Files
Media.JoshHeaps.Net/Media.JoshHeaps.Net/Services/BreadboardValidator.cs
T
2026-08-18 12:18:54 -06:00

974 lines
35 KiB
C#

using System.Text;
using System.Text.Json;
using System.Text.RegularExpressions;
namespace Media.JoshHeaps.Net.Services;
/// <summary>
/// Outcome of validating a breadboard circuit document. Errors are terse
/// machine-readable "path:reason" tokens that are safe to return to the client:
/// they never echo unbounded user input, file paths, or exception detail.
/// </summary>
public sealed record BreadboardValidationResult(bool IsValid, IReadOnlyList<string> Errors)
{
public static BreadboardValidationResult Ok() => new(true, Array.Empty<string>());
public static BreadboardValidationResult Fail(IReadOnlyList<string> errors) => new(false, errors);
}
/// <summary>
/// Server-side structural validation of the circuit JSONB document (schema v1)
/// before persistence. Never throws for expected-invalid input — malformed JSON,
/// wrong types, missing fields and out-of-range values all come back as errors.
/// Stateless and thread-safe.
/// </summary>
public class BreadboardValidator(ILogger<BreadboardValidator> logger)
{
/// <summary>Only schema version 1 exists in milestone 1.</summary>
public const int SupportedVersion = 1;
/// <summary>Hard cap on the raw UTF-8 size of the circuit document (2 MB, per the team contract).</summary>
public const int MaxCircuitBytes = 2 * 1024 * 1024;
/// <summary>A realistic desk holds a handful of boards; 50 is generous and bounds net extraction cost.</summary>
public const int MaxBoards = 50;
/// <summary>Team amendment A11: pinned to the JS shared/ constants. Higher counts could exceed the 2 MB byte cap.</summary>
public const int MaxComponents = 3000;
/// <summary>Team amendment A11: pinned to the JS shared/ constants, and bounds union-find work in the engine.</summary>
public const int MaxWires = 10000;
/// <summary>Per the schema contract: any string up to 40 chars.</summary>
public const int MaxUidLength = 40;
/// <summary>The deepest legal path in schema v1 is 6 (circuit > components > component > props > to > value), so 8 is ample.</summary>
public const int MaxJsonDepth = 8;
/// <summary>No schema string is meaningfully longer than this; keeps a multi-megabyte "color" from being compared or echoed.</summary>
public const int MaxStringLength = 64;
/// <summary>Cap on returned errors so a hostile document cannot produce a huge response.</summary>
public const int MaxErrors = 50;
/// <summary>Full-size 830-point board: 63 columns in the main grid.</summary>
public const int MainColumnMin = 1;
public const int MainColumnMax = 63;
/// <summary>Each power rail exposes 50 tie points.</summary>
public const int RailIndexMin = 1;
public const int RailIndexMax = 50;
/// <summary>Board canvas positions are world-space pixels; anything beyond this is nonsense.</summary>
public const double MaxBoardCoordinate = 1_000_000d;
/// <summary>Resistance must be a positive, finite, physically plausible value.</summary>
public const double MaxResistorOhms = 1e9;
// Column footprints, mirrored from the frontend's shared/component-pins.js so a document
// the client accepts is a document the server accepts.
