Windows: Introduce QFileDialog::DontUseCustomDirectoryIcons

Folders can have a custom icon, set by the user. Some system
folders also have one, for example c:\windows\fonts.

This option allows you to disable this behavior, you'll get the
folder directory icon.

As a side-effect, you'll get a very big performance improvement
on removable/network media: 2 seconds vs 60 seconds on a SDCard
with 10000 folders.

Change-Id: Id55ea628186e0a6523585ec7a4ff622d6f5da505
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

13 files changed, 126 insertions, 25 deletions

diff --git a/src/gui/kernel/qplatformdialoghelper.h b/src/gui/kernel/qplatformdialoghelper.h
index ecc00ed8c6..f9a8a33354 100644
--- a/src/gui/kernel/qplatformdialoghelper.h
+++ b/src/gui/kernel/qplatformdialoghelper.h
@@ -217,13 +217,14 @@ public:
 
     enum FileDialogOption
     {
-        ShowDirsOnly          = 0x00000001,
-        DontResolveSymlinks   = 0x00000002,
-        DontConfirmOverwrite  = 0x00000004,
-        DontUseSheet          = 0x00000008,
-        DontUseNativeDialog   = 0x00000010,
-        ReadOnly              = 0x00000020,
-        HideNameFilterDetails = 0x00000040
+        ShowDirsOnly                = 0x00000001,
+        DontResolveSymlinks         = 0x00000002,
+        DontConfirmOverwrite        = 0x00000004,
+        DontUseSheet                = 0x00000008,
+        DontUseNativeDialog         = 0x00000010,
+        ReadOnly                    = 0x00000020,
+        HideNameFilterDetails       = 0x00000040,
+        DontUseCustomDirectoryIcons = 0x00000080
     };
     Q_DECLARE_FLAGS(FileDialogOptions, FileDialogOption)
 
diff --git a/src/gui/kernel/qplatformtheme.cpp b/src/gui/kernel/qplatformtheme.cpp
index 02b69bcb4d..098b8dad66 100644
--- a/src/gui/kernel/qplatformtheme.cpp
+++ b/src/gui/kernel/qplatformtheme.cpp
@@ -208,10 +208,12 @@ QPixmap QPlatformTheme::standardPixmap(StandardPixmap sp, const QSizeF &size) co
     return QPixmap();
 }
 
-QPixmap QPlatformTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size) const
+QPixmap QPlatformTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
+                                       QPlatformTheme::IconOptions iconOptions) const
 {
     Q_UNUSED(fileInfo);
     Q_UNUSED(size);
+    Q_UNUSED(iconOptions);
     // TODO Should return QCommonStyle pixmaps?
     return QPixmap();
 }
diff --git a/src/gui/kernel/qplatformtheme.h b/src/gui/kernel/qplatformtheme.h
index 80ba29a028..f974f18908 100644
--- a/src/gui/kernel/qplatformtheme.h
+++ b/src/gui/kernel/qplatformtheme.h
@@ -253,6 +253,11 @@ public:
         AnimateToolBoxUiEffect = 0x40
     };
 
+    enum IconOption {
+        DontUseCustomDirectoryIcons = 0x01
+    };
+    Q_DECLARE_FLAGS(IconOptions, IconOption)
+
     explicit QPlatformTheme();
     virtual ~QPlatformTheme();
 
@@ -274,7 +279,8 @@ public:
     virtual QVariant themeHint(ThemeHint hint) const;
 
     virtual QPixmap standardPixmap(StandardPixmap sp, const QSizeF &size) const;
-    virtual QPixmap fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size) const;
+    virtual QPixmap fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
+                                   QPlatformTheme::IconOptions iconOptions = 0) const;
 
     virtual QIconEngine *createIconEngine(const QString &iconName) const;
 
