velopack/src/lib-csharp/Locators/OsxVelopackLocator.cs

using System;
using System.IO;
using System.Runtime.Versioning;
using Microsoft.Extensions.Logging;
using NuGet.Versioning;
using Velopack.NuGet;
using Velopack.Util;

namespace Velopack.Locators
{
    /// <summary>
    /// The default for OSX. All application files will remain in the '.app'.
    /// All additional files (log, etc) will be placed in a temporary directory.
    /// </summary>
    [SupportedOSPlatform("osx")]
    public class OsxVelopackLocator : VelopackLocator
    {
        /// <inheritdoc />
        public override string? AppId { get; }

        /// <inheritdoc />
        public override string? RootAppDir { get; }

        /// <inheritdoc />
        public override string? UpdateExePath { get; }

        /// <inheritdoc />
        public override SemanticVersion? CurrentlyInstalledVersion { get; }

        /// <inheritdoc />
        public override string? AppContentDir => RootAppDir;

        /// <inheritdoc />
        public override string? AppTempDir => CreateSubDirIfDoesNotExist(TempUtil.GetDefaultTempBaseDirectory(), AppId);

        /// <inheritdoc />
        public override string? PackagesDir => CreateSubDirIfDoesNotExist(CachesAppDir, "packages");

        private string? CachesAppDir => CreateSubDirIfDoesNotExist(CachesVelopackDir, AppId);
        private string? CachesVelopackDir => CreateSubDirIfDoesNotExist(CachesDir, "velopack");
        private string? CachesDir => CreateSubDirIfDoesNotExist(LibraryDir, "Caches");
        private string? LibraryDir => CreateSubDirIfDoesNotExist(HomeDir, "Library");
        private string? HomeDir => Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);

        /// <inheritdoc />
        public override string? Channel { get; }
        
        /// <inheritdoc />
        public override uint ProcessId { get; }
        
        /// <inheritdoc />
        public override string ProcessExePath { get; }

        /// <summary>
        /// Creates a new <see cref="OsxVelopackLocator"/> and auto-detects the
        /// app information from metadata embedded in the .app.
        /// </summary>
        public OsxVelopackLocator(string currentProcessPath, uint currentProcessId, ILogger logger)
            : base(logger)
        {
            if (!VelopackRuntimeInfo.IsOSX)
                throw new NotSupportedException("Cannot instantiate OsxLocator on a non-osx system.");
            
            ProcessId = currentProcessId;
            var ourPath = ProcessExePath = currentProcessPath;

            Log.Info($"Initialising {nameof(OsxVelopackLocator)}");

            // are we inside a .app?
            var ix = ourPath.IndexOf(".app/", StringComparison.InvariantCultureIgnoreCase);
            if (ix <= 0) {
                Log.Warn($"Unable to locate .app root from '{ourPath}'");
                return;
            }

            var appPath = ourPath.Substring(0, ix + 4);
            var contentsDir = Path.Combine(appPath, "Contents");
            var macosDir = Path.Combine(contentsDir, "MacOS");
            var updateExe = Path.Combine(macosDir, "UpdateMac");
            var metadataPath = Path.Combine(macosDir, CoreUtil.SpecVersionFileName);

            if (File.Exists(updateExe) && PackageManifest.TryParseFromFile(metadataPath, out var manifest)) {
                Log.Info("Located valid manifest file at: " + metadataPath);
                AppId = manifest.Id;
                RootAppDir = appPath;
                UpdateExePath = updateExe;
                CurrentlyInstalledVersion = manifest.Version;
                Channel = manifest.Channel;
            }
        }
    }
}