Add a CLI tool

For now it only prints the JSON representation of the information
exposed by libdisplay-info.

A JSON schema [1] and libjsonschema [2] are used to encode JSON.

[1]: https://json-schema.org/
[2]: https://sr.ht/~emersion/libjsonschema/

Signed-off-by: Simon Ser <contact@emersion.fr>

meson.build

@@ -85,4 +85,5 @@ di_dep = declare_dependency(
 meson.override_dependency('libdisplay-info', di_dep)
 
 subdir('di-edid-decode')
+subdir('tool')
 subdir('test')

tool/main.c

@@ -0,0 +1,129 @@
+#include <getopt.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <libdisplay-info/edid.h>
+#include <libdisplay-info/info.h>
+
+#include "schema.h"
+
+static struct edid *
+get_edid(const struct di_edid *edid)
+{
+	const struct di_edid_vendor_product *vendor_product;
+	char manufacturer[4];
+	struct edid *wire_edid;
+	struct edid_vendor_product *wire_vendor_product;
+
+	vendor_product = di_edid_get_vendor_product(edid);
+
+	snprintf(manufacturer, sizeof(manufacturer), "%.3s", vendor_product->manufacturer);
+
+	wire_vendor_product = malloc(sizeof(*wire_vendor_product));
+	*wire_vendor_product = (struct edid_vendor_product) {
+		.manufacturer = strdup(manufacturer),
+		.product = vendor_product->product,
+		.serial = vendor_product->serial,
+		.model_year = vendor_product->model_year,
+		.manufacture_week = vendor_product->manufacture_week,
+		.manufacture_year = vendor_product->manufacture_year,
+	};
+
+	wire_edid = malloc(sizeof(*wire_edid));
+	*wire_edid = (struct edid) {
+		.version = di_edid_get_version(edid),
+		.revision = di_edid_get_revision(edid),
+		.vendor_product = wire_vendor_product,
+	};
+
+	return wire_edid;
+}
+
+static struct display_info *
+get_info(const struct di_info *info)
+{
+	const struct di_edid *edid;
+	struct edid *wire_edid = NULL;
+	struct display_info *wire_info;
+
+	edid = di_info_get_edid(info);
+	if (edid != NULL)
+		wire_edid = get_edid(edid);
+
+	wire_info = malloc(sizeof(*wire_info));
+	*wire_info = (struct display_info) {
+		.edid = wire_edid,
+	};
+
+	return wire_info;
+}
+
+static const char usage[] =
+	"usage: libdisplay-info <edid>\n";
+
+static const struct option long_options[] = {
+	{ "help", no_argument, 0, 'h' },
+	{ 0, 0, 0, 0 }
+};
+
+int
+main(int argc, char *argv[])
+{
+	FILE *in;
+	static uint8_t raw[32 * 1024];
+	size_t size = 0;
+	struct di_info *info;
+	int opt;
+	struct jsch_encoder *enc;
+	struct display_info *wire_info;
+
+	in = stdin;
+	while (1) {
+		int option_index = 0;
+		opt = getopt_long(argc, argv, "h", long_options, &option_index);
+		if (opt == -1)
+			break;
+
+		fprintf(stderr, "%s", usage);
+		return opt == 'h' ? 0 : 1;
+	}
+
+	if (argc > 1) {
+		in = fopen(argv[1], "r");
+		if (!in) {
+			perror("failed to open input file");
+			return 1;
+		}
+	}
+
+	while (!feof(in)) {
+		size += fread(&raw[size], 1, sizeof(raw) - size, in);
+		if (ferror(in)) {
+			perror("fread failed");
+			return 1;
+		} else if (size >= sizeof(raw)) {
+			fprintf(stderr, "input too large\n");
+			return 1;
+		}
+	}
+
+	fclose(in);
+
+	info = di_info_parse_edid(raw, size);
+	if (!info) {
+		perror("di_edid_parse failed");
+		return 1;
+	}
+
+	wire_info = get_info(info);
+
+	enc = jsch_encoder_create(stdout);
+	display_info_encode(wire_info, enc);
+	jsch_encoder_destroy(enc);
+	printf("\n");
+
+	display_info_finish(wire_info);
+	free(wire_info);
+	di_info_destroy(info);
+	return 0;
+}

tool/meson.build

@@ -0,0 +1,40 @@
+libjsonschema = dependency('libjsonschema')
+libjsonschema_native = dependency('libjsonschema', native: true)
+libjsonschema_tool_path = libjsonschema_native.get_variable(pkgconfig: 'tool', internal: 'tool')
+libjsonschema_tool = find_program(libjsonschema_tool_path, native: true)
+
+schema = files('schema.json')
+
+schema_header = custom_target(
+	'schema.h',
+	command: [libjsonschema_tool, 'gen-header', '@INPUT@'],
+	input: schema,
+	output: 'schema.h',
+	capture: true,
+)
+
+schema_code = custom_target(
+	'schema.c',
+	command: [libjsonschema_tool, 'gen-code', '@INPUT@'],
+	input: schema,
+	output: 'schema.c',
+	capture: true,
+)
+
+schema_lib = static_library(
+	'schema',
+	schema_code,
+	c_args: cc.get_supported_arguments(['-Wno-declaration-after-statement']),
+	dependencies: libjsonschema,
+)
+
+executable(
+	'libdisplay-info',
+	[
+		'main.c',
+		schema_header,
+	],
+	dependencies: [di_dep, libjsonschema],
+	link_with: schema_lib,
+	install: true,
+)

tool/schema.json

@@ -0,0 +1,53 @@
+{
+	"$schema": "https://json-schema.org/draft/2020-12/schema",
+	"$ref": "#/$defs/edid",
+	"$defs": {
+		"uint16": {
+			"type": "integer",
+			"minimum": 0,
+			"maximum": 65535
+		},
+		"uint32": {
+			"type": "integer",
+			"minimum": 0,
+			"maximum": 4294967295
+		},
+		"display_info": {
+			"type": "object",
+			"additionalProperties": false,
+			"properties": {
+				"edid": { "$ref": "#/$defs/edid" }
+			}
+		},
+		"edid": {
+			"type": "object",
+			"additionalProperties": false,
+			"properties": {
+				"version": { "type": "integer" },
+				"revision": { "type": "integer" },
+				"vendor_product": { "$ref": "#/$defs/edid_vendor_product" }
+			},
+			"required": [
+				"version",
+				"revision",
+				"vendor_product"
+			]
+		},
+		"edid_vendor_product": {
+			"type": "object",
+			"additionalProperties": false,
+			"properties": {
+				"manufacturer": { "type": "string" },
+				"product": { "$ref": "#/$defs/uint16" },
+				"serial": { "$ref": "#/$defs/uint32" },
+				"model_year": { "type": "integer" },
+				"manufacture_week": { "type": "integer" },
+				"manufacture_year": { "type": "integer" }
+			},
+			"required": [
+				"manufacturer",
+				"product"
+			]
+		}
+	}
+}