C++ QFileSystemMetaData类代码示例

/*!
    \internal

    Returns the stdlib open string corresponding to a QIODevice::OpenMode.
*/
static inline QByteArray openModeToFopenMode(QIODevice::OpenMode flags, const QFileSystemEntry &fileEntry,
        QFileSystemMetaData &metaData)
{
    QByteArray mode;
    if ((flags & QIODevice::ReadOnly) && !(flags & QIODevice::Truncate)) {
        mode = "rb";
        if (flags & QIODevice::WriteOnly) {
            metaData.clearFlags(QFileSystemMetaData::FileType);
            if (!fileEntry.isEmpty()
                    && QFileSystemEngine::fillMetaData(fileEntry, metaData, QFileSystemMetaData::FileType)
                    && metaData.isFile()) {
                mode += '+';
            } else {
                mode = "wb+";
            }
        }
    } else if (flags & QIODevice::WriteOnly) {
        mode = "wb";
        if (flags & QIODevice::ReadOnly)
            mode += '+';
    }
    if (flags & QIODevice::Append) {
        mode = "ab";
        if (flags & QIODevice::ReadOnly)
            mode += '+';
    }

#if defined(__GLIBC__) && (__GLIBC__ * 0x100 + __GLIBC_MINOR__) >= 0x0207
    // must be glibc >= 2.7
    mode += 'e';
#endif

    return mode;
}

//static
QString QFileSystemEngine::resolveGroupName(const QFileSystemEntry &entry, QFileSystemMetaData &metaData)
{
#if defined(Q_OS_WIN)
    Q_UNUSED(metaData);
    return QFileSystemEngine::owner(entry, QAbstractFileEngine::OwnerGroup);
#else //(Q_OS_UNIX)
    if (!metaData.hasFlags(QFileSystemMetaData::GroupId))
        QFileSystemEngine::fillMetaData(entry, metaData, QFileSystemMetaData::GroupId);
    return resolveGroupName(metaData.groupId());
#endif
}

static inline bool _q_checkEntry(QFileSystemEntry &entry, QFileSystemMetaData &data, bool resolvingEntry)
{
    if (resolvingEntry) {
        if (!QFileSystemEngine::fillMetaData(entry, data, QFileSystemMetaData::ExistsAttribute)
                || !data.exists()) {
            data.clear();
            return false;
        }
    }

    return true;
}

/*!
    \since 5.2

    Returns \c true if the \a file exists; otherwise returns \c false.

    \note If \a file is a symlink that points to a non-existing
    file, false is returned.

    \note Using this function is faster than using
    \c QFileInfo(file).exists() for file system access.
*/
bool QFileInfo::exists(const QString &file)
{
    QFileSystemEntry entry(file);
    QFileSystemMetaData data;
    QAbstractFileEngine *engine =
        QFileSystemEngine::resolveEntryAndCreateLegacyEngine(entry, data);
    // Expensive fallback to non-QFileSystemEngine implementation
    if (engine)
        return QFileInfo(new QFileInfoPrivate(entry, data, engine)).exists();

    QFileSystemEngine::fillMetaData(entry, data, QFileSystemMetaData::ExistsAttribute);
    return data.exists();
}

//static
QString QFileSystemEngine::resolveUserName(const QFileSystemEntry &entry, QFileSystemMetaData &metaData)
{
#if defined (Q_OS_SYMBIAN)
    Q_UNUSED(entry);
    Q_UNUSED(metaData);
    return QString();
#elif defined(Q_OS_WIN)
    Q_UNUSED(metaData);
    return QFileSystemEngine::owner(entry, QAbstractFileEngine::OwnerUser);
#else //(Q_OS_UNIX)
    if (!metaData.hasFlags(QFileSystemMetaData::UserId))
        QFileSystemEngine::fillMetaData(entry, metaData, QFileSystemMetaData::UserId);
    return resolveUserName(metaData.userId());
#endif
}

//static
QFileSystemEntry QFileSystemEngine::canonicalName(const QFileSystemEntry &entry, QFileSystemMetaData &data)
{
    if (entry.isEmpty() || entry.isRoot())
        return entry;

    QFileSystemEntry result = absoluteName(entry);
    if (!data.hasFlags(QFileSystemMetaData::ExistsAttribute))
        fillMetaData(result, data, QFileSystemMetaData::ExistsAttribute);
    if (!data.exists()) {
        // file doesn't exist
        return QFileSystemEntry();
    } else {
        return result;
    }
}

