Expose API for retrieving event names

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

.gitignore

@@ -46,3 +46,4 @@ ylwrap
 *.tar.*
 *.3
 libevdev-events
+event-names.h

libevdev/Makefile.am

@@ -9,3 +9,11 @@ libevdev_la_LDFLAGS = -version-info $(LIBEVDEV_LT_VERSION) -export-symbols-regex
 
 libevdevincludedir = $(includedir)/libevdev-1.0/libevdev
 libevdevinclude_HEADERS = libevdev.h
+
+event-names.h: Makefile make-event-names.py
+	        $(srcdir)/make-event-names.py --output=c > $@
+
+EXTRA_DIST = make-event-names.py
+CLEANFILES = event-names.h
+BUILT_SOURCES = event-names.h
+

libevdev/libevdev.c

@@ -29,6 +29,7 @@
 
 #include "libevdev.h"
 #include "libevdev-int.h"
+#include "event-names.h"
 
 #define MAXEVENTS 64
 
@@ -937,3 +938,33 @@ libevdev_grab(struct libevdev *dev, int grab)
 
 	return rc < 0 ? -errno : 0;
 }
+
+const char*
+libevdev_get_event_type_name(unsigned int type)
+{
+	if (type > EV_MAX)
+		return NULL;
+
+	return ev_map[type];
+}
+
+const char*
+libevdev_get_event_code_name(unsigned int type, unsigned int code)
+{
+	if (type > EV_MAX)
+		return NULL;
+
+	if (code > ev_max[type])
+		return NULL;
+
+	return event_type_map[type][code];
+}
+
+const char*
+libevdev_get_input_prop_name(unsigned int prop)
+{
+	if (prop > INPUT_PROP_MAX)
+		return NULL;
+
+	return input_prop_map[prop];
+}

libevdev/libevdev.h

@@ -464,4 +464,32 @@ int libevdev_disable_event_code(struct libevdev *dev, unsigned int type, unsigne
  */
 int libevdev_kernel_set_abs_value(struct libevdev *dev, unsigned int code, const struct input_absinfo *abs);
 
+/**
+ * @return The name of the given event type (e.g. EV_ABS) or NULL for an
+ * invalid type
+ *
+ * @note The list of names is compiled into libevdev. If the kernel adds new
+ * defines for new properties libevdev will not automatically pick these up.
+ */
+const char * libevdev_get_event_type_name(unsigned int type);
+/**
+ * @return The name of the given event code (e.g. ABS_X) or NULL for an
+ * invalid type or code
+ *
+ * @note The list of names is compiled into libevdev. If the kernel adds new
+ * defines for new properties libevdev will not automatically pick these up.
+ */
+const char * libevdev_get_event_code_name(unsigned int type, unsigned int code);
+
+/**
+ * @return The name of the given input prop (e.g. INPUT_PROP_BUTTONPAD) or NULL for an
+ * invalid property
+ *
+ * @note The list of names is compiled into libevdev. If the kernel adds new
+ * defines for new properties libevdev will not automatically pick these up.
+ * @note On older kernels input properties may not be defined and
+ * libevdev_get_input_prop_name will always return NULL
+ */
+const char * libevdev_get_input_prop_name(unsigned int prop);
+
 #endif /* libevdev_H */

