path: root/src/lua/log.c

#include <assert.h>
#include <string.h>

#include "log.h"

static lua_CFunction lua_log_getinfo = NULL;

static lua_CFunction lua_log_stringformat = NULL;

static lua_CFunction lua_log_tostring = NULL;

static void lua_log_debuginfo(lua_State *state, const char **module, const char **func,
                              char buffer[], size_t size)
{
    lua_pushcfunction(state, lua_log_getinfo);

    // Ignore the first frame (the c function itself)
    lua_pushnumber(state, 2);

    // S: source, l: currentline, n: name
    const char *query = "Sln";
    lua_pushstring(state, query);

    if (lua_pcall(state, 2, 1, 0) == LUA_OK) {
        lua_getfield(state, -1, "short_src");
        const char *shortsrc = lua_tostring(state, -1);

        lua_getfield(state, -2, "currentline");
        int line = lua_tointeger(state, -1);

        lua_getfield(state, -3, "name");
        const char *name = lua_tostring(state, -1);

        if (!strncmp(shortsrc, "[string ", 8)) {
            int length = strlen(shortsrc);
            snprintf(buffer, size, "%.*s", length - 9, shortsrc + 8);

            *func = buffer;
            *module = "lua";
        } else {
            snprintf(buffer, size, "%s:%d", shortsrc, line);

            *func = name ? name : "?";
            *module = buffer;
        }
    } else {
        log_trace("Failed to retrieve Lua debug information");
    }

    lua_pop(state, 3);
}

// Normal logging with any_log_format
//
static int lua_log_wrapper(lua_State *state, int skip_args, any_log_level_t level)
{
    // Use string.format to print safely
    //
    int n_args = lua_gettop(state);
    lua_pushcfunction(state, lua_log_stringformat);

    for (int i = 1; i <= n_args; ++i)
        lua_pushvalue(state, skip_args + i);

    lua_call(state, n_args, 1);
    const char *message = lua_tostring(state, -1);

    const char *module, *func;
    char buffer[4096];
    lua_log_debuginfo(state, &module, &func, buffer, sizeof(buffer));

    any_log_format(level, module, func, "%s", message);
    return 0;
}

static int lua_log_format(lua_State *state)
{
    const char *param = luaL_checkstring(state, 1);
    any_log_level_t level = any_log_level_from_string(param);

    if (level == ANY_LOG_ALL)
        luaL_error(state, "Invalid log level, got \"%s\"", param);

    return lua_log_wrapper(state, 1, level);
}

static int lua_log_error(lua_State *state)
{
    return lua_log_wrapper(state, 0, ANY_LOG_ERROR);
}

static int lua_log_warn(lua_State *state)
{
    return lua_log_wrapper(state, 0, ANY_LOG_WARN);
}

static int lua_log_info(lua_State *state)
{
    return lua_log_wrapper(state, 0, ANY_LOG_INFO);
}

static int lua_log_debug(lua_State *state)
{
    return lua_log_wrapper(state, 0, ANY_LOG_DEBUG);
}

static int lua_log_trace(lua_State *state)
{
    return lua_log_wrapper(state, 0, ANY_LOG_TRACE);
}

// Structured logging with any_log_value
//
static int lua_log_wrapperv(lua_State *state, any_log_level_t level)
{
    const char *message = lua_tostring(state, 1);
    lua_remove(state, 1);
    luaL_checktype(state, 1, LUA_TTABLE);

    const char *module, *func;
    char buffer[4096];
    lua_log_debuginfo(state, &module, &func, buffer, sizeof(buffer));

    any_log_value(level, module, func, message,
                  "g:value", ANY_LOG_FORMATTER(lua_print_value), state,
                  NULL);
    return 0;
}

static int lua_log_formatv(lua_State *state)
{
    const char *param = luaL_checkstring(state, 1);
    any_log_level_t level = any_log_level_from_string(param);

    if (level == ANY_LOG_ALL)
        luaL_error(state, "Invalid log level, got \"%s\"", param);

    lua_remove(state, 1);
    return lua_log_wrapperv(state, level);
}

static int lua_log_errorv(lua_State *state)
{
    return lua_log_wrapperv(state, ANY_LOG_ERROR);
}

static int lua_log_warnv(lua_State *state)
{
    return lua_log_wrapperv(state, ANY_LOG_WARN);
}

static int lua_log_infov(lua_State *state)
{
    return lua_log_wrapperv(state, ANY_LOG_INFO);
}

static int lua_log_debugv(lua_State *state)
{
    return lua_log_wrapperv(state, ANY_LOG_DEBUG);
}

static int lua_log_tracev(lua_State *state)
{
    return lua_log_wrapperv(state, ANY_LOG_TRACE);
}

void lua_print_value(FILE *stream, lua_State *state)
{
    lua_print_value_at(stream, state, 1);
}

void lua_print_value_at(FILE *stream, lua_State *state, int index)
{
    switch (lua_type(state, index)) {
        case LUA_TNIL:
            fprintf(stream, "nil");
            break;

        case LUA_TNUMBER:
            fprintf(stream, "%lf", lua_tonumber(state, index));
            break;

        case LUA_TBOOLEAN:
            fprintf(stream, lua_toboolean(state, index) ? "true" : "false");
            break;

        case LUA_TSTRING:
            fprintf(stream, "\"%s\"", lua_tostring(state, index));
            break;

        case LUA_TTABLE:
            fputc('{', stream);

            bool first = true;
            lua_pushnil(state);
            while (lua_next(state, index) != 0) {
                if (!first) {
                    fputc(',', stream);
                    fputc(' ', stream);
                }
                first = false;

                if (lua_isnumber(state, -2)) {
                    fprintf(stream, "[%ld] = ", lua_tointeger(state, -2));
                } else {
                    fprintf(stream, "%s = ", lua_tostring(state, -2));
                }

                lua_print_value_at(stream, state, lua_gettop(state));
                lua_pop(state, 1);
            }

            fputc('}', stream);
            break;


        case LUA_TFUNCTION:
            fprintf(stream, "function (%p)", lua_topointer(state, index));
            break;

        case LUA_TTHREAD:
            fprintf(stream, "thread (%p)", lua_tothread(state, index));
            break;

        default:
            lua_pushcfunction(state, lua_log_tostring);
            lua_pushvalue(state, index);
            lua_call(state, 1, 1);
            fprintf(stream, "%s", lua_tostring(state, -1));
            lua_pop(state, 1);
            break;
    }
}

int lua_log_library(lua_State *state)
{
    static const luaL_Reg library[] = {
        // TODO: Is it wise to allow panic from Lua?
        //{ "panic",  lua_log_panic },

        { "format", lua_log_format },
        { "error",  lua_log_error },
        { "warn",   lua_log_warn },
        { "info",   lua_log_info },
        { "debug",  lua_log_debug },
        { "trace",  lua_log_trace },

        { "value_format", lua_log_formatv },
        { "value_error",  lua_log_errorv },
        { "value_warn",   lua_log_warnv },
        { "value_info",   lua_log_infov },
        { "value_debug",  lua_log_debugv },
        { "value_trace",  lua_log_tracev },
        { NULL, NULL },
    };

    lua_getglobal(state, "debug");
    lua_getfield(state, -1, "getinfo");
    lua_log_getinfo = lua_tocfunction(state, -1);

    lua_getglobal(state, "string");
    lua_getfield(state, -1, "format");
    lua_log_stringformat = lua_tocfunction(state, -1);

    lua_getglobal(state, "tostring");
    lua_log_tostring = lua_tocfunction(state, -1);

    lua_pop(state, 5);
    luaL_newlib(state, library);
    return 1;
}