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// Copyright 2019 CUE Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package openapi
import (
"fmt"
"math"
"path"
"regexp"
"sort"
"strconv"
"strings"
"cuelang.org/go/cue"
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/errors"
"cuelang.org/go/cue/token"
"cuelang.org/go/internal"
"cuelang.org/go/internal/core/adt"
)
type buildContext struct {
inst *cue.Instance
instExt *cue.Instance
refPrefix string
path []string
expandRefs bool
structural bool
exclusiveBool bool
nameFunc func(inst *cue.Instance, path []string) string
descFunc func(v cue.Value) string
fieldFilter *regexp.Regexp
evalDepth int // detect cycles when resolving references
schemas *OrderedMap
// Track external schemas.
externalRefs map[string]*externalType
}
type externalType struct {
ref string
inst *cue.Instance
path []string
value cue.Value
}
type oaSchema = OrderedMap
type typeFunc func(b *builder, a cue.Value)
func schemas(g *Generator, inst *cue.Instance) (schemas *ast.StructLit, err error) {
var fieldFilter *regexp.Regexp
if g.FieldFilter != "" {
fieldFilter, err = regexp.Compile(g.FieldFilter)
if err != nil {
return nil, errors.Newf(token.NoPos, "invalid field filter: %v", err)
}
// verify that certain elements are still passed.
for _, f := range strings.Split(
"version,title,allOf,anyOf,not,enum,Schema/properties,Schema/items"+
"nullable,type", ",") {
if fieldFilter.MatchString(f) {
return nil, errors.Newf(token.NoPos, "field filter may not exclude %q", f)
}
}
}
if g.Version == "" {
g.Version = "3.0.0"
}
c := buildContext{
inst: inst,
instExt: inst,
refPrefix: "components/schemas",
expandRefs: g.ExpandReferences,
structural: g.ExpandReferences,
nameFunc: g.ReferenceFunc,
descFunc: g.DescriptionFunc,
schemas: &OrderedMap{},
externalRefs: map[string]*externalType{},
fieldFilter: fieldFilter,
}
switch g.Version {
case "3.0.0":
c.exclusiveBool = true
case "3.1.0":
default:
return nil, errors.Newf(token.NoPos, "unsupported version %s", g.Version)
}
defer func() {
switch x := recover().(type) {
case nil:
case *openapiError:
err = x
default:
panic(x)
}
}()
// Although paths is empty for now, it makes it valid OpenAPI spec.
i, err := inst.Value().Fields(cue.Definitions(true))
if err != nil {
return nil, err
}
for i.Next() {
if !i.IsDefinition() {
continue
}
// message, enum, or constant.
label := i.Label()
if c.isInternal(label) {
continue
}
if i.IsDefinition() && strings.HasPrefix(label, "#") {
label = label[1:]
}
ref := c.makeRef(inst, []string{label})
if ref == "" {
continue
}
c.schemas.Set(ref, c.build(label, i.Value()))
}
// keep looping until a fixed point is reached.
for done := 0; len(c.externalRefs) != done; {
done = len(c.externalRefs)
// From now on, all references need to be expanded
external := []string{}
for k := range c.externalRefs {
external = append(external, k)
}
sort.Strings(external)
for _, k := range external {
ext := c.externalRefs[k]
c.instExt = ext.inst
last := len(ext.path) - 1
c.path = ext.path[:last]
name := ext.path[last]
c.schemas.Set(ext.ref, c.build(name, cue.Dereference(ext.value)))
}
}
a := c.schemas.Elts
sort.Slice(a, func(i, j int) bool {
x, _, _ := ast.LabelName(a[i].(*ast.Field).Label)
y, _, _ := ast.LabelName(a[j].(*ast.Field).Label)
return x < y
})
return (*ast.StructLit)(c.schemas), nil
}
func (c *buildContext) build(name string, v cue.Value) *ast.StructLit {
return newCoreBuilder(c).schema(nil, name, v)
}
// isInternal reports whether or not to include this type.
func (c *buildContext) isInternal(name string) bool {
// TODO: allow a regexp filter in Config. If we have closed structs and
// definitions, this will likely be unnecessary.
return strings.HasSuffix(name, "_value")
}
func (b *builder) failf(v cue.Value, format string, args ...interface{}) {
panic(&openapiError{
errors.NewMessage(format, args),
b.ctx.path,
v.Pos(),
})
}
func (b *builder) unsupported(v cue.Value) {
if b.format == "" {
// Not strictly an error, but consider listing it as a warning
// in strict mode.
