gozcl: ImpliedBodySchema derives a body schema from a Go struct
This commit is contained in:
Martin Atkins
parent
0612bb9843
commit
17cf497b6e
|
|
@ -0,0 +1,153 @@
|
|||
package gozcl
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"reflect"
|
||||
"sort"
|
||||
"strings"
|
||||
|
||||
"github.com/apparentlymart/go-zcl/zcl"
|
||||
)
|
||||
|
||||
// ImpliedBodySchema produces a zcl.BodySchema derived from the type of the
|
||||
// given value, which must be a struct value or a pointer to one. If an
|
||||
// inappropriate value is passed, this function will panic.
|
||||
//
|
||||
// The second return argument indicates whether the given struct includes
|
||||
// a "remain" field, and thus the returned schema is non-exhaustive.
|
||||
//
|
||||
// This uses the tags on the fields of the struct to discover how each
|
||||
// field's value should be expressed within configuration. If an invalid
|
||||
// mapping is attempted, this function will panic.
|
||||
func ImpliedBodySchema(val interface{}) (schema *zcl.BodySchema, partial bool) {
|
||||
ty := reflect.TypeOf(val)
|
||||
|
||||
if ty.Kind() == reflect.Ptr {
|
||||
ty = ty.Elem()
|
||||
}
|
||||
|
||||
if ty.Kind() != reflect.Struct {
|
||||
panic(fmt.Sprintf("given value must be struct, not %T", val))
|
||||
}
|
||||
|
||||
var attrSchemas []zcl.AttributeSchema
|
||||
var blockSchemas []zcl.BlockHeaderSchema
|
||||
|
||||
tags := getFieldTags(ty)
|
||||
|
||||
attrNames := make([]string, 0, len(tags.Attributes))
|
||||
for n := range tags.Attributes {
|
||||
attrNames = append(attrNames, n)
|
||||
}
|
||||
sort.Strings(attrNames)
|
||||
for _, n := range attrNames {
|
||||
idx := tags.Attributes[n]
|
||||
field := ty.Field(idx)
|
||||
attrSchemas = append(attrSchemas, zcl.AttributeSchema{
|
||||
Name: n,
|
||||
Required: field.Type.Kind() != reflect.Ptr,
|
||||
})
|
||||
}
|
||||
|
||||
blockNames := make([]string, 0, len(tags.Blocks))
|
||||
for n := range tags.Blocks {
|
||||
blockNames = append(blockNames, n)
|
||||
}
|
||||
sort.Strings(blockNames)
|
||||
for _, n := range blockNames {
|
||||
idx := tags.Blocks[n]
|
||||
field := ty.Field(idx)
|
||||
fty := field.Type
|
||||
if fty.Kind() == reflect.Slice {
|
||||
fty = fty.Elem()
|
||||
}
|
||||
if fty.Kind() == reflect.Ptr {
|
||||
fty = fty.Elem()
|
||||
}
|
||||
if fty.Kind() != reflect.Struct {
|
||||
panic(fmt.Sprintf(
|
||||
"zcl 'block' tag kind cannot be applied to %s field %s: struct required", field.Type.String(), field.Name,
|
||||
))
|
||||
}
|
||||
ftags := getFieldTags(fty)
|
||||
var labelNames []string
|
||||
if len(ftags.Labels) > 0 {
|
||||
labelNames = make([]string, len(ftags.Labels))
|
||||
for i, l := range ftags.Labels {
|
||||
labelNames[i] = l.Name
|
||||
}
|
||||
}
|
||||
|
||||
blockSchemas = append(blockSchemas, zcl.BlockHeaderSchema{
|
||||
Type: n,
|
||||
LabelNames: labelNames,
|
||||
})
|
||||
}
|
||||
|
||||
partial = tags.Remain != nil
|
||||
schema = &zcl.BodySchema{
|
||||
Attributes: attrSchemas,
|
||||
Blocks: blockSchemas,
|
||||
}
|
||||
return schema, partial
|
||||
}
|
||||
|
||||
type fieldTags struct {
|
||||
Attributes map[string]int
|
||||
Blocks map[string]int
|
||||
Labels []labelField
|
||||
Remain *int
|
||||
}
|
||||
|
||||
type labelField struct {
|
||||
FieldIndex int
|
||||
Name string
|
||||
}
|
||||
|
||||
func getFieldTags(ty reflect.Type) *fieldTags {
|
||||
ret := &fieldTags{
|
||||
Attributes: map[string]int{},
|
||||
Blocks: map[string]int{},
|
||||
}
|
||||
|
||||
ct := ty.NumField()
|
||||
for i := 0; i < ct; i++ {
|
||||
field := ty.Field(i)
|
||||
tag := field.Tag.Get("zcl")
|
||||
if tag == "" {
|
||||
continue
|
||||
}
|
||||
|
||||
comma := strings.Index(tag, ",")
|
||||
var name, kind string
|
||||
if comma != -1 {
|
||||
name = tag[:comma]
|
||||
kind = tag[comma+1:]
|
||||
} else {
|
||||
name = tag
|
||||
kind = "attr"
|
||||
}
|
||||
|
||||
switch kind {
|
||||
case "attr":
|
||||
ret.Attributes[name] = i
|
||||
case "block":
|
||||
ret.Blocks[name] = i
|
||||
case "label":
|
||||
ret.Labels = append(ret.Labels, labelField{
|
||||
FieldIndex: i,
|
||||
Name: name,
|
||||
})
|
||||
case "remain":
|
||||
if ret.Remain != nil {
|
||||
panic("only one 'remain' tag is permitted")
|
||||
}
|
