qresource.cpp

QT 开发环境里面一个很重要的文件

        //setup the data now
        int offset = 0;

        //magic number
        if(unmapPointer[offset+0] != 'q' || unmapPointer[offset+1] != 'r' ||
           unmapPointer[offset+2] != 'e' || unmapPointer[offset+3] != 's') {
            return false;
        }
        offset += 4;

        const int version = (unmapPointer[offset+0] << 24) + (unmapPointer[offset+1] << 16) +
                         (unmapPointer[offset+2] << 8) + (unmapPointer[offset+3] << 0);
        offset += 4;

        const int tree_offset = (unmapPointer[offset+0] << 24) + (unmapPointer[offset+1] << 16) +
                                (unmapPointer[offset+2] << 8) + (unmapPointer[offset+3] << 0);
        offset += 4;

        const int data_offset = (unmapPointer[offset+0] << 24) + (unmapPointer[offset+1] << 16) +
                                (unmapPointer[offset+2] << 8) + (unmapPointer[offset+3] << 0);
        offset += 4;

        const int name_offset = (unmapPointer[offset+0] << 24) + (unmapPointer[offset+1] << 16) +
                                (unmapPointer[offset+2] << 8) + (unmapPointer[offset+3] << 0);
        offset += 4;

        if(version == 0x01) {
            setSource(unmapPointer+tree_offset, unmapPointer+name_offset, unmapPointer+data_offset);
            return true;
        }
        return false;
    }
};


static QString qt_resource_fixResourceRoot(QString r) {
    if(!r.isEmpty()) {
        if(r.startsWith(QLatin1Char(':')))
            r = r.mid(1);
        if(!r.isEmpty())
            r = QDir::cleanPath(r);
    }
    return r;
}


/*!
   \fn bool QResource::registerResource(const QString &rccFileName, const QString &mapRoot)

   Registers the resource with the given \a rccFileName at the location in the
   resource tree specified by \a mapRoot, and returns true if the file is
   successfully opened; otherwise returns false.

   \sa unregisterResource()
*/

bool
QResource::registerResource(const QString &rccFilename, const QString &resourceRoot)
{
    QString r = qt_resource_fixResourceRoot(resourceRoot);
    if(!r.isEmpty() && r[0] != QLatin1Char('/')) {
        qWarning("QDir::registerResource: Registering a resource [%s] must be rooted in an absolute path (start with /) [%s]",
                 rccFilename.toLocal8Bit().data(), resourceRoot.toLocal8Bit().data());
        return false;
    }

    QDynamicResourceRoot *root = new QDynamicResourceRoot(r);
    if(root->registerSelf(rccFilename)) {
        root->ref.ref();
        QMutexLocker lock(resourceMutex());
        resourceList()->append(root);
        return true;
    }
    delete root;
    return false;
}

/*!
  \fn bool QResource::unregisterResource(const QString &rccFileName, const QString &mapRoot)

  Unregisters the resource with the given \a rccFileName at the location in the
  resource tree specified by \a mapRoot, and returns true if the resource is
  successfully unloaded; otherwise returns false.

  \sa registerResource()
*/

bool
QResource::unregisterResource(const QString &rccFilename, const QString &resourceRoot)
{
    QString r = qt_resource_fixResourceRoot(resourceRoot);

    QMutexLocker lock(resourceMutex());
    ResourceList *list = resourceList();
    for(int i = 0; i < list->size(); ++i) {
        QResourceRoot *res = list->at(i);
        if(res->isDynamicRoot()) {
	    QDynamicResourceRoot *root = reinterpret_cast<QDynamicResourceRoot*>(res);
	    if(root->mappingFile() == rccFilename && root->mappingRoot() == r) {
                resourceList()->removeAt(i);
                if(!root->ref.deref())
                    delete root;
		return true;
            }
	}
    }
    return false;
}


//file type handler
class QResourceFileEngineHandler : public QAbstractFileEngineHandler
{
public:
    QResourceFileEngineHandler() { }
    ~QResourceFileEngineHandler() { }
    QAbstractFileEngine *create(const QString &path) const;
};
QAbstractFileEngine *QResourceFileEngineHandler::create(const QString &path) const
{
    if (path.size() > 0 && path.startsWith(QLatin1Char(':')))
        return new QResourceFileEngine(path);
    return 0;
}

