ardupilot/libraries/AP_Scripting/lua_bindings.cpp

#include <AP_Common/AP_Common.h>
#include <SRV_Channel/SRV_Channel.h>
#include <AP_HAL/HAL.h>
#include <AP_Logger/AP_Logger.h>

#include "lua_bindings.h"

#include "lua_boxed_numerics.h"
#include <AP_Scripting/lua_generated_bindings.h>

extern const AP_HAL::HAL& hal;

int check_arguments(lua_State *L, int expected_arguments, const char *fn_name);
int check_arguments(lua_State *L, int expected_arguments, const char *fn_name) {
#if defined(AP_SCRIPTING_CHECKS) && AP_SCRIPTING_CHECKS >= 1
    if (expected_arguments < 0) {
       AP_HAL::panic("Lua: Attempted to check for negative arguments");
    }
#endif

    const int args = lua_gettop(L);
    if (args != expected_arguments) {
        return luaL_error(L, "%s expected %d arguments got %d", fn_name, expected_arguments, args);
    }
    return 0;
}

// millis
static int lua_millis(lua_State *L) {
    check_arguments(L, 0, "millis");

    new_uint32_t(L);
    *check_uint32_t(L, -1) = AP_HAL::millis();

    return 1;
}

static const luaL_Reg global_functions[] =
{
    {"millis", lua_millis},
    {NULL, NULL}
};

static int AP_Logger_Write(lua_State *L) {
    AP_Logger * AP_logger = AP_Logger::get_singleton();
    if (AP_logger == nullptr) {
        return luaL_argerror(L, 1, "logger not supported on this firmware");
    }

    // check we have at least 4 arguments passed in
    const int args = lua_gettop(L);
    if (args < 4) {
        return luaL_argerror(L, args, "too few arguments");
    }

    const char * name = luaL_checkstring(L, 1);
    const char * labels = luaL_checkstring(L, 2);
    const char * fmt = luaL_checkstring(L, 3);

    // cheack the name, labels and format are not too long
    if (strlen(name) >= LS_NAME_SIZE) {
        return luaL_error(L, "Name must be 4 or less chars long");
    }
    int length = strlen(labels);
    if (length >= (LS_LABELS_SIZE - 7)) { // need 7 chars to add 'TimeUS,'
        return luaL_error(L, "labels must be less than 58 chars long");
    }
    // Count the number of commas
    uint8_t commas = 1;
    for (uint8_t i=0; i<length; i++) {
        if (labels[i] == ',') {
            commas++;
        }
    }
    // check the number of arguments matches the number of values in the label
    if (args - 3 != commas) {
        return luaL_argerror(L, args, "label does not match No. of arguments");
    }

    length = strlen(fmt);
    if (length >= (LS_FORMAT_SIZE - 1)) { // need 1 char to add timestamp
        return luaL_error(L, "format must be less than 15 chars long");
    }

    // check the number of arguments matches the length of the foramt string
    if (args - 3 != length) {
        return luaL_argerror(L, args, "format does not match No. of arguments");
    }

    // prepend timestamp to format and labels
    char label_cat[LS_LABELS_SIZE];
    strcpy(label_cat,"TimeUS,");
    strcat(label_cat,labels);
    char fmt_cat[LS_FORMAT_SIZE];
    strcpy(fmt_cat,"Q");
    strcat(fmt_cat,fmt);

    // ask for a mesage type
    struct AP_Logger::log_write_fmt *f = AP_logger->msg_fmt_for_name(name, label_cat, nullptr, nullptr, fmt_cat, true);
    if (f == nullptr) {
        // unable to map name to a messagetype; could be out of
        // msgtypes, could be out of slots, ...
        return luaL_argerror(L, args, "could not map message type");
    }

    // work out how long the block will be
    int16_t msg_len = AP_logger->Write_calc_msg_len(fmt_cat);
    if (msg_len == -1) {
        return luaL_argerror(L, args, "unknown format");
    }

    luaL_Buffer buffer;
    luaL_buffinit(L, &buffer);

    // add logging headers
    const char header[2] = {(char)HEAD_BYTE1, (char)HEAD_BYTE2};
    luaL_addlstring(&buffer, header, sizeof(header));
    luaL_addlstring(&buffer, (char *)&f->msg_type, sizeof(f->msg_type));

    // timestamp is always first value
    const uint64_t now = AP_HAL::micros64();
    luaL_addlstring(&buffer, (char *)&now, sizeof(uint64_t));

    for (uint8_t i=4; i<=args; i++) {
        uint8_t charlen = 0;
        switch(fmt_cat[i-3]) {
            // logger varable types not available to scripting
            // 'b': int8_t
            // 'h': int16_t
            // 'c': int16_t
            // 'd': double
            // 'H': uint16_t
            // 'C': uint16_t
            // 'Q': uint64_t
            // 'q': int64_t
            // 'a': arrays
            case 'i':
            case 'L':
            case 'e': {
                const lua_Integer tmp1 = luaL_checkinteger(L, i);
                luaL_argcheck(L, ((tmp1 >= INT32_MIN) && (tmp1 <= INT32_MAX)), i, "argument out of range");
                int32_t tmp = tmp1;
                luaL_addlstring(&buffer, (char *)&tmp, sizeof(int32_t));
                break;
            }
            case 'f': {
                float tmp = luaL_checknumber(L, i);
                luaL_argcheck(L, ((tmp >= -INFINITY) && (tmp <= INFINITY)), i, "argument out of range");
                luaL_addlstring(&buffer, (char *)&tmp, sizeof(float));
                break;
            }
            case 'n': {
                charlen = 4;
                break;
            }
            case 'M':
            case 'B': {
                const lua_Integer tmp1 = luaL_checkinteger(L, i);
                luaL_argcheck(L, ((tmp1 >= 0) && (tmp1 <= UINT8_MAX)), i, "argument out of range");
                uint8_t tmp = static_cast<uint8_t>(tmp1);
                luaL_addlstring(&buffer, (char *)&tmp, sizeof(uint8_t));
                break;
            }
            case 'I':
            case 'E': {
                const uint32_t tmp = coerce_to_uint32_t(L, i);
                luaL_addlstring(&buffer, (char *)&tmp, sizeof(uint32_t));
                break;
            }
            case 'N': {
                charlen = 16;
                break;
            }
            case 'Z': {
                charlen = 64;
                break;
            }
            default: {
                return luaL_error(L, "%c unsupported format",fmt_cat[i-3]);
            }
        }
        if (charlen != 0) {
            const char *tmp = luaL_checkstring(L, i);
            if (strlen(tmp) > charlen) {
                return luaL_error(L, "arg %i too long for %c format",i,fmt_cat[i-3]);
            }
            luaL_addlstring(&buffer, (char *)&tmp, charlen);
        }
    }

    AP_logger->Safe_Write_Emit_FMT(f);

    luaL_pushresult(&buffer);
    AP_logger->WriteBlock(buffer.b,msg_len);

    return 0;
}

const luaL_Reg AP_Logger_functions[] = {
    {"write", AP_Logger_Write},
    {NULL, NULL}
};

void load_lua_bindings(lua_State *L) {
    lua_pushstring(L, "logger");
    luaL_newlib(L, AP_Logger_functions);
    lua_settable(L, -3);

    luaL_setfuncs(L, global_functions, 0);
}