GUACAMOLE-1204: Add support for declaring layer multi-touch capabilities.

src/common/common/surface.h

@@ -120,6 +120,12 @@ typedef struct guac_common_surface {
      */
     guac_socket* socket;
 
+    /**
+     * The number of simultaneous touches that this surface can accept, where 0
+     * indicates that the surface does not support touch events at all.
+     */
+    int touches;
+
     /**
      * The X coordinate of the upper-left corner of this layer, in pixels,
      * relative to its parent layer. This is only applicable to visible
@@ -486,5 +492,23 @@ void guac_common_surface_flush(guac_common_surface* surface);
 void guac_common_surface_dup(guac_common_surface* surface, guac_user* user,
         guac_socket* socket);
 
+/**
+ * Declares that the given surface should receive touch events. By default,
+ * surfaces are assumed to not expect touch events. This value is advisory, and
+ * the client is not required to honor the declared level of touch support.
+ * Implementations are expected to safely handle or ignore any received touch
+ * events, regardless of the level of touch support declared.  regardless of
+ * the level of touch support declared.
+ *
+ * @param surface
+ *     The surface to modify.
+ *
+ * @param touches
+ *     The number of simultaneous touches that this surface can accept, where 0
+ *     indicates that the surface does not support touch events at all.
+ */
+void guac_common_surface_set_multitouch(guac_common_surface* surface,
+        int touches);
+
 #endif
 

src/common/surface.c

@@ -103,6 +103,19 @@
  */
 #define GUAC_SURFACE_WEBP_BLOCK_SIZE 8
 
+void guac_common_surface_set_multitouch(guac_common_surface* surface,
+        int touches) {
+
+    pthread_mutex_lock(&surface->_lock);
+
+    surface->touches = touches;
+    guac_protocol_send_set_int(surface->socket, surface->layer,
+            GUAC_PROTOCOL_LAYER_PARAMETER_MULTI_TOUCH, touches);
+
+    pthread_mutex_unlock(&surface->_lock);
+
+}
+
 void guac_common_surface_move(guac_common_surface* surface, int x, int y) {
 
     pthread_mutex_lock(&surface->_lock);
@@ -1981,6 +1994,11 @@ void guac_common_surface_dup(guac_common_surface* surface, guac_user* user,
         guac_protocol_send_move(socket, surface->layer,
                 surface->parent, surface->x, surface->y, surface->z);
 
+        /* Synchronize multi-touch support level */
+        guac_protocol_send_set_int(surface->socket, surface->layer,
+                GUAC_PROTOCOL_LAYER_PARAMETER_MULTI_TOUCH,
+                surface->touches);
+
     }
 
     /* Sync size to new socket */

src/libguac/guacamole/protocol-constants.h

@@ -49,5 +49,20 @@
  */
 #define GUAC_PROTOCOL_BLOB_MAX_LENGTH 6048
 
+/**
+ * The name of the layer parameter defining the number of simultaneous points
+ * of contact supported by a layer. This parameter should be set to a non-zero
+ * value if the associated layer should receive touch events ("touch"
+ * instructions).
+ *
+ * This value specified for this parameter is advisory, and the client is not
+ * required to honor the declared level of touch support.  Implementations are
+ * expected to safely handle or ignore any received touch events, regardless of
+ * the level of touch support declared.
+ *
+ * @see guac_protocol_send_set_int()
+ */
+#define GUAC_PROTOCOL_LAYER_PARAMETER_MULTI_TOUCH "multi-touch"
+
 #endif
 

src/libguac/guacamole/protocol.h

@@ -271,6 +271,32 @@ int guac_protocol_send_ready(guac_socket* socket, const char* id);
 int guac_protocol_send_set(guac_socket* socket, const guac_layer* layer,
         const char* name, const char* value);
 
+/**
+ * Sends a set instruction over the given guac_socket connection. This function
+ * behavies identically to guac_protocol_send_set() except that the provided
+ * parameter value is an integer, rather than a string.
+ *
+ * If an error occurs sending the instruction, a non-zero value is
+ * returned, and guac_error is set appropriately.
+ *
+ * @param socket
+ *     The guac_socket connection to use.
+ *
+ * @param layer
+ *     The layer to set the parameter of.
+ *
+ * @param name
+ *     The name of the parameter to set.
+ *
+ * @param value
+ *     The value to set the parameter to.
+ *
+ * @return
+ *     Zero on success, non-zero on error.
+ */
+int guac_protocol_send_set_int(guac_socket* socket, const guac_layer* layer,
+        const char* name, int value);
+
 /**
  * Sends a select instruction over the given guac_socket connection.
  *

src/libguac/protocol.c

@@ -1057,6 +1057,26 @@ int guac_protocol_send_set(guac_socket* socket, const guac_layer* layer,
 
 }
 
+int guac_protocol_send_set_int(guac_socket* socket, const guac_layer* layer,
+        const char* name, int value) {
+
+    int ret_val;
+
+    guac_socket_instruction_begin(socket);
+    ret_val =
+           guac_socket_write_string(socket, "3.set,")
+        || __guac_socket_write_length_int(socket, layer->index)
+        || guac_socket_write_string(socket, ",")
+        || __guac_socket_write_length_string(socket, name)
+        || guac_socket_write_string(socket, ",")
+        || __guac_socket_write_length_int(socket, value)
+        || guac_socket_write_string(socket, ";");
+
+    guac_socket_instruction_end(socket);
+    return ret_val;
+
+}
+
 int guac_protocol_send_select(guac_socket* socket, const char* protocol) {
 
     int ret_val;