GUACAMOLE-377: Migrate RDP to direct access of FreeRDP's GDI buffer.

src/protocols/rdp/gdi.c

@@ -18,7 +18,6 @@
  */
 
 #include "color.h"
-#include "guacamole/display.h"
 #include "rdp.h"
 #include "settings.h"
 
@@ -27,7 +26,9 @@
 #include <freerdp/gdi/gdi.h>
 #include <freerdp/graphics.h>
 #include <freerdp/primary.h>
+#include <guacamole/assert.h>
 #include <guacamole/client.h>
+#include <guacamole/display.h>
 #include <guacamole/protocol.h>
 #include <winpr/wtypes.h>
 
@@ -74,40 +75,63 @@ BOOL guac_rdp_gdi_surface_frame_marker(rdpContext* context, const SURFACE_FRAME_
 
 }
 
+BOOL guac_rdp_gdi_begin_paint(rdpContext* context) {
+
+    guac_client* client = ((rdp_freerdp_context*) context)->client;
+    guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
+    rdpGdi* gdi = context->gdi;
+
+    GUAC_ASSERT(rdp_client->current_paint == NULL);
+
+    guac_display_layer* default_layer =
+        guac_display_default_layer(rdp_client->display);
+
+    guac_display_layer_raw_context* current_paint =
+        guac_display_layer_open_raw(default_layer);
+    current_paint->buffer = gdi->primary_buffer;
+    current_paint->stride = gdi->stride;
+    guac_rect_init(&current_paint->bounds, 0, 0, gdi->width, gdi->height);
+
+    rdp_client->current_paint = current_paint;
+
+    return TRUE;
+
+}
+
 BOOL guac_rdp_gdi_end_paint(rdpContext* context) {
 
     guac_client* client = ((rdp_freerdp_context*) context)->client;
     guac_rdp_client* rdp_client = (guac_rdp_client*) client->data;
     rdpGdi* gdi = context->gdi;
 
+    GUAC_ASSERT(rdp_client->current_paint != NULL);
+    guac_display_layer_raw_context* current_paint = rdp_client->current_paint;
+    rdp_client->current_paint = NULL;
+
+    guac_display_layer* default_layer =
+        guac_display_default_layer(rdp_client->display);
+
     /* Ignore paint if GDI output is suppressed */
     if (gdi->suppressOutput)
-        return TRUE;
+        goto paint_complete;
 
     /* Ignore paint if nothing has been done (empty rect) */
     if (gdi->primary->hdc->hwnd->invalid->null)
-        return TRUE;
+        goto paint_complete;
 
     INT32 x = gdi->primary->hdc->hwnd->invalid->x;
     INT32 y = gdi->primary->hdc->hwnd->invalid->y;
     UINT32 w = gdi->primary->hdc->hwnd->invalid->w;
     UINT32 h = gdi->primary->hdc->hwnd->invalid->h;
 
-    guac_display_layer* default_layer = guac_display_default_layer(rdp_client->display);
-    guac_display_layer_raw_context* dst_context = guac_display_layer_open_raw(default_layer);
-
     guac_rect dst_rect;
     guac_rect_init(&dst_rect, x, y, w, h);
-    guac_rect_constrain(&dst_rect, &dst_context->bounds);
-
-    guac_display_layer_raw_context_put(dst_context, &dst_rect,
-        GUAC_RECT_CONST_BUFFER(dst_rect, gdi->primary_buffer, gdi->stride, 4),
-        gdi->stride);
-
-    guac_rect_extend(&dst_context->dirty, &dst_rect);
+    guac_rect_constrain(&dst_rect, &current_paint->bounds);
 
-    guac_display_layer_close_raw(default_layer, dst_context);
+    guac_rect_extend(&current_paint->dirty, &dst_rect);
 
+paint_complete:
+    guac_display_layer_close_raw(default_layer, current_paint);
     return TRUE;
 
 }

src/protocols/rdp/gdi.h

@@ -71,6 +71,19 @@ BOOL guac_rdp_gdi_frame_marker(rdpContext* context, const FRAME_MARKER_ORDER* fr
  */
 BOOL guac_rdp_gdi_surface_frame_marker(rdpContext* context, const SURFACE_FRAME_MARKER* surface_frame_marker);
 
+/**
+ * Handler called when a paint operation is beginning. This function is
+ * expected to be called by the FreeRDP GDI implementation of RemoteFX when a
+ * new frame has started.
+ *
+ * @param context
+ *     The rdpContext associated with the current RDP session.
+ *
+ * @return
+ *     TRUE if successful, FALSE otherwise.
+ */
+BOOL guac_rdp_gdi_begin_paint(rdpContext* context);
+
 /**
  * Handler called when FreeRDP has finished performing updates to the backing
  * surface of its GDI (graphics) implementation.

src/protocols/rdp/rdp.c

@@ -214,6 +214,7 @@ static BOOL rdp_freerdp_pre_connect(freerdp* instance) {
 
     /* Set up GDI */
     GUAC_RDP_CONTEXT(instance)->update->DesktopResize = guac_rdp_gdi_desktop_resize;
+    GUAC_RDP_CONTEXT(instance)->update->BeginPaint = guac_rdp_gdi_begin_paint;
     GUAC_RDP_CONTEXT(instance)->update->EndPaint = guac_rdp_gdi_end_paint;
 
     GUAC_RDP_CONTEXT(instance)->update->SurfaceFrameMarker = guac_rdp_gdi_surface_frame_marker;
@@ -645,6 +646,18 @@ static int guac_rdp_handle_connection(guac_client* client) {
     freerdp_disconnect(rdp_inst);
     pthread_mutex_unlock(&(rdp_client->message_lock));
 
+    /* Any outstanding paint operation must have completed by now (we must do
+     * this before freeing FreeRDP's GDI as the guac_display will have a
+     * reference to the GDI's primary_buffer) */
+    if (rdp_client->current_paint) {
+        guac_display_layer_close_raw(guac_display_default_layer(rdp_client->display), rdp_client->current_paint);
+        rdp_client->current_paint = NULL;
+    }
+
+    /* Free display */
+    guac_display_free(rdp_client->display);
+    rdp_client->display = NULL;
+
     /* Clean up FreeRDP internal GDI implementation */
     gdi_free(rdp_inst);
 
@@ -663,10 +676,6 @@ static int guac_rdp_handle_connection(guac_client* client) {
     guac_rdp_keyboard_free(rdp_client->keyboard);
     rdp_client->keyboard = NULL;
 
-    /* Free display */
-    guac_display_free(rdp_client->display);
-    rdp_client->display = NULL;
-
     guac_rwlock_release_lock(&(rdp_client->lock));
 
     /* Client is now disconnected */

src/protocols/rdp/rdp.h

@@ -106,6 +106,13 @@ typedef struct guac_rdp_client {
      */
     guac_display_layer* current_surface;
 
+    /**
+     * The current, in-progress paint operation, as signalled by FreeRDP's
+     * "BeginPaint" callback. Once the paint operation is complete (signalled
+     * by "EndPaint"), this will be NULL.
+     */
+    guac_display_layer_raw_context* current_paint;
+
     /**
      * Whether the RDP server has reported that a new frame is in progress, and
      * we are now receiving updates relevant to that frame.