QT_BEGIN_NAMESPACE

#if defined(Q_OS_DARWIN)
static inline bool hasResourcePropertyFlag(const QFileSystemMetaData &data,
                                           const QFileSystemEntry &entry,
                                           CFStringRef key)
{
    QCFString path = CFStringCreateWithFileSystemRepresentation(0,
        entry.nativeFilePath().constData());
    if (!path)
        return false;

    QCFType<CFURLRef> url = CFURLCreateWithFileSystemPath(0, path, kCFURLPOSIXPathStyle,
        data.hasFlags(QFileSystemMetaData::DirectoryType));
    if (!url)
        return false;

    CFBooleanRef value;
    if (CFURLCopyResourcePropertyForKey(url, key, &value, NULL)) {
        if (value == kCFBooleanTrue)
            return true;
    }

    return false;
}

bool QFileSystemIterator::advance(QFileSystemEntry &fileEntry, QFileSystemMetaData &metaData)
{
    //1st time, lastError is result of dirHandle.Open(), entries.Count() is 0 and entryIndex is -1 so initial read is triggered
    //subsequent times, read is triggered each time we reach the end of the entry list
    //final time, lastError is KErrEof so we don't need to read anymore.
    ++entryIndex;
    if (lastError == KErrNone && entryIndex >= entries.Count()) {
        lastError = dirHandle.Read(entries);
        entryIndex = 0;
    }

    //each call to advance() gets the next entry from the entry list.
    //from the final (or only) read call, KErrEof is returned together with a full buffer so we still need to go through the list
    if ((lastError == KErrNone || lastError == KErrEof) && entryIndex < entries.Count()) {
        Q_ASSERT(entryIndex >= 0);
        const TEntry &entry(entries[entryIndex]);
        fileEntry = QFileSystemEntry(nativePath + qt_TDesC2QString(entry.iName), QFileSystemEntry::FromNativePath());
        metaData.fillFromTEntry(entry);
        return true;
    }

    //TODO: error reporting, to allow user to distinguish empty directory from error condition.

    return false;
}

static bool isPackage(const QFileSystemMetaData &data, const QFileSystemEntry &entry)
{
    if (!data.isDirectory())
        return false;

    QFileInfo info(entry.filePath());
    QString suffix = info.suffix();

    if (suffix.length() > 0) {
        // First step: is the extension known ?
        CFStringRef extensionRef = QCFString::toCFStringRef(suffix);
        CFStringRef uniformTypeIdentifier = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, extensionRef, NULL);
        if (UTTypeConformsTo(uniformTypeIdentifier, kUTTypeBundle))
            return true;

        // Second step: check if an application knows the package type
        CFStringRef path = QCFString::toCFStringRef(entry.filePath());
        QCFType<CFURLRef> url = CFURLCreateWithFileSystemPath(0, path, kCFURLPOSIXPathStyle, true);

        UInt32 type, creator;
        // Well created packages have the PkgInfo file
        if (CFBundleGetPackageInfoInDirectory(url, &type, &creator))
            return true;

        // Find if an application other than Finder claims to know how to handle the package
        QCFType<CFURLRef> application;
        LSGetApplicationForURL(url,
                               kLSRolesEditor|kLSRolesViewer|kLSRolesViewer,
                               NULL,
                               &application);

        if (application) {
            QCFType<CFBundleRef> bundle = CFBundleCreate(kCFAllocatorDefault, application);
            CFStringRef identifier = CFBundleGetIdentifier(bundle);
            QString applicationId = QCFString::toQString(identifier);
            if (applicationId != QLatin1String("com.apple.finder"))
                return true;
        }
    }

    // Third step: check if the directory has the package bit set
    FSRef packageRef;
    FSPathMakeRef((UInt8 *)entry.nativeFilePath().constData(), &packageRef, NULL);

    FSCatalogInfo catalogInfo;
    FSGetCatalogInfo(&packageRef,
                     kFSCatInfoFinderInfo,
                     &catalogInfo,
                     NULL,
                     NULL,
                     NULL);

    FolderInfo *folderInfo = reinterpret_cast<FolderInfo *>(catalogInfo.finderInfo);
    return folderInfo->finderFlags & kHasBundle;
}

//static
bool QFileSystemEngine::fillMetaData(int fd, QFileSystemMetaData &data)
{
    data.entryFlags &= ~QFileSystemMetaData::PosixStatFlags;
    data.knownFlagsMask |= QFileSystemMetaData::PosixStatFlags;

