NeoTachyon/tachyon/files/usr/lib/core/common.uc

#!/usr/bin/env ucode

let fs = require("fs");

global.double = function(v) {
    if (v == null || v == "")
        return 0.0;
    return v * 1.0;
};

function as_string(value) {
    return value == null ? "" : "" + value;
}

function read_json_file(path) {
    let data = fs.readfile(path);
    if (data == null)
        return null;

    try {
        return json(data);
    }
    catch (e) {
        return null;
    }
}

function read_stdin() {
    let input = fs.open("/dev/stdin", "r");
    if (!input)
        return "";
    let data = input.read("all");
    input.close();
    return data == null ? "" : data;
}

function read_stdin_json() {
    let data = read_stdin();
    try {
        return json(data);
    }
    catch (e) {
        return null;
    }
}

function write_json(value) {
    print(sprintf("%J", value), "\n");
}

function write_compact_string_array(values) {
    print("[");
    for (let i = 0; i < length(values); i++) {
        if (i > 0)
            print(",");
        print(sprintf("%J", as_string(values[i])));
    }
    print("]\n");
}

function csv_to_json_array(value) {
    value = as_string(value);
    write_compact_string_array(value == "" ? [] : split(value, ","));
}

function write_json_file(path, value) {
    path = as_string(path);
    let stamp = clock();
    let tmp_path = sprintf("%s.%d.%d.tmp", path, stamp[0], stamp[1]);
    let result = fs.writefile(tmp_path, sprintf("%J\n", value));
    if (result == null || (type(result) == "boolean" && !result)) {
        try { fs.unlink(tmp_path); } catch(e) {}
        return false;
    }
    if (!fs.rename(tmp_path, path)) {
        try { fs.unlink(tmp_path); } catch(e) {}
        return false;
    }
    return true;
}

function strip_internal_fields(value) {
    if (type(value) == "array") {
        for (let i = 0; i < length(value); i++)
            value[i] = strip_internal_fields(value[i]);
        return value;
    }

    if (type(value) == "object") {
        for (let key in keys(value)) {
            if (substr(key, 0, 2) == "__") {
                delete value[key];
                continue;
            }
            value[key] = strip_internal_fields(value[key]);
        }
    }

    return value;
}

function array_or_empty(value) {
    return type(value) == "array" ? value : [];
}

function object_or_empty(value) {
    return type(value) == "object" ? value : {};
}

function object_key_count(value) {
    return type(value) == "object" ? length(keys(value)) : 0;
}

function option(section, key, fallback) {
    if (fallback == null)
        fallback = "";
    let value = object_or_empty(section)[key];
    if (value == null)
        return fallback;
    if (type(value) == "array")
        return join(" ", value);
    return as_string(value);
}

function list_option(section, key) {
    let value = object_or_empty(section)[key];
    if (value == null)
        return [];
    if (type(value) == "array")
        return value;
    let text = trim(as_string(value));
    return text == "" ? [] : split(text, /[ \t\r\n]+/);
}

function bool_option(section, key, fallback) {
    if (fallback == null)
        fallback = false;
    let value = option(section, key, fallback ? "1" : "0");
    return value == "1" || value == "true" || value == "yes" || value == "on";
}

function int_option(section, key, fallback) {
    let value = option(section, key, fallback);
    if (match(value, /[^0-9]/))
        return int(fallback, 10);
    return int(value, 10);
}

function shell_quote(value) {
    return "'" + replace(as_string(value), /'/g, "'\\''") + "'";
}

function command_from_args(args) {
    let parts = [];
    for (let arg in args)
        push(parts, shell_quote(arg));
    return join(" ", parts);
}

function command_status(command) {
    let status = int(system(command));
    if (status == -1)
        return 255;
    let signal = status & 127;
    if (signal != 0)
        return 128 + signal;
    return (status >> 8) & 255;
}

function command_success(command) {
    return command_status("(" + command + ") >/dev/null 2>&1") == 0;
}

function command_success_from_args(args) {
    return command_success(command_from_args(args));
}

function command_capture(command) {
    let p = fs.popen(command, "r");
    if (!p) return null;
    let output = as_string(p.read("all") || "");
    let status = p.close();
    if (status == -1)
        status = 255;
    else {
        let signal = status & 127;
        if (signal != 0)
            status = 128 + signal;
        else
            status = (status >> 8) & 255;
    }
    return { status: status, output: output };
}

function command_output(command) {
    let res = command_capture(command);
    return res ? res.output : "";
}

function command_output_from_args(args) {
    return command_output(command_from_args(args) + " 2>/dev/null");
}

return {
    as_string,
    read_json_file,
    read_stdin,
    read_stdin_json,
    write_json,
    write_compact_string_array,
    csv_to_json_array,
    write_json_file,
    strip_internal_fields,
    array_or_empty,
    object_or_empty,
    object_key_count,
    option,
    list_option,
    bool_option,
    int_option,
    shell_quote,
    command_from_args,
    command_status,
    command_success,
    command_success_from_args,
    command_capture,
    command_output,
    command_output_from_args
};