-
Notifications
You must be signed in to change notification settings - Fork 0
/
srcimporter.go
207 lines (183 loc) · 6.6 KB
/
srcimporter.go
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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package srcimporter implements importing directly
// from source files rather than installed packages.
package srcimporter // import "go/internal/srcimporter"
import (
"fmt"
"go/ast"
"go/build"
"go/parser"
"go/token"
"go/types"
"path/filepath"
"sync"
)
// An Importer provides the context for importing packages from source code.
type Importer struct {
ctxt *build.Context
fset *token.FileSet
sizes types.Sizes
packages map[string]*types.Package
}
// NewImporter returns a new Importer for the given context, file set, and map
// of packages. The context is used to resolve import paths to package paths,
// and identifying the files belonging to the package. If the context provides
// non-nil file system functions, they are used instead of the regular package
// os functions. The file set is used to track position information of package
// files; and imported packages are added to the packages map.
func New(ctxt *build.Context, fset *token.FileSet, packages map[string]*types.Package) *Importer {
return &Importer{
ctxt: ctxt,
fset: fset,
sizes: types.SizesFor(ctxt.Compiler, ctxt.GOARCH), // uses go/types default if GOARCH not found
packages: packages,
}
}
// Importing is a sentinel taking the place in Importer.packages
// for a package that is in the process of being imported.
var importing types.Package
// Import(path) is a shortcut for ImportFrom(path, ".", 0).
func (p *Importer) Import(path string) (*types.Package, error) {
return p.ImportFrom(path, ".", 0) // use "." rather than "" (see issue #24441)
}
// ImportFrom imports the package with the given import path resolved from the given srcDir,
// adds the new package to the set of packages maintained by the importer, and returns the
// package. Package path resolution and file system operations are controlled by the context
// maintained with the importer. The import mode must be zero but is otherwise ignored.
// Packages that are not comprised entirely of pure Go files may fail to import because the
// type checker may not be able to determine all exported entities (e.g. due to cgo dependencies).
func (p *Importer) ImportFrom(path, srcDir string, mode types.ImportMode) (*types.Package, error) {
if mode != 0 {
panic("non-zero import mode")
}
if abs, err := p.absPath(srcDir); err == nil { // see issue #14282
srcDir = abs
}
bp, err := p.ctxt.Import(path, srcDir, 0)
if err != nil {
return nil, err // err may be *build.NoGoError - return as is
}
// package unsafe is known to the type checker
if bp.ImportPath == "unsafe" {
return types.Unsafe, nil
}
// no need to re-import if the package was imported completely before
pkg := p.packages[bp.ImportPath]
if pkg != nil {
if pkg == &importing {
return nil, fmt.Errorf("import cycle through package %q", bp.ImportPath)
}
if !pkg.Complete() {
// Package exists but is not complete - we cannot handle this
// at the moment since the source importer replaces the package
// wholesale rather than augmenting it (see #19337 for details).
// Return incomplete package with error (see #16088).
return pkg, fmt.Errorf("reimported partially imported package %q", bp.ImportPath)
}
return pkg, nil
}
p.packages[bp.ImportPath] = &importing
defer func() {
// clean up in case of error
// TODO(gri) Eventually we may want to leave a (possibly empty)
// package in the map in all cases (and use that package to
// identify cycles). See also issue 16088.
if p.packages[bp.ImportPath] == &importing {
p.packages[bp.ImportPath] = nil
}
}()
var filenames []string
filenames = append(filenames, bp.GoFiles...)
filenames = append(filenames, bp.CgoFiles...)
files, err := p.parseFiles(bp.Dir, filenames)
if err != nil {
return nil, err
}
// type-check package files
var firstHardErr error
conf := types.Config{
IgnoreFuncBodies: true,
FakeImportC: true,
// continue type-checking after the first error
Error: func(err error) {
if firstHardErr == nil && !err.(types.Error).Soft {
firstHardErr = err
}
},
Importer: p,
Sizes: p.sizes,
}
pkg, err = conf.Check(bp.ImportPath, p.fset, files, nil)
if err != nil {
// If there was a hard error it is possibly unsafe
// to use the package as it may not be fully populated.
// Do not return it (see also #20837, #20855).
if firstHardErr != nil {
pkg = nil
err = firstHardErr // give preference to first hard error over any soft error
}
return pkg, fmt.Errorf("type-checking package %q failed (%v)", bp.ImportPath, err)
}
if firstHardErr != nil {
// this can only happen if we have a bug in go/types
panic("package is not safe yet no error was returned")
}
p.packages[bp.ImportPath] = pkg
return pkg, nil
}
func (p *Importer) parseFiles(dir string, filenames []string) ([]*ast.File, error) {
open := p.ctxt.OpenFile // possibly nil
files := make([]*ast.File, len(filenames))
errors := make([]error, len(filenames))
var wg sync.WaitGroup
wg.Add(len(filenames))
for i, filename := range filenames {
go func(i int, filepath string) {
defer wg.Done()
if open != nil {
src, err := open(filepath)
if err != nil {
errors[i] = fmt.Errorf("opening package file %s failed (%v)", filepath, err)
return
}
files[i], errors[i] = parser.ParseFile(p.fset, filepath, src, 0)
src.Close() // ignore Close error - parsing may have succeeded which is all we need
} else {
// Special-case when ctxt doesn't provide a custom OpenFile and use the
// parser's file reading mechanism directly. This appears to be quite a
// bit faster than opening the file and providing an io.ReaderCloser in
// both cases.
// TODO(gri) investigate performance difference (issue #19281)
files[i], errors[i] = parser.ParseFile(p.fset, filepath, nil, 0)
}
}(i, p.joinPath(dir, filename))
}
wg.Wait()
// if there are errors, return the first one for deterministic results
for _, err := range errors {
if err != nil {
return nil, err
}
}
return files, nil
}
// context-controlled file system operations
func (p *Importer) absPath(path string) (string, error) {
// TODO(gri) This should be using p.ctxt.AbsPath which doesn't
// exist but probably should. See also issue #14282.
return filepath.Abs(path)
}
func (p *Importer) isAbsPath(path string) bool {
if f := p.ctxt.IsAbsPath; f != nil {
return f(path)
}
return filepath.IsAbs(path)
}
func (p *Importer) joinPath(elem ...string) string {
if f := p.ctxt.JoinPath; f != nil {
return f(elem...)
}
return filepath.Join(elem...)
}