//resource engine
class QResourceFileEnginePrivate : public QAbstractFileEnginePrivate
{
protected:
    Q_DECLARE_PUBLIC(QResourceFileEngine)
private:
    qint64 offset;
    QResource resource;
    QByteArray uncompressed;
protected:
    QResourceFileEnginePrivate() : offset(0) { }
};

bool QResourceFileEngine::mkdir(const QString &, bool) const
{
    return false;
}

bool QResourceFileEngine::rmdir(const QString &, bool) const
{
    return false;
}

bool QResourceFileEngine::setSize(qint64)
{
    return false;
}

QStringList QResourceFileEngine::entryList(QDir::Filters filters, const QStringList &filterNames) const
{
    Q_D(const QResourceFileEngine);

    const bool doDirs     = (filters & QDir::Dirs) != 0;
    const bool doFiles    = (filters & QDir::Files) != 0;
    const bool doReadable = (filters & QDir::Readable) != 0;

    QStringList ret;
    if((!doDirs && !doFiles) || ((filters & QDir::PermissionMask) && !doReadable))
        return ret;
    if(!d->resource.isValid() || !d->resource.isDir())
        return ret; // cannot read the "directory"

    QStringList entries = d->resource.children();
    for(int i = 0; i < entries.size(); i++) {
        QResource entry(d->resource.fileName() + QLatin1String("/") + entries[i]);
#ifndef QT_NO_REGEXP
        if(!(filters & QDir::AllDirs && entry.isDir())) {
            bool matched = false;
            for(QStringList::ConstIterator sit = filterNames.begin(); sit != filterNames.end(); ++sit) {
                QRegExp rx(*sit,
                           (filters & QDir::CaseSensitive) ? Qt::CaseSensitive : Qt::CaseInsensitive,
                           QRegExp::Wildcard);
                if (rx.exactMatch(entries[i])) {
                    matched = true;
                    break;
                }
            }
            if(!matched)
                continue;
        }
#endif
        if  ((doDirs && entry.isDir()) ||
             (doFiles && !entry.isDir()))
            ret.append(entries[i]);
    }
    return ret;
}

bool QResourceFileEngine::caseSensitive() const
{
    return true;
}

QResourceFileEngine::QResourceFileEngine(const QString &file) :
    QAbstractFileEngine(*new QResourceFileEnginePrivate)
{
    Q_D(QResourceFileEngine);
    d->resource.setFileName(file);
    if(d->resource.isCompressed() && d->resource.size()) {
#ifndef QT_NO_COMPRESS
        d->uncompressed = qUncompress(d->resource.data(), d->resource.size());
#else
        Q_ASSERT("QResourceFileEngine::open: Qt built without support for compression");
#endif
    }
}

QResourceFileEngine::~QResourceFileEngine()
{
}

void QResourceFileEngine::setFileName(const QString &file)
{
    Q_D(QResourceFileEngine);
    d->resource.setFileName(file);
}

bool QResourceFileEngine::open(QIODevice::OpenMode flags)
{
    Q_D(QResourceFileEngine);
    if (d->resource.fileName().isEmpty()) {
        qWarning("QResourceFileEngine::open: Missing file name");
        return false;
    }
    if(flags & QIODevice::WriteOnly)
        return false;
    if(!d->resource.isValid())
       return false;
    return true;
}

bool QResourceFileEngine::close()
{
    Q_D(QResourceFileEngine);
    d->offset = 0;
    d->uncompressed.clear();
    return true;
}

bool QResourceFileEngine::flush()
{
    return false;
}

qint64 QResourceFileEngine::read(char *data, qint64 len)
{
    Q_D(QResourceFileEngine);
    if(len > size()-d->offset)
        len = size()-d->offset;
    if(len <= 0)
        return 0;
    if(d->resource.isCompressed())
        memcpy(data, d->uncompressed.constData()+d->offset, len);
    else
        memcpy(data, d->resource.data()+d->offset, len);
    d->offset += len;
    return len;
}

