FileNameTimeSequence.cs

using System;
using System.IO;
 
namespace Waher.Runtime.IO
{
    public class FileNameTimeSequence
    {
        public const string DefaultYearPlaceholder = "%YEAR%";
 
        public const string DefaultMonthPlaceholder = "%MONTH%";
 
        public const string DefaultDayPlaceholder = "%DAY%";
 
        public const string DefaultHourPlaceholder = "%HOUR%";
 
        public const string DefaultMinutePlaceholder = "%MINUTE%";
 
        public const string DefaultSecondPlaceholder = "%SECOND%";
 
        private static readonly object systemSynchObject = new object();
 
        private readonly bool utc;
        private readonly string fileNamePattern;
        private readonly string placeholderYear;
        private readonly string placeholderMonth;
        private readonly string placeholderDay;
        private readonly string placeholderHour;
        private readonly string placeholderMinute;
        private readonly string placeholderSecond;
        private readonly bool usesYearPlaceholder;
        private readonly bool usesMonthPlaceholder;
        private readonly bool usesDayPlaceholder;
        private readonly bool usesHourPlaceholder;
        private readonly bool usesMinutePlaceholder;
        private readonly bool usesSecondPlaceholder;
        private DateTime last = DateTime.MinValue;
        private bool hasLast = false;
 
 
        public FileNameTimeSequence(string FileNamePattern)
            : this(FileNamePattern, true)
        {
        }
 
        public FileNameTimeSequence(string FileNamePattern, bool Utc)
            : this(FileNamePattern, Utc, DefaultYearPlaceholder, DefaultMonthPlaceholder,
                  DefaultDayPlaceholder, DefaultHourPlaceholder, DefaultMinutePlaceholder,
                  DefaultSecondPlaceholder)
        {
        }
 
        public FileNameTimeSequence(string FileNamePattern,
            string YearPlaceholder, string MonthPlaceholder, string DayPlaceholder,
            string HourPlaceholder, string MinutePlaceholder, string SecondPlaceholder)
            : this(FileNamePattern, true, YearPlaceholder, MonthPlaceholder, DayPlaceholder,
                HourPlaceholder, MinutePlaceholder, SecondPlaceholder)
        {
        }
 
        public FileNameTimeSequence(string FileNamePattern, bool Utc,
            string YearPlaceholder, string MonthPlaceholder, string DayPlaceholder,
            string HourPlaceholder, string MinutePlaceholder, string SecondPlaceholder)
        {
            this.fileNamePattern = FileNamePattern;
            this.utc = Utc;
 
            this.placeholderYear = YearPlaceholder;
            this.placeholderMonth = MonthPlaceholder;
            this.placeholderDay = DayPlaceholder;
            this.placeholderHour = HourPlaceholder;
            this.placeholderMinute = MinutePlaceholder;
            this.placeholderSecond = SecondPlaceholder;
 
            this.usesYearPlaceholder = !string.IsNullOrEmpty(this.placeholderYear) && this.fileNamePattern.Contains(this.placeholderYear);
            this.usesMonthPlaceholder = !string.IsNullOrEmpty(this.placeholderMonth) && this.fileNamePattern.Contains(this.placeholderMonth);
            this.usesDayPlaceholder = !string.IsNullOrEmpty(this.placeholderDay) && this.fileNamePattern.Contains(this.placeholderDay);
            this.usesHourPlaceholder = !string.IsNullOrEmpty(this.placeholderHour) && this.fileNamePattern.Contains(this.placeholderHour);
            this.usesMinutePlaceholder = !string.IsNullOrEmpty(this.placeholderMinute) && this.fileNamePattern.Contains(this.placeholderMinute);
            this.usesSecondPlaceholder = !string.IsNullOrEmpty(this.placeholderSecond) && this.fileNamePattern.Contains(this.placeholderSecond);
        }
 
        public bool Utc => this.utc;
 
        public string FileNamePattern => this.fileNamePattern;
 
        public string PlaceholderYear => this.placeholderYear;
 
        public string PlaceholderMonth => this.placeholderMonth;
 
        public string PlaceholderDay => this.placeholderDay;
 
        public string PlaceholderHour => this.placeholderHour;
 
        public string PlaceholderMinute => this.placeholderMinute;
 
        public string PlaceholderSecond => this.placeholderSecond;
 
        public bool UsesYearPlaceholder => this.usesYearPlaceholder;
 
        public bool UsesMonthPlaceholder => this.usesMonthPlaceholder;
 
        public bool UsesDayPlaceholder => this.usesDayPlaceholder;
 
        public bool UsesHourPlaceholder => this.usesHourPlaceholder;
 
        public bool UsesMinutePlaceholder => this.usesMinutePlaceholder;
 
        public bool UsesSecondPlaceholder => this.usesSecondPlaceholder;
 
        public DateTime Last => this.last;
 
        public static bool MakeUnique(ref string FileName)
        {
            if (File.Exists(FileName))
            {
                int i = FileName.LastIndexOf('.');
                if (i < 0)
                    i = FileName.Length;
 
                string FileName2;
                string Suffix;
                int j = 1;
 
                do
                {
                    j++;
                    Suffix = " (" + j.ToString() + ")";
 
                    FileName2 = FileName.Insert(i, Suffix);
                }
                while (File.Exists(FileName2) && j < 65536);
 
                if (j == 65536)
                    return false;
 
                FileName = FileName2;
            }
 
            return true;
        }
 
        public bool TryGetNewFileName(out string FileName)
        {
            DateTime TP = this.utc ? DateTime.UtcNow : DateTime.Now;
 
            if (!this.hasLast ||
                (this.usesSecondPlaceholder && this.last.Second != TP.Second) ||
                (this.usesMinutePlaceholder && this.last.Minute != TP.Minute) ||
                (this.usesHourPlaceholder && this.last.Hour != TP.Hour) ||
                (this.usesDayPlaceholder && this.last.Day != TP.Day) ||
                (this.usesMonthPlaceholder && this.last.Month != TP.Month) ||
                (this.usesYearPlaceholder && this.last.Year != TP.Year))
            {
                this.last = TP;
                this.hasLast = true;
 
                FileName = this.fileNamePattern;
 
                if (this.usesSecondPlaceholder)
                    FileName = FileName.Replace(this.placeholderSecond, TP.Second.ToString("D2"));
 
                if (this.usesMinutePlaceholder)
                    FileName = FileName.Replace(this.placeholderMinute, TP.Minute.ToString("D2"));
 
                if (this.usesHourPlaceholder)
                    FileName = FileName.Replace(this.placeholderHour, TP.Hour.ToString("D2"));
 
                if (this.usesDayPlaceholder)
                    FileName = FileName.Replace(this.placeholderDay, TP.Day.ToString("D2"));
 
                if (this.usesMonthPlaceholder)
                    FileName = FileName.Replace(this.placeholderMonth, TP.Month.ToString("D2"));
 
                if (this.usesYearPlaceholder)
                    FileName = FileName.Replace(this.placeholderYear, TP.Year.ToString("D4"));
 
                lock (systemSynchObject)
                {
                    if (!MakeUnique(ref FileName))
                        return false;
 
                    StreamWriter fs = File.CreateText(FileName);    // Creates a zero-byte file, to reserve the name,
                    fs.Close();
                    fs.Dispose();
                }
 
                return true;
            }
            else
            {
                FileName = null;
                return false;
            }
        }
    }
}