# coding: utf-8
# /*##########################################################################
#
# Copyright (c) 2016 European Synchrotron Radiation Facility
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
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# ###########################################################################*/
"""
This module contains an :class:`AbstractDataFileDialog`.
"""

__authors__ = ["V. Valls"]
__license__ = "MIT"
__date__ = "05/03/2018"


import sys
import os
import logging
import numpy
import functools
import silx.io.url
from silx.gui import qt
from silx.gui.hdf5.Hdf5TreeModel import Hdf5TreeModel
from . import utils
from silx.third_party import six
from .FileTypeComboBox import FileTypeComboBox
try:
    import fabio
except ImportError:
    fabio = None


_logger = logging.getLogger(__name__)


class _IconProvider(object):

    FileDialogToParentDir = qt.QStyle.SP_CustomBase + 1

    FileDialogToParentFile = qt.QStyle.SP_CustomBase + 2

    def __init__(self):
        self.__iconFileDialogToParentDir = None
        self.__iconFileDialogToParentFile = None

    def _createIconToParent(self, standardPixmap):
        """

        FIXME: It have to be tested for some OS (arrow icon do not have always
        the same direction)
        """
        style = qt.QApplication.style()
        baseIcon = style.standardIcon(qt.QStyle.SP_FileDialogToParent)
        backgroundIcon = style.standardIcon(standardPixmap)
        icon = qt.QIcon()

        sizes = baseIcon.availableSizes()
        sizes = sorted(sizes, key=lambda s: s.height())
        sizes = filter(lambda s: s.height() < 100, sizes)
        sizes = list(sizes)
        if len(sizes) > 0:
            baseSize = sizes[-1]
        else:
            baseSize = baseIcon.availableSizes()[0]
        size = qt.QSize(baseSize.width(), baseSize.height() * 3 // 2)

        modes = [qt.QIcon.Normal, qt.QIcon.Disabled]
        for mode in modes:
            pixmap = qt.QPixmap(size)
            pixmap.fill(qt.Qt.transparent)
            painter = qt.QPainter(pixmap)
            painter.drawPixmap(0, 0, backgroundIcon.pixmap(baseSize, mode=mode))
            painter.drawPixmap(0, size.height() // 3, baseIcon.pixmap(baseSize, mode=mode))
            painter.end()
            icon.addPixmap(pixmap, mode=mode)

        return icon

    def getFileDialogToParentDir(self):
        if self.__iconFileDialogToParentDir is None:
            self.__iconFileDialogToParentDir = self._createIconToParent(qt.QStyle.SP_DirIcon)
        return self.__iconFileDialogToParentDir

    def getFileDialogToParentFile(self):
        if self.__iconFileDialogToParentFile is None:
            self.__iconFileDialogToParentFile = self._createIconToParent(qt.QStyle.SP_FileIcon)
        return self.__iconFileDialogToParentFile

    def icon(self, kind):
        if kind == self.FileDialogToParentDir:
            return self.getFileDialogToParentDir()
        elif kind == self.FileDialogToParentFile:
            return self.getFileDialogToParentFile()
        else:
            style = qt.QApplication.style()
            icon = style.standardIcon(kind)
            return icon


class _SideBar(qt.QListView):
    """Sidebar containing shortcuts for common directories"""

    def __init__(self, parent=None):
        super(_SideBar, self).__init__(parent)
        self.__iconProvider = qt.QFileIconProvider()
        self.setUniformItemSizes(True)
        model = qt.QStandardItemModel(self)
        self.setModel(model)
        self._initModel()
        self.setEditTriggers(qt.QAbstractItemView.NoEditTriggers)

    def iconProvider(self):
        return self.__iconProvider

    def _initModel(self):
        urls = self._getDefaultUrls()
        self.setUrls(urls)

    def _getDefaultUrls(self):
        """Returns the default shortcuts.

        It uses the default QFileDialog shortcuts if it is possible, else
        provides a link to the computer's root and the user's home.

        :rtype: List[str]
        """
        urls = []
        if qt.qVersion().startswith("5.") and sys.platform in ["linux", "linux2"]:
            # Avoid segfault on PyQt5 + gtk
            _logger.debug("Skip default sidebar URLs (avoid PyQt5 segfault)")
            pass
        elif qt.qVersion().startswith("4.") and sys.platform in ["win32"]:
            # Avoid 5min of locked GUI relative to network driver
            _logger.debug("Skip default sidebar URLs (avoid lock when using network drivers)")
        else:
            # Get default shortcut
            # There is no other way
            d = qt.QFileDialog(self)
            # Needed to be able to reach the sidebar urls
            d.setOption(qt.QFileDialog.DontUseNativeDialog, True)
            urls = d.sidebarUrls()
            d.deleteLater()
            d = None

        if len(urls) == 0:
            urls.append(qt.QUrl("file://"))
            urls.append(qt.QUrl.fromLocalFile(qt.QDir.homePath()))

        return urls

    def setSelectedPath(self, path):
        selected = None
        model = self.model()
        for i in range(model.rowCount()):
            index = model.index(i, 0)
            url = model.data(index, qt.Qt.UserRole)
            urlPath = url.toLocalFile()
            if path == urlPath:
                selected = index

        selectionModel = self.selectionModel()
        if selected is not None:
            selectionModel.setCurrentIndex(selected, qt.QItemSelectionModel.ClearAndSelect)
        else:
            selectionModel.clear()

    def setUrls(self, urls):
        model = self.model()
        model.clear()

        names = {}
        names[qt.QDir.rootPath()] = "Computer"
        names[qt.QDir.homePath()] = "Home"

        style = qt.QApplication.style()
        iconProvider = self.iconProvider()
        for url in urls:
            path = url.toLocalFile()
            if path == "":
                if sys.platform != "win32":
                    url = qt.QUrl(qt.QDir.rootPath())
                name = "Computer"
                icon = style.standardIcon(qt.QStyle.SP_ComputerIcon)
            else:
                fileInfo = qt.QFileInfo(path)
                name = names.get(path, fileInfo.fileName())
                icon = iconProvider.icon(fileInfo)

            if icon.isNull():
                icon = style.standardIcon(qt.QStyle.SP_MessageBoxCritical)

            item = qt.QStandardItem()
            item.setText(name)
            item.setIcon(icon)
            item.setData(url, role=qt.Qt.UserRole)
            model.appendRow(item)

    def urls(self):
        result = []
        model = self.model()
        for i in range(model.rowCount()):
            index = model.index(i, 0)
            url = model.data(index, qt.Qt.UserRole)
            result.append(url)
        return result

    def sizeHint(self):
        index = self.model().index(0, 0)
        return self.sizeHintForIndex(index) + qt.QSize(2 * self.frameWidth(), 2 * self.frameWidth())


class _Browser(qt.QStackedWidget):

    activated = qt.Signal(qt.QModelIndex)
    selected = qt.Signal(qt.QModelIndex)
    rootIndexChanged = qt.Signal(qt.QModelIndex)

    def __init__(self, parent, listView, detailView):
        qt.QStackedWidget.__init__(self, parent)
        self.__listView = listView
        self.__detailView = detailView
        self.insertWidget(0, self.__listView)
        self.insertWidget(1, self.__detailView)

        self.__listView.activated.connect(self.__emitActivated)
        self.__detailView.activated.connect(self.__emitActivated)

