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tea/env.go

234 lines
4.9 KiB
Go

package tea
import (
"bytes"
"fmt"
"reflect"
"sort"
"strings"
)
type env struct {
data map[string]interface{}
parent *env
}
func (e *env) String() string {
var buf bytes.Buffer
e.pretty(&buf)
return buf.String()
}
func (e *env) pretty(buf *bytes.Buffer) {
if e.parent != nil {
e.parent.pretty(buf)
buf.WriteRune(' ')
}
var parts []string
for k, v := range e.data {
if s, ok := v.(string); ok {
parts = append(parts, fmt.Sprintf("[%s=%q]", k, s))
} else {
parts = append(parts, fmt.Sprintf("[%s=%v]", k, v))
}
}
sort.Strings(parts)
fmt.Fprintf(buf, "{%s}", strings.Join(parts, ", "))
}
func mkenv(test Test) *env {
var e *env
return e.save(test)
}
// save looks at the Test t and saves the values of its fields marked with a
// save tag. All of the fields for that tests are stored together as a data
// layer.
func (e *env) save(test Test) *env {
V := reflect.ValueOf(test)
if V.Type().Kind() == reflect.Ptr {
V = V.Elem()
}
T := V.Type()
if T.Kind() != reflect.Struct {
return e
}
saved := make(map[string]interface{})
for i := 0; i < T.NumField(); i++ {
f := T.Field(i)
if !isSaveField(f) {
continue
}
fv := V.Field(i)
saved[f.Name] = fv.Interface()
}
if len(saved) > 0 {
return &env{
data: saved,
parent: e,
}
}
return e
}
func (e *env) load(dest Test) error {
destV := reflect.ValueOf(dest).Elem()
destT := destV.Type()
e, err := e.match(dest)
if err != nil {
return fmt.Errorf("match failed: %w", err)
}
for i := 0; i < destT.NumField(); i++ {
f := destT.Field(i)
if !isLoadField(f) {
continue
}
fv := destV.Field(i)
if !fv.IsZero() {
// the value is already populated, so we don't want to overwrite
// it.
continue
}
set := false
for e := e; e != nil; e = e.parent {
v, ok := e.data[f.Name]
if !ok {
continue
}
ev := reflect.ValueOf(v)
if ev.Type().AssignableTo(fv.Type()) {
set = true
fv.Set(ev)
break
}
}
if !set {
return fmt.Errorf("%w: failed to set required field: %q", PlanError, f.Name)
}
}
return nil
}
func (e *env) match(dest Test) (*env, error) {
destV := reflect.ValueOf(dest).Elem()
destT := destV.Type()
required := getMatchFields(destT)
if len(required) == 0 {
return e, nil
}
var (
last *env
leaf *env
foundWithWrongType = make(map[string]bool)
foundWithMatchingType = make(map[string]bool)
foundWithWrongValue = make(map[string]bool)
foundWithCorrectValue = make(map[string]bool)
)
keep := func(v *env) {
if leaf == nil {
leaf = &env{data: v.data}
last = leaf
} else {
next := &env{data: v.data, parent: last}
last = next
}
}
for e := e; e != nil; e = e.parent {
present := make([]reflect.StructField, 0, len(required))
for _, f := range required {
ev, ok := e.data[f.Name]
if !ok {
break
}
if reflect.TypeOf(ev).AssignableTo(f.Type) {
foundWithMatchingType[f.Name] = true
present = append(present, f)
} else {
foundWithWrongType[f.Name] = true
}
}
// all required fields are present in this layer
if len(present) == len(required) {
// check that the values in the env match the values that were
// asked for.
matched := make(map[string]interface{})
wrongVal := make(map[string]bool)
for _, f := range required {
fv := destV.FieldByName(f.Name)
if fv.Interface() == e.data[f.Name] {
foundWithCorrectValue[f.Name] = true
matched[f.Name] = e.data[f.Name]
} else {
foundWithWrongValue[f.Name] = true
wrongVal[f.Name] = true
}
}
if len(wrongVal) > 0 {
continue
}
// all required match conditions are met
if len(matched) == len(required) {
keep(e)
}
} else {
// the required fields do not exist in the layer, so this layer
// does not conflict with the match requirement.
if leaf != nil {
// since we have a leaf node, we have already found a matching
// layer, and since this layer does not conflict, we keep it.
keep(e)
}
}
}
if leaf == nil {
var notFound []string
for _, f := range required {
if !foundWithMatchingType[f.Name] && !foundWithWrongType[f.Name] {
notFound = append(notFound, f.Name)
}
}
switch len(notFound) {
case 0:
break
case 1:
return nil, fmt.Errorf("%w: missing required field: %q", PlanError, notFound[0])
default:
return nil, fmt.Errorf("%w: missing %d required fields: %s", PlanError, len(notFound), notFound)
}
for f, _ := range foundWithWrongType {
if !foundWithMatchingType[f] {
return nil, fmt.Errorf("%w: field %s was only found with unmatching types", PlanError, f)
}
}
for f, _ := range foundWithWrongValue {
if !foundWithCorrectValue[f] {
return nil, fmt.Errorf("%w: field %s was only found with unmatching values", RunError, f)
}
}
return nil, fmt.Errorf("%w: required match fields not encountered on the same layer", PlanError)
}
return leaf, nil
}