private const int ChipColumnSpan = 7; // 14-pin DIP
private const int DipSwitchColumnSpan = 8; // 16-pin DIP
private const int PushButtonColumnSpan = 3;
private const int TransistorColumnSpan = 3; // TO-92, three legs one column apart
private const int DipSwitchPositions = 8;
private static readonly Regex UidPattern = new($@"^[A-Za-z0-9_.:-]{{1,{MaxUidLength}}}$", RegexOptions.Compiled | RegexOptions.CultureInvariant);
private static readonly Regex HexColorPattern = new(@"^#(?:[0-9a-fA-F]{3}|[0-9a-fA-F]{6})$", RegexOptions.Compiled | RegexOptions.CultureInvariant);
private static readonly Regex SafeNamePattern = new(@"^[A-Za-z0-9_]{1,32}$", RegexOptions.Compiled | RegexOptions.CultureInvariant);
private static readonly HashSet<string> TopLevelKeys = new(StringComparer.Ordinal) { "version", "boards", "components", "wires" };
private static readonly HashSet<string> BoardKeys = new(StringComparer.Ordinal) { "uid", "x", "y" };
private static readonly HashSet<string> ComponentKeys = new(StringComparer.Ordinal) { "uid", "type", "anchor", "orient", "props" };
private static readonly HashSet<string> WireKeys = new(StringComparer.Ordinal) { "uid", "from", "to", "color" };
private static readonly HashSet<string> MainHoleKeys = new(StringComparer.Ordinal) { "board", "kind", "col", "row" };
private static readonly HashSet<string> RailHoleKeys = new(StringComparer.Ordinal) { "board", "kind", "rail", "index" };
private static readonly HashSet<string> MainRows = new(StringComparer.Ordinal) { "a", "b", "c", "d", "e", "f", "g", "h", "i", "j" };
/// <summary>Pin 1 of a gap-straddling package sits in one of the two rows flanking the centre channel.</summary>
private static readonly HashSet<string> GapAnchorRows = new(StringComparer.Ordinal) { "e", "f" };
private static readonly HashSet<string> RailNames = new(StringComparer.Ordinal) { "topPlus", "topMinus", "bottomPlus", "bottomMinus" };
private static readonly HashSet<string> Orientations = new(StringComparer.Ordinal) { "up", "down", "left", "right" };
/// <summary>A DIP package cannot straddle the gap vertically, so it has exactly two orientations 180 degrees apart.</summary>
private static readonly HashSet<string> PackageOrientations = new(StringComparer.Ordinal) { "left", "right" };
private static readonly HashSet<string> SupplySides = new(StringComparer.Ordinal) { "top", "bottom" };
private static readonly HashSet<string> NamedColors = new(StringComparer.Ordinal)
{
"red", "green", "blue", "yellow", "orange", "white", "amber", "purple", "black", "gray"
};
private static readonly HashSet<string> LedColors = new(StringComparer.Ordinal)
{
"red", "green", "blue", "yellow", "orange", "white", "amber", "purple"
};
private static readonly HashSet<string> DipChipTypes = new(StringComparer.Ordinal)
{
"74HC00", "74HC02", "74HC04", "74HC08", "74HC32", "74HC86", "74HC30"
};
private static readonly HashSet<string> ComponentTypes = new(StringComparer.Ordinal)
{
"led", "resistor", "diode", "npn", "pnp", "nmos", "pmos",
"pushButton", "dipSwitch8", "powerSupply5V",
"74HC00", "74HC02", "74HC04", "74HC08", "74HC32", "74HC86", "74HC30"
};
private static readonly HashSet<string> LedPropKeys = new(StringComparer.Ordinal) { "color" };
private static readonly HashSet<string> ResistorPropKeys = new(StringComparer.Ordinal) { "ohms", "to" };
private static readonly HashSet<string> DipSwitchPropKeys = new(StringComparer.Ordinal) { "on" };
private static readonly HashSet<string> SupplyPropKeys = new(StringComparer.Ordinal) { "board", "side" };
private static readonly HashSet<string> NoPropKeys = new(StringComparer.Ordinal);
/// <summary>
/// Validates the raw circuit JSON exactly as it will be persisted. This is the
/// only entry point, so the byte-size cap can never be bypassed.