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.h b/src/plugins/platforms/cocoa/qcocoatheme.h
index cac059763d..e4237c9b3e 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.h
+++ b/src/plugins/platforms/cocoa/qcocoatheme.h
@@ -68,7 +68,9 @@ public:
     const QPalette *palette(Palette type = SystemPalette) const;
     const QFont *font(Font type = SystemFont) const;
     QPixmap standardPixmap(StandardPixmap sp, const QSizeF &size) const;
-    QPixmap fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size) const;
+    QPixmap fileIconPixmap(const QFileInfo &fileInfo,
+                           const QSizeF &size,
+                           QPlatformTheme::IconOptions options = 0) const;
 
     QVariant themeHint(ThemeHint hint) const;
 
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.mm b/src/plugins/platforms/cocoa/qcocoatheme.mm
index 36d7a49746..31bbd63e36 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.mm
+++ b/src/plugins/platforms/cocoa/qcocoatheme.mm
@@ -249,8 +249,10 @@ QPixmap QCocoaTheme::standardPixmap(StandardPixmap sp, const QSizeF &size) const
     return QPlatformTheme::standardPixmap(sp, size);
 }
 
-QPixmap QCocoaTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size) const
+QPixmap QCocoaTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
+                                    QPlatformTheme::IconOptions iconOptions) const
 {
+    Q_UNUSED(iconOptions);
     QCocoaAutoReleasePool pool;
 
     NSImage *iconImage = [[NSWorkspace sharedWorkspace] iconForFile:QCFString::toNSString(fileInfo.canonicalFilePath())];
diff --git a/src/plugins/platforms/windows/qwindowstheme.cpp b/src/plugins/platforms/windows/qwindowstheme.cpp
index 844e46eec5..2531dc681a 100644
--- a/src/plugins/platforms/windows/qwindowstheme.cpp
+++ b/src/plugins/platforms/windows/qwindowstheme.cpp
@@ -595,7 +595,8 @@ public:
     void operator delete (void *) {}
 };
 
-QPixmap QWindowsTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size) const
+QPixmap QWindowsTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
+                                      QPlatformTheme::IconOptions iconOptions) const
 {
     /* We don't use the variable, but by storing it statically, we
      * ensure CoInitialize is only called once. */
@@ -604,6 +605,8 @@ QPixmap QWindowsTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &s
 
     static QCache<QString, FakePointer<int> > dirIconEntryCache(1000);
     static QMutex mx;
+    static int defaultFolderIIcon = 0;
+    const bool useDefaultFolderIcon = iconOptions & QPlatformTheme::DontUseCustomDirectoryIcons;
 
     QPixmap pixmap;
     const QString filePath = QDir::toNativeSeparators(fileInfo.filePath());
@@ -612,7 +615,8 @@ QPixmap QWindowsTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &s
     bool cacheableDirIcon = fileInfo.isDir() && !fileInfo.isRoot();
     if (cacheableDirIcon) {
         QMutexLocker locker(&mx);
-        int iIcon = **dirIconEntryCache.object(filePath);
+        int iIcon = (useDefaultFolderIcon && defaultFolderIIcon) ? defaultFolderIIcon
+                                                                 : **dirIconEntryCache.object(filePath);
         if (iIcon) {
             QPixmapCache::find(dirIconPixmapCacheKey(iIcon, iconSize), pixmap);
             if (pixmap.isNull()) // Let's keep both caches in sync
@@ -629,13 +633,24 @@ QPixmap QWindowsTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &s
 #else
         iconSize|SHGFI_SYSICONINDEX;
 #endif // Q_OS_WINCE
-    unsigned long val = SHGetFileInfo((const wchar_t *)filePath.utf16(), 0,
-                                      &info, sizeof(SHFILEINFO), flags);
+    unsigned long val = 0;
+    if (cacheableDirIcon && useDefaultFolderIcon) {
+        flags |= SHGFI_USEFILEATTRIBUTES;
+        val = SHGetFileInfo(L"dummy",
+                            FILE_ATTRIBUTE_DIRECTORY,
+                            &info, sizeof(SHFILEINFO), flags);
+    } else {
+        val = SHGetFileInfo(reinterpret_cast<const wchar_t *>(filePath.utf16()), 0,
+                            &info, sizeof(SHFILEINFO), flags);
+    }
 
