qutebrowser/qutebrowser/widgets/browsertab.py

# Copyright 2014 Florian Bruhin (The Compiler) <mail@qutebrowser.org>
#
# This file is part of qutebrowser.
#
# qutebrowser is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# qutebrowser is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with qutebrowser.  If not, see <http://www.gnu.org/licenses/>.

"""The main browser widgets."""

import logging
import functools

from PyQt5.QtCore import pyqtSignal, pyqtSlot, Qt
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWebKit import QWebSettings
from PyQt5.QtWebKitWidgets import QWebView, QWebPage

import qutebrowser.utils.url as urlutils
import qutebrowser.config.config as config
import qutebrowser.utils.message as message
import qutebrowser.utils.modemanager as modemanager
import qutebrowser.utils.webelem as webelem
from qutebrowser.browser.webpage import BrowserPage
from qutebrowser.browser.hints import HintManager
from qutebrowser.utils.signals import SignalCache
from qutebrowser.utils.usertypes import NeighborList


class BrowserTab(QWebView):

    """One browser tab in TabbedBrowser.

    Our own subclass of a QWebView with some added bells and whistles.

    Attributes:
        page_: The QWebPage behind the view
        signal_cache: The signal cache associated with the view.
        hintmanager: The HintManager instance for this view.
        _zoom: A NeighborList with the zoom levels.
        _scroll_pos: The old scroll position.
        _shutdown_callback: Callback to be called after shutdown.
        _open_target: Where to open the next tab ("normal", "tab", "bgtab")
        _force_open_target: Override for _open_target.
        _shutdown_callback: The callback to call after shutting down.
        _destroyed: Dict of all items to be destroyed on shtudown.

    Signals:
        scroll_pos_changed: Scroll percentage of current tab changed.
                            arg 1: x-position in %.
                            arg 2: y-position in %.
        open_tab: A new tab should be opened.
                  arg 1: The address to open
                  arg 2: Whether to open the tab in the background
        linkHovered: QWebPages linkHovered signal exposed.
    """

    scroll_pos_changed = pyqtSignal(int, int)
    open_tab = pyqtSignal('QUrl', bool)
    linkHovered = pyqtSignal(str, str, str)

    def __init__(self, parent=None):
        super().__init__(parent)
        self._scroll_pos = (-1, -1)
        self._shutdown_callback = None
        self._open_target = "normal"
        self._force_open_target = None
        self._destroyed = {}
        self._zoom = None
        self._init_neighborlist()
        self.page_ = BrowserPage(self)
        self.setPage(self.page_)
        self.hintmanager = HintManager(self)
        self.hintmanager.mouse_event.connect(self.on_mouse_event)
        self.hintmanager.set_open_target.connect(self.set_force_open_target)
        self.signal_cache = SignalCache(uncached=['linkHovered'])
        self.page_.setLinkDelegationPolicy(QWebPage.DelegateAllLinks)
        self.page_.linkHovered.connect(self.linkHovered)
        self.linkClicked.connect(self.on_link_clicked)
        self.loadFinished.connect(self.on_load_finished)
        # FIXME find some way to hide scrollbars without setScrollBarPolicy

    def _init_neighborlist(self):
        """Initialize the _zoom neighborlist."""
        self._zoom = NeighborList(
            config.get('general', 'zoomlevels'),
            default=config.get('general', 'defaultzoom'),
            mode=NeighborList.BLOCK)

    def _on_destroyed(self, sender):
        """Called when a subsystem has been destroyed during shutdown.

        Args:
            sender: The object which called the callback.
        """
        self._destroyed[sender] = True
        dbgout = '\n'.join(['{}: {}'.format(k.__class__.__name__, v)
                           for (k, v) in self._destroyed.items()])
        logging.debug("{} has been destroyed, new status:\n{}".format(
            sender.__class__.__name__, dbgout))
        if all(self._destroyed.values()):
            if self._shutdown_callback is not None:
                logging.debug("Everything destroyed, calling callback")
                self._shutdown_callback()

    def _is_editable(self, hitresult):
        """Check if a hit result needs keyboard focus.

        Args:
            hitresult: A QWebHitTestResult
        """
        # FIXME is this algorithm accurate?
        if hitresult.isContentEditable():
            # text fields and the like
            return True
        if not config.get('general', 'insert_mode_on_plugins'):
            return False
        elem = hitresult.element()
        tag = elem.tagName().lower()
        if tag in ['embed', 'applet']:
            # Flash/Java/...
            return True
        if tag == 'object':
            # Could be Flash/Java/..., could be image/audio/...
            if not elem.hasAttribute("type"):
                logging.debug("<object> without type clicked...")
                return False
            objtype = elem.attribute("type")
            if (objtype.startswith("application/") or
                    elem.hasAttribute("classid")):
                # Let's hope flash/java stuff has an application/* mimetype OR
                # at least a classid attribute. Oh, and let's home images/...
                # DON"T have a classid attribute. HTML sucks.
                logging.debug("<object type=\"{}\"> clicked.".format(objtype))
                return True
        return False

    def openurl(self, url):
        """Open an URL in the browser.

        Args:
            url: The URL to load, as string or QUrl.

        Return:
            Return status of self.load

        Emit:
            titleChanged and urlChanged
        """
        try:
            u = urlutils.fuzzy_url(url)
        except urlutils.SearchEngineError as e:
            message.error(str(e))
            return
        logging.debug('New title: {}'.format(urlutils.urlstring(u)))
        self.titleChanged.emit(urlutils.urlstring(u))
        self.urlChanged.emit(urlutils.qurl(u))
        return self.load(u)

    def zoom(self, offset):
        """Increase/Decrease the zoom level.

