Make Reference Hashable

SwiftGit2/References.swift

@@ -38,6 +38,17 @@ public struct Reference: ReferenceType {
 	}
 }
 
+extension Reference: Hashable {
+	public var hashValue: Int {
+		return longName.hashValue ^ oid.hashValue
+	}
+}
+
+public func == (lhs: Reference, rhs: Reference) -> Bool {
+	return lhs.longName == rhs.longName
+		&& lhs.oid == rhs.oid
+}
+
 /// A git branch.
 public struct Branch: ReferenceType {
 	/// The full name of the reference (e.g., `refs/heads/master`).

SwiftGit2Tests/ReferencesSpec.swift

@@ -34,5 +34,30 @@ class ReferenceSpec: QuickSpec {
 				expect(ref.oid).to(equal(OID(string: "c4ed03a6b7d7ce837d31d83757febbe84dd465fd")!))
 			}
 		}
+		
+		describe("==") {
+			it("should be true with equal references") {
+				let repo = Fixtures.simpleRepository
+				let ref1 = from_git_reference(repo, "refs/heads/master") { Reference($0) }
+				let ref2 = from_git_reference(repo, "refs/heads/master") { Reference($0) }
+				expect(ref1).to(equal(ref2))
+			}
+			
+			it("should be false with unequal references") {
+				let repo = Fixtures.simpleRepository
+				let ref1 = from_git_reference(repo, "refs/heads/master") { Reference($0) }
+				let ref2 = from_git_reference(repo, "refs/heads/another-branch") { Reference($0) }
+				expect(ref1).notTo(equal(ref2))
+			}
+		}
+
+		describe("hashValue") {
+			it("should be equal with equal references") {
+				let repo = Fixtures.simpleRepository
+				let ref1 = from_git_reference(repo, "refs/heads/master") { Reference($0) }
+				let ref2 = from_git_reference(repo, "refs/heads/master") { Reference($0) }
+				expect(ref1.hashValue).to(equal(ref2.hashValue))
+			}
+		}
 	}
 }