refactor(pointing): Allow stopping event propagation

Allow input processors to return a special value if a given input event
should not be further processed/propagated.

Author: petejohanson

app/include/drivers/input_processor.h

@@ -13,6 +13,9 @@
 #include <zephyr/device.h>
 #include <zephyr/input/input.h>
 
+#define ZMK_INPUT_PROC_CONTINUE 0
+#define ZMK_INPUT_PROC_STOP 1
+
 struct zmk_input_processor_entry {
     const struct device *dev;
     uint32_t param1;

app/src/pointing/input_listener.c

@@ -152,9 +152,9 @@ static inline bool is_y_data(const struct input_event *evt) {
     return evt->type == INPUT_EV_REL && evt->code == INPUT_REL_Y;
 }
 
-static void apply_config(const struct input_listener_config_entry *cfg,
-                         struct input_listener_processor_data *processor_data,
-                         struct input_listener_data *data, struct input_event *evt) {
+static int apply_config(const struct input_listener_config_entry *cfg,
+                        struct input_listener_processor_data *processor_data,
+                        struct input_listener_data *data, struct input_event *evt) {
     size_t remainder_index = 0;
     for (size_t p = 0; p < cfg->processors_len; p++) {
         const struct zmk_input_processor_entry *proc_e = &cfg->processors[p];
@@ -185,13 +185,23 @@ static void apply_config(const struct input_listener_config_entry *cfg,
 
         struct zmk_input_processor_state state = {.remainder = remainder};
 
-        zmk_input_processor_handle_event(proc_e->dev, evt, proc_e->param1, proc_e->param2, &state);
+        int ret = zmk_input_processor_handle_event(proc_e->dev, evt, proc_e->param1, proc_e->param2,
+                                                   &state);
+        switch (ret) {
+        case ZMK_INPUT_PROC_CONTINUE:
+            continue;
+        default:
+            return ret;
+        }
     }
+
+    return ZMK_INPUT_PROC_CONTINUE;
 }
-static void filter_with_input_config(const struct input_listener_config *cfg,
-                                     struct input_listener_data *data, struct input_event *evt) {
+
+static int filter_with_input_config(const struct input_listener_config *cfg,
+                                    struct input_listener_data *data, struct input_event *evt) {
     if (!evt->dev) {
-        return;
+        return -ENODEV;
     }
 
     for (size_t oi = 0; oi < cfg->layer_overrides_len; oi++) {
@@ -201,9 +211,13 @@ static void filter_with_input_config(const struct input_listener_config *cfg,
         uint8_t layer = 0;
         while (mask != 0) {
             if (mask & BIT(0) && zmk_keymap_layer_active(layer)) {
-                apply_config(&override->config, override_data, data, evt);
+                int ret = apply_config(&override->config, override_data, data, evt);
+
+                if (ret < 0) {
+                    return ret;
+                }
                 if (!override->process_next) {
-                    return;
+                    return 0;
                 }
             }
 
@@ -212,7 +226,7 @@ static void filter_with_input_config(const struct input_listener_config *cfg,
         }
     }
 
-    apply_config(&cfg->base, &data->base_processor_data, data, evt);
+    return apply_config(&cfg->base, &data->base_processor_data, data, evt);
 }
 
 static void clear_xy_data(struct input_listener_xy_data *data) {
@@ -247,8 +261,15 @@ static void apply_resolution_scaling(struct input_listener_data *data, struct in
 
 static void input_handler(const struct input_listener_config *config,
                           struct input_listener_data *data, struct input_event *evt) {
-    // First, filter to update the event data as needed.
-    filter_with_input_config(config, data, evt);
+    // First, process to update the event data as needed.
+    int ret = filter_with_input_config(config, data, evt);
+
+    if (ret < 0) {
+        LOG_ERR("Error applying input processors: %d", ret);
+        return;
+    } else if (ret == ZMK_INPUT_PROC_STOP) {
+        return;
+    }
 
 #if IS_ENABLED(CONFIG_ZMK_POINTING_SMOOTH_SCROLLING)
     apply_resolution_scaling(data, evt);

app/src/pointing/input_processor_code_mapper.c

@@ -25,7 +25,7 @@ static int cm_handle_event(const struct device *dev, struct input_event *event,
     const struct cm_config *cfg = dev->config;
 
     if (event->type != cfg->type) {
-        return 0;
+        return ZMK_INPUT_PROC_CONTINUE;
     }
 
     for (int i = 0; i < cfg->mapping_size / 2; i++) {
@@ -37,7 +37,7 @@ static int cm_handle_event(const struct device *dev, struct input_event *event,
         }
     }
 
-    return 0;
+    return ZMK_INPUT_PROC_CONTINUE;
 }
 
 static struct zmk_input_processor_driver_api cm_driver_api = {

app/src/pointing/input_processor_scaler.c

@@ -47,7 +47,7 @@ static int scaler_handle_event(const struct device *dev, struct input_event *eve
     const struct scaler_config *cfg = dev->config;
 
     if (event->type != cfg->type) {
-        return 0;
+        return ZMK_INPUT_PROC_CONTINUE;
     }
 
     for (int i = 0; i < cfg->codes_len; i++) {
@@ -56,7 +56,7 @@ static int scaler_handle_event(const struct device *dev, struct input_event *eve
         }
     }
 
-    return 0;
+    return ZMK_INPUT_PROC_CONTINUE;
 }
 
 static struct zmk_input_processor_driver_api scaler_driver_api = {

app/src/pointing/input_processor_temp_layer.c

@@ -162,7 +162,7 @@ static int temp_layer_handle_event(const struct device *dev, struct input_event
         k_work_reschedule(&layer_disable_works[param1], K_MSEC(param2));
     }
 
-    return 0;
+    return ZMK_INPUT_PROC_CONTINUE;
 }
 
 static int temp_layer_init(const struct device *dev) {

app/src/pointing/input_processor_transform.c

@@ -42,7 +42,7 @@ static int ipt_handle_event(const struct device *dev, struct input_event *event,
     const struct ipt_config *cfg = dev->config;
 
     if (event->type != cfg->type) {
-        return 0;
+        return ZMK_INPUT_PROC_CONTINUE;
     }
 
     if (param1 & INPUT_TRANSFORM_XY_SWAP) {
@@ -65,7 +65,7 @@ static int ipt_handle_event(const struct device *dev, struct input_event *event,
         event->value = -event->value;
     }
 
-    return 0;
+    return ZMK_INPUT_PROC_CONTINUE;
 }
 
 static struct zmk_input_processor_driver_api ipt_driver_api = {