libevdev/make-event-names.py

@@ -0,0 +1,178 @@
+#!/usr/bin/env python
+# Parses linux/input.h scanning for #define KEY_FOO 134
+# Prints a C header file or a Python file that can be used as
+# mapping table
+#
+
+import re
+import sys
+import argparse
+
+SOURCE_FILE = "/usr/include/linux/input.h"
+
+class Bits(object):
+	pass
+
+prefixes = [
+		"EV_",
+		"REL_",
+		"ABS_",
+		"KEY_",
+		"BTN_",
+		"LED_",
+		"SND_",
+		"MSC_",
+		"SW_",
+		"FF_",
+		"SYN_",
+		"INPUT_PROP_",
+]
+
+blacklist = [
+		"EV_VERSION"
+]
+
+def print_bits(bits, prefix):
+	if  not hasattr(bits, prefix):
+		return
+	print "static const char * const %s_map[%s_MAX + 1] = {" % (prefix, prefix.upper())
+	print "	[0 ... %s_MAX] = NULL," % prefix.upper()
+	for val, name in getattr(bits, prefix).items():
+		print "	[%s] = \"%s\"," % (name, name)
+	print "};"
+	print ""
+
+def print_python_bits(bits, prefix):
+	if  not hasattr(bits, prefix):
+		return
+
+	print "%s_map = {" % (prefix)
+	for val, name in getattr(bits, prefix).items():
+		print "	%d : \"%s\"," % (val, name)
+	print "}"
+	print "for k, v in %s_map.items():" % (prefix)
+	print "	%s_map[v] = k" % (prefix)
+	print ""
+
+def print_map(bits):
+	print "static const char * const * const event_type_map[EV_MAX + 1] = {"
+	print "	[0 ... EV_MAX] = NULL,"
+
+	for prefix in prefixes:
+		if prefix == "BTN_" or prefix == "EV_" or prefix == "INPUT_PROP_":
+			continue
+		print "	[EV_%s] = %s_map," % (prefix[:-1], prefix[:-1].lower())
+
+	print "};"
+	print ""
+
+	print "static const int ev_max[EV_MAX + 1] = {"
+	for prefix in prefixes:
+		if prefix == "BTN_" or prefix == "EV_" or prefix == "INPUT_PROP_":
+			continue
+		print "	[EV_%s] = %s_MAX," % (prefix[:-1], prefix[:-1])
+	print "};"
+	print ""
+
+def print_python_map(bits):
+	print "map = {"
+
+	for val, name in getattr(bits, "ev").items():
+		name = name[3:]
+		if name == "REP" or name == "PWR"  or name == "FF_STATUS"  or name == "MAX":
+			continue
+		print "	%d : %s_map," % (val, name.lower())
+
+	print "}"
+	print ""
+
+def print_mapping_table(bits):
+	print "/* THIS FILE IS GENERATED, DO NOT EDIT */"
+	print ""
+	print "#ifndef EVENT_NAMES_H"
+	print "#define EVENT_NAMES_H"
+	print ""
+	print "#define SYN_MAX 3 /* linux/input.h doesn't define that */"
+	print ""
+
+	for prefix in prefixes:
+		if prefix == "BTN_":
+			continue
+		print_bits(bits, prefix[:-1].lower())
+
+	print_map(bits)
+
+	print "#endif /* EVENT_NAMES_H */"
+
+def print_python_mapping_table(bits):
+	print "# THIS FILE IS GENERATED, DO NOT EDIT"
+	print ""
+
+	for prefix in prefixes:
+		if prefix == "BTN_":
+			continue
+		print_python_bits(bits, prefix[:-1].lower())
+
+	print_python_map(bits)
+
+	print "def event_get_type_name(type):"
+	print "	return ev_map[type]"
+	print ""
+	print ""
+	print "def event_get_code_name(type, code):"
+	print "	if map.has_key(type) and map[type].has_key(code):"
+	print "		return map[type][code]"
+	print "	return 'UNKNOWN'"
+	print ""
+
+def parse_define(bits, line):
+	m = re.match(r"^#define\s+(\w+)\s+(\w+)", line)
+	if m == None:
+		return
+
+	name = m.group(1)
+
+	if name in blacklist:
+		return
+
+	try:
+		value = int(m.group(2), 0)
+	except ValueError:
+		return
+
+	for prefix in prefixes:
+		if not name.startswith(prefix):
+			continue
+
+		attrname = prefix[:-1].lower()
+		if attrname == "btn":
+			attrname = "key"
+
+		if not hasattr(bits, attrname):
+			setattr(bits, attrname, {})
+		b = getattr(bits, attrname)
+		b[value] = name
+
+def parse(path):
+	fp = open(path)
+
+	bits = Bits()
+
+	lines = fp.readlines()
+	for line in lines:
+		if not line.startswith("#define"):
+			continue
+		parse_define(bits, line)
+
+	return bits
+
+if __name__ == "__main__":
+	bits = parse(SOURCE_FILE)
+	parser = argparse.ArgumentParser()
+	parser.add_argument("--output", default="c")
+
+	args = parser.parse_args(sys.argv[1:])
+	if args.output == "python":
+		print_python_mapping_table(bits)
+	else:
+		print_mapping_table(bits)