    def __emitActivated(self, index):
        self.activated.emit(index)

    def __emitSelected(self, selected, deselected):
        index = self.selectedIndex()
        if index is not None:
            self.selected.emit(index)

    def selectedIndex(self):
        if self.currentIndex() == 0:
            selectionModel = self.__listView.selectionModel()
        else:
            selectionModel = self.__detailView.selectionModel()

        if selectionModel is None:
            return None

        indexes = selectionModel.selectedIndexes()
        # Filter non-main columns
        indexes = [i for i in indexes if i.column() == 0]
        if len(indexes) == 1:
            index = indexes[0]
            return index
        return None

    def model(self):
        """Returns the current model."""
        if self.currentIndex() == 0:
            return self.__listView.model()
        else:
            return self.__detailView.model()

    def selectIndex(self, index):
        if self.currentIndex() == 0:
            selectionModel = self.__listView.selectionModel()
        else:
            selectionModel = self.__detailView.selectionModel()
        if selectionModel is None:
            return
        selectionModel.setCurrentIndex(index, qt.QItemSelectionModel.ClearAndSelect)

    def viewMode(self):
        """Returns the current view mode.

        :rtype: qt.QFileDialog.ViewMode
        """
        if self.currentIndex() == 0:
            return qt.QFileDialog.List
        elif self.currentIndex() == 1:
            return qt.QFileDialog.Detail
        else:
            assert(False)

    def setViewMode(self, mode):
        """Set the current view mode.

        :param qt.QFileDialog.ViewMode mode: The new view mode
        """
        if mode == qt.QFileDialog.Detail:
            self.showDetails()
        elif mode == qt.QFileDialog.List:
            self.showList()
        else:
            assert(False)

    def showList(self):
        self.__listView.show()
        self.__detailView.hide()
        self.setCurrentIndex(0)

    def showDetails(self):
        self.__listView.hide()
        self.__detailView.show()
        self.setCurrentIndex(1)
        self.__detailView.updateGeometry()

    def clear(self):
        self.__listView.setRootIndex(qt.QModelIndex())
        self.__detailView.setRootIndex(qt.QModelIndex())
        selectionModel = self.__listView.selectionModel()
        if selectionModel is not None:
            selectionModel.selectionChanged.disconnect()
            selectionModel.clear()
        selectionModel = self.__detailView.selectionModel()
        if selectionModel is not None:
            selectionModel.selectionChanged.disconnect()
            selectionModel.clear()
        self.__listView.setModel(None)
        self.__detailView.setModel(None)

    def setRootIndex(self, index, model=None):
        """Sets the root item to the item at the given index.
        """
        rootIndex = self.__listView.rootIndex()
        newModel = model or index.model()
        assert(newModel is not None)

        if rootIndex is None or rootIndex.model() is not newModel:
            # update the model
            selectionModel = self.__listView.selectionModel()
            if selectionModel is not None:
                selectionModel.selectionChanged.disconnect()
                selectionModel.clear()
            selectionModel = self.__detailView.selectionModel()
            if selectionModel is not None:
                selectionModel.selectionChanged.disconnect()
                selectionModel.clear()
            pIndex = qt.QPersistentModelIndex(index)
            self.__listView.setModel(newModel)
            # changing the model of the tree view change the index mapping
            # that is why we are using a persistance model index
            self.__detailView.setModel(newModel)
            index = newModel.index(pIndex.row(), pIndex.column(), pIndex.parent())
            selectionModel = self.__listView.selectionModel()
            selectionModel.selectionChanged.connect(self.__emitSelected)
            selectionModel = self.__detailView.selectionModel()
            selectionModel.selectionChanged.connect(self.__emitSelected)

        self.__listView.setRootIndex(index)
        self.__detailView.setRootIndex(index)
        self.rootIndexChanged.emit(index)

    def rootIndex(self):
        """Returns the model index of the model's root item. The root item is
        the parent item to the view's toplevel items. The root can be invalid.
        """
        return self.__listView.rootIndex()

    __serialVersion = 1
    """Store the current version of the serialized data"""

    def visualRect(self, index):
        """Returns the rectangle on the viewport occupied by the item at index.

        :param qt.QModelIndex index: An index
        :rtype: QRect
        """
        if self.currentIndex() == 0:
            return self.__listView.visualRect(index)
        else:
            return self.__detailView.visualRect(index)

    def viewport(self):
        """Returns the viewport widget.

        :param qt.QModelIndex index: An index
        :rtype: QRect
        """
        if self.currentIndex() == 0:
            return self.__listView.viewport()
        else:
            return self.__detailView.viewport()

    def restoreState(self, state):
        """Restores the dialogs's layout, history and current directory to the
        state specified.

        :param qt.QByeArray state: Stream containing the new state
        :rtype: bool
        """
        stream = qt.QDataStream(state, qt.QIODevice.ReadOnly)

        nameId = stream.readQString()
        if nameId != "Browser":
            _logger.warning("Stored state contains an invalid name id. Browser restoration cancelled.")
            return False

        version = stream.readInt32()
        if version != self.__serialVersion:
            _logger.warning("Stored state contains an invalid version. Browser restoration cancelled.")
            return False

        headerData = stream.readQVariant()
        self.__detailView.header().restoreState(headerData)

        viewMode = stream.readInt32()
        self.setViewMode(viewMode)
        return True

    def saveState(self):
        """Saves the state of the dialog's layout.

        :rtype: qt.QByteArray
        """
        data = qt.QByteArray()
        stream = qt.QDataStream(data, qt.QIODevice.WriteOnly)

        nameId = u"Browser"
        stream.writeQString(nameId)
        stream.writeInt32(self.__serialVersion)
        stream.writeQVariant(self.__detailView.header().saveState())
        stream.writeInt32(self.viewMode())

        return data


class _FabioData(object):

    def __init__(self, fabioFile):
        self.__fabioFile = fabioFile

    @property
    def dtype(self):
        # Let say it is a valid type
        return numpy.dtype("float")

    @property
    def shape(self):
        if self.__fabioFile.nframes == 0:
            return None
        return [self.__fabioFile.nframes, slice(None), slice(None)]

    def __getitem__(self, selector):
        if isinstance(selector, tuple) and len(selector) == 1:
            selector = selector[0]

        if isinstance(selector, six.integer_types):
            if 0 <= selector < self.__fabioFile.nframes:
                if self.__fabioFile.nframes == 1:
                    return self.__fabioFile.data
                else:
                    frame = self.__fabioFile.getframe(selector)
                    return frame.data
            else:
                raise ValueError("Invalid selector %s" % selector)
        else:
            raise TypeError("Unsupported selector type %s" % type(selector))


class _PathEdit(qt.QLineEdit):
    pass


class _CatchResizeEvent(qt.QObject):

    resized = qt.Signal(qt.QResizeEvent)

    def __init__(self, parent, target):
        super(_CatchResizeEvent, self).__init__(parent)
        self.__target = target
        self.__target_oldResizeEvent = self.__target.resizeEvent
        self.__target.resizeEvent = self.__resizeEvent

    def __resizeEvent(self, event):
        result = self.__target_oldResizeEvent(event)
        self.resized.emit(event)
        return result


class AbstractDataFileDialog(qt.QDialog):
    """The `AbstractFileDialog` provides a generic GUI to create a custom dialog
    allowing to access to file resources like HDF5 files or HDF5 datasets.

