diff options
Diffstat (limited to 'go/gcexportdata/gcexportdata.go')
| -rw-r--r-- | go/gcexportdata/gcexportdata.go | 81 |
1 files changed, 61 insertions, 20 deletions
diff --git a/go/gcexportdata/gcexportdata.go b/go/gcexportdata/gcexportdata.go index cec819d64..165ede0f8 100644 --- a/go/gcexportdata/gcexportdata.go +++ b/go/gcexportdata/gcexportdata.go @@ -17,32 +17,46 @@ // developer tools, which will then be able to consume both Go 1.7 and // Go 1.8 export data files, so they will work before and after the // Go update. (See discussion at https://golang.org/issue/15651.) -// package gcexportdata // import "golang.org/x/tools/go/gcexportdata" import ( "bufio" "bytes" + "encoding/json" "fmt" "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 // containing type information for the specified import path, -// using the workspace layout conventions of go/build. +// using the go command. // If no file was found, an empty filename is returned. // // A relative srcDir is interpreted relative to the current working directory. // // Find also returns the package's resolved (canonical) import path, // reflecting the effects of srcDir and vendoring on importPath. +// +// Deprecated: Use the higher-level API in golang.org/x/tools/go/packages, +// which is more efficient. func Find(importPath, srcDir string) (filename, path string) { - return gcimporter.FindPkg(importPath, srcDir) + cmd := exec.Command("go", "list", "-json", "-export", "--", importPath) + cmd.Dir = srcDir + out, err := cmd.CombinedOutput() + if err != nil { + return "", "" + } + var data struct { + ImportPath string + Export string + } + json.Unmarshal(out, &data) + return data.Export, data.ImportPath } // NewReader returns a reader for the export data section of an object @@ -70,9 +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 @@ -83,7 +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) } @@ -92,22 +123,32 @@ 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. - if len(data) > 0 && data[0] == 'i' { - _, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path) - return pkg, err - } + if len(data) > 0 { + switch data[0] { + case 'i': + _, pkg, err := gcimporter.IImportData(fset, imports, data[1:], path) + return pkg, err + + case 'v', 'c', 'd': + _, pkg, err := gcimporter.BImportData(fset, imports, data, path) + return pkg, err - _, pkg, err := gcimporter.BImportData(fset, imports, data, path) - return pkg, err + case 'u': + _, pkg, err := gcimporter.UImportData(fset, imports, data[1:], path) + return pkg, err + + default: + l := len(data) + if l > 10 { + l = 10 + } + return nil, fmt.Errorf("unexpected export data with prefix %q for path %s", string(data[:l]), path) + } + } + return nil, fmt.Errorf("empty export data for %s", path) } // Write writes encoded type information for the specified package to out. @@ -130,7 +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) } |