Migrate GenerateFileFromTemplate to Microsoft.DotNet.Build.Tasks.Templating

src/Microsoft.DotNet.Build.Tasks.Templating/GenerateFileFromTemplate.cs

@@ -0,0 +1,147 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+
+namespace Microsoft.DotNet.Build.Tasks.Templating
+{
+    /// <summary>
+    /// <para>
+    /// Generates a new file at <see cref="OutputPath"/>.
+    /// </para>
+    /// <para>
+    /// The <see cref="TemplateFile"/> can define variables for substitution using <see cref="Properties"/>.
+    /// </para>
+    /// <example>
+    /// The input file might look like this:
+    /// <code>
+    /// 2 + 2 = ${Sum}
+    /// </code>
+    /// When the task is invoked like this, it will produce "2 + 2 = 4"
+    /// <code>
+    /// &lt;GenerateFileFromTemplate Properties="Sum=4;OtherValue=123;" ... &gt;
+    /// </code>
+    /// </example>
+    /// </summary>
+    public class GenerateFileFromTemplate : Task
+    {
+        /// <summary>
+        /// The template file using the variable syntax <c>${VarName}</c>.
+        /// If your template file needs to output this format, you can escape the dollar sign with a backtick e.g. <c>`${NotReplaced}</c>.
+        /// </summary>
+        [Required]
+        public string TemplateFile { get; set; }
+
+        /// <summary>
+        /// The destination for the generated file.
+        /// </summary>
+        [Required]
+        [Output]
+        public string OutputPath { get; set; }
+
+        /// <summary>
+        /// Key=Value pairs of values, separated by semicolons e.g. <c>Properties="Sum=4;OtherValue=123;"</c>.
+        /// </summary>
+        [Required]
+        public string[] Properties { get; set; }
+
+        public override bool Execute()
+        {
+            string outputPath = Path.GetFullPath(OutputPath.Replace('\\', '/'));
+
+            if (!File.Exists(TemplateFile))
+            {
+                Log.LogError($"File {TemplateFile} does not exist");
+                return false;
+            }
+
+            IDictionary<string, string> values = MSBuildListSplitter.GetNamedProperties(Properties, Log);
+            string template = File.ReadAllText(TemplateFile);
+
+            string result = Replace(template, values);
+            Directory.CreateDirectory(Path.GetDirectoryName(outputPath));
+            File.WriteAllText(outputPath, result);
+
+            return !Log.HasLoggedErrors;
+        }
+
+        public string Replace(string template, IDictionary<string, string> values)
+        {
+            StringBuilder sb = new();
+            StringBuilder varNameSb = new();
+            int line = 1;
+            for (int i = 0; i < template.Length; i++)
+            {
+                char templateChar = template[i];
+                char nextTemplateChar = i + 1 >= template.Length
+                        ? '\0'
+                        : template[i + 1];
+
+                // count lines in the template file
+                if (templateChar == '\n')
+                {
+                    line++;
+                }
+
+                if (templateChar == '`' && (nextTemplateChar == '$' || nextTemplateChar == '`'))
+                {
+                    // skip the backtick for known escape characters
+                    i++;
+                    sb.Append(nextTemplateChar);
+                    continue;
+                }
+
+                if (templateChar != '$' || nextTemplateChar != '{')
+                {
+                    // variables begin with ${. Moving on.
+                    sb.Append(templateChar);
+                    continue;
+                }
+
+                varNameSb.Clear();
+                i += 2;
+                for (; i < template.Length; i++)
+                {
+                    templateChar = template[i];
+                    if (templateChar != '}')
+                    {
+                        varNameSb.Append(templateChar);
+                    }
+                    else
+                    {
+                        // Found the end of the variable substitution
+                        string varName = varNameSb.ToString();
+                        if (values.TryGetValue(varName, out string value))
+                        {
+                            sb.Append(value);
+                        }
+                        else
+                        {
+                            Log.LogWarning(null, null, null, TemplateFile,
+                                line, 0, 0, 0,
+                                message: $"No property value is available for '{varName}'");
+                        }
+
+                        varNameSb.Clear();
+                        break;
+                    }
+                }
+
+                if (varNameSb.Length > 0)
+                {
+                    Log.LogWarning(null, null, null, TemplateFile,
+                                line, 0, 0, 0,
+                                message: "Expected closing bracket for variable placeholder. No substitution will be made.");
+                    sb.Append("${").Append(varNameSb.ToString());
+                }
+            }
+
+            return sb.ToString();
+        }
+    }
+}
+

