1 files changed, 114 insertions, 0 deletions
diff --git a/examples/demos/documentviewer/viewerfactory.py b/examples/demos/documentviewer/viewerfactory.py
new file mode 100644
index 000000000..ecae6770b
--- /dev/null
+++ b/examples/demos/documentviewer/viewerfactory.py
@@ -0,0 +1,114 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from enum import Enum, auto
+
+from PySide6.QtWidgets import (QMessageBox)
+from PySide6.QtCore import (QFileInfo, QMimeDatabase, QTimer)
+
+from txtviewer.txtviewer import TxtViewer
+from jsonviewer.jsonviewer import JsonViewer
+from pdfviewer.pdfviewer import PdfViewer
+
+
+class DefaultPolicy(Enum):
+    NeverDefault = auto()
+    DefaultToTxtViewer = auto()
+    DefaultToCustomViewer = auto()
+
+
+class ViewerFactory:
+
+    def __init__(self, displayWidget, mainWindow,
+                 policy=DefaultPolicy.NeverDefault):
+        self._viewers = {}
+        self._defaultViewer = None
+        self._defaultWarning = True
+        self._defaultPolicy = policy
+        self._displayWidget = displayWidget
+        self._mainWindow = mainWindow
+        self._mimeTypes = []
+        for v in [PdfViewer(), JsonViewer(), TxtViewer()]:
+            self._viewers[v.viewerName()] = v
+            if v.isDefaultViewer():
+                self._defaultViewer = v
+
+    def defaultPolicy(self):
+        return self._defaultPolicy
+
+    def setDefaultPolicy(self, policy):
+        self._defaultPolicy = policy
+
+    def defaultWarning(self):
+        return self._defaultWarning
+
+    def setDefaultWarning(self, on):
+        self._defaultWarning = on
+
+    def viewer(self, file):
+        info = QFileInfo(file)
+        db = QMimeDatabase()
+        mimeType = db.mimeTypeForFile(info)
+
+        viewer = self.viewerForMimeType(mimeType)
+        if not viewer:
+            print(f"Mime type {mimeType.name()} not supported.")
+            return None
+
+        viewer.init(file, self._displayWidget, self._mainWindow)
+        return viewer
+
+    def viewerNames(self, showDefault=False):
+        if not showDefault:
+            return self._viewers.keys()
+
+        list = []
+        for name, viewer in self._viewers.items():
+            if ((self._defaultViewer and viewer.isDefaultViewer())
+                    or (not self._defaultViewer and name == "TxtViewer")):
+                name += "(default)"
+            list.append(name)
+        return list
+
+    def viewers(self):
+        return self._viewers.values()
+
+    def findViewer(self, viewerName):
+        for viewer in self.viewers():
+            if viewer.viewerName() == viewerName:
+                return viewer
+        print(f"Plugin {viewerName} not loaded.")
+        return None
+
+    def viewerForMimeType(self, mimeType):
+        for viewer in self.viewers():
+            for type in viewer.supportedMimeTypes():
+                if mimeType.inherits(type):
+                    return viewer
+
+        viewer = self.defaultViewer()
+
+        if self._defaultWarning:
+            mbox = QMessageBox()
+            mbox.setIcon(QMessageBox.Warning)
+            name = mimeType.name()
+            viewer_name = viewer.viewerName()
+            m = f"Mime type {name} not supported. Falling back to {viewer_name}."
+            mbox.setText(m)
+            mbox.setStandardButtons(QMessageBox.Ok)
+            QTimer.singleShot(8000, mbox.close)
+            mbox.exec()
+        return viewer
+
+    def defaultViewer(self):
+        if self._defaultPolicy == DefaultPolicy.NeverDefault:
+            return None
+        if self._defaultPolicy == DefaultPolicy.DefaultToCustomViewer and self._defaultViewer:
+            return self._defaultViewer
+        return self.findViewer("TxtViewer")
+
+    def supportedMimeTypes(self):
+        if not self._mimeTypes:
+            for viewer in self.viewers():
+                self._mimeTypes.extend(viewer.supportedMimeTypes())
+        return self._mimeTypes