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- implement json escape for a log message while in json log mode
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- defer logging until log json mode is set
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@igorshevach
igorshevach committed Jan 4, 2024
1 parent 8a4227d commit b08cd98
Showing 1 changed file with 121 additions and 103 deletions.
224 changes: 121 additions & 103 deletions transcoder/utils/logger.c
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Original file line number Diff line number Diff line change
Expand Up @@ -53,109 +53,9 @@ pthread_mutex_t logger_locker;
char context_id[256] = {0};
char channel_id[256] = {0};

#define FWRITE_STR(x) fwrite(x,1,sizeof(x)-1,out)

/*
https://tc39.es/ecma262/multipage/structured-data.html#sec-json.stringify
*/
static size_t json_escape(FILE *out, const char *str)
{
const char *start = str;
while (*str)
{
char chr = *str;

if (chr == '"' || chr == '\\' || chr == '/')
{
FWRITE_STR("\\");
putc(chr,out);
}
else if (chr == '\b')
{
FWRITE_STR("\\b");
}
else if (chr == '\f')
{
FWRITE_STR("\\f");
}
else if (chr == '\n')
{
FWRITE_STR("\\n");
}
else if (chr == '\r')
{
FWRITE_STR("\\r");
}
else if (chr == '\t')
{
FWRITE_STR("\\t");
}
else if (!isprint(chr))
{
FWRITE_STR("\\u");
for (int i = 0; i < 4; i++)
{
int value = (chr >> 12) & 0xf;
if (value >= 0 && value <= 9)
putc((char)('0' + value),out);
else if (value >= 10 && value <= 15)
putc((char)('A' + (value - 10)),out);
chr <<= 4;
}
}
else
{
putc(chr,out);
}
str++;
}
return str - start;
}

typedef struct {
char *buf;
size_t size;
FILE *fp;
} mem_stream_t;

static mem_stream_t aux_mem_stream = {.buf = NULL,.size = 0,.fp = NULL};
static int stringify_message(FILE *out, const char *fmt, va_list args);

static int open_mem_stream(mem_stream_t *stream) {
if(!stream->fp){
stream->fp = open_memstream(&stream->buf,&stream->size);
}
if(!stream->fp) {
fprintf(stderr,"ERROR: could not open_memstream - os error code %d", errno);
return -1;
}
return 0;
}

static int JSONStringifyMessage(FILE *out, const char *fmt, va_list args) {
int ret = -1;
FWRITE_STR("\"");
if (args!=NULL) {
if((ret = open_mem_stream(&aux_mem_stream))){
goto error;
}
if((ret = fseek(aux_mem_stream.fp, 0, SEEK_SET))) {
fprintf(stderr,"ERROR: could not fseek %d - os error code %d", ret, errno);
goto error;
}
if( (ret = vfprintf(aux_mem_stream.fp, fmt, args )) > 0){
fflush(aux_mem_stream.fp);
aux_mem_stream.buf[ret] = '\0';
ret = json_escape(out, aux_mem_stream.buf);
} else {
fprintf(stderr,"WARNING: vfprintf error %d. os error code %d", ret, errno);
}
} else {
ret = json_escape(out, fmt);
}
error:
FWRITE_STR("\"");
return ret;
}
void logger_unit_test();

void logger2(const char* category,const char* subcategory,int level,const char *fmt, bool newLine, va_list args)
{
Expand All @@ -177,7 +77,7 @@ void logger2(const char* category,const char* subcategory,int level,const char *
fprintf( out, "{\"time\": \"%s.%03ld\", \"channelId\": \"%s\", \"category\": \"%s:%s\", \"logLevel\": \"%s\","
"\"contextId\": \"%s\", \"pthread\":\"%lx\", \"log\": ",buf,( (now % 1000000)/1000 ), channel_id, category,
subcategory!=NULL ? subcategory : "", levelStr,context_id,pthread_self());
JSONStringifyMessage(out, fmt, args);
stringify_message(out, fmt, args);
fprintf( out, "}\n" );
} else {
fprintf( out, "%s.%03ld %s:%s %s |%s| [%lx] ",buf,( (now % 1000000)/1000 ),category,subcategory!=NULL ? subcategory : "", levelStr,context_id,pthread_self());
Expand Down Expand Up @@ -284,3 +184,121 @@ void loggerFlush()
fflush(stderr);
fflush(stdout);
}

/*
json logger utils
*/

#define FWRITE_STR(x) fwrite(x,1,sizeof(x)-1,out)

/*
escapes string according to https://tc39.es/ecma262/multipage/structured-data.html#sec-json.stringify
*/
const char *hex = "0123456789ABCDEF";
static size_t json_escape(FILE *out, const char *str) {
const char *start = str;
while (*str) {
char chr = *str;

if (chr == '"' || chr == '\\' || chr == '/') {
FWRITE_STR("\\");
putc(chr,out);
} else if (chr == '\b') {
FWRITE_STR("\\b");
} else if (chr == '\f') {
FWRITE_STR("\\f");
} else if (chr == '\n') {
FWRITE_STR("\\n");
} else if (chr == '\r') {
FWRITE_STR("\\r");
} else if (chr == '\t') {
FWRITE_STR("\\t");
} else if (!isprint(chr)) {
FWRITE_STR("\\u");
for (int i = 0; i < 4; i++) {
int value = (chr >> 12) & 0xf;
if (value >= 0 && value <= 15)
putc(hex[value],out);
chr <<= 4;
}
} else {
putc(chr,out);
}
str++;
}
return str - start;
}

typedef struct {
char *buf;
size_t size;
FILE *fp;
} mem_stream_t;

static mem_stream_t aux_mem_stream = {.buf = NULL,.size = 0,.fp = NULL};

static int open_mem_stream(mem_stream_t *stream) {
if(!stream->fp){
stream->fp = open_memstream(&stream->buf,&stream->size);
}
if(!stream->fp) {
fprintf(stderr,"ERROR: could not open_memstream - os error code %d", errno);
return -1;
}
return 0;
}

/*
stringify_message. prints log message as a json stringified string
NOTE: not thread safe! must be called from within a lock.
*/
static int stringify_message(FILE *out, const char *fmt, va_list args) {
int ret = -1;
FWRITE_STR("\"");
if (args!=NULL) {
if((ret = open_mem_stream(&aux_mem_stream))){
goto error;
}
if((ret = fseek(aux_mem_stream.fp, 0, SEEK_SET))) {
fprintf(stderr,"ERROR: could not fseek %d - os error code %d", ret, errno);
goto error;
}
if( (ret = vfprintf(aux_mem_stream.fp, fmt, args )) > 0){
fflush(aux_mem_stream.fp);
aux_mem_stream.buf[ret] = '\0';
ret = json_escape(out, aux_mem_stream.buf);
} else {
fprintf(stderr,"WARNING: vfprintf error %d. os error code %d", ret, errno);
}
} else {
ret = json_escape(out, fmt);
}
error:
FWRITE_STR("\"");
return ret;
}

/*
runtime test
*/
void logger_unit_test() {
const char *special = "\a\b\t\n\r\f\"\\";
char table [255+sizeof(special)-1],
*walker = table;
memcpy(walker,special,strlen(special));
walker += strlen(special);
for(int i = 1; i < 256; i++) {
*walker++ = (char)i;
}

srand((unsigned) time(NULL));
for (int i = 0; i < 1024; i++) {
int a = rand() % sizeof(table), b = rand() % sizeof(table);
int temp = table[a];
table[a] = table[b];
table[b] = temp;

LOGGER(CATEGORY_DEFAULT,AV_LOG_WARNING,"%s", table);
}
exit(0);
}

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