From e6c696fa6b0bfe5ef013e1179765ce1dcb071c38 Mon Sep 17 00:00:00 2001
From: Jesse Plamondon-Willard <Pathoschild@users.noreply.github.com>
Date: Tue, 19 Apr 2022 19:11:58 -0400
Subject: [PATCH] add immutable stack trace to cache stack info

---
 .../Deprecations/DeprecationManager.cs        |  4 +-
 .../Deprecations/DeprecationWarning.cs        |  4 +-
 .../Deprecations/ImmutableStackTrace.cs       | 53 +++++++++++++++++++
 3 files changed, 57 insertions(+), 4 deletions(-)
 create mode 100644 src/SMAPI/Framework/Deprecations/ImmutableStackTrace.cs

diff --git a/src/SMAPI/Framework/Deprecations/DeprecationManager.cs b/src/SMAPI/Framework/Deprecations/DeprecationManager.cs
index da17ce7e..84ce2132 100644
--- a/src/SMAPI/Framework/Deprecations/DeprecationManager.cs
+++ b/src/SMAPI/Framework/Deprecations/DeprecationManager.cs
@@ -63,7 +63,7 @@ namespace StardewModdingAPI.Framework.Deprecations
                 return;
 
             // queue warning
-            var stack = new StackTrace(skipFrames: 1); // skip this method
+            ImmutableStackTrace stack = ImmutableStackTrace.Get(skipFrames: 1);
             this.QueuedWarnings.Add(new DeprecationWarning(source, nounPhrase, version, severity, stack));
         }
 
@@ -134,7 +134,7 @@ namespace StardewModdingAPI.Framework.Deprecations
         /// <summary>Get the simplest stack trace which shows where in the mod the deprecated code was called from.</summary>
         /// <param name="stack">The stack trace.</param>
         /// <param name="mod">The mod for which to show a stack trace.</param>
-        private string GetSimplifiedStackTrace(StackTrace stack, IModMetadata? mod)
+        private string GetSimplifiedStackTrace(ImmutableStackTrace stack, IModMetadata? mod)
         {
             // unknown mod, show entire stack trace
             if (mod == null)
diff --git a/src/SMAPI/Framework/Deprecations/DeprecationWarning.cs b/src/SMAPI/Framework/Deprecations/DeprecationWarning.cs
index 38062daf..e00881b1 100644
--- a/src/SMAPI/Framework/Deprecations/DeprecationWarning.cs
+++ b/src/SMAPI/Framework/Deprecations/DeprecationWarning.cs
@@ -24,7 +24,7 @@ namespace StardewModdingAPI.Framework.Deprecations
         public DeprecationLevel Level { get; }
 
         /// <summary>The stack trace when the deprecation warning was raised.</summary>
-        public StackTrace StackTrace { get; }
+        public ImmutableStackTrace StackTrace { get; }
 
 
         /*********
@@ -36,7 +36,7 @@ namespace StardewModdingAPI.Framework.Deprecations
         /// <param name="version">The SMAPI version which deprecated it.</param>
         /// <param name="level">The deprecation level for the affected code.</param>
         /// <param name="stackTrace">The stack trace when the deprecation warning was raised.</param>
-        public DeprecationWarning(IModMetadata? mod, string nounPhrase, string version, DeprecationLevel level, StackTrace stackTrace)
+        public DeprecationWarning(IModMetadata? mod, string nounPhrase, string version, DeprecationLevel level, ImmutableStackTrace stackTrace)
         {
             this.Mod = mod;
             this.NounPhrase = nounPhrase;
diff --git a/src/SMAPI/Framework/Deprecations/ImmutableStackTrace.cs b/src/SMAPI/Framework/Deprecations/ImmutableStackTrace.cs
new file mode 100644
index 00000000..059d871c
--- /dev/null
+++ b/src/SMAPI/Framework/Deprecations/ImmutableStackTrace.cs
@@ -0,0 +1,53 @@
+using System.Diagnostics;
+
+namespace StardewModdingAPI.Framework.Deprecations
+{
+    /// <summary>An immutable stack trace that caches its values.</summary>
+    internal class ImmutableStackTrace
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>The underlying stack trace.</summary>
+        private readonly StackTrace StackTrace;
+
+        /// <summary>The individual method calls in the stack trace.</summary>
+        private StackFrame[]? Frames;
+
+        /// <summary>The string representation of the stack trace.</summary>
+        private string? StringForm;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="stackTrace">The underlying stack trace.</param>
+        public ImmutableStackTrace(StackTrace stackTrace)
+        {
+            this.StackTrace = stackTrace;
+        }
+
+        /// <summary>Get the underlying frames.</summary>
+        /// <remarks>This is a reference to the underlying stack frames, so this array should not be edited.</remarks>
+        public StackFrame[] GetFrames()
+        {
+            return this.Frames ??= this.StackTrace.GetFrames();
+        }
+
+        /// <inheritdoc />
+        public override string ToString()
+        {
+            return this.StringForm ??= this.StackTrace.ToString();
+        }
+
+        /// <summary>Get the current stack trace.</summary>
+        /// <param name="skipFrames">The number of frames up the stack from which to start the trace.</param>
+        public static ImmutableStackTrace Get(int skipFrames = 0)
+        {
+            return new ImmutableStackTrace(
+                new StackTrace(skipFrames: skipFrames + 1) // also skip this method
+            );
+        }
+    }
+}