    .. image:: img/abstractdatafiledialog.png

    The dialog contains:

    - Shortcuts: It provides few links to have a fast access of browsing
        locations.
    - Browser: It provides a display to browse throw the file system and inside
        HDF5 files or fabio files. A file format selector is provided.
    - URL: Display the URL available to reach the data using
        :meth:`silx.io.get_data`, :meth:`silx.io.open`.
    - Data selector: A widget to apply a sub selection of the browsed dataset.
        This widget can be provided, else nothing will be used.
    - Data preview: A widget to preview the selected data, which is the result
        of the filter from the data selector.
        This widget can be provided, else nothing will be used.
    - Preview's toolbar: Provides tools used to custom data preview or data
        selector.
        This widget can be provided, else nothing will be used.
    - Buttons to validate the dialog
    """

    _defaultIconProvider = None
    """Lazy loaded default icon provider"""

    def __init__(self, parent=None):
        super(AbstractDataFileDialog, self).__init__(parent)
        self._init()

    def _init(self):
        self.setWindowTitle("Open")

        self.__directory = None
        self.__directoryLoadedFilter = None
        self.__errorWhileLoadingFile = None
        self.__selectedFile = None
        self.__selectedData = None
        self.__currentHistory = []
        """Store history of URLs, last index one is the latest one"""
        self.__currentHistoryLocation = -1
        """Store the location in the history. Bigger is older"""

        self.__processing = 0
        """Number of asynchronous processing tasks"""
        self.__h5 = None
        self.__fabio = None

        if qt.qVersion() < "5.0":
            # On Qt4 it is needed to provide a safe file system model
            _logger.debug("Uses SafeFileSystemModel")
            from .SafeFileSystemModel import SafeFileSystemModel
            self.__fileModel = SafeFileSystemModel(self)
        else:
            # On Qt5 a safe icon provider is still needed to avoid freeze
            _logger.debug("Uses default QFileSystemModel with a SafeFileIconProvider")
            self.__fileModel = qt.QFileSystemModel(self)
            from .SafeFileIconProvider import SafeFileIconProvider
            iconProvider = SafeFileIconProvider()
            self.__fileModel.setIconProvider(iconProvider)

        # The common file dialog filter only on Mac OS X
        self.__fileModel.setNameFilterDisables(sys.platform == "darwin")
        self.__fileModel.setReadOnly(True)
        self.__fileModel.directoryLoaded.connect(self.__directoryLoaded)

        self.__dataModel = Hdf5TreeModel(self)

        self.__createWidgets()
        self.__initLayout()
        self.__showAsListView()

        path = os.getcwd()
        self.__fileModel_setRootPath(path)

        self.__clearData()
        self.__updatePath()

        # Update the file model filter
        self.__fileTypeCombo.setCurrentIndex(0)
        self.__filterSelected(0)

        self.__openedFiles = []
        """Store the list of files opened by the model itself."""
        # FIXME: It should be managed one by one by Hdf5Item itself

        # It is not possible to override the QObject destructor nor
        # to access to the content of the Python object with the `destroyed`
        # signal cause the Python method was already removed with the QWidget,
        # while the QObject still exists.
        # We use a static method plus explicit references to objects to
        # release. The callback do not use any ref to self.
        onDestroy = functools.partial(self._closeFileList, self.__openedFiles)
        self.destroyed.connect(onDestroy)

    @staticmethod
    def _closeFileList(fileList):
        """Static method to close explicit references to internal objects."""
        _logger.debug("Clear AbstractDataFileDialog")
        for obj in fileList:
            _logger.debug("Close file %s", obj.filename)
            obj.close()
        fileList[:] = []

    def done(self, result):
        self._clear()
        super(AbstractDataFileDialog, self).done(result)

    def _clear(self):
        """Explicit method to clear data stored in the dialog.
        After this call it is not anymore possible to use the widget.

        This method is triggered by the destruction of the object and the
        QDialog :meth:`done`. Then it can be triggered more than once.
        """
        _logger.debug("Clear dialog")
        self.__errorWhileLoadingFile = None
        self.__clearData()
        if self.__fileModel is not None:
            # Cache the directory before cleaning the model
            self.__directory = self.directory()
        self.__browser.clear()
        self.__closeFile()
        self.__fileModel = None
        self.__dataModel = None

    def hasPendingEvents(self):
        """Returns true if the dialog have asynchronous tasks working on the
        background."""
        return self.__processing > 0

    # User interface

    def __createWidgets(self):
        self.__sidebar = self._createSideBar()
        if self.__sidebar is not None:
            sideBarModel = self.__sidebar.selectionModel()
            sideBarModel.selectionChanged.connect(self.__shortcutSelected)
            self.__sidebar.setSelectionMode(qt.QAbstractItemView.SingleSelection)

        listView = qt.QListView(self)
        listView.setSelectionBehavior(qt.QAbstractItemView.SelectRows)
        listView.setSelectionMode(qt.QAbstractItemView.SingleSelection)
        listView.setResizeMode(qt.QListView.Adjust)
        listView.setWrapping(True)
        listView.setEditTriggers(qt.QAbstractItemView.NoEditTriggers)
        listView.setContextMenuPolicy(qt.Qt.CustomContextMenu)
        utils.patchToConsumeReturnKey(listView)

        treeView = qt.QTreeView(self)
        treeView.setSelectionBehavior(qt.QAbstractItemView.SelectRows)
        treeView.setSelectionMode(qt.QAbstractItemView.SingleSelection)
        treeView.setRootIsDecorated(False)
        treeView.setItemsExpandable(False)
        treeView.setSortingEnabled(True)
        treeView.header().setSortIndicator(0, qt.Qt.AscendingOrder)
        treeView.header().setStretchLastSection(False)
        treeView.setTextElideMode(qt.Qt.ElideMiddle)
        treeView.setEditTriggers(qt.QAbstractItemView.NoEditTriggers)
        treeView.setContextMenuPolicy(qt.Qt.CustomContextMenu)
        treeView.setDragDropMode(qt.QAbstractItemView.InternalMove)
        utils.patchToConsumeReturnKey(treeView)

        self.__browser = _Browser(self, listView, treeView)
        self.__browser.activated.connect(self.__browsedItemActivated)
        self.__browser.selected.connect(self.__browsedItemSelected)
        self.__browser.rootIndexChanged.connect(self.__rootIndexChanged)
        self.__browser.setObjectName("browser")

        self.__previewWidget = self._createPreviewWidget(self)

        self.__fileTypeCombo = FileTypeComboBox(self)
        self.__fileTypeCombo.setObjectName("fileTypeCombo")
        self.__fileTypeCombo.setDuplicatesEnabled(False)
        self.__fileTypeCombo.setSizeAdjustPolicy(qt.QComboBox.AdjustToMinimumContentsLength)
        self.__fileTypeCombo.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)
        self.__fileTypeCombo.activated[int].connect(self.__filterSelected)
        self.__fileTypeCombo.setFabioUrlSupproted(self._isFabioFilesSupported())

        self.__pathEdit = _PathEdit(self)
        self.__pathEdit.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)
        self.__pathEdit.textChanged.connect(self.__textChanged)
        self.__pathEdit.setObjectName("url")
        utils.patchToConsumeReturnKey(self.__pathEdit)

