LibGit2RepositoryFactory.cs

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using LibGit2Sharp;
using LibGit2Sharp.Handlers;
using Microsoft.Extensions.Logging;
using System;
using System.Threading;
using System.Threading.Tasks;
using Tgstation.Server.Api.Models;
using Tgstation.Server.Host.Jobs;

namespace Tgstation.Server.Host.Components.Repository
{
    sealed class LibGit2RepositoryFactory : ILibGit2RepositoryFactory
    {
        readonly ILogger<LibGit2RepositoryFactory> logger;

        public LibGit2RepositoryFactory(ILogger<LibGit2RepositoryFactory> logger)
        {
            this.logger = logger ?? throw new ArgumentNullException(nameof(logger));
        }

        public LibGit2Sharp.IRepository CreateInMemory()
        {
            logger.LogTrace("Creating in-memory libgit2 repository...");
            var repo = new LibGit2Sharp.Repository();
            try
            {
                logger.LogTrace("Successfully created in-memory libgit2 repository.");
                return repo;
            }
            catch
            {
                repo.Dispose();
                throw;
            }
        }

        public Task<LibGit2Sharp.IRepository> CreateFromPath(string path, CancellationToken cancellationToken)
        {
            if (path == null)
                throw new ArgumentNullException(nameof(path));

            return Task.Factory.StartNew<LibGit2Sharp.IRepository>(
                () =>
                {
                    logger.LogTrace("Creating libgit2 repostory at {0}...", path);
                    return new LibGit2Sharp.Repository(path);
                },
                cancellationToken,
                TaskCreationOptions.LongRunning,
                TaskScheduler.Current);
        }

        public Task Clone(Uri url, CloneOptions cloneOptions, string path, CancellationToken cancellationToken) => Task.Factory.StartNew(() =>
        {
            try
            {
                logger.LogTrace("Cloning {0} into {1}...", url, path);
                LibGit2Sharp.Repository.Clone(url.ToString(), path, cloneOptions);
            }
            catch (UserCancelledException ex)
            {
                logger.LogTrace("Suppressing clone cancellation exception: {0}", ex);
                cancellationToken.ThrowIfCancellationRequested();
            }
        }, cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Current);

        public CredentialsHandler GenerateCredentialsHandler(string username, string password) => (a, b, supportedCredentialTypes) =>
        {
            var hasCreds = username != null;
            var supportsUserPass = supportedCredentialTypes.HasFlag(SupportedCredentialTypes.UsernamePassword);
            var supportsAnonymous = supportedCredentialTypes.HasFlag(SupportedCredentialTypes.Default);

            logger.LogTrace("Credentials requested. Present: {0}. Supports anonymous: {1}. Supports user/pass: {2}", hasCreds, supportsAnonymous, supportsUserPass);
            if (supportsUserPass && hasCreds)
                return new UsernamePasswordCredentials
                {
                    Username = username,
                    Password = password
                };

            if (supportsAnonymous)
                return new DefaultCredentials();

            if (supportsUserPass)
                throw new JobException(ErrorCode.RepoCredentialsRequired);

            throw new JobException(ErrorCode.RepoCannotAuthenticate);
        };
    }
}