src/Gui/EmbeddedWebView.cpp

   1 /* Copyright (C) 2006 - 2014 Jan Kundrát <jkt@flaska.net>
   2
   3    This file is part of the Trojita Qt IMAP e-mail client,
   4    http://trojita.flaska.net/
   5
   6    This program is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU General Public License as
   8    published by the Free Software Foundation; either version 2 of
   9    the License or (at your option) version 3 or any later version
  10    accepted by the membership of KDE e.V. (or its successor approved
  11    by the membership of KDE e.V.), which shall act as a proxy
  12    defined in Section 14 of version 3 of the license.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22 #include "EmbeddedWebView.h"
  23 #include "MessageView.h"
  24 #include "Gui/Util.h"
  25
  26 #include <QAbstractScrollArea>
  27 #include <QAction>
  28 #include <QApplication>
  29 #include <QDesktopServices>
  30 #include <QDesktopWidget>
  31 #include <QLayout>
  32 #include <QMouseEvent>
  33 #include <QNetworkReply>
  34 #include <QScrollBar>
  35 #include <QStyle>
  36 #include <QStyleFactory>
  37 #include <QTimer>
  38 #include <QWebFrame>
  39 #include <QWebHistory>
  40
  41 #include <QDebug>
  42
  43 namespace {
  44
  45 /** @short RAII pattern for counter manipulation */
  46 class Incrementor {
  47     int *m_int;
  48 public:
  49     Incrementor(int *what): m_int(what)
  50     {
  51         ++(*m_int);
  52     }
  53     ~Incrementor()
  54     {
  55         --(*m_int);
  56         Q_ASSERT(*m_int >= 0);
  57     }
  58 };
  59
  60 }
  61
  62 namespace Gui
  63 {
  64
  65 EmbeddedWebView::EmbeddedWebView(QWidget *parent, QNetworkAccessManager *networkManager):
  66     QWebView(parent), m_scrollParent(0L), m_resizeInProgress(0), m_staticWidth(0)
  67 {
  68     // set to expanding, ie. "freely" - this is important so the widget will attempt to shrink below the sizehint!
  69     setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
  70     setFocusPolicy(Qt::StrongFocus); // not by the wheel
  71     setPage(new ErrorCheckingPage(this));
  72     page()->setNetworkAccessManager(networkManager);
  73
  74     QWebSettings *s = settings();
  75     s->setAttribute(QWebSettings::JavascriptEnabled, false);
  76     s->setAttribute(QWebSettings::JavaEnabled, false);
  77     s->setAttribute(QWebSettings::PluginsEnabled, false);
  78     s->setAttribute(QWebSettings::PrivateBrowsingEnabled, true);
  79     s->setAttribute(QWebSettings::JavaEnabled, false);
  80     s->setAttribute(QWebSettings::OfflineStorageDatabaseEnabled, false);
  81     s->setAttribute(QWebSettings::OfflineWebApplicationCacheEnabled, false);
  82     s->setAttribute(QWebSettings::LocalStorageDatabaseEnabled, false);
  83     s->clearMemoryCaches();
  84
  85     page()->setLinkDelegationPolicy(QWebPage::DelegateAllLinks);
  86     connect(this, &QWebView::linkClicked, this, &EmbeddedWebView::slotLinkClicked);
  87     connect(this, &QWebView::loadFinished, this, &EmbeddedWebView::handlePageLoadFinished);
  88     connect(page()->mainFrame(), &QWebFrame::contentsSizeChanged, this, &EmbeddedWebView::handlePageLoadFinished);
  89
  90     // Scrolling is implemented on upper layers
  91     page()->mainFrame()->setScrollBarPolicy(Qt::Horizontal, Qt::ScrollBarAlwaysOff);
  92     page()->mainFrame()->setScrollBarPolicy(Qt::Vertical, Qt::ScrollBarAlwaysOff);
  93
  94     // Setup shortcuts for standard actions
  95     QAction *copyAction = page()->action(QWebPage::Copy);
  96     copyAction->setShortcut(tr("Ctrl+C"));
  97     addAction(copyAction);
  98
  99     // Redmine#3, the QWebView uses black text color when rendering stuff on dark background
 100     QPalette palette = QApplication::palette();
 101     if (palette.background().color().lightness() < 50) {
 102         QStyle *style = QStyleFactory::create(QLatin1String("windows"));
 103         Q_ASSERT(style);
 104         palette = style->standardPalette();
 105         setPalette(palette);
 106     }
 107
 108     m_autoScrollTimer = new QTimer(this);
 109     m_autoScrollTimer->setInterval(50);
 110     connect(m_autoScrollTimer, &QTimer::timeout, this, &EmbeddedWebView::autoScroll);
 111
 112     m_sizeContrainTimer = new QTimer(this);
 113     m_sizeContrainTimer->setInterval(50);
 114     m_sizeContrainTimer->setSingleShot(true);
 115     connect(m_sizeContrainTimer, &QTimer::timeout, this, &EmbeddedWebView::constrainSize);
 116
 117     setContextMenuPolicy(Qt::NoContextMenu);
 118     findScrollParent();
 119 }
 120
 121 void EmbeddedWebView::constrainSize()
 122 {
 123     Incrementor dummy(&m_resizeInProgress);
 124
 125     if (!(m_scrollParent && page() && page()->mainFrame()))
 126         return; // should not happen but who knows
 127
 128     // Prevent expensive operation where a resize triggers one extra resizing operation.