/// </summary>
public BreadboardValidationResult Validate(string? circuitJson)
{
try
{
if (string.IsNullOrWhiteSpace(circuitJson))
{
return BreadboardValidationResult.Fail(["circuit:missing"]);
}
// Measured on UTF-8 bytes, before any parsing work is done.
if (Encoding.UTF8.GetByteCount(circuitJson) > MaxCircuitBytes)
{
return BreadboardValidationResult.Fail(["circuit:exceeds_max_size"]);
}
JsonDocument document;
try
{
document = JsonDocument.Parse(circuitJson, new JsonDocumentOptions
{
MaxDepth = MaxJsonDepth,
CommentHandling = JsonCommentHandling.Disallow,
AllowTrailingCommas = false
});
}
catch (JsonException)
{
return BreadboardValidationResult.Fail(["circuit:malformed_json"]);
}
using (document)
{
var errors = new ErrorList();
ValidateDocument(document.RootElement, errors);
return errors.HasErrors
? BreadboardValidationResult.Fail(errors.Build())
: BreadboardValidationResult.Ok();
}
}
catch (Exception ex)
{
logger.LogError(ex, "Unexpected failure validating breadboard circuit document");
return BreadboardValidationResult.Fail(["circuit:validation_failed"]);
}
}
private static void ValidateDocument(JsonElement circuit, ErrorList errors)
{
if (circuit.ValueKind != JsonValueKind.Object)
{
errors.Add("circuit", "not_an_object");
return;
}
CheckKeys(circuit, "circuit", TopLevelKeys, errors);
ValidateVersion(circuit, errors);
// uids are unique across the whole document, so a single set covers all three collections.
var allUids = new HashSet<string>(StringComparer.Ordinal);
var boardUids = ValidateBoards(circuit, allUids, errors);
ValidateComponents(circuit, boardUids, allUids, errors);
ValidateWires(circuit, boardUids, allUids, errors);
}
private static void ValidateVersion(JsonElement circuit, ErrorList errors)
{
if (!circuit.TryGetProperty("version", out var version))
{
errors.Add("version", "missing");
return;
}
if (version.ValueKind != JsonValueKind.Number || !version.TryGetInt32(out var value) || value != SupportedVersion)
{
errors.Add("version", "unsupported");
}
}
private static HashSet<string> ValidateBoards(JsonElement circuit, HashSet<string> allUids, ErrorList errors)
{
var boardUids = new HashSet<string>(StringComparer.Ordinal);
if (!TryGetArray(circuit, "boards", MaxBoards, errors, out var boards))
{
return boardUids;
}
var index = 0;
foreach (var board in boards.EnumerateArray())
{
var path = $"boards[{index++}]";
if (board.ValueKind != JsonValueKind.Object)
{
errors.Add(path, "not_an_object");
continue;
}
CheckKeys(board, path, BoardKeys, errors);
var uid = ReadUid(board, path, allUids, errors);
if (uid is not null)
{
boardUids.Add(uid);
}
ReadCoordinate(board, "x", path, errors);
ReadCoordinate(board, "y", path, errors);
}
return boardUids;
}
private static void ValidateComponents(JsonElement circuit, HashSet<string> boardUids, HashSet<string> allUids, ErrorList errors)
{
if (!TryGetArray(circuit, "components", MaxComponents, errors, out var components))
{
return;
}
// One supply per rail pair: two supplies on the same pair is a contradiction the
// engine would have to resolve as spurious contention.
var supplySlots = new HashSet<(string Board, string Side)>();
var index = 0;
foreach (var component in components.EnumerateArray())
{
var path = $"components[{index++}]";
if (component.ValueKind != JsonValueKind.Object)
{
errors.Add(path, "not_an_object");
continue;
}
CheckKeys(component, path, ComponentKeys, errors);
ReadUid(component, path, allUids, errors);
var type = ReadEnum(component, "type", path, ComponentTypes, errors, required: true);
if (type is null)
{
continue;
}
ValidateComponentByType(component, path, type, boardUids, supplySlots, errors);
}
}
/// <summary>
/// Every branch must account for `orient`, either by validating it or by rejecting it —
/// a key that is in <see cref="ComponentKeys"/> but unvalidated is an arbitrary
/// attacker-controlled slot in the stored document, which is exactly what the
/// unknown-property allowlist exists to prevent.
