Bari.Core.Build.Cache.FileBuildCache.CopyIfDifferent C# (CSharp) Method

        private void CopyIfDifferent(IFileSystemDirectory sourceDirectory, string sourceFileName, IFileSystemDirectory targetRoot, string targetRelativePath)
        {
            bool copy = true;
            long sourceSize = sourceDirectory.GetFileSize(sourceFileName);
            if (targetRoot.Exists(targetRelativePath))
            {
                long targetSize = targetRoot.GetFileSize(targetRelativePath);
                if (sourceSize == targetSize)
                {
                    var sourceChecksum = Task.Factory.StartNew(() => ComputeChecksum(md5a, sourceDirectory, sourceFileName));
                    var targetChecksum = Task.Factory.StartNew(() => ComputeChecksum(md5b, targetRoot, targetRelativePath));

                    copy = !sourceChecksum.Result.SequenceEqual(targetChecksum.Result);
                }
            }

            if (copy)
            {
                sourceDirectory.CopyFile(sourceFileName, targetRoot, targetRelativePath);
            }
            else
            {
                log.DebugFormat("File {0} is the same as the cached one", targetRelativePath);
            }
        }