Add primitive code gen support for .NET Core

Author: AArnott

src/Nerdbank.GitVersioning.Tasks/AssemblyVersionInfo.cs

@@ -1,6 +1,6 @@
 namespace Nerdbank.GitVersioning.Tasks
 {
-    using System;   
+    using System;
     using System.CodeDom;
     using System.CodeDom.Compiler;
     using System.Collections.Generic;
@@ -24,6 +24,21 @@ public class AssemblyVersionInfo : Task
         };
 
         private CodeCompileUnit generatedFile;
+#else
+        private const string FileHeaderComment = @"------------------------------------------------------------------------------
+ <auto-generated>
+     This code was generated by a tool.
+     Runtime Version:4.0.30319.42000
+
+     Changes to this file may cause incorrect behavior and will be lost if
+     the code is regenerated.
+ </auto-generated>
+------------------------------------------------------------------------------
+";
+
+        private CodeGenerator generator;
+
+#endif
 
         [Required]
         public string CodeLanguage { get; set; }
@@ -55,6 +70,7 @@ public class AssemblyVersionInfo : Task
 
         public string AssemblyConfiguration { get; set; }
 
+#if NET45
         public override bool Execute()
         {
             if (CodeDomProvider.IsDefinedLanguage(this.CodeLanguage))
@@ -127,7 +143,7 @@ private CodeTypeDeclaration CreateThisAssemblyClass()
             return thisAssembly;
         }
 
