// 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 ( ) // 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 ( *token.FileSet, string, Lookup) types.Importer { switch { case "gc": return &gcimports{ fset: , packages: make(map[string]*types.Package), lookup: , } case "gccgo": var gccgoimporter.GccgoInstallation if := .InitFromDriver("gccgo"); != nil { return nil } return &gccgoimports{ packages: make(map[string]*types.Package), importer: .GetImporter(nil, nil), lookup: , } case "source": if != nil { panic("source importer for custom import path lookup not supported (issue #13847).") } return srcimporter.New(&build.Default, , 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 ( string, Lookup) types.Importer { return ForCompiler(token.NewFileSet(), , ) } // Default returns an Importer for the compiler that built the running binary. // If available, the result implements types.ImporterFrom. func () types.Importer { return For(runtime.Compiler, nil) } // gc importer type gcimports struct { fset *token.FileSet packages map[string]*types.Package lookup Lookup } func ( *gcimports) ( string) (*types.Package, error) { return .ImportFrom(, "" /* no vendoring */, 0) } func ( *gcimports) (, string, types.ImportMode) (*types.Package, error) { if != 0 { panic("mode must be 0") } return gcimporter.Import(.fset, .packages, , , .lookup) } // gccgo importer type gccgoimports struct { packages map[string]*types.Package importer gccgoimporter.Importer lookup Lookup } func ( *gccgoimports) ( string) (*types.Package, error) { return .ImportFrom(, "" /* no vendoring */, 0) } func ( *gccgoimports) (, string, types.ImportMode) (*types.Package, error) { if != 0 { panic("mode must be 0") } return .importer(.packages, , , .lookup) }