Implement embedded resource decompressor

OfficeFlow.Word.OpenXml.Tests/OfficeFlow.Word.OpenXml.Tests.csproj

@@ -7,6 +7,7 @@
     </PropertyGroup>
 
     <ItemGroup>
+        <PackageReference Include="FluentAssertions" />
         <PackageReference Include="Microsoft.NET.Test.Sdk" />
         <PackageReference Include="xunit" />
         <PackageReference Include="xunit.runner.visualstudio">
@@ -19,4 +20,12 @@
         </PackageReference>
     </ItemGroup>
 
+    <ItemGroup>
+        <EmbeddedResource Include="Resources\Embedded\TestEmbeddedResource.xml.gz" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\OfficeFlow.Word.OpenXml\OfficeFlow.Word.OpenXml.csproj" />
+    </ItemGroup>
+
 </Project>

OfficeFlow.Word.OpenXml.Tests/Resources/Embedded/EmbeddedResourceDecompressorTests.cs

@@ -0,0 +1,44 @@
+using System.Xml.Linq;
+using FluentAssertions;
+using OfficeFlow.Word.OpenXml.Resources.Embedded;
+using OfficeFlow.Word.OpenXml.Resources.Exceptions;
+using Xunit;
+
+namespace OfficeFlow.Word.OpenXml.Tests.Resources.Embedded
+{
+    public sealed class EmbeddedResourceDecompressorTests
+    {
+        [Fact]
+        public void Should_decompress_exists_embedded_resource_from_calling_assembly()
+        {
+            // Arrange
+            var expectedXml = new XElement
+            (
+                "document",
+                new XElement
+                (
+                    "body", 
+                    new XText("Content")
+                )
+            );
+
+            var sut = new EmbeddedResourceDecompressor();
+
+            // Act
+            var actualXml = sut.Decompress("TestEmbeddedResource.xml.gz");
+
+            // Assert
+            actualXml
+                .Root
+                .Should()
+                .BeEquivalentTo(expectedXml);
+        }
+
+        [Fact]
+        public void Should_throws_exception_if_resource_not_found_in_calling_assembly()
+            => new EmbeddedResourceDecompressor()
+                .Invoking(decompressor => decompressor.Decompress("NotExistsResource.xml.gz"))
+                .Should()
+                .Throw<ResourceNotFoundException>();
+    }
+}

OfficeFlow.Word.OpenXml/OfficeFlow.Word.OpenXml.csproj

@@ -6,7 +6,16 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <Folder Include="Packaging\" />
+        <PackageReference Include="System.IO.Packaging" />
     </ItemGroup>
 
+    <ItemGroup>
+        <EmbeddedResource Include="Resources\Embedded\Default\bulletNumbering.xml.gz" />
+        <EmbeddedResource Include="Resources\Embedded\Default\decimalNumbering.xml.gz" />
+        <EmbeddedResource Include="Resources\Embedded\Default\numbering.xml.gz" />
+        <EmbeddedResource Include="Resources\Embedded\Default\styles.xml.gz" />
+        <EmbeddedResource Include="Resources\Embedded\Default\wordDocument.xml.gz" />
+        <EmbeddedResource Include="Resources\Embedded\Default\wordStyles.xml.gz" />
+    </ItemGroup>
+
 </Project>

OfficeFlow.Word.OpenXml/Resources/Embedded/EmbeddedResourceDecompressor.cs

@@ -0,0 +1,49 @@
+using System;
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using System.Reflection;
+using System.Xml.Linq;
+using OfficeFlow.Word.OpenXml.Resources.Exceptions;
+using OfficeFlow.Word.OpenXml.Resources.Interfaces;
+
+namespace OfficeFlow.Word.OpenXml.Resources.Embedded
+{
+    public sealed class EmbeddedResourceDecompressor : IResourceDecompressor
+    {
+        private readonly Assembly _assembly;
+
+        private static readonly Lazy<EmbeddedResourceDecompressor> InstanceFactory = 
+            new Lazy<EmbeddedResourceDecompressor>(() => new EmbeddedResourceDecompressor());
+
+        public static EmbeddedResourceDecompressor Instance 
+            => InstanceFactory.Value;
+
+        public EmbeddedResourceDecompressor()
+            : this(Assembly.GetCallingAssembly())
+        { }
+
+        public EmbeddedResourceDecompressor(Assembly assembly)
+            => _assembly = assembly;
+
+        private Stream GetResourceStream(string resourceName)
+        {
+            var resourcePath = _assembly
+                .GetManifestResourceNames()
+                .FirstOrDefault(name => name.EndsWith(resourceName))    
+                    ?? throw new ResourceNotFoundException(resourceName);
+
+            return _assembly.GetManifestResourceStream(resourcePath)
+                ?? throw new ResourceNotLoadedException(resourceName);
+        }
+
+        public XDocument Decompress(string resourceName)
+        {
+            var stream = GetResourceStream(resourceName);
+            using var zip = new GZipStream(stream, CompressionMode.Decompress);
+            using var reader = new StreamReader(zip);
+
+            return XDocument.Load(reader);
+        }
+    }
+}

OfficeFlow.Word.OpenXml/Resources/Exceptions/ResourceNotFoundException.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace OfficeFlow.Word.OpenXml.Resources.Exceptions
+{
+    public sealed class ResourceNotFoundException : Exception
+    {
+        public ResourceNotFoundException(string resourceName, Exception? innerException = null)
+            : base($"Resource \"{resourceName}\" not found", innerException)
+        { }
+    }
+}

OfficeFlow.Word.OpenXml/Resources/Exceptions/ResourceNotLoadedException.cs

@@ -0,0 +1,11 @@
+using System;
+
+namespace OfficeFlow.Word.OpenXml.Resources.Exceptions
+{
+    public sealed class ResourceNotLoadedException : Exception
+    {
+        public ResourceNotLoadedException(string resourceName, Exception? innerException = null)
+            : base($"Failed to load resource \"{resourceName}\"", innerException)
+        { }
+    }
+}

OfficeFlow.Word.OpenXml/Resources/Interfaces/IResourceDecompressor.cs

@@ -0,0 +1,9 @@
+using System.Xml.Linq;
+
+namespace OfficeFlow.Word.OpenXml.Resources.Interfaces
+{
+    public interface IResourceDecompressor
+    {
+        XDocument Decompress(string resourceName);
+    }
+}