pulumi/pkg/codegen/hcl2/model/traversable.go

112 lines
3.2 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 (
"strings"
"github.com/hashicorp/hcl/v2"
"github.com/pulumi/pulumi/sdk/v3/go/common/util/contract"
"github.com/zclconf/go-cty/cty"
)
// Traversable represents an entity that can be traversed by an HCL2 traverser.
type Traversable interface {
// Traverse attempts to traverse the receiver using the given traverser.
Traverse(t hcl.Traverser) (Traversable, hcl.Diagnostics)
}
// TypedTraversable is a Traversable that has an associated type.
type TypedTraversable interface {
Traversable
Type() Type
}
// ValueTraversable is a Traversable that has an associated value.
type ValueTraversable interface {
Traversable
Value(context *hcl.EvalContext) (cty.Value, hcl.Diagnostics)
}
// GetTraversableType returns the type of the given Traversable:
// - If the Traversable is a TypedTraversable, this returns t.Type()
// - If the Traversable is a Type, this returns t
// - Otherwise, this returns DynamicType
func GetTraversableType(t Traversable) Type {
switch t := t.(type) {
case TypedTraversable:
return t.Type()
case Type:
return t
default:
return DynamicType
}
}
// GetTraverserKey extracts the value and type of the key associated with the given traverser.
func GetTraverserKey(t hcl.Traverser) (cty.Value, Type) {
switch t := t.(type) {
case hcl.TraverseAttr:
return cty.StringVal(t.Name), StringType
case hcl.TraverseIndex:
if t.Key.Type().Equals(typeCapsule) {
return cty.DynamicVal, *(t.Key.EncapsulatedValue().(*Type))
}
return t.Key, ctyTypeToType(t.Key.Type(), false)
default:
contract.Failf("unexpected traverser of type %T (%v)", t, t.SourceRange())
return cty.DynamicVal, DynamicType
}
}
// bindTraversalParts computes the type for each element of the given traversal.
func bindTraversalParts(receiver Traversable, traversal hcl.Traversal,
allowMissingVariables bool,
) ([]Traversable, hcl.Diagnostics) {
parts := make([]Traversable, len(traversal)+1)
parts[0] = receiver
var diagnostics hcl.Diagnostics
for i, part := range traversal {
nextReceiver, partDiags := parts[i].Traverse(part)
// TODO(pdg): proper options for Traverse
if allowMissingVariables {
var diags hcl.Diagnostics
for _, d := range partDiags {
if !strings.HasPrefix(d.Summary, "undefined variable") {
diags = append(diags, d)
}
}
partDiags = diags
}
parts[i+1], diagnostics = nextReceiver, append(diagnostics, partDiags...)
}
switch parts[len(parts)-1].(type) {
case TypedTraversable, Type:
// OK
default:
// TODO(pdg): improve this diagnostic
diagnostics = append(diagnostics, undefinedVariable("",
traversal.SourceRange(), allowMissingVariables))
}
return parts, diagnostics
}