}
}
func (b *builder) checkArgs(a []cue.Value, n int) {
if len(a)-1 != n {
b.failf(a[0], "%v must be used with %d arguments", a[0], len(a)-1)
}
}
func (b *builder) schema(core *builder, name string, v cue.Value) *ast.StructLit {
oldPath := b.ctx.path
b.ctx.path = append(b.ctx.path, name)
defer func() { b.ctx.path = oldPath }()
var c *builder
if core == nil && b.ctx.structural {
c = newCoreBuilder(b.ctx)
c.buildCore(v) // initialize core structure
c.coreSchema()
} else {
c = newRootBuilder(b.ctx)
c.core = core
}
return c.fillSchema(v)
}
func (b *builder) getDoc(v cue.Value) {
doc := []string{}
if b.ctx.descFunc != nil {
if str := b.ctx.descFunc(v); str != "" {
doc = append(doc, str)
}
} else {
for _, d := range v.Doc() {
doc = append(doc, d.Text())
}
}
if len(doc) > 0 {
str := strings.TrimSpace(strings.Join(doc, "\n\n"))
b.setSingle("description", ast.NewString(str), true)
}
}
func (b *builder) fillSchema(v cue.Value) *ast.StructLit {
if b.filled != nil {
return b.filled
}
b.setValueType(v)
b.format = extractFormat(v)
b.deprecated = getDeprecated(v)
if b.core == nil || len(b.core.values) > 1 {
isRef := b.value(v, nil)
if isRef {
b.typ = ""
}
if !isRef && !b.ctx.structural {
b.getDoc(v)
}
}
schema := b.finish()
s := (*ast.StructLit)(schema)
simplify(b, s)
sortSchema(s)
b.filled = s
return s
}
func label(d ast.Decl) string {
f := d.(*ast.Field)
s, _, _ := ast.LabelName(f.Label)
return s
}
func value(d ast.Decl) ast.Expr {
return d.(*ast.Field).Value
}
func sortSchema(s *ast.StructLit) {
sort.Slice(s.Elts, func(i, j int) bool {
iName := label(s.Elts[i])
jName := label(s.Elts[j])
pi := fieldOrder[iName]
pj := fieldOrder[jName]
if pi != pj {
return pi > pj
}
return iName < jName
})
}
var fieldOrder = map[string]int{
"description": 31,
"type": 30,
"format": 29,
"required": 28,
"properties": 27,
"minProperties": 26,
"maxProperties": 25,
"minimum": 24,
"exclusiveMinimum": 23,
"maximum": 22,
"exclusiveMaximum": 21,
"minItems": 18,
"maxItems": 17,
"minLength": 16,
"maxLength": 15,
"items": 14,
"enum": 13,
"default": 12,
}
func (b *builder) value(v cue.Value, f typeFunc) (isRef bool) {
count := 0
disallowDefault := false
var values cue.Value
if b.ctx.expandRefs || b.format != "" {
values = cue.Dereference(v)
count = 1
} else {
dedup := map[string]bool{}
hasNoRef := false
accept := v
conjuncts := appendSplit(nil, cue.AndOp, v)
for _, v := range conjuncts {
// This may be a reference to an enum. So we need to check references before
// dissecting them.
switch p, r := v.Reference(); {
case len(r) > 0:
ref := b.ctx.makeRef(p, r)
if ref == "" {
v = cue.Dereference(v)
break
}
if dedup[ref] {
continue
}
dedup[ref] = true
b.addRef(v, p, r)
disallowDefault = true
continue
}
hasNoRef = true
count++
values = values.UnifyAccept(v, accept)
}
isRef = !hasNoRef && len(dedup) == 1
}
if count > 0 { // TODO: implement IsAny.
