gcimporter

Documentation

Overview

Package gcimporter15 provides various functions for reading gc-generated object files that can be used to implement the Importer interface defined by the Go 1.5 standard library package.

This package serves as a stop-gap for missing features in the standard library's go/importer package, specifically customizable package data lookup. This package should be deleted once that functionality becomes available in the standard library.

Index

• func BExportData(pkg *types.Package) []byte
• func BImportData(imports map[string]*types.Package, data []byte, path string) (int, *types.Package, error)
• func FindExportData(r *bufio.Reader) (hdr string, err error)
• func FindPkg(path, srcDir string) (filename, id string)
• func Import(packages map[string]*types.Package, path, srcDir string) (pkg *types.Package, err error)
• func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error)

Functions

func BExportData

func BExportData(pkg *types.Package) []byte

BExportData returns binary export data for pkg.

It is not safe to call this function on a package containing errors. TODO(adonovan): add InvalidType to the protocol and lift this restriction.

func BImportData

func BImportData(imports map[string]*types.Package, data []byte, path string) (int, *types.Package, error)

BImportData imports a package from the serialized package data and returns the number of bytes consumed and a reference to the package. If data is obviously malformed, an error is returned but in general it is not recommended to call BImportData on untrusted data.

func FindExportData

func FindExportData(r *bufio.Reader) (hdr string, err error)

FindExportData positions the reader r at the beginning of the export data section of an underlying GC-created object/archive file by reading from it. The reader must be positioned at the start of the file before calling this function. The hdr result is the string before the export data, either "$$" or "$$B".

func FindPkg

func FindPkg(path, srcDir string) (filename, id string)

FindPkg returns the filename and unique package id for an import path based on package information provided by build.Import (using the build.Default build.Context). A relative srcDir is interpreted relative to the current working directory. If no file was found, an empty filename is returned.

func Import

func Import(packages map[string]*types.Package, path, srcDir string) (pkg *types.Package, err error)

Import imports a gc-generated package given its import path and srcDir, adds the corresponding package object to the packages map, and returns the object. The packages map must contain all packages already imported.

func ImportData

func ImportData(packages map[string]*types.Package, filename, id string, data io.Reader) (pkg *types.Package, err error)

ImportData imports a package by reading the gc-generated export data, adds the corresponding package object to the packages map indexed by id, and returns the object.

The packages map must contains all packages already imported. The data reader position must be the beginning of the export data section. The filename is only used in error messages.

If packages[id] contains the completely imported package, that package can be used directly, and there is no need to call this function (but there is also no harm but for extra time used).