1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
// Copyright 2021 CUE Authors
//
// 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 jsonpb
import (
"strconv"
"cuelang.org/go/cue"
"cuelang.org/go/cue/ast"
"cuelang.org/go/cue/errors"
"cuelang.org/go/cue/literal"
"cuelang.org/go/cue/token"
"cuelang.org/go/encoding/protobuf/pbinternal"
)
// TODO: Options:
// - Convert integer strings.
// - URL encoder
// - URL decoder
// An Encoder rewrites CUE values according to the Protobuf to JSON mappings,
// based on a given CUE schema.
//
// It bases the mapping on the underlying CUE type, without consulting Protobuf
// attributes.
//
// Mappings per CUE type:
//
// for any CUE type:
// int: if the expression value is an integer and the schema value is
// an int64, it is converted to a string.
// {}: JSON objects representing any values will be left as is.
// If the CUE type corresponding to the URL can be determined within
// the module context it will be unified.
// _: Adds a `@type` URL (TODO).
type Encoder struct {
schema cue.Value
}
// NewEncoder creates an Encoder for the given schema.
func NewEncoder(schema cue.Value, options ...Option) *Encoder {
return &Encoder{schema: schema}
}
// RewriteFile modifies file, modifying it to conform to the Protocol buffer
// to JSON mapping it in terms of the given schema.
//
// RewriteFile is idempotent, calling it multiples times on an expression gives
// the same result.
func (e *Encoder) RewriteFile(file *ast.File) error {
var enc encoder
enc.rewriteDecls(e.schema, file.Decls)
return enc.errs
}
// RewriteExpr modifies file, modifying it to conform to the Protocol buffer
// to JSON mapping it in terms of the given schema.
//
// RewriteExpr is idempotent, calling it multiples times on an expression gives
// the same result.
func (e *Encoder) RewriteExpr(expr ast.Expr) (ast.Expr, error) {
var enc encoder
x := enc.rewrite(e.schema, expr)
return x, enc.errs
}
type encoder struct {
errs errors.Error
}
func (e *encoder) rewriteDecls(schema cue.Value, decls []ast.Decl) {
for _, f := range decls {
field, ok := f.(*ast.Field)
if !ok {
continue
}
sel := cue.Label(field.Label)
if !sel.IsString() {
continue
}
v := schema.LookupPath(cue.MakePath(sel.Optional()))
if !v.Exists() {
continue
}
field.Value = e.rewrite(v, field.Value)
}
}
func (e *encoder) rewrite(schema cue.Value, expr ast.Expr) (x ast.Expr) {
switch x := expr.(type) {
case *ast.ListLit:
for i, elem := range x.Elts {
v := schema.LookupPath(cue.MakePath(cue.Index(i).Optional()))
if !v.Exists() {
break
}
x.Elts[i] = e.rewrite(v, elem)
}
return expr
case *ast.StructLit:
e.rewriteDecls(schema, x.Elts)
return expr
case *ast.BasicLit:
if x.Kind != token.INT {
break
}
info, err := pbinternal.FromValue("", schema)
if err != nil {
break
}
switch info.Type {
case "int64", "fixed64", "sfixed64", "uint64":
b, ok := expr.(*ast.BasicLit)
if schema.IncompleteKind() == cue.IntKind && ok && b.Kind == token.INT {
b.Kind = token.STRING
b.Value = literal.String.Quote(b.Value)
}
case "int32", "fixed32", "sfixed32", "uint32", "float", "double":
case "varint":
default:
if !info.IsEnum {
break
}
i, err := strconv.ParseInt(x.Value, 10, 32)
if err != nil {
break
}
if s := pbinternal.MatchByInt(schema, i); s != "" {
x.Kind = token.STRING
x.Value = literal.String.Quote(s)
}
}
}
return expr
}
|