    QT_STATBUF statBuffer;
    if (QT_FSTAT(fd, &statBuffer) == 0) {
        data.fillFromStatBuf(statBuffer);
        return true;
    }

    return false;
}

//static
bool QFileSystemEngine::fillMetaData(const QFileSystemEntry &entry, QFileSystemMetaData &data, QFileSystemMetaData::MetaDataFlags what)
{
    if (what & QFileSystemMetaData::SymbianTEntryFlags) {
        RFs& fs(qt_s60GetRFs());
        TInt err;
        QFileSystemEntry absentry(absoluteName(entry));
        if (entry.isEmpty()) {
            err = KErrNotFound;
        } else if (absentry.isRoot()) {
            //Root directories don't have an entry, and Entry() returns KErrBadName.
            //Therefore get information about the volume instead.
            TInt drive;
            err = RFs::CharToDrive(TChar(absentry.nativeFilePath().at(0).unicode()), drive);
            if (!err) {
                TVolumeInfo info;
                err = fs.Volume(info, drive);
                if (!err)
                    data.fillFromVolumeInfo(info);
            }
        } else {
            TEntry ent;
            err = fs.Entry(qt_QString2TPtrC(absentry.nativeFilePath()), ent);
            if (!err)
                data.fillFromTEntry(ent);
        }
        if (err) {
            data.size_ = 0;
            data.modificationTime_ = TTime(0);
            data.entryFlags &= ~(QFileSystemMetaData::SymbianTEntryFlags);
        }
        //files in /sys/bin on any drive are executable, even though we don't normally have permission to check whether they exist or not
        if(absentry.filePath().midRef(1,10).compare(QLatin1String(":/sys/bin/"), Qt::CaseInsensitive) == 0)
            data.entryFlags |= QFileSystemMetaData::ExecutePermissions;
    }
    return data.hasFlags(what);
}

static bool isPackage(const QFileSystemMetaData &data, const QFileSystemEntry &entry)
{
    if (!data.isDirectory())
        return false;

    QFileInfo info(entry.filePath());
    QString suffix = info.suffix();

    if (suffix.length() > 0) {
        // First step: is the extension known ?
        QCFType<CFStringRef> extensionRef = QCFString::toCFStringRef(suffix);
        QCFType<CFStringRef> uniformTypeIdentifier = UTTypeCreatePreferredIdentifierForTag(kUTTagClassFilenameExtension, extensionRef, NULL);
        if (UTTypeConformsTo(uniformTypeIdentifier, kUTTypeBundle))
            return true;

        // Second step: check if an application knows the package type
        QCFType<CFStringRef> path = QCFString::toCFStringRef(entry.filePath());
        QCFType<CFURLRef> url = CFURLCreateWithFileSystemPath(0, path, kCFURLPOSIXPathStyle, true);

        UInt32 type, creator;
        // Well created packages have the PkgInfo file
        if (CFBundleGetPackageInfoInDirectory(url, &type, &creator))
            return true;

#ifdef Q_OS_OSX
        // Find if an application other than Finder claims to know how to handle the package
        QCFType<CFURLRef> application;
        LSGetApplicationForURL(url,
                               kLSRolesEditor|kLSRolesViewer|kLSRolesViewer,
                               NULL,
                               &application);

        if (application) {
            QCFType<CFBundleRef> bundle = CFBundleCreate(kCFAllocatorDefault, application);
            CFStringRef identifier = CFBundleGetIdentifier(bundle);
            QString applicationId = QCFString::toQString(identifier);
            if (applicationId != QLatin1String("com.apple.finder"))
                return true;
        }
#endif
    }

    // Third step: check if the directory has the package bit set
    return hasResourcePropertyFlag(data, entry, kCFURLIsPackageKey);
}

//static
QFileSystemEntry QFileSystemEngine::canonicalName(const QFileSystemEntry &entry, QFileSystemMetaData &data)
{
    if (entry.isEmpty() || entry.isRoot())
        return entry;

