Fix #41: add write accessibility API

3 files changed, 94 insertions, 1 deletions

diff --git a/src/uca-camera.c b/src/uca-camera.c
index 46e7cb7..fce3d12 100644
--- a/src/uca-camera.c
+++ b/src/uca-camera.c
@@ -76,6 +76,11 @@ GQuark uca_unit_quark ()
     return g_quark_from_static_string ("uca-unit-quark");
 }
 
+GQuark uca_writable_quark ()
+{
+    return g_quark_from_static_string ("uca-writable-quark");
+}
+
 enum {
     LAST_SIGNAL
 };
@@ -1050,3 +1055,53 @@ uca_camera_get_unit (UcaCamera *camera,
     return data == NULL ? UCA_UNIT_NA : GPOINTER_TO_INT (data);
 }
 
+/**
+ * uca_camera_set_writable:
+ * @camera: A #UcaCamera object
+ * @prop_name: Name of property
+ * @writable: %TRUE if property can be written during acquisition
+ *
+ * Sets a flag that defines if @prop_name can be written during an acquisition.
+ *
+ * Since: 1.6
+ */
+void
+uca_camera_set_writable (UcaCamera *camera,
+                         const gchar *prop_name,
+                         gboolean writable)
+{
+    GParamSpec *pspec;
+
+    pspec = get_param_spec_by_name (camera, prop_name);
+
+    if (pspec != NULL) {
+        if (g_param_spec_get_qdata (pspec, UCA_WRITABLE_QUARK) != NULL)
+            g_warning ("::%s is already fixed", pspec->name);
+        else
+            g_param_spec_set_qdata (pspec, UCA_WRITABLE_QUARK, GINT_TO_POINTER (writable));
+    }
+}
+
+/**
+ * uca_camera_is_writable_during_acquisition:
+ * @camera: A #UcaCamera object
+ * @prop_name: Name of property
+ *
+ * Check if @prop_name can be written at run-time. This is %FALSE if the
+ * property is read-only, if uca_camera_set_writable() has not been called or
+ * uca_camera_set_writable() was called with %FALSE.
+ *
+ * Returns: %TRUE if the property can be written at acquisition time.
+ * Since: 1.6
+ */
+gboolean
+uca_camera_is_writable_during_acquisition (UcaCamera *camera,
+                                           const gchar *prop_name)
+{
+    GParamSpec *pspec;
+
+    pspec = get_param_spec_by_name (camera, prop_name);
+
+    return (pspec->flags & G_PARAM_WRITABLE) &&
+            g_param_spec_get_qdata (pspec, UCA_WRITABLE_QUARK);
+}
diff --git a/src/uca-camera.h b/src/uca-camera.h
index f4030d6..d958870 100644
--- a/src/uca-camera.h
+++ b/src/uca-camera.h
@@ -31,9 +31,11 @@ G_BEGIN_DECLS
 
 #define UCA_CAMERA_ERROR    uca_camera_error_quark()
 #define UCA_UNIT_QUARK      uca_unit_quark()
+#define UCA_WRITABLE_QUARK  uca_writable_quark()
 
 GQuark uca_camera_error_quark(void);
 GQuark uca_unit_quark(void);
+GQuark uca_writable_quark(void);
 
 typedef enum {
     UCA_CAMERA_ERROR_NOT_FOUND,
@@ -162,6 +164,13 @@ void        uca_camera_register_unit    (UcaCamera          *camera,
                                          UcaUnit             unit);
 UcaUnit     uca_camera_get_unit         (UcaCamera          *camera,
                                          const gchar        *prop_name);
+void        uca_camera_set_writable     (UcaCamera          *camera,
+                                         const gchar        *prop_name,
+                                         gboolean            writable);
+gboolean    uca_camera_is_writable_during_acquisition
+                                        (UcaCamera          *camera,
+                                         const gchar        *prop_name);
+
 
 GType uca_camera_get_type(void);
 
diff --git a/test/test-mock.c b/test/test-mock.c
index 16ef30c..c0acc9c 100644
--- a/test/test-mock.c
+++ b/test/test-mock.c
@@ -225,6 +225,34 @@ test_overwriting_units (Fixture *fixture, gconstpointer data)
     uca_camera_register_unit (fixture->camera, "sensor-width", UCA_UNIT_PIXEL);
 }
 
+static void
+test_can_be_written (Fixture *fixture, gconstpointer data)
+{
+    GError *error = NULL;
+
+    /* read-only cannot ever be written */
+    g_assert (!uca_camera_is_writable_during_acquisition (fixture->camera, "name"));
+
+    /* unset properties cannot be written */
+    g_assert (!uca_camera_is_writable_during_acquisition (fixture->camera, "roi-width"));
+
+    /* check trivial cases */
+    uca_camera_set_writable (fixture->camera, "roi-width", TRUE);
+    g_assert (uca_camera_is_writable_during_acquisition (fixture->camera, "roi-width"));
+
+    uca_camera_set_writable (fixture->camera, "roi-height", FALSE);
+    g_assert (!uca_camera_is_writable_during_acquisition (fixture->camera, "roi-height"));
+
+    /* Now, do a real test */
+    uca_camera_set_writable (fixture->camera, "roi-height", TRUE);
+    uca_camera_start_recording (fixture->camera, &error);
+    g_assert_no_error (error);
+
+    g_object_set (fixture->camera, "roi-height", 128, NULL);
+    uca_camera_stop_recording (fixture->camera, &error);
+    g_assert_no_error (error);
+}
+
 int main (int argc, char *argv[])
 {
     gsize n_tests;
@@ -251,7 +279,8 @@ int main (int argc, char *argv[])
         {"/properties/binnings", test_binnings_properties},
         {"/properties/frames-per-second", test_fps_property},
         {"/properties/units", test_property_units},
-        {"/properties/units/overwrite", test_overwriting_units}
+        {"/properties/units/overwrite", test_overwriting_units},
+        {"/properties/can-be-written", test_can_be_written},
     };
 
     n_tests = sizeof(tests) / sizeof(tests[0]);