Merge pull request #550 from github-for-unity/enhancements/md5-folder

Adding functionality to md5 an entire folder

Author: StanleyGoldman

src/GitHub.Api/Extensions/FileSystemExtensions.cs

@@ -1,12 +1,14 @@
 using System;
+using System.IO;
+using System.Linq;
 using System.Security.Cryptography;
 using System.Text;
 
 namespace GitHub.Unity
 {
     static class FileSystemExtensions
     {
-        public static string CalculateMD5(this IFileSystem fileSystem, string file)
+        public static string CalculateFileMD5(this IFileSystem fileSystem, string file)
         {
             byte[] computeHash;
             using (var md5 = MD5.Create())
@@ -17,7 +19,39 @@ public static string CalculateMD5(this IFileSystem fileSystem, string file)
                 }
             }
 
-            return BitConverter.ToString(computeHash).Replace("-", string.Empty);
+            return BitConverter.ToString(computeHash).Replace("-", string.Empty).ToLower();
+        }
+
+        public static string CalculateFolderMD5(this IFileSystem fileSystem, string path, bool includeContents = true)
+        {
+            //https://stackoverflow.com/questions/3625658/creating-hash-for-folder
+
+            var filePaths = fileSystem.GetFiles(path, "*", SearchOption.AllDirectories)
+                .OrderBy(p => p)
+                .ToArray();
+
+            using (var md5 = MD5.Create())
+            {
+                foreach (var filePath in filePaths)
+                {
+                    // hash path
+                    var relativeFilePath = filePath.Substring(path.Length + 1);
+                    var pathBytes = Encoding.UTF8.GetBytes(relativeFilePath);
+                    md5.TransformBlock(pathBytes, 0, pathBytes.Length, pathBytes, 0);
+
+                    if (includeContents)
+                    {
+                        // hash contents
+                        var contentBytes = File.ReadAllBytes(filePath);
+                        md5.TransformBlock(contentBytes, 0, contentBytes.Length, contentBytes, 0);
+                    }
+                }
+
+                //Handles empty filePaths case
+                md5.TransformFinalBlock(new byte[0], 0, 0);
+
+                return BitConverter.ToString(md5.Hash).Replace("-", "").ToLower();
+            }
         }
     }
 }

src/GitHub.Api/IO/IFileSystem.cs

@@ -35,6 +35,7 @@ public interface IFileSystem
         void WriteAllText(string path, string contents);
         void WriteAllText(string path, string contents, Encoding encoding);
         void WriteAllLines(string path, string[] contents);
+        byte[] ReadAllBytes(string path);
         string ReadAllText(string path);
         string ReadAllText(string path, Encoding encoding);
         Stream OpenRead(string path);

src/GitHub.Api/Installer/GitInstaller.cs

@@ -90,7 +90,7 @@ public bool IsGitLfsExtracted()
                 return false;
             }
 
-            var calculateMd5 = environment.FileSystem.CalculateMD5(GitLfsExecutablePath);
+            var calculateMd5 = environment.FileSystem.CalculateFileMD5(GitLfsExecutablePath);
             logger.Trace("GitLFS MD5: {0}", calculateMd5);
             var md5 = environment.IsWindows ? WindowsGitLfsExecutableMD5 : MacGitLfsExecutableMD5;
             if (String.Compare(calculateMd5, md5, true) != 0)

src/tests/IntegrationTests/Git/GitSetupTests.cs

@@ -41,7 +41,7 @@ public async Task InstallGit()
                 gitLfsDestinationPath = gitLfsDestinationPath.Combine("libexec", "git-core", "git-lfs.exe");
                 gitLfsDestinationPath.FileExists().Should().BeTrue();
 
-                var calculateMd5 = NPath.FileSystem.CalculateMD5(gitLfsDestinationPath);
+                var calculateMd5 = NPath.FileSystem.CalculateFileMD5(gitLfsDestinationPath);
                 Assert.IsTrue(string.Compare(calculateMd5, GitInstaller.WindowsGitLfsExecutableMD5, true) == 0);
 
                 setupDone = await gitSetup.SetupIfNeeded(new Progress<float>(x => percent = x));
@@ -83,7 +83,7 @@ public void VerifyWindowsGitLfsBundle()
 
             gitLfsPath.Exists().Should().BeTrue();
 
-            var calculateMd5 = NPath.FileSystem.CalculateMD5(gitLfsPath);
+            var calculateMd5 = NPath.FileSystem.CalculateFileMD5(gitLfsPath);
             calculateMd5.ToLower().Should().Be(GitInstaller.WindowsGitLfsExecutableMD5.ToLower());
         }
 
@@ -103,7 +103,7 @@ public void VerifyMacGitLfsBundle()
 
             gitLfsPath.Exists().Should().BeTrue();
 
-            var calculateMd5 = NPath.FileSystem.CalculateMD5(gitLfsPath);
+            var calculateMd5 = NPath.FileSystem.CalculateFileMD5(gitLfsPath);
             calculateMd5.ToLower().Should().Be(GitInstaller.MacGitLfsExecutableMD5.ToLower());
         }
     }