// 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.
//
// These functions, which are mostly deprecated, date from before the
// introduction of modules in release Go 1.11. They should no longer
// be relied on except for use in test cases using small programs that
// depend only on the standard library. For reliable module-aware
// loading of type information, use the packages.Load function from
// golang.org/x/tools/go/packages.
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].
//
// Default may be convenient for use in the simplest of cases, but
// most clients should instead use [ForCompiler], which accepts a
// [token.FileSet] from the caller; without it, all position
// information derived from the Importer will be incorrect and
// misleading. See also the package documentation.
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)
}