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still moving codebase to new API (WIP)

This commit is contained in:
Harvey Kandola 2017-07-26 20:03:23 +01:00
parent 72b14def6d
commit d90b3249c3
44 changed files with 5276 additions and 336 deletions

View file

@ -12,6 +12,6 @@ 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.
tags in the ways that are vital to most marshallers, and they are slow.
This reflectx package extends reflect to achieve these goals.

View file

@ -1,5 +1,5 @@
// Package reflectx implements extensions to the standard reflect lib suitable
// for implementing marshaling and unmarshaling packages. The main Mapper type
// for implementing marshalling and unmarshalling 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.
@ -7,14 +7,13 @@
package reflectx
import (
"fmt"
"reflect"
"runtime"
"strings"
"sync"
)
// A FieldInfo is a collection of metadata about a struct field.
// A FieldInfo is metadata for a struct field.
type FieldInfo struct {
Index []int
Path string
@ -41,7 +40,8 @@ func (f StructMap) GetByPath(path string) *FieldInfo {
}
// GetByTraversal returns a *FieldInfo for a given integer path. It is
// analogous to reflect.FieldByIndex.
// analogous to reflect.FieldByIndex, but using the cached traversal
// rather than re-executing the reflect machinery each time.
func (f StructMap) GetByTraversal(index []int) *FieldInfo {
if len(index) == 0 {
return nil
@ -58,8 +58,8 @@ func (f StructMap) GetByTraversal(index []int) *FieldInfo {
}
// 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.
// behaves like most marshallers in the standard library, obeying a field tag
// for name mapping but also providing a basic transform function.
type Mapper struct {
cache map[reflect.Type]*StructMap
tagName string
@ -68,8 +68,8 @@ type Mapper struct {
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.
// NewMapper returns a new mapper using the tagName as its struct field tag.
// If tagName is the empty string, it is ignored.
func NewMapper(tagName string) *Mapper {
return &Mapper{
cache: make(map[reflect.Type]*StructMap),
@ -127,7 +127,7 @@ func (m *Mapper) FieldMap(v reflect.Value) map[string]reflect.Value {
return r
}
// FieldByName returns a field by the its mapped name as a reflect.Value.
// FieldByName returns a field by 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 {
@ -182,11 +182,12 @@ func (m *Mapper) TraversalsByName(t reflect.Type, names []string) [][]int {
return r
}
// FieldByIndexes returns a value for a particular struct traversal.
// FieldByIndexes returns a value for the field given by the struct traversal
// for the given value.
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 this is a pointer and it's nil, allocate a new value and set it
if v.Kind() == reflect.Ptr && v.IsNil() {
alloc := reflect.New(Deref(v.Type()))
v.Set(alloc)
@ -225,13 +226,12 @@ type kinder interface {
// 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 {
if k := v.Kind(); k != expected {
panic(&reflect.ValueError{Method: methodName(), Kind: k})
}
}
// methodName is returns the caller of the function calling methodName
// methodName returns the caller of the function calling methodName
func methodName() string {
pc, _, _, _ := runtime.Caller(2)
f := runtime.FuncForPC(pc)
@ -257,19 +257,92 @@ func apnd(is []int, i int) []int {
return x
}
type mapf func(string) string
// parseName parses the tag and the target name for the given field using
// the tagName (eg 'json' for `json:"foo"` tags), mapFunc for mapping the
// field's name to a target name, and tagMapFunc for mapping the tag to
// a target name.
func parseName(field reflect.StructField, tagName string, mapFunc, tagMapFunc mapf) (tag, fieldName string) {
// first, set the fieldName to the field's name
fieldName = field.Name
// if a mapFunc is set, use that to override the fieldName
if mapFunc != nil {
fieldName = mapFunc(fieldName)
}
// if there's no tag to look for, return the field name
if tagName == "" {
return "", fieldName
}
// if this tag is not set using the normal convention in the tag,
// then return the fieldname.. this check is done because according
// to the reflect documentation:
// If the tag does not have the conventional format,
// the value returned by Get is unspecified.
// which doesn't sound great.
if !strings.Contains(string(field.Tag), tagName+":") {
return "", fieldName
}
// at this point we're fairly sure that we have a tag, so lets pull it out
tag = field.Tag.Get(tagName)
// if we have a mapper function, call it on the whole tag
// XXX: this is a change from the old version, which pulled out the name
// before the tagMapFunc could be run, but I think this is the right way
if tagMapFunc != nil {
tag = tagMapFunc(tag)
}
// finally, split the options from the name
parts := strings.Split(tag, ",")
fieldName = parts[0]
return tag, fieldName
}
// parseOptions parses options out of a tag string, skipping the name
func parseOptions(tag string) map[string]string {
parts := strings.Split(tag, ",")
options := make(map[string]string, len(parts))
if len(parts) > 1 {
for _, opt := range parts[1:] {
// short circuit potentially expensive split op
if strings.Contains(opt, "=") {
kv := strings.Split(opt, "=")
options[kv[0]] = kv[1]
continue
}
options[opt] = ""
}
}
return options
}
// 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 {
func getMapping(t reflect.Type, tagName string, mapFunc, tagMapFunc mapf) *StructMap {
m := []*FieldInfo{}
root := &FieldInfo{}
queue := []typeQueue{}
queue = append(queue, typeQueue{Deref(t), root, ""})
QueueLoop:
for len(queue) != 0 {
// pop the first item off of the queue
tq := queue[0]
queue = queue[1:]
// ignore recursive field
for p := tq.fi.Parent; p != nil; p = p.Parent {
if tq.fi.Field.Type == p.Field.Type {
continue QueueLoop
}
}
nChildren := 0
if tq.t.Kind() == reflect.Struct {
nChildren = tq.t.NumField()
@ -278,53 +351,31 @@ func getMapping(t reflect.Type, tagName string, mapFunc, tagMapFunc func(string)
// 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)
}
// parse the tag and the target name using the mapping options for this field
tag, name := parseName(f, tagName, mapFunc, tagMapFunc)
// if the name is "-", disabled via a tag, skip it
if name == "-" {
continue
}
fi := FieldInfo{
Field: f,
Name: name,
Zero: reflect.New(f.Type).Elem(),
Options: parseOptions(tag),
}
// if the path is empty this path is just the name
if tq.pp == "" {
fi.Path = fi.Name
} else {
fi.Path = tq.pp + "." + fi.Name
}
// skip unexported fields
if len(f.PkgPath) != 0 && !f.Anonymous {
continue