||||
idx := i // copy, because this loop will continue assigning to i
|
||||
ret.Remain = &idx
|
||||
default:
|
||||
panic(fmt.Sprintf("invalid zcl field tag kind %q on %s %q", kind, field.Type.String(), field.Name))
|
||||
}
|
||||
}
|
||||
|
||||
return ret
|
||||
}
|
||||
|
|
@ -0,0 +1,202 @@
|
|||
package gozcl
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"reflect"
|
||||
"testing"
|
||||
|
||||
"github.com/apparentlymart/go-zcl/zcl"
|
||||
"github.com/davecgh/go-spew/spew"
|
||||
)
|
||||
|
||||
func TestImpliedBodySchema(t *testing.T) {
|
||||
tests := []struct {
|
||||
val interface{}
|
||||
wantSchema *zcl.BodySchema
|
||||
wantPartial bool
|
||||
}{
|
||||
{
|
||||
struct{}{},
|
||||
&zcl.BodySchema{},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Ignored bool
|
||||
}{},
|
||||
&zcl.BodySchema{},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Attr1 bool `zcl:"attr1"`
|
||||
Attr2 bool `zcl:"attr2"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Attributes: []zcl.AttributeSchema{
|
||||
{
|
||||
Name: "attr1",
|
||||
Required: true,
|
||||
},
|
||||
{
|
||||
Name: "attr2",
|
||||
Required: true,
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Attr *bool `zcl:"attr,attr"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Attributes: []zcl.AttributeSchema{
|
||||
{
|
||||
Name: "attr",
|
||||
Required: false,
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Thing struct{} `zcl:"thing,block"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Blocks: []zcl.BlockHeaderSchema{
|
||||
{
|
||||
Type: "thing",
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Thing struct {
|
||||
Type string `zcl:"type,label"`
|
||||
Name string `zcl:"name,label"`
|
||||
} `zcl:"thing,block"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Blocks: []zcl.BlockHeaderSchema{
|
||||
{
|
||||
Type: "thing",
|
||||
LabelNames: []string{"type", "name"},
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Thing []struct {
|
||||
Type string `zcl:"type,label"`
|
||||
Name string `zcl:"name,label"`
|
||||
} `zcl:"thing,block"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Blocks: []zcl.BlockHeaderSchema{
|
||||
{
|
||||
Type: "thing",
|
||||
LabelNames: []string{"type", "name"},
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Thing *struct {
|
||||
Type string `zcl:"type,label"`
|
||||
Name string `zcl:"name,label"`
|
||||
} `zcl:"thing,block"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Blocks: []zcl.BlockHeaderSchema{
|
||||
{
|
||||
Type: "thing",
|
||||
LabelNames: []string{"type", "name"},
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Thing struct {
|
||||
Name string `zcl:"name,label"`
|
||||
Something string `zcl:"something"`
|
||||
} `zcl:"thing,block"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Blocks: []zcl.BlockHeaderSchema{
|
||||
{
|
||||
Type: "thing",
|
||||
LabelNames: []string{"name"},
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Doodad string `zcl:"doodad"`
|
||||
Thing struct {
|
||||
Name string `zcl:"name,label"`
|
||||
} `zcl:"thing,block"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Attributes: []zcl.AttributeSchema{
|
||||
{
|
||||
Name: "doodad",
|
||||
Required: true,
|
||||
},
|
||||
},
|
||||
Blocks: []zcl.BlockHeaderSchema{
|
||||
{
|
||||
Type: "thing",
|
||||
LabelNames: []string{"name"},
|
||||
},
|
||||
},
|
||||
},
|
||||
false,
|
||||
},
|
||||
{
|
||||
struct {
|
||||
Doodad string `zcl:"doodad"`
|
||||
Config string `zcl:",remain"`
|
||||
}{},
|
||||
&zcl.BodySchema{
|
||||
Attributes: []zcl.AttributeSchema{
|
||||
{
|
||||
Name: "doodad",
|
||||
Required: true,
|
||||
},
|
||||
},
|
||||
},
|
||||
true,
|
||||
},
|
||||
}
|
||||
|
||||
for _, test := range tests {
|
||||
t.Run(fmt.Sprintf("%#v", test.val), func(t *testing.T) {
|
||||
schema, partial := ImpliedBodySchema(test.val)
|
||||
if !reflect.DeepEqual(schema, test.wantSchema) {
|
||||
t.Errorf(
|
||||
"wrong schema\ngot: %s\nwant: %s",
|
||||
spew.Sdump(schema), spew.Sdump(test.wantSchema),
|
||||
)
|
||||
}
|
||||
|
||||
if partial != test.wantPartial {
|
||||
t.Errorf(
|
||||
"wrong partial flag\ngot: %#v\nwant: %#v",
|
||||
partial, test.wantPartial,
|
||||
)
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue