Merge pull request #24 from thrawn01/variadic-setdefault

added variadic defaults to SetDefault

README.md

@@ -274,6 +274,10 @@ var config struct {
 }
 holster.SetDefault(&config.Foo, "default")
 holster.SetDefault(&config.Bar, 200)
+
+// Supply additional default values and SetDefault will
+// choose the first default that is not of zero value
+//  holster.SetDefault(&config.Foo, os.Getenv("FOO"), "default")
 ```
 
 ## GetEnv

set_default.go

@@ -15,7 +15,9 @@ limitations under the License.
 */
 package holster
 
-import "reflect"
+import (
+	"reflect"
+)
 
 // If 'value' is empty or of zero value, assign the default value.
 // This panics if the value is not a pointer or if value and
@@ -27,14 +29,25 @@ import "reflect"
 //	}
 // 	holster.SetDefault(&config.Foo, "default")
 // 	holster.SetDefault(&config.Bar, 200)
-func SetDefault(value, defaultValue interface{}) {
-	v := reflect.ValueOf(value)
-	if v.Kind() != reflect.Ptr {
-		panic("holster.IfEmpty: Expected first argument to be of type reflect.Ptr")
+//
+// Supply additional default values and SetDefault will
+// choose the first default that is not of zero value
+//  holster.SetDefault(&config.Foo, os.Getenv("FOO"), "default")
+func SetDefault(dest interface{}, defaultValue ...interface{}) {
+	d := reflect.ValueOf(dest)
+	if d.Kind() != reflect.Ptr {
+		panic("holster.SetDefault: Expected first argument to be of type reflect.Ptr")
 	}
-	v = reflect.Indirect(v)
-	if IsZeroValue(v) {
-		v.Set(reflect.ValueOf(defaultValue))
+	d = reflect.Indirect(d)
+	if IsZeroValue(d) {
+		// Use the first non zero default value we find
+		for _, value := range defaultValue {
+			v := reflect.ValueOf(value)
+			if !IsZeroValue(v) {
+				d.Set(reflect.ValueOf(value))
+				return
+			}
+		}
 	}
 }
 

set_default_test.go

@@ -53,6 +53,25 @@ func (s *SetDefaultTestSuite) TestIfEmpty(c *C) {
 	c.Assert(conf.Bar, Equals, 500)
 }
 
+func (s *SetDefaultTestSuite) TestIfDefaultPrecedence(c *C) {
+	var conf struct {
+		Foo string
+		Bar string
+	}
+	c.Assert(conf.Foo, Equals, "")
+	c.Assert(conf.Bar, Equals, "")
+
+	// Should use the final default value
+	envValue := ""
+	holster.SetDefault(&conf.Foo, envValue, "default")
+	c.Assert(conf.Foo, Equals, "default")
+
+	// Should use envValue
+	envValue = "bar"
+	holster.SetDefault(&conf.Bar, envValue, "default")
+	c.Assert(conf.Bar, Equals, "bar")
+}
+
 func (s *SetDefaultTestSuite) TestIsEmpty(c *C) {
 	var count64 int64
 	var thing string
@@ -83,7 +102,7 @@ func (s *SetDefaultTestSuite) TestIfEmptyTypePanic(c *C) {
 func (s *SetDefaultTestSuite) TestIfEmptyNonPtrPanic(c *C) {
 	defer func() {
 		if r := recover(); r != nil {
-			c.Assert(r, Equals, "holster.IfEmpty: Expected first argument to be of type reflect.Ptr")
+			c.Assert(r, Equals, "holster.SetDefault: Expected first argument to be of type reflect.Ptr")
 		}
 	}()
 

version

@@ -1 +1 @@
-1.7.0
+1.7.1