From 7464a2351d307dba69271f2ba792779cb715f087 Mon Sep 17 00:00:00 2001
From: Justin Overfelt <joverfelt@gmail.com>
Date: Sat, 4 Jul 2015 13:42:16 -0400
Subject: [PATCH] Implement database/sql's Scanner interface. Fixes #5

---
 sql.go      | 40 ++++++++++++++++++++++++++++++++++++++++
 sql_test.go | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 93 insertions(+)
 create mode 100644 sql.go
 create mode 100644 sql_test.go

diff --git a/sql.go b/sql.go
new file mode 100644
index 0000000..2d7679e
--- /dev/null
+++ b/sql.go
@@ -0,0 +1,40 @@
+// Copyright 2015 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Scan implements sql.Scanner so UUIDs can be read from databases transparently
+// Currently, database types that map to string and []byte are supported. Please
+// consult database-specific driver documentation for matching types.
+func (uuid *UUID) Scan(src interface{}) error {
+	switch src.(type) {
+	case string:
+		// see uuid.Parse for required string format
+		parsed := Parse(src.(string))
+
+		if parsed == nil {
+			return errors.New("Scan: invalid UUID format")
+		}
+
+		*uuid = parsed
+	case []byte:
+		// assumes a simple slice of bytes, just check validity and store
+		u := UUID(src.([]byte))
+
+		if u.Variant() == Invalid {
+			return errors.New("Scan: invalid UUID format")
+		}
+
+		*uuid = u
+	default:
+		return fmt.Errorf("Scan: unable to scan type %T into UUID", src)
+	}
+
+	return nil
+}
diff --git a/sql_test.go b/sql_test.go
new file mode 100644
index 0000000..d643567
--- /dev/null
+++ b/sql_test.go
@@ -0,0 +1,53 @@
+// Copyright 2015 Google Inc.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package uuid
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestScan(t *testing.T) {
+	var stringTest string = "f47ac10b-58cc-0372-8567-0e02b2c3d479"
+	var byteTest []byte = Parse(stringTest)
+	var badTypeTest int = 6
+	var invalidTest string = "f47ac10b-58cc-0372-8567-0e02b2c3d4"
+	var invalidByteTest []byte = Parse(invalidTest)
+
+	var uuid UUID
+	err := (&uuid).Scan(stringTest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = (&uuid).Scan(byteTest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = (&uuid).Scan(badTypeTest)
+	if err == nil {
+		t.Error("int correctly parsed and shouldn't have")
+	}
+	if !strings.Contains(err.Error(), "unable to scan type") {
+		t.Error("attempting to parse an int returned an incorrect error message")
+	}
+
+	err = (&uuid).Scan(invalidTest)
+	if err == nil {
+		t.Error("invalid uuid was parsed without error")
+	}
+	if !strings.Contains(err.Error(), "invalid UUID") {
+		t.Error("attempting to parse an invalid UUID returned an incorrect error message")
+	}
+
+	err = (&uuid).Scan(invalidByteTest)
+	if err == nil {
+		t.Error("invalid byte uuid was parsed without error")
+	}
+	if !strings.Contains(err.Error(), "invalid UUID") {
+		t.Error("attempting to parse an invalid byte UUID returned an incorrect error message")
+	}
+}