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
|
// Copyright 2018 Google LLC
//
// 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 main
import (
"bytes"
"fmt"
"go/ast"
"go/format"
"go/parser"
"go/token"
"strconv"
"gvisor.googlesource.com/gvisor/tools/go_generics/globals"
)
type importedPackage struct {
newName string
path string
}
// updateImportIdent modifies the given import identifier with the new name
// stored in the used map. If the identifier doesn't exist in the used map yet,
// a new name is generated and inserted into the map.
func updateImportIdent(orig string, imports mapValue, id *ast.Ident, used map[string]*importedPackage) error {
importName := id.Name
// If the name is already in the table, just use the new name.
m := used[importName]
if m != nil {
id.Name = m.newName
return nil
}
// Create a new entry in the used map.
path := imports[importName]
if path == "" {
return fmt.Errorf("Unknown path to package '%s', used in '%s'", importName, orig)
}
m = &importedPackage{
newName: fmt.Sprintf("__generics_imported%d", len(used)),
path: strconv.Quote(path),
}
used[importName] = m
id.Name = m.newName
return nil
}
// convertExpression creates a new string that is a copy of the input one with
// all imports references renamed to the names in the "used" map. If the
// referenced import isn't in "used" yet, a new one is created based on the path
// in "imports" and stored in "used". For example, if string s is
// "math.MaxUint32-math.MaxUint16+10", it would be converted to
// "x.MaxUint32-x.MathUint16+10", where x is a generated name.
func convertExpression(s string, imports mapValue, used map[string]*importedPackage) (string, error) {
// Parse the expression in the input string.
expr, err := parser.ParseExpr(s)
if err != nil {
return "", fmt.Errorf("Unable to parse \"%s\": %v", s, err)
}
// Go through the AST and update references.
var retErr error
ast.Inspect(expr, func(n ast.Node) bool {
switch x := n.(type) {
case *ast.SelectorExpr:
if id := globals.GetIdent(x.X); id != nil {
if err := updateImportIdent(s, imports, id, used); err != nil {
retErr = err
}
return false
}
}
return true
})
if retErr != nil {
return "", retErr
}
// Convert the modified AST back to a string.
fset := token.NewFileSet()
var buf bytes.Buffer
if err := format.Node(&buf, fset, expr); err != nil {
return "", err
}
return string(buf.Bytes()), nil
}
// updateImports replaces all maps in the input slice with copies where the
// mapped values have had all references to imported packages renamed to
// generated names. It also returns an import declaration for all the renamed
// import packages.
//
// For example, if the input maps contains A=math.B and C=math.D, the updated
// maps will instead contain A=__generics_imported0.B and
// C=__generics_imported0.C, and the 'import __generics_imported0 "math"' would
// be returned as the import declaration.
func updateImports(maps []mapValue, imports mapValue) (ast.Decl, error) {
importsUsed := make(map[string]*importedPackage)
// Update all maps.
for i, m := range maps {
newMap := make(mapValue)
for n, e := range m {
updated, err := convertExpression(e, imports, importsUsed)
if err != nil {
return nil, err
}
newMap[n] = updated
}
maps[i] = newMap
}
// Nothing else to do if no imports are used in the expressions.
if len(importsUsed) == 0 {
return nil, nil
}
// Create spec array for each new import.
specs := make([]ast.Spec, 0, len(importsUsed))
for _, i := range importsUsed {
specs = append(specs, &ast.ImportSpec{
Name: &ast.Ident{Name: i.newName},
Path: &ast.BasicLit{Value: i.path},
})
}
return &ast.GenDecl{
Tok: token.IMPORT,
Specs: specs,
Lparen: token.NoPos + 1,
}, nil
}
|