// TODO: perhaps find optimal representation. For now we assume the
// representation as is is already optimized for human consumption.
if values.IncompleteKind()&cue.StructKind != cue.StructKind && !isRef {
values = values.Eval()
}
conjuncts := appendSplit(nil, cue.AndOp, values)
for i, v := range conjuncts {
switch {
case isConcrete(v):
b.dispatch(f, v)
if !b.isNonCore() {
b.set("enum", ast.NewList(b.decode(v)))
}
default:
a := appendSplit(nil, cue.OrOp, v)
for i, v := range a {
if _, r := v.Reference(); len(r) == 0 {
a[i] = v.Eval()
}
}
_ = i
// TODO: it matters here whether a conjunct is obtained
// from embedding or normal unification. Fix this at some
// point.
//
// if len(a) > 1 {
// // Filter disjuncts that cannot unify with other conjuncts,
// // and thus can never be satisfied.
// // TODO: there should be generalized simplification logic
// // in CUE (outside of the usual implicit simplifications).
// k := 0
// outer:
// for _, d := range a {
// for j, w := range conjuncts {
// if i == j {
// continue
// }
// if d.Unify(w).Err() != nil {
// continue outer
// }
// }
// a[k] = d
// k++
// }
// a = a[:k]
// }
switch len(a) {
case 0:
// Conjunct entirely eliminated.
case 1:
v = a[0]
if err := v.Err(); err != nil {
b.failf(v, "openapi: %v", err)
return
}
b.dispatch(f, v)
default:
b.disjunction(a, f)
}
}
}
}
if v, ok := v.Default(); ok && v.IsConcrete() && !disallowDefault {
// TODO: should we show the empty list default? This would be correct
// but perhaps a bit too pedantic and noisy.
switch {
case v.Kind() == cue.ListKind:
iter, _ := v.List()
if !iter.Next() {
// Don't show default for empty list.
break
}
fallthrough
default:
if !b.isNonCore() {
e := v.Syntax(cue.Concrete(true)).(ast.Expr)
b.setFilter("Schema", "default", e)
}
}
}
return isRef
}
func appendSplit(a []cue.Value, splitBy cue.Op, v cue.Value) []cue.Value {
op, args := v.Expr()
// dedup elements.
k := 1
outer:
for i := 1; i < len(args); i++ {
for j := 0; j < k; j++ {
if args[i].Subsume(args[j], cue.Raw()) == nil &&
args[j].Subsume(args[i], cue.Raw()) == nil {
continue outer
}
}
args[k] = args[i]
k++
}
args = args[:k]
if op == cue.NoOp && len(args) == 1 {
// TODO: this is to deal with default value removal. This may change
// whe we completely separate default values from values.
a = append(a, args...)
} else if op != splitBy {
a = append(a, v)
} else {
for _, v := range args {
a = appendSplit(a, splitBy, v)
}
}
return a
}
func countNodes(v cue.Value) (n int) {
switch op, a := v.Expr(); op {
case cue.OrOp, cue.AndOp:
for _, v := range a {
n += countNodes(v)
}
n += len(a) - 1
default:
switch v.Kind() {
case cue.ListKind:
for i, _ := v.List(); i.Next(); {
n += countNodes(i.Value())
}
case cue.StructKind:
for i, _ := v.Fields(); i.Next(); {
n += countNodes(i.Value()) + 1
}
}
}
return n + 1
}
// isConcrete reports whether v is concrete and not a struct (recursively).
// structs are not supported as the result of a struct enum depends on how
// conjunctions and disjunctions are distributed. We could consider still doing
// this if we define a normal form.
func isConcrete(v cue.Value) bool {
if !v.IsConcrete() {
return false
}
if v.Kind() == cue.StructKind {
return false // TODO: handle struct kinds
}
for list, _ := v.List(); list.Next(); {
if !isConcrete(list.Value()) {
return false
}
}
return true
}
func (b *builder) disjunction(a []cue.Value, f typeFunc) {
disjuncts := []cue.Value{}
enums := []ast.Expr{} // TODO: unique the enums
nullable := false // Only supported in OpenAPI, not JSON schema
for _, v := range a {
switch {
case v.Null() == nil:
// TODO: for JSON schema, we need to fall through.
nullable = true
case isConcrete(v):
enums = append(enums, b.decode(v))
default:
disjuncts = append(disjuncts, v)
}
}
// Only one conjunct?
if len(disjuncts) == 0 || (len(disjuncts) == 1 && len(enums) == 0) {
if len(disjuncts) == 1 {
b.value(disjuncts[0], f)
}
if len(enums) > 0 && !b.isNonCore() {
b.set("enum", ast.NewList(enums...))