     // Even if GetFileInfo returns a valid result, hIcon can be empty in some cases
     if (val && info.hIcon) {
         QString key;
         if (cacheableDirIcon) {
+            if (useDefaultFolderIcon && !defaultFolderIIcon)
+                defaultFolderIIcon = info.iIcon;
+
             //using the unique icon index provided by windows save us from duplicate keys
             key = dirIconPixmapCacheKey(info.iIcon, iconSize);
             QPixmapCache::find(key, pixmap);
diff --git a/src/plugins/platforms/windows/qwindowstheme.h b/src/plugins/platforms/windows/qwindowstheme.h
index bbd7f4623f..9346621d59 100644
--- a/src/plugins/platforms/windows/qwindowstheme.h
+++ b/src/plugins/platforms/windows/qwindowstheme.h
@@ -68,7 +68,8 @@ public:
         { return m_fonts[type]; }
 
     virtual QPixmap standardPixmap(StandardPixmap sp, const QSizeF &size) const;
-    virtual QPixmap fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size) const;
+    virtual QPixmap fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
+                                   QPlatformTheme::IconOptions iconOptions = 0) const;
 
     void windowsThemeChanged(QWindow *window);
 
diff --git a/src/widgets/dialogs/qfiledialog.cpp b/src/widgets/dialogs/qfiledialog.cpp
index e6b6c2b73f..657c8cc7c2 100644
--- a/src/widgets/dialogs/qfiledialog.cpp
+++ b/src/widgets/dialogs/qfiledialog.cpp
@@ -255,6 +255,11 @@ Q_WIDGETS_EXPORT _qt_filedialog_save_file_url_hook qt_filedialog_save_file_url_h
     static functions will always be an application modal dialog. If
     you want to use sheets, use QFileDialog::open() instead.
 
+    \value DontUseCustomDirectoryIcons Always use the default directory icon.
+    Some platforms allow the user to set a different icon. Custom icon lookup
+    cause a big performance impact over network or removable drives.
+    Setting this will enable the QFileIconProvider::DontUseCustomDirectoryIcons
+    option in the icon provider. This enum value was added in Qt 5.2.
 */
 
 /*!
@@ -754,6 +759,15 @@ void QFileDialog::setOptions(Options options)
 
     if (changed & ShowDirsOnly)
         setFilter((options & ShowDirsOnly) ? filter() & ~QDir::Files : filter() | QDir::Files);
+
+    if (changed & DontUseCustomDirectoryIcons) {
+        QFileIconProvider::Options providerOptions = iconProvider()->options();
+        if (options & DontUseCustomDirectoryIcons)
+            providerOptions |= QFileIconProvider::DontUseCustomDirectoryIcons;
+        else
+            providerOptions &= ~QFileIconProvider::DontUseCustomDirectoryIcons;
+        iconProvider()->setOptions(providerOptions);
+    }
 }
 
 QFileDialog::Options QFileDialog::options() const
diff --git a/src/widgets/dialogs/qfiledialog.h b/src/widgets/dialogs/qfiledialog.h
index 2b276be8f1..6b12a00ae6 100644
--- a/src/widgets/dialogs/qfiledialog.h
+++ b/src/widgets/dialogs/qfiledialog.h
@@ -84,13 +84,14 @@ public:
 
     enum Option
     {
-        ShowDirsOnly          = 0x00000001,
-        DontResolveSymlinks   = 0x00000002,
-        DontConfirmOverwrite  = 0x00000004,
-        DontUseSheet          = 0x00000008,
-        DontUseNativeDialog   = 0x00000010,
-        ReadOnly              = 0x00000020,
-        HideNameFilterDetails = 0x00000040
+        ShowDirsOnly                = 0x00000001,
+        DontResolveSymlinks         = 0x00000002,
+        DontConfirmOverwrite        = 0x00000004,
+        DontUseSheet                = 0x00000008,
+        DontUseNativeDialog         = 0x00000010,
+        ReadOnly                    = 0x00000020,
+        HideNameFilterDetails       = 0x00000040,
+        DontUseCustomDirectoryIcons = 0x00000080
     };
     Q_DECLARE_FLAGS(Options, Option)
 
diff --git a/src/widgets/itemviews/qfileiconprovider.cpp b/src/widgets/itemviews/qfileiconprovider.cpp
index b435639390..f03d9fb81b 100644
--- a/src/widgets/itemviews/qfileiconprovider.cpp
+++ b/src/widgets/itemviews/qfileiconprovider.cpp
@@ -83,6 +83,16 @@ QT_BEGIN_NAMESPACE
   \value File
 */
 
