process/src/process/Buffered/BufferedCommandExtensions.cs

// Copyright (c) The Geekeey Authors
// SPDX-License-Identifier: EUPL-1.2

using System.Text;

namespace Geekeey.Process.Buffered;

/// <summary>
/// Buffered execution model.
/// </summary>
public static class BufferedCommandExtensions
{
	/// <inheritdoc cref="BufferedCommandExtensions"/>
	extension(Command command)
	{
		/// <summary>
		/// Executes the command asynchronously with buffering.
		/// Data written to the standard output and standard error streams is decoded as text
		/// and returned as part of the result object.
		/// </summary>
		/// <remarks>
		/// This method can be awaited.
		/// </remarks>
		public CommandTask<BufferedCommandResult> ExecuteBufferedAsync(Encoding standardOutputEncoding, Encoding standardErrorEncoding,
			CancellationToken cancellationToken = default)
		{
			var stdOutBuffer = new StringBuilder();
			var stdErrBuffer = new StringBuilder();

			var stdOutPipe = PipeTarget.Merge(command.StandardOutputPipe,
				PipeTarget.ToStringBuilder(stdOutBuffer, standardOutputEncoding));

			var stdErrPipe = PipeTarget.Merge(command.StandardErrorPipe,
				PipeTarget.ToStringBuilder(stdErrBuffer, standardErrorEncoding));

			var commandWithPipes = command
				.WithStandardOutputPipe(stdOutPipe)
				.WithStandardErrorPipe(stdErrPipe);

			return commandWithPipes
				.ExecuteAsync(cancellationToken)
				.Bind(async task =>
				{
					try
					{
						var result = await task;

						return new BufferedCommandResult(result.ExitCode, result.StartTime, result.ExitTime,
							stdOutBuffer.ToString(), stdErrBuffer.ToString());
					}
					catch (CommandExecutionException exception)
					{
						var message = $"""
									   Command execution failed, see the inner exception for details.
									   Standard error:
									   {stdErrBuffer.ToString().Trim()}
									   """;
						throw new CommandExecutionException(exception.Command, exception.ExitCode, message, exception);
					}
				});
		}

		/// <summary>
		/// Executes the command asynchronously with buffering.
		/// Data written to the standard output and standard error streams is decoded as text
		/// and returned as part of the result object.
		/// </summary>
		/// <remarks>
		/// This method can be awaited.
		/// </remarks>
		public CommandTask<BufferedCommandResult> ExecuteBufferedAsync(Encoding encoding,
			CancellationToken cancellationToken = default)
		{
			return command.ExecuteBufferedAsync(encoding, encoding, cancellationToken);
		}

		/// <summary>
		/// Executes the command asynchronously with buffering.
		/// Data written to the standard output and standard error streams is decoded as text
		/// and returned as part of the result object.
		/// Uses <see cref="Console.OutputEncoding" /> for decoding.
		/// </summary>
		/// <remarks>
		/// This method can be awaited.
		/// </remarks>
		public CommandTask<BufferedCommandResult> ExecuteBufferedAsync(CancellationToken cancellationToken = default)
		{
			return command.ExecuteBufferedAsync(Console.OutputEncoding, cancellationToken);
		}
	}
}