ModernUO/Projects/UOContent/Commands/Logging.cs
Kamron Batman 61e41df00c
feat: Add zero-alloc interpolation handler to ValueStringBuilder, replace all StringBuilder usage (#2387)
## Summary

- **Add a self-referencing `InterpolationHandler` to `ValueStringBuilder`** that writes directly into the builder's buffer — zero intermediate allocation, works with `stackalloc`-backed builders
- **Replace all `System.Text.StringBuilder` usage** across the codebase with `ValueStringBuilder`
- **Convert `ValueStringBuilder.Create()` to `stackalloc`** at 10 sites where output length is provably bounded
- **Convert manual `Dispose()` to `using var`** where possible, and hoist loop-scoped builders outside loops with `Reset()`
- **Convert verbose `Append()` chains to `Append($"...")`** interpolation for readability
- **Add comprehensive documentation** for string handling patterns

## InterpolationHandler Design

`ValueStringBuilder` is a `ref struct`, which creates challenges for C#'s interpolated string handler pattern:

- **`ref` fields to ref structs are not allowed** (CS9050)
- **`[InterpolatedStringHandlerArgument("")]` passes struct receivers by value**, not by ref
- **`ISelfInterpolatedStringHandler` requires boxing** ref structs into interface fields

**Solution: Copy-and-reconcile pattern.** The handler receives a value copy of the builder. The copy shares the same underlying `char` buffer (`Span` points to the same `stackalloc`/pooled memory), so writes go to the original buffer. `Append()` reconciles by `this = handler._builder`, updating `_length` and any buffer references changed by `Grow()`.

This is safe because:
- The game loop is single-threaded — no concurrent access between handler construction and reconciliation
- If `Grow()` occurs in the copy, the original's stale buffer isn't accessed until `Append()` replaces it
- `Dispose()` correctly returns the reconciled buffer to the pool

## Changes by Category

### ValueStringBuilder (`Projects/Server/Buffers/ValueStringBuilder.cs`)
- Added nested `InterpolationHandler` ref struct with copy-and-reconcile pattern
- Added `Append([InterpolatedStringHandlerArgument("")] scoped ref InterpolationHandler)` method
- Removed `RawInterpolatedStringHandler` overloads (new handler replaces them)
- All `AppendFormatted` overloads delegate to existing `Append` methods (no code duplication)
- Alignment support via direct private field access (nested type privilege)

### StringBuilder → ValueStringBuilder (15 files)
Replaced all `new StringBuilder()` with `ValueStringBuilder.Create()` or `stackalloc`:
- ConPVP games: KingOfTheHill, DoubleDom, CTF, BombingRun, TourneyMatch
- ConPVP infrastructure: Tournament, Participant, TourneyParticipant
- ConPVP gumps: ArenaGump, TournamentBracketGump, AcceptTeamGump, ConfirmSignupGump
- Commands: Handlers, Logging, Add
- Other: TownCrier, SpeechLogGump, TestCenter

Key patterns:
- `sb = new StringBuilder()` reassignment → `sb.Reset()`
- `sb.AppendFormat("{0:N0}", value)` → `sb.Append($"{value:N0}")`
- `sb.Append(x).Append(y)` chains → separate statements (VSB returns void)

### Create() → stackalloc (10 files)
Converted heap-allocated builders to stackalloc where output is bounded:
- ClientVersion (32), MapSelection (160), HouseRaffleStone (48)
- HolySense (96), UnholySense (96), ClientVerification (192)
- AcceptTeamGump (64), ConfirmSignupGump (64)
- BaseWeapon (160), BaseArmor (128)

### Loop optimizations (2 files)
Hoisted `ValueStringBuilder` creation outside loops with `Reset()` per iteration:
- TourneyMatch.cs: `using var` inside for loop → stackalloc before loop
- ArenaGump.cs: `Create()` + `Dispose()` per iteration → stackalloc before loop

### Append chain → interpolation (5 files)
Converted multi-line `Append()` chains to `Append($"...")`:
- BountyMessage.cs: title switch (6 cases), paragraph (15→1 Append), description lines, closing
- AcceptTeamGump, ConfirmSignupGump, TournamentBracketGump: tournament type strings
- AdminGump: comment/tag formatting in loops

