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>

4 files changed, 27 insertions, 7 deletions

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);