attribute.go

Documentation: cuelang.org/go/encoding/protobuf/pbinternal

     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 pbinternal
    16  
    17  import (
    18  	"strings"
    19  	"unicode"
    20  	"unicode/utf8"
    21  
    22  	"cuelang.org/go/cue"
    23  )
    24  
    25  type CompositeType int
    26  
    27  const (
    28  	Normal CompositeType = iota
    29  	List
    30  	Map
    31  )
    32  
    33  type ValueType int
    34  
    35  const (
    36  	Unknown ValueType = iota
    37  	Message
    38  	Int
    39  	Float
    40  	String
    41  	Bytes
    42  	Bool
    43  )
    44  
    45  type Info struct {
    46  	Name    string
    47  	CUEName string
    48  	Attr    cue.Attribute
    49  	Value   cue.Value
    50  
    51  	CompositeType CompositeType
    52  	ValueType     ValueType
    53  	Type          string
    54  
    55  	IsEnum bool
    56  
    57  	// For maps only
    58  	KeyType       ValueType // only for maps
    59  	KeyTypeString string
    60  }
    61  
    62  func FromIter(i *cue.Iterator) (info Info, err error) {
    63  	return FromValue(i.Label(), i.Value())
    64  }
    65  
    66  func FromValue(name string, v cue.Value) (info Info, err error) {
    67  	a := v.Attribute("protobuf")
    68  
    69  	info.Name = name
    70  	info.CUEName = name
    71  
    72  	if a.Err() == nil {
    73  		info.Attr = a
    74  
    75  		s, ok, err := a.Lookup(1, "name")
    76  		if err != nil {
    77  			return info, err
    78  		}
    79  		if ok {
    80  			info.Name = strings.TrimSpace(s)
    81  		}
    82  
    83  		info.Type, err = a.String(1)
    84  		if err != nil {
    85  			return info, err
    86  		}
    87  	}
    88  
    89  	switch v.IncompleteKind() {
    90  	case cue.ListKind:
    91  		info.CompositeType = List
    92  		e, _ := v.Elem()
    93  		if e.Exists() {
    94  			v = e
    95  		} else {
    96  			for i, _ := v.List(); i.Next(); {
    97  				v = i.Value()
    98  				break
    99  			}
   100  		}
   101  
   102  	case cue.StructKind:
   103  		if strings.HasPrefix(info.Type, "map[") {
   104  			a := strings.SplitN(info.Type[len("map["):], "]", 2)
   105  			info.KeyTypeString = strings.TrimSpace(a[0])
   106  			switch info.KeyTypeString {
   107  			case "string":
   108  				info.KeyType = String
   109  			case "bytes":
   110  				info.KeyType = Bytes
   111  			case "double", "float":
   112  				info.KeyType = Float
   113  			case "bool":
   114  				info.KeyType = Bool
   115  			default:
   116  				info.KeyType = Int // Assuming
   117  			}
   118  			info.CompositeType = Map
   119  			v, _ = v.Elem()
   120  		}
   121  	}
   122  
   123  	info.Value = v
   124  
   125  	switch v.IncompleteKind() {
   126  	case cue.StructKind:
   127  		info.ValueType = Message
   128  
   129  	case cue.StringKind:
   130  		info.ValueType = String
   131  
   132  	case cue.BytesKind:
   133  		info.ValueType = Bytes
   134  
   135  	case cue.BoolKind:
   136  		info.ValueType = Bool
   137  
   138  	case cue.IntKind:
   139  		info.ValueType = Int
   140  		r, _ := utf8.DecodeRuneInString(info.Type)
   141  		info.IsEnum = unicode.In(r, unicode.Upper)
   142  
   143  	case cue.FloatKind, cue.NumberKind:
   144  		info.ValueType = Float
   145  	}
   146  
   147  	return info, nil
   148  }
   149
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