### Documentation
- `dev-docs/string-handling.md`: Full reference — construction, interpolation, disposal, decision guide
- `dev-docs/claude-skills/modernuo-string-handling.md`: Claude skill with quick reference
- `CLAUDE.md`: Added rule 17 (no StringBuilder), dev-docs table entry, skills table entry
- `dev-docs/code-standards.md`: Updated memory management section

## Test Plan

- [x] `dotnet build` — 0 errors, 0 warnings
- [x] `dotnet test` — 940/940 tests pass
- [x] 28 ValueStringBuilder tests covering all reconciliation scenarios:
  - Stackalloc no-grow, stackalloc with grow (→pool transition)
  - Heap no-grow, heap with grow, heap double grow
  - Pre-existing content with and without grow
  - Sequential multiple `Append($"...")` calls
  - Mixed plain + interpolated Append
  - Empty interpolation, literal-only, format specifiers
  - Null string holes, ISpanFormattable types
  - Dispose after stackalloc→pool grow
2026-03-22 14:23:44 -07:00

135 lines
3.8 KiB
C#

using System.IO;
using Server.Accounting;
using Server.Text;
namespace Server.Commands
{
public static class CommandLogging
{
private static readonly char[] m_NotSafe = { '\\', '/', ':', '*', '?', '"', '<', '>', '|' };
public static bool Enabled { get; set; } = true;
public static StreamWriter Output { get; private set; }
public static void Initialize()
{
EventSink.Command += EventSink_Command;
if (!Directory.Exists("Logs"))
{
Directory.CreateDirectory("Logs");
}
var directory = "Logs/Commands";
if (!Directory.Exists(directory))
{
Directory.CreateDirectory(directory);
}
try
{
Output = new StreamWriter(Path.Combine(directory, $"{Core.Now.ToLongDateString()}.log"), true);
Output.AutoFlush = true;
Output.WriteLine("##############################");
Output.WriteLine("Log started on {0}", Core.Now);
Output.WriteLine();
}
catch
{
// ignored
}
}
public static object Format(object o) =>
o switch
{
Mobile m => m.Account == null ? $"{m} (no account)" : $"{m} ('{m.Account.Username}')",
Item item => $"{item.Serial} ({item.GetType().Name})",
_ => o
};
public static void WriteLine(Mobile from, string text)
{
if (!Enabled)
{
return;
}
try
{
Output.WriteLine("{0}: {1}: {2}", Core.Now, from.NetState, text);
var path = Core.BaseDirectory;
var name = from.Account is not Account acct ? from.Name : acct.Username;
AppendPath(ref path, "Logs");
AppendPath(ref path, "Commands");
AppendPath(ref path, from.AccessLevel.ToString());
path = Path.Combine(path, $"{name}.log");
using var sw = new StreamWriter(path, true);
sw.WriteLine("{0}: {1}: {2}", Core.Now, from.NetState, text);
}
catch
{
// ignored
}
}
public static void AppendPath(ref string path, string toAppend)
{
path = Path.Combine(path, toAppend);
if (!Directory.Exists(path))
{
Directory.CreateDirectory(path);
}
}
public static string Safe(string ip)
{
if (ip == null)
{
return "null";
}
ip = ip.Trim().DefaultIfNullOrEmpty("empty");
var isSafe = true;
for (var i = 0; isSafe && i < m_NotSafe.Length; ++i)
{
isSafe = !ip.ContainsOrdinal(m_NotSafe[i]);
}
if (isSafe)
{
return ip;
}
using var sb = ValueStringBuilder.Create(ip.Length);
sb.Append(ip);
for (var i = 0; i < m_NotSafe.Length; ++i)
{
sb.Replace(m_NotSafe[i], '_', 0, sb.Length);
}
return sb.ToString();
}
public static void EventSink_Command(CommandEventArgs e)
{
var from = e.Mobile;
WriteLine(from, $"{from.AccessLevel} {Format(from)} used command '{e.Command} {e.ArgString}'");
}
public static void LogChangeProperty(Mobile from, object o, string name, string value)
{
WriteLine(from, $"{from.AccessLevel} {Format(from)} set property '{name}' of {Format(o)} to '{value}'");
}
}
}