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-rw-r--r--src/go/importer/importer.go122
-rw-r--r--src/go/importer/importer_test.go87
2 files changed, 209 insertions, 0 deletions
diff --git a/src/go/importer/importer.go b/src/go/importer/importer.go
new file mode 100644
index 0000000..23118d3
--- /dev/null
+++ b/src/go/importer/importer.go
@@ -0,0 +1,122 @@
+// Copyright 2015 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 importer provides access to export data importers.
+package importer
+
+import (
+ "go/build"
+ "go/internal/gccgoimporter"
+ "go/internal/gcimporter"
+ "go/internal/srcimporter"
+ "go/token"
+ "go/types"
+ "io"
+ "runtime"
+)
+
+// A Lookup function returns a reader to access package data for
+// a given import path, or an error if no matching package is found.
+type Lookup func(path string) (io.ReadCloser, error)
+
+// ForCompiler returns an Importer for importing from installed packages
+// for the compilers "gc" and "gccgo", or for importing directly
+// from the source if the compiler argument is "source". In this
+// latter case, importing may fail under circumstances where the
+// exported API is not entirely defined in pure Go source code
+// (if the package API depends on cgo-defined entities, the type
+// checker won't have access to those).
+//
+// The lookup function is called each time the resulting importer needs
+// to resolve an import path. In this mode the importer can only be
+// invoked with canonical import paths (not relative or absolute ones);
+// it is assumed that the translation to canonical import paths is being
+// done by the client of the importer.
+//
+// A lookup function must be provided for correct module-aware operation.
+// Deprecated: If lookup is nil, for backwards-compatibility, the importer
+// will attempt to resolve imports in the $GOPATH workspace.
+func ForCompiler(fset *token.FileSet, compiler string, lookup Lookup) types.Importer {
+ switch compiler {
+ case "gc":
+ return &gcimports{
+ fset: fset,
+ packages: make(map[string]*types.Package),
+ lookup: lookup,
+ }
+
+ case "gccgo":
+ var inst gccgoimporter.GccgoInstallation
+ if err := inst.InitFromDriver("gccgo"); err != nil {
+ return nil
+ }
+ return &gccgoimports{
+ packages: make(map[string]*types.Package),
+ importer: inst.GetImporter(nil, nil),
+ lookup: lookup,
+ }
+
+ case "source":
+ if lookup != nil {
+ panic("source importer for custom import path lookup not supported (issue #13847).")
+ }
+
+ return srcimporter.New(&build.Default, fset, make(map[string]*types.Package))
+ }
+
+ // compiler not supported
+ return nil
+}
+
+// For calls ForCompiler with a new FileSet.
+//
+// Deprecated: Use ForCompiler, which populates a FileSet
+// with the positions of objects created by the importer.
+func For(compiler string, lookup Lookup) types.Importer {
+ return ForCompiler(token.NewFileSet(), compiler, lookup)
+}
+
+// Default returns an Importer for the compiler that built the running binary.
+// If available, the result implements types.ImporterFrom.
+func Default() types.Importer {
+ return For(runtime.Compiler, nil)
+}
+
+// gc importer
+
+type gcimports struct {
+ fset *token.FileSet
+ packages map[string]*types.Package
+ lookup Lookup
+}
+
+func (m *gcimports) Import(path string) (*types.Package, error) {
+ return m.ImportFrom(path, "" /* no vendoring */, 0)
+}
+
+func (m *gcimports) ImportFrom(path, srcDir string, mode types.ImportMode) (*types.Package, error) {
+ if mode != 0 {
+ panic("mode must be 0")
+ }
+ return gcimporter.Import(m.fset, m.packages, path, srcDir, m.lookup)
+}
+
+// gccgo importer
+
+type gccgoimports struct {
+ packages map[string]*types.Package
+ importer gccgoimporter.Importer
+ lookup Lookup
+}
+
+func (m *gccgoimports) Import(path string) (*types.Package, error) {
+ return m.ImportFrom(path, "" /* no vendoring */, 0)
+}
+
+func (m *gccgoimports) ImportFrom(path, srcDir string, mode types.ImportMode) (*types.Package, error) {
+ if mode != 0 {
+ panic("mode must be 0")
+ }
+ return m.importer(m.packages, path, srcDir, m.lookup)
+}
diff --git a/src/go/importer/importer_test.go b/src/go/importer/importer_test.go
new file mode 100644
index 0000000..0f5121d
--- /dev/null
+++ b/src/go/importer/importer_test.go
@@ -0,0 +1,87 @@
+// 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 importer
+
+import (
+ "go/token"
+ "internal/testenv"
+ "io"
+ "os"
+ "os/exec"
+ "runtime"
+ "strings"
+ "testing"
+)
+
+func TestForCompiler(t *testing.T) {
+ testenv.MustHaveGoBuild(t)
+
+ const thePackage = "math/big"
+ out, err := exec.Command(testenv.GoToolPath(t), "list", "-f={{context.Compiler}}:{{.Target}}", thePackage).CombinedOutput()
+ if err != nil {
+ t.Fatalf("go list %s: %v\n%s", thePackage, err, out)
+ }
+ target := strings.TrimSpace(string(out))
+ i := strings.Index(target, ":")
+ compiler, target := target[:i], target[i+1:]
+ if !strings.HasSuffix(target, ".a") {
+ t.Fatalf("unexpected package %s target %q (not *.a)", thePackage, target)
+ }
+
+ if compiler == "gccgo" {
+ t.Skip("golang.org/issue/22500")
+ }
+
+ fset := token.NewFileSet()
+
+ t.Run("LookupDefault", func(t *testing.T) {
+ imp := ForCompiler(fset, compiler, nil)
+ pkg, err := imp.Import(thePackage)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if pkg.Path() != thePackage {
+ t.Fatalf("Path() = %q, want %q", pkg.Path(), thePackage)
+ }
+
+ // Check that the fileset positions are accurate.
+ // https://github.com/golang/go#28995
+ mathBigInt := pkg.Scope().Lookup("Int")
+ posn := fset.Position(mathBigInt.Pos()) // "$GOROOT/src/math/big/int.go:25:1"
+ filename := strings.Replace(posn.Filename, "$GOROOT", runtime.GOROOT(), 1)
+ data, err := os.ReadFile(filename)
+ if err != nil {
+ t.Fatalf("can't read file containing declaration of math/big.Int: %v", err)
+ }
+ lines := strings.Split(string(data), "\n")
+ if posn.Line > len(lines) || !strings.HasPrefix(lines[posn.Line-1], "type Int") {
+ t.Fatalf("Object %v position %s does not contain its declaration",
+ mathBigInt, posn)
+ }
+ })
+
+ t.Run("LookupCustom", func(t *testing.T) {
+ lookup := func(path string) (io.ReadCloser, error) {
+ if path != "math/bigger" {
+ t.Fatalf("lookup called with unexpected path %q", path)
+ }
+ f, err := os.Open(target)
+ if err != nil {
+ t.Fatal(err)
+ }
+ return f, nil
+ }
+ imp := ForCompiler(fset, compiler, lookup)
+ pkg, err := imp.Import("math/bigger")
+ if err != nil {
+ t.Fatal(err)
+ }
+ // Even though we open math/big.a, the import request was for math/bigger
+ // and that should be recorded in pkg.Path(), at least for the gc toolchain.
+ if pkg.Path() != "math/bigger" {
+ t.Fatalf("Path() = %q, want %q", pkg.Path(), "math/bigger")
+ }
+ })
+}