Add RazorProject - an abstraction for working with Razor files in a project

Fixes #842

src/Microsoft.AspNetCore.Razor.Evolution/RazorProject.cs

@@ -0,0 +1,20 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+
+namespace Microsoft.AspNetCore.Razor.Evolution
+{
+    /// <summary>
+    /// An abstraction for working with a project containing Razor files.
+    /// </summary>
+    public abstract class RazorProject
+    {
+        /// <summary>
+        /// Gets a sequence of <see cref="RazorProjectItem"/> under the specific path in the project.
+        /// </summary>
+        /// <param name="basePath">The base path.</param>
+        /// <returns>The sequence of <see cref="RazorProjectItem"/>.</returns>
+        public abstract IEnumerable<RazorProjectItem> EnumerateItems(string basePath);
+    }
+}

src/Microsoft.AspNetCore.Razor.Evolution/RazorProjectItem.cs

@@ -0,0 +1,104 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Diagnostics;
+using System.IO;
+
+namespace Microsoft.AspNetCore.Razor.Evolution
+{
+    /// <summary>
+    /// An item in <see cref="RazorProject"/>.
+    /// </summary>
+    [DebuggerDisplay("{CombinedPath}")]
+    public abstract class RazorProjectItem
+    {
+        /// <summary>
+        /// Path specified in <see cref="RazorProject.EnumerateItems(string)"/>.
+        /// </summary>
+        public abstract string BasePath { get; }
+
+        /// <summary>
+        /// Path relative to <see cref="BasePath"/>.
+        /// </summary>
+        public abstract string Path { get; }
+
+        /// <summary>
+        /// The absolute path to the file, including the file name.
+        /// </summary>
+        public abstract string PhysicalPath { get; }
+
+        /// <summary>
+        /// Gets the file contents as readonly <see cref="Stream"/>.
+        /// </summary>
+        /// <returns>The <see cref="Stream"/>.</returns>
+        public abstract Stream Read();
+
+        /// <summary>
+        /// The root relative path of the item.
+        /// </summary>
+        public virtual string CombinedPath
+        {
+            get
+            {
+                if (BasePath == "/")
+                {
+                    return Path;
+                }
+                else
+                {
+                    return BasePath + Path;
+                }
+            }
+        }
+
+        /// <summary>
+        /// The extension of the file.
+        /// </summary>
+        public virtual string Extension
+        {
+            get
+            {
+                var index = Filename.LastIndexOf('.');
+                if (index == -1)
+                {
+                    return null;
+                }
+                else
+                {
+                    return Filename.Substring(index);
+                }
+            }
+        }
+
+        /// <summary>
+        /// The name of the file including the extension.
+        /// </summary>
+        public virtual string Filename
+        {
+            get
+            {
+                var index = Path.LastIndexOf('/');
+                return Path.Substring(index + 1);
+            }
+        }
+
+        /// <summary>
+        /// Path relative to <see cref="BasePath"/> without the extension.
+        /// </summary>
+        public virtual string PathWithoutExtension
+        {
+            get
+            {
+                var index = Path.LastIndexOf('.');
+                if (index == -1)
+                {
+                    return Path;
+                }
+                else
+                {
+                    return Path.Substring(0, index);
+                }
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Razor.Evolution.Test/RazorProjectItemTest.cs

@@ -0,0 +1,133 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.IO;
+using Xunit;
+
+namespace Microsoft.AspNetCore.Razor.Evolution
+{
+    public class RazorProjectItemTest
+    {
+        [Fact]
+        public void CombinedPath_ReturnsPathIfBasePathIsEmpty()
+        {
+            // Arrange
+            var emptyBasePath = "/";
+            var path = "/foo/bar.cshtml";
+            var projectItem = new TestRazorProjectItem(emptyBasePath, path);
+
+            // Act
+            var combinedPath = projectItem.CombinedPath;
+
+            // Assert
+            Assert.Equal(path, combinedPath);
+        }
+
+        [Theory]
+        [InlineData("/root", "/root/foo/bar.cshtml")]
+        [InlineData("root/subdir", "root/subdir/foo/bar.cshtml")]
+        public void CombinedPath_ConcatsPaths(string basePath, string expected)
+        {
+            // Arrange
+            var path = "/foo/bar.cshtml";
+            var projectItem = new TestRazorProjectItem(basePath, path);
+
+            // Act
+            var combinedPath = projectItem.CombinedPath;
+
+            // Assert
+            Assert.Equal(expected, combinedPath);
+        }
+
+        [Theory]
+        [InlineData("/Home/Index")]
+        [InlineData("EditUser")]
+        public void Extension_ReturnsNullIfFileDoesNotHaveExtension(string path)
+        {
+            // Arrange
+            var projectItem = new TestRazorProjectItem("/views", path);
+
+            // Act
+            var extension = projectItem.Extension;
+
+            // Assert
+            Assert.Null(extension);
+        }
+
+        [Theory]
+        [InlineData("/Home/Index.cshtml", ".cshtml")]
+        [InlineData("/Home/Index.en-gb.cshtml", ".cshtml")]
+        [InlineData("EditUser.razor", ".razor")]
+        public void Extension_ReturnsFileExtension(string path, string expected)
+        {
+            // Arrange
+            var projectItem = new TestRazorProjectItem("/views", path);
+
+            // Act
+            var extension = projectItem.Extension;
+
+            // Assert
+            Assert.Equal(expected, extension);
+        }
+
+        [Theory]
+        [InlineData("Home/Index.cshtml", "Index.cshtml")]
+        [InlineData("/Accounts/Customers/Manage-en-us.razor", "Manage-en-us.razor")]
+        public void FileName_ReturnsFileNameWithExtension(string path, string expected)
+        {
+            // Arrange
+            var projectItem = new TestRazorProjectItem("/", path);
+
+            // Act
+            var fileName = projectItem.Filename;
+
+            // Assert
+            Assert.Equal(expected, fileName);
+        }
+
+        [Theory]
+        [InlineData("Home/Index", "Home/Index")]
+        [InlineData("Home/Index.cshtml", "Home/Index")]
+        [InlineData("/Accounts/Customers/Manage.en-us.razor", "/Accounts/Customers/Manage.en-us")]
+        [InlineData("/Accounts/Customers/Manage-en-us.razor", "/Accounts/Customers/Manage-en-us")]
+        public void PathWithoutExtension_ExcludesExtension(string path, string expected)
+        {
+            // Arrange
+            var projectItem = new TestRazorProjectItem("/", path);
+
+            // Act
+            var fileName = projectItem.PathWithoutExtension;
+
+            // Assert
+            Assert.Equal(expected, fileName);
+        }
+
+
+        private class TestRazorProjectItem : RazorProjectItem
+        {
+            public TestRazorProjectItem(string basePath, string path)
+            {
+                BasePath = basePath;
+                Path = path;
+            }
+
+            public override string BasePath { get; }
+
+            public override string Path { get; }
+
+            public override string PhysicalPath
+            {
+                get
+                {
+                    throw new NotImplementedException();
+                }
+            }
+
+            public override Stream Read()
+            {
+                throw new NotImplementedException();
+            }
+        }
+    }
+}