| 1 | // Copyright 2016 The Go Authors. All rights reserved. |
|---|---|
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE file. |
| 4 | |
| 5 | package gcexportdata |
| 6 | |
| 7 | import ( |
| 8 | "fmt" |
| 9 | "go/token" |
| 10 | "go/types" |
| 11 | "os" |
| 12 | ) |
| 13 | |
| 14 | // NewImporter returns a new instance of the types.Importer interface |
| 15 | // that reads type information from export data files written by gc. |
| 16 | // The Importer also satisfies types.ImporterFrom. |
| 17 | // |
| 18 | // Export data files are located using "go build" workspace conventions |
| 19 | // and the build.Default context. |
| 20 | // |
| 21 | // Use this importer instead of go/importer.For("gc", ...) to avoid the |
| 22 | // version-skew problems described in the documentation of this package, |
| 23 | // or to control the FileSet or access the imports map populated during |
| 24 | // package loading. |
| 25 | // |
| 26 | // Deprecated: Use the higher-level API in golang.org/x/tools/go/packages, |
| 27 | // which is more efficient. |
| 28 | func NewImporter(fset *token.FileSet, imports map[string]*types.Package) types.ImporterFrom { |
| 29 | return importer{fset, imports} |
| 30 | } |
| 31 | |
| 32 | type importer struct { |
| 33 | fset *token.FileSet |
| 34 | imports map[string]*types.Package |
| 35 | } |
| 36 | |
| 37 | func (imp importer) Import(importPath string) (*types.Package, error) { |
| 38 | return imp.ImportFrom(importPath, "", 0) |
| 39 | } |
| 40 | |
| 41 | func (imp importer) ImportFrom(importPath, srcDir string, mode types.ImportMode) (_ *types.Package, err error) { |
| 42 | filename, path := Find(importPath, srcDir) |
| 43 | if filename == "" { |
| 44 | if importPath == "unsafe" { |
| 45 | // Even for unsafe, call Find first in case |
| 46 | // the package was vendored. |
| 47 | return types.Unsafe, nil |
| 48 | } |
| 49 | return nil, fmt.Errorf("can't find import: %s", importPath) |
| 50 | } |
| 51 | |
| 52 | if pkg, ok := imp.imports[path]; ok && pkg.Complete() { |
| 53 | return pkg, nil // cache hit |
| 54 | } |
| 55 | |
| 56 | // open file |
| 57 | f, err := os.Open(filename) |
| 58 | if err != nil { |
| 59 | return nil, err |
| 60 | } |
| 61 | defer func() { |
| 62 | f.Close() |
| 63 | if err != nil { |
| 64 | // add file name to error |
| 65 | err = fmt.Errorf("reading export data: %s: %v", filename, err) |
| 66 | } |
| 67 | }() |
| 68 | |
| 69 | r, err := NewReader(f) |
| 70 | if err != nil { |
| 71 | return nil, err |
| 72 | } |
| 73 | |
| 74 | return Read(r, imp.fset, imp.imports, path) |
| 75 | } |
| 76 |
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