+
+/*!
+    \enum QFileIconProvider::Option
+    \since 5.2
+
+    \value DontUseCustomDirectoryIcons Always use the default directory icon.
+    Some platforms allow the user to set a different icon. Custom icon lookup
+    cause a big performance impact over network or removable drives.
+*/
+
 class QFileIconProviderPrivate
 {
     Q_DECLARE_PUBLIC(QFileIconProvider)
@@ -94,6 +104,7 @@ public:
 
     QFileIconProvider *q_ptr;
     const QString homePath;
+    QFileIconProvider::Options options;
 
 private:
     mutable QIcon file;
@@ -193,6 +204,31 @@ QFileIconProvider::~QFileIconProvider()
 }
 
 /*!
+    \since 5.2
+    Sets \a options that affect the icon provider.
+    \sa options()
+*/
+
+void QFileIconProvider::setOptions(QFileIconProvider::Options options)
+{
+    Q_D(QFileIconProvider);
+    d->options = options;
+}
+
+/*!
+    \since 5.2
+    Returns all the options that affect the icon provider.
+    By default, all options are disabled.
+    \sa setOptions()
+*/
+
+QFileIconProvider::Options QFileIconProvider::options() const
+{
+    Q_D(const QFileIconProvider);
+    return d->options;
+}
+
+/*!
   Returns an icon set for the given \a type.
 */
 
@@ -228,6 +264,7 @@ static bool isCacheable(const QFileInfo &fi)
 #ifdef Q_OS_WIN
     // On windows it's faster to just look at the file extensions. QTBUG-13182
     const QString fileExtension = fi.suffix();
+    // Will return false for .exe, .lnk and .ico extensions
     return fileExtension.compare(QLatin1String("exe"), Qt::CaseInsensitive) &&
            fileExtension.compare(QLatin1String("lnk"), Qt::CaseInsensitive) &&
            fileExtension.compare(QLatin1String("ico"), Qt::CaseInsensitive);
@@ -247,7 +284,6 @@ QIcon QFileIconProviderPrivate::getIcon(const QFileInfo &fi) const
     if (sizes.isEmpty())
         return retIcon;
 
-    const QString fileExtension = fi.suffix().toUpper();
     const QString keyBase = QLatin1String("qt_.") + fi.suffix().toUpper();
 
     bool cacheable = isCacheable(fi);
@@ -269,8 +305,12 @@ QIcon QFileIconProviderPrivate::getIcon(const QFileInfo &fi) const
         }
     }
 
+    QPlatformTheme::IconOptions iconOptions;
+    if (options & QFileIconProvider::DontUseCustomDirectoryIcons)
+        iconOptions |= QPlatformTheme::DontUseCustomDirectoryIcons;
+
     Q_FOREACH (int size, sizes) {
-        QPixmap pixmap = theme->fileIconPixmap(fi, QSizeF(size, size));
+        QPixmap pixmap = theme->fileIconPixmap(fi, QSizeF(size, size), iconOptions);
         if (!pixmap.isNull()) {
             retIcon.addPixmap(pixmap);
             if (cacheable)
diff --git a/src/widgets/itemviews/qfileiconprovider.h b/src/widgets/itemviews/qfileiconprovider.h
index cac135fe71..ed270619ed 100644
--- a/src/widgets/itemviews/qfileiconprovider.h
+++ b/src/widgets/itemviews/qfileiconprovider.h
@@ -59,10 +59,19 @@ public:
     QFileIconProvider();
     virtual ~QFileIconProvider();
     enum IconType { Computer, Desktop, Trashcan, Network, Drive, Folder, File };
+
+    enum Option {
+        DontUseCustomDirectoryIcons = 0x00000001
+    };
+    Q_DECLARE_FLAGS(Options, Option)
+
     virtual QIcon icon(IconType type) const;
     virtual QIcon icon(const QFileInfo &info) const;
     virtual QString type(const QFileInfo &info) const;
 
+    void setOptions(Options options);
+    Options options() const;
+
 private:
     Q_DECLARE_PRIVATE(QFileIconProvider)
     QScopedPointer<QFileIconProviderPrivate> d_ptr;
@@ -71,6 +80,8 @@ private:
 
 #endif // QT_NO_FILEICONPROVIDER
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(QFileIconProvider::Options)
+
 QT_END_NAMESPACE
 
 #endif // QFILEICONPROVIDER_H
diff --git a/tests/manual/dialogs/filedialogpanel.cpp b/tests/manual/dialogs/filedialogpanel.cpp
index 69e25e753a..dbb2e379b2 100644
--- a/tests/manual/dialogs/filedialogpanel.cpp
+++ b/tests/manual/dialogs/filedialogpanel.cpp
@@ -154,6 +154,7 @@ FileDialogPanel::FileDialogPanel(QWidget *parent)
     , m_nameFilterDetailsVisible(new QCheckBox(tr("Name filter details visible")))
     , m_resolveSymLinks(new QCheckBox(tr("Resolve symlinks")))
     , m_native(new QCheckBox(tr("Use native dialog")))
+    , m_customDirIcons(new QCheckBox(tr("Don't use custom directory icons")))
     , m_acceptMode(createCombo(this, acceptModeComboData, sizeof(acceptModeComboData)/sizeof(ComboData)))
     , m_fileMode(createCombo(this, fileModeComboData, sizeof(fileModeComboData)/sizeof(ComboData)))
     , m_viewMode(createCombo(this, viewModeComboData, sizeof(viewModeComboData)/sizeof(ComboData)))
@@ -178,6 +179,7 @@ FileDialogPanel::FileDialogPanel(QWidget *parent)
     optionsLayout->addRow(m_nameFilterDetailsVisible);
     optionsLayout->addRow(m_resolveSymLinks);
     optionsLayout->addRow(m_readOnly);
+    optionsLayout->addRow(m_customDirIcons);
 
     // Files
     QGroupBox *filesGroupBox = new QGroupBox(tr("Files / Filters"));
@@ -322,6 +324,8 @@ QFileDialog::Options FileDialogPanel::options() const
         result |= QFileDialog::DontConfirmOverwrite;
     if (!m_native->isChecked())
         result |= QFileDialog::DontUseNativeDialog;
+    if (!m_customDirIcons->isChecked())
+        result |= QFileDialog::DontUseCustomDirectoryIcons;
     return result;
 }
 
@@ -454,6 +458,7 @@ void FileDialogPanel::restoreDefaults()
     m_resolveSymLinks->setChecked(d.resolveSymlinks());
     m_readOnly->setChecked(d.isReadOnly());
     m_native->setChecked(true);
+    m_customDirIcons->setChecked(d.testOption(QFileDialog::DontUseCustomDirectoryIcons));
     m_directory->setText(QDir::homePath());
     m_defaultSuffix->setText(QLatin1String("txt"));
     m_nameFilters->setPlainText(QLatin1String("Any files (*)\nImage files (*.png *.xpm *.jpg)\nText files (*.txt)"));
diff --git a/tests/manual/dialogs/filedialogpanel.h b/tests/manual/dialogs/filedialogpanel.h
index 601fb7fc51..ce99836467 100644
--- a/tests/manual/dialogs/filedialogpanel.h
+++ b/tests/manual/dialogs/filedialogpanel.h
@@ -92,6 +92,7 @@ private:
     QCheckBox *m_nameFilterDetailsVisible;
     QCheckBox *m_resolveSymLinks;
     QCheckBox *m_native;
+    QCheckBox *m_customDirIcons;
     QComboBox *m_acceptMode;
     QComboBox *m_fileMode;
     QComboBox *m_viewMode;