1 files changed, 159 insertions, 0 deletions
diff --git a/examples/demos/documentviewer/recentfiles.py b/examples/demos/documentviewer/recentfiles.py
new file mode 100644
index 000000000..fdfc56d40
--- /dev/null
+++ b/examples/demos/documentviewer/recentfiles.py
@@ -0,0 +1,159 @@
+# Copyright (C) 2023 The Qt Company Ltd.
+# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+from enum import Enum, auto
+
+from PySide6.QtCore import QFileInfo, QObject, QSettings, Signal, Slot
+
+
+DEFAULT_MAX_FILES = 10
+
+
+# Test if file exists and can be opened
+def testFileAccess(fileName):
+    return QFileInfo(fileName).isReadable()
+
+
+class RemoveReason(Enum):
+    Other = auto()
+    Duplicate = auto()
+
+
+class EmitPolicy(Enum):
+    EmitWhenChanged = auto(),
+    NeverEmit = auto()
+
+
+s_maxFiles = "maxFiles"
+s_openMode = "openMode"
+s_fileNames = "fileNames"
+s_file = "file"
+
+
+class RecentFiles(QObject):
+
+    countChanged = Signal(int)
+    changed = Signal()
+
+    def __init__(self, parent=None):
+        super().__init__(parent)
+        self._maxFiles = DEFAULT_MAX_FILES
+        self._files = []
+
+    # Access to QStringList member functions
+    def recentFiles(self):
+        return self._files
+
+    def isEmpty(self):
+        return not self._files
+
+    # Properties
+    def maxFiles(self):
+        return self._maxFiles
+
+    def setMaxFiles(self, maxFiles):
+        self._maxFiles = maxFiles
+
+    def addFile(self, fileName):
+        self._addFile(fileName, EmitPolicy.EmitWhenChanged)
+
+    def removeFile(self, fileName):
+        idx = self._files.find(fileName)
+        self._removeFile(idx, RemoveReason.Other)
+
+    @Slot()
+    def clear(self):
+        if self.isEmpty():
+            return
+        self._files.clear()
+        self.countChanged.emit(0)
+
+    def _addFile(self, fileName, policy):
+        if not testFileAccess(fileName):
+            return
+
+        # Remember size, as cleanup can result in a change without size change
+        c = len(self._files)
+
+        # Clean dangling and duplicate files
+        i = 0
+        while i < len(self._files):
+            file = self._files[i]
+            if not testFileAccess(file):
+                self._removeFile(file, RemoveReason.Other)
+            elif file == fileName:
+                self._removeFile(file, RemoveReason.Duplicate)
+            else:
+                i += 1
+
+        # Cut tail
+        while len(self._files) > self._maxFiles:
+            self.removeFile((len(self._files) - 1), RemoveReason.Other)
+
+        self._files.insert(0, fileName)
+
+        if policy == EmitPolicy.NeverEmit:
+            return
+
+        if policy == EmitPolicy.EmitWhenChanged:
+            self.changed.emit()
+            if c != len(self._files):
+                self.countChanged.emit(len(self._files))
+
+    @Slot(list)
+    def addFiles(self, files):
+        if files.isEmpty():
+            return
+
+        if len(files) == 1:
+            self.addFile(files[0])
+            return
+
+        c = len(self._files)
+
+        for file in files:
+            self.addFile(file, EmitPolicy.NeverEmit)
+
+        self.changed.emit()
+        if len(self._files) != c:
+            self.countChanged.emit(len(self._files))
+
+    def _removeFile(self, p, reason):
+        index = p
+        if isinstance(p, str):
+            index = self._files.index(p) if p in self._files else -1
+        if index < 0 or index >= len(self._files):
+            return
+        del self._files[index]
+
+        # No emit for duplicate removal, add emits changed later.
+        if reason != RemoveReason.Duplicate:
+            self.changed.emit()
+
+    @Slot(QSettings, str)
+    def saveSettings(self, settings, key):
+        settings.beginGroup(key)
+        settings.setValue(s_maxFiles, self.maxFiles())
+        if self._files:
+            settings.beginWriteArray(s_fileNames, len(self._files))
+            for index, file in enumerate(self._files):
+                settings.setArrayIndex(index)
+                settings.setValue(s_file, file)
+            settings.endArray()
+        settings.endGroup()
+
+    @Slot(QSettings, str)
+    def restoreFromSettings(self, settings, key):
+        settings.beginGroup(key)
+        self.setMaxFiles(settings.value(s_maxFiles, DEFAULT_MAX_FILES, int))
+        self._files.clear()  # clear list without emitting
+        numberFiles = settings.beginReadArray(s_fileNames)
+        for index in range(0, numberFiles):
+            settings.setArrayIndex(index)
+            absoluteFilePath = settings.value(s_file)
+            self._addFile(absoluteFilePath, EmitPolicy.NeverEmit)
+        settings.endArray()
+        settings.endGroup()
+        if self._files:
+            self.changed.emit()
+        return True