cycle.go

Documentation: cuelang.org/go/encoding/openapi

     1  // Copyright 2021 CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package openapi
    16  
    17  import (
    18  	"cuelang.org/go/cue"
    19  	"cuelang.org/go/cue/errors"
    20  	"cuelang.org/go/cue/token"
    21  	"cuelang.org/go/internal/core/dep"
    22  	"cuelang.org/go/internal/core/eval"
    23  	internalvalue "cuelang.org/go/internal/value"
    24  )
    25  
    26  func (b *builder) pushNode(v cue.Value) {
    27  	_, n := internalvalue.ToInternal(v)
    28  	b.ctx.cycleNodes = append(b.ctx.cycleNodes, n)
    29  }
    30  
    31  func (b *builder) popNode() {
    32  	b.ctx.cycleNodes = b.ctx.cycleNodes[:len(b.ctx.cycleNodes)-1]
    33  }
    34  
    35  func (b *builder) checkCycle(v cue.Value) bool {
    36  	if !b.ctx.expandRefs {
    37  		return true
    38  	}
    39  	r, n := internalvalue.ToInternal(v)
    40  	ctx := eval.NewContext(r, n)
    41  
    42  	err := dep.Visit(nil, ctx, n, func(d dep.Dependency) error {
    43  		for _, m := range b.ctx.cycleNodes {
    44  			if m == d.Node {
    45  				var p token.Pos
    46  				if src := d.Node.Source(); src != nil {
    47  					p = src.Pos()
    48  				}
    49  				err := errors.Newf(p,
    50  					"cycle in reference at %v: cyclic structures not allowed when reference expansion is requested", v.Path())
    51  				b.ctx.errs = errors.Append(b.ctx.errs, err)
    52  				return err
    53  			}
    54  		}
    55  		return nil
    56  	})
    57  
    58  	return err == nil
    59  }
    60
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