Streamline image loading by using NSData for interop of the image bytes. (#18)

* Streamline image loading by using NSData for interop of the image bytes.
* Add trailing newlines.
* Fix some spacing issues called out in code review.
* Handle nil in Texture2D.CreateFromNSDataPtr()
* More spacing fixes.

Author: AdamSzApple

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Runtime/NSData.cs

@@ -0,0 +1,51 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Apple.Core.Runtime
+{
+    /// <summary>
+    /// C# wrapper around NSData.
+    /// </summary>
+    public class NSData : NSObject
+    {
+        /// <summary>
+        /// Construct an NSData wrapper around an existing instance.
+        /// </summary>
+        /// <param name="pointer"></param>
+        public NSData(IntPtr pointer) : base(pointer)
+        {
+        }
+
+        /// <summary>
+        /// The number of bytes contained by the data object.
+        /// </summary>
+        public UInt64 Length => Interop.NSData_GetLength(Pointer, NSException.ThrowOnExceptionCallback);
+
+        /// <summary>
+        /// Return the object's contents as a byte array.
+        /// </summary>
+        public byte[] Bytes
+        {
+            get
+            {
+                byte[] bytes = null;
+
+                var length = (int)Length;
+                var bytePtr = Interop.NSData_GetBytes(Pointer, NSException.ThrowOnExceptionCallback);
+                if (length >= 0 && bytePtr != IntPtr.Zero)
+                {
+                    bytes = new byte[length];
+                    Marshal.Copy(bytePtr, bytes, 0, length);
+                }
+
+                return bytes;
+            }
+        }
+
+        private static class Interop
+        {
+            [DllImport(InteropUtility.DLLName)] public static extern UInt64 NSData_GetLength(IntPtr nsDataPtr, NSExceptionCallback onException);
+            [DllImport(InteropUtility.DLLName)] public static extern IntPtr NSData_GetBytes(IntPtr nsDataPtr, NSExceptionCallback onException);
+        }
+    }
+}

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Runtime/NSData.cs.meta

@@ -25,7 +25,7 @@ public NSString() : this(Interop.NSString_string()) { }
         /// Construct an NSString around a C# string.
         /// </summary>
         /// <param name="s"></param>
-        public NSString(string s) : this(Interop.NSString_StringWithUTF8String(s)) { }
+        public NSString(string s) : this(Interop.NSString_StringWithUtf8String(s)) { }
 
         private static readonly NSString _empty = new NSString();
         public static NSString Empty => _empty;
@@ -43,11 +43,25 @@ public NSString(string s) : this(Interop.NSString_StringWithUTF8String(s)) { }
         /// <param name="s"></param>
         public static implicit operator NSString(string s) => new NSString(s);
 
+        /// <summary>
+        /// Construct an NSString from UTF8 formatted NSData.
+        /// </summary>
+        /// <param name="data"></param>
+        public NSString(NSData data) : this(Interop.NSString_StringWithUtf8Data(data.Pointer)) { }
+
+        /// <summary>
+        /// Convert a C# string to UTF8 formatted NSData.
+        /// </summary>
+        public NSData Utf8Data => PointerCast<NSData>(Interop.NSString_Utf8Data(Pointer));
+        public static explicit operator NSData(NSString s) => s.Utf8Data;
+
         private static class Interop
         {
             [DllImport(InteropUtility.DLLName)] public static extern IntPtr NSString_string();
-            [DllImport(InteropUtility.DLLName)] public static extern IntPtr NSString_StringWithUTF8String(string s);
+            [DllImport(InteropUtility.DLLName)] public static extern IntPtr NSString_StringWithUtf8String(string s);
             [DllImport(InteropUtility.DLLName)] public static extern string NSString_Utf8String(IntPtr nsStringPtr);
+            [DllImport(InteropUtility.DLLName)] public static extern IntPtr NSString_StringWithUtf8Data(IntPtr nsDataPtr);
+            [DllImport(InteropUtility.DLLName)] public static extern IntPtr NSString_Utf8Data(IntPtr nsStringPtr);
         }
     }
 }

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Runtime/NSString.cs

@@ -0,0 +1,36 @@
+using System;
+using UnityEngine;
+
+namespace Apple.Core.Runtime
+{
+    public static class Texture2DExtensions
+    {
+        /// <summary>
+        /// Create a Texture2D object from the contents of an NSData object.
+        /// </summary>
+        /// <param name="nsData"></param>
+        /// <returns>The created texture if successful; null otherwise.</returns>
+        public static Texture2D CreateFromNSData(NSData nsData)
+        {
+            Texture2D texture = null;
+
+            if (nsData?.Length > 0)
+            {
+                texture = new Texture2D(1, 1);
+                texture.LoadImage(nsData.Bytes);
+            }
+
+            return texture;
+        }
+
+        /// <summary>
+        /// Create a Texture2D object from the contents of an NSData object referenced via IntPtr.
+        /// </summary>
+        /// <param name="nsDataPtr"></param>
+        /// <returns>The created texture if successful; null otherwise.</returns>
+        public static Texture2D CreateFromNSDataPtr(IntPtr nsDataPtr)
+        {
+            return (nsDataPtr != IntPtr.Zero) ? CreateFromNSData(InteropReference.PointerCast<NSData>(nsDataPtr)) : null;
+        }
+    }
+}

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Runtime/Texture2DExtensions.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+
+using Apple.Core.Runtime;
+using System;
+
+public class TestNSData
+{
+    [Test]
+    public void TestBasicOperations()
+    {
+        NSData emptyData = NSString.Empty.Utf8Data;
+        Assert.AreEqual(emptyData.Length, 0);
+
+        NSString emptyString = new NSString(emptyData);
+        Assert.AreEqual(string.Empty, emptyString.ToString());
+
+        NSData testData = new NSString("test").Utf8Data;
+        Assert.AreEqual(testData.Length, 4);
+        
+        NSString testString = new NSString(testData);
+        Assert.AreEqual("test", testString.ToString());
+    }
+}

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Runtime/Texture2DExtensions.cs.meta

@@ -1,5 +1,6 @@
 <linker>
     <assembly fullname="Apple.Core" preserve="all"/>
+    <assembly fullname="Apple.Core.Runtime" preserve="all"/>
     <assembly fullname="System.Collections" preserve="all"/>
     <assembly fullname="System.Collections.Generic" preserve="all"/>
     <assembly fullname="System.Reflection" preserve="all"/>

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Tests/Runtime/TestNSData.cs

@@ -3,7 +3,7 @@
     "com.unity.2d.sprite": "1.0.0",
     "com.unity.2d.tilemap": "1.0.0",
     "com.unity.ai.navigation": "1.1.5",
-    "com.unity.ide.rider": "3.0.26",
+    "com.unity.ide.rider": "3.0.27",
     "com.unity.ide.visualstudio": "2.0.22",
     "com.unity.ide.vscode": "1.2.5",
     "com.unity.test-framework": "1.1.33",

plug-ins/Apple.Core/Apple.Core_Unity/Assets/Apple.Core/Tests/Runtime/TestNSData.cs.meta

@@ -32,7 +32,7 @@
       "url": "https://packages.unity.com"
     },
     "com.unity.ide.rider": {
-      "version": "3.0.26",
+      "version": "3.0.27",
       "depth": 0,
       "source": "registry",
       "dependencies": {