diff options
Diffstat (limited to 'vendor/golang.org/x/tools/go/gcexportdata')
| -rw-r--r-- | vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go | 32 |
1 files changed, 21 insertions, 11 deletions
diff --git a/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go b/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go index 2ed25a75..165ede0f 100644 --- a/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go +++ b/vendor/golang.org/x/tools/go/gcexportdata/gcexportdata.go @@ -27,10 +27,9 @@ import ( "go/token" "go/types" "io" - "io/ioutil" "os/exec" - "golang.org/x/tools/go/internal/gcimporter" + "golang.org/x/tools/internal/gcimporter" ) // Find returns the name of an object (.o) or archive (.a) file @@ -85,9 +84,26 @@ func NewReader(r io.Reader) (io.Reader, error) { } } +// readAll works the same way as io.ReadAll, but avoids allocations and copies +// by preallocating a byte slice of the necessary size if the size is known up +// front. This is always possible when the input is an archive. In that case, +// NewReader will return the known size using an io.LimitedReader. +func readAll(r io.Reader) ([]byte, error) { + if lr, ok := r.(*io.LimitedReader); ok { + data := make([]byte, lr.N) + _, err := io.ReadFull(lr, data) + return data, err + } + return io.ReadAll(r) +} + // Read reads export data from in, decodes it, and returns type // information for the package. -// The package name is specified by path. +// +// The package path (effectively its linker symbol prefix) is +// specified by path, since unlike the package name, this information +// may not be recorded in the export data. +// // File position information is added to fset. // // Read may inspect and add to the imports map to ensure that references @@ -98,7 +114,7 @@ func NewReader(r io.Reader) (io.Reader, error) { // // 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) + data, err := readAll(in) if err != nil { return nil, fmt.Errorf("reading export data for %q: %v", path, err) } @@ -107,12 +123,6 @@ func Read(in io.Reader, fset *token.FileSet, imports map[string]*types.Package, return nil, fmt.Errorf("can't read export data for %q directly from an archive file (call gcexportdata.NewReader first to extract export data)", path) } - // 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)) - } - // The indexed export format starts with an 'i'; the older // binary export format starts with a 'c', 'd', or 'v' // (from "version"). Select appropriate importer. @@ -161,7 +171,7 @@ func Write(out io.Writer, fset *token.FileSet, pkg *types.Package) error { // // Experimental: This API is experimental and may change in the future. func ReadBundle(in io.Reader, fset *token.FileSet, imports map[string]*types.Package) ([]*types.Package, error) { - data, err := ioutil.ReadAll(in) + data, err := readAll(in) if err != nil { return nil, fmt.Errorf("reading export bundle: %v", err) } |