symbol.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  	"strconv"
    19  
    20  	"cuelang.org/go/cue"
    21  	"cuelang.org/go/cue/ast"
    22  	"cuelang.org/go/cue/token"
    23  )
    24  
    25  // MatchBySymbol finds an integer value for a given symbol name, representing
    26  // an enum value, and sets it in x.
    27  func MatchBySymbol(v cue.Value, name string, x *ast.BasicLit) bool {
    28  	if op, a := v.Expr(); op == cue.AndOp {
    29  		for _, v := range a {
    30  			if MatchBySymbol(v, name, x) {
    31  				return true
    32  			}
    33  		}
    34  	}
    35  	return matchBySymbol(cue.Dereference(v), name, x)
    36  }
    37  
    38  func matchBySymbol(v cue.Value, name string, x *ast.BasicLit) bool {
    39  	switch op, a := v.Expr(); op {
    40  	case cue.OrOp, cue.AndOp:
    41  		for _, v := range a {
    42  			if matchBySymbol(v, name, x) {
    43  				return true
    44  			}
    45  		}
    46  
    47  	default:
    48  		_, path := v.ReferencePath()
    49  
    50  		a := path.Selectors()
    51  		if len(a) == 0 {
    52  			break
    53  		}
    54  		if s := a[len(a)-1]; !s.IsDefinition() || s.String()[1:] != name {
    55  			break
    56  		}
    57  
    58  		if i, err := v.Int64(); err == nil {
    59  			x.Kind = token.INT
    60  			x.Value = strconv.Itoa(int(i))
    61  			return true
    62  		}
    63  	}
    64  
    65  	return false
    66  }
    67  
    68  // MatchByInt finds a symbol for a given enum value and sets it in x.
    69  func MatchByInt(v cue.Value, val int64) string {
    70  	if op, a := v.Expr(); op == cue.AndOp {
    71  		for _, v := range a {
    72  			if s := MatchByInt(v, val); s != "" {
    73  				return s
    74  			}
    75  		}
    76  	}
    77  	v = cue.Dereference(v)
    78  	return matchByInt(v, val)
    79  }
    80  
    81  func matchByInt(v cue.Value, val int64) string {
    82  	switch op, a := v.Expr(); op {
    83  	case cue.OrOp, cue.AndOp:
    84  		for _, v := range a {
    85  			if s := matchByInt(v, val); s != "" {
    86  				return s
    87  			}
    88  		}
    89  
    90  	default:
    91  		if i, err := v.Int64(); err != nil || i != val {
    92  			break
    93  		}
    94  
    95  		_, path := v.ReferencePath()
    96  		a := path.Selectors()
    97  		if len(a) == 0 {
    98  			break
    99  		}
   100  
   101  		sel := a[len(a)-1]
   102  		if !sel.IsDefinition() {
   103  			break
   104  		}
   105  
   106  		return sel.String()[1:]
   107  	}
   108  
   109  	return ""
   110  }
   111
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