        self.__buttons = qt.QDialogButtonBox(self)
        self.__buttons.setSizePolicy(qt.QSizePolicy.Fixed, qt.QSizePolicy.Fixed)
        types = qt.QDialogButtonBox.Open | qt.QDialogButtonBox.Cancel
        self.__buttons.setStandardButtons(types)
        self.__buttons.button(qt.QDialogButtonBox.Cancel).setObjectName("cancel")
        self.__buttons.button(qt.QDialogButtonBox.Open).setObjectName("open")

        self.__buttons.accepted.connect(self.accept)
        self.__buttons.rejected.connect(self.reject)

        self.__browseToolBar = self._createBrowseToolBar()
        self.__backwardAction.setEnabled(False)
        self.__forwardAction.setEnabled(False)
        self.__fileDirectoryAction.setEnabled(False)
        self.__parentFileDirectoryAction.setEnabled(False)

        self.__selectorWidget = self._createSelectorWidget(self)
        if self.__selectorWidget is not None:
            self.__selectorWidget.selectionChanged.connect(self.__selectorWidgetChanged)

        self.__previewToolBar = self._createPreviewToolbar(self, self.__previewWidget, self.__selectorWidget)

        self.__dataIcon = qt.QLabel(self)
        self.__dataIcon.setSizePolicy(qt.QSizePolicy.Fixed, qt.QSizePolicy.Fixed)
        self.__dataIcon.setScaledContents(True)
        self.__dataIcon.setMargin(2)
        self.__dataIcon.setAlignment(qt.Qt.AlignCenter)

        self.__dataInfo = qt.QLabel(self)
        self.__dataInfo.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)

    def _createSideBar(self):
        sidebar = _SideBar(self)
        sidebar.setObjectName("sidebar")
        return sidebar

    def iconProvider(self):
        iconProvider = self.__class__._defaultIconProvider
        if iconProvider is None:
            iconProvider = _IconProvider()
            self.__class__._defaultIconProvider = iconProvider
        return iconProvider

    def _createBrowseToolBar(self):
        toolbar = qt.QToolBar(self)
        toolbar.setIconSize(qt.QSize(16, 16))
        iconProvider = self.iconProvider()

        backward = qt.QAction(toolbar)
        backward.setText("Back")
        backward.setObjectName("backwardAction")
        backward.setIcon(iconProvider.icon(qt.QStyle.SP_ArrowBack))
        backward.triggered.connect(self.__navigateBackward)
        self.__backwardAction = backward

        forward = qt.QAction(toolbar)
        forward.setText("Forward")
        forward.setObjectName("forwardAction")
        forward.setIcon(iconProvider.icon(qt.QStyle.SP_ArrowForward))
        forward.triggered.connect(self.__navigateForward)
        self.__forwardAction = forward

        parentDirectory = qt.QAction(toolbar)
        parentDirectory.setText("Go to parent")
        parentDirectory.setObjectName("toParentAction")
        parentDirectory.setIcon(iconProvider.icon(qt.QStyle.SP_FileDialogToParent))
        parentDirectory.triggered.connect(self.__navigateToParent)
        self.__toParentAction = parentDirectory

        fileDirectory = qt.QAction(toolbar)
        fileDirectory.setText("Root of the file")
        fileDirectory.setObjectName("toRootFileAction")
        fileDirectory.setIcon(iconProvider.icon(iconProvider.FileDialogToParentFile))
        fileDirectory.triggered.connect(self.__navigateToParentFile)
        self.__fileDirectoryAction = fileDirectory

        parentFileDirectory = qt.QAction(toolbar)
        parentFileDirectory.setText("Parent directory of the file")
        parentFileDirectory.setObjectName("toDirectoryAction")
        parentFileDirectory.setIcon(iconProvider.icon(iconProvider.FileDialogToParentDir))
        parentFileDirectory.triggered.connect(self.__navigateToParentDir)
        self.__parentFileDirectoryAction = parentFileDirectory

        listView = qt.QAction(toolbar)
        listView.setText("List view")
        listView.setObjectName("listModeAction")
        listView.setIcon(iconProvider.icon(qt.QStyle.SP_FileDialogListView))
        listView.triggered.connect(self.__showAsListView)
        listView.setCheckable(True)

        detailView = qt.QAction(toolbar)
        detailView.setText("Detail view")
        detailView.setObjectName("detailModeAction")
        detailView.setIcon(iconProvider.icon(qt.QStyle.SP_FileDialogDetailedView))
        detailView.triggered.connect(self.__showAsDetailedView)
        detailView.setCheckable(True)

        self.__listViewAction = listView
        self.__detailViewAction = detailView

        toolbar.addAction(backward)
        toolbar.addAction(forward)
        toolbar.addSeparator()
        toolbar.addAction(parentDirectory)
        toolbar.addAction(fileDirectory)
        toolbar.addAction(parentFileDirectory)
        toolbar.addSeparator()
        toolbar.addAction(listView)
        toolbar.addAction(detailView)

        toolbar.setStyleSheet("QToolBar { border: 0px }")

        return toolbar

    def __initLayout(self):
        sideBarLayout = qt.QVBoxLayout()
        sideBarLayout.setContentsMargins(0, 0, 0, 0)
        dummyToolBar = qt.QWidget(self)
        dummyToolBar.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)
        dummyCombo = qt.QWidget(self)
        dummyCombo.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)
        sideBarLayout.addWidget(dummyToolBar)
        if self.__sidebar is not None:
            sideBarLayout.addWidget(self.__sidebar)
        sideBarLayout.addWidget(dummyCombo)
        sideBarWidget = qt.QWidget(self)
        sideBarWidget.setLayout(sideBarLayout)

        dummyCombo.setFixedHeight(self.__fileTypeCombo.height())
        self.__resizeCombo = _CatchResizeEvent(self, self.__fileTypeCombo)
        self.__resizeCombo.resized.connect(lambda e: dummyCombo.setFixedHeight(e.size().height()))

        dummyToolBar.setFixedHeight(self.__browseToolBar.height())
        self.__resizeToolbar = _CatchResizeEvent(self, self.__browseToolBar)
        self.__resizeToolbar.resized.connect(lambda e: dummyToolBar.setFixedHeight(e.size().height()))

        datasetSelection = qt.QWidget(self)
        layoutLeft = qt.QVBoxLayout()
        layoutLeft.setContentsMargins(0, 0, 0, 0)
        layoutLeft.addWidget(self.__browseToolBar)
        layoutLeft.addWidget(self.__browser)
        layoutLeft.addWidget(self.__fileTypeCombo)
        datasetSelection.setLayout(layoutLeft)
        datasetSelection.setSizePolicy(qt.QSizePolicy.MinimumExpanding, qt.QSizePolicy.Expanding)

        infoLayout = qt.QHBoxLayout()
        infoLayout.setContentsMargins(0, 0, 0, 0)
        infoLayout.addWidget(self.__dataIcon)
        infoLayout.addWidget(self.__dataInfo)

        dataFrame = qt.QFrame(self)
        dataFrame.setFrameShape(qt.QFrame.StyledPanel)
        layout = qt.QVBoxLayout()
        layout.setContentsMargins(0, 0, 0, 0)
        layout.setSpacing(0)
        layout.addWidget(self.__previewWidget)
        layout.addLayout(infoLayout)
        dataFrame.setLayout(layout)