}
if nullable {
b.setSingle("nullable", ast.NewBool(true), true) // allowed in Structural
}
return
}
anyOf := []ast.Expr{}
if len(enums) > 0 {
anyOf = append(anyOf, b.kv("enum", ast.NewList(enums...)))
}
if nullable {
b.setSingle("nullable", ast.NewBool(true), true)
}
schemas := make([]*ast.StructLit, len(disjuncts))
for i, v := range disjuncts {
c := newOASBuilder(b)
c.value(v, f)
t := c.finish()
schemas[i] = (*ast.StructLit)(t)
if len(t.Elts) == 0 {
if c.typ == "" {
return
}
}
}
for i, v := range disjuncts {
// In OpenAPI schema are open by default. To ensure forward compatibility,
// we do not represent closed structs with additionalProperties: false
// (this is discouraged and often disallowed by implementions), but
// rather enforce this by ensuring uniqueness of the disjuncts.
//
// TODO: subsumption may currently give false negatives. We are extra
// conservative in these instances.
subsumed := []ast.Expr{}
for j, w := range disjuncts {
if i == j {
continue
}
err := v.Subsume(w, cue.Schema())
if err == nil || errors.Is(err, internal.ErrInexact) {
subsumed = append(subsumed, schemas[j])
}
}
t := schemas[i]
if len(subsumed) > 0 {
// TODO: elide anyOf if there is only one element. This should be
// rare if originating from oneOf.
exclude := ast.NewStruct("not",
ast.NewStruct("anyOf", ast.NewList(subsumed...)))
if len(t.Elts) == 0 {
t = exclude
} else {
t = ast.NewStruct("allOf", ast.NewList(t, exclude))
}
}
anyOf = append(anyOf, t)
}
b.set("oneOf", ast.NewList(anyOf...))
}
func (b *builder) setValueType(v cue.Value) {
if b.core != nil {
return
}
k := v.IncompleteKind() &^ adt.NullKind
switch k {
case cue.BoolKind:
b.typ = "boolean"
case cue.FloatKind, cue.NumberKind:
b.typ = "number"
case cue.IntKind:
b.typ = "integer"
case cue.BytesKind:
b.typ = "string"
case cue.StringKind:
b.typ = "string"
case cue.StructKind:
b.typ = "object"
case cue.ListKind:
b.typ = "array"
}
}
func (b *builder) dispatch(f typeFunc, v cue.Value) {
if f != nil {
f(b, v)
return
}
switch v.IncompleteKind() {
case cue.NullKind:
// TODO: for JSON schema we would set the type here. For OpenAPI,
// it must be nullable.
b.setSingle("nullable", ast.NewBool(true), true)
case cue.BoolKind:
b.setType("boolean", "")
// No need to call.
case cue.FloatKind, cue.NumberKind:
// TODO:
// Common Name type format Comments
// float number float
// double number double
b.setType("number", "") // may be overridden to integer
b.number(v)
case cue.IntKind:
// integer integer int32 signed 32 bits
// long integer int64 signed 64 bits
b.setType("integer", "") // may be overridden to integer
b.number(v)
// TODO: for JSON schema, consider adding multipleOf: 1.
case cue.BytesKind:
// byte string byte base64 encoded characters
// binary string binary any sequence of octets
b.setType("string", "byte")
b.bytes(v)
case cue.StringKind:
// date string date As defined by full-date - RFC3339
// dateTime string date-time As defined by date-time - RFC3339
// password string password A hint to UIs to obscure input
b.setType("string", "")
b.string(v)
case cue.StructKind:
b.setType("object", "")
b.object(v)
case cue.ListKind:
b.setType("array", "")
b.array(v)
}
}
// object supports the following
// - maxProperties: maximum allowed fields in this struct.
// - minProperties: minimum required fields in this struct.
// - patternProperties: [regexp]: schema
// TODO: we can support this once .kv(key, value) allow
// foo [=~"pattern"]: type
// An instance field must match all schemas for which a regexp matches.
// Even though it is not supported in OpenAPI, we should still accept it
// when receiving from OpenAPI. We could possibly use disjunctions to encode
// this.
// - dependencies: what?
// - propertyNames: schema
// every property name in the enclosed schema matches that of
func (b *builder) object(v cue.Value) {
// TODO: discriminator objects: we could theoretically derive discriminator
// objects automatically: for every object in a oneOf/allOf/anyOf, or any
// object composed of the same type, if a property is required and set to a
// constant value for each type, it is a discriminator.
switch op, a := v.Expr(); op {
case cue.CallOp:
name := fmt.Sprint(a[0])
switch name {
case "struct.MinFields":
b.checkArgs(a, 1)
b.setFilter("Schema", "minProperties", b.int(a[1]))
return
case "struct.MaxFields":
b.checkArgs(a, 1)
b.setFilter("Schema", "maxProperties", b.int(a[1]))
return
default:
b.unsupported(a[0])
return
}
case cue.NoOp:
// TODO: extract format from specific type.
default:
b.failf(v, "unsupported op %v for object type (%v)", op, v)
return
}
required := []ast.Expr{}
for i, _ := v.Fields(); i.Next(); {
required = append(required, ast.NewString(i.Label()))
}
if len(required) > 0 {
b.setFilter("Schema", "required", ast.NewList(required...))
}
var properties *OrderedMap
if b.singleFields != nil {
properties = b.singleFields.getMap("properties")
}
hasProps := properties != nil
if !hasProps {
properties = &OrderedMap{}
}
for i, _ := v.Fields(cue.Optional(true), cue.Definitions(true)); i.Next(); {
label := i.Label()
if b.ctx.isInternal(label) {
continue
}
if i.IsDefinition() && strings.HasPrefix(label, "#") {
label = label[1:]
}
var core *builder
if b.core != nil {
core = b.core.properties[label]
}
schema := b.schema(core, label, i.Value())
switch {
case i.IsDefinition():
ref := b.ctx.makeRef(b.ctx.instExt, append(b.ctx.path, label))
if ref == "" {
continue
}
b.ctx.schemas.Set(ref, schema)
case !b.isNonCore() || len(schema.Elts) > 0:
properties.Set(label, schema)
}
}
if !hasProps && properties.len() > 0 {
b.setSingle("properties", (*ast.StructLit)(properties), false)
}
if t, ok := v.Elem(); ok && (b.core == nil || b.core.items == nil) {
schema := b.schema(nil, "*", t)
if len(schema.Elts) > 0 {
b.setSingle("additionalProperties", schema, true) // Not allowed in structural.
}
}
// TODO: maxProperties, minProperties: can be done once we allow cap to
// unify with structs.
}
// List constraints:
//
// Max and min items.
// - maxItems: int (inclusive)
// - minItems: int (inclusive)
// - items (item type)
// schema: applies to all items
// array of schemas:
// schema at pos must match if both value and items are defined.
// - additional items:
// schema: where items must be an array of schemas, intstance elements
// succeed for if they match this value for any value at a position
// greater than that covered by items.
// - uniqueItems: bool
// TODO: support with list.Unique() unique() or comprehensions.
// For the latter, we need equality for all values, which is doable,
// but not done yet.
//
// NOT SUPPORTED IN OpenAPI:
// - contains:
// schema: an array instance is valid if at least one element matches
// this schema.
func (b *builder) array(v cue.Value) {
switch op, a := v.Expr(); op {
case cue.CallOp:
name := fmt.Sprint(a[0])
switch name {
case "list.UniqueItems", "list.UniqueItems()":
b.checkArgs(a, 0)
b.setFilter("Schema", "uniqueItems", ast.NewBool(true))
return
case "list.MinItems":
b.checkArgs(a, 1)
b.setFilter("Schema", "minItems", b.int(a[1]))
return
case "list.MaxItems":
b.checkArgs(a, 1)
b.setFilter("Schema", "maxItems", b.int(a[1]))
return
default:
b.unsupported(a[0])
return
}
case cue.NoOp:
// TODO: extract format from specific type.
default:
b.failf(v, "unsupported op %v for array type", op)
return
}
// Possible conjuncts:
// - one list (CUE guarantees merging all conjuncts)
// - no cap: is unified with list
// - unique items: at most one, but idempotent if multiple.
// There is never a need for allOf or anyOf. Note that a CUE list
// corresponds almost one-to-one to OpenAPI lists.
items := []ast.Expr{}
count := 0
for i, _ := v.List(); i.Next(); count++ {
items = append(items, b.schema(nil, strconv.Itoa(count), i.Value()))
}
if len(items) > 0 {
// TODO: per-item schema are not allowed in OpenAPI, only in JSON Schema.