#if !defined(Q_OS_MAC) && !defined(Q_OS_QNX) && !defined(Q_OS_ANDROID) && !defined(Q_OS_HAIKU) && _POSIX_VERSION < 200809L
    // realpath(X,0) is not supported
    Q_UNUSED(data);
    return QFileSystemEntry(slowCanonicalized(absoluteName(entry).filePath()));
#else
    char *ret = 0;
# if defined(Q_OS_DARWIN)
    ret = (char*)malloc(PATH_MAX + 1);
    if (ret && realpath(entry.nativeFilePath().constData(), (char*)ret) == 0) {
        const int savedErrno = errno; // errno is checked below, and free() might change it
        free(ret);
        errno = savedErrno;
        ret = 0;
    }
# elif defined(Q_OS_ANDROID)
    // On some Android versions, realpath() will return a path even if it does not exist
    // To work around this, we check existence in advance.
    if (!data.hasFlags(QFileSystemMetaData::ExistsAttribute))
        fillMetaData(entry, data, QFileSystemMetaData::ExistsAttribute);

    if (!data.exists()) {
        ret = 0;
        errno = ENOENT;
    } else {
        ret = (char*)malloc(PATH_MAX + 1);
        if (realpath(entry.nativeFilePath().constData(), (char*)ret) == 0) {
            const int savedErrno = errno; // errno is checked below, and free() might change it
            free(ret);
            errno = savedErrno;
            ret = 0;
        }
    }

# else
#  if _POSIX_VERSION >= 200801L
    ret = realpath(entry.nativeFilePath().constData(), (char*)0);
#  else
    ret = (char*)malloc(PATH_MAX + 1);
    if (realpath(entry.nativeFilePath().constData(), (char*)ret) == 0) {
        const int savedErrno = errno; // errno is checked below, and free() might change it
        free(ret);
        errno = savedErrno;
        ret = 0;
    }
#  endif
# endif
    if (ret) {
        data.knownFlagsMask |= QFileSystemMetaData::ExistsAttribute;
        data.entryFlags |= QFileSystemMetaData::ExistsAttribute;
        QString canonicalPath = QDir::cleanPath(QString::fromLocal8Bit(ret));
        free(ret);
        return QFileSystemEntry(canonicalPath);
    } else if (errno == ENOENT) { // file doesn't exist
        data.knownFlagsMask |= QFileSystemMetaData::ExistsAttribute;
        data.entryFlags &= ~(QFileSystemMetaData::ExistsAttribute);
        return QFileSystemEntry();
    }
    return entry;
#endif
}

//static
QFileSystemEntry QFileSystemEngine::getLinkTarget(const QFileSystemEntry &link, QFileSystemMetaData &data)
{
#if defined(__GLIBC__) && !defined(PATH_MAX)
#define PATH_CHUNK_SIZE 256
    char *s = 0;
    int len = -1;
    int size = PATH_CHUNK_SIZE;

    while (1) {
        s = (char *) ::realloc(s, size);
        Q_CHECK_PTR(s);
        len = ::readlink(link.nativeFilePath().constData(), s, size);
        if (len < 0) {
            ::free(s);
            break;
        }
        if (len < size) {
            break;
        }
        size *= 2;
    }
#else
    char s[PATH_MAX+1];
    int len = readlink(link.nativeFilePath().constData(), s, PATH_MAX);
#endif
    if (len > 0) {
        QString ret;
        if (!data.hasFlags(QFileSystemMetaData::DirectoryType))
            fillMetaData(link, data, QFileSystemMetaData::DirectoryType);
        if (data.isDirectory() && s[0] != '/') {
            QDir parent(link.filePath());
            parent.cdUp();
            ret = parent.path();
            if (!ret.isEmpty() && !ret.endsWith(QLatin1Char('/')))
                ret += QLatin1Char('/');
        }
        s[len] = '\0';
        ret += QFile::decodeName(QByteArray(s));
#if defined(__GLIBC__) && !defined(PATH_MAX)
        ::free(s);
#endif

        if (!ret.startsWith(QLatin1Char('/'))) {
            if (link.filePath().startsWith(QLatin1Char('/'))) {
                ret.prepend(link.filePath().left(link.filePath().lastIndexOf(QLatin1Char('/')))
                            + QLatin1Char('/'));
            } else {
                ret.prepend(QDir::currentPath() + QLatin1Char('/'));
            }
        }
        ret = QDir::cleanPath(ret);
        if (ret.size() > 1 && ret.endsWith(QLatin1Char('/')))
            ret.chop(1);
        return QFileSystemEntry(ret);
    }
#if !defined(QWS) && !defined(Q_WS_QPA) && defined(Q_OS_MAC)
    {
        FSRef fref;
        if (FSPathMakeRef((const UInt8 *)QFile::encodeName(QDir::cleanPath(link.filePath())).data(), &fref, 0) == noErr) {
            // TODO get the meta data info from the QFileSystemMetaData object
            Boolean isAlias, isFolder;
            if (FSResolveAliasFile(&fref, true, &isFolder, &isAlias) == noErr && isAlias) {
                AliasHandle alias;
                if (FSNewAlias(0, &fref, &alias) == noErr && alias) {
                    QCFString cfstr;
                    if (FSCopyAliasInfo(alias, 0, 0, &cfstr, 0, 0) == noErr)
                        return QFileSystemEntry(QCFString::toQString(cfstr));
                }
            }
        }
    }
#endif
    return QFileSystemEntry();
}