        dataSelection = qt.QWidget(self)
        dataLayout = qt.QVBoxLayout()
        dataLayout.setContentsMargins(0, 0, 0, 0)
        if self.__previewToolBar is not None:
            dataLayout.addWidget(self.__previewToolBar)
        else:
            # Add dummy space
            dummyToolbar2 = qt.QWidget(self)
            dummyToolbar2.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)
            dummyToolbar2.setFixedHeight(self.__browseToolBar.height())
            self.__resizeToolbar = _CatchResizeEvent(self, self.__browseToolBar)
            self.__resizeToolbar.resized.connect(lambda e: dummyToolbar2.setFixedHeight(e.size().height()))
            dataLayout.addWidget(dummyToolbar2)

        dataLayout.addWidget(dataFrame)
        if self.__selectorWidget is not None:
            dataLayout.addWidget(self.__selectorWidget)
        else:
            # Add dummy space
            dummyCombo2 = qt.QWidget(self)
            dummyCombo2.setSizePolicy(qt.QSizePolicy.Expanding, qt.QSizePolicy.Fixed)
            dummyCombo2.setFixedHeight(self.__fileTypeCombo.height())
            self.__resizeToolbar = _CatchResizeEvent(self, self.__fileTypeCombo)
            self.__resizeToolbar.resized.connect(lambda e: dummyCombo2.setFixedHeight(e.size().height()))
            dataLayout.addWidget(dummyCombo2)
        dataSelection.setLayout(dataLayout)

        self.__splitter = qt.QSplitter(self)
        self.__splitter.setContentsMargins(0, 0, 0, 0)
        self.__splitter.addWidget(sideBarWidget)
        self.__splitter.addWidget(datasetSelection)
        self.__splitter.addWidget(dataSelection)
        self.__splitter.setStretchFactor(1, 10)

        bottomLayout = qt.QHBoxLayout()
        bottomLayout.setContentsMargins(0, 0, 0, 0)
        bottomLayout.addWidget(self.__pathEdit)
        bottomLayout.addWidget(self.__buttons)

        layout = qt.QVBoxLayout(self)
        layout.addWidget(self.__splitter)
        layout.addLayout(bottomLayout)

        self.setLayout(layout)
        self.updateGeometry()

    # Logic

    def __navigateBackward(self):
        """Navigate through  the history one step backward."""
        if len(self.__currentHistory) > 0 and self.__currentHistoryLocation > 0:
            self.__currentHistoryLocation -= 1
            url = self.__currentHistory[self.__currentHistoryLocation]
            self.selectUrl(url)

    def __navigateForward(self):
        """Navigate through  the history one step forward."""
        if len(self.__currentHistory) > 0 and self.__currentHistoryLocation < len(self.__currentHistory) - 1:
            self.__currentHistoryLocation += 1
            url = self.__currentHistory[self.__currentHistoryLocation]
            self.selectUrl(url)

    def __navigateToParent(self):
        index = self.__browser.rootIndex()
        if index.model() is self.__fileModel:
            # browse throw the file system
            index = index.parent()
            path = self.__fileModel.filePath(index)
            self.__fileModel_setRootPath(path)
            self.__browser.selectIndex(qt.QModelIndex())
            self.__updatePath()
        elif index.model() is self.__dataModel:
            index = index.parent()
            if index.isValid():
                # browse throw the hdf5
                self.__browser.setRootIndex(index)
                self.__browser.selectIndex(qt.QModelIndex())
                self.__updatePath()
            else:
                # go back to the file system
                self.__navigateToParentDir()
        else:
            # Root of the file system (my computer)
            pass

    def __navigateToParentFile(self):
        index = self.__browser.rootIndex()
        if index.model() is self.__dataModel:
            index = self.__dataModel.indexFromH5Object(self.__h5)
            self.__browser.setRootIndex(index)
            self.__browser.selectIndex(qt.QModelIndex())
            self.__updatePath()

    def __navigateToParentDir(self):
        index = self.__browser.rootIndex()
        if index.model() is self.__dataModel:
            path = os.path.dirname(self.__h5.file.filename)
            index = self.__fileModel.index(path)
            self.__browser.setRootIndex(index)
            self.__browser.selectIndex(qt.QModelIndex())
            self.__closeFile()
            self.__updatePath()

    def viewMode(self):
        """Returns the current view mode.

        :rtype: qt.QFileDialog.ViewMode
        """
        return self.__browser.viewMode()

    def setViewMode(self, mode):
        """Set the current view mode.

        :param qt.QFileDialog.ViewMode mode: The new view mode
        """
        if mode == qt.QFileDialog.Detail:
            self.__browser.showDetails()
            self.__listViewAction.setChecked(False)
            self.__detailViewAction.setChecked(True)
        elif mode == qt.QFileDialog.List:
            self.__browser.showList()
            self.__listViewAction.setChecked(True)
            self.__detailViewAction.setChecked(False)
        else:
            assert(False)

    def __showAsListView(self):
        self.setViewMode(qt.QFileDialog.List)

    def __showAsDetailedView(self):
        self.setViewMode(qt.QFileDialog.Detail)

    def __shortcutSelected(self):
        self.__browser.selectIndex(qt.QModelIndex())
        self.__clearData()
        self.__updatePath()
        selectionModel = self.__sidebar.selectionModel()
        indexes = selectionModel.selectedIndexes()
        if len(indexes) == 1:
            index = indexes[0]
            url = self.__sidebar.model().data(index, role=qt.Qt.UserRole)
            path = url.toLocalFile()
            self.__fileModel_setRootPath(path)

    def __browsedItemActivated(self, index):
        if not index.isValid():
            return
        if index.model() is self.__fileModel:
            path = self.__fileModel.filePath(index)
            if self.__fileModel.isDir(index):
                self.__fileModel_setRootPath(path)
            if os.path.isfile(path):
                self.__fileActivated(index)
        elif index.model() is self.__dataModel:
            obj = self.__dataModel.data(index, role=Hdf5TreeModel.H5PY_OBJECT_ROLE)
            if silx.io.is_group(obj):
                self.__browser.setRootIndex(index)
        else:
            assert(False)

    def __browsedItemSelected(self, index):
        self.__dataSelected(index)
        self.__updatePath()

    def __fileModel_setRootPath(self, path):
        """Set the root path of the fileModel with a filter on the
        directoryLoaded event.

        Without this filter an extra event is received (at least with PyQt4)
        when we use for the first time the sidebar.