View file

@ -247,11 +247,20 @@ func TestInlineStruct(t *testing.T) {
}
}
func TestRecursiveStruct(t *testing.T) {
type Person struct {
Parent *Person
}
m := NewMapperFunc("db", strings.ToLower)
var p *Person
m.TypeMap(reflect.TypeOf(p))
}
func TestFieldsEmbedded(t *testing.T) {
m := NewMapper("db")
type Person struct {
Name string `db:"name"`
Name string `db:"name,size=64"`
}
type Place struct {
Name string `db:"name"`
@ -311,6 +320,9 @@ func TestFieldsEmbedded(t *testing.T) {
if fi.Path != "person.name" {
t.Errorf("Expecting %s, got %s", "person.name", fi.Path)
}
if fi.Options["size"] != "64" {
t.Errorf("Expecting %s, got %s", "64", fi.Options["size"])
}
fi = fields.GetByTraversal([]int{1, 0})
if fi == nil {
@ -508,6 +520,312 @@ func TestMapping(t *testing.T) {
}
}
func TestGetByTraversal(t *testing.T) {
type C struct {
C0 int
C1 int
}
type B struct {
B0 string
B1 *C
}
type A struct {
A0 int
A1 B
}
testCases := []struct {
Index []int
ExpectedName string
ExpectNil bool
}{
{
Index: []int{0},
ExpectedName: "A0",
},
{
Index: []int{1, 0},
ExpectedName: "B0",
},
{
Index: []int{1, 1, 1},
ExpectedName: "C1",
},
{
Index: []int{3, 4, 5},
ExpectNil: true,
},
{
Index: []int{},
ExpectNil: true,
},
{
Index: nil,
ExpectNil: true,
},
}
m := NewMapperFunc("db", func(n string) string { return n })
tm := m.TypeMap(reflect.TypeOf(A{}))
for i, tc := range testCases {
fi := tm.GetByTraversal(tc.Index)
if tc.ExpectNil {
if fi != nil {
t.Errorf("%d: expected nil, got %v", i, fi)
}
continue
}
if fi == nil {
t.Errorf("%d: expected %s, got nil", i, tc.ExpectedName)
continue
}
if fi.Name != tc.ExpectedName {
t.Errorf("%d: expected %s, got %s", i, tc.ExpectedName, fi.Name)
}
}
}
// TestMapperMethodsByName tests Mapper methods FieldByName and TraversalsByName
func TestMapperMethodsByName(t *testing.T) {
type C struct {
C0 string
C1 int
}
type B struct {
B0 *C `db:"B0"`
B1 C `db:"B1"`
B2 string `db:"B2"`
}
type A struct {
A0 *B `db:"A0"`
B `db:"A1"`
A2 int
a3 int
}
val := &A{
A0: &B{
B0: &C{C0: "0", C1: 1},
B1: C{C0: "2", C1: 3},
B2: "4",
},
B: B{
B0: nil,
B1: C{C0: "5", C1: 6},
B2: "7",
},
A2: 8,
}
testCases := []struct {
Name string
ExpectInvalid bool
ExpectedValue interface{}
ExpectedIndexes []int
}{
{
Name: "A0.B0.C0",
ExpectedValue: "0",
ExpectedIndexes: []int{0, 0, 0},
},
{
Name: "A0.B0.C1",
ExpectedValue: 1,
ExpectedIndexes: []int{0, 0, 1},
},
{
Name: "A0.B1.C0",
ExpectedValue: "2",
ExpectedIndexes: []int{0, 1, 0},
},
{
Name: "A0.B1.C1",
ExpectedValue: 3,
ExpectedIndexes: []int{0, 1, 1},
},
{
Name: "A0.B2",
ExpectedValue: "4",
ExpectedIndexes: []int{0, 2},
},
{
Name: "A1.B0.C0",
ExpectedValue: "",
ExpectedIndexes: []int{1, 0, 0},
},
{
Name: "A1.B0.C1",
ExpectedValue: 0,
ExpectedIndexes: []int{1, 0, 1},
},
{
Name: "A1.B1.C0",
ExpectedValue: "5",
ExpectedIndexes: []int{1, 1, 0},
},
{
Name: "A1.B1.C1",
ExpectedValue: 6,
ExpectedIndexes: []int{1, 1, 1},
},
{
Name: "A1.B2",
ExpectedValue: "7",
ExpectedIndexes: []int{1, 2},
},
{
Name: "A2",
ExpectedValue: 8,
ExpectedIndexes: []int{2},
},
{
Name: "XYZ",
ExpectInvalid: true,
ExpectedIndexes: []int{},
},
{
Name: "a3",
ExpectInvalid: true,
ExpectedIndexes: []int{},
},
}
// build the names array from the test cases
names := make([]string, len(testCases))
for i, tc := range testCases {
names[i] = tc.Name
}
m := NewMapperFunc("db", func(n string) string { return n })
v := reflect.ValueOf(val)
values := m.FieldsByName(v, names)
if len(values) != len(testCases) {
t.Errorf("expected %d values, got %d", len(testCases), len(values))
t.FailNow()
}
indexes := m.TraversalsByName(v.Type(), names)
if len(indexes) != len(testCases) {
t.Errorf("expected %d traversals, got %d", len(testCases), len(indexes))
t.FailNow()
}
for i, val := range values {
tc := testCases[i]
traversal := indexes[i]
if !reflect.DeepEqual(tc.ExpectedIndexes, traversal) {
t.Errorf("expected %v, got %v", tc.ExpectedIndexes, traversal)
t.FailNow()
}
val = reflect.Indirect(val)
if tc.ExpectInvalid {
if val.IsValid() {
t.Errorf("%d: expected zero value, got %v", i, val)
}
continue
}
if !val.IsValid() {
t.Errorf("%d: expected valid value, got %v", i, val)
continue
}
actualValue := reflect.Indirect(val).Interface()
if !reflect.DeepEqual(tc.ExpectedValue, actualValue) {
t.Errorf("%d: expected %v, got %v", i, tc.ExpectedValue, actualValue)
}
}
}
func TestFieldByIndexes(t *testing.T) {
type C struct {
C0 bool
C1 string
C2 int
C3 map[string]int
}
type B struct {
B1 C
B2 *C
}
type A struct {
A1 B
A2 *B
}
testCases := []struct {
value interface{}
indexes []int
expectedValue interface{}
readOnly bool
}{
{
value: A{
A1: B{B1: C{C0: true}},
},
indexes: []int{0, 0, 0},
expectedValue: true,
readOnly: true,
},
{
value: A{
A2: &B{B2: &C{C1: "answer"}},
},
indexes: []int{1, 1, 1},
expectedValue: "answer",
readOnly: true,
},
{
value: &A{},
indexes: []int{1, 1, 3},
expectedValue: map[string]int{},
},
}
for i, tc := range testCases {
checkResults := func(v reflect.Value) {
if tc.expectedValue == nil {
if !v.IsNil() {
t.Errorf("%d: expected nil, actual %v", i, v.Interface())
}
} else {
if !reflect.DeepEqual(tc.expectedValue, v.Interface()) {
t.Errorf("%d: expected %v, actual %v", i, tc.expectedValue, v.Interface())
}
}
}
checkResults(FieldByIndexes(reflect.ValueOf(tc.value), tc.indexes))
if tc.readOnly {
checkResults(FieldByIndexesReadOnly(reflect.ValueOf(tc.value), tc.indexes))
}
}
}
func TestMustBe(t *testing.T) {
typ := reflect.TypeOf(E1{})
mustBe(typ, reflect.Struct)
defer func() {
if r := recover(); r != nil {
valueErr, ok := r.(*reflect.ValueError)
if !ok {
t.Errorf("unexpected Method: %s", valueErr.Method)
t.Error("expected panic with *reflect.ValueError")
return
}
if valueErr.Method != "github.com/jmoiron/sqlx/reflectx.TestMustBe" {
}
if valueErr.Kind != reflect.String {
t.Errorf("unexpected Kind: %s", valueErr.Kind)
}
} else {
t.Error("expected panic")
}
}()
typ = reflect.TypeOf("string")
mustBe(typ, reflect.Struct)
t.Error("got here, didn't expect to")
}
type E1 struct {
A int
}