// Perhaps we should turn this into an OR after first normalizing
// the entries.
b.set("items", ast.NewList(items...))
// panic("per-item types not supported in OpenAPI")
}
// TODO:
// A CUE cap can be a set of discontinuous ranges. If we encounter this,
// we can create an allOf(list type, anyOf(ranges)).
cap := v.Len()
hasMax := false
maxLength := int64(math.MaxInt64)
if n, capErr := cap.Int64(); capErr == nil {
maxLength = n
hasMax = true
} else {
b.value(cap, (*builder).listCap)
}
if !hasMax || int64(len(items)) < maxLength {
if typ, ok := v.Elem(); ok {
var core *builder
if b.core != nil {
core = b.core.items
}
t := b.schema(core, "*", typ)
if len(items) > 0 {
b.setFilter("Schema", "additionalItems", t) // Not allowed in structural.
} else if !b.isNonCore() || len(t.Elts) > 0 {
b.setSingle("items", t, true)
}
}
}
}
func (b *builder) listCap(v cue.Value) {
switch op, a := v.Expr(); op {
case cue.LessThanOp:
b.setFilter("Schema", "maxItems", b.inta(a[0], -1))
case cue.LessThanEqualOp:
b.setFilter("Schema", "maxItems", b.inta(a[0], 0))
case cue.GreaterThanOp:
b.setFilter("Schema", "minItems", b.inta(a[0], 1))
case cue.GreaterThanEqualOp:
if b.int64(a[0]) > 0 {
b.setFilter("Schema", "minItems", b.inta(a[0], 0))
}
case cue.NoOp:
// must be type, so okay.
case cue.NotEqualOp:
i := b.int(a[0])
b.setNot("allOff", ast.NewList(
b.kv("minItems", i),
b.kv("maxItems", i),
))
default:
b.failf(v, "unsupported op for list capacity %v", op)
return
}
}
func (b *builder) number(v cue.Value) {
// Multiple conjuncts mostly means just additive constraints.
// Type may be number of float.
switch op, a := v.Expr(); op {
case cue.LessThanOp:
if b.ctx.exclusiveBool {
b.setFilter("Schema", "exclusiveMaximum", ast.NewBool(true))
b.setFilter("Schema", "maximum", b.big(a[0]))
} else {
b.setFilter("Schema", "exclusiveMaximum", b.big(a[0]))
}
case cue.LessThanEqualOp:
b.setFilter("Schema", "maximum", b.big(a[0]))
case cue.GreaterThanOp:
if b.ctx.exclusiveBool {
b.setFilter("Schema", "exclusiveMinimum", ast.NewBool(true))
b.setFilter("Schema", "minimum", b.big(a[0]))
} else {
b.setFilter("Schema", "exclusiveMinimum", b.big(a[0]))
}
case cue.GreaterThanEqualOp:
b.setFilter("Schema", "minimum", b.big(a[0]))
case cue.NotEqualOp:
i := b.big(a[0])
b.setNot("allOff", ast.NewList(
b.kv("minimum", i),
b.kv("maximum", i),
))
case cue.CallOp:
name := fmt.Sprint(a[0])
switch name {
case "math.MultipleOf":
b.checkArgs(a, 1)
b.setFilter("Schema", "multipleOf", b.int(a[1]))
default:
b.unsupported(a[0])
return
}
case cue.NoOp:
// TODO: extract format from specific type.
default:
b.failf(v, "unsupported op for number %v", op)
}
}
// Multiple Regexp conjuncts are represented as allOf all other
// constraints can be combined unless in the even of discontinuous
// lengths.
// string supports the following options:
//
// - maxLength (Unicode codepoints)
// - minLength (Unicode codepoints)
// - pattern (a regexp)
//
// The regexp pattern is as follows, and is limited to be a strict subset of RE2:
// Ref: https://tools.ietf.org/html/draft-wright-json-schema-validation-01#section-3.3
//
// JSON schema requires ECMA 262 regular expressions, but
// limited to the following constructs:
// - simple character classes: [abc]
// - range character classes: [a-z]
// - complement character classes: [^abc], [^a-z]
// - simple quantifiers: +, *, ?, and lazy versions +? *? ??
