Add keymap wrappers for introspection into the keymap. (#17229)

* Introspection handlers for keymaps.

* Renaming.

builddefs/build_keyboard.mk

@@ -390,10 +390,12 @@ ifneq ("$(KEYMAP_H)","")
     CONFIG_H += $(KEYMAP_H)
 endif
 
+OPT_DEFS += -DKEYMAP_C=\"$(KEYMAP_C)\"
+
 # project specific files
 SRC += \
     $(KEYBOARD_SRC) \
-    $(KEYMAP_C) \
+    $(QUANTUM_DIR)/keymap_introspection.c \
     $(QUANTUM_SRC) \
     $(QUANTUM_DIR)/main.c \
 

quantum/keymap.h

@@ -55,3 +55,5 @@ extern const uint16_t keymaps[][MATRIX_ROWS][MATRIX_COLS];
 // Ensure we have a forward declaration for the encoder map
 #    include "encoder.h"
 #endif
+
+#include "keymap_introspection.h"

quantum/keymap_introspection.c

@@ -0,0 +1,25 @@
+// Copyright 2022 Nick Brassel (@tzarc)
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+// Pull the actual keymap code so that we can inspect stuff from it
+#include KEYMAP_C
+
+#include "keymap_introspection.h"
+
+#define NUM_KEYMAP_LAYERS ((uint8_t)(sizeof(keymaps) / ((MATRIX_ROWS) * (MATRIX_COLS) * sizeof(uint16_t))))
+
+uint8_t keymap_layer_count(void) {
+    return NUM_KEYMAP_LAYERS;
+}
+
+#if defined(ENCODER_ENABLE) && defined(ENCODER_MAP_ENABLE)
+
+#    define NUM_ENCODERMAP_LAYERS ((uint8_t)(sizeof(encoder_map) / ((NUM_ENCODERS) * (2) * sizeof(uint16_t))))
+
+uint8_t encodermap_layer_count(void) {
+    return NUM_ENCODERMAP_LAYERS;
+}
+
+_Static_assert(NUM_KEYMAP_LAYERS == NUM_ENCODERMAP_LAYERS, "Number of encoder_map layers doesn't match the number of keymap layers");
+
+#endif // defined(ENCODER_ENABLE) && defined(ENCODER_MAP_ENABLE)

quantum/keymap_introspection.h

@@ -0,0 +1,15 @@
+// Copyright 2022 Nick Brassel (@tzarc)
+// SPDX-License-Identifier: GPL-2.0-or-later
+#pragma once
+
+#include <stdint.h>
+
+// Get the number of layers defined in the keymap
+uint8_t keymap_layer_count(void);
+
+#if defined(ENCODER_ENABLE) && defined(ENCODER_MAP_ENABLE)
+
+// Get the number of layers defined in the encoder map
+uint8_t encodermap_layer_count(void);
+
+#endif // defined(ENCODER_ENABLE) && defined(ENCODER_MAP_ENABLE)