//static
bool QFileSystemEngine::fillMetaData(const QFileSystemEntry &entry, QFileSystemMetaData &data,
        QFileSystemMetaData::MetaDataFlags what)
{
#if defined(Q_OS_MACX)
    if (what & QFileSystemMetaData::BundleType) {
        if (!data.hasFlags(QFileSystemMetaData::DirectoryType))
            what |= QFileSystemMetaData::DirectoryType;
    }
    if (what & QFileSystemMetaData::HiddenAttribute) {
        // Mac OS >= 10.5: st_flags & UF_HIDDEN
        what |= QFileSystemMetaData::PosixStatFlags;
    }
#endif // defined(Q_OS_MACX)

    if (what & QFileSystemMetaData::PosixStatFlags)
        what |= QFileSystemMetaData::PosixStatFlags;

    if (what & QFileSystemMetaData::ExistsAttribute) {
        //  FIXME:  Would other queries being performed provide this bit?
        what |= QFileSystemMetaData::PosixStatFlags;
    }

    data.entryFlags &= ~what;

    const char * nativeFilePath;
    int nativeFilePathLength;
    {
        const QByteArray &path = entry.nativeFilePath();
        nativeFilePath = path.constData();
        nativeFilePathLength = path.size();
        Q_UNUSED(nativeFilePathLength);
    }

    bool entryExists = true; // innocent until proven otherwise

    QT_STATBUF statBuffer;
    bool statBufferValid = false;
    if (what & QFileSystemMetaData::LinkType) {
        if (QT_LSTAT(nativeFilePath, &statBuffer) == 0) {
            if (S_ISLNK(statBuffer.st_mode)) {
                data.entryFlags |= QFileSystemMetaData::LinkType;
            } else {
                statBufferValid = true;
                data.entryFlags &= ~QFileSystemMetaData::PosixStatFlags;
            }
        } else {
            entryExists = false;
        }

        data.knownFlagsMask |= QFileSystemMetaData::LinkType;
    }

    if (statBufferValid || (what & QFileSystemMetaData::PosixStatFlags)) {
        if (entryExists && !statBufferValid)
            statBufferValid = (QT_STAT(nativeFilePath, &statBuffer) == 0);

        if (statBufferValid)
            data.fillFromStatBuf(statBuffer);
        else {
            entryExists = false;
            data.creationTime_ = 0;
            data.modificationTime_ = 0;
            data.accessTime_ = 0;
            data.size_ = 0;
            data.userId_ = (uint) -2;
            data.groupId_ = (uint) -2;
        }

        // reset the mask
        data.knownFlagsMask |= QFileSystemMetaData::PosixStatFlags
            | QFileSystemMetaData::ExistsAttribute;
    }

#if defined(Q_OS_MACX)
    if (what & QFileSystemMetaData::AliasType)
    {
        if (entryExists) {
            FSRef fref;
            if (FSPathMakeRef((const UInt8 *)nativeFilePath, &fref, NULL) == noErr) {
                Boolean isAlias, isFolder;
                if (FSIsAliasFile(&fref, &isAlias, &isFolder) == noErr) {
                    if (isAlias)
                        data.entryFlags |= QFileSystemMetaData::AliasType;
                }
            }
        }
        data.knownFlagsMask |= QFileSystemMetaData::AliasType;
    }
#endif

    if (what & QFileSystemMetaData::UserPermissions) {
        // calculate user permissions

        if (entryExists) {
            if (what & QFileSystemMetaData::UserReadPermission) {
                if (QT_ACCESS(nativeFilePath, R_OK) == 0)
                    data.entryFlags |= QFileSystemMetaData::UserReadPermission;
            }
            if (what & QFileSystemMetaData::UserWritePermission) {
//.........这里部分代码省略.........