// - range quantifiers: {x}, {x,y}, {x,}, {x}?, {x,y}?, {x,}?
// - begin and end anchors: ^ and $
// - simple grouping: (...)
// - alteration: |
// This is a subset of RE2 used by CUE.
//
// Most notably absent:
// - the '.' for any character (not sure if that is a doc bug)
// - character classes \d \D [[::]] \pN \p{Name} \PN \P{Name}
// - word boundaries
// - capturing directives.
// - flag setting
// - comments
//
// The capturing directives and comments can be removed without
// compromising the meaning of the regexp (TODO). Removing
// flag setting will be tricky. Unicode character classes,
// boundaries, etc can be compiled into simple character classes,
// although the resulting regexp will look cumbersome.
//
func (b *builder) string(v cue.Value) {
switch op, a := v.Expr(); op {
case cue.RegexMatchOp, cue.NotRegexMatchOp:
s, err := a[0].String()
if err != nil {
// TODO: this may be an unresolved interpolation or expression. Consider
// whether it is reasonable to treat unevaluated operands as wholes and
// generate a compound regular expression.
b.failf(v, "regexp value must be a string: %v", err)
return
}
if op == cue.RegexMatchOp {
b.setFilter("Schema", "pattern", ast.NewString(s))
} else {
b.setNot("pattern", ast.NewString(s))
}
case cue.NoOp, cue.SelectorOp:
case cue.CallOp:
name := fmt.Sprint(a[0])
switch name {
case "strings.MinRunes":
b.checkArgs(a, 1)
b.setFilter("Schema", "minLength", b.int(a[1]))
return
case "strings.MaxRunes":
b.checkArgs(a, 1)
b.setFilter("Schema", "maxLength", b.int(a[1]))
return
default:
b.unsupported(a[0])
return
}
default:
b.failf(v, "unsupported op %v for string type", op)
}
}
func (b *builder) bytes(v cue.Value) {
switch op, a := v.Expr(); op {
case cue.RegexMatchOp, cue.NotRegexMatchOp:
s, err := a[0].Bytes()
if err != nil {
// TODO: this may be an unresolved interpolation or expression. Consider
// whether it is reasonable to treat unevaluated operands as wholes and
// generate a compound regular expression.
b.failf(v, "regexp value must be of type bytes: %v", err)
return
}
e := ast.NewString(string(s))
if op == cue.RegexMatchOp {
b.setFilter("Schema", "pattern", e)
} else {
b.setNot("pattern", e)
}
// TODO: support the following JSON schema constraints
// - maxLength
// - minLength
case cue.NoOp, cue.SelectorOp:
default:
b.failf(v, "unsupported op %v for bytes type", op)
}
}
type builder struct {
ctx *buildContext
typ string
format string
singleFields *oaSchema
current *oaSchema
allOf []*ast.StructLit
deprecated bool
// Building structural schema
core *builder
kind cue.Kind
filled *ast.StructLit
values []cue.Value // in structural mode, all values of not and *Of.
keys []string
properties map[string]*builder
items *builder
}
func newRootBuilder(c *buildContext) *builder {
return &builder{ctx: c}
}
func newOASBuilder(parent *builder) *builder {
core := parent
if parent.core != nil {
core = parent.core
}
b := &builder{
core: core,
ctx: parent.ctx,
typ: parent.typ,
format: parent.format,
}
return b
}
func (b *builder) isNonCore() bool {
return b.core != nil
}
func (b *builder) setType(t, format string) {
if b.typ == "" {
b.typ = t
if format != "" {
b.format = format
}
}
}
func setType(t *oaSchema, b *builder) {
if b.typ != "" {
if b.core == nil || (b.core.typ != b.typ && !b.ctx.structural) {
if !t.exists("type") {
t.Set("type", ast.NewString(b.typ))
}
}
}
if b.format != "" {
if b.core == nil || b.core.format != b.format {
t.Set("format", ast.NewString(b.format))
}
}
}
// setFilter is like set, but allows the key-value pair to be filtered.
func (b *builder) setFilter(schema, key string, v ast.Expr) {
if re := b.ctx.fieldFilter; re != nil && re.MatchString(path.Join(schema, key)) {
return
}
b.set(key, v)
}
// setSingle sets a value of which there should only be one.
