync(const Zstring& directory, //make sure to not leak in thread-unsafe types!
+                     const std::shared_ptr<SharedData>& shared) :
+        shared_(shared),
+        dirname(directory)
+    {
+        if (!endsWith(dirname, FILE_NAME_SEPARATOR))
+            dirname += FILE_NAME_SEPARATOR;
+
+        //these two privileges are required by ::CreateFile FILE_FLAG_BACKUP_SEMANTICS according to
+        //http://msdn.microsoft.com/en-us/library/aa363858(v=vs.85).aspx
+        try
+        {
+            Privileges::getInstance().ensureActive(SE_BACKUP_NAME);  //throw FileError
+            Privileges::getInstance().ensureActive(SE_RESTORE_NAME); //
+        }
+        catch (const FileError&) {}
+
+        hDir = ::CreateFile(applyLongPathPrefix(dirname.c_str()).c_str(),
+                            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 )
+        {
+            const std::wstring errorMsg = _("Could not initialize directory monitoring:") + "\n\"" + utf8CvrtTo<std::wstring>(dirname) + "\"" + "\n\n" + zen::getLastErrorFormatted();
+            if (errorCodeForNotExisting(::GetLastError()))
+                throw ErrorNotExisting(errorMsg);
+            throw FileError(errorMsg);
+        }
+
+        //end of constructor, no need to start managing "hDir"
+    }
+
+    ~ReadChangesAsync()
+    {
+        if (hDir != INVALID_HANDLE_VALUE)
+            ::CloseHandle(hDir);
+    }
+
+    void operator()() //thread entry
+    {
+        try
+        {
+            std::vector<char> buffer(64 * 1024); //needs to be aligned on a DWORD boundary; maximum buffer size restricted by some networks protocols (according to docu)
+
+            for(;;)
+            {
+                boost::this_thread::interruption_point();
+
+                //actual work
+                OVERLAPPED overlapped = {};
+                overlapped.hEvent = ::CreateEvent(NULL,  //__in_opt  LPSECURITY_ATTRIBUTES lpEventAttributes,
+                                                  true,  //__in      BOOL bManualReset,
+                                                  false, //__in      BOOL bInitialState,
+                                                  NULL); //__in_opt  LPCTSTR lpName
+                if (overlapped.hEvent == NULL)
+                    return shared_->reportError(_("Error when monitoring directories.") + " (CreateEvent)" + "\n\n" + getLastErrorFormatted(), ::GetLastError());
+                ZEN_ON_BLOCK_EXIT(::CloseHandle(overlapped.hEvent));
+
+                //asynchronous variant: runs on this thread's APC queue!
+                if (!::ReadDirectoryChangesW(hDir,                          //  __in         HANDLE hDirectory,
+                                             &buffer[0],                    //  __out        LPVOID lpBuffer,
+                                             static_cast<DWORD>(buffer.size()), //  __in         DWORD nBufferLength,
+                                             true,                          //  __in         BOOL bWatchSubtree,
+                                             FILE_NOTIFY_CHANGE_FILE_NAME |
+                                             FILE_NOTIFY_CHANGE_DIR_NAME  |
+                                             FILE_NOTIFY_CHANGE_SIZE      |
+                                             FILE_NOTIFY_CHANGE_LAST_WRITE, //  __in         DWORD dwNotifyFilter,
+                                             NULL,                          //  __out_opt    LPDWORD lpBytesReturned,
+                                             &overlapped,                   //  __inout_opt  LPOVERLAPPED lpOverlapped,
+                                             NULL))                    //  __in_opt     LPOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine
+                    return shared_->reportError(_("Error when monitoring directories.") + " (ReadDirectoryChangesW)" + "\n\n" + getLastErrorFormatted(), ::GetLastError());
+
+                //async I/O is a resource that needs to be guarded since it will write to local variable "buffer"!
+                zen::ScopeGuard lockAio = zen::makeGuard([&]()
+                {
+                    //http://msdn.microsoft.com/en-us/library/aa363789(v=vs.85).aspx
+                    if (::CancelIo(hDir) == TRUE) //cancel all async I/O related to this handle and thread
+                    {
+                        DWORD bytesWritten = 0;
+                        ::GetOverlappedResult(hDir, &overlapped, &bytesWritten, true); //wait until cancellation is complete
+                    }
+                });
+
+                DWORD bytesWritten = 0;
+
+                //wait for results
+                while (!::GetOverlappedResult(hDir,          //__in   HANDLE hFile,
+                                              &overlapped,   //__in   LPOVERLAPPED lpOverlapped,
+                                              &bytesWritten, //__out  LPDWORD lpNumberOfBytesTransferred,
+                                              false))        //__in   BOOL bWait
+                {
+                    if (::GetLastError() != ERROR_IO_INCOMPLETE)
+                        return shared_->reportError(_("Error when monitoring directories.") + " (GetOverlappedResult)" + "\n\n" + getLastErrorFormatted(), ::GetLastError());
+
+                    //execute asynchronous procedure calls (APC) queued on this thread
+                    ::SleepEx(50,    // __in  DWORD dwMilliseconds,
+                              true); // __in  BOOL bAlertable
+
+                    boost::this_thread::interruption_point();
+                }
+                lockAio.dismiss();
+
+                shared_->addChanges(&buffer[0], bytesWritten, dirname); //throw ()
+            }
+        }
+        catch (boost::thread_interrupted&)
+        {
+            throw; //this is the only reasonable exception!