        :param str path: Path to load
        """
        assert(path is not None)
        if path != "" and not os.path.exists(path):
            return
        if self.hasPendingEvents():
            # Make sure the asynchronous fileModel setRootPath is finished
            qt.QApplication.instance().processEvents()

        if self.__directoryLoadedFilter is not None:
            if utils.samefile(self.__directoryLoadedFilter, path):
                return
        self.__directoryLoadedFilter = path
        self.__processing += 1
        index = self.__fileModel.setRootPath(path)
        if not index.isValid():
            self.__processing -= 1
            self.__browser.setRootIndex(index, model=self.__fileModel)
            self.__clearData()
            self.__updatePath()
        else:
            # asynchronous process
            pass

    def __directoryLoaded(self, path):
        if self.__directoryLoadedFilter is not None:
            if not utils.samefile(self.__directoryLoadedFilter, path):
                # Filter event which should not arrive in PyQt4
                # The first click on the sidebar sent 2 events
                self.__processing -= 1
                return
        index = self.__fileModel.index(path)
        self.__browser.setRootIndex(index, model=self.__fileModel)
        self.__updatePath()
        self.__processing -= 1

    def __closeFile(self):
        self.__openedFiles[:] = []
        self.__fileDirectoryAction.setEnabled(False)
        self.__parentFileDirectoryAction.setEnabled(False)
        if self.__h5 is not None:
            self.__dataModel.removeH5pyObject(self.__h5)
            self.__h5.close()
            self.__h5 = None
        if self.__fabio is not None:
            if hasattr(self.__fabio, "close"):
                self.__fabio.close()
            self.__fabio = None

    def __openFabioFile(self, filename):
        self.__closeFile()
        try:
            if fabio is None:
                raise ImportError("Fabio module is not available")
            self.__fabio = fabio.open(filename)
            self.__openedFiles.append(self.__fabio)
            self.__selectedFile = filename
        except Exception as e:
            _logger.error("Error while loading file %s: %s", filename, e.args[0])
            _logger.debug("Backtrace", exc_info=True)
            self.__errorWhileLoadingFile = filename, e.args[0]
            return False
        else:
            return True

    def __openSilxFile(self, filename):
        self.__closeFile()
        try:
            self.__h5 = silx.io.open(filename)
            self.__openedFiles.append(self.__h5)
            self.__selectedFile = filename
        except IOError as e:
            _logger.error("Error while loading file %s: %s", filename, e.args[0])
            _logger.debug("Backtrace", exc_info=True)
            self.__errorWhileLoadingFile = filename, e.args[0]
            return False
        else:
            self.__fileDirectoryAction.setEnabled(True)
            self.__parentFileDirectoryAction.setEnabled(True)
            self.__dataModel.insertH5pyObject(self.__h5)
            return True

    def __isSilxHavePriority(self, filename):
        """Silx have priority when there is a specific decoder
        """
        _, ext = os.path.splitext(filename)
        ext = "*%s" % ext
        formats = silx.io.supported_extensions(flat_formats=False)
        for extensions in formats.values():
            if ext in extensions:
                return True
        return False

    def __openFile(self, filename):
        codec = self.__fileTypeCombo.currentCodec()
        openners = []
        if codec.is_autodetect():
            if self.__isSilxHavePriority(filename):
                openners.append(self.__openSilxFile)
                if fabio is not None and self._isFabioFilesSupported():
                    openners.append(self.__openFabioFile)
            else:
                if fabio is not None and self._isFabioFilesSupported():
                    openners.append(self.__openFabioFile)
                openners.append(self.__openSilxFile)
        elif codec.is_silx_codec():
            openners.append(self.__openSilxFile)
        elif self._isFabioFilesSupported() and codec.is_fabio_codec():
            # It is requested to use fabio, anyway fabio is here or not
            openners.append(self.__openFabioFile)

        for openner in openners:
            ref = openner(filename)
            if ref is not None:
                return True
        return False

    def __fileActivated(self, index):
        self.__selectedFile = None
        path = self.__fileModel.filePath(index)
        if os.path.isfile(path):
            loaded = self.__openFile(path)
            if loaded:
                if self.__h5 is not None:
                    index = self.__dataModel.indexFromH5Object(self.__h5)
                    self.__browser.setRootIndex(index)
                elif self.__fabio is not None:
                    data = _FabioData(self.__fabio)
                    self.__setData(data)
                self.__updatePath()
            else:
                self.__clearData()

    def __dataSelected(self, index):
        selectedData = None
        if index is not None:
            if index.model() is self.__dataModel:
                obj = self.__dataModel.data(index, self.__dataModel.H5PY_OBJECT_ROLE)
                if self._isDataSupportable(obj):
                    selectedData = obj
            elif index.model() is self.__fileModel:
                self.__closeFile()
                if self._isFabioFilesSupported():
                    path = self.__fileModel.filePath(index)
                    if os.path.isfile(path):
                        codec = self.__fileTypeCombo.currentCodec()
                        is_fabio_decoder = codec.is_fabio_codec()
                        is_fabio_have_priority = not codec.is_silx_codec() and not self.__isSilxHavePriority(path)
                        if is_fabio_decoder or is_fabio_have_priority:
                            # Then it's flat frame container
                            if fabio is not None:
                                self.__openFabioFile(path)
                                if self.__fabio is not None:
                                    selectedData = _FabioData(self.__fabio)
            else:
                assert(False)

        self.__setData(selectedData)

    def __filterSelected(self, index):
        filters = self.__fileTypeCombo.itemExtensions(index)
        self.__fileModel.setNameFilters(list(filters))

    def __setData(self, data):
        self.__data = data

        if data is not None and self._isDataSupportable(data):
            if self.__selectorWidget is not None:
                self.__selectorWidget.setData(data)
                if not self.__selectorWidget.isUsed():
                    # Needed to fake the fact we have to reset the zoom in preview
                    self.__selectedData = None
                    self.__setSelectedData(data)
                    self.__selectorWidget.hide()
                else:
                    self.__selectorWidget.setVisible(self.__selectorWidget.hasVisibleSelectors())
                    # Needed to fake the fact we have to reset the zoom in preview
                    self.__selectedData = None
                    self.__selectorWidget.selectionChanged.emit()
            else:
                # Needed to fake the fact we have to reset the zoom in preview
                self.__selectedData = None
                self.__setSelectedData(data)
        else:
            self.__clearData()
            self.__updatePath()

    def _isDataSupported(self, data):
        """Check if the data can be returned by the dialog.

        If true, this data can be returned by the dialog and the open button
        while be enabled. If false the button will be disabled.

        :rtype: bool
        """
        raise NotImplementedError()

    def _isDataSupportable(self, data):
        """Check if the selected data can be supported at one point.

        If true, the data selector will be checked and it will update the data
        preview. Else the selecting is disabled.

        :rtype: bool
        """
        raise NotImplementedError()

    def __clearData(self):
        """Clear the data part of the GUI"""
        if self.__previewWidget is not None:
            self.__previewWidget.setData(None)
        if self.__selectorWidget is not None:
            self.__selectorWidget.hide()
        self.__selectedData = None
        self.__data = None
        self.__updateDataInfo()
        button = self.__buttons.button(qt.QDialogButtonBox.Open)
        button.setEnabled(False)

    def __selectorWidgetChanged(self):
        data = self.__selectorWidget.getSelectedData(self.__data)
        self.__setSelectedData(data)

    def __setSelectedData(self, data):
        """Set the data selected by the dialog.