 129     // This is very visible on large attachments, and in fact could possibly lead to recursion as the
 130     // contentsSizeChanged signal is connected to handlePageLoadFinished.
 131     if (m_resizeInProgress > 1)
 132         return;
 133
 134     // the m_scrollParentPadding measures the summed up horizontal paddings of this view compared to
 135     // its m_scrollParent
 136     setMinimumSize(0,0);
 137     setMaximumSize(QWIDGETSIZE_MAX, QWIDGETSIZE_MAX);
 138     if (m_staticWidth) {
 139         resize(m_staticWidth, QWIDGETSIZE_MAX - 1);
 140         page()->setViewportSize(QSize(m_staticWidth, 32));
 141     } else {
 142         // resize so that the viewport has much vertical and wanted horizontal space
 143         resize(m_scrollParent->width() - m_scrollParentPadding, QWIDGETSIZE_MAX);
 144         // resize the PAGES viewport to this width and a minimum height
 145         page()->setViewportSize(QSize(m_scrollParent->width() - m_scrollParentPadding, 32));
 146     }
 147     // now the page has an idea about it's demanded size
 148     const QSize bestSize = page()->mainFrame()->contentsSize();
 149     // set the viewport to that size! - Otherwise it'd still be our "suggestion"
 150     page()->setViewportSize(bestSize);
 151     // fix the widgets size so the layout doesn't have much choice
 152     setFixedSize(bestSize);
 153     m_sizeContrainTimer->stop(); // we caused spurious resize events
 154 }
 155
 156 void EmbeddedWebView::slotLinkClicked(const QUrl &url)
 157 {
 158     // Only allow external http:// and https:// links for safety reasons
 159     if (url.scheme().toLower() == QLatin1String("http") || url.scheme().toLower() == QLatin1String("https")) {
 160         QDesktopServices::openUrl(url);
 161     } else if (url.scheme().toLower() == QLatin1String("mailto")) {
 162         // The mailto: scheme is registered by Gui::MainWindow and handled internally;
 163         // even if it wasn't, opening a third-party application in response to a
 164         // user-initiated click does not pose a security risk
 165         QUrl betterUrl(url);
 166         betterUrl.setScheme(url.scheme().toLower());
 167         QDesktopServices::openUrl(betterUrl);
 168     }
 169 }
 170
 171 void EmbeddedWebView::handlePageLoadFinished()
 172 {
 173     constrainSize();
 174
 175     // We've already set in in our constructor, but apparently it isn't enough (Qt 4.8.0 on X11).
 176     // Let's do it again here, it works.
 177     Qt::ScrollBarPolicy policy = isWindow() ? Qt::ScrollBarAsNeeded : Qt::ScrollBarAlwaysOff;
 178     page()->mainFrame()->setScrollBarPolicy(Qt::Horizontal, policy);
 179     page()->mainFrame()->setScrollBarPolicy(Qt::Vertical, policy);
 180     page()->setLinkDelegationPolicy(QWebPage::DelegateAllLinks);
 181 }
 182
 183 void EmbeddedWebView::changeEvent(QEvent *e)
 184 {
 185     QWebView::changeEvent(e);
 186     if (e->type() == QEvent::ParentChange)
 187         findScrollParent();
 188 }
 189
 190 bool EmbeddedWebView::eventFilter(QObject *o, QEvent *e)
 191 {
 192     if (o == m_scrollParent) {
 193         if (e->type() == QEvent::Resize) {
 194             if (!m_staticWidth)
 195                 m_sizeContrainTimer->start();
 196         } else if (e->type() == QEvent::Enter) {
 197             m_autoScrollPixels = 0;
 198             m_autoScrollTimer->stop();
 199         }
 200     }
 201     return QWebView::eventFilter(o, e);
 202 }
 203
 204 void EmbeddedWebView::autoScroll()
 205 {
 206     if (!(m_scrollParent && m_autoScrollPixels)) {
 207         m_autoScrollPixels = 0;
 208         m_autoScrollTimer->stop();
 209         return;
 210     }
 211     if (QScrollBar *bar = static_cast<QAbstractScrollArea*>(m_scrollParent)->verticalScrollBar()) {
 212         bar->setValue(bar->value() + m_autoScrollPixels);
 213     }
 214 }
 215
 216 void EmbeddedWebView::mouseMoveEvent(QMouseEvent *e)
 217 {
 218     if ((e->buttons() & Qt::LeftButton) && m_scrollParent) {
 219         m_autoScrollPixels = 0;
 220         const QPoint pos = mapTo(m_scrollParent, e->pos());
 221         if (pos.y() < 0)
 222             m_autoScrollPixels = pos.y();
 223         else if (pos.y() > m_scrollParent->rect().height())
 224             m_autoScrollPixels = pos.y() - m_scrollParent->rect().height();
 225         autoScroll();
 226         m_autoScrollTimer->start();
 227     }
 228     QWebView::mouseMoveEvent(e);
 229 }
 230
 231 void EmbeddedWebView::mouseReleaseEvent(QMouseEvent *e)
 232 {
 233     if (!(e->buttons() & Qt::LeftButton)) {
 234         m_autoScrollPixels = 0;
 235         m_autoScrollTimer->stop();
 236     }
 237     QWebView::mouseReleaseEvent(e);
 238 }
 239
 240 void EmbeddedWebView::findScrollParent()
 241 {
 242     if (m_scrollParent)
 243         m_scrollParent->removeEventFilter(this);
 244     m_scrollParent = 0;
 245     const int frameWidth = 2*style()->pixelMetric(QStyle::PM_DefaultFrameWidth);
 246     m_scrollParentPadding = frameWidth;
 247     QWidget *runner = this;
 248     int left, top, right, bottom;
 249     while (runner) {
 250         runner->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
 251         runner->getContentsMargins(&left, &top, &right, &bottom);
 252         m_scrollParentPadding += left + right + frameWidth;
 253         if (runner->layout()) {
 254             runner->layout()->getContentsMargins(&left, &top, &right, &bottom);
 255             m_scrollParentPadding += left + right;
 256         }
 257         QWidget *p = runner->parentWidget();
 258         if (p && qobject_cast<MessageView*>(runner) && // is this a MessageView?