+        }
+    }
+
+    ReadChangesAsync(ReadChangesAsync && other) :
+        hDir(INVALID_HANDLE_VALUE)
+    {
+        shared_ = std::move(other.shared_);
+        dirname = std::move(other.dirname);
+        std::swap(hDir, other.hDir);
+    }
+
+    HANDLE getDirHandle() const { return hDir; } //for reading purposes only, don't abuse (e.g. close handle)!
+
+private:
+    //shared between main and worker:
+    std::shared_ptr<SharedData> shared_;
+    //worker thread only:
+    Zstring dirname; //thread safe!
+    HANDLE hDir;
+};
+
+
+class HandleVolumeRemoval : public NotifyRequestDeviceRemoval
+{
+public:
+    HandleVolumeRemoval(HANDLE hDir,
+                        boost::thread& worker,
+                        const std::shared_ptr<SharedData>& shared,
+                        const Zstring& dirname) :
+        NotifyRequestDeviceRemoval(hDir), //throw FileError
+        worker_(worker),
+        shared_(shared),
+        dirname_(dirname),
+        removalRequested(false),
+        operationComplete(false) {}
+
+    //all functions are called by main thread!
+
+    bool requestReceived() const { return removalRequested; }
+    bool finished() const { return operationComplete; }
+
+private:
+    virtual void onRequestRemoval(HANDLE hnd)
+    {
+        //must release hDir immediately => stop monitoring!
+        worker_.interrupt();
+        worker_.join();
+        //now hDir should have been released
+
+        //report removal as change to main directory
+        shared_->addChange(dirname_);
+
+        removalRequested = true;
+    } //don't throw!
+    virtual void onRemovalFinished(HANDLE hnd, bool successful) { operationComplete = true; } //throw()!
+
+    boost::thread& worker_;
+    std::shared_ptr<SharedData> shared_;
+    Zstring dirname_;
+    bool removalRequested;
+    bool operationComplete;
+};
+}
+
+
+struct DirWatcher::Pimpl
+{
+    boost::thread worker;
+    std::shared_ptr<SharedData> shared;
+
+    std::unique_ptr<HandleVolumeRemoval> volRemoval;
+};
+
+
+DirWatcher::DirWatcher(const Zstring& directory) : //throw FileError
+    pimpl_(new Pimpl)
+{
+    pimpl_->shared = std::make_shared<SharedData>();
+
+    ReadChangesAsync reader(directory, pimpl_->shared); //throw FileError
+    pimpl_->volRemoval.reset(new HandleVolumeRemoval(reader.getDirHandle(), pimpl_->worker, pimpl_->shared, directory)); //throw FileError
+    pimpl_->worker = boost::thread(std::move(reader));
+}
+
+
+DirWatcher::~DirWatcher()
+{
+    pimpl_->worker.interrupt();
+    //pimpl_->worker.join(); -> we don't have time to wait... will take ~50ms anyway
+    //caveat: exitting the app may simply kill this thread!
+
+    //wait until device removal is confirmed, to (hopefully!) prevent locking hDir again by new watch!
+    if (pimpl_->volRemoval->requestReceived())
+    {
+        const boost::system_time maxwait = boost::get_system_time() + boost::posix_time::seconds(3); //HandleVolumeRemoval::finished() not guaranteed!
+
+        while (!pimpl_->volRemoval->finished() && boost::get_system_time() < maxwait)
+            boost::thread::sleep(boost::get_system_time() + boost::posix_time::milliseconds(50));
+    }
+}
+
+
+std::vector<Zstring> DirWatcher::getChanges() //throw FileError
+{
+    std::vector<Zstring> output;
+    pimpl_->shared->getChanges(output); //throw FileError
+    return output;
+}
+
+
+#elif defined FFS_LINUX
+struct DirWatcher::Pimpl
+{
+    int notifDescr;
+    std::map<int, Zstring> watchDescrs; //watch descriptor and corresponding directory name (postfixed with separator!)
