Add support for `OSC 4` and `OSC 104`

For managing the text color table.
The color table may be modified, but currently konsole still uses the unmodified table for display.

(cherry picked from commit 67099363)

src/Vt102Emulation.cpp

@@ -78,6 +78,10 @@ Vt102Emulation::Vt102Emulation()
     tokenData = QByteArray();
 
     _graphicsImages = std::map<int, QImage *>();
+
+    for (int i = 0; i < 256; i++) {
+        colorTable[i] = QColor();
+    }
 }
 
 Vt102Emulation::~Vt102Emulation()
@@ -753,6 +757,35 @@ void Vt102Emulation::processSessionAttributeRequest(int tokenSize)
             _currentScreen->setLineProperty(LINE_PROMPT_START, true);
         }
     }
+    if (attribute == 4) {
+        // RGB colors
+        QStringList params = value.split(QLatin1Char(';'));
+        for (int i = 0; i < params.length(); i += 2) {
+            if (params.length() == i + 1) {
+                return;
+            }
+            int c = params[i].toInt();
+            if (params[i + 1] == QLatin1String("?")) {
+                QColor color = colorTable[c];
+                if (!color.isValid()) {
+                    color = CharacterColor(COLOR_SPACE_256, c).color(ColorScheme::defaultTable);
+                }
+                reportColor(c, color);
+                return;
+            }
+            QColor col(params[1]);
+            colorTable[c] = col;
+        }
+        return;
+    }
+    if (attribute == 104) {
+        // RGB colors
+        QStringList params = value.split(QLatin1Char(';'));
+        for (int i = 0; i < params.length(); i++) {
+            int c = params[i].toInt();
+            colorTable[c] = QColor();
+        }
+    }
 
     if (value == QLatin1String("?")) {
         // pass terminator type indication here, because OSC response terminator
@@ -1574,6 +1607,22 @@ void Vt102Emulation::reportCellSize()
     sendString(tmp);
 }
 
+void Vt102Emulation::reportColor(int c, QColor color)
+{
+    char tmp[60];
+    snprintf(tmp,
+             sizeof(tmp),
+             "\033]4;%i;rgb:%02x%02x/%02x%02x/%02x%02x\007",
+             c,
+             color.red(),
+             color.red(),
+             color.green(),
+             color.green(),
+             color.blue(),
+             color.blue());
+    sendString(tmp);
+}
+
 void Vt102Emulation::reportSize()
 {
     char tmp[30];

src/Vt102Emulation.h

@@ -163,6 +163,7 @@ private:
     void reportPixelSize();
     void reportCellSize();
     void reportSize();
+    void reportColor(int c, QColor color);
     void reportTerminalParms(int p);
 
     // clears the screen and resizes it to the specified
@@ -195,6 +196,8 @@ private:
 
     bool _reportFocusEvents;
 
+    QColor colorTable[256];
+
     // Sixel:
 #define MAX_SIXEL_COLORS 256
 #define MAX_IMAGE_DIM 16384