/// </summary>
private static void ValidateComponentByType(
JsonElement component,
string path,
string type,
HashSet<string> boardUids,
HashSet<(string Board, string Side)> supplySlots,
ErrorList errors)
{
switch (type)
{
case "led":
ValidateTwoHoleSpan(component, path, boardUids, errors);
ValidateLedProps(component, path, errors);
break;
case "diode":
ValidateTwoHoleSpan(component, path, boardUids, errors);
ValidateEmptyProps(component, path, errors);
break;
case "npn":
case "pnp":
case "nmos":
case "pmos":
ValidateInlinePackage(component, path, TransistorColumnSpan, boardUids, errors);
ValidateEmptyProps(component, path, errors);
break;
case "resistor":
// The second terminal is explicit in props.to, so orientation is derived, not stored.
ReadAnchor(component, path, boardUids, errors, required: true);
RequireAbsent(component, "orient", path, errors);
ValidateResistorProps(component, path, boardUids, errors);
break;
case "pushButton":
ValidateGapPackage(component, path, PushButtonColumnSpan, boardUids, errors);
ValidateEmptyProps(component, path, errors);
break;
case "dipSwitch8":
ValidateGapPackage(component, path, DipSwitchColumnSpan, boardUids, errors);
ValidateDipSwitchProps(component, path, errors);
break;
case "powerSupply5V":
// Anchorless: both pins are derived from props, so an anchor would be meaningless data.
RequireAbsent(component, "anchor", path, errors);
RequireAbsent(component, "orient", path, errors);
ValidateSupplyProps(component, path, boardUids, supplySlots, errors);
break;
default:
// Reachable only if a type is added to ComponentTypes without a case here:
// a registry/dispatch drift then fails closed instead of skipping validation.
if (DipChipTypes.Contains(type))
{
ValidateGapPackage(component, path, ChipColumnSpan, boardUids, errors);
ValidateEmptyProps(component, path, errors);
}
else
{
errors.Add($"{path}.type", "unsupported");
}
break;
}
}
/// <summary>
/// A two-legged part spanning two holes: the anchor is the first terminal (an LED's anode,
/// a diode's anode) and the second sits one hole away in the orient direction. A leg in a
/// power rail is legal — electrically useless if both legs share a rail, but a real
/// breadboard allows it — so only the footprint is checked.
/// </summary>
private static void ValidateTwoHoleSpan(JsonElement component, string path, HashSet<string> boardUids, ErrorList errors)
{
var orient = ReadEnum(component, "orient", path, Orientations, errors, required: true);
var anchor = ReadAnchor(component, path, boardUids, errors, required: true);
if (anchor is null || orient is null)
{
return;
}
if (orient is "up" or "down")
{
// Vertical travel moves one row and may legitimately cross the centre channel. A
// rail has no rows, so the far leg of an up/down part anchored there has nowhere to go.
if (anchor.Kind != "main")
{
errors.Add($"{path}.orient", "not_valid_on_rail");
return;
}
// Rows a..j read top to bottom, so "up" decreases the row index — the same sign
// convention that maps "left"/"right" to -1/+1 on the column axis. Mirrors
// shared/board-geometry.js (team amendment A12 pins it as contract).
var farRow = (anchor.Row[0] - 'a') + (orient == "up" ? -1 : 1);
if (farRow < 0 || farRow >= MainRows.Count)
{
errors.Add($"{path}.anchor", "footprint_off_board");
}
return;
}
var farPosition = anchor.Position + (orient == "left" ? -1 : 1);
var min = anchor.Kind == "main" ? MainColumnMin : RailIndexMin;
var max = anchor.Kind == "main" ? MainColumnMax : RailIndexMax;
if (farPosition < min || farPosition > max)
{
errors.Add($"{path}.anchor", "footprint_off_board");
}
}
/// <summary>
/// A three-legged inline package (TO-92). Its legs run along one row of the main grid, one
/// column apart, so only "left" and "right" leave each leg in a strip of its own — a
/// vertical placement would put two legs in the same five-hole strip, and a power rail is
/// one continuous strip, which is why an anchor there is rejected outright.