src/Microsoft.DotNet.Build.Tasks.Templating/MSBuildListSplitter.cs

@@ -0,0 +1,43 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Build.Utilities;
+
+namespace Microsoft.DotNet.Build.Tasks.Templating
+{
+    internal static class MSBuildListSplitter
+    {
+        public static IDictionary<string, string> GetNamedProperties(string[] input, TaskLoggingHelper log)
+        {
+            Dictionary<string, string> values = new(StringComparer.OrdinalIgnoreCase);
+            if (input == null)
+            {
+                return values;
+            }
+
+            foreach (string item in input)
+            {
+                int splitIdx = item.IndexOf('=');
+                if (splitIdx < 0)
+                {
+                    log.LogWarning($"Property: {item} does not have a valid '=' separator");
+                    continue;
+                }
+
+                string key = item.Substring(0, splitIdx).Trim();
+                if (string.IsNullOrEmpty(key))
+                {
+                    log.LogWarning($"Property: {item} does not have a valid property name");
+                    continue;
+                }
+
+                string value = item.Substring(splitIdx + 1);
+                values[key] = value;
+            }
+
+            return values;
+        }
+    }
+}

src/Microsoft.DotNet.Build.Tasks.Templating/Microsoft.DotNet.Build.Tasks.Templating.csproj

@@ -0,0 +1,29 @@
+<!-- Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. -->
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.0</TargetFramework>
+    <Description>Templating task package</Description>
+    <PackageTags>Arcade Build Tool Templating</PackageTags>
+    <IncludeSymbols>false</IncludeSymbols>
+    <IncludeSource>false</IncludeSource>
+    <IsPackable>true</IsPackable>
+    <BuildOutputTargetFolder>tools\</BuildOutputTargetFolder>
+    <DevelopmentDependency>true</DevelopmentDependency>
+    <SuppressDependenciesWhenPacking>true</SuppressDependenciesWhenPacking>
+    <EnableDefaultNoneItems>false</EnableDefaultNoneItems>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include="build/**/*.*" Pack="true">
+      <PackagePath>build</PackagePath>
+    </None>
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Build.Framework" Version="$(MicrosoftBuildFrameworkVersion)" />
+    <PackageReference Include="Microsoft.Build.Utilities.Core" Version="$(MicrosoftBuildUtilitiesCoreVersion)" />
+  </ItemGroup>
+
+  <Import Project="$(RepoRoot)eng\BuildTask.targets" />
+</Project>

src/Microsoft.DotNet.Build.Tasks.Templating/build/Microsoft.DotNet.Build.Tasks.Templating.props

@@ -0,0 +1,10 @@
+<!-- Licensed to the .NET Foundation under one or more agreements. The .NET Foundation licenses this file to you under the MIT license. -->
+<Project>
+
+  <PropertyGroup>
+    <MicrosoftDotNetBuildTasksTemplatingAssembly>$(MSBuildThisFileDirectory)..\tools\netstandard2.0\Microsoft.DotNet.Build.Tasks.Templating.dll</MicrosoftDotNetBuildTasksTemplatingAssembly>
+  </PropertyGroup>
+
+  <UsingTask TaskName="Microsoft.DotNet.Build.Tasks.Templating.GenerateFileFromTemplate" AssemblyFile="$(MicrosoftDotNetBuildTasksTemplatingAssembly)" />
+
+</Project>