Clipboard sync on new connection

Summary: Added a timestamp to track clipboard changes, so when a new device connects it will sync the most recently updated clipboard to both devices.

Reviewers: #kde_connect, albertvaka

Reviewed By: #kde_connect, albertvaka

Subscribers: albertvaka, sredman, kdeconnect

Tags: #kde_connect

Differential Revision: https://phabricator.kde.org/D22584

plugins/clipboard/clipboardlistener.cpp

@@ -38,16 +38,28 @@ void ClipboardListener::updateClipboard(QClipboard::Mode mode)
 
     QString content = clipboard->text();
 
-    if (content == currentContent) {
+    if (content == m_currentContent) {
         return;
     }
-    currentContent = content;
+    m_updateTimestamp = QDateTime::currentDateTime().toMSecsSinceEpoch();
+    m_currentContent = content;
 
     Q_EMIT clipboardChanged(content);
 }
 
+QString ClipboardListener::currentContent()
+{
+    return m_currentContent;
+}
+
+qint64 ClipboardListener::updateTimestamp(){
+
+    return m_updateTimestamp;
+}
+
 void ClipboardListener::setText(const QString& content)
 {
-    currentContent = content;
+    m_updateTimestamp = QDateTime::currentDateTime().toMSecsSinceEpoch();
+    m_currentContent = content;
     clipboard->setText(content);
 }

plugins/clipboard/clipboardlistener.h

@@ -21,6 +21,7 @@
 #ifndef CLIPBOARDLISTENER_H
 #define CLIPBOARDLISTENER_H
 
+#include <QDateTime>
 #include <QTimer>
 #include <QObject>
 #include <QClipboard>
@@ -35,7 +36,8 @@ class ClipboardListener : public QObject
 
 private:
     ClipboardListener();
-    QString currentContent;
+    QString m_currentContent;
+    qint64 m_updateTimestamp = 0;
     QClipboard* clipboard;
 #ifdef Q_OS_MAC
     QTimer m_clipboardMonitorTimer;
@@ -56,6 +58,9 @@ public:
 
     void setText(const QString& content);
 
+    QString currentContent();
+    qint64 updateTimestamp();
+
 Q_SIGNALS:
     void clipboardChanged(const QString& content);
 };

plugins/clipboard/clipboardplugin.cpp

@@ -35,17 +35,44 @@ ClipboardPlugin::ClipboardPlugin(QObject* parent, const QVariantList& args)
             this, &ClipboardPlugin::propagateClipboard);
 }
 
+void ClipboardPlugin::connected()
+{
+    sendConnectPacket();
+}
+
 void ClipboardPlugin::propagateClipboard(const QString& content)
 {
     NetworkPacket np(PACKET_TYPE_CLIPBOARD, {{QStringLiteral("content"), content}});
     sendPacket(np);
 }
 
+void ClipboardPlugin::sendConnectPacket()
+{
+    NetworkPacket np(PACKET_TYPE_CLIPBOARD_CONNECT, {
+        {QStringLiteral("content"), ClipboardListener::instance()->currentContent()},
+        {QStringLiteral("timestamp"), ClipboardListener::instance()->updateTimestamp()}
+    });
+    sendPacket(np);
+}
+
+
 bool ClipboardPlugin::receivePacket(const NetworkPacket& np)
 {
     QString content = np.get<QString>(QStringLiteral("content"));
-    ClipboardListener::instance()->setText(content);
-    return true;
+    if (np.type() == PACKET_TYPE_CLIPBOARD) {
+        ClipboardListener::instance()->setText(content);
+        return true;
+    } else if (np.type() == PACKET_TYPE_CLIPBOARD_CONNECT) {
+        qint64 packetTime = np.get<qint64>(QStringLiteral("timestamp"));
+        // If the packetTime is 0, it means the timestamp is unknown (so do nothing).
+        if (packetTime == 0 || packetTime < ClipboardListener::instance()->updateTimestamp()) {
+            return false;
+        }
+
+        ClipboardListener::instance()->setText(content);
+        return true;
+    }
+    return false;
 }
 
 #include "clipboardplugin.moc"

plugins/clipboard/clipboardplugin.h

@@ -27,8 +27,32 @@
 #include <core/kdeconnectplugin.h>
 
 Q_DECLARE_LOGGING_CATEGORY(KDECONNECT_PLUGIN_CLIPBOARD)
+
+/**
+ * Packet containing just clipboard contents, sent when a device updates its clipboard.
+ * <p>
+ * The body should look like so:
+ * {
+ * "content": "password"
+ * }
+ */
 #define PACKET_TYPE_CLIPBOARD QStringLiteral("kdeconnect.clipboard")
 
+/**
+ * Packet containing clipboard contents and a timestamp that the contents were last updated, sent
+ * on first connection
+ * <p>
+ * The timestamp is milliseconds since epoch. It can be 0, which indicates that the clipboard
+ * update time is currently unknown.
+ * <p>
+ * The body should look like so:
+ * {
+ * "timestamp": 542904563213,
+ * "content": "password"
+ * }
+ */
+#define PACKET_TYPE_CLIPBOARD_CONNECT QStringLiteral("kdeconnect.clipboard.connect")
+
 class ClipboardPlugin
     : public KdeConnectPlugin
 {
@@ -38,10 +62,10 @@ public:
     explicit ClipboardPlugin(QObject* parent, const QVariantList& args);
 
     bool receivePacket(const NetworkPacket& np) override;
-    void connected() override { }
-
+    void connected() override;
 private Q_SLOTS:
     void propagateClipboard(const QString& content);
+    void sendConnectPacket();
 
 };
 

plugins/clipboard/kdeconnect_clipboard.json

@@ -129,9 +129,9 @@
         "Website": "https://albertvaka.wordpress.com"
     },
     "X-KdeConnect-OutgoingPacketType": [
-        "kdeconnect.clipboard"
+        "kdeconnect.clipboard", "kdeconnect.clipboard.connect"
     ],
     "X-KdeConnect-SupportedPacketType": [
-        "kdeconnect.clipboard"
+        "kdeconnect.clipboard", "kdeconnect.clipboard.connect"
     ]
 }