Implemented handling of <copy-from> recipe step

src/Backend/Services.Interfaces/Fetchers/FetcherBase.cs

@@ -175,6 +175,10 @@ private void Cook([NotNull] Recipe recipe, ManifestDigest manifestDigest)
             foreach (var archive in recipe.Steps.OfType<Archive>())
                 ArchiveExtractor.VerifySupport(archive.MimeType);
 
+            // Download any other Implementations required by the Recipe
+            foreach (var copyFromStep in recipe.Steps.OfType<CopyFromStep>())
+                Fetch(new[] {copyFromStep.Implementation});
+
             var downloadedFiles = new List<TemporaryFile>();
             try
             {

src/Backend/Store/Implementations/Build/RecipeUtils.cs

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2016 Bastian Eicher, Roland Leopold Walkling
+ * Copyright 2010-2017 Bastian Eicher
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Lesser Public License as published by
@@ -78,7 +78,8 @@ public static TemporaryDirectory Apply([NotNull] this Recipe recipe, [NotNull, I
                             step.Apply(downloadedEnum.Current, workingDir);
                         },
                         (RemoveStep step) => step.Apply(workingDir),
-                        (RenameStep step) => step.Apply(workingDir)
+                        (RenameStep step) => step.Apply(workingDir),
+                        (CopyFromStep step) => step.Apply(workingDir, handler, tag)
                     }.Dispatch(recipe.Steps);
                     // ReSharper restore AccessToDisposedClosure
                 }
@@ -251,5 +252,53 @@ public static void Apply([NotNull] this RenameStep step, [NotNull] TemporaryDire
             FlagUtils.Rename(Path.Combine(workingDir, FlagUtils.XbitFile), source, destination);
             FlagUtils.Rename(Path.Combine(workingDir, FlagUtils.SymlinkFile), source, destination);
         }
+
+        /// <summary>
+        /// Applies a <see cref="CopyFromStep"/> to a <see cref="TemporaryDirectory"/>.
+        /// </summary>
+        /// <param name="step">The <see cref="Archive"/> to apply.</param>
+        /// <param name="workingDir">The <see cref="TemporaryDirectory"/> to apply the changes to.</param>
+        /// <param name="handler">A callback object used when the the user needs to be informed about progress.</param>
+        /// <param name="tag">A tag used to associate composite task with a specific operation; can be null.</param>
+        /// <exception cref="IOException">A path specified in <paramref name="step"/> is illegal.</exception>
+        public static void Apply([NotNull] this CopyFromStep step, [NotNull] TemporaryDirectory workingDir, ITaskHandler handler, [CanBeNull] object tag = null)
+        {
+            #region Sanity checks
+            if (step == null) throw new ArgumentNullException(nameof(step));
+            if (workingDir == null) throw new ArgumentNullException(nameof(workingDir));
+            #endregion
+
+            #region Path validation
+            string source = FileUtils.UnifySlashes(step.Source ?? "");
+            string destination = FileUtils.UnifySlashes(step.Destination ?? "");
+            if (FileUtils.IsBreakoutPath(source)) throw new IOException(string.Format(Resources.RecipeInvalidPath, source));
+            if (FileUtils.IsBreakoutPath(destination)) throw new IOException(string.Format(Resources.RecipeInvalidPath, destination));
+            #endregion
+
+            var store = StoreFactory.CreateDefault();
+            string sourcePath = Path.Combine(store.GetPath(step.Implementation), source);
+
+            if (Directory.Exists(sourcePath))
+            {
+                handler.RunTask(new CloneDirectory(sourcePath, workingDir)
+                {
+                    TargetSuffix = destination,
+                    UseHardlinks = true,
+                    Tag = tag
+                });
+            }
+            else if (File.Exists(sourcePath))
+            {
+                if (string.IsNullOrEmpty(destination)) throw new IOException(string.Format(Resources.RecipeCopyFromDestinationMissing, step));
+                handler.RunTask(new CloneFile(sourcePath, workingDir)
+                {
+                    TargetSuffix = Path.GetDirectoryName(destination),
+                    TargetFileName = Path.GetFileName(destination),
+                    UseHardlinks = true,
+                    Tag = tag
+                });
+            }
+            else throw new IOException(string.Format(Resources.RecipeCopyFromSourceMissing, step));
+        }
     }
 }

