int encode_fields(lua_sandbox* lsb, output_data* d, char id, const char* name,
int index)
{
int result = 0;
lua_getfield(lsb->lua, index, name);
if (!lua_istable(lsb->lua, -1)) {
return result;
}
size_t len_pos, len;
lua_checkstack(lsb->lua, 2);
lua_pushnil(lsb->lua);
while (result == 0 && lua_next(lsb->lua, -2) != 0) {
if (pb_write_tag(d, id, 2)) return 1;
len_pos = d->pos;
if (pb_write_varint(d, 0)) return 1; // length tbd later
if (lua_isstring(lsb->lua, -2)) {
const char* s = lua_tolstring(lsb->lua, -2, &len);
if (pb_write_string(d, 1, s, len)) return 1;
} else {
snprintf(lsb->error_message, LSB_ERROR_SIZE,
"field name must be a string");
return 1;
}
if (encode_field_value(lsb, d, 1, NULL)) return 1;
if (update_field_length(d, len_pos)) return 1;
lua_pop(lsb->lua, 1); // Remove the value leaving the key on top for
// the next interation.
}
lua_pop(lsb->lua, 1); // remove the fields table
return result;
}
int encode_int(lua_sandbox* lsb, output_data* d, char id, const char* name)
{
int result = 0;
lua_getfield(lsb->m_lua, 1, name);
if (lua_isnumber(lsb->m_lua, -1)) {
long long i = (long long)lua_tonumber(lsb->m_lua, -1);
if (!(result = pb_write_tag(d, id, 0))) {
result = pb_write_varint(d, i);
}
}
lua_pop(lsb->m_lua, 1);
return result;
}
int pb_write_string(output_data* d, char id, const char* s, size_t len)
{
if (pb_write_tag(d, id, 2)) return 1;
if (pb_write_varint(d, len)) return 1;
size_t needed = len;
if (needed > d->m_size - d->m_pos) {
if (realloc_output(d, needed)) return 1;
}
memcpy(&d->m_data[d->m_pos], s, len);
d->m_pos += len;
return 0;
}
int serialize_table_as_pb(lua_sandbox* lsb, int index)
{
output_data* d = &lsb->output;
d->pos = 0;
size_t needed = 18;
if (needed > d->size) {
if (realloc_output(d, needed)) return 1;
}
// create a type 4 uuid
d->data[d->pos++] = 2 | (1 << 3);
d->data[d->pos++] = 16;
for (int x = 0; x < 16; ++x) {
d->data[d->pos++] = rand() % 255;
}
d->data[8] = (d->data[8] & 0x0F) | 0x40;
d->data[10] = (d->data[10] & 0x0F) | 0xA0;
// use existing or create a timestamp
lua_getfield(lsb->lua, index, "Timestamp");
long long ts;
if (lua_isnumber(lsb->lua, -1)) {
ts = (long long)lua_tonumber(lsb->lua, -1);
} else {
ts = (long long)(time(NULL) * 1e9);
}
lua_pop(lsb->lua, 1);
if (pb_write_tag(d, 2, 0)) return 1;
if (pb_write_varint(d, ts)) return 1;
if (encode_string(lsb, d, 3, "Type", index)) return 1;
if (encode_string(lsb, d, 4, "Logger", index)) return 1;
if (encode_int(lsb, d, 5, "Severity", index)) return 1;
if (encode_string(lsb, d, 6, "Payload", index)) return 1;
if (encode_string(lsb, d, 7, "EnvVersion", index)) return 1;
if (encode_int(lsb, d, 8, "Pid", index)) return 1;
if (encode_string(lsb, d, 9, "Hostname", index)) return 1;
if (encode_fields(lsb, d, 10, "Fields", index)) return 1;
// if we go above 15 pb_write_tag will need to start varint encoding
needed = 1;
if (needed > d->size - d->pos) {
if (realloc_output(d, needed)) return 1;
}
d->data[d->pos] = 0; // NULL terminate incase someone tries to treat this
// as a string
return 0;
}
int update_field_length(output_data* d, size_t len_pos)
{
size_t len = d->pos - len_pos - 1;
if (len < 128) {
d->data[len_pos] = (char)len;
return 0;
}
size_t l = len, cnt = 0;
while (l) {
l >>= 7;
++cnt; // compute the number of bytes needed for the varint length
}
size_t needed = cnt - 1;
if (needed > d->size - d->pos) {
if (realloc_output(d, needed)) return 1;
}
size_t end_pos = d->pos + needed;
memmove(&d->data[len_pos + cnt], &d->data[len_pos + 1], len);
d->pos = len_pos;
if (pb_write_varint(d, len)) return 1;
d->pos = end_pos;
return 0;
}
int encode_field_value(lua_sandbox* lsb, output_data* d, int first,
const char* representation)
{
int result = 1;
size_t len;
const char* s;
int t = lua_type(lsb->lua, -1);
switch (t) {
case LUA_TSTRING:
if (first && representation) { // this uglyness keeps the protobuf
// fields in order without additional
// lookups
if (pb_write_string(d, 3, representation, strlen(representation))) {
return 1;
}
}
s = lua_tolstring(lsb->lua, -1, &len);
result = pb_write_string(d, 4, s, len);
break;
case LUA_TNUMBER:
if (first) {
if (pb_write_tag(d, 2, 0)) return 1;
if (pb_write_varint(d, 3)) return 1;
if (representation) {
if (pb_write_string(d, 3, representation,
strlen(representation))) {
return 1;
}
}
}
result = encode_double(lsb, d, 7);
break;
case LUA_TBOOLEAN:
if (first) {
if (pb_write_tag(d, 2, 0)) return 1;
if (pb_write_varint(d, 4)) return 1;
if (representation) {
if (pb_write_string(d, 3, representation,
strlen(representation))) {
return 1;
}
}
}
if (pb_write_tag(d, 8, 0)) return 1;
result = pb_write_bool(d, lua_toboolean(lsb->lua, -1));
break;
case LUA_TTABLE:
{
lua_rawgeti(lsb->lua, -1, 1);
int t = lua_type(lsb->lua, -1);
lua_pop(lsb->lua, 1); // remove the array test value
if (LUA_TNIL == t) {
result = encode_field_object(lsb, d);
} else {
result = encode_field_array(lsb, d, t, representation);
}
}
break;
default:
snprintf(lsb->error_message, LSB_ERROR_SIZE, "unsupported type %d", t);
result = 1;
}
return result;
}