/// </summary>
private static void ValidateInlinePackage(
JsonElement component,
string path,
int columnSpan,
HashSet<string> boardUids,
ErrorList errors)
{
var orient = ReadEnum(component, "orient", path, PackageOrientations, errors, required: true);
var anchor = ReadAnchor(component, path, boardUids, errors, required: true);
if (anchor is null || orient is null)
{
return;
}
if (anchor.Kind != "main")
{
errors.Add($"{path}.anchor.kind", "must_be_main");
return;
}
var lastColumn = anchor.Position + ((orient == "left" ? -1 : 1) * (columnSpan - 1));
if (lastColumn < MainColumnMin || lastColumn > MainColumnMax)
{
errors.Add($"{path}.anchor.col", "package_off_board");
}
}
/// <summary>
/// Packages that straddle the centre gap. Pin 1 sits in row "e" or "f" on the main grid
/// and the package runs across <paramref name="columnSpan"/> columns: row "e" reads left
/// to right, row "f" is the same package rotated 180 degrees and reads right to left.
/// Every pin must land on a real hole.
/// </summary>
private static void ValidateGapPackage(
JsonElement component,
string path,
int columnSpan,
HashSet<string> boardUids,
ErrorList errors)
{
var orient = ReadEnum(component, "orient", path, PackageOrientations, errors, required: true);
var anchor = ReadAnchor(component, path, boardUids, errors, required: true);
if (anchor is null)
{
return;
}
if (anchor.Kind != "main")
{
errors.Add($"{path}.anchor.kind", "must_be_main");
return;
}
if (!GapAnchorRows.Contains(anchor.Row))
{
errors.Add($"{path}.anchor.row", "must_straddle_gap");
return;
}
// Orientation and anchor row are redundant by construction, so a document carrying
// both is able to encode a contradiction. Reject that rather than pick a winner.
var step = anchor.Row == "e" ? 1 : -1;
if (orient is not null && orient != (step == 1 ? "right" : "left"))
{
errors.Add($"{path}.orient", "contradicts_anchor_row");
}
var lastColumn = anchor.Position + (step * (columnSpan - 1));
if (lastColumn < MainColumnMin || lastColumn > MainColumnMax)
{
errors.Add($"{path}.anchor.col", "package_off_board");
}
}
/// <summary>
/// Rejects a key that carries no meaning for this component type, so it cannot become an
/// unvalidated slot in the stored document. Presence is what is rejected, not just a
/// meaningful value: an explicit JSON null is a present property, and the editor's schema
/// refuses to load one, so accepting it here would persist a document the client cannot open.
