Make OdbBackend expose valid backend return codes

Author: nulltoken

LibGit2Sharp.Tests/OdbBackendFixture.cs

@@ -182,10 +182,10 @@ public override int Read(ObjectId oid, out Stream data, out ObjectType objectTyp
 
                     objectType = gitObject.ObjectType;
 
-                    return GIT_OK;
+                    return (int)ReturnCode.GIT_OK;
                 }
 
-                return GIT_ENOTFOUND;
+                return (int)ReturnCode.GIT_ENOTFOUND;
             }
 
             public override int ReadPrefix(byte[] shortOid, int len, out byte[] oid, out Stream data, out ObjectType objectType)
@@ -228,7 +228,7 @@ public override int ReadPrefix(byte[] shortOid, int len, out byte[] oid, out Str
 
                     if (null != gitObjectAlreadyFound)
                     {
-                        return GIT_EAMBIGUOUS;
+                        return (int)ReturnCode.GIT_EAMBIGUOUS;
                     }
 
                     gitObjectAlreadyFound = gitObject;
@@ -246,37 +246,47 @@ public override int ReadPrefix(byte[] shortOid, int len, out byte[] oid, out Str
                         data.Write(chunk, 0, chunk.Length);
                     }
 
-                    return GIT_OK;
+                    return (int)ReturnCode.GIT_OK;
                 }
 
-                return GIT_ENOTFOUND;
+                return (int)ReturnCode.GIT_ENOTFOUND;
             }
 
             public override int Write(ObjectId oid, Stream dataStream, long length, ObjectType objectType)
+            {
+                var buffer = ReadBuffer(dataStream, length);
+
+                m_objectIdToContent.Add(oid,
+                    new MockGitObject(oid, objectType, length, new List<byte[]> { buffer }));
+
+                return (int)ReturnCode.GIT_OK;
+            }
+
+            private static byte[] ReadBuffer(Stream dataStream, long length)
             {
                 if (length > int.MaxValue)
                 {
-                    return GIT_ERROR;
+                    throw new InvalidOperationException(
+                        string.Format("Provided length ({0}) exceeds int.MaxValue ({1}).", length, int.MaxValue));
                 }
 
                 var buffer = new byte[length];
                 int bytesRead = dataStream.Read(buffer, 0, (int)length);
 
                 if (bytesRead != (int)length)
                 {
-                    return GIT_ERROR;
+                    throw new InvalidOperationException(
+                        string.Format("Too short buffer. {0} bytes were expected. {1} have been successfully read.", length,
+                            bytesRead));
                 }
-
-                m_objectIdToContent.Add(oid, new MockGitObject(oid, objectType, length, new List<byte[]> { buffer }));
-
-                return GIT_OK;
+                return buffer;
             }
 
             public override int WriteStream(long length, ObjectType objectType, out OdbBackendStream stream)
             {
                 stream = new MockOdbBackendStream(this, objectType, length);
 
-                return GIT_OK;
+                return (int)ReturnCode.GIT_OK;
             }
 
             public override bool Exists(ObjectId oid)
@@ -287,11 +297,6 @@ public override bool Exists(ObjectId oid)
             private readonly Dictionary<ObjectId, MockGitObject> m_objectIdToContent =
                 new Dictionary<ObjectId, MockGitObject>();
 
-            private const int GIT_OK = 0;
-            private const int GIT_ERROR = -1;
-            private const int GIT_ENOTFOUND = -3;
-            private const int GIT_EAMBIGUOUS = -5;
-
             #region Unimplemented
 
             public override int ReadHeader(ObjectId oid, out int length, out ObjectType objectType)
@@ -311,7 +316,7 @@ public override int ForEach(ForEachCallback callback)
                     callback(mockGitObject.Key);
                 }
 
-                return GIT_OK;
+                return (int)ReturnCode.GIT_OK;
             }
 
             #endregion
@@ -345,19 +350,11 @@ public override bool CanWrite
 
                 public override int Write(Stream dataStream, long length)
                 {
-                    if (length > Int32.MaxValue)
-                        return GIT_ERROR;
-
-                    var buffer = new byte[length];
-
-                    int bytesRead = dataStream.Read(buffer, 0, (int)length);
-
-                    if (bytesRead != (int)length)
-                        return GIT_ERROR;
+                    var buffer = ReadBuffer(dataStream, length);
 
                     m_chunks.Add(buffer);
 
-                    return GIT_OK;
+                    return (int)ReturnCode.GIT_OK;
                 }
 
                 public override int FinalizeWrite(ObjectId oid)
@@ -366,15 +363,16 @@ public override int FinalizeWrite(ObjectId oid)
 
                     if (totalLength != m_length)
                     {
-                        return GIT_ERROR;
+                        throw new InvalidOperationException(
+                            string.Format("Invalid final length. {0} was expected. The total size of the received chunks is {1}.", m_length, totalLength));
                     }
 
                     var backend = (MockOdbBackend)Backend;
 
                     backend.m_objectIdToContent.Add(oid,
                         new MockGitObject(oid, m_type, m_length, m_chunks));
 
-                    return GIT_OK;
+                    return (int)ReturnCode.GIT_OK;
                 }
 
                 private readonly List<byte[]> m_chunks = new List<byte[]>();

LibGit2Sharp/OdbBackend.cs

@@ -624,5 +624,26 @@ protected enum OdbBackendOperations
             /// </summary>
             ForEach = 128,
         }
+
+        /// <summary>
+        /// Libgit2 expected backend return codes.
+        /// </summary>
+        protected enum ReturnCode
+        {
+            /// <summary>
+            /// No error has occured.
+            /// </summary>
+            GIT_OK = 0,
+
+            /// <summary>
+            /// No object matching the oid, or short oid, can be found in the backend.
+            /// </summary>
+            GIT_ENOTFOUND = -3,
+
+            /// <summary>
+            /// The given short oid is ambiguous.
+            /// </summary>
+            GIT_EAMBIGUOUS = -5,
+        }
     }
 }