Introduce LibraryInstallationGoalState

src/LibraryManager.Contracts/FileHelpers.cs

@@ -374,13 +374,25 @@ public static bool IsUnderRootDirectory(string filePath, string rootDirectory)
                 && normalizedFilePath.StartsWith(normalizedRootDirectory, StringComparison.OrdinalIgnoreCase);
         }
 
-        internal static string NormalizePath(string path)
+        /// <summary>
+        /// Normalizes the path string so it can be easily compared.
+        /// </summary>
+        /// <remarks>
+        /// Result will be lowercase and have any trailing slashes removed.
+        /// </remarks>
+        public static string NormalizePath(string path)
         {
             if (string.IsNullOrEmpty(path))
             {
                 return path;
             }
 
+            // If the path is a URI, we don't want to normalize it
+            if (IsHttpUri(path))
+            {
+                return path;
+            }
+
             // net451 does not have the OSPlatform apis to determine if the OS is windows or not.
             // This also does not handle the fact that MacOS can be configured to be either sensitive or insenstive 
             // to the casing.
@@ -394,5 +406,14 @@ internal static string NormalizePath(string path)
 
             return Path.GetFullPath(path).TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar);
         }
+
+        /// <summary>
+        /// Determines if the path is an HTTP or HTTPS Uri
+        /// </summary>
+        public static bool IsHttpUri(string path)
+        {
+            return Uri.TryCreate(path, UriKind.Absolute, out Uri uri)
+                && (uri.Scheme == Uri.UriSchemeHttp || uri.Scheme == Uri.UriSchemeHttps);
+        }
     }
 }

src/LibraryManager.Contracts/IProvider.cs

@@ -66,5 +66,10 @@ public interface IProvider
         /// </summary>
         /// <param name="library"></param>
         string GetSuggestedDestination(ILibrary library);
+
+        /// <summary>
+        /// Gets the goal state of the library installation.  Does not imply actual installation.
+        /// </summary>
+        Task<OperationResult<LibraryInstallationGoalState>> GetInstallationGoalStateAsync(ILibraryInstallationState installationState, CancellationToken cancellationToken);
     }
 }

src/LibraryManager.Contracts/LibraryInstallationGoalState.cs

@@ -0,0 +1,64 @@
+// 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;
+using System.IO;
+
+namespace Microsoft.Web.LibraryManager.Contracts
+{
+    /// <summary>
+    /// Represents a goal state of deployed files mapped to their sources from the local cache
+    /// </summary>
+    public class LibraryInstallationGoalState
+    {
+        /// <summary>
+        /// Initialize a new goal state from the desired installation state.
+        /// </summary>
+        public LibraryInstallationGoalState(ILibraryInstallationState installationState, Dictionary<string, string> installedFiles)
+        {
+            InstallationState = installationState;
+            InstalledFiles = installedFiles;
+        }
+
+        /// <summary>
+        /// The ILibraryInstallationState that this goal state was computed from.
+        /// </summary>
+        public ILibraryInstallationState InstallationState { get; }
+
+        /// <summary>
+        /// Mapping from destination file to source file
+        /// </summary>
+        public IDictionary<string, string> InstalledFiles { get; }
+
+        /// <summary>
+        /// Returns whether the goal is in an achieved state - that is, all files are up to date.
+        /// </summary>
+        /// <remarks>
+        /// This is intended to serve as a fast check compared to restoring the files.  
+        /// If there isn't a faster way to verify that a file is up to date, this method should
+        /// return false to indicate that a restore can't be skipped.
+        /// </remarks>
+        public bool IsAchieved()
+        {
+            foreach (KeyValuePair<string, string> kvp in InstalledFiles)
+            {
+                // If the source file is a remote Uri, we have no way to determine if it matches the installed file.
+                // So we will always reinstall the library in this case.
+                if (FileHelpers.IsHttpUri(kvp.Value))
+                {
+                    return false;
+                }
+
+                var destinationFile = new FileInfo(kvp.Key);
+                var cacheFile = new FileInfo(kvp.Value);
+
+                if (!destinationFile.Exists || !cacheFile.Exists || !FileHelpers.AreFilesUpToDate(destinationFile, cacheFile))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+    }
+}

src/LibraryManager.Contracts/PredefinedErrors.cs

@@ -17,11 +17,11 @@ namespace Microsoft.Web.LibraryManager.Contracts
     public static class PredefinedErrors
     {
         /// <summary>
-        /// Represents an unhandled exception that occured in the provider.
+        /// Represents an unhandled exception that occurred in the provider.
         /// </summary>
         /// <remarks>
         /// An <see cref="IProvider.InstallAsync"/> should never throw and this error
-        /// should be used as when catching generic exeptions.
+        /// should be used as when catching generic exceptions.
         /// </remarks>
         /// <returns>The error code LIB000</returns>
         public static IError UnknownException()
@@ -198,6 +198,12 @@ public static IError DuplicateLibrariesInManifest(string duplicateLibrary)
         public static IError FileNameMustNotBeEmpty(string libraryId)
             => new Error("LIB020", string.Format(Text.ErrorFilePathIsEmpty, libraryId));
 
