115 lines
4.2 KiB
Go
115 lines
4.2 KiB
Go
// Copyright 2016-2020, Pulumi Corporation.
|
|
//
|
|
// 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 model
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"github.com/hashicorp/hcl/v2"
|
|
"github.com/hashicorp/hcl/v2/hclsyntax"
|
|
"github.com/pulumi/pulumi/pkg/v3/codegen/hcl2/syntax"
|
|
)
|
|
|
|
// PromiseType represents eventual values that do not carry additional information.
|
|
type PromiseType struct {
|
|
// ElementType is the element type of the promise.
|
|
ElementType Type
|
|
}
|
|
|
|
// NewPromiseType creates a new promise type with the given element type after replacing any promise types within
|
|
// the element type with their respective element types.
|
|
func NewPromiseType(elementType Type) *PromiseType {
|
|
return &PromiseType{ElementType: ResolvePromises(elementType)}
|
|
}
|
|
|
|
// SyntaxNode returns the syntax node for the type. This is always syntax.None.
|
|
func (*PromiseType) SyntaxNode() hclsyntax.Node {
|
|
return syntax.None
|
|
}
|
|
|
|
// Traverse attempts to traverse the promise type with the given traverser. The result type of traverse(promise(T))
|
|
// is promise(traverse(T)).
|
|
func (t *PromiseType) Traverse(traverser hcl.Traverser) (Traversable, hcl.Diagnostics) {
|
|
element, diagnostics := t.ElementType.Traverse(traverser)
|
|
return NewPromiseType(element.(Type)), diagnostics
|
|
}
|
|
|
|
// Equals returns true if this type has the same identity as the given type.
|
|
func (t *PromiseType) Equals(other Type) bool {
|
|
return t.equals(other, nil)
|
|
}
|
|
|
|
func (t *PromiseType) equals(other Type, seen map[Type]struct{}) bool {
|
|
if t == other {
|
|
return true
|
|
}
|
|
otherPromise, ok := other.(*PromiseType)
|
|
return ok && t.ElementType.equals(otherPromise.ElementType, seen)
|
|
}
|
|
|
|
// AssignableFrom returns true if this type is assignable from the indicated source type. A promise(T) is assignable
|
|
// from values of type promise(U) and U, where T is assignable from U.
|
|
func (t *PromiseType) AssignableFrom(src Type) bool {
|
|
return assignableFrom(t, src, func() bool {
|
|
if src, ok := src.(*PromiseType); ok {
|
|
return t.ElementType.AssignableFrom(src.ElementType)
|
|
}
|
|
return t.ElementType.AssignableFrom(src)
|
|
})
|
|
}
|
|
|
|
// ConversionFrom returns the kind of conversion (if any) that is possible from the source type to this type. An
|
|
// promise(T) is convertible from a type U or promise(U) if U is convertible to T. If the conversion from U to T is
|
|
// unsafe, the entire conversion is unsafe. Otherwise, the conversion is safe.
|
|
func (t *PromiseType) ConversionFrom(src Type) ConversionKind {
|
|
return t.conversionFrom(src, false, nil)
|
|
}
|
|
|
|
func (t *PromiseType) conversionFrom(src Type, unifying bool, seen map[Type]struct{}) ConversionKind {
|
|
return conversionFrom(t, src, unifying, seen, func() ConversionKind {
|
|
if src, ok := src.(*PromiseType); ok {
|
|
return t.ElementType.conversionFrom(src.ElementType, unifying, seen)
|
|
}
|
|
return t.ElementType.conversionFrom(src, unifying, seen)
|
|
})
|
|
}
|
|
|
|
func (t *PromiseType) String() string {
|
|
return t.string(nil)
|
|
}
|
|
|
|
func (t *PromiseType) string(seen map[Type]struct{}) string {
|
|
return fmt.Sprintf("promise(%s)", t.ElementType.string(seen))
|
|
}
|
|
|
|
func (t *PromiseType) unify(other Type) (Type, ConversionKind) {
|
|
return unify(t, other, func() (Type, ConversionKind) {
|
|
switch other := other.(type) {
|
|
case *PromiseType:
|
|
// If the other type is a promise type, unify based on the element type.
|
|
elementType, conversionKind := t.ElementType.unify(other.ElementType)
|
|
return NewPromiseType(elementType), conversionKind
|
|
case *OutputType:
|
|
// If the other type is an output type, prefer the optional type, but unify the element type.
|
|
elementType, conversionKind := t.unify(other.ElementType)
|
|
return NewOutputType(elementType), conversionKind
|
|
default:
|
|
// Prefer the promise type.
|
|
return t, t.conversionFrom(other, true, nil)
|
|
}
|
|
})
|
|
}
|
|
|
|
func (t *PromiseType) isType() {}
|