        If :meth:`_isDataSupported` returns false, this function will be
        inhibited and no data will be selected.
        """
        if self.__previewWidget is not None:
            fromDataSelector = self.__selectedData is not None
            self.__previewWidget.setData(data, fromDataSelector=fromDataSelector)
        if self._isDataSupported(data):
            self.__selectedData = data
        else:
            self.__clearData()
            return
        self.__updateDataInfo()
        self.__updatePath()
        button = self.__buttons.button(qt.QDialogButtonBox.Open)
        button.setEnabled(True)

    def __updateDataInfo(self):
        if self.__errorWhileLoadingFile is not None:
            filename, message = self.__errorWhileLoadingFile
            message = "<b>Error while loading file '%s'</b><hr/>%s" % (filename, message)
            size = self.__dataInfo.height()
            icon = self.style().standardIcon(qt.QStyle.SP_MessageBoxCritical)
            pixmap = icon.pixmap(size, size)

            self.__dataInfo.setText("Error while loading file")
            self.__dataInfo.setToolTip(message)
            self.__dataIcon.setToolTip(message)
            self.__dataIcon.setVisible(True)
            self.__dataIcon.setPixmap(pixmap)

            self.__errorWhileLoadingFile = None
            return

        self.__dataIcon.setVisible(False)
        self.__dataInfo.setToolTip("")
        if self.__selectedData is None:
            self.__dataInfo.setText("No data selected")
        else:
            text = self._displayedDataInfo(self.__data, self.__selectedData)
            self.__dataInfo.setVisible(text is not None)
            if text is not None:
                self.__dataInfo.setText(text)

    def _displayedDataInfo(self, dataBeforeSelection, dataAfterSelection):
        """Returns the text displayed under the data preview.

        This zone is used to display error in case or problem of data selection
        or problems with IO.

        :param numpy.ndarray dataAfterSelection: Data as it is after the
            selection widget (basically the data from the preview widget)
        :param numpy.ndarray dataAfterSelection: Data as it is before the
            selection widget (basically the data from the browsing widget)
        :rtype: bool
        """
        return None

    def __createUrlFromIndex(self, index, useSelectorWidget=True):
        if index.model() is self.__fileModel:
            filename = self.__fileModel.filePath(index)
            dataPath = None
        elif index.model() is self.__dataModel:
            obj = self.__dataModel.data(index, role=Hdf5TreeModel.H5PY_OBJECT_ROLE)
            filename = obj.file.filename
            dataPath = obj.name
        else:
            # root of the computer
            filename = ""
            dataPath = None

        if useSelectorWidget and self.__selectorWidget is not None and self.__selectorWidget.isVisible():
            slicing = self.__selectorWidget.slicing()
        else:
            slicing = None

        if self.__fabio is not None:
            scheme = "fabio"
        elif self.__h5 is not None:
            scheme = "silx"
        else:
            if os.path.isfile(filename):
                codec = self.__fileTypeCombo.currentCodec()
                if codec.is_fabio_codec():
                    scheme = "fabio"
                elif codec.is_silx_codec():
                    scheme = "silx"
                else:
                    scheme = None
            else:
                scheme = None

        url = silx.io.url.DataUrl(file_path=filename, data_path=dataPath, data_slice=slicing, scheme=scheme)
        return url

    def __updatePath(self):
        index = self.__browser.selectedIndex()
        if index is None:
            index = self.__browser.rootIndex()
        url = self.__createUrlFromIndex(index)
        if url.path() != self.__pathEdit.text():
            old = self.__pathEdit.blockSignals(True)
            self.__pathEdit.setText(url.path())
            self.__pathEdit.blockSignals(old)

    def __rootIndexChanged(self, index):
        url = self.__createUrlFromIndex(index, useSelectorWidget=False)

        currentUrl = None
        if 0 <= self.__currentHistoryLocation < len(self.__currentHistory):
            currentUrl = self.__currentHistory[self.__currentHistoryLocation]

        if currentUrl is None or currentUrl != url.path():
            # clean up the forward history
            self.__currentHistory = self.__currentHistory[0:self.__currentHistoryLocation + 1]
            self.__currentHistory.append(url.path())
            self.__currentHistoryLocation += 1

        if index.model() != self.__dataModel:
            if sys.platform == "win32":
                # path == ""
                isRoot = not index.isValid()
            else:
                # path in ["", "/"]
                isRoot = not index.isValid() or not index.parent().isValid()
        else:
            isRoot = False

        if index.isValid():
            self.__dataSelected(index)
        self.__toParentAction.setEnabled(not isRoot)
        self.__updateActionHistory()
        self.__updateSidebar()

    def __updateSidebar(self):
        """Called when the current directory location change"""
        if self.__sidebar is None:
            return
        selectionModel = self.__sidebar.selectionModel()
        selectionModel.selectionChanged.disconnect(self.__shortcutSelected)
        index = self.__browser.rootIndex()
        if index.model() == self.__fileModel:
            path = self.__fileModel.filePath(index)
            self.__sidebar.setSelectedPath(path)
        elif index.model() is None:
            path = ""
            self.__sidebar.setSelectedPath(path)
        else:
            selectionModel.clear()
        selectionModel.selectionChanged.connect(self.__shortcutSelected)

    def __updateActionHistory(self):
        self.__forwardAction.setEnabled(len(self.__currentHistory) - 1 > self.__currentHistoryLocation)
        self.__backwardAction.setEnabled(self.__currentHistoryLocation > 0)

    def __textChanged(self, text):
        self.__pathChanged()

    def _isFabioFilesSupported(self):
        """Returns true fabio files can be loaded.
        """
        return True

    def _isLoadableUrl(self, url):
        """Returns true if the URL is loadable by this dialog.

        :param DataUrl url: The requested URL
        """
        return True

    def __pathChanged(self):
        url = silx.io.url.DataUrl(path=self.__pathEdit.text())
        if url.is_valid() or url.path() == "":
            if url.path() in ["", "/"] or url.file_path() in ["", "/"]:
                self.__fileModel_setRootPath(qt.QDir.rootPath())
            elif os.path.exists(url.file_path()):
                rootIndex = None
                if os.path.isdir(url.file_path()):
                    self.__fileModel_setRootPath(url.file_path())
                    index = self.__fileModel.index(url.file_path())
                elif os.path.isfile(url.file_path()):
                    if self._isLoadableUrl(url):
                        if url.scheme() == "silx":
                            loaded = self.__openSilxFile(url.file_path())
                        elif url.scheme() == "fabio" and self._isFabioFilesSupported():
                            loaded = self.__openFabioFile(url.file_path())
                        else:
                            loaded = self.__openFile(url.file_path())
                    else:
                        loaded = False
                    if loaded:
                        if self.__h5 is not None:
                            rootIndex = self.__dataModel.indexFromH5Object(self.__h5)
                        elif self.__fabio is not None:
                            index = self.__fileModel.index(url.file_path())
                            rootIndex = index
                    if rootIndex is None:
                        index = self.__fileModel.index(url.file_path())
                        index = index.parent()

                if rootIndex is not None:
                    if rootIndex.model() == self.__dataModel:
                        if url.data_path() is not None:
                            dataPath = url.data_path()
                            if dataPath in self.__h5:
                                obj = self.__h5[dataPath]
                            else:
                                path = utils.findClosestSubPath(self.__h5, dataPath)
                                if path is None:
                                    path = "/"
                                obj = self.__h5[path]

