info: introduce di_logger

This can be used by parsers (EDID, CTA, DisplayID, etc) to report
errors.

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

edid.c

@@ -1,6 +1,5 @@
 #include <assert.h>
 #include <errno.h>
-#include <stdarg.h>
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
@@ -8,6 +7,7 @@
 #include "bits.h"
 #include "dmt.h"
 #include "edid.h"
+#include "log.h"
 
 /**
  * The size of an EDID block, defined in section 2.2.
@@ -27,31 +27,13 @@
  */
 static const uint8_t header[] = { 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00 };
 
-static void
-va_add_failure(struct di_edid *edid, const char fmt[], va_list args)
-{
-	if (!edid->failure_msg_file) {
-		edid->failure_msg_file = open_memstream(&edid->failure_msg,
-						        &edid->failure_msg_size);
-		if (!edid->failure_msg_file) {
-			return;
-		}
-
-		fprintf(edid->failure_msg_file, "Block 0, Base EDID:\n");
-	}
-
-	fprintf(edid->failure_msg_file, "  ");
-	vfprintf(edid->failure_msg_file, fmt, args);
-	fprintf(edid->failure_msg_file, "\n");
-}
-
 static void
 add_failure(struct di_edid *edid, const char fmt[], ...)
 {
 	va_list args;
 
 	va_start(args, fmt);
-	va_add_failure(edid, fmt, args);
+	_di_logger_va_add_failure(edid->logger, fmt, args);
 	va_end(args);
 }
 
@@ -65,7 +47,7 @@ add_failure_until(struct di_edid *edid, int revision, const char fmt[], ...)
 	}
 
 	va_start(args, fmt);
-	va_add_failure(edid, fmt, args);
+	_di_logger_va_add_failure(edid->logger, fmt, args);
 	va_end(args);
 }
 
@@ -679,9 +661,10 @@ parse_ext(struct di_edid *edid, const uint8_t data[static EDID_BLOCK_SIZE])
 }
 
 struct di_edid *
-_di_edid_parse(const void *data, size_t size)
+_di_edid_parse(const void *data, size_t size, FILE *failure_msg_file)
 {
 	struct di_edid *edid;
+	struct di_logger logger;
 	int version, revision;
 	size_t exts_len, i;
 	const uint8_t *standard_timing_data, *byte_desc_data, *ext_data;
@@ -722,6 +705,12 @@ _di_edid_parse(const void *data, size_t size)
 		return NULL;
 	}
 
+	logger = (struct di_logger) {
+		.f = failure_msg_file,
+		.section = "Block 0, Base EDID",
+	};
+	edid->logger = &logger;
+
 	edid->version = version;
 	edid->revision = revision;
 
@@ -755,16 +744,7 @@ _di_edid_parse(const void *data, size_t size)
 		}
 	}
 
-	if (edid->failure_msg_file) {
-		if (fflush(edid->failure_msg_file) != 0) {
-			_di_edid_destroy(edid);
-			return NULL;
-		}
-
-		fclose(edid->failure_msg_file);
-		edid->failure_msg_file = NULL;
-	}
-
+	edid->logger = NULL;
 	return edid;
 }
 
@@ -774,11 +754,6 @@ _di_edid_destroy(struct di_edid *edid)
 	size_t i;
 	struct di_edid_ext *ext;
 
-	if (edid->failure_msg_file) {
-		fclose(edid->failure_msg_file);
-	}
-	free(edid->failure_msg);
-
 	for (i = 0; i < edid->standard_timings_len; i++) {
 		free(edid->standard_timings[i]);
 	}

include/edid.h

@@ -58,9 +58,7 @@ struct di_edid {
 	struct di_edid_ext *exts[EDID_MAX_BLOCK_COUNT];
 	size_t exts_len;
 
-	char *failure_msg;
-	size_t failure_msg_size;
-	FILE *failure_msg_file;
+	struct di_logger *logger;
 };
 
 struct di_edid_display_descriptor {
@@ -86,7 +84,7 @@ struct di_edid_ext {
  * di_edid_destroy().
  */
 struct di_edid *
-_di_edid_parse(const void *data, size_t size);
+_di_edid_parse(const void *data, size_t size, FILE *failure_msg_file);
 
 /**
  * Destroy an EDID data structure.

include/info.h

@@ -9,6 +9,8 @@
 
 struct di_info {
 	struct di_edid *edid;
+
+	char *failure_msg;
 };
 
 #endif

include/log.h

@@ -0,0 +1,21 @@
+#ifndef LOG_H
+#define LOG_H
+
+/**
+ * Private logging utilities.
+ */
+
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdio.h>
+
+struct di_logger {
+	FILE *f;
+	const char *section;
+	bool initialized;
+};
+
+void
+_di_logger_va_add_failure(struct di_logger *logger, const char fmt[], va_list args);
+
+#endif

info.c

@@ -5,32 +5,57 @@
 
 #include "edid.h"
 #include "info.h"
+#include "log.h"
 
 struct di_info *
 di_info_parse_edid(const void *data, size_t size)
 {
 	struct di_edid *edid;
 	struct di_info *info;
+	char *failure_msg = NULL;
+	size_t failure_msg_size;
+	FILE *failure_msg_file;
 
-	edid = _di_edid_parse(data, size);
-	if (!edid)
+	failure_msg_file = open_memstream(&failure_msg,
+					  &failure_msg_size);
+	if (!failure_msg_file)
 		return NULL;
 
+	edid = _di_edid_parse(data, size, failure_msg_file);
+	if (!edid)
+		goto err_failure_msg_file;
+
 	info = calloc(1, sizeof(*info));
-	if (!info) {
-		_di_edid_destroy(edid);
-		return NULL;
-	}
+	if (!info)
+		goto err_edid;
 
 	info->edid = edid;
 
+	if (fflush(failure_msg_file) != 0)
+		goto err_info;
+	fclose(failure_msg_file);
+	if (failure_msg && failure_msg[0] != '\0')
+		info->failure_msg = failure_msg;
+	else
+		free(failure_msg);
+
 	return info;
+
+err_info:
+	free(info);
+err_edid:
+	_di_edid_destroy(edid);
+err_failure_msg_file:
+	fclose(failure_msg_file);
+	free(failure_msg);
+	return NULL;
 }
 
 void
 di_info_destroy(struct di_info *info)
 {
 	_di_edid_destroy(info->edid);
+	free(info->failure_msg);
 	free(info);
 }
 
@@ -43,7 +68,7 @@ di_info_get_edid(const struct di_info *info)
 const char *
 di_info_get_failure_msg(const struct di_info *info)
 {
-	return info->edid->failure_msg;
+	return info->failure_msg;
 }
 
 char *

log.c

@@ -0,0 +1,17 @@
+#include "log.h"
+
+void
+_di_logger_va_add_failure(struct di_logger *logger, const char fmt[], va_list args)
+{
+	if (!logger->initialized) {
+		if (ftell(logger->f) > 0) {
+			fprintf(logger->f, "\n");
+		}
+		fprintf(logger->f, "%s:\n", logger->section);
+		logger->initialized = true;
+	}
+
+	fprintf(logger->f, "  ");
+	vfprintf(logger->f, fmt, args);
+	fprintf(logger->f, "\n");
+}

meson.build

@@ -39,6 +39,7 @@ di_lib = library(
 		'dmt-table.c',
 		'edid.c',
 		'info.c',
+		'log.c',
 	],
 	include_directories: include_directories('include'),
 	link_args: symbols_flag,