qint64 QResourceFileEngine::write(const char *, qint64)
{
    return -1;
}

bool QResourceFileEngine::remove()
{
    return false;
}

bool QResourceFileEngine::copy(const QString &)
{
    return false;
}

bool QResourceFileEngine::rename(const QString &)
{
    return false;
}

bool QResourceFileEngine::link(const QString &)
{
    return false;
}

qint64 QResourceFileEngine::size() const
{
    Q_D(const QResourceFileEngine);
    if(!d->resource.isValid())
        return 0;
    if(d->resource.isCompressed())
        return d->uncompressed.size();
    return d->resource.size();
}

qint64 QResourceFileEngine::pos() const
{
    Q_D(const QResourceFileEngine);
    return d->offset;
}

bool QResourceFileEngine::atEnd() const
{
    Q_D(const QResourceFileEngine);
    if(!d->resource.isValid())
        return true;
    return d->offset == size();
}

bool QResourceFileEngine::seek(qint64 pos)
{
    Q_D(QResourceFileEngine);
    if(!d->resource.isValid())
        return false;

    if(d->offset > size())
        return false;
    d->offset = pos;
    return true;
}

bool QResourceFileEngine::isSequential() const
{
    return false;
}

QAbstractFileEngine::FileFlags QResourceFileEngine::fileFlags(QAbstractFileEngine::FileFlags type) const
{
    Q_D(const QResourceFileEngine);
    QAbstractFileEngine::FileFlags ret = 0;
    if(!d->resource.isValid())
        return ret;

    if(type & PermsMask)
        ret |= QAbstractFileEngine::FileFlags(ReadOwnerPerm|ReadUserPerm|ReadGroupPerm|ReadOtherPerm);
    if(type & TypesMask) {
        if(d->resource.isDir())
            ret |= DirectoryType;
        else
            ret |= FileType;
    }
    if(type & FlagsMask) {
        ret |= ExistsFlag;
        if(d->resource.absoluteFilePath() == QLatin1String(":/"))
            ret |= RootFlag;
    }
    return ret;
}

bool QResourceFileEngine::setPermissions(uint)
{
    return false;
}

QString QResourceFileEngine::fileName(FileName file) const
{
    Q_D(const QResourceFileEngine);
    if(file == BaseName) {
	int slash = d->resource.fileName().lastIndexOf(QLatin1Char('/'));
	if (slash == -1)
	    return d->resource.fileName();
	return d->resource.fileName().mid(slash + 1);
    } else if(file == PathName || file == AbsolutePathName) {
        const QString path = (file == AbsolutePathName) ? d->resource.absoluteFilePath() : d->resource.fileName();
	const int slash = path.lastIndexOf(QLatin1Char('/'));
	if (slash != -1)
	    return path.left(slash);
    } else if(file == CanonicalName || file == CanonicalPathName) {
        const QString absoluteFilePath = d->resource.absoluteFilePath();
        if(file == CanonicalPathName) {
            const int slash = absoluteFilePath.lastIndexOf(QLatin1Char('/'));
            if (slash != -1)
                return absoluteFilePath.left(slash);
        }
        return absoluteFilePath;
    }
    return d->resource.fileName();
}

bool QResourceFileEngine::isRelativePath() const
{
    return false;
}

uint QResourceFileEngine::ownerId(FileOwner) const
{
    static const uint nobodyID = (uint) -2;
    return nobodyID;
}

QString QResourceFileEngine::owner(FileOwner) const
{
    return QString();
}

QDateTime QResourceFileEngine::fileTime(FileTime) const
{
    return QDateTime();
}

bool QResourceFileEngine::extension(Extension extension, const ExtensionOption *option, ExtensionReturn *output)
{
    Q_UNUSED(extension);
    Q_UNUSED(option);
    Q_UNUSED(output);
    return false;
}

bool QResourceFileEngine::supportsExtension(Extension extension) const
{
    Q_UNUSED(extension);
    return false;
}

//Initialization and cleanup
Q_GLOBAL_STATIC(QResourceFileEngineHandler, resource_file_handler)

static int qt_force_resource_init() { resource_file_handler(); return 1; }
Q_CORE_EXPORT void qInitResourceIO() { resource_file_handler(); }
static int qt_forced_resource_init = qt_force_resource_init();
Q_CONSTRUCTOR_FUNCTION(qt_force_resource_init)