                            if silx.io.is_file(obj):
                                self.__browser.setRootIndex(rootIndex)
                            elif silx.io.is_group(obj):
                                index = self.__dataModel.indexFromH5Object(obj)
                                self.__browser.setRootIndex(index)
                            else:
                                index = self.__dataModel.indexFromH5Object(obj)
                                self.__browser.setRootIndex(index.parent())
                                self.__browser.selectIndex(index)
                        else:
                            self.__browser.setRootIndex(rootIndex)
                            self.__clearData()
                    elif rootIndex.model() == self.__fileModel:
                        # that's a fabio file
                        self.__browser.setRootIndex(rootIndex.parent())
                        self.__browser.selectIndex(rootIndex)
                        # data = _FabioData(self.__fabio)
                        # self.__setData(data)
                    else:
                        assert(False)
                else:
                    self.__browser.setRootIndex(index, model=self.__fileModel)
                    self.__clearData()

                if self.__selectorWidget is not None:
                    self.__selectorWidget.setVisible(url.data_slice() is not None)
                    if url.data_slice() is not None:
                        self.__selectorWidget.setSlicing(url.data_slice())
            else:
                self.__errorWhileLoadingFile = (url.file_path(), "File not found")
                self.__clearData()
        else:
            self.__errorWhileLoadingFile = (url.file_path(), "Path invalid")
            self.__clearData()

    def previewToolbar(self):
        return self.__previewToolbar

    def previewWidget(self):
        return self.__previewWidget

    def selectorWidget(self):
        return self.__selectorWidget

    def _createPreviewToolbar(self, parent, dataPreviewWidget, dataSelectorWidget):
        return None

    def _createPreviewWidget(self, parent):
        return None

    def _createSelectorWidget(self, parent):
        return None

    # Selected file

    def setDirectory(self, path):
        """Sets the data dialog's current directory."""
        self.__fileModel_setRootPath(path)

    def selectedFile(self):
        """Returns the file path containing the selected data.

        :rtype: str
        """
        return self.__selectedFile

    def selectFile(self, filename):
        """Sets the data dialog's current file."""
        self.__directoryLoadedFilter = ""
        old = self.__pathEdit.blockSignals(True)
        try:
            self.__pathEdit.setText(filename)
        finally:
            self.__pathEdit.blockSignals(old)
        self.__pathChanged()

    # Selected data

    def selectUrl(self, url):
        """Sets the data dialog's current data url.

        :param Union[str,DataUrl] url: URL identifying a data (it can be a
            `DataUrl` object)
        """
        if isinstance(url, silx.io.url.DataUrl):
            url = url.path()
        self.__directoryLoadedFilter = ""
        old = self.__pathEdit.blockSignals(True)
        try:
            self.__pathEdit.setText(url)
        finally:
            self.__pathEdit.blockSignals(old)
        self.__pathChanged()

    def selectedUrl(self):
        """Returns the URL from the file system to the data.

        If the dialog is not validated, the path can be an intermediat
        selected path, or an invalid path.

        :rtype: str
        """
        return self.__pathEdit.text()

    def selectedDataUrl(self):
        """Returns the URL as a :class:`DataUrl` from the file system to the
        data.

        If the dialog is not validated, the path can be an intermediat
        selected path, or an invalid path.

        :rtype: DataUrl
        """
        url = self.selectedUrl()
        return silx.io.url.DataUrl(url)

    def directory(self):
        """Returns the path from the current browsed directory.

        :rtype: str
        """
        if self.__directory is not None:
            # At post execution, returns the cache
            return self.__directory

        index = self.__browser.rootIndex()
        if index.model() is self.__fileModel:
            path = self.__fileModel.filePath(index)
            return path
        elif index.model() is self.__dataModel:
            path = os.path.dirname(self.__h5.file.filename)
            return path
        else:
            return ""

    def _selectedData(self):
        """Returns the internal selected data

        :rtype: numpy.ndarray
        """
        return self.__selectedData

    # Filters

    def selectedNameFilter(self):
        """Returns the filter that the user selected in the file dialog."""
        return self.__fileTypeCombo.currentText()

    # History

    def history(self):
        """Returns the browsing history of the filedialog as a list of paths.

        :rtype: List<str>
        """
        if len(self.__currentHistory) <= 1:
            return []
        history = self.__currentHistory[0:self.__currentHistoryLocation]
        return list(history)

    def setHistory(self, history):
        self.__currentHistory = []
        self.__currentHistory.extend(history)
        self.__currentHistoryLocation = len(self.__currentHistory) - 1
        self.__updateActionHistory()

    # Colormap

    def colormap(self):
        if self.__previewWidget is None:
            return None
        return self.__previewWidget.colormap()

    def setColormap(self, colormap):
        if self.__previewWidget is None:
            raise RuntimeError("No preview widget defined")
        self.__previewWidget.setColormap(colormap)

    # Sidebar

    def setSidebarUrls(self, urls):
        """Sets the urls that are located in the sidebar."""
        if self.__sidebar is None:
            return
        self.__sidebar.setUrls(urls)

    def sidebarUrls(self):
        """Returns a list of urls that are currently in the sidebar."""
        if self.__sidebar is None:
            return []
        return self.__sidebar.urls()

    # State

    __serialVersion = 1
    """Store the current version of the serialized data"""

    @classmethod
    def qualifiedName(cls):
        return "%s.%s" % (cls.__module__, cls.__name__)

    def restoreState(self, state):
        """Restores the dialogs's layout, history and current directory to the
        state specified.

        :param qt.QByteArray state: Stream containing the new state
        :rtype: bool
        """
        stream = qt.QDataStream(state, qt.QIODevice.ReadOnly)

        qualifiedName = stream.readQString()
        if qualifiedName != self.qualifiedName():
            _logger.warning("Stored state contains an invalid qualified name. %s restoration cancelled.", self.__class__.__name__)
            return False

        version = stream.readInt32()
        if version != self.__serialVersion:
            _logger.warning("Stored state contains an invalid version. %s restoration cancelled.", self.__class__.__name__)
            return False

        result = True

        splitterData = stream.readQVariant()
        sidebarUrls = stream.readQStringList()
        history = stream.readQStringList()
        workingDirectory = stream.readQString()
        browserData = stream.readQVariant()
        viewMode = stream.readInt32()
        colormapData = stream.readQVariant()

        result &= self.__splitter.restoreState(splitterData)
        sidebarUrls = [qt.QUrl(s) for s in sidebarUrls]
        self.setSidebarUrls(list(sidebarUrls))
        history = [s for s in history]
        self.setHistory(list(history))
        if workingDirectory is not None:
            self.setDirectory(workingDirectory)
        result &= self.__browser.restoreState(browserData)
        self.setViewMode(viewMode)
        colormap = self.colormap()
        if colormap is not None:
            result &= self.colormap().restoreState(colormapData)

        return result

    def saveState(self):
        """Saves the state of the dialog's layout, history and current
        directory.

        :rtype: qt.QByteArray
        """
        data = qt.QByteArray()
        stream = qt.QDataStream(data, qt.QIODevice.WriteOnly)

        s = self.qualifiedName()
        stream.writeQString(u"%s" % s)
        stream.writeInt32(self.__serialVersion)
        stream.writeQVariant(self.__splitter.saveState())
        strings = [u"%s" % s.toString() for s in self.sidebarUrls()]
        stream.writeQStringList(strings)
        strings = [u"%s" % s for s in self.history()]
        stream.writeQStringList(strings)
        stream.writeQString(u"%s" % self.directory())
        stream.writeQVariant(self.__browser.saveState())
        stream.writeInt32(self.viewMode())
        colormap = self.colormap()
        if colormap is not None:
            stream.writeQVariant(self.colormap().saveState())
        else:
            stream.writeQVariant(None)

        return data
