QtPlatformSupport: Add QAbstractFileIconEngine

Move the code from QtWidgets/QFileIconEngine into a new class with
virtuals in QtPlatformSupport so that platforms can reuse it.

Prototypically use the class in the Windows and macOS QPA plugins.

Remove QPlatformTheme::fileIconPixmap() and change the type
of the hint QPlatformTheme::IconPixmapSizes from QList<int>
to QList<QSize> so that it fits better with the icon code.

Change-Id: I580e936f3507218757565ca099272cd575b3a779
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

2 files changed, 37 insertions, 20 deletions

diff --git a/src/plugins/platforms/cocoa/qcocoatheme.h b/src/plugins/platforms/cocoa/qcocoatheme.h
index 282e527b0b..d47e620fbb 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.h
+++ b/src/plugins/platforms/cocoa/qcocoatheme.h
@@ -70,9 +70,7 @@ public:
     const QPalette *palette(Palette type = SystemPalette) const Q_DECL_OVERRIDE;
     const QFont *font(Font type = SystemFont) const Q_DECL_OVERRIDE;
     QPixmap standardPixmap(StandardPixmap sp, const QSizeF &size) const Q_DECL_OVERRIDE;
-    QPixmap fileIconPixmap(const QFileInfo &fileInfo,
-                           const QSizeF &size,
-                           QPlatformTheme::IconOptions options = 0) const Q_DECL_OVERRIDE;
+    QIcon fileIcon(const QFileInfo &fileInfo, QPlatformTheme::IconOptions options = 0) const override;
 
     QVariant themeHint(ThemeHint hint) const Q_DECL_OVERRIDE;
     QString standardButtonText(int button) const Q_DECL_OVERRIDE;
diff --git a/src/plugins/platforms/cocoa/qcocoatheme.mm b/src/plugins/platforms/cocoa/qcocoatheme.mm
index 01b654af68..3a3d634f5a 100644
--- a/src/plugins/platforms/cocoa/qcocoatheme.mm
+++ b/src/plugins/platforms/cocoa/qcocoatheme.mm
@@ -58,6 +58,7 @@
 #include <QtGui/private/qguiapplication_p.h>
 #include <QtGui/qpainter.h>
 #include <QtPlatformSupport/private/qcoretextfontdatabase_p.h>
+#include <QtPlatformSupport/private/qabstractfileiconengine_p.h>
 #include <qpa/qplatformintegration.h>
 #include <qpa/qplatformnativeinterface.h>
 
@@ -274,16 +275,41 @@ QPixmap QCocoaTheme::standardPixmap(StandardPixmap sp, const QSizeF &size) const
     return QPlatformTheme::standardPixmap(sp, size);
 }
 
-QPixmap QCocoaTheme::fileIconPixmap(const QFileInfo &fileInfo, const QSizeF &size,
-                                    QPlatformTheme::IconOptions iconOptions) const
+class QCocoaFileIconEngine : public QAbstractFileIconEngine
 {
-    Q_UNUSED(iconOptions);
-    QMacAutoReleasePool pool;
+public:
+    explicit QCocoaFileIconEngine(const QFileInfo &info,
+                                  QPlatformTheme::IconOptions opts) :
+        QAbstractFileIconEngine(info, opts) {}
+
+    static QList<QSize> availableIconSizes()
+    {
+        const qreal devicePixelRatio = qGuiApp->devicePixelRatio();
+        const int sizes[] = {
+            qRound(16 * devicePixelRatio), qRound(32 * devicePixelRatio),
+            qRound(64 * devicePixelRatio), qRound(128 * devicePixelRatio)
+        };
+        return QAbstractFileIconEngine::toSizeList(sizes, sizes + sizeof(sizes) / sizeof(sizes[0]));
+    }
+
+    QList<QSize> availableSizes(QIcon::Mode = QIcon::Normal, QIcon::State = QIcon::Off) const override
+    { return QCocoaFileIconEngine::availableIconSizes(); }
 
-    NSImage *iconImage = [[NSWorkspace sharedWorkspace] iconForFile:QCFString::toNSString(fileInfo.canonicalFilePath())];
-    if (!iconImage)
-        return QPixmap();
-    return qt_mac_toQPixmap(iconImage, size);
+protected:
+    QPixmap filePixmap(const QSize &size, QIcon::Mode, QIcon::State) override
+    {
+        QMacAutoReleasePool pool;
+
+        NSImage *iconImage = [[NSWorkspace sharedWorkspace] iconForFile:QCFString::toNSString(fileInfo().canonicalFilePath())];
+        if (!iconImage)
+            return QPixmap();
+        return qt_mac_toQPixmap(iconImage, size);
+    }
+};
+
+QIcon QCocoaTheme::fileIcon(const QFileInfo &fileInfo, QPlatformTheme::IconOptions iconOptions) const
+{
+    return QIcon(new QCocoaFileIconEngine(fileInfo, iconOptions));
 }
 
 QVariant QCocoaTheme::themeHint(ThemeHint hint) const
@@ -298,15 +324,8 @@ QVariant QCocoaTheme::themeHint(ThemeHint hint) const
     case TabFocusBehavior:
         return QVariant([[NSApplication sharedApplication] isFullKeyboardAccessEnabled] ?
                     int(Qt::TabFocusAllControls) : int(Qt::TabFocusTextControls | Qt::TabFocusListControls));
-    case IconPixmapSizes: {
-        qreal devicePixelRatio = qGuiApp->devicePixelRatio();
-        QList<int> sizes;
-        sizes << 16 * devicePixelRatio
-              << 32 * devicePixelRatio
-              << 64 * devicePixelRatio
-              << 128 * devicePixelRatio;
-        return QVariant::fromValue(sizes);
-    }
+    case IconPixmapSizes:
+        return QVariant::fromValue(QCocoaFileIconEngine::availableIconSizes());
     case QPlatformTheme::PasswordMaskCharacter:
         return QVariant(QChar(kBulletUnicode));
     case QPlatformTheme::UiEffects: