initial commit

vendor/github.com/jmoiron/sqlx/reflectx/README.md

@@ -0,0 +1,17 @@
+# reflectx
+
+The sqlx package has special reflect needs.  In particular, it needs to:
+
+* be able to map a name to a field
+* understand embedded structs
+* understand mapping names to fields by a particular tag
+* user specified name -> field mapping functions
+
+These behaviors mimic the behaviors by the standard library marshallers and also the
+behavior of standard Go accessors.
+
+The first two are amply taken care of by `Reflect.Value.FieldByName`, and the third is
+addressed by `Reflect.Value.FieldByNameFunc`, but these don't quite understand struct
+tags in the ways that are vital to most marshalers, and they are slow.
+
+This reflectx package extends reflect to achieve these goals.

vendor/github.com/jmoiron/sqlx/reflectx/reflect.go

@@ -0,0 +1,371 @@
+// Package reflectx implements extensions to the standard reflect lib suitable
+// for implementing marshaling and unmarshaling packages.  The main Mapper type
+// allows for Go-compatible named attribute access, including accessing embedded
+// struct attributes and the ability to use  functions and struct tags to
+// customize field names.
+//
+package reflectx
+
+import (
+	"fmt"
+	"reflect"
+	"runtime"
+	"strings"
+	"sync"
+)
+
+// A FieldInfo is a collection of metadata about a struct field.
+type FieldInfo struct {
+	Index    []int
+	Path     string
+	Field    reflect.StructField
+	Zero     reflect.Value
+	Name     string
+	Options  map[string]string
+	Embedded bool
+	Children []*FieldInfo
+	Parent   *FieldInfo
+}
+
+// A StructMap is an index of field metadata for a struct.
+type StructMap struct {
+	Tree  *FieldInfo
+	Index []*FieldInfo
+	Paths map[string]*FieldInfo
+	Names map[string]*FieldInfo
+}
+
+// GetByPath returns a *FieldInfo for a given string path.
+func (f StructMap) GetByPath(path string) *FieldInfo {
+	return f.Paths[path]
+}
+
+// GetByTraversal returns a *FieldInfo for a given integer path.  It is
+// analogous to reflect.FieldByIndex.
+func (f StructMap) GetByTraversal(index []int) *FieldInfo {
+	if len(index) == 0 {
+		return nil
+	}
+
+	tree := f.Tree
+	for _, i := range index {
+		if i >= len(tree.Children) || tree.Children[i] == nil {
+			return nil
+		}
+		tree = tree.Children[i]
+	}
+	return tree
+}
+
+// Mapper is a general purpose mapper of names to struct fields.  A Mapper
+// behaves like most marshallers, optionally obeying a field tag for name
+// mapping and a function to provide a basic mapping of fields to names.
+type Mapper struct {
+	cache      map[reflect.Type]*StructMap
+	tagName    string
+	tagMapFunc func(string) string
+	mapFunc    func(string) string
+	mutex      sync.Mutex
+}
+
+// NewMapper returns a new mapper which optionally obeys the field tag given
+// by tagName.  If tagName is the empty string, it is ignored.
+func NewMapper(tagName string) *Mapper {
+	return &Mapper{
+		cache:   make(map[reflect.Type]*StructMap),
+		tagName: tagName,
+	}
+}
+
+// NewMapperTagFunc returns a new mapper which contains a mapper for field names
+// AND a mapper for tag values.  This is useful for tags like json which can
+// have values like "name,omitempty".
+func NewMapperTagFunc(tagName string, mapFunc, tagMapFunc func(string) string) *Mapper {
+	return &Mapper{
+		cache:      make(map[reflect.Type]*StructMap),
+		tagName:    tagName,
+		mapFunc:    mapFunc,
+		tagMapFunc: tagMapFunc,
+	}
+}
+
+// NewMapperFunc returns a new mapper which optionally obeys a field tag and
+// a struct field name mapper func given by f.  Tags will take precedence, but
+// for any other field, the mapped name will be f(field.Name)
+func NewMapperFunc(tagName string, f func(string) string) *Mapper {
+	return &Mapper{
+		cache:   make(map[reflect.Type]*StructMap),
+		tagName: tagName,
+		mapFunc: f,
+	}
+}
+
+// TypeMap returns a mapping of field strings to int slices representing
+// the traversal down the struct to reach the field.
+func (m *Mapper) TypeMap(t reflect.Type) *StructMap {
+	m.mutex.Lock()
+	mapping, ok := m.cache[t]
+	if !ok {
+		mapping = getMapping(t, m.tagName, m.mapFunc, m.tagMapFunc)
+		m.cache[t] = mapping
+	}
+	m.mutex.Unlock()
+	return mapping
+}
+
+// FieldMap returns the mapper's mapping of field names to reflect values.  Panics
+// if v's Kind is not Struct, or v is not Indirectable to a struct kind.
+func (m *Mapper) FieldMap(v reflect.Value) map[string]reflect.Value {
+	v = reflect.Indirect(v)
+	mustBe(v, reflect.Struct)
+
+	r := map[string]reflect.Value{}
+	tm := m.TypeMap(v.Type())
+	for tagName, fi := range tm.Names {
+		r[tagName] = FieldByIndexes(v, fi.Index)
+	}
+	return r
+}
+
+// FieldByName returns a field by the its mapped name as a reflect.Value.
+// Panics if v's Kind is not Struct or v is not Indirectable to a struct Kind.
+// Returns zero Value if the name is not found.
+func (m *Mapper) FieldByName(v reflect.Value, name string) reflect.Value {
+	v = reflect.Indirect(v)
+	mustBe(v, reflect.Struct)
+
+	tm := m.TypeMap(v.Type())
+	fi, ok := tm.Names[name]
+	if !ok {
+		return v
+	}
+	return FieldByIndexes(v, fi.Index)
+}
+
+// FieldsByName returns a slice of values corresponding to the slice of names
+// for the value.  Panics if v's Kind is not Struct or v is not Indirectable
+// to a struct Kind.  Returns zero Value for each name not found.
+func (m *Mapper) FieldsByName(v reflect.Value, names []string) []reflect.Value {
+	v = reflect.Indirect(v)
+	mustBe(v, reflect.Struct)
+
+	tm := m.TypeMap(v.Type())
+	vals := make([]reflect.Value, 0, len(names))
+	for _, name := range names {
+		fi, ok := tm.Names[name]
+		if !ok {
+			vals = append(vals, *new(reflect.Value))
+		} else {
+			vals = append(vals, FieldByIndexes(v, fi.Index))
+		}
+	}
+	return vals
+}
+
+// TraversalsByName returns a slice of int slices which represent the struct
+// traversals for each mapped name.  Panics if t is not a struct or Indirectable
+// to a struct.  Returns empty int slice for each name not found.
+func (m *Mapper) TraversalsByName(t reflect.Type, names []string) [][]int {
+	t = Deref(t)
+	mustBe(t, reflect.Struct)
+	tm := m.TypeMap(t)
+
+	r := make([][]int, 0, len(names))
+	for _, name := range names {
+		fi, ok := tm.Names[name]
+		if !ok {
+			r = append(r, []int{})
+		} else {
+			r = append(r, fi.Index)
+		}
+	}
+	return r
+}
+
+// FieldByIndexes returns a value for a particular struct traversal.
+func FieldByIndexes(v reflect.Value, indexes []int) reflect.Value {
+	for _, i := range indexes {
+		v = reflect.Indirect(v).Field(i)
+		// if this is a pointer, it's possible it is nil
+		if v.Kind() == reflect.Ptr && v.IsNil() {
+			alloc := reflect.New(Deref(v.Type()))
+			v.Set(alloc)
+		}
+		if v.Kind() == reflect.Map && v.IsNil() {
+			v.Set(reflect.MakeMap(v.Type()))
+		}
+	}
+	return v
+}
+
+// FieldByIndexesReadOnly returns a value for a particular struct traversal,
+// but is not concerned with allocating nil pointers because the value is
+// going to be used for reading and not setting.
+func FieldByIndexesReadOnly(v reflect.Value, indexes []int) reflect.Value {
+	for _, i := range indexes {
+		v = reflect.Indirect(v).Field(i)
+	}
+	return v
+}
+
+// Deref is Indirect for reflect.Types
+func Deref(t reflect.Type) reflect.Type {
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	return t
+}
+
+// -- helpers & utilities --
+
+type kinder interface {
+	Kind() reflect.Kind
+}
+
+// mustBe checks a value against a kind, panicing with a reflect.ValueError
+// if the kind isn't that which is required.
+func mustBe(v kinder, expected reflect.Kind) {
+	k := v.Kind()
+	if k != expected {
+		panic(&reflect.ValueError{Method: methodName(), Kind: k})
+	}
+}
+
+// methodName is returns the caller of the function calling methodName
+func methodName() string {
+	pc, _, _, _ := runtime.Caller(2)
+	f := runtime.FuncForPC(pc)
+	if f == nil {
+		return "unknown method"
+	}
+	return f.Name()
+}
+
+type typeQueue struct {
+	t  reflect.Type
+	fi *FieldInfo
+	pp string // Parent path
+}
+
+// A copying append that creates a new slice each time.
+func apnd(is []int, i int) []int {
+	x := make([]int, len(is)+1)
+	for p, n := range is {
+		x[p] = n
+	}
+	x[len(x)-1] = i
+	return x
+}
+
+// getMapping returns a mapping for the t type, using the tagName, mapFunc and
+// tagMapFunc to determine the canonical names of fields.
+func getMapping(t reflect.Type, tagName string, mapFunc, tagMapFunc func(string) string) *StructMap {
+	m := []*FieldInfo{}
+
+	root := &FieldInfo{}
+	queue := []typeQueue{}
+	queue = append(queue, typeQueue{Deref(t), root, ""})
+
+	for len(queue) != 0 {
+		// pop the first item off of the queue
+		tq := queue[0]
+		queue = queue[1:]
+		nChildren := 0
+		if tq.t.Kind() == reflect.Struct {
+			nChildren = tq.t.NumField()
+		}
+		tq.fi.Children = make([]*FieldInfo, nChildren)
+
+		// iterate through all of its fields
+		for fieldPos := 0; fieldPos < nChildren; fieldPos++ {
+			f := tq.t.Field(fieldPos)
+
+			fi := FieldInfo{}
+			fi.Field = f
+			fi.Zero = reflect.New(f.Type).Elem()
+			fi.Options = map[string]string{}
+
+			var tag, name string
+			if tagName != "" && strings.Contains(string(f.Tag), tagName+":") {
+				tag = f.Tag.Get(tagName)
+				name = tag
+			} else {
+				if mapFunc != nil {
+					name = mapFunc(f.Name)
+				}
+			}
+
+			parts := strings.Split(name, ",")
+			if len(parts) > 1 {
+				name = parts[0]
+				for _, opt := range parts[1:] {
+					kv := strings.Split(opt, "=")
+					if len(kv) > 1 {
+						fi.Options[kv[0]] = kv[1]
+					} else {
+						fi.Options[kv[0]] = ""
+					}
+				}
+			}
+
+			if tagMapFunc != nil {
+				tag = tagMapFunc(tag)
+			}
+
+			fi.Name = name
+
+			if tq.pp == "" || (tq.pp == "" && tag == "") {
+				fi.Path = fi.Name
+			} else {
+				fi.Path = fmt.Sprintf("%s.%s", tq.pp, fi.Name)
+			}
+
+			// if the name is "-", disabled via a tag, skip it
+			if name == "-" {
+				continue
+			}
+
+			// skip unexported fields
+			if len(f.PkgPath) != 0 && !f.Anonymous {
+				continue
+			}
+
+			// bfs search of anonymous embedded structs
+			if f.Anonymous {
+				pp := tq.pp
+				if tag != "" {
+					pp = fi.Path
+				}
+
+				fi.Embedded = true
+				fi.Index = apnd(tq.fi.Index, fieldPos)
+				nChildren := 0
+				ft := Deref(f.Type)
+				if ft.Kind() == reflect.Struct {
+					nChildren = ft.NumField()
+				}
+				fi.Children = make([]*FieldInfo, nChildren)
+				queue = append(queue, typeQueue{Deref(f.Type), &fi, pp})
+			} else if fi.Zero.Kind() == reflect.Struct || (fi.Zero.Kind() == reflect.Ptr && fi.Zero.Type().Elem().Kind() == reflect.Struct) {
+				fi.Index = apnd(tq.fi.Index, fieldPos)
+				fi.Children = make([]*FieldInfo, Deref(f.Type).NumField())
+				queue = append(queue, typeQueue{Deref(f.Type), &fi, fi.Path})
+			}
+
+			fi.Index = apnd(tq.fi.Index, fieldPos)
+			fi.Parent = tq.fi
+			tq.fi.Children[fieldPos] = &fi
+			m = append(m, &fi)
+		}
+	}
+
+	flds := &StructMap{Index: m, Tree: root, Paths: map[string]*FieldInfo{}, Names: map[string]*FieldInfo{}}
+	for _, fi := range flds.Index {
+		flds.Paths[fi.Path] = fi
+		if fi.Name != "" && !fi.Embedded {
+			flds.Names[fi.Path] = fi
+		}
+	}
+
+	return flds
+}

vendor/github.com/jmoiron/sqlx/reflectx/reflect_test.go

@@ -0,0 +1,587 @@
+package reflectx
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func ival(v reflect.Value) int {
+	return v.Interface().(int)
+}
+
+func TestBasic(t *testing.T) {
+	type Foo struct {
+		A int
+		B int
+		C int
+	}
+
+	f := Foo{1, 2, 3}
+	fv := reflect.ValueOf(f)
+	m := NewMapperFunc("", func(s string) string { return s })
+
+	v := m.FieldByName(fv, "A")
+	if ival(v) != f.A {
+		t.Errorf("Expecting %d, got %d", ival(v), f.A)
+	}
+	v = m.FieldByName(fv, "B")
+	if ival(v) != f.B {
+		t.Errorf("Expecting %d, got %d", f.B, ival(v))
+	}
+	v = m.FieldByName(fv, "C")
+	if ival(v) != f.C {
+		t.Errorf("Expecting %d, got %d", f.C, ival(v))
+	}
+}
+
+func TestBasicEmbedded(t *testing.T) {
+	type Foo struct {
+		A int
+	}
+
+	type Bar struct {
+		Foo // `db:""` is implied for an embedded struct
+		B   int
+		C   int `db:"-"`
+	}
+
+	type Baz struct {
+		A   int
+		Bar `db:"Bar"`
+	}
+
+	m := NewMapperFunc("db", func(s string) string { return s })
+
+	z := Baz{}
+	z.A = 1
+	z.B = 2
+	z.C = 4
+	z.Bar.Foo.A = 3
+
+	zv := reflect.ValueOf(z)
+	fields := m.TypeMap(reflect.TypeOf(z))
+
+	if len(fields.Index) != 5 {
+		t.Errorf("Expecting 5 fields")
+	}
+
+	// for _, fi := range fields.Index {
+	// 	log.Println(fi)
+	// }
+
+	v := m.FieldByName(zv, "A")
+	if ival(v) != z.A {
+		t.Errorf("Expecting %d, got %d", z.A, ival(v))
+	}
+	v = m.FieldByName(zv, "Bar.B")
+	if ival(v) != z.Bar.B {
+		t.Errorf("Expecting %d, got %d", z.Bar.B, ival(v))
+	}
+	v = m.FieldByName(zv, "Bar.A")
+	if ival(v) != z.Bar.Foo.A {
+		t.Errorf("Expecting %d, got %d", z.Bar.Foo.A, ival(v))
+	}
+	v = m.FieldByName(zv, "Bar.C")
+	if _, ok := v.Interface().(int); ok {
+		t.Errorf("Expecting Bar.C to not exist")
+	}
+
+	fi := fields.GetByPath("Bar.C")
+	if fi != nil {
+		t.Errorf("Bar.C should not exist")
+	}
+}
+
