Class ScyllaSquareGrid<TCell>.SynchronizedScyllaSquareGrid

Thread-safe wrapper around ScyllaSquareGrid<TCell> that synchronizes every operation with a shared monitor lock.

Inheritance
object
ScyllaSquareGrid<TCell>.SynchronizedScyllaSquareGrid
Implements
Inherited Members
Namespace: Scylla.Core.Structures
Assembly: ScyllaCore.dll
Syntax
public sealed class ScyllaSquareGrid<TCell>.SynchronizedScyllaSquareGrid : IScyllaGrid<SquareCoord, TCell>, IScyllaCollection
Remarks

Obtain an instance via AsSynchronized(object) or Synchronized(object) followed by Build().

Each individual method call is atomic with respect to the shared lock. However, check-then-act sequences (e.g., read a value, then write it conditionally) are still subject to TOCTOU races unless the caller holds SyncRoot for the duration of the compound operation.

GridToWorld(SquareCoord) and WorldToGrid(Vector2) do not acquire the lock because they operate solely on the immutable cached SquareGridLayout.

Constructors

SynchronizedScyllaSquareGrid(ScyllaSquareGrid<TCell>, object)

Initializes a new synchronized wrapper around inner.

Declaration
public SynchronizedScyllaSquareGrid(ScyllaSquareGrid<TCell> inner, object syncRoot)
Parameters
Type Name Description
ScyllaSquareGrid<TCell> inner

The grid to wrap. Must not be null.
object syncRoot

The monitor object to use as the exclusive lock. When null, a new private object is created.
Exceptions
Type Condition
ArgumentNullException

Thrown when inner is null.

Properties

Capabilities

Gets the feature and capability flags supported by this collection instance.

Declaration
public ScyllaCollectionCapabilities Capabilities { get; }
Property Value
Type Description
ScyllaCollectionCapabilities

A bitfield of ScyllaCollectionCapabilities flags describing which optional operations the concrete instance supports. The value None indicates that only the base contract (Count, IsEmpty, Clear()) is available.
Remarks

Use Capabilities for feature detection in place of type-casting. For example: 

if ((collection.Capabilities & ScyllaCollectionCapabilities.SupportsPeek) != 0)
{
    // safe to call TryPeek through IScyllaCollection<T>
}

Synchronized wrappers cache the capability flags of their inner collection at construction time, so the value returned is stable and does not require synchronization.

See Also

CellCount

Gets the number of populated (logically active) cells in the grid.

Declaration
public int CellCount { get; }
Property Value
Type Description
int

For dense grids, this always equals Count - every cell slot is pre-allocated and considered populated regardless of its stored value. The value is fixed at construction and never changes.

For sparse grids, this equals the number of cells that have been explicitly written via TrySet(TCoord, TCell) and not yet removed. The value may be zero on a freshly created or cleared sparse grid.

See Also
TrySet(TCoord, TCell)

Count

Gets the number of items currently contained in the collection.

Declaration
public int Count { get; }
Property Value
Type Description
int

A non-negative integer representing the current element count. Returns 0 when the collection is empty.
Remarks

On unsynchronized collections, Count is not thread-safe and may return a stale value when accessed concurrently. On synchronized wrappers, reading Count is protected by the internal lock.

Height

Gets the number of rows in the wrapped grid.

Declaration
public int Height { get; }
Property Value
Type Description
int

IsEmpty

Always false. A dense grid pre-allocates every cell at construction and is never logically empty.

Declaration
public bool IsEmpty { get; }
Property Value
Type Description
bool

this[SquareCoord]

Gets or sets the cell value at the specified coordinate. The operation is performed under the shared lock.

Declaration
public TCell this[SquareCoord coord] { get; set; }
Parameters
Type Name Description
SquareCoord coord

The grid coordinate. Must be within the bounds of the wrapped grid.
Property Value
Type Description
TCell
Exceptions
Type Condition
IndexOutOfRangeException

Thrown when coord is out of bounds.

this[int, int]

Gets or sets the cell value at the specified column and row. The operation is performed under the shared lock.

Declaration
public TCell this[int col, int row] { get; set; }
Parameters
Type Name Description
int col

The zero-based column index. Must be in the range [0, Width).
int row

The zero-based row index. Must be in the range [0, Height).
Property Value
Type Description
TCell
Exceptions
Type Condition
IndexOutOfRangeException

Thrown when col or row is out of bounds.

SyncRoot

Gets the synchronization root object used to externally coordinate multi-step operations with this collection.

Declaration
public object SyncRoot { get; }
Property Value
Type Description
object

A non-null object suitable for use with lock when ThreadSafety is Synchronized. Returns null for unsynchronized collections, which do not own a lock.
Remarks

When this collection is a synchronized wrapper, SyncRoot must be non-null and stable for the entire lifetime of the wrapper. All internal operations on the wrapper must lock on this same object. This allows callers to perform atomic multi-step sequences: 

lock (collection.SyncRoot)
{
    if (!collection.IsEmpty)
        typedCollection.TryRemove(out var item);
}

For unsynchronized collections (SyncRoot == null), callers are responsible for supplying and consistently applying their own external synchronization mechanism. A null SyncRoot does not mean the collection is thread-safe; consult ThreadSafety for the authoritative guarantee.

See Also

ThreadSafety

Gets the thread-safety guarantees provided by this collection instance.

