// Read reads export data from in, decodes it, and returns type
// information for the package.
// The package name is specified by path.
// File position information is added to fset.
//
// Read may inspect and add to the imports map to ensure that references
// within the export data to other packages are consistent. The caller
// must ensure that imports[path] does not exist, or exists but is
// incomplete (see types.Package.Complete), and Read inserts the
// resulting package into this map entry.
//
// On return, the state of the reader is undefined.
func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package, path string) (*types.Package, error) {
data, err := ioutil.ReadAll(in)
if err != nil {
return nil, fmt.Errorf("reading export data for %q: %v", path, err)
}
// The App Engine Go runtime v1.6 uses the old export data format.
// TODO(adonovan): delete once v1.7 has been around for a while.
if bytes.HasPrefix(data, []byte("package ")) {
return gcimporter.ImportData(imports, path, path, bytes.NewReader(data))
}
_, pkg, err := gcimporter.BImportData(fset, imports, data, path)
return pkg, err
}
// Resolve resolves the package information for unit and its dependencies. On
// success the package corresponding to unit is located via ImportPath in the
// Packages map of the returned value.
//
// If info != nil, it is used to populate the Info field of the return value
// and will contain the output of the type checker in each user-provided map
// field.
func Resolve(unit *apb.CompilationUnit, f Fetcher, info *types.Info) (*PackageInfo, error) {
isSource := make(map[string]bool)
for _, src := range unit.SourceFile {
isSource[src] = true
}
deps := make(map[string]*types.Package) // import path → package
imap := make(map[string]*spb.VName) // import path → vname
srcs := make(map[string]string) // file path → text
fset := token.NewFileSet() // location info for the parser
var files []*ast.File // parsed sources
// Classify the required inputs as either sources, which are to be parsed,
// or dependencies, which are to be "imported" via the type-checker's
// import mechanism. If successful, this populates fset and files with the
// lexical and syntactic content of the package's own sources.
for _, ri := range unit.RequiredInput {
if ri.Info == nil {
return nil, errors.New("required input file info missing")
}
// Fetch the contents of each required input.
fpath := ri.Info.Path
data, err := f.Fetch(fpath, ri.Info.Digest)
if err != nil {
return nil, fmt.Errorf("fetching %q (%s): %v", fpath, ri.Info.Digest, err)
}
// Source inputs need to be parsed, so we can give their ASTs to the
// type checker later on.
if isSource[fpath] {
srcs[fpath] = string(data)
parsed, err := parser.ParseFile(fset, fpath, data, parser.AllErrors)
if err != nil {
return nil, fmt.Errorf("parsing %q: %v", fpath, err)
}
files = append(files, parsed)
continue
}
// For archives, recover the import path from the VName and read the
// archive header for type information. If the VName is not set, the
// import is considered bogus.
if ri.VName == nil {
return nil, fmt.Errorf("missing vname for %q", fpath)
}
hdr := bufio.NewReader(bytes.NewReader(data))
if _, err := gcimporter.FindExportData(hdr); err != nil {
return nil, fmt.Errorf("scanning export data in %q: %v", fpath, err)
}
ipath := path.Join(ri.VName.Corpus, ri.VName.Path)
if govname.IsStandardLibrary(ri.VName) {
ipath = ri.VName.Path
}
imap[ipath] = ri.VName
if _, err := gcimporter.ImportData(deps, fpath, ipath, hdr); err != nil {
return nil, fmt.Errorf("importing %q: %v", ipath, err)
}
}
// Fill in the mapping from packages to vnames.
vmap := make(map[*types.Package]*spb.VName)
for ip, vname := range imap {
if pkg := deps[ip]; pkg != nil {
vmap[pkg] = vname
}
}
pi := &PackageInfo{
Name: files[0].Name.Name,
ImportPath: path.Join(unit.VName.Corpus, unit.VName.Path),
VNames: vmap,
FileSet: fset,
Files: files,
SourceText: srcs,
Dependencies: deps,
Info: info,
sigs: make(map[types.Object]string),
}
// Run the type-checker and collect any errors it generates. Errors in the
// type checker are not returned directly; the caller can read them from
// the Errors field.
c := &types.Config{
FakeImportC: true, // so we can handle cgo
DisableUnusedImportCheck: true, // this is not fatal to type-checking
Importer: pi,
Error: func(err error) {
pi.Errors = append(pi.Errors, err)
},
}
if pkg, _ := c.Check(pi.Name, pi.FileSet, pi.Files, pi.Info); pkg != nil {
pi.Package = pkg
vmap[pkg] = unit.VName
}
return pi, nil
}