+};
+
+
+namespace
+{
+class DirsOnlyTraverser : public zen::TraverseCallback
+{
+public:
+    DirsOnlyTraverser(std::vector<Zstring>& dirs) : dirs_(dirs) {}
+
+    virtual         void onFile   (const Zchar* shortName, const Zstring& fullName, const FileInfo& details) {}
+    virtual         void onSymlink(const Zchar* shortName, const Zstring& fullName, const SymlinkInfo& details) {}
+    virtual ReturnValDir onDir    (const Zchar* shortName, const Zstring& fullName)
+    {
+        dirs_.push_back(fullName);
+        return ReturnValDir(zen::Int2Type<ReturnValDir::TRAVERSING_DIR_CONTINUE>(), *this);
+    }
+    virtual HandleError onError(const std::wstring& errorText) { throw FileError(errorText); }
+
+private:
+    std::vector<Zstring>& dirs_;
+};
+}
+
+
+DirWatcher::DirWatcher(const Zstring& directory) : //throw FileError
+    pimpl_(new Pimpl)
+{
+    //still in main thread
+    Zstring dirname = directory;
+    if (endsWith(dirname, FILE_NAME_SEPARATOR))
+        dirname.resize(dirname.size() - 1);
+
+    //get all subdirectories
+    std::vector<Zstring> fullDirList;
+    fullDirList.push_back(dirname);
+
+    DirsOnlyTraverser traverser(fullDirList); //throw FileError
+    zen::traverseFolder(dirname, false, traverser); //don't traverse into symlinks (analog to windows build)
+
+    //init
+    pimpl_->notifDescr = ::inotify_init();
+    if (pimpl_->notifDescr == -1)
+        throw FileError(_("Could not initialize directory monitoring:") + "\n\"" + dirname + "\"" + "\n\n" + getLastErrorFormatted());
+
+    zen::ScopeGuard guardDescr = zen::makeGuard([&]() { ::close(pimpl_->notifDescr); });
+
+    //set non-blocking mode
+    bool initSuccess = false;
+    int flags = ::fcntl(pimpl_->notifDescr, F_GETFL);
+    if (flags != -1)
+        initSuccess = ::fcntl(pimpl_->notifDescr, F_SETFL, flags | O_NONBLOCK) != -1;
+
+    if (!initSuccess)
+        throw FileError(_("Could not initialize directory monitoring:") + "\n\"" + dirname + "\"" + "\n\n" + getLastErrorFormatted());
+
+    //add watches
+    std::for_each(fullDirList.begin(), fullDirList.end(),
+                  [&](Zstring subdir)
+    {
+        int wd = ::inotify_add_watch(pimpl_->notifDescr, subdir.c_str(),
+                                     IN_ONLYDIR     | //watch directories only
+                                     IN_DONT_FOLLOW | //don't follow symbolic links
+                                     IN_MODIFY 	    |
+                                     IN_CLOSE_WRITE |
+                                     IN_MOVE        |
+                                     IN_CREATE   	|
+                                     IN_DELETE 	    |
+                                     IN_DELETE_SELF |
+                                     IN_MOVE_SELF);
+        if (wd == -1)
+        {
+            std::wstring errorMsg = _("Could not initialize directory monitoring:") + "\n\"" + subdir + "\"" + "\n\n" + getLastErrorFormatted();
+            if (errno == ENOENT)
+                throw ErrorNotExisting(errorMsg);
+            throw FileError(errorMsg);
+        }
+
+        if (!endsWith(subdir, FILE_NAME_SEPARATOR))
+            subdir += FILE_NAME_SEPARATOR;
+        pimpl_->watchDescrs.insert(std::make_pair(wd, subdir));
+    });
+
+    guardDescr.dismiss();
+}
+
+
+DirWatcher::~DirWatcher()
+{
+    ::close(pimpl_->notifDescr); //associated watches are removed automatically!
+}
+
+
+std::vector<Zstring> DirWatcher::getChanges() //throw FileError
+{
+    std::vector<char> buffer(1024 * (sizeof(struct inotify_event) + 16));
+
+    //non-blocking call, see O_NONBLOCK
+    ssize_t bytesRead = ::read(pimpl_->notifDescr, &buffer[0], buffer.size());
+
+    if (bytesRead == -1)
+    {
+        if (errno == EINTR || //Interrupted function call; When this happens, you should try the call again.
+            errno == EAGAIN)  //Non-blocking I/O has been selected using O_NONBLOCK and no data was immediately available for reading
+            return std::vector<Zstring>();
+
+        throw FileError(_("Error when monitoring directories.") + "\n\n" + getLastErrorFormatted());
+    }
+
+    std::set<Zstring> tmp; //get rid of duplicate entries (actually occur!)
+
+    ssize_t bytePos = 0;
+    while (bytePos < bytesRead)
+    {
+        struct inotify_event& evt = reinterpret_cast<struct inotify_event&>(buffer[bytePos]);
+
+        if (evt.len != 0) //exclude case: deletion of "self", already reported by parent directory watch
+        {
+            auto iter = pimpl_->watchDescrs.find(evt.wd);
+            if (iter != pimpl_->watchDescrs.end())
+            {
+                //Note: evt.len is NOT the size of the evt.name c-string, but the array size including all padding 0 characters!
+                //It may be even 0 in which case evt.name must not be used!
+                tmp.insert(iter->second + evt.name);
+            }
+        }
+
+        bytePos += sizeof(struct inotify_event) + evt.len;
+    }
+
+    return std::vector<Zstring>(tmp.begin(), tmp.end());
+}
+
+#endif