Add simple logging system

include/neatvnc.h

@@ -19,9 +19,35 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <limits.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <assert.h>
 
 #define NVNC_NO_PTS UINT64_MAX
 
+#define nvnc_log(lvl, fmt, ...) do { \
+	assert(lvl != NVNC_LOG_TRACE); \
+	struct nvnc_log_data ld = { \
+		.level = lvl, \
+		.file = __FILE__, \
+		.line = __LINE__, \
+	}; \
+	nvnc__log(&ld, fmt, ## __VA_ARGS__); \
+} while(0)
+
+#ifndef NDEBUG
+#define nvnc_trace(fmt, ...) do { \
+	struct nvnc_log_data ld = { \
+		.level = NVNC_LOG_TRACE, \
+		.file = __FILE__, \
+		.line = __LINE__, \
+	}; \
+	nvnc__log(&ld, fmt, ## __VA_ARGS__); \
+} while(0)
+#else
+#define nvnc_trace(...)
+#endif
+
 struct nvnc;
 struct nvnc_client;
 struct nvnc_display;
@@ -56,6 +82,21 @@ enum nvnc_transform {
 	NVNC_TRANSFORM_FLIPPED_270 = 7,
 };
 
+enum nvnc_log_level {
+	NVNC_LOG_PANIC = 0,
+	NVNC_LOG_ERROR = 1,
+	NVNC_LOG_WARNING = 2,
+	NVNC_LOG_INFO = 3,
+	NVNC_LOG_DEBUG = 4,
+	NVNC_LOG_TRACE = 5,
+};
+
+struct nvnc_log_data {
+	enum nvnc_log_level level;
+	const char* file;
+	int line;
+};
+
 typedef void (*nvnc_key_fn)(struct nvnc_client*, uint32_t key,
                             bool is_pressed);
 typedef void (*nvnc_pointer_fn)(struct nvnc_client*, uint16_t x, uint16_t y,
@@ -70,6 +111,7 @@ typedef bool (*nvnc_auth_fn)(const char* username, const char* password,
 typedef void (*nvnc_cut_text_fn)(struct nvnc*, const char* text, uint32_t len);
 typedef void (*nvnc_fb_release_fn)(struct nvnc_fb*, void* context);
 typedef void (*nvnc_cleanup_fn)(void* userdata);
+typedef void (*nvnc_log_fn)(const struct nvnc_log_data*, const char* message);
 
 extern const char nvnc_version[];
 
@@ -151,3 +193,7 @@ void nvnc_send_cut_text(struct nvnc*, const char* text, uint32_t len);
 void nvnc_set_cursor(struct nvnc*, struct nvnc_fb*, uint16_t width,
 		     uint16_t height, uint16_t hotspot_x, uint16_t hotspot_y,
 		     bool is_damaged);
+
+void nvnc_set_log_fn(nvnc_log_fn);
+void nvnc_set_log_level(enum nvnc_log_level);
+void nvnc__log(const struct nvnc_log_data*, const char* fmt, ...);

meson.build

@@ -84,6 +84,7 @@ sources = [
 	'src/murmurhash.c',
 	'src/encoder.c',
 	'src/cursor.c',
+	'src/logging.c',
 ]
 
 dependencies = [

src/logging.c

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2019 - 2022 Andri Yngvason
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+ * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+ * AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+ * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+ * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+ * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+ * PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "neatvnc.h"
+#include "common.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+
+#define EXPORT __attribute__((visibility("default")))
+
+static void default_logger(const struct nvnc_log_data* meta,
+		const char* message);
+
+static nvnc_log_fn log_fn = default_logger;
+
+#ifndef NDEBUG
+static enum nvnc_log_level log_level = NVNC_LOG_DEBUG;
+#else
+static enum nvnc_log_level log_level = NVNC_LOG_WARNING;
+#endif
+
+static const char* log_level_to_string(enum nvnc_log_level level)
+{
+	switch (level) {
+	case NVNC_LOG_PANIC: return "PANIC";
+	case NVNC_LOG_ERROR: return "ERROR";
+	case NVNC_LOG_WARNING: return "Warning";
+	case NVNC_LOG_INFO: return "Info";
+	case NVNC_LOG_DEBUG: return "DEBUG";
+	case NVNC_LOG_TRACE: return "TRACE";
+	}
+
+	return "UNKNOWN";
+}
+
+static FILE* stream_for_log_level(enum nvnc_log_level level)
+{
+	switch (level) {
+	case NVNC_LOG_PANIC: return stderr;
+	case NVNC_LOG_ERROR: return stderr;
+	case NVNC_LOG_WARNING: return stderr;
+	case NVNC_LOG_INFO: return stdout;
+	case NVNC_LOG_DEBUG: return stdout;
+	case NVNC_LOG_TRACE: return stdout;
+	}
+
+	return stderr;
+}
+
+static void nvnc__vlog(const struct nvnc_log_data* meta, const char* fmt,
+		va_list args)
+{
+	char message[1024];
+
+	if (meta->level <= log_level) {
+		vsnprintf(message, sizeof(message), fmt, args);
+		log_fn(meta, message);
+	}
+
+	if (meta->level == NVNC_LOG_PANIC)
+		abort();
+}
+
+static void default_logger(const struct nvnc_log_data* meta,
+		const char* message)
+{
+	const char* level = log_level_to_string(meta->level);
+	FILE* stream = stream_for_log_level(meta->level);
+
+	if (meta->level == NVNC_LOG_INFO)
+		fprintf(stream, "Info: %s\n", message);
+	else
+		fprintf(stream, "%s: %s: %d: %s\n", level, meta->file,
+				meta->line, message);
+
+	fflush(stream);
+}
+
+EXPORT
+void nvnc_set_log_level(enum nvnc_log_level level)
+{
+	log_level = level;
+}
+
+EXPORT
+void nvnc_set_log_fn(nvnc_log_fn fn)
+{
+	log_fn = fn;
+}
+
+EXPORT
+void nvnc__log(const struct nvnc_log_data* meta,
+		const char* fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	nvnc__vlog(meta, fmt, ap);
+	va_end(ap);
+}