From 87f493d0800d4b24da8f80a030ea653f08d305e5 Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Mon, 18 Nov 2013 14:35:44 +0800
Subject: [PATCH] Add Scopes Support

---
 README.md    | 33 ++++++++++++++++++++++++++++++++-
 gorm_test.go | 32 ++++++++++++++++++++++++++++++++
 main.go      |  8 ++++++++
 model.go     |  3 ++-
 4 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index ec5ce59f..28ac7592 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ Yet Another ORM library for Go, aims for developer friendly
 * Logger Support
 * Bind struct with tag
 * Iteration Support via [Rows](#row--rows)
+* Scopes
 * sql.Scanner support
 * Every feature comes with tests
 * Convention Over Configuration
@@ -666,6 +667,37 @@ tx.Rollback()
 tx.Commit()
 ```
 
+## Scopes
+
+```go
+func AmountGreaterThan1000(d *gorm.DB) *gorm.DB {
+  d.Where("amount > ?", 1000)
+}
+
+func PaidWithCreditCard(d *gorm.DB) *gorm.DB {
+  d.Where("pay_mode_sign = ?", "C")
+}
+
+func PaidWithCod(d *gorm.DB) *gorm.DB {
+  d.Where("pay_mode_sign = ?", "C")
+}
+
+func OrderStatus(status []string) func (d *gorm.DB) *gorm.DB {
+  return func (d *gorm.DB) *gorm.DB {
+     return d.Scopes(AmountGreaterThan1000).Where("status in (?)", status)
+  }
+}
+
+db.Scopes(AmountGreaterThan1000, PaidWithCreditCard).Find(&orders)
+// Find all credit card orders and amount greater than 1000
+
+db.Scopes(AmountGreaterThan1000, PaidWithCod).Find(&orders)
+// Find all COD orders and amount greater than 1000
+
+db.Scopes(OrderStatus([]string{"paid", "shipped"})).Find(&orders)
+// Find all paid, shipped orders and amount greater than 1000
+```
+
 ## Logger
 
 Grom has builtin logger support, enable it with:
@@ -790,7 +822,6 @@ db.Where("email = ?", "x@example.org").Attrs(User{RegisteredIp: "111.111.111.111
 ```
 
 ## TODO
-* Scopes
 * Joins
 * Scan
 * AlertColumn, DropColumn, AddIndex, RemoveIndex
diff --git a/gorm_test.go b/gorm_test.go
index 1abf2e90..5d4f030c 100644
--- a/gorm_test.go
+++ b/gorm_test.go
@@ -1430,6 +1430,38 @@ func TestGroup(t *testing.T) {
 	}
 }
 
+func NameIn1And2(d *DB) *DB {
+	return d.Where("name in (?)", []string{"1", "2"})
+}
+
+func NameIn2And3(d *DB) *DB {
+	return d.Where("name in (?)", []string{"2", "3"})
+}
+
+func NameIn(names []string) func(d *DB) *DB {
+	return func(d *DB) *DB {
+		return d.Where("name in (?)", names)
+	}
+}
+
+func TestScopes(t *testing.T) {
+	var users1, users2, users3 []User
+	db.Scopes(NameIn1And2).Find(&users1)
+	if len(users1) != 2 {
+		t.Errorf("Should only have two users's name in 1, 2")
+	}
+
+	db.Scopes(NameIn1And2, NameIn2And3).Find(&users2)
+	if len(users2) != 1 {
+		t.Errorf("Should only have two users's name is 2")
+	}
+
+	db.Scopes(NameIn([]string{"1", "2"})).Find(&users3)
+	if len(users3) != 2 {
+		t.Errorf("Should only have two users's name is 2")
+	}
+}
+
 func TestHaving(t *testing.T) {
 	rows, err := db.Select("name, count(*) as total").Table("users").Group("name").Having("name IN (?)", []string{"2", "3"}).Rows()
 
diff --git a/main.go b/main.go
index eec0fbd6..be8b8981 100644
--- a/main.go
+++ b/main.go
@@ -93,6 +93,14 @@ func (s *DB) Includes(value interface{}) *DB {
 	return s.clone().search.includes(value).db
 }
 
+func (s *DB) Scopes(funcs ...func(*DB) *DB) *DB {
+	c := s
+	for _, f := range funcs {
+		c = f(c)
+	}
+	return c
+}
+
 func (s *DB) Unscoped() *DB {
 	return s.clone().search.unscoped().db
 }
diff --git a/model.go b/model.go
index 65d8d622..0b54b2bb 100644
--- a/model.go
+++ b/model.go
@@ -74,6 +74,8 @@ func (m *Model) fields(operation string) (fields []*Field) {
 
 	structs := getStructs(indirect_value.Type())
 	c := make(chan *Field, len(structs))
+	defer close(c)
+
 	for _, field_struct := range structs {
 		go func(field_struct reflect.StructField, c chan *Field) {
 			var field Field
@@ -110,7 +112,6 @@ func (m *Model) fields(operation string) (fields []*Field) {
 	for i := 0; i < len(structs); i++ {
 		fields = append(fields, <-c)
 	}
-	close(c)
 
 	if len(m._cache_fields) == 0 {
 		m._cache_fields = map[string][]*Field{}