Index: common/archive/ar/writer.go |
diff --git a/common/archive/ar/writer.go b/common/archive/ar/writer.go |
new file mode 100644 |
index 0000000000000000000000000000000000000000..de042eb7ec2a97ec1c8db3706f606cde52c233f9 |
--- /dev/null |
+++ b/common/archive/ar/writer.go |
@@ -0,0 +1,221 @@ |
+// Copyright 2016 The LUCI Authors. All rights reserved. |
+// Use of this source code is governed under the Apache License, Version 2.0 |
+// that can be found in the LICENSE file. |
+ |
+// Write an ar archive file with BSD style filenames. |
+ |
+package ar |
+ |
+import ( |
+ "errors" |
+ "fmt" |
+ "io" |
+ "os" |
+) |
+ |
+const DEFAULT_MODTIME = 1447140471 |
+const DEFAULT_USER = 1000 |
+const DEFAULT_GROUP = 1000 |
+const DEFAULT_MODE = 0100640 // 100640 -- Octal |
+ |
+type WriterStage uint |
+ |
+const ( |
+ WRITE_HEADER WriterStage = iota |
+ WRITE_BODY |
+ WRITE_CLOSED |
+) |
+ |
+type Writer struct { |
+ w io.Writer |
+ stage WriterStage |
+ |
+ bytesrequired int64 |
+ needspadding bool |
+} |
+ |
+func NewWriter(w io.Writer) *Writer { |
+ io.WriteString(w, "!<arch>\n") |
+ return &Writer{w: w, stage: WRITE_HEADER, bytesrequired: 0, needspadding: false} |
+} |
+ |
+func (aw *Writer) Close() error { |
+ switch aw.stage { |
+ case WRITE_HEADER: |
+ // Good |
+ case WRITE_BODY: |
+ return errors.New("Usage error, writing a file.") |
+ case WRITE_CLOSED: |
+ return errors.New("Usage error, archive already closed.") |
+ default: |
+ panic(fmt.Sprintf("Unknown writer mode: %d", aw.stage)) |
+ } |
+ //aw.w.Close() |
+ aw.stage = WRITE_CLOSED |
+ return nil |
+} |
+ |
+func (aw *Writer) wroteBytes(numbytes int64) error { |
+ if numbytes > aw.bytesrequired { |
+ panic(fmt.Sprintf("To much data written! Needed %d, got %d", aw.bytesrequired, numbytes)) |
+ } |
+ |
+ aw.bytesrequired -= numbytes |
+ if aw.bytesrequired != 0 { |
+ return nil |
+ } |
+ |
+ // Padding to 16bit boundary |
+ if aw.needspadding { |
+ io.WriteString(aw.w, "\n") |
+ aw.needspadding = false |
+ } |
+ aw.stage = WRITE_HEADER |
+ return nil |
+} |
+ |
+// Check you can write bytes to the ar at this moment. |