        Args:
            offset: The offset in the zoom level list.
        """
        level = self._zoom.getitem(offset)
        self.setZoomFactor(float(level) / 100)
        message.info("Zoom level: {}%".format(level))

    def shutdown(self, callback=None):
        """Shut down the tab cleanly and remove it.

        Inspired by [1].

        [1] https://github.com/integricho/path-of-a-pyqter/tree/master/qttut08

        Args:
            callback: Function to call after shutting down.
        """
        self._shutdown_callback = callback
        try:
            # Avoid loading finished signal when stopping
            self.loadFinished.disconnect()
        except TypeError:
            logging.exception("This should never happen.")
        self.stop()
        self.close()
        self.settings().setAttribute(QWebSettings.JavascriptEnabled, False)

        self._destroyed[self.page_] = False
        self.page_.destroyed.connect(functools.partial(self._on_destroyed,
                                                       self.page_))
        self.page_.deleteLater()

        self._destroyed[self] = False
        self.destroyed.connect(functools.partial(self._on_destroyed, self))
        self.deleteLater()

        netman = self.page_.network_access_manager
        self._destroyed[netman] = False
        netman.abort_requests()
        netman.destroyed.connect(functools.partial(self._on_destroyed, netman))
        netman.deleteLater()
        logging.debug("Tab shutdown scheduled")

    @pyqtSlot(str)
    def on_link_clicked(self, url):
        """Handle a link.

        Called from the linkClicked signal. Checks if it should open it in a
        tab (middle-click or control) or not, and does so.

        Args:
            url: The url to handle, as string or QUrl.

        Emit:
            open_tab: Emitted if window should be opened in a new tab.
        """
        if self._open_target == "tab":
            self.open_tab.emit(url, False)
        elif self._open_target == "bgtab":
            self.open_tab.emit(url, True)
        else:
            self.openurl(url)

    @pyqtSlot(str, str)
    def on_config_changed(self, section, option):
        """Update tab config when config was changed."""
        if section == 'general' and option in ['zoomlevels', 'defaultzoom']:
            self._init_neighborlist()

    @pyqtSlot('QMouseEvent')
    def on_mouse_event(self, evt):
        """Post a new mouseevent from a hintmanager."""
        self.setFocus()
        QApplication.postEvent(self, evt)

    @pyqtSlot(bool)
    def on_load_finished(self, ok):
        """Handle insert mode after loading finished."""
        if not ok:
            modemanager.maybe_leave("insert")
        elif config.get('general', 'auto_insert_mode'):
            frame = self.page_.currentFrame()
            elem = frame.findFirstElement(
                webelem.SELECTORS['editable_focused'])
            logging.debug("focus element: {}".format(not elem.isNull()))
            if elem.isNull():
                modemanager.maybe_leave("insert")
            else:
                modemanager.enter("insert")
        else:
            modemanager.maybe_leave("insert")

    @pyqtSlot(str)
    def set_force_open_target(self, target):
        """Change the forced link target. Setter for _force_open_target.

        Args:
            target: A string to set self._force_open_target to.
        """
        self._force_open_target = target

    def paintEvent(self, e):
        """Extend paintEvent to emit a signal if the scroll position changed.

        This is a bit of a hack: We listen to repaint requests here, in the
        hope a repaint will always be requested when scrolling, and if the
        scroll position actually changed, we emit a signal.

        Args:
            e: The QPaintEvent.

        Emit:
            scroll_pos_changed; If the scroll position changed.

        Return:
            The superclass event return value.
        """
        frame = self.page_.mainFrame()
        new_pos = (frame.scrollBarValue(Qt.Horizontal),
                   frame.scrollBarValue(Qt.Vertical))
        if self._scroll_pos != new_pos:
            self._scroll_pos = new_pos
            logging.debug("Updating scroll position")
            m = (frame.scrollBarMaximum(Qt.Horizontal),
                 frame.scrollBarMaximum(Qt.Vertical))
            perc = (round(100 * new_pos[0] / m[0]) if m[0] != 0 else 0,
                    round(100 * new_pos[1] / m[1]) if m[1] != 0 else 0)
            self.scroll_pos_changed.emit(*perc)
        # Let superclass handle the event
        return super().paintEvent(e)

    def mousePressEvent(self, e):
        """Extend QWidget::mousePressEvent().

        This does the following things:
            - Check if a link was clicked with the middle button or Ctrl and
              set the _open_target attribute accordingly.
            - Emit the editable_elem_selected signal if an editable element was
              clicked.

        Args:
            e: The arrived event.

        Return:
            The superclass return value.
        """
        pos = e.pos()
        frame = self.page_.frameAt(pos)
        pos -= frame.geometry().topLeft()
        hitresult = frame.hitTestContent(pos)
        if self._is_editable(hitresult):
            logging.debug("Clicked editable element!")
            modemanager.enter("insert")
        else:
            logging.debug("Clicked non-editable element!")
            try:
                modemanager.leave("insert")
            except ValueError:
                pass

        if self._force_open_target is not None:
            self._open_target = self._force_open_target
            self._force_open_target = None
            logging.debug("Setting force target: {}".format(
                self._open_target))
        elif (e.button() == Qt.MidButton or
              e.modifiers() & Qt.ControlModifier):
            if config.get('general', 'background_tabs'):
                self._open_target = "bgtab"
            else:
                self._open_target = "tab"
            logging.debug("Setting target: {}".format(self._open_target))
        else:
            self._open_target = "normal"
        return super().mousePressEvent(e)