Logging rewrite

src/kernel/logging/klog.c

@@ -1,14 +1,97 @@
 #include "klog.h"
 
 #include <stdarg.h>
+#include <stdbigos/stdio.h>
 #include <stdbigos/types.h>
 
-// NOTE: In the future this lib should manage logging (formating and outputing to the screen or uart) on its own.
-//  Right now I will leave it as is, will change once the basic kernel at least runs.
 #include "debug/debug_stdio.h"
 
 static u32 g_indent_level = 0;
 static const char* g_prefixes[] = {"[ERROR]", "[WARNING]", "[ ]", "[~]"};
+static const char* g_overflow_warning = "[WARNING]Some of the logs were lost due to overflow";
+
+#ifdef __DEBUG__
+	#define RING_BUF_SIZE (1 << 20)
+#else
+	#define RING_BUF_SIZE (1 << 16)
+#endif // !__DEBUG__
+
+#define TEMP_BUF_SIZE (1 << 12)
+
+typedef struct {
+	char ring[RING_BUF_SIZE];
+	i32 read;
+	i32 write;
+	bool full;
+	bool overflown;
+	void (*uart_tx)(char c);
+} ring_buffer_t;
+
+static ring_buffer_t g_buffer;
+
+static ring_buffer_t* get_buffer() {
+	return &g_buffer;
+}
+
+static void put_char(ring_buffer_t* rb, const char c) {
+	if (c == '\0')
+		return; // Null characters are not suppossed to be logged.
+	rb->ring[rb->write++] = c;
+	rb->write %= RING_BUF_SIZE;
+	if (rb->full) {
+		rb->read = (rb->read + 1) % RING_BUF_SIZE;
+		rb->overflown = true;
+	}
+	rb->full = rb->read == rb->write;
+	if (rb->uart_tx)
+		rb->uart_tx(c);
+}
+
+static void put_string(ring_buffer_t* rb, const char* str) {
+	size_t it = 0;
+	while (str[it]) put_char(rb, str[it++]);
+}
+
+static void put_overflow_warning(ring_buffer_t* rb) {
+	size_t it = 0;
+	i32 temp_write = rb->write;
+	while (g_overflow_warning[it]) {
+		rb->ring[temp_write++] = g_overflow_warning[it++];
+		temp_write %= RING_BUF_SIZE;
+	}
+}
+
+static void put_msg(ring_buffer_t* rb, const char* msg) {
+	put_string(rb, msg);
+	if (rb->overflown)
+		put_overflow_warning(rb);
+}
+
+char ring_buffer_get_char() {
+	ring_buffer_t* rb = get_buffer();
+	if (rb->read == rb->write && !rb->full)
+		return 0;
+	const char ret = rb->ring[rb->read++];
+	rb->read %= RING_BUF_SIZE;
+	rb->full = false;
+	rb->overflown = false;
+	return ret;
+}
+
+void ring_buffer_flush_to_uart() {
+	ring_buffer_t* rb = get_buffer();
+	if (!rb->uart_tx)
+		return;
+	char c;
+	while ((c = ring_buffer_get_char())) rb->uart_tx(c);
+}
+
+void ring_buffer_set_uart_tx_function(void (*uart_tx)(char c), bool flush) {
+	ring_buffer_t* rb = get_buffer();
+	rb->uart_tx = uart_tx;
+	if (flush)
+		ring_buffer_flush_to_uart();
+}
 
 void klog_indent_increase() {
 	++g_indent_level;
@@ -20,22 +103,45 @@ void klog_indent_decrease() {
 }
 
 static void klogv(klog_severity_level_t loglvl, const char* fmt, va_list va) {
-	(void)fmt;
-	(void)va;
+	char temp_buffer[TEMP_BUF_SIZE];
 
 	if (loglvl > KLSL_TRACE) {
 		KLOGLN_ERROR("Invalid loglvl passed to klog");
 		loglvl = KLSL_ERROR;
 	}
 
-	DEBUG_PUTGAP(g_indent_level);
-	DEBUG_PRINTF("%s ", g_prefixes[loglvl]);
-	DEBUG_VPRINTF(fmt, va);
+	size_t written = 0;
+	for (u32 i = 0; i < g_indent_level && written < TEMP_BUF_SIZE - 1; i++) temp_buffer[written++] = ' ';
+
+	const char* prefix = g_prefixes[loglvl];
+	for (size_t i = 0; prefix[i] && written < TEMP_BUF_SIZE - 1; i++) temp_buffer[written++] = prefix[i];
+
+	va_list copy;
+	va_copy(copy, va);
+	int n = vsnprintf(temp_buffer + written, TEMP_BUF_SIZE - written, fmt, copy);
+	va_end(copy);
+
+	// stbsp_vsnprintf doesn't return errors, so just check for truncation
+	if (n < 0)
+		n = 0;
+	written += (size_t)n;
+
+	if (written >= TEMP_BUF_SIZE)
+		written = TEMP_BUF_SIZE - 1;
+	temp_buffer[written] = '\0';
+
+	ring_buffer_t* rb = get_buffer();
+	put_msg(rb, temp_buffer);
+
+	// DEBUG_PUTGAP(g_indent_level);
+	// DEBUG_PRINTF("%s ", g_prefixes[loglvl]);
+	// DEBUG_VPRINTF(fmt, va);
 }
 
 static void kloglnv(klog_severity_level_t loglvl, const char* fmt, va_list va) {
 	klogv(loglvl, fmt, va);
-	DEBUG_PUTC('\n');
+	put_msg(&g_buffer, "\n");
+	// DEBUG_PUTC('\n');
 }
 
 void klog(klog_severity_level_t loglvl, const char* fmt, ...) {

src/kernel/logging/klog.h

@@ -10,6 +10,9 @@ typedef enum {
 	KLSL_TRACE = 3,
 } klog_severity_level_t;
 
+char ring_buffer_get_char();
+void ring_buffer_flush_to_uart();
+void ring_buffer_set_uart_tx_function(void (*uart_tx)(char c), bool flush);
 void klog_indent_increase();
 void klog_indent_decrease();