/// </summary>
private static void RequireAbsent(JsonElement component, string name, string path, ErrorList errors)
{
if (component.TryGetProperty(name, out _))
{
errors.Add($"{path}.{name}", "not_applicable");
}
}
/// <summary>Saved switch positions, so a bank survives a reload. Optional; exactly eight booleans when present.</summary>
private static void ValidateDipSwitchProps(JsonElement component, string path, ErrorList errors)
{
if (!ReadProps(component, path, DipSwitchPropKeys, errors, required: false, out var props))
{
return;
}
if (!props.TryGetProperty("on", out var positions) || positions.ValueKind == JsonValueKind.Null)
{
return;
}
var onPath = $"{path}.props.on";
if (positions.ValueKind != JsonValueKind.Array)
{
errors.Add(onPath, "not_an_array");
return;
}
if (positions.GetArrayLength() != DipSwitchPositions)
{
errors.Add(onPath, "wrong_length");
return;
}
var index = 0;
foreach (var position in positions.EnumerateArray())
{
if (position.ValueKind is not (JsonValueKind.True or JsonValueKind.False))
{
errors.Add($"{onPath}[{index}]", "not_a_boolean");
}
index++;
}
}
private static void ValidateLedProps(JsonElement component, string path, ErrorList errors)
{
if (!ReadProps(component, path, LedPropKeys, errors, required: true, out var props))
{
return;
}
ReadColor(props, "color", $"{path}.props", LedColors, errors, required: true);
}
private static void ValidateResistorProps(JsonElement component, string path, HashSet<string> boardUids, ErrorList errors)
{
if (!ReadProps(component, path, ResistorPropKeys, errors, required: true, out var props))
{
return;
}
var propsPath = $"{path}.props";
if (!props.TryGetProperty("ohms", out var ohms))
{
errors.Add($"{propsPath}.ohms", "missing");
}
else if (ohms.ValueKind != JsonValueKind.Number || !ohms.TryGetDouble(out var value) || !double.IsFinite(value))
{
errors.Add($"{propsPath}.ohms", "not_a_number");
}
else if (value <= 0 || value > MaxResistorOhms)
{
errors.Add($"{propsPath}.ohms", "out_of_range");
}
// A resistor spans two holes and may reach across boards or onto a rail.
if (!props.TryGetProperty("to", out var to))
{
errors.Add($"{propsPath}.to", "missing");
}
else
{
ValidateHoleRef(to, $"{propsPath}.to", boardUids, errors);
}
}
private static void ValidateSupplyProps(
JsonElement component,
string path,
HashSet<string> boardUids,
HashSet<(string Board, string Side)> supplySlots,
ErrorList errors)
{
if (!ReadProps(component, path, SupplyPropKeys, errors, required: true, out var props))
{
return;
}
var propsPath = $"{path}.props";
var board = ValidateBoardReference(props, "board", propsPath, boardUids, errors);
var side = ReadEnum(props, "side", propsPath, SupplySides, errors, required: true);
if (board is not null && side is not null && !supplySlots.Add((board, side)))
{
errors.Add(propsPath, "rail_pair_already_supplied");
}
}
private static void ValidateEmptyProps(JsonElement component, string path, ErrorList errors)
{
ReadProps(component, path, NoPropKeys, errors, required: false, out _);
}
private static void ValidateWires(JsonElement circuit, HashSet<string> boardUids, HashSet<string> allUids, ErrorList errors)
{
if (!TryGetArray(circuit, "wires", MaxWires, errors, out var wires))
{
return;
}
var index = 0;
foreach (var wire in wires.EnumerateArray())
{
var path = $"wires[{index++}]";
if (wire.ValueKind != JsonValueKind.Object)
{
errors.Add(path, "not_an_object");
continue;
}
CheckKeys(wire, path, WireKeys, errors);
ReadUid(wire, path, allUids, errors);
foreach (var end in new[] { "from", "to" })
{
if (!wire.TryGetProperty(end, out var hole))
{
errors.Add($"{path}.{end}", "missing");
}
else
{
ValidateHoleRef(hole, $"{path}.{end}", boardUids, errors);
}
}
ReadColor(wire, "color", path, NamedColors, errors, required: false);
}
}
