itemactions: Add context menu actions to hide and unhide files using .hidden

Summary:
This patch introduces context menu actions that allow users to hide or unhide selected files by editing the .hidden file in their parent directories.

What this patch does:
- Implemented HideFileItemAction plugin based on KAbstractFileItemActionPlugin
- Plugin is disabled by default unless explicitly enabled in kservicemenurc via the hidefileitemaction key
- "Hide" action adds selected file names to the .hidden file, avoiding duplicates
- "Unhide" action removes selected file names from the .hidden file
- Action visibility logic:
	- If only visible or only hidden files are selected, only the relevant action is shown
	- If both are selected, both "Hide" and "Unhide" actions are shown
- Write permission checks ensure actions are disabled if the .hidden file cannot be modified
- Optimized redundant path computations by calculating parent directory and .hidden file paths once and reusing them

4 files changed, 220 insertions, 0 deletions

diff --git a/src/itemactions/CMakeLists.txt b/src/itemactions/CMakeLists.txt
index 6610b0e4a..cd196eb36 100644
--- a/src/itemactions/CMakeLists.txt
+++ b/src/itemactions/CMakeLists.txt
@@ -11,6 +11,16 @@ target_link_libraries(movetonewfolderitemaction
     KF6::KIOWidgets
     KF6::KIOFileWidgets)
 
+#hidefileitemaction plugin
+kcoreaddons_add_plugin(hidefileitemaction
+    SOURCES hidefileitemaction.cpp hidefileitemaction.h
+    INSTALL_NAMESPACE "kf6/kfileitemaction")
+
+target_link_libraries(hidefileitemaction
+    KF6::CoreAddons
+    KF6::I18n
+    KF6::KIOCore
+    KF6::KIOWidgets)
 