man/Makefile.am

@@ -7,6 +7,7 @@ dist_man3_MANS = $(shell find . -name "libevdev_*.3" -printf "%P\n")
 man_src = \
 	libevdev_enable_event_type.txt	\
 	libevdev_get_abs_min.txt	\
+	libevdev_get_event_type_name.txt\
 	libevdev_get_name.txt		\
 	libevdev_get_num_slots.txt	\
 	libevdev_get_phys.txt		\

man/libevdev_get_event_type_name.txt

@@ -0,0 +1,71 @@
+libevdev_get_event_type_name(3)
+===============================
+
+NAME
+----
+
+libevdev_get_event_type_name, libevdev_get_event_code_name, libevdev_get_input_prop_name - get the name of the event type, code or input property
+
+SYNOPSIS
+--------
+
+#include <libevdev/libevdev.h>
+
+const char * libevdev_get_event_type_name(unsigned int type);
+
+const char * libevdev_get_event_code_name(unsigned int type, unsigned int code);
+
+const char * libevdev_get_input_prop_name(unsigned int prop);
+
+DESCRIPTION
+-----------
+*libevdev_get_event_type_name*, *libevdev_get_event_code_name* and
+*libevdev_get_input_prop_name* are helper functions for callers that need to
+display the symbolic name of an event type or code or an input property.
+
+*libevdev_get_event_type_name* returns the name of the event type as string.
+Possible return values include EV_SYN, EV_REL, EV_ABS, EV_LED, etc.
+
+*libevdev_get_event_code_name* returns the name of the event code as string.
+Possible return values include ABS_X, ABS_Y, REL_X, BTN_TOOL_DOUBLETAP, etc.
+
+*libevdev_get_input_prop_name* returns the name of the input property as
+string. Possible return values include INPUT_PROP_BUTTONPAD,
+INPUT_PROP_POINTER, etc.
+
+PARAMETERS
+----------
+*type*::
+	Specifies the event type to query. The valid range for 'type' is 0 to
+	EV_MAX.
+
+*code*::
+	Specifies the event code to query. The valid range for 'code'
+	depends on the 'type' and is defined in <linux/input.h>. For
+	example, for 'type' EV_ABS, the range is 0 to 'ABS_MAX'.
+
+*prop*::
+	Specifies the input property to query. The valid range for 'prop' is
+	0 to INPUT_PROP_MAX.
+
+
+RETURN VALUE
+------------
+On success, *libevdev_get_event_type_name* and *libevdev_get_event_code_name* return
+the symbolic name of the event type or code. If no such name is defined or
+'type' or 'code' are outside of the valid range, NULL is returned.
+
+
+On success, *libevdev_get_input_prop_name* returns the symbolic name of the
+input property. If no such name is defined or 'prop' is outside
+of the valid range, NULL is returned.
+
+NOTES
+-----
+Use with caution.
+The set of event names is built into libevdev and does not change even if
+the underlying kernel changes the set of symbolic names. It is the set of
+event names as defined on the host libevdev was built on. A rebuild of
+libevdev is required to sync the event names with linux/input.h.
+This affects both event names and ranges.
+