1 files changed, 107 insertions, 0 deletions
diff --git a/main/src/addins/MonoDevelop.PackageManagement/NuGet.PackageManagement.UI/PackageCollection.cs b/main/src/addins/MonoDevelop.PackageManagement/NuGet.PackageManagement.UI/PackageCollection.cs
new file mode 100644
index 0000000000..c369377f40
--- /dev/null
+++ b/main/src/addins/MonoDevelop.PackageManagement/NuGet.PackageManagement.UI/PackageCollection.cs
@@ -0,0 +1,107 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using NuGet.Packaging.Core;
+using NuGet.ProjectManagement;
+using NuGet.Versioning;
+
+namespace NuGet.PackageManagement.UI
+{
+	/// <summary>
+	/// Wrapper class consolidating common queries against a collection of packages
+	/// </summary>
+	internal class PackageCollection : IEnumerable<PackageIdentity>
+	{
+		readonly PackageIdentity[] _packages;
+		readonly ISet<string> _uniqueIds = new HashSet<string> (StringComparer.OrdinalIgnoreCase);
+
+		public PackageCollection (PackageIdentity[] packages)
+		{
+			_packages = packages;
+			_uniqueIds.UnionWith (_packages.Select (p => p.Id));
+		}
+
+		public IEnumerator<PackageIdentity> GetEnumerator ()
+		{
+			return ((IEnumerable<PackageIdentity>)_packages).GetEnumerator ();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator ()
+		{
+			return ((IEnumerable<PackageIdentity>)_packages).GetEnumerator ();
+		}
+
+		public bool ContainsId (string packageId) => _uniqueIds.Contains (packageId);
+
+		public static async Task<PackageCollection> FromProjectsAsync (IEnumerable<NuGetProject> projects, CancellationToken cancellationToken)
+		{
+			var tasks = projects
+				.Select (project => project.GetInstalledPackagesAsync (cancellationToken));
+			var packageReferences = await Task.WhenAll (tasks);
+			var packages = packageReferences
+				.SelectMany (p => p)
+				.Where (p => p != null)
+				.Select (p => p.PackageIdentity)
+				.Distinct (PackageIdentity.Comparer)
+				.ToArray ();
+
+			return new PackageCollection (packages);
+		}
+	}
+
+	/// <summary>
+	/// Common package queries implementes as extension methods
+	/// </summary>
+	internal static class PackageCollectionExtensions
+	{
+		public static NuGetVersion[] GetPackageVersions (this IEnumerable<PackageIdentity> packages, string packageId)
+		{
+			return packages
+				.Where (p => StringComparer.OrdinalIgnoreCase.Equals (p.Id, packageId))
+				.Select (p => p.Version)
+				.ToArray ();
+		}
+
+		public static IEnumerable<IGrouping<string, NuGetVersion>> GroupById (this IEnumerable<PackageIdentity> packages)
+		{
+			return packages
+				.GroupBy (p => p.Id, p => p.Version, StringComparer.OrdinalIgnoreCase);
+		}
+
+		public static PackageIdentity[] GetLatest (this IEnumerable<PackageIdentity> packages)
+		{
+			return packages
+				.GroupById ()
+				.Select (g => new PackageIdentity (g.Key, g.MaxOrDefault ()))
+				.ToArray ();
+		}
+
+		public static PackageIdentity[] GetEarliest (this IEnumerable<PackageIdentity> packages)
+		{
+			return packages
+				.GroupById ()
+				.Select (g => new PackageIdentity (g.Key, g.MinOrDefault ()))
+				.ToArray ();
+		}
+	}
+
+	internal static class VersionCollectionExtensions
+	{
+		public static NuGetVersion MinOrDefault (this IEnumerable<NuGetVersion> versions)
+		{
+			return versions
+				.OrderBy (v => v, VersionComparer.Default)
+				.FirstOrDefault ();
+		}
+
+		public static NuGetVersion MaxOrDefault (this IEnumerable<NuGetVersion> versions)
+		{
+			return versions
+				.OrderByDescending (v => v, VersionComparer.Default)
+				.FirstOrDefault ();
+		}
+	}
+}
+\ No newline at end of file