 259             p->objectName() == QLatin1String("qt_scrollarea_viewport") && // in a viewport?
 260             qobject_cast<QAbstractScrollArea*>(p->parentWidget())) { // that is used?
 261             p->getContentsMargins(&left, &top, &right, &bottom);
 262             m_scrollParentPadding += left + right + frameWidth;
 263             if (p->layout()) {
 264                 p->layout()->getContentsMargins(&left, &top, &right, &bottom);
 265                 m_scrollParentPadding += left + right;
 266             }
 267             m_scrollParent = p->parentWidget();
 268             break; // then we have our actual message view
 269         }
 270         runner = p;
 271     }
 272     m_scrollParentPadding += style()->pixelMetric(QStyle::PM_ScrollBarExtent, 0, m_scrollParent);
 273     if (m_scrollParent)
 274         m_scrollParent->installEventFilter(this);
 275 }
 276
 277 void EmbeddedWebView::showEvent(QShowEvent *se)
 278 {
 279     QWebView::showEvent(se);
 280     Qt::ScrollBarPolicy policy = isWindow() ? Qt::ScrollBarAsNeeded : Qt::ScrollBarAlwaysOff;
 281     page()->mainFrame()->setScrollBarPolicy(Qt::Horizontal, Qt::ScrollBarAsNeeded);
 282     page()->mainFrame()->setScrollBarPolicy(Qt::Vertical, policy);
 283     if (isWindow()) {
 284         resize(640,480);
 285     } else if (!m_scrollParent) // it would be much easier if the parents were just passed with the constructor ;-)
 286         findScrollParent();
 287 }
 288
 289 QSize EmbeddedWebView::sizeHint() const
 290 {
 291     return QSize(32,32); // QWebView returns 800x600 what will lead to too wide pages for our implementation
 292 }
 293
 294 QWidget *EmbeddedWebView::scrollParent() const
 295 {
 296     return m_scrollParent;
 297 }
 298
 299 void EmbeddedWebView::setStaticWidth(int staticWidth)
 300 {
 301     m_staticWidth = staticWidth;
 302 }
 303
 304 int EmbeddedWebView::staticWidth() const
 305 {
 306     return m_staticWidth;
 307 }
 308
 309 ErrorCheckingPage::ErrorCheckingPage(QObject *parent): QWebPage(parent)
 310 {
 311 }
 312
 313 bool ErrorCheckingPage::supportsExtension(Extension extension) const
 314 {
 315     if (extension == ErrorPageExtension)
 316         return true;
 317     else
 318         return false;
 319 }
 320
 321 bool ErrorCheckingPage::extension(Extension extension, const ExtensionOption *option, ExtensionReturn *output)
 322 {
 323     if (extension != ErrorPageExtension)
 324         return false;
 325
 326     const ErrorPageExtensionOption *input = static_cast<const ErrorPageExtensionOption *>(option);
 327     ErrorPageExtensionReturn *res = static_cast<ErrorPageExtensionReturn *>(output);
 328     if (input && res) {
 329         if (input->url.scheme() == QLatin1String("trojita-imap")) {
 330             if (input->domain == QtNetwork && input->error == QNetworkReply::TimeoutError) {
 331                 res->content = tr("<img src='%2'/><span style='font-family: sans-serif; color: gray'>"
 332                                   "Uncached data not available when offline</span>")
 333                         .arg(Util::resizedImageAsDataUrl(QLatin1String(":/icons/network-offline.png"), 32)).toUtf8();
 334                 return true;
 335             }
 336         }
 337         res->content = input->errorString.toUtf8();
 338         res->contentType = QLatin1String("text/plain");
 339     }
 340     return true;
 341 }
 342
 343 }