private static ParsedHole? ReadAnchor(JsonElement component, string path, HashSet<string> boardUids, ErrorList errors, bool required)
{
if (!component.TryGetProperty("anchor", out var anchor) || anchor.ValueKind == JsonValueKind.Null)
{
if (required)
{
errors.Add($"{path}.anchor", "missing");
}
return null;
}
return ValidateHoleRef(anchor, $"{path}.anchor", boardUids, errors);
}
private static ParsedHole? ValidateHoleRef(JsonElement hole, string path, HashSet<string> boardUids, ErrorList errors)
{
if (hole.ValueKind != JsonValueKind.Object)
{
errors.Add(path, "not_an_object");
return null;
}
ValidateBoardReference(hole, "board", path, boardUids, errors);
if (!hole.TryGetProperty("kind", out var kindElement))
{
errors.Add($"{path}.kind", "missing");
return null;
}
if (kindElement.ValueKind != JsonValueKind.String)
{
errors.Add($"{path}.kind", "not_a_string");
return null;
}
switch (kindElement.GetString())
{
case "main":
{
CheckKeys(hole, path, MainHoleKeys, errors);
var col = ReadInt(hole, "col", path, MainColumnMin, MainColumnMax, errors);
var row = ReadEnum(hole, "row", path, MainRows, errors, required: true);
return col is null || row is null ? null : new ParsedHole("main", col.Value, row);
}
case "rail":
{
CheckKeys(hole, path, RailHoleKeys, errors);
var rail = ReadEnum(hole, "rail", path, RailNames, errors, required: true);
var index = ReadInt(hole, "index", path, RailIndexMin, RailIndexMax, errors);
return rail is null || index is null ? null : new ParsedHole("rail", index.Value, rail);
}
default:
errors.Add($"{path}.kind", "unsupported");
return null;
}
}
private static bool TryGetArray(JsonElement circuit, string name, int maxLength, ErrorList errors, out JsonElement array)
{
array = default;
if (!circuit.TryGetProperty(name, out var element) || element.ValueKind == JsonValueKind.Null)
{
return false;
}
if (element.ValueKind != JsonValueKind.Array)
{
errors.Add(name, "not_an_array");
return false;
}
if (element.GetArrayLength() > maxLength)
{
errors.Add(name, "too_many");
return false;
}
array = element;
return true;
}
private static bool ReadProps(JsonElement component, string path, IReadOnlySet<string> allowed, ErrorList errors, bool required, out JsonElement props)
{
if (!component.TryGetProperty("props", out props) || props.ValueKind == JsonValueKind.Null)
{
if (required)
{
errors.Add($"{path}.props", "missing");
}
return false;
}
if (props.ValueKind != JsonValueKind.Object)
{
errors.Add($"{path}.props", "not_an_object");
return false;
}
CheckKeys(props, $"{path}.props", allowed, errors);
return true;
}
private static string? ReadUid(JsonElement element, string path, HashSet<string> allUids, ErrorList errors)
{
var uidPath = $"{path}.uid";
if (!element.TryGetProperty("uid", out var uidElement))
{
errors.Add(uidPath, "missing");
return null;
}
if (uidElement.ValueKind != JsonValueKind.String)
{
errors.Add(uidPath, "not_a_string");
return null;
}
var uid = uidElement.GetString()!;
if (uid.Length > MaxUidLength)
{
errors.Add(uidPath, "too_long");
return null;
}
if (!UidPattern.IsMatch(uid))
{
errors.Add(uidPath, "invalid_format");
return null;
}
if (!allUids.Add(uid))
{
errors.Add(uidPath, "duplicate");
return null;
}
return uid;
}
private static void ReadCoordinate(JsonElement element, string name, string path, ErrorList errors)
{
var coordinatePath = $"{path}.{name}";
if (!element.TryGetProperty(name, out var value))
{
errors.Add(coordinatePath, "missing");
return;
}
if (value.ValueKind != JsonValueKind.Number || !value.TryGetDouble(out var number) || !double.IsFinite(number))
{
errors.Add(coordinatePath, "not_a_number");
return;
}
if (Math.Abs(number) > MaxBoardCoordinate)
{
errors.Add(coordinatePath, "out_of_range");
}
}
private static int? ReadInt(JsonElement element, string name, string path, int min, int max, ErrorList errors)
{
var intPath = $"{path}.{name}";