func (b *builder) setSingle(key string, v ast.Expr, drop bool) {
if b.singleFields == nil {
b.singleFields = &OrderedMap{}
}
if b.singleFields.exists(key) {
if !drop {
b.failf(cue.Value{}, "more than one value added for key %q", key)
}
}
b.singleFields.Set(key, v)
}
func (b *builder) set(key string, v ast.Expr) {
if b.current == nil {
b.current = &OrderedMap{}
b.allOf = append(b.allOf, (*ast.StructLit)(b.current))
} else if b.current.exists(key) {
b.current = &OrderedMap{}
b.allOf = append(b.allOf, (*ast.StructLit)(b.current))
}
b.current.Set(key, v)
}
func (b *builder) kv(key string, value ast.Expr) *ast.StructLit {
return ast.NewStruct(key, value)
}
func (b *builder) setNot(key string, value ast.Expr) {
b.add(ast.NewStruct("not", b.kv(key, value)))
}
func (b *builder) finish() *ast.StructLit {
var t *OrderedMap
if b.filled != nil {
return b.filled
}
switch len(b.allOf) {
case 0:
t = &OrderedMap{}
case 1:
hasRef := false
for _, e := range b.allOf[0].Elts {
if f, ok := e.(*ast.Field); ok {
name, _, _ := ast.LabelName(f.Label)
hasRef = hasRef || name == "$ref"
}
}
if !hasRef || b.singleFields == nil {
t = (*OrderedMap)(b.allOf[0])
break
}
fallthrough
default:
exprs := []ast.Expr{}
if t != nil {
exprs = append(exprs, (*ast.StructLit)(t))
}
for _, s := range b.allOf {
exprs = append(exprs, s)
}
t = &OrderedMap{}
t.Set("allOf", ast.NewList(exprs...))
}
if b.singleFields != nil {
b.singleFields.Elts = append(b.singleFields.Elts, t.Elts...)
t = b.singleFields
}
if b.deprecated {
t.Set("deprecated", ast.NewBool(true))
}
setType(t, b)
sortSchema((*ast.StructLit)(t))
return (*ast.StructLit)(t)
}
func (b *builder) add(t *ast.StructLit) {
b.allOf = append(b.allOf, t)
}
func (b *builder) addConjunct(f func(*builder)) {
c := newOASBuilder(b)
f(c)
b.add((*ast.StructLit)(c.finish()))
}
func (b *builder) addRef(v cue.Value, inst *cue.Instance, ref []string) {
name := b.ctx.makeRef(inst, ref)
b.addConjunct(func(b *builder) {
b.allOf = append(b.allOf, ast.NewStruct(
"$ref", ast.NewString(path.Join("#", b.ctx.refPrefix, name))))
})
if b.ctx.inst != inst {
b.ctx.externalRefs[name] = &externalType{
ref: name,
inst: inst,
path: ref,
value: v,
}
}
}
func (b *buildContext) makeRef(inst *cue.Instance, ref []string) string {
ref = append([]string{}, ref...)
for i, s := range ref {
if strings.HasPrefix(s, "#") {
ref[i] = s[1:]
}
}
a := make([]string, 0, len(ref)+3)
if b.nameFunc != nil {
a = append(a, b.nameFunc(inst, ref))
} else {
a = append(a, ref...)
}
return strings.Join(a, ".")
}
func (b *builder) int64(v cue.Value) int64 {
v, _ = v.Default()
i, err := v.Int64()
if err != nil {
b.failf(v, "could not retrieve int: %v", err)
}
return i
}
func (b *builder) intExpr(i int64) ast.Expr {
return &ast.BasicLit{
Kind: token.INT,
Value: fmt.Sprint(i),
}
}
func (b *builder) int(v cue.Value) ast.Expr {
return b.intExpr(b.int64(v))
}
func (b *builder) inta(v cue.Value, offset int64) ast.Expr {
return b.intExpr(b.int64(v) + offset)
}
func (b *builder) decode(v cue.Value) ast.Expr {
v, _ = v.Default()
return v.Syntax().(ast.Expr)
}
func (b *builder) big(v cue.Value) ast.Expr {
v, _ = v.Default()
return v.Syntax().(ast.Expr)
}