uterm: input: add string_to_keysym() helper

This new helper can be used to convert a string description of a keysym
into a real keysym. This is required to allow users to configure keyboard
shortcuts and more.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

src/uterm.h

@@ -332,6 +332,8 @@ bool uterm_input_is_awake(struct uterm_input *input);
 
 void uterm_input_keysym_to_string(struct uterm_input *input,
 				  uint32_t keysym, char *str, size_t size);
+int uterm_input_string_to_keysym(struct uterm_input *input, const char *n,
+				 uint32_t *out);
 
 /*
  * System Monitor

src/uterm_input.c

@@ -488,3 +488,19 @@ void uterm_input_keysym_to_string(struct uterm_input *input,
 
 	kbd_desc_keysym_to_string(input->desc, keysym, str, size);
 }
+
+int uterm_input_string_to_keysym(struct uterm_input *input, const char *n,
+				 uint32_t *out)
+{
+	if (!n || !out)
+		return -EINVAL;
+
+	if (input)
+		return kbd_desc_string_to_keysym(input->desc, n, out);
+
+#ifdef UTERM_HAVE_XKBCOMMON
+	return uxkb_string_to_keysym(n, out);
+#endif
+
+	return plain_string_to_keysym(n, out);
+}

src/uterm_input_plain.c

@@ -430,12 +430,20 @@ static void plain_keysym_to_string(uint32_t keysym, char *str, size_t size)
 	snprintf(str, size, "%#x", keysym);
 }
 
+int plain_string_to_keysym(const char *n, uint32_t *out)
+{
+	/* TODO: we really need to implement this; maybe use a hashtable similar
+	 * to the Xlib? */
+	return -EOPNOTSUPP;
+}
+
 const struct kbd_desc_ops plain_desc_ops = {
 	.init = plain_desc_init,
 	.ref = plain_desc_ref,
 	.unref = plain_desc_unref,
 	.alloc = plain_desc_alloc,
 	.keysym_to_string = plain_keysym_to_string,
+	.string_to_keysym = plain_string_to_keysym,
 };
 
 const struct kbd_dev_ops plain_dev_ops = {

src/uterm_input_uxkb.c

@@ -292,12 +292,27 @@ static void uxkb_keysym_to_string(uint32_t keysym, char *str, size_t size)
 	xkb_keysym_get_name(keysym, str, size);
 }
 
+int uxkb_string_to_keysym(const char *n, uint32_t *out)
+{
+	uint32_t keysym;
+
+	/* TODO: fix xkbcommon upstream to be case-insensitive if case-sensitive
+	 * match fails. */
+	sym = xkb_keysym_from_name(n);
+	if (!sym)
+		return -EFAULT;
+
+	*out = sym;
+	return 0;
+}
+
 const struct kbd_desc_ops uxkb_desc_ops = {
 	.init = uxkb_desc_init,
 	.ref = uxkb_desc_ref,
 	.unref = uxkb_desc_unref,
 	.alloc = uxkb_desc_alloc,
 	.keysym_to_string = uxkb_keysym_to_string,
+	.string_to_keysym = uxkb_string_to_keysym,
 };
 
 const struct kbd_dev_ops uxkb_dev_ops = {

src/uterm_internal.h

@@ -418,6 +418,7 @@ struct kbd_desc_ops {
 	void (*unref) (struct kbd_desc *desc);
 	int (*alloc) (struct kbd_desc *desc, struct kbd_dev **out);
 	void (*keysym_to_string) (uint32_t keysym, char *str, size_t size);
+	int (*string_to_keysym) (const char *n, uint32_t *out);
 };
 
 struct kbd_dev_ops {
@@ -440,6 +441,8 @@ static const bool plain_available = true;
 extern const struct kbd_desc_ops plain_desc_ops;
 extern const struct kbd_dev_ops plain_dev_ops;
 
+extern int plain_string_to_keysym(const char *n, uint32_t *out);
+
 #ifdef UTERM_HAVE_XKBCOMMON
 
 struct uxkb_desc {
@@ -455,6 +458,8 @@ static const bool uxkb_available = true;
 extern const struct kbd_desc_ops uxkb_desc_ops;
 extern const struct kbd_dev_ops uxkb_dev_ops;
 
+extern int uxkb_string_to_keysym(const char *n, uint32_t *out);
+
 #else /* !UTERM_HAVE_XKBCOMMON */
 
 struct uxkb_desc {
@@ -560,6 +565,16 @@ static inline void kbd_desc_keysym_to_string(struct kbd_desc *desc,
 	return desc->ops->keysym_to_string(keysym, str, size);
 }
 
+static inline int kbd_desc_string_to_keysym(struct kbd_desc *desc,
+					    const char *n,
+					    uint32_t *out)
+{
+	if (!desc)
+		return -EINVAL;
+
+	return desc->ops->string_to_keysym(n, out);
+}
+
 static inline void kbd_dev_ref(struct kbd_dev *dev)
 {
 	if (!dev)