if (!element.TryGetProperty(name, out var value))
{
errors.Add(intPath, "missing");
return null;
}
if (value.ValueKind != JsonValueKind.Number || !value.TryGetInt32(out var number))
{
errors.Add(intPath, "not_an_integer");
return null;
}
if (number < min || number > max)
{
errors.Add(intPath, "out_of_range");
return null;
}
return number;
}
private static string? ReadEnum(JsonElement element, string name, string path, IReadOnlySet<string> allowed, ErrorList errors, bool required)
{
var enumPath = $"{path}.{name}";
if (!element.TryGetProperty(name, out var value) || value.ValueKind == JsonValueKind.Null)
{
if (required)
{
errors.Add(enumPath, "missing");
}
return null;
}
if (value.ValueKind != JsonValueKind.String)
{
errors.Add(enumPath, "not_a_string");
return null;
}
var text = value.GetString()!;
if (text.Length > MaxStringLength || !allowed.Contains(text))
{
errors.Add(enumPath, "unsupported");
return null;
}
return text;
}
private static void ReadColor(JsonElement element, string name, string path, IReadOnlySet<string> namedColors, ErrorList errors, bool required)
{
var colorPath = $"{path}.{name}";
if (!element.TryGetProperty(name, out var value) || value.ValueKind == JsonValueKind.Null)
{
if (required)
{
errors.Add(colorPath, "missing");
}
return;
}
if (value.ValueKind != JsonValueKind.String)
{
errors.Add(colorPath, "not_a_string");
return;
}
var color = value.GetString()!;
if (color.Length > MaxStringLength || (!namedColors.Contains(color) && !HexColorPattern.IsMatch(color)))
{
errors.Add(colorPath, "unsupported");
}
}
/// <summary>Reads a board uid reference and confirms it names a board declared in this document.</summary>
private static string? ValidateBoardReference(JsonElement element, string name, string path, HashSet<string> boardUids, ErrorList errors)
{
var boardPath = $"{path}.{name}";
if (!element.TryGetProperty(name, out var board))
{
errors.Add(boardPath, "missing");
return null;
}
if (board.ValueKind != JsonValueKind.String)
{
errors.Add(boardPath, "not_a_string");
return null;
}
var uid = board.GetString()!;
if (uid.Length > MaxUidLength || !boardUids.Contains(uid))
{
errors.Add(boardPath, "unknown_board");
return null;
}
return uid;
}
/// <summary>
/// Rejects properties outside the schema and duplicate JSON keys (System.Text.Json
/// tolerates duplicates, which would otherwise let a document smuggle a second value
/// past whichever occurrence the reader picks).
/// </summary>
private static void CheckKeys(JsonElement element, string path, IReadOnlySet<string> allowed, ErrorList errors)
{
var seen = new HashSet<string>(StringComparer.Ordinal);
foreach (var property in element.EnumerateObject())
{
if (!allowed.Contains(property.Name))
{
errors.Add($"{path}.{SafeName(property.Name)}", "unknown_property");
}
else if (!seen.Add(property.Name))
{
errors.Add($"{path}.{property.Name}", "duplicate_property");
}
}
}
/// <summary>Unknown property names come from untrusted input, so only echo them when they are plainly safe.</summary>
private static string SafeName(string name) => SafeNamePattern.IsMatch(name) ? name : "?";
/// <summary>
/// A hole reference that passed validation. <paramref name="Position"/> is the column for
/// a main-grid hole and the tie-point index for a rail hole; <paramref name="Row"/> is the
/// row letter or the rail name respectively.
/// </summary>
private sealed record ParsedHole(string Kind, int Position, string Row);
private sealed class ErrorList
{
private readonly List<string> _errors = [];
private bool _truncated;
public bool HasErrors => _errors.Count > 0;
public void Add(string path, string reason)
{
if (_errors.Count >= MaxErrors)
{
_truncated = true;
return;
}
_errors.Add($"{path}:{reason}");
}
public IReadOnlyList<string> Build() => _truncated ? [.. _errors, "errors:truncated"] : _errors;
}
}