cuelang.org/go@v0.13.0/pkg/encoding/yaml/manual.go (about)

     1  // Copyright 2018 The 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 yaml
    16  
    17  import (
    18  	"bytes"
    19  	"io"
    20  
    21  	"cuelang.org/go/cue"
    22  	"cuelang.org/go/cue/ast"
    23  	"cuelang.org/go/internal/core/adt"
    24  	cueyaml "cuelang.org/go/internal/encoding/yaml"
    25  	"cuelang.org/go/internal/pkg"
    26  	"cuelang.org/go/internal/value"
    27  )
    28  
    29  // Marshal returns the YAML encoding of v.
    30  func Marshal(v cue.Value) (string, error) {
    31  	if err := v.Validate(cue.Concrete(true)); err != nil {
    32  		return "", err
    33  	}
    34  	n := v.Syntax(cue.Final(), cue.Concrete(true))
    35  	b, err := cueyaml.Encode(n)
    36  	return string(b), err
    37  }
    38  
    39  // MarshalStream returns the YAML encoding of v.
    40  func MarshalStream(v cue.Value) (string, error) {
    41  	// TODO: return an io.Reader and allow asynchronous processing.
    42  	iter, err := v.List()
    43  	if err != nil {
    44  		return "", err
    45  	}
    46  	buf := &bytes.Buffer{}
    47  	for i := 0; iter.Next(); i++ {
    48  		if i > 0 {
    49  			buf.WriteString("---\n")
    50  		}
    51  		v := iter.Value()
    52  		if err := v.Validate(cue.Concrete(true)); err != nil {
    53  			return "", err
    54  		}
    55  		n := v.Syntax(cue.Final(), cue.Concrete(true))
    56  		b, err := cueyaml.Encode(n)
    57  		if err != nil {
    58  			return "", err
    59  		}
    60  		buf.Write(b)
    61  	}
    62  	return buf.String(), nil
    63  }
    64  
    65  // Unmarshal parses the YAML to a CUE expression.
    66  func Unmarshal(data []byte) (ast.Expr, error) {
    67  	return cueyaml.Unmarshal("", data)
    68  }
    69  
    70  // UnmarshalStream parses the YAML to a CUE list expression on success.
    71  func UnmarshalStream(data []byte) (ast.Expr, error) {
    72  	d := cueyaml.NewDecoder("", data)
    73  	a := []ast.Expr{}
    74  	for {
    75  		x, err := d.Decode()
    76  		if err == io.EOF {
    77  			break
    78  		}
    79  		if err != nil {
    80  			return nil, err
    81  		}
    82  		a = append(a, x)
    83  	}
    84  
    85  	return ast.NewList(a...), nil
    86  }
    87  
    88  // Validate validates YAML and confirms it is an instance of schema.
    89  // If the YAML source is a stream, every object must match v.
    90  func Validate(b []byte, v pkg.Schema) (bool, error) {
    91  	// This function is left for Go documentation. The package entry calls
    92  	// cueyaml.Validate directly, passing it the call context.
    93  
    94  	ctx := value.OpContext(v)
    95  	return cueyaml.Validate(ctx, b, v)
    96  }
    97  
    98  // validate is the actual implementation of Validate.
    99  func validate(c *adt.OpContext, b []byte, v pkg.Schema) (bool, error) {
   100  	return cueyaml.Validate(c, b, v)
   101  }
   102  
   103  // ValidatePartial validates YAML and confirms it matches the constraints
   104  // specified by v using unification. This means that b must be consistent with,
   105  // but does not have to be an instance of v. If the YAML source is a stream,
   106  // every object must match v.
   107  func ValidatePartial(b []byte, v pkg.Schema) (bool, error) {
   108  	// This function is left for Go documentation. The package entry calls
   109  	// cueyaml.ValidatePartial directly, passing it the call context.
   110  
   111  	ctx := value.OpContext(v)
   112  	return cueyaml.ValidatePartial(ctx, b, v)
   113  }
   114  
   115  // validatePartial is the actual implementation of ValidatePartial.
   116  func validatePartial(c *adt.OpContext, b []byte, v pkg.Schema) (bool, error) {
   117  	return cueyaml.ValidatePartial(c, b, v)
   118  }