5 files changed, 51 insertions, 0 deletions
diff --git a/include/config.h b/include/config.h
index a915fbed..5e1c39f3 100644
--- a/include/config.h
+++ b/include/config.h
@@ -135,6 +135,7 @@ struct sway_config {
 	list_t *workspace_outputs;
 	list_t *output_configs;
 	list_t *criteria;
+	list_t *active_bar_modifiers;
 	struct sway_mode *current_mode;
 	struct bar_config *current_bar;
 	uint32_t floating_mod;
@@ -176,6 +177,11 @@ void merge_output_config(struct output_config *dst, struct output_config *src);
 void apply_output_config(struct output_config *oc, swayc_t *output);
 void free_output_config(struct output_config *oc);
 
+/**
+ * Updates the list of active bar modifiers
+ */
+void update_active_bar_modifiers(void);
+
 int workspace_output_cmp_workspace(const void *a, const void *b);
 
 int sway_binding_cmp(const void *a, const void *b);
diff --git a/include/input_state.h b/include/input_state.h
index a1f238e1..79e27d91 100644
--- a/include/input_state.h
+++ b/include/input_state.h
@@ -60,6 +60,12 @@ extern struct pointer_state {
 	int mode;
 } pointer_state;
 
+enum modifier_state {
+	MOD_STATE_UNCHANGED = 0,
+	MOD_STATE_PRESSED = 1,
+	MOD_STATE_RELEASED = 2
+};
+
 void pointer_position_set(struct wlc_origin *new_origin, bool force_focus);
 void center_pointer_on(swayc_t *view);
 
@@ -75,5 +81,19 @@ void pointer_mode_reset(void);
 
 void input_init(void);
 
+/**
+ * Check if state of mod changed from current state to new_state.
+ *
+ * Returns MOD_STATE_UNCHANGED if the state didn't change, MOD_STATE_PRESSED if
+ * the state changed to pressed and MOD_STATE_RELEASED if the state changed to
+ * released.
+ */
+uint32_t modifier_state_changed(uint32_t new_state, uint32_t mod);
+
+/**
+ * Update the current modifiers state to new_state.
+ */
+void modifiers_state_update(uint32_t new_state);
+
 #endif
 
diff --git a/include/ipc-server.h b/include/ipc-server.h
index 04975093..47026bfd 100644
--- a/include/ipc-server.h
+++ b/include/ipc-server.h
@@ -15,6 +15,12 @@ void ipc_event_barconfig_update(struct bar_config *bar);
  * Send IPC mode event to all listening clients
  */
 void ipc_event_mode(const char *mode);
+/**
+ * Sends an IPC modifier event to all listening clients.  The modifier event
+ * includes a key 'change' with the value of state and a key 'modifier' with
+ * the name of that modifier.
+ */
+void ipc_event_modifier(uint32_t modifier, const char *state);
 const char *swayc_type_string(enum swayc_types type);
 
 #endif
diff --git a/include/ipc.h b/include/ipc.h
index e0b3b736..56593529 100644
--- a/include/ipc.h
+++ b/include/ipc.h
@@ -17,6 +17,7 @@ enum ipc_command_type {
 	IPC_EVENT_WINDOW = (1 << 31 | 3),
 	IPC_EVENT_BARCONFIG_UPDATE = (1 << 31 | 4),
 	IPC_EVENT_BINDING = (1 << 31 | 5),
+	IPC_EVENT_MODIFIER = (1 << 31 | 6),
 	IPC_SWAY_GET_PIXELS = 0x81
 };
 
diff --git a/include/util.h b/include/util.h
index 9cb861dd..4bbb64c8 100644
--- a/include/util.h
+++ b/include/util.h
@@ -1,6 +1,10 @@
 #ifndef _SWAY_UTIL_H
 #define _SWAY_UTIL_H
 
+#include <stdint.h>
+#include <wlc/wlc.h>
+#include <xkbcommon/xkbcommon.h>
+
 /**
  * Wrap i into the range [0, max[
  */
@@ -11,4 +15,18 @@ int wrap(int i, int max);
  */
 int numlen(int n);
 
+/**
+ * Get modifier mask from modifier name.
+ *
+ * Returns the modifer mask or 0 if the name isn't found.
+ */
+uint32_t get_modifier_mask_by_name(const char *name);
+
+/**
+ * Get modifier name from modifier mask.
+ *
+ * Returns the modifier name or NULL if it isn't found.
+ */
+const char *get_modifier_name_by_mask(uint32_t modifier);
+
 #endif