 if(NOT WIN32)
     # setfoldericon plugin
@@ -24,3 +34,4 @@ if(NOT WIN32)
         KF6::KIOCore
         KF6::KIOWidgets)
 endif()
+
diff --git a/src/itemactions/hidefileitemaction.cpp b/src/itemactions/hidefileitemaction.cpp
new file mode 100644
index 000000000..b01117838
--- /dev/null
+++ b/src/itemactions/hidefileitemaction.cpp
@@ -0,0 +1,173 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Kostiantyn Korchuhanov <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "hidefileitemaction.h"
+#include "../dolphindebug.h"
+
+#ifdef QT_DBUS_LIB
+#include <KDirNotify>
+#endif
+#include <KConfigGroup>
+#include <KFileItem>
+#include <KFileItemListProperties>
+#include <KLocalizedString>
+#include <KPluginFactory>
+#include <KSharedConfig>
+
+#include <QAction>
+#include <QDir>
+#include <QFile>
+#include <QFileInfo>
+#include <QTextStream>
+#include <QUrl>
+
+K_PLUGIN_CLASS_WITH_JSON(HideFileItemAction, "hidefileitemaction.json");
+
+HideFileItemAction::HideFileItemAction(QObject *parent)
+    : KAbstractFileItemActionPlugin(parent)
+{
+}
+
+static bool pluginIsEnabled()
+{
+    KConfigGroup showGroup(KSharedConfig::openConfig(QStringLiteral("kservicemenurc")), QStringLiteral("Show"));
+    return showGroup.readEntry(QStringLiteral("hidefileitemaction"), false);
+}
+
+static QStringList readHiddenFileEntries(const QString &hiddenPath)
+{
+    QStringList entriesNames;
+    QFile readHiddenFile(hiddenPath);
+    if (readHiddenFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        QTextStream in(&readHiddenFile);
+        while (!in.atEnd()) {
+            entriesNames.append(in.readLine());
+        }
+    }
+    return entriesNames;
+}
+
+static bool fileAlreadyHidden(const KFileItem &item)
+{
+    QString fileName = item.name();
+    QString parentPath = QFileInfo(item.localPath()).absolutePath();
+    QString hiddenPath = QDir(parentPath).filePath(".hidden");
+
+    QStringList entriesNames = readHiddenFileEntries(hiddenPath);
+
+    return entriesNames.contains(fileName);
+}
+
+static void writeHiddenFileEntries(const QString &hiddenPath, const QStringList &entriesNames)
+{
+    QFile writeHiddenFile(hiddenPath);
+    if (writeHiddenFile.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate)) {
+        QTextStream out(&writeHiddenFile);
+        out << entriesNames.join("\n");
+    }
+}
+
+static void writeFileToHidden(const QString &hiddenPath, const QString &fileName)
+{
+    QStringList entriesNames = readHiddenFileEntries(hiddenPath);
+    if (!entriesNames.contains(fileName)) {
+        entriesNames.append(fileName);
+        writeHiddenFileEntries(hiddenPath, entriesNames);
+    }
+}
+
+static void deleteFileFromHidden(const QString &hiddenPath, const QString &fileName)
+{
+    QStringList entriesNames = readHiddenFileEntries(hiddenPath);
+    entriesNames.removeAll(fileName);
+    writeHiddenFileEntries(hiddenPath, entriesNames);
+}
+
+QList<QAction *> HideFileItemAction::actions(const KFileItemListProperties &fileItemInfos, QWidget *parentWidget)
+{
+    if (!pluginIsEnabled()) {
+        return {};
+    }
+    const KFileItemList selectedItems = fileItemInfos.items();
+    if (selectedItems.isEmpty()) {
+        return {};
+    }
+
+    const QUrl parentFileUrl = selectedItems.first().url().adjusted(QUrl::RemoveFilename);
+    const QString parentFilePath = parentFileUrl.toLocalFile();
+    const QString hiddenFilePath = QDir(parentFilePath).filePath(".hidden");
+
+    for (const KFileItem &item : selectedItems) {
+        if (item.url().adjusted(QUrl::RemoveFilename).toLocalFile() != parentFilePath) {
+            return {};
+        }
+    }
+
+    QFileInfo parentFileInfo(parentFilePath);
+    QFileInfo hiddenFileInfo(hiddenFilePath);
+    const bool canWrite = parentFileInfo.isWritable() && (!hiddenFileInfo.exists() || hiddenFileInfo.isWritable());
+
+    QAction *hideFolder = new QAction(i18nc("@action:inmenu", "Hide"), parentWidget);
+    hideFolder->setIcon(QIcon::fromTheme("hide_table_row"));
+    hideFolder->setEnabled(canWrite);
+
+    connect(hideFolder, &QAction::triggered, this, [selectedItems, hiddenFilePath, parentFilePath]() {
+        for (const KFileItem &item : selectedItems) {
+            if (item.name() == ".hidden") {
+                continue;
+            }
+
+            QString fileName = item.name();
+            writeFileToHidden(hiddenFilePath, fileName);
+
+#ifdef QT_DBUS_LIB
+            org::kde::KDirNotify::emitFilesChanged({QUrl::fromLocalFile(parentFilePath)});
+#endif
+        }
+    });
+
+    QAction *unhideFolder = new QAction(i18nc("@action:inmenu", "Unhide"), parentWidget);
+    unhideFolder->setIcon(QIcon::fromTheme("view-visible"));
+    unhideFolder->setEnabled(canWrite);
+
+    connect(unhideFolder, &QAction::triggered, this, [selectedItems, hiddenFilePath, parentFilePath]() {
+        for (const KFileItem &item : selectedItems) {
+            if (item.name() == ".hidden") {
+                continue;
+            }
+
+            QString fileName = item.name();
+            deleteFileFromHidden(hiddenFilePath, fileName);
+
+#ifdef QT_DBUS_LIB
+            org::kde::KDirNotify::emitFilesChanged({QUrl::fromLocalFile(parentFilePath)});
+#endif
+        }
+    });
+
+    bool anyFileHidden = false;
+    bool anyFileVisible = false;
+    for (const KFileItem &item : selectedItems) {
+        if (fileAlreadyHidden(item)) {
+            anyFileHidden = true;
+        } else {
+            anyFileVisible = true;
+        }
+        if (anyFileHidden && anyFileVisible) {
+            break;
+        }
+    }
+    if (anyFileHidden && anyFileVisible) {
+        return {hideFolder, unhideFolder};
+    }
+    if (anyFileVisible) {
+        return {hideFolder};
+    }
+    return {unhideFolder};
+}
+
+#include "hidefileitemaction.moc"
+#include "moc_hidefileitemaction.cpp"
diff --git a/src/itemactions/hidefileitemaction.h b/src/itemactions/hidefileitemaction.h
new file mode 100644
index 000000000..565f0d563
--- /dev/null
+++ b/src/itemactions/hidefileitemaction.h
@@ -0,0 +1,26 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Kostiantyn Korchuhanov <[email protected]>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef HIDEFILEITEMACTION_H
+#define HIDEFILEITEMACTION_H
+
+#include <KAbstractFileItemActionPlugin>
+#include <KFileItemListProperties>
+#include <QAction>
+#include <QList>
+#include <QWidget>
+
+class HideFileItemAction : public KAbstractFileItemActionPlugin
+{
+    Q_OBJECT
+
+public:
+    HideFileItemAction(QObject *parent);
+
+    QList<QAction *> actions(const KFileItemListProperties &fileItemInfos, QWidget *parentWidget) override;
+};
+
+#endif // HIDEFILEITEMACTION_H
diff --git a/src/itemactions/hidefileitemaction.json b/src/itemactions/hidefileitemaction.json
new file mode 100644
index 000000000..7b4627254
--- /dev/null
+++ b/src/itemactions/hidefileitemaction.json
@@ -0,0 +1,10 @@
+{
+    "KPlugin": {
+        "Icon": "hide_table_row",
+        "MimeTypes": [
+            "application/octet-stream"
+        ],
+        "Name": "Hide"
+    },
+    "X-KDE-Show-In-Submenu": true
+}