Declaration
public ScyllaCollectionThreadSafety ThreadSafety { get; }
Property Value
Type Description
ScyllaCollectionThreadSafety

A ScyllaCollectionThreadSafety value indicating whether the collection is unsynchronized, synchronized via a lock, or safe for lock-free concurrent access. Most core implementations return Unsynchronized. Synchronized wrappers return Synchronized.
Remarks

Always check this property (or SyncRoot) before assuming a collection is safe for concurrent use. Do not rely solely on the absence of a non-null SyncRoot to infer thread safety; use this property as the authoritative source.

See Also

Width

Gets the number of columns in the wrapped grid.

Declaration
public int Width { get; }
Property Value
Type Description
int

Methods

Clear()

Removes all items from the collection and resets it to an empty state.

Declaration
public void Clear()
Remarks

Implementations that store reference-type elements should null out internal slots after clearing to avoid retaining object references and preventing garbage collection. After Clear returns, Count must be 0 and IsEmpty must be true.

On synchronized wrappers this operation is protected by the collection's internal lock. On unsynchronized collections, callers are responsible for external coordination.

Contains(SquareCoord)

Determines whether the specified coordinate is addressable and populated in this grid.

Declaration
public bool Contains(SquareCoord coord)
Parameters
Type Name Description
SquareCoord coord

The coordinate to test.
Returns
Type Description
bool

For dense grids, returns true when coord maps to a valid index within the grid's pre-allocated array - that is, when the coordinate is geometrically within the grid's dimensions, regardless of the stored value.

For sparse grids, returns true only when coord has been explicitly written via TrySet(TCoord, TCell) and not since removed. An in-bounds coordinate that has never been written returns false.

Remarks

This method is equivalent to checking whether TryGet(TCoord, out TCell) would return true for the same coordinate. Use it when you only need the existence check and do not need the value.

See Also
TryGet(TCoord, out TCell)
TrySet(TCoord, TCell)

Fill(TCell)

Fills every cell in the wrapped grid with value. The operation is performed under the shared lock.

Declaration
public void Fill(TCell value)
Parameters
Type Name Description
TCell value

The value to write into every cell.

GetNeighborsNonAlloc(SquareCoord, Span<SquareCoord>, SquareAdjacency)

Writes the in-bounds neighbors of coord into buffer. The operation is performed under the shared lock.

Declaration
public int GetNeighborsNonAlloc(SquareCoord coord, Span<SquareCoord> buffer, SquareAdjacency adjacency = SquareAdjacency.VonNeumann)
Parameters
Type Name Description
SquareCoord coord

The cell whose neighbors are requested.
Span<SquareCoord> buffer

A span to receive the neighbor coordinates.
SquareAdjacency adjacency

The adjacency model to use. Defaults to VonNeumann.
Returns
Type Description
int

The number of neighbors written into buffer.

GridToWorld(SquareCoord)

Converts a grid coordinate to world-space position. Does not acquire the lock; operates on the immutable cached layout.

Declaration
public Vector2 GridToWorld(SquareCoord coord)
Parameters
Type Name Description
SquareCoord coord

The grid coordinate to convert.
Returns
Type Description
Vector2

The world-space UnityEngine.Vector2 at the center of the cell.

IsInBounds(int, int)

Determines whether the specified column and row fall within the wrapped grid's bounds. This check does not acquire the lock because the dimensions are cached and immutable.

Declaration
public bool IsInBounds(int col, int row)
Parameters
Type Name Description
int col

The column index to test.
int row

The row index to test.
Returns
Type Description
bool

true if both indices are within [0, Width) and [0, Height); false otherwise.

TryGet(SquareCoord, out TCell)

Attempts to retrieve the value stored at the specified coordinate without throwing on failure.

Declaration
public bool TryGet(SquareCoord coord, out TCell value)
Parameters
Type Name Description
SquareCoord coord

The grid coordinate to look up.
TCell value

When this method returns true, contains the cell value at coord. When this method returns false, contains default(TCell). This parameter is passed uninitialized and is always written before this method returns.
Returns
Type Description
bool

true if coord is within the grid's valid range and a value was successfully read; false if the coordinate is out of bounds (dense grids) or has not been explicitly written (sparse grids).
Remarks

Prefer this method over direct indexer access when the coordinate's validity is not guaranteed, as it avoids the cost of exception handling on out-of-bounds access. For dense grids, "within bounds" means the coordinate maps to a valid flat-array index. For sparse grids, "within bounds" additionally requires that the cell has been set.

See Also
TrySet(TCoord, TCell)
Contains(TCoord)

TrySet(SquareCoord, TCell)

Attempts to store a value at the specified coordinate without throwing on failure.

Declaration
public bool TrySet(SquareCoord coord, TCell value)
Parameters
Type Name Description
SquareCoord coord

The grid coordinate to write to.
TCell value

The value to store at coord.
Returns
Type Description
bool

true if the coordinate is valid and the value was successfully stored; false if the coordinate is out of bounds and no change was made.
Remarks

For dense grids, this writes to the pre-allocated cell at coord and returns false if the coordinate falls outside the grid's dimensions.

For sparse grids, this inserts or updates the entry at coord and returns false only when the grid is bounded and coord falls outside the defined bounds. On unbounded sparse grids this method always returns true.

A successful call increments CellCount on sparse grids when coord is newly written for the first time.

See Also
TryGet(TCoord, out TCell)
Contains(TCoord)

WorldToGrid(Vector2)

Converts a world-space position to a grid coordinate. Does not acquire the lock; operates on the immutable cached layout.

Declaration
public SquareCoord WorldToGrid(Vector2 worldPos)
Parameters
Type Name Description
Vector2 worldPos

The world-space position to convert.
Returns
Type Description
SquareCoord

The grid coordinate of the cell containing worldPos.

Implements

Extension Methods