v2rayN/v2rayN/ServiceLib/Common/Extension.cs

using System.Diagnostics.CodeAnalysis;

namespace ServiceLib.Common;

public static class Extension
{
    public static bool IsNullOrEmpty([NotNullWhen(false)] this string? value)
    {
        return string.IsNullOrWhiteSpace(value) || string.IsNullOrEmpty(value);
    }

    public static bool IsNotEmpty([NotNullWhen(false)] this string? value)
    {
        return !string.IsNullOrWhiteSpace(value);
    }

    public static string? NullIfEmpty(this string? value)
    {
        return string.IsNullOrWhiteSpace(value) ? null : value;
    }

    public static bool BeginWithAny(this string s, IEnumerable<char> chars)
    {
        if (s.IsNullOrEmpty())
        {
            return false;
        }
        return chars.Contains(s.First());
    }

    private static bool IsWhiteSpace(this string value)
    {
        return value.All(char.IsWhiteSpace);
    }

    public static IEnumerable<string> NonWhiteSpaceLines(this TextReader reader)
    {
        while (reader.ReadLine() is { } line)
        {
            if (line.IsWhiteSpace())
            {
                continue;
            }
            yield return line;
        }
    }

    public static string TrimEx(this string? value)
    {
        return value?.Trim() ?? string.Empty;
    }

    public static string RemovePrefix(this string value, char prefix)
    {
        return value.StartsWith(prefix) ? value[1..] : value;
    }

    public static string RemovePrefix(this string value, string prefix)
    {
        return value.StartsWith(prefix) ? value[prefix.Length..] : value;
    }

    public static string UpperFirstChar(this string value)
    {
        if (string.IsNullOrEmpty(value))
        {
            return string.Empty;
        }

        return char.ToUpper(value.First()) + value[1..];
    }

    public static string AppendQuotes(this string value)
    {
        return string.IsNullOrEmpty(value) ? string.Empty : $"\"{value}\"";
    }

    public static int ToInt(this string? value, int defaultValue = 0)
    {
        return int.TryParse(value, out var result) ? result : defaultValue;
    }

    public static List<string> AppendEmpty(this IEnumerable<string> source)
    {
        return source.Concat(new[] { string.Empty }).ToList();
    }

    public static bool IsGroupType(this EConfigType configType)
    {
        return configType is EConfigType.PolicyGroup or EConfigType.ProxyChain;
    }

    public static bool IsComplexType(this EConfigType configType)
    {
        return configType is EConfigType.Custom or EConfigType.Outbound or EConfigType.PolicyGroup or EConfigType.ProxyChain;
    }

    /// <summary>
    /// Safely adds elements from a collection to the list. Does nothing if the source is null.
    /// </summary>
    public static void AddRangeSafe<T>(this ICollection<T> destination, IEnumerable<T>? source)
    {
        ArgumentNullException.ThrowIfNull(destination);

        if (source is null)
        {
            return;
        }

        if (destination is List<T> list)
        {
            list.AddRange(source);
            return;
        }

        foreach (var item in source)
        {
            destination.Add(item);
        }
    }

    /// <summary>
    /// Replace all cross-platform newline characters with the specified string
    /// </summary>
    public static string ReplaceLineBreaks(this string input, string replacement)
    {
        if (string.IsNullOrEmpty(input))
        {
            return input;
        }

        // You must replace \r\n first, and then replace the single characters \r and \n.
        return input.Replace("\r\n", replacement)
                    .Replace("\r", replacement)
                    .Replace("\n", replacement);
    }
}