+func TestEmbeddedSimple(t *testing.T) {
+	type UUID [16]byte
+	type MyID struct {
+		UUID
+	}
+	type Item struct {
+		ID MyID
+	}
+	z := Item{}
+
+	m := NewMapper("db")
+	m.TypeMap(reflect.TypeOf(z))
+}
+
+func TestBasicEmbeddedWithTags(t *testing.T) {
+	type Foo struct {
+		A int `db:"a"`
+	}
+
+	type Bar struct {
+		Foo     // `db:""` is implied for an embedded struct
+		B   int `db:"b"`
+	}
+
+	type Baz struct {
+		A   int `db:"a"`
+		Bar     // `db:""` is implied for an embedded struct
+	}
+
+	m := NewMapper("db")
+
+	z := Baz{}
+	z.A = 1
+	z.B = 2
+	z.Bar.Foo.A = 3
+
+	zv := reflect.ValueOf(z)
+	fields := m.TypeMap(reflect.TypeOf(z))
+
+	if len(fields.Index) != 5 {
+		t.Errorf("Expecting 5 fields")
+	}
+
+	// for _, fi := range fields.index {
+	// 	log.Println(fi)
+	// }
+
+	v := m.FieldByName(zv, "a")
+	if ival(v) != z.Bar.Foo.A { // the dominant field
+		t.Errorf("Expecting %d, got %d", z.Bar.Foo.A, ival(v))
+	}
+	v = m.FieldByName(zv, "b")
+	if ival(v) != z.B {
+		t.Errorf("Expecting %d, got %d", z.B, ival(v))
+	}
+}
+
+func TestFlatTags(t *testing.T) {
+	m := NewMapper("db")
+
+	type Asset struct {
+		Title string `db:"title"`
+	}
+	type Post struct {
+		Author string `db:"author,required"`
+		Asset  Asset  `db:""`
+	}
+	// Post columns: (author title)
+
+	post := Post{Author: "Joe", Asset: Asset{Title: "Hello"}}
+	pv := reflect.ValueOf(post)
+
+	v := m.FieldByName(pv, "author")
+	if v.Interface().(string) != post.Author {
+		t.Errorf("Expecting %s, got %s", post.Author, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "title")
+	if v.Interface().(string) != post.Asset.Title {
+		t.Errorf("Expecting %s, got %s", post.Asset.Title, v.Interface().(string))
+	}
+}
+
+func TestNestedStruct(t *testing.T) {
+	m := NewMapper("db")
+
+	type Details struct {
+		Active bool `db:"active"`
+	}
+	type Asset struct {
+		Title   string  `db:"title"`
+		Details Details `db:"details"`
+	}
+	type Post struct {
+		Author string `db:"author,required"`
+		Asset  `db:"asset"`
+	}
+	// Post columns: (author asset.title asset.details.active)
+
+	post := Post{
+		Author: "Joe",
+		Asset:  Asset{Title: "Hello", Details: Details{Active: true}},
+	}
+	pv := reflect.ValueOf(post)
+
+	v := m.FieldByName(pv, "author")
+	if v.Interface().(string) != post.Author {
+		t.Errorf("Expecting %s, got %s", post.Author, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "title")
+	if _, ok := v.Interface().(string); ok {
+		t.Errorf("Expecting field to not exist")
+	}
+	v = m.FieldByName(pv, "asset.title")
+	if v.Interface().(string) != post.Asset.Title {
+		t.Errorf("Expecting %s, got %s", post.Asset.Title, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "asset.details.active")
+	if v.Interface().(bool) != post.Asset.Details.Active {
+		t.Errorf("Expecting %v, got %v", post.Asset.Details.Active, v.Interface().(bool))
+	}
+}
+
+func TestInlineStruct(t *testing.T) {
+	m := NewMapperTagFunc("db", strings.ToLower, nil)
+
+	type Employee struct {
+		Name string
+		ID   int
+	}
+	type Boss Employee
+	type person struct {
+		Employee `db:"employee"`
+		Boss     `db:"boss"`
+	}
+	// employees columns: (employee.name employee.id boss.name boss.id)
+
+	em := person{Employee: Employee{Name: "Joe", ID: 2}, Boss: Boss{Name: "Dick", ID: 1}}
+	ev := reflect.ValueOf(em)
+
+	fields := m.TypeMap(reflect.TypeOf(em))
+	if len(fields.Index) != 6 {
+		t.Errorf("Expecting 6 fields")
+	}
+
+	v := m.FieldByName(ev, "employee.name")
+	if v.Interface().(string) != em.Employee.Name {
+		t.Errorf("Expecting %s, got %s", em.Employee.Name, v.Interface().(string))
+	}
+	v = m.FieldByName(ev, "boss.id")
+	if ival(v) != em.Boss.ID {
+		t.Errorf("Expecting %v, got %v", em.Boss.ID, ival(v))
+	}
+}
+
+func TestFieldsEmbedded(t *testing.T) {
+	m := NewMapper("db")
+
+	type Person struct {
+		Name string `db:"name"`
+	}
+	type Place struct {
+		Name string `db:"name"`
+	}
+	type Article struct {
+		Title string `db:"title"`
+	}
+	type PP struct {
+		Person  `db:"person,required"`
+		Place   `db:",someflag"`
+		Article `db:",required"`
+	}
+	// PP columns: (person.name name title)
+
+	pp := PP{}
+	pp.Person.Name = "Peter"
+	pp.Place.Name = "Toronto"
+	pp.Article.Title = "Best city ever"
+
+	fields := m.TypeMap(reflect.TypeOf(pp))
+	// for i, f := range fields {
+	// 	log.Println(i, f)
+	// }
+
+	ppv := reflect.ValueOf(pp)
+
+	v := m.FieldByName(ppv, "person.name")
+	if v.Interface().(string) != pp.Person.Name {
+		t.Errorf("Expecting %s, got %s", pp.Person.Name, v.Interface().(string))
+	}
+
+	v = m.FieldByName(ppv, "name")
+	if v.Interface().(string) != pp.Place.Name {
+		t.Errorf("Expecting %s, got %s", pp.Place.Name, v.Interface().(string))
+	}
+
+	v = m.FieldByName(ppv, "title")
+	if v.Interface().(string) != pp.Article.Title {
+		t.Errorf("Expecting %s, got %s", pp.Article.Title, v.Interface().(string))
+	}
+
+	fi := fields.GetByPath("person")
+	if _, ok := fi.Options["required"]; !ok {
+		t.Errorf("Expecting required option to be set")
+	}
+	if !fi.Embedded {
+		t.Errorf("Expecting field to be embedded")
+	}
+	if len(fi.Index) != 1 || fi.Index[0] != 0 {
+		t.Errorf("Expecting index to be [0]")
+	}
+
+	fi = fields.GetByPath("person.name")
+	if fi == nil {
+		t.Errorf("Expecting person.name to exist")
+	}
+	if fi.Path != "person.name" {
+		t.Errorf("Expecting %s, got %s", "person.name", fi.Path)
+	}
+
+	fi = fields.GetByTraversal([]int{1, 0})
+	if fi == nil {
+		t.Errorf("Expecting traveral to exist")
+	}
+	if fi.Path != "name" {
+		t.Errorf("Expecting %s, got %s", "name", fi.Path)
+	}
+
+	fi = fields.GetByTraversal([]int{2})
+	if fi == nil {
+		t.Errorf("Expecting traversal to exist")
+	}
+	if _, ok := fi.Options["required"]; !ok {
+		t.Errorf("Expecting required option to be set")
+	}
+
+	trs := m.TraversalsByName(reflect.TypeOf(pp), []string{"person.name", "name", "title"})
+	if !reflect.DeepEqual(trs, [][]int{{0, 0}, {1, 0}, {2, 0}}) {
+		t.Errorf("Expecting traversal: %v", trs)
+	}
+}
+
+func TestPtrFields(t *testing.T) {
+	m := NewMapperTagFunc("db", strings.ToLower, nil)
+	type Asset struct {
+		Title string
+	}
+	type Post struct {
+		*Asset `db:"asset"`
+		Author string
+	}
+
+	post := &Post{Author: "Joe", Asset: &Asset{Title: "Hiyo"}}
+	pv := reflect.ValueOf(post)
+
+	fields := m.TypeMap(reflect.TypeOf(post))
+	if len(fields.Index) != 3 {
+		t.Errorf("Expecting 3 fields")
+	}
+
+	v := m.FieldByName(pv, "asset.title")
+	if v.Interface().(string) != post.Asset.Title {
+		t.Errorf("Expecting %s, got %s", post.Asset.Title, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "author")
+	if v.Interface().(string) != post.Author {
+		t.Errorf("Expecting %s, got %s", post.Author, v.Interface().(string))
+	}
+}
+
+func TestNamedPtrFields(t *testing.T) {
+	m := NewMapperTagFunc("db", strings.ToLower, nil)
+
+	type User struct {
+		Name string
+	}
+
+	type Asset struct {
+		Title string
+
+		Owner *User `db:"owner"`
+	}
+	type Post struct {
+		Author string
+
+		Asset1 *Asset `db:"asset1"`
+		Asset2 *Asset `db:"asset2"`
+	}
+
+	post := &Post{Author: "Joe", Asset1: &Asset{Title: "Hiyo", Owner: &User{"Username"}}} // Let Asset2 be nil
+	pv := reflect.ValueOf(post)
+
+	fields := m.TypeMap(reflect.TypeOf(post))
+	if len(fields.Index) != 9 {
+		t.Errorf("Expecting 9 fields")
+	}
+
+	v := m.FieldByName(pv, "asset1.title")
+	if v.Interface().(string) != post.Asset1.Title {
+		t.Errorf("Expecting %s, got %s", post.Asset1.Title, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "asset1.owner.name")
+	if v.Interface().(string) != post.Asset1.Owner.Name {
+		t.Errorf("Expecting %s, got %s", post.Asset1.Owner.Name, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "asset2.title")
+	if v.Interface().(string) != post.Asset2.Title {
+		t.Errorf("Expecting %s, got %s", post.Asset2.Title, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "asset2.owner.name")
+	if v.Interface().(string) != post.Asset2.Owner.Name {
+		t.Errorf("Expecting %s, got %s", post.Asset2.Owner.Name, v.Interface().(string))
+	}
+	v = m.FieldByName(pv, "author")
+	if v.Interface().(string) != post.Author {
+		t.Errorf("Expecting %s, got %s", post.Author, v.Interface().(string))
+	}
+}
+
+func TestFieldMap(t *testing.T) {
+	type Foo struct {
+		A int
+		B int
+		C int
+	}
+
+	f := Foo{1, 2, 3}
+	m := NewMapperFunc("db", strings.ToLower)
+
+	fm := m.FieldMap(reflect.ValueOf(f))
+
+	if len(fm) != 3 {
+		t.Errorf("Expecting %d keys, got %d", 3, len(fm))
+	}
+	if fm["a"].Interface().(int) != 1 {
+		t.Errorf("Expecting %d, got %d", 1, ival(fm["a"]))
+	}
+	if fm["b"].Interface().(int) != 2 {
+		t.Errorf("Expecting %d, got %d", 2, ival(fm["b"]))
+	}
+	if fm["c"].Interface().(int) != 3 {
+		t.Errorf("Expecting %d, got %d", 3, ival(fm["c"]))
+	}
+}
+
+func TestTagNameMapping(t *testing.T) {
+	type Strategy struct {
+		StrategyID   string `protobuf:"bytes,1,opt,name=strategy_id" json:"strategy_id,omitempty"`
+		StrategyName string
+	}
+
+	m := NewMapperTagFunc("json", strings.ToUpper, func(value string) string {
+		if strings.Contains(value, ",") {
+			return strings.Split(value, ",")[0]
+		}
+		return value
+	})
+	strategy := Strategy{"1", "Alpah"}
+	mapping := m.TypeMap(reflect.TypeOf(strategy))
+
+	for _, key := range []string{"strategy_id", "STRATEGYNAME"} {
+		if fi := mapping.GetByPath(key); fi == nil {
+			t.Errorf("Expecting to find key %s in mapping but did not.", key)
+		}
+	}
+}
+
+func TestMapping(t *testing.T) {
+	type Person struct {
+		ID           int
+		Name         string
+		WearsGlasses bool `db:"wears_glasses"`
+	}
+
+	m := NewMapperFunc("db", strings.ToLower)
+	p := Person{1, "Jason", true}
+	mapping := m.TypeMap(reflect.TypeOf(p))
+
+	for _, key := range []string{"id", "name", "wears_glasses"} {
+		if fi := mapping.GetByPath(key); fi == nil {
+			t.Errorf("Expecting to find key %s in mapping but did not.", key)
+		}
+	}
+
+	type SportsPerson struct {
+		Weight int
+		Age    int
+		Person
+	}
+	s := SportsPerson{Weight: 100, Age: 30, Person: p}
+	mapping = m.TypeMap(reflect.TypeOf(s))
+	for _, key := range []string{"id", "name", "wears_glasses", "weight", "age"} {
+		if fi := mapping.GetByPath(key); fi == nil {
+			t.Errorf("Expecting to find key %s in mapping but did not.", key)
+		}
+	}
+
+	type RugbyPlayer struct {
+		Position   int
+		IsIntense  bool `db:"is_intense"`
+		IsAllBlack bool `db:"-"`
+		SportsPerson
+	}
+	r := RugbyPlayer{12, true, false, s}
+	mapping = m.TypeMap(reflect.TypeOf(r))
+	for _, key := range []string{"id", "name", "wears_glasses", "weight", "age", "position", "is_intense"} {
+		if fi := mapping.GetByPath(key); fi == nil {
+			t.Errorf("Expecting to find key %s in mapping but did not.", key)
+		}
+	}
+
+	if fi := mapping.GetByPath("isallblack"); fi != nil {
+		t.Errorf("Expecting to ignore `IsAllBlack` field")
+	}
+}
+
+type E1 struct {
+	A int
+}
+type E2 struct {
+	E1
+	B int
+}
+type E3 struct {
+	E2
+	C int
+}
+type E4 struct {
+	E3
+	D int
+}
+
+func BenchmarkFieldNameL1(b *testing.B) {
+	e4 := E4{D: 1}
+	for i := 0; i < b.N; i++ {
+		v := reflect.ValueOf(e4)
+		f := v.FieldByName("D")
+		if f.Interface().(int) != 1 {
+			b.Fatal("Wrong value.")
+		}
+	}
+}
+
+func BenchmarkFieldNameL4(b *testing.B) {
+	e4 := E4{}
+	e4.A = 1
+	for i := 0; i < b.N; i++ {
+		v := reflect.ValueOf(e4)
+		f := v.FieldByName("A")
+		if f.Interface().(int) != 1 {
+			b.Fatal("Wrong value.")
+		}
+	}
+}
+
+func BenchmarkFieldPosL1(b *testing.B) {
+	e4 := E4{D: 1}
+	for i := 0; i < b.N; i++ {
+		v := reflect.ValueOf(e4)
+		f := v.Field(1)
+		if f.Interface().(int) != 1 {
+			b.Fatal("Wrong value.")
+		}
+	}
+}
+
+func BenchmarkFieldPosL4(b *testing.B) {
+	e4 := E4{}
+	e4.A = 1
+	for i := 0; i < b.N; i++ {
+		v := reflect.ValueOf(e4)
+		f := v.Field(0)
+		f = f.Field(0)
+		f = f.Field(0)
+		f = f.Field(0)
+		if f.Interface().(int) != 1 {
+			b.Fatal("Wrong value.")
+		}
+	}
+}
+
+func BenchmarkFieldByIndexL4(b *testing.B) {
+	e4 := E4{}
+	e4.A = 1
+	idx := []int{0, 0, 0, 0}
+	for i := 0; i < b.N; i++ {
+		v := reflect.ValueOf(e4)
+		f := FieldByIndexes(v, idx)
+		if f.Interface().(int) != 1 {
+			b.Fatal("Wrong value.")
+		}
+	}
+}