Switched all uses of DateTime.Now to a slightly safer version

IPA.Injector/Backups/BackupUnit.cs

@@ -1,4 +1,5 @@
-using System;
+using IPA.Utilities;
+using System;
 using System.Collections.Generic;
 using System.IO;
 
@@ -16,7 +17,7 @@ namespace IPA.Injector.Backups
         private readonly FileInfo _manifestFile;
         private const string ManifestFileName = "$manifest$.txt";
 
-        public BackupUnit(string dir) : this(dir, DateTime.Now.ToString("yyyy-MM-dd_h-mm-ss"))
+        public BackupUnit(string dir) : this(dir, Utils.CurrentTime().ToString("yyyy-MM-dd_h-mm-ss"))
         {
         }
 

IPA.Loader/Config/Config.cs

@@ -212,7 +212,7 @@ namespace IPA.Config
                     try
                     {
                         provider.Item2.Save();
-                        provider.Item1.Value = DateTime.Now;
+                        provider.Item1.Value = Utils.CurrentTime();
                     }
                     catch (Exception e)
                     {

IPA.Loader/Logging/Printers/GlobalLogFilePrinter.cs

@@ -1,4 +1,5 @@
-using System;
+using IPA.Utilities;
+using System;
 using System.IO;
 
 namespace IPA.Logging.Printers
@@ -35,7 +36,7 @@ namespace IPA.Logging.Printers
         {
             var logsDir = new DirectoryInfo("Logs");
             logsDir.Create();
-            var finfo = new FileInfo(Path.Combine(logsDir.FullName, $"{DateTime.Now:yyyy.MM.dd.HH.mm.ss}.log"));
+            var finfo = new FileInfo(Path.Combine(logsDir.FullName, $"{Utils.CurrentTime():yyyy.MM.dd.HH.mm.ss}.log"));
             return finfo;
         }
     }

IPA.Loader/Logging/Printers/PluginLogFilePrinter.cs

@@ -1,4 +1,5 @@
-using System;
+using IPA.Utilities;
+using System;
 using System.IO;
 
 namespace IPA.Logging.Printers
@@ -24,7 +25,7 @@ namespace IPA.Logging.Printers
         {
             var logsDir = new DirectoryInfo(Path.Combine("Logs", name));
             logsDir.Create();
-            var finfo = new FileInfo(Path.Combine(logsDir.FullName, $"{DateTime.Now:yyyy.MM.dd.HH.mm.ss}.log"));
+            var finfo = new FileInfo(Path.Combine(logsDir.FullName, $"{Utils.CurrentTime():yyyy.MM.dd.HH.mm.ss}.log"));
             return finfo;
         }
 

IPA.Loader/Logging/Printers/PluginSubLogPrinter.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using IPA.Utilities;
 
 namespace IPA.Logging.Printers
 {
@@ -25,7 +26,7 @@ namespace IPA.Logging.Printers
         {
             var logsDir = new DirectoryInfo(Path.Combine("Logs", mainName, name));
             logsDir.Create();
-            var finfo = new FileInfo(Path.Combine(logsDir.FullName, $"{DateTime.Now:yyyy.MM.dd.HH.mm.ss}.log"));
+            var finfo = new FileInfo(Path.Combine(logsDir.FullName, $"{Utils.CurrentTime():yyyy.MM.dd.HH.mm.ss}.log"));
             return finfo;
         }
 

IPA.Loader/Logging/StandardLogger.cs

@@ -1,5 +1,6 @@
 using IPA.Config;
 using IPA.Logging.Printers;
+using IPA.Utilities;
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
@@ -194,7 +195,7 @@ namespace IPA.Logging
                 Level = level,
                 Message = message,
                 Logger = this,
-                Time = DateTime.Now
+                Time = Utils.CurrentTime()
             });
         }
 
@@ -285,7 +286,7 @@ namespace IPA.Logging
                                 }
 
                                 // update last use time and print
-                                printer.LastUse = DateTime.Now;
+                                printer.LastUse = Utils.CurrentTime();
                                 printer.Print(msg.Level, msg.Time, msg.Logger.logName, msg.Message);
                             }
                         }
@@ -328,14 +329,14 @@ namespace IPA.Logging
                             Level = Level.Warning,
                             Logger = loggerLogger,
                             Message = $"{loggerLogger.logName.ToUpper()}: Messages omitted to improve performance",
-                            Time = DateTime.Now
+                            Time = Utils.CurrentTime()
                         });
 
                         // resume log calls
                         logWaitEvent.Set();
                     }
 
-                    var now = DateTime.Now;
+                    var now = Utils.CurrentTime();
                     var copy = new List<LogPrinter>(started);
                     foreach (var printer in copy)
                     {

IPA.Loader/Utilities/Utils.cs

@@ -129,5 +129,42 @@ namespace IPA.Utilities
                 CopyAll(diSourceSubDir, nextTargetSubDir, appendFileName, onCopyException);
             }
         }
+
+        /// <summary>
+        /// Whether you can safely use <see cref="DateTime.Now"/> without Mono throwing a fit.
+        /// </summary>
+        /// <value><see langword="true"/> if you can use <see cref="DateTime.Now"/> safely, <see langword="false"/> otherwise</value>
+        public static bool CanUseDateTimeNowSafely { get; private set; } = true;
+        private static bool DateTimeSafetyUnknown = true;
+        private static ulong UnsafeAdvanceTicks = 1;
+
+        /// <summary>
+        /// Gets the current <see cref="DateTime"/> if supported, otherwise, if Mono would throw a fit,
+        /// returns <see cref="DateTime.MinValue"/> plus some value, such that each time it is called
+        /// the value will be greater than the previous result. Not suitable for timing.
+        /// </summary>
+        /// <returns>the current <see cref="DateTime"/> if supported, otherwise some indeterminant increasing value.</returns>
+        public static DateTime CurrentTime()
+        {
+            if (DateTimeSafetyUnknown)
+            {
+                DateTime time = DateTime.MinValue;
+                try
+                {
+                    time = DateTime.Now;
+                }
+                catch (TimeZoneNotFoundException)
+                { // Mono did a fucky wucky and we need to avoid this call
+                    CanUseDateTimeNowSafely = false;
+                }
+                DateTimeSafetyUnknown = false;
+                return time;
+            }
+            else
+            {
+                if (CanUseDateTimeNowSafely) return DateTime.Now;
+                else return DateTime.MinValue.AddTicks((long)UnsafeAdvanceTicks++); // return MinValue as a fallback
+            }
+        }
     }
 }