encoding/jsonschema: add several validators

- minLength
- maxLength
- additionalItems

Change-Id: I09d9e353914b0fece70a26d97db5c4665c4e5f8b
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/5651
Reviewed-by: roger peppe <rogpeppe@gmail.com>

encoding/jsonschema/constraints.go

@@ -307,6 +307,21 @@ var constraints = []*constraint{
 		s.addConjunct(&ast.UnaryExpr{Op: token.MAT, X: s.string(n)})
 	}),
 
+	p0("minLength", func(n cue.Value, s *state) {
+		s.usedTypes |= cue.StringKind
+		min := s.number(n)
+		strings := s.addImport("strings")
+		s.addConjunct(ast.NewCall(ast.NewSel(strings, "MinRunes"), min))
+
+	}),
+
+	p0("maxLength", func(n cue.Value, s *state) {
+		s.usedTypes |= cue.StringKind
+		max := s.number(n)
+		strings := s.addImport("strings")
+		s.addConjunct(ast.NewCall(ast.NewSel(strings, "MaxRunes"), max))
+	}),
+
 	p0d("contentMediaType", 7, func(n cue.Value, s *state) {
 		s.usedTypes |= cue.StringKind
 	}),
@@ -530,9 +545,6 @@ var constraints = []*constraint{
 
 	p0("items", func(n cue.Value, s *state) {
 		s.usedTypes |= cue.ListKind
-		if s.list != nil {
-			s.errf(n, `"items" declared more than once, previous declaration at %s`, s.list.Pos())
-		}
 		switch n.Kind() {
 		case cue.StructKind:
 			elem := s.schema(n)
@@ -546,13 +558,22 @@ var constraints = []*constraint{
 				ast.SetRelPos(v, token.NoRelPos)
 				a = append(a, v)
 			}
-			s.addConjunct(ast.NewList(a...))
+			s.list = ast.NewList(a...)
+			s.addConjunct(s.list)
 
 		default:
 			s.errf(n, `value of "items" must be an object or array`)
 		}
 	}),
 
+	p0("additionalItems", func(n cue.Value, s *state) {
+		s.usedTypes |= cue.ListKind
+		if s.list != nil {
+			elem := s.schema(n)
+			s.list.Elts = append(s.list.Elts, &ast.Ellipsis{Type: elem})
+		}
+	}),
+
 	p0("contains", func(n cue.Value, s *state) {
 		s.usedTypes |= cue.ListKind
 		list := s.addImport("list")
@@ -562,6 +583,8 @@ var constraints = []*constraint{
 		}
 	}),
 
+	// TODO: min/maxContains
+
 	p0("minItems", func(n cue.Value, s *state) {
 		s.usedTypes |= cue.ListKind
 		list := s.addImport("list")

encoding/jsonschema/decode.go

@@ -237,8 +237,7 @@ func (s *state) hasConstraints() bool {
 		len(s.patterns) > 0 ||
 		s.title != "" ||
 		s.description != "" ||
-		s.obj != nil ||
-		s.list != nil
+		s.obj != nil
 }
 
 const allTypes = cue.NullKind | cue.BoolKind | cue.NumberKind | cue.IntKind |

encoding/jsonschema/testdata/basic.txtar

@@ -15,7 +15,9 @@
         "name": { "type": "string" },
         "address": {
             "description": "where does this person live?",
-            "type": "string"
+            "type": "string",
+			"minLength": 4,
+			"maxLength": 20
         },
         "children": {
           "description": "A very large comment that will be wrapped after a certain line length. Let's keep on going and see what happens.",
@@ -33,6 +35,8 @@
 }
 
 -- out.cue --
+import "strings"
+
 // Main schema
 //
 // Specify who you are and all.
@@ -43,7 +47,7 @@ Schema :: {
 		name: string
 
 		// where does this person live?
-		address?: string
+		address?: strings.MinRunes(4) & strings.MaxRunes(20)
 
 		// A very large comment that will be wrapped after a certain line
 		// length. Let's keep on going and see what happens.

encoding/jsonschema/testdata/list.txtar

@@ -25,6 +25,14 @@ properties:
     maxItems: 9
     uniqueItems: true
 
+  additional:
+    type: array
+    items:
+      - type: integer
+      - type: integer
+    additionalItems:
+      type: string
+
 additionalProperties: false
 
 -- out.cue --
@@ -35,4 +43,5 @@ Schema :: {
 	tuple?: [string, int, 2]
 	has?:  list.Contains(3)
 	size?: list.MinItems(3) & list.MaxItems(9) & list.UniqueItems()
+	additional?: [int, int, ...string]
 }