public static async Task FetchArtifact()

in src/build/Infra/ArtifactsApi.cs [134:186]
37 lines of code
7 McCabe index (conditional complexity)

        public static async Task<(bool wasAlreadyPresent, string localPath)> FetchArtifact(
            BuildContext ctx, ArtifactPackage ap, bool forceSwitch,
            Action<long, long> fetchProgress = null, Action<long> fetchComplete = null)
        {
            var localPath = Path.Combine(ctx.InDir, ap.FileName);

            if (!forceSwitch && File.Exists(localPath))
                return (true, localPath);

            if (!ap.IsDownloadable)
                throw new Exception($"{ap.FileName} is missing {nameof(ap.Url)}");

            localPath = Path.Combine(ctx.InDir, Path.GetFileName(ap.Url));

            Directory.CreateDirectory(ctx.InDir);

            using var http = new HttpClient();
            using var stm = await http.GetStreamAsync(ap.Url);
            using var fs = File.Open(localPath, FileMode.Create, FileAccess.Write);

            // Buffer size just shy of one that would get onto LOH
            // (hopefully ArrayPool will oblige...)

            var bytes = ArrayPool<byte>.Shared.Rent(81920);

            try
            {
                int bytesRead = 0;
                long bytesReadTotal = 0;

                while (true)
                {
                    if ((bytesRead = await stm.ReadAsync(bytes, 0, bytes.Length)) <= 0)
                        break;

                    bytesReadTotal += bytesRead;

                    var writeTask = fs.WriteAsync(bytes, 0, bytesRead);
                    fetchProgress?.Invoke(bytesRead, bytesReadTotal);

                    await writeTask;
                }

                fetchComplete?.Invoke(bytesReadTotal);
            }
            finally
            {
                if (bytes != null)
                    ArrayPool<byte>.Shared.Return(bytes);
            }

            return (false, localPath);
        }