ModernUO/Projects/UOContent/Engines/ConPVP/Gumps/ArenaGump.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

282 lines
7.5 KiB
C#

using System.Collections.Generic;
using ModernUO.Serialization;
using Server.Gumps;
using Server.Mobiles;
using Server.Network;
using Server.Text;
namespace Server.Engines.ConPVP;
[SerializationGenerator(0, false)]
public partial class ArenasMoongate : Item
{
[Constructible]
public ArenasMoongate() : base(0x1FD4)
{
Movable = false;
Light = LightType.Circle300;
}
public override string DefaultName => "arena moongate";
public bool UseGate(Mobile from)
{
if (DuelContext.CheckCombat(from))
{
from.SendMessage(0x22, "You have recently been in combat with another player and cannot use this moongate.");
return false;
}
if (from.Spell != null)
{
from.SendLocalizedMessage(1049616); // You are too busy to do that at the moment.
return false;
}
from.SendGump(new ArenaGump(from, this));
if (!from.Hidden || from.AccessLevel == AccessLevel.Player)
{
Effects.PlaySound(from.Location, from.Map, 0x20E);
}
return true;
}
public override void OnDoubleClick(Mobile from)
{
if (from.InRange(GetWorldLocation(), 1))
{
UseGate(from);
}
else
{
from.LocalOverheadMessage(MessageType.Regular, 0x3B2, 1019045); // I can't reach that
}
}
public override bool OnMoveOver(Mobile m) => !m.Player || UseGate(m);
}
public class ArenaGump : Gump
{
private readonly List<Arena> m_Arenas;
private readonly Mobile m_From;
private readonly ArenasMoongate m_Gate;
private int m_ColumnX = 12;
public override bool Singleton => true;
public ArenaGump(Mobile from, ArenasMoongate gate) : base(50, 50)
{
m_From = from;
m_Gate = gate;
m_Arenas = Arena.Arenas;
AddPage(0);
var height = 12 + 20 + m_Arenas.Count * 31 + 24 + 12;
AddBackground(0, 0, 499 + 40, height, 0x2436);
var list = m_Arenas;
for (var i = 1; i < list.Count; i += 2)
{
AddImageTiled(12, 32 + i * 31, 475 + 40, 30, 0x2430);
}
AddAlphaRegion(10, 10, 479 + 40, height - 20);
AddColumnHeader(35, null);
AddColumnHeader(115, "Arena");
AddColumnHeader(325, "Participants");
AddColumnHeader(40, "Obs");
AddButton(499 + 40 - 12 - 63 - 4 - 63, height - 12 - 24, 247, 248, 1);
AddButton(499 + 40 - 12 - 63, height - 12 - 24, 241, 242, 2);
var sb = new ValueStringBuilder(stackalloc char[256]);
for (var i = 0; i < list.Count; ++i)
{
var ar = list[i];
var x = 12;
var y = 32 + i * 31;
var color = ar.Players.Count > 0 ? 0xCCFFCC : 0xCCCCCC;
AddRadio(x + 3, y + 1, 9727, 9730, false, i);
x += 35;
AddBorderedText(x + 5, y + 5, 115 - 5, ar.Name ?? "(no name)", color, 0);
x += 115;
sb.Reset();
if (ar.Players.Count > 0)
{
var ladder = Ladder.Instance;
if (ladder == null)
{
continue;
}
LadderEntry p1 = null, p2 = null, p3 = null, p4 = null;
for (var j = 0; j < ar.Players.Count; ++j)
{
var mob = ar.Players[j];
var c = ladder.Find(mob);
if (p1 == null || c.Index < p1.Index)
{
p4 = p3;
p3 = p2;
p2 = p1;
p1 = c;
}
else if (p2 == null || c.Index < p2.Index)
{
p4 = p3;
p3 = p2;
p2 = c;
}
else if (p3 == null || c.Index < p3.Index)
{
p4 = p3;
p3 = c;
}
else if (p4 == null || c.Index < p4.Index)
{
p4 = c;
}
}
Append(ref sb, p1);
Append(ref sb, p2);
Append(ref sb, p3);
Append(ref sb, p4);
if (ar.Players.Count > 4)
{
sb.Append(", ...");
}
}
else
{
sb.Append("Empty");
}
AddBorderedText(x + 5, y + 5, 325 - 5, sb.ToString(), color, 0);
x += 325;
AddBorderedText(x, y + 5, 40, Html.Center($"{ar.Spectators}"), color, 0);
}
sb.Dispose();
}
private void Append(ref ValueStringBuilder sb, LadderEntry le)
{
if (le == null)
{
return;
}
if (sb.Length > 0)
{
sb.Append(", ");
}
sb.Append(le.Mobile.Name);
}
public override void OnResponse(NetState sender, in RelayInfo info)
{
if (info.ButtonID != 1)
{
return;
}
var switches = info.Switches;
if (switches.Length == 0)
{
return;
}
var opt = switches[0];
if (opt < 0 || opt >= m_Arenas.Count)
{
return;
}
var arena = m_Arenas[opt];
if (!m_From.InRange(m_Gate.GetWorldLocation(), 1) || m_From.Map != m_Gate.Map)
{
m_From.SendLocalizedMessage(1019002); // You are too far away to use the gate.
}
else if (DuelContext.CheckCombat(m_From))
{
m_From.SendMessage(
0x22,
"You have recently been in combat with another player and cannot use this moongate."
);
}
else if (m_From.Spell != null)
{
m_From.SendLocalizedMessage(1049616); // You are too busy to do that at the moment.
}
else if (m_From.Map == arena.Facet && arena.Zone.Contains(m_From.Location))
{
m_From.SendLocalizedMessage(1019003); // You are already there.
}
else
{
BaseCreature.TeleportPets(m_From, arena.GateIn, arena.Facet);
m_From.Combatant = null;
m_From.Warmode = false;
m_From.Hidden = true;
m_From.MoveToWorld(arena.GateIn, arena.Facet);
Effects.PlaySound(arena.GateIn, arena.Facet, 0x1FE);
}
}
private void AddBorderedText(int x, int y, int width, string text, int color, int borderColor)
{
/*AddColoredText( x - 1, y, width, text, borderColor );
AddColoredText( x + 1, y, width, text, borderColor );
AddColoredText( x, y - 1, width, text, borderColor );
AddColoredText( x, y + 1, width, text, borderColor );*/
/*AddColoredText( x - 1, y - 1, width, text, borderColor );
AddColoredText( x + 1, y + 1, width, text, borderColor );*/
AddColoredText(x, y, width, text, color);
}
private void AddColoredText(int x, int y, int width, string text, int color)
{
AddHtml(x, y, width, 20, color == 0 ? text : text.Color(color));
}
private void AddColumnHeader(int width, string name)
{
AddBackground(m_ColumnX, 12, width, 20, 0x242C);
AddImageTiled(m_ColumnX + 2, 14, width - 4, 16, 0x2430);
if (name != null)
{
AddBorderedText(m_ColumnX, 13, width, name.Center(), 0xFFFFFF, 0);
}
m_ColumnX += width;
}
}