src/Backend/Store/Properties/Resources.de.resx

@@ -333,6 +333,12 @@ Sie können die Datei '{0}' löschen, um das Problem zu beheben.</value>
     <value>Es gab ein Problem beim Laden des Konfigurationswerts '{0}'.
 Sie können die Datei '{1}' löschen, um das Problem zu beheben. Dabei gehen womöglich auch andere Einstellungen verloren.</value>
   </data>
+  <data name="RecipeCopyFromDestinationMissing" xml:space="preserve">
+    <value>Das Ziel für den '{0}' Schritt muss gesetzt sein, da die Quelle eine Datei und kein Verzeichnis ist.</value>
+  </data>
+  <data name="RecipeCopyFromSourceMissing" xml:space="preserve">
+    <value>Die Quelle, die im '{0}' Schritt angegeben ist, existiert nicht.</value>
+  </data>
   <data name="RecipeFileNotDownloaded" xml:space="preserve">
     <value>Eine Datei auf die im &lt;recipe&gt; verwießen wird wurde nicht heruntergeladen.</value>
   </data>

src/Backend/Store/Properties/Resources.resx

@@ -333,6 +333,12 @@ You can delete the file '{0}' to fix the problem.</value>
     <value>There was a problem loading the configuration value '{0}'.
 You can delete the file '{1}' to fix the problem. Other settings may also be lost.</value>
   </data>
+  <data name="RecipeCopyFromDestinationMissing" xml:space="preserve">
+    <value>The destination for the '{0}' step must be specified because the source is a file and not a directory.</value>
+  </data>
+  <data name="RecipeCopyFromSourceMissing" xml:space="preserve">
+    <value>The source specified in the '{0}' step does not exist.</value>
+  </data>
   <data name="RecipeFileNotDownloaded" xml:space="preserve">
     <value>A file referenced in the &lt;recipe&gt; was not downloaded.</value>
   </data>

src/Backend/UnitTests/Store/Implementations/Build/RecipeUtilsTest.cs

@@ -17,6 +17,7 @@
 
 using System;
 using System.IO;
+using System.Linq;
 using FluentAssertions;
 using NanoByte.Common.Storage;
 using NanoByte.Common.Streams;
@@ -169,6 +170,71 @@ public void TestApplyRecipeRename()
             }
         }
 
+        [Test]
+        public void TestApplyRecipeCopyFrom()
+        {
+            using (new LocationsRedirect("0install-unit-tests"))
+            {
+                string existingImplPath = Path.Combine(StoreConfig.GetImplementationDirs().First(), "sha1new=123");
+                new TestRoot
+                {
+                    new TestDirectory("source")
+                    {
+                        new TestFile("file"),
+                        new TestFile("executable") {IsExecutable = true},
+                        new TestSymlink("symlink", "target")
+                    }
+                }.Build(existingImplPath);
+
+                using (var archiveFile = new TemporaryFile("0install-unit-tests"))
+                {
+                    typeof(ArchiveExtractorTest).CopyEmbeddedToFile("testArchive.zip", archiveFile);
+
+                    var downloadedFiles = new[] {archiveFile};
+                    var recipe = new Recipe
+                    {
+                        Steps =
+                        {
+                            new CopyFromStep
+                            {
+                                Source = "source",
+                                Destination = "dest",
+                                Implementation = new Implementation
+                                {
+                                    ManifestDigest = new ManifestDigest(sha1New: "123")
+                                }
+                            },
+                            new CopyFromStep
+                            {
+                                Source = "source/file",
+                                Destination = "dest/symlink", // Overwrite existing symlink with regular file
+                                Implementation = new Implementation
+                                {
+                                    ManifestDigest = new ManifestDigest(sha1New: "123")
+                                }
+                            }
+                        }
+                    };
+
+                    using (var recipeDir = recipe.Apply(downloadedFiles, new SilentTaskHandler()))
+                    {
+                        new TestRoot
+                        {
+                            new TestDirectory("dest")
+                            {
+                                new TestFile("file"),
+                                new TestFile("executable") {IsExecutable = true},
+                                new TestFile("symlink")
+                            }
+                        }.Verify(recipeDir);
+                    }
+                }
+
+                FileUtils.DisableWriteProtection(existingImplPath);
+                Directory.Delete(existingImplPath, recursive: true);
+            }
+        }
+
         [Test]
         public void TestApplyRecipeExceptions()
         {