+        /// <summary>
+        /// A library mapping does not have a destination specified
+        /// </summary>
+        public static IError DestinationNotSpecified(string libraryId)
+            => new Error("LIB021", string.Format(Text.ErrorDestinationNotSpecified, libraryId));
+
         /// <summary>
         /// The manifest must specify a version
         /// </summary>

src/LibraryManager.Contracts/Resources/Text.resx

@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -187,6 +187,9 @@ Valid files are {2}</value>
   <data name="ErrorFilePathIsEmpty" xml:space="preserve">
     <value>The library "{0}" cannot specify a file with an empty name</value>
   </data>
+  <data name="ErrorDestinationNotSpecified" xml:space="preserve">
+    <value>The "{0}" library is missing a destination.</value>
+  </data>
   <data name="ErrorMissingManifestVersion" xml:space="preserve">
     <value>The Library Manager manifest must specify a version.</value>
   </data>

src/LibraryManager/Manifest.cs

@@ -204,8 +204,6 @@ public Manifest Clone()
             string destination,
             CancellationToken cancellationToken)
         {
-            ILibraryOperationResult result;
-
             var desiredState = new LibraryInstallationState()
             {
                 Name = libraryName,
@@ -236,14 +234,14 @@ public Manifest Clone()
                 return conflictResults;
             }
 
-            result = await provider.InstallAsync(desiredState, cancellationToken).ConfigureAwait(false);
+            ILibraryOperationResult installResult = await provider.InstallAsync(desiredState, cancellationToken);
 
-            if (result.Success)
+            if (installResult.Success)
             {
                 AddLibrary(desiredState);
             }
 
-            return result;
+            return installResult;
         }
 
         private ILibraryInstallationState SetDefaultProviderIfNeeded(LibraryInstallationState desiredState)
@@ -510,7 +508,7 @@ private async Task<IEnumerable<FileIdentifier>> GetAllManifestFilesWithVersionsA
                 return allFiles.SelectMany(f => f).Distinct();
             }
 
-           return new List<FileIdentifier>();
+            return new List<FileIdentifier>();
         }
 
         private async Task<IEnumerable<FileIdentifier>> GetFilesWithVersionsAsync(ILibraryInstallationState state)
@@ -567,41 +565,31 @@ private async Task<IEnumerable<FileIdentifier>> GetFilesWithVersionsAsync(ILibra
             try
             {
                 IProvider provider = _dependencies.GetProvider(state.ProviderId);
-                ILibraryOperationResult updatedStateResult = await provider.UpdateStateAsync(state, CancellationToken.None).ConfigureAwait(false);
-
-                if (updatedStateResult.Success)
+                OperationResult<LibraryInstallationGoalState> getGoalState = await provider.GetInstallationGoalStateAsync(state, cancellationToken).ConfigureAwait(false);
+                if (!getGoalState.Success)
                 {
-                    List<string> filesToDelete = new List<string>();
-                    state = updatedStateResult.InstallationState;
-
-                    foreach (string file in state.Files)
+                    return new LibraryOperationResult(state, [.. getGoalState.Errors])
                     {
-                        var url = new Uri(file, UriKind.RelativeOrAbsolute);
-
-                        if (!url.IsAbsoluteUri)
-                        {
-                            string relativePath = Path.Combine(state.DestinationPath, file).Replace('\\', '/');
-                            filesToDelete.Add(relativePath);
-                        }
-                    }
+                        Cancelled = getGoalState.Cancelled,
+                    };
+                }
 
-                    bool success = true;
-                    if (deleteFilesFunction != null)
-                    {
-                        success = await deleteFilesFunction.Invoke(filesToDelete).ConfigureAwait(false);
-                    }
+                LibraryInstallationGoalState goalState = getGoalState.Result;
 
-                    if (success)
-                    {
-                        return LibraryOperationResult.FromSuccess(updatedStateResult.InstallationState);
-                    }
-                    else
-                    {
-                        return LibraryOperationResult.FromError(PredefinedErrors.CouldNotDeleteLibrary(libraryId));
-                    }
+                bool success = true;
+                if (deleteFilesFunction != null)
+                {
+                    success = await deleteFilesFunction.Invoke(goalState.InstalledFiles.Keys).ConfigureAwait(false);
                 }
 
-                return updatedStateResult;
+                if (success)
+                {
+                    return LibraryOperationResult.FromSuccess(goalState.InstallationState);
+                }
+                else
+                {
+                    return LibraryOperationResult.FromError(PredefinedErrors.CouldNotDeleteLibrary(libraryId));
+                }
             }
             catch (OperationCanceledException)
             {