Enable native Linux editor input and loopback MCP

CodenameOne/src/com/codename1/ui/TextInputClient.java

@@ -38,6 +38,15 @@
 /// All offsets exchanged with the platform are UTF-16 character indices. All callbacks are delivered on
 /// the EDT.
 public interface TextInputClient {
+    /// Optional contract for clients that can restore a canceled composition, including rich text
+    /// attributes and undo state. Ports may restore text and selection for older clients; rich editors
+    /// should implement this contract to restore their complete pre-composition state.
+    interface CompositionCancellation {
+        /// Restores the text, selection and attributes from before composition without recording an
+        /// undo entry. Does nothing when no composition is active.
+        void cancelComposing();
+    }
+
     /// Key command: move / extend to the left.
     int KEY_LEFT = 1;
     /// Key command: move / extend to the right.

CodenameOne/src/com/codename1/ui/editor/EditorView.java

@@ -46,7 +46,7 @@
 /// This class provides the shared editing behavior. Feature layers (syntax highlighting, the gutter,
 /// styled rich text) subclass it and override `#paintContent(Graphics, int, int, int, int)` and the
 /// document/measurement hooks.
-public class EditorView extends Component implements TextInputClient, com.codename1.ui.TextInputGeometry.Provider {
+public class EditorView extends Component implements TextInputClient, TextInputClient.CompositionCancellation, com.codename1.ui.TextInputGeometry.Provider {
     private EditorHost host;
     private final boolean codeMode;
     private EditorDocument doc = new EditorDocument();
@@ -60,6 +60,8 @@ public class EditorView extends Component implements TextInputClient, com.codena
     // pre-composition snapshot so the finalized composition forms a single undo unit
     private String composingBaseRemoved;
     private Object composingBeforeState;
+    private int composingBeforeCaret;
+    private int composingBeforeAnchor;
     private boolean editable = true;
 
     private int scrollY;
@@ -1900,6 +1902,8 @@ public void setComposingText(String text, int relativeCaret) {
             // commitText / finishComposing; intermediate compose updates are never recorded
             composingBaseRemoved = doc.substring(start, end);
             composingBeforeState = captureDocumentState();
+            composingBeforeCaret = caret;
+            composingBeforeAnchor = anchor;
         }
         String removed = doc.substring(start, end);
         doc.delete(start, end);
@@ -1924,6 +1928,25 @@ public void setComposingText(String text, int relativeCaret) {
         }
     }
 
+    @Override
+    public void cancelComposing() {
+        if (composingStart < 0) {
+            return;
+        }
+        Object before = composingBeforeState;
+        int oldCaret = composingBeforeCaret;
+        int oldAnchor = composingBeforeAnchor;
+        replaceRange(composingStart, composingEnd,
+                composingBaseRemoved == null ? "" : composingBaseRemoved, false);
+        restoreDocumentState(before);
+        caret = doc.clamp(oldCaret);
+        anchor = oldAnchor < 0 ? -1 : doc.clamp(oldAnchor);
+        invalidateLayout();
+        scrollCaretVisible();
+        pushInputState();
+        repaint();
+    }
+
     @Override
     public void finishComposing() {
         if (composingStart >= 0) {

Ports/LinuxPort/nativeSources/cn1_linux_desktopwindow.c

@@ -135,6 +135,11 @@ CN1Graphics* cn1LinuxDesktopGraphics(int slot) {
     return &w->g;
 }
 
+GtkWidget* cn1LinuxDesktopDrawingArea(int slot) {
+    CN1LinuxWindow* w = slotAt(slot);
+    return w == 0 ? 0 : w->drawingArea;
+}
+
 GtkWidget* cn1LinuxDesktopWidget(int slot) {
     CN1LinuxWindow* w = slotAt(slot);
     return w == 0 ? 0 : w->window;
@@ -432,6 +437,9 @@ static gboolean cn1DesktopOnKey(GtkWidget* widget, GdkEventKey* e, gpointer data
             return FALSE;
         }
     }
+    if (cn1LinuxTextInputFilter((int) (w - cn1DesktopWindows), e)) {
+        return TRUE;
+    }
     /* Same mapping the main window uses: GDK encodes many Unicode keyvals
      * differently from their code point, so a raw keyval gives the wrong key code
      * for anything outside ASCII. Navigation keys have no Unicode mapping and fall
@@ -730,6 +738,8 @@ static void cn1DesktopCreateOnMain(void* arg) {
 
     gtk_container_add(GTK_CONTAINER(w->overlay), w->drawingArea);
     gtk_overlay_add_overlay(GTK_OVERLAY(w->overlay), w->fixed);
+    /* Empty peer-layer space must reach the canvas, as in the main window. */
+    gtk_overlay_set_overlay_pass_through(GTK_OVERLAY(w->overlay), w->fixed, TRUE);
     gtk_container_add(GTK_CONTAINER(w->window), w->overlay);
 
     gtk_widget_add_events(w->drawingArea,

Ports/LinuxPort/nativeSources/cn1_linux_edit.c

@@ -209,7 +209,8 @@ JAVA_OBJECT com_codename1_impl_linux_LinuxNative_editGetText___long_R_java_lang_
         return JAVA_NULL;
     }
     pthread_mutex_lock(&e->lock);
-    result = newStringFromCString(threadStateData, e->text ? e->text : "");
+    result = newStringFromUtf8Len(threadStateData, e->text ? e->text : "",
+            e->text ? (int) strlen(e->text) : 0);
     pthread_mutex_unlock(&e->lock);
     return result;
 }

Ports/LinuxPort/nativeSources/cn1_linux_gfx.h

@@ -132,6 +132,9 @@ void cn1LinuxOverlayRemove(int slot, GtkWidget* w);
 
 /* The top-level GtkWindow (NULL in headless mode). */
 GtkWidget* cn1LinuxWindowWidget(void);
+GtkWidget* cn1LinuxTextCanvas(int slot);
+GtkWidget* cn1LinuxDesktopDrawingArea(int slot);
+gboolean cn1LinuxTextInputFilter(int slot, GdkEventKey* event);
 
 /* Additional desktop windows (cn1_linux_desktopwindow.c). A secondary window
  * carries its own GtkWindow, drawing area, peer overlay and cairo back buffer;

Ports/LinuxPort/nativeSources/cn1_linux_services.c

@@ -210,7 +210,7 @@ JAVA_OBJECT com_codename1_impl_linux_LinuxNative_clipboardGetText___R_java_lang_
     JAVA_OBJECT result;
     r.text = NULL;
     cn1LinuxRunOnMainAndWait(cn1ClipGetTextOnMain, &r);
-    result = r.text ? newStringFromCString(threadStateData, r.text) : JAVA_NULL;
+    result = r.text ? newStringFromUtf8Len(threadStateData, r.text, (int) strlen(r.text)) : JAVA_NULL;
     if (r.text) {
         g_free(r.text);
     }