-        private void ReadKeyInfo(out string publicKey, out string publicKeyToken)
+       private void ReadKeyInfo(out string publicKey, out string publicKeyToken)
         {
             byte[] publicKeyBytes = null;
             if (!string.IsNullOrEmpty(this.AssemblyOriginatorKeyFile) && File.Exists(this.AssemblyOriginatorKeyFile))
@@ -213,11 +229,156 @@ private static CodeAttributeDeclaration DeclareAttribute(Type attributeType, par
                 attributeType,
                 arguments.Select(a => new CodeAttributeArgument(new CodePrimitiveExpression(a))).ToArray());
         }
+
 #else
+
         public override bool Execute()
         {
-            this.Log.LogError("Not yet implemented.");
-            return false;
+            this.generator = this.CreateGenerator();
+            if (this.generator != null)
+            {
+                this.generator.AddComment(FileHeaderComment);
+                this.generator.AddBlankLine();
+                this.CreateAssemblyAttributes();
+                this.CreateThisAssemblyClass();
+
+                Directory.CreateDirectory(Path.GetDirectoryName(this.OutputFile));
+                File.WriteAllText(this.OutputFile, this.generator.GetCode());
+            }
+
+            return !this.Log.HasLoggedErrors;
+        }
+
+        private void CreateAssemblyAttributes()
+        {
+            this.generator.DeclareAttribute(typeof(AssemblyVersionAttribute), this.AssemblyVersion);
+            this.generator.DeclareAttribute(typeof(AssemblyFileVersionAttribute), this.AssemblyFileVersion);
+            this.generator.DeclareAttribute(typeof(AssemblyInformationalVersionAttribute), this.AssemblyInformationalVersion);
+            if (!string.IsNullOrEmpty(this.AssemblyTitle))
+                this.generator.DeclareAttribute(typeof(AssemblyTitleAttribute), this.AssemblyTitle);
+            if (!string.IsNullOrEmpty(this.AssemblyProduct))
+                this.generator.DeclareAttribute(typeof(AssemblyProductAttribute), this.AssemblyProduct);
+            if (!string.IsNullOrEmpty(this.AssemblyCompany))
+                this.generator.DeclareAttribute(typeof(AssemblyCompanyAttribute), this.AssemblyCompany);
+            if (!string.IsNullOrEmpty(this.AssemblyCopyright))
+                this.generator.DeclareAttribute(typeof(AssemblyCopyrightAttribute), this.AssemblyCopyright);
+        }
+
+        private void CreateThisAssemblyClass()
+        {
+            this.generator.StartThisAssemblyClass();
+
+            ////// Determine information about the public key used in the assembly name.
+            ////string publicKey, publicKeyToken;
+            ////this.ReadKeyInfo(out publicKey, out publicKeyToken);
+
+            // Define the constants.
+            var fields = new Dictionary<string, string>
+                {
+                    { "AssemblyVersion", this.AssemblyVersion },
+                    { "AssemblyFileVersion", this.AssemblyFileVersion },
+                    { "AssemblyInformationalVersion", this.AssemblyInformationalVersion },
+                    { "AssemblyName", this.AssemblyName },
+                    ////{ "PublicKey", publicKey },
+                    ////{ "PublicKeyToken", publicKeyToken },
+                    { "AssemblyTitle", this.AssemblyTitle },
+                    { "AssemblyProduct", this.AssemblyProduct },
+                    { "AssemblyCopyright", this.AssemblyCopyright },
+                    { "AssemblyCompany", this.AssemblyCompany },
+                    { "AssemblyConfiguration", this.AssemblyConfiguration }
+                };
+            foreach (var pair in fields)
+            {
+                if (!string.IsNullOrEmpty(pair.Value))
+                {
+                    this.generator.AddThisAssemblyMember(pair.Key, pair.Value);
+                }
+            }
+
+            // These properties should be defined even if they are empty.
+            this.generator.AddThisAssemblyMember("RootNamespace", this.RootNamespace);
+
+            this.generator.EndThisAssemblyClass();
+        }
+        private CodeGenerator CreateGenerator()
+        {
+            switch (this.CodeLanguage.ToLowerInvariant())
+            {
+                case "c#":
+                    return new CSharpCodeGenerator();
+                case "visual basic":
+                case "visualbasic":
+                case "vb":
+                default:
+                    this.Log.LogError("Code provider not available for language: {0}. No version info will be embedded into assembly.", this.CodeLanguage);
+                    return null;
+            }
+        }
+
+        private abstract class CodeGenerator
+        {
+            protected readonly StringBuilder codeBuilder;
+
+            internal CodeGenerator()
+            {
+                this.codeBuilder = new StringBuilder();
+            }
+
+            internal abstract void AddComment(string comment);
+
+            internal abstract void DeclareAttribute(Type type, string arg);
+
+            internal abstract void StartThisAssemblyClass();
+
+            internal abstract void AddThisAssemblyMember(string name, string value);
+
+            internal abstract void EndThisAssemblyClass();
+
+            internal string GetCode() => this.codeBuilder.ToString();
+
+            internal void AddBlankLine()
+            {
+                this.codeBuilder.AppendLine();
+            }
+
+            protected void AddCodeComment(string comment, string token)
+            {
+                var sr = new StringReader(comment);
+                string line;
+                while ((line = sr.ReadLine()) != null)
+                {
+                    this.codeBuilder.Append(token);
+                    this.codeBuilder.AppendLine(line);
+                }
+            }
+        }
+
+        private class CSharpCodeGenerator : CodeGenerator
+        {
+            internal override void AddComment(string comment)
+            {
+                this.AddCodeComment(comment, "//");
+            }
+
+            internal override void DeclareAttribute(Type type, string arg)
+            {
+                this.codeBuilder.AppendLine($"[assembly: {type.FullName}(\"{arg}\")]");
+            }
+
+            internal override void StartThisAssemblyClass()
+            {
+                this.codeBuilder.AppendLine("internal static partial class ThisAssembly {");
+            }
+
+            internal override void AddThisAssemblyMember(string name, string value)
+            {
+                this.codeBuilder.AppendLine($"    internal const string {name} = \"{value}\";");
+            }
+
+            internal override void EndThisAssemblyClass()
+            {
+                this.codeBuilder.AppendLine("}");
+            }
         }
 #endif
     }