Cleanup error marshaling and generating code

LibGit2Sharp/Core/Ensure.cs

@@ -62,26 +62,19 @@ public static void Success(int result, bool allowPositiveResult = false)
                 return;
             }
 
-            string errorMessage;
-            GitError error = NativeMethods.giterr_last().MarshalAsGitError();
-
-
+            var error = NativeMethods.giterr_last();
             if (error == null)
             {
-                error = new GitError { Klass = GitErrorType.Unknown, Message = IntPtr.Zero };
-                errorMessage = "No error message has been provided by the native library";
-            }
-            else
-            {
-                errorMessage = Utf8Marshaler.FromNative(error.Message);
+                throw new LibGit2SharpException(
+                    (GitErrorCode)result,
+                    GitErrorCategory.Unknown,
+                    "No error message has been provided by the native library");
             }
 
             throw new LibGit2SharpException(
-                String.Format(CultureInfo.InvariantCulture, "An error was raised by libgit2. Class = {0} ({1}).{2}{3}",
-                              error.Klass,
-                              result,
-                              Environment.NewLine,
-                              errorMessage));
+                (GitErrorCode)result,
+                error.Category,
+                Utf8Marshaler.FromNative(error.Message));
         }
 
         /// <summary>
@@ -108,8 +101,8 @@ public static void GitObjectIsNotNull(GitObject gitObject, string identifier)
             }
 
             throw new LibGit2SharpException(string.Format(CultureInfo.InvariantCulture,
-                                                     "No valid git object identified by '{0}' exists in the repository.",
-                                                     identifier));
+                "No valid git object identified by '{0}' exists in the repository.",
+                identifier));
         }
     }
 }

LibGit2Sharp/Core/GitError.cs

@@ -7,6 +7,6 @@ namespace LibGit2Sharp.Core
     internal class GitError
     {
         public IntPtr Message;
-        public GitErrorType Klass;
+        public GitErrorCategory Category;
     }
 }

LibGit2Sharp/Core/GitErrorType.cs → LibGit2Sharp/Core/GitErrorCategory.cs

@@ -1,6 +1,6 @@
 namespace LibGit2Sharp.Core
 {
-    internal enum GitErrorType
+    public enum GitErrorCategory
     {
         Unknown = -1,
         NoMemory,

LibGit2Sharp/Core/GitErrorCode.cs

@@ -1,6 +1,6 @@
 namespace LibGit2Sharp.Core
 {
-    internal enum GitErrorCode
+    public enum GitErrorCode
     {
         Ok = 0,
         Error = -1,

LibGit2Sharp/Core/GitErrorMarshaler.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace LibGit2Sharp.Core
+{
+    internal class GitErrorMarshaler : ICustomMarshaler
+    {
+        static readonly GitErrorMarshaler staticInstance = new GitErrorMarshaler();
+
+        public void CleanUpManagedData(object managedObj)
+        {
+        }
+
+        public void CleanUpNativeData(IntPtr pNativeData)
+        {
+            if (pNativeData != IntPtr.Zero)
+            {
+                Marshal.FreeHGlobal(pNativeData);
+            }
+        }
+
+        public int GetNativeDataSize()
+        {
+            return -1;
+        }
+
+        public IntPtr MarshalManagedToNative(object managedObj)
+        {
+            throw new NotImplementedException();
+        }
+
+        public object MarshalNativeToManaged(IntPtr pNativeData)
+        {
+            return NativeToGitError(pNativeData);
+        }
+
+        protected GitError NativeToGitError(IntPtr pNativeData)
+        {
+            return (GitError)Marshal.PtrToStructure(pNativeData, typeof(GitError));
+        }
+
+        public static ICustomMarshaler GetInstance(string cookie)
+        {
+            return staticInstance;
+        }
+    }
+}

LibGit2Sharp/Core/NativeMethods.cs

@@ -65,7 +65,8 @@ public static bool RepositoryStateChecker(RepositorySafeHandle repositoryPtr, Fu
         }
 
         [DllImport(libgit2)]
-        public static extern GitErrorSafeHandle giterr_last();
+        [return: MarshalAs(UnmanagedType.CustomMarshaler, MarshalTypeRef = typeof(GitErrorMarshaler))]
+        public static extern GitError giterr_last();
 
         [DllImport(libgit2)]
         public static extern int git_blob_create_fromdisk(

LibGit2Sharp/LibGit2Sharp.csproj

@@ -78,10 +78,10 @@
     <Compile Include="Core\GitDiff.cs" />
     <Compile Include="Core\GitDiffExtensions.cs" />
     <Compile Include="Core\GitError.cs" />
-    <Compile Include="Core\GitErrorType.cs" />
+    <Compile Include="Core\GitErrorCategory.cs" />
+    <Compile Include="Core\GitErrorMarshaler.cs" />
     <Compile Include="Core\GitNoteData.cs" />
     <Compile Include="Core\GitObjectExtensions.cs" />
-    <Compile Include="Core\Handles\GitErrorSafeHandle.cs" />
     <Compile Include="Core\Handles\NoteSafeHandle.cs" />
     <Compile Include="Core\Handles\ObjectDatabaseSafeHandle.cs" />
     <Compile Include="Core\Handles\DiffListSafeHandle.cs" />

LibGit2Sharp/LibGit2SharpException.cs

@@ -1,5 +1,6 @@
 using System;
-using System.Runtime.Serialization;
+using System.Globalization;
+using LibGit2Sharp.Core;
 
 namespace LibGit2Sharp
 {
@@ -39,16 +40,29 @@ public LibGit2Exception(string message, Exception innerException)
     /// <summary>
     ///   The exception that is thrown when an error occurs during application execution.
     /// </summary>
-    [Serializable]
     public class LibGit2SharpException : Exception
     {
+        readonly GitErrorCode code;
+        readonly GitErrorCategory category;
+        readonly bool isLibraryError;
+
         /// <summary>
         ///   Initializes a new instance of the <see cref = "LibGit2SharpException" /> class.
         /// </summary>
         public LibGit2SharpException()
         {
         }
 
+        /// <summary>
+        ///   Initializes a new instance of the <see cref = "LibGit2SharpException" /> class.
+        /// </summary>
+        public LibGit2SharpException(GitErrorCode code, GitErrorCategory category, string message) : base(message)
+        {
+            Data["libgit2.code"] = this.code = code;
+            Data["libgit2.class"] = this.category = category;
+            isLibraryError = true;
+        }
+
         /// <summary>
         ///   Initializes a new instance of the <see cref = "LibGit2SharpException" /> class with a specified error message.
         /// </summary>
@@ -69,13 +83,30 @@ public LibGit2SharpException(string message, Exception innerException)
         }
 
         /// <summary>
-        ///   Initializes a new instance of the <see cref = "LibGit2SharpException" /> class with a serialized data.
+        /// The specific libgit2 error code.
         /// </summary>
-        /// <param name = "info">The <see cref="SerializationInfo "/> that holds the serialized object data about the exception being thrown.</param>
-        /// <param name = "context">The <see cref="StreamingContext"/> that contains contextual information about the source or destination.</param>
-        protected LibGit2SharpException(SerializationInfo info, StreamingContext context)
-            : base(info, context)
+        public GitErrorCode Code
+        {
+            get { return Data.Contains("libgit2.code") ? (GitErrorCode)Data["libgit2.code"] : GitErrorCode.Error; }
+        }
+
+        /// <summary>
+        /// The specific libgit2 error class.
+        /// </summary>
+        public GitErrorCategory Category
+        {
+            get { return Data.Contains("libgit2.class") ? (GitErrorCategory)Data["libgit2.class"] : GitErrorCategory.Unknown; }
+        }
+
+        public override string ToString()
         {
+            return isLibraryError
+                ? String.Format(CultureInfo.InvariantCulture, "An error was raised by libgit2. Class = {0} ({1}).{2}{3}",
+                    category,
+                    code,
+                    Environment.NewLine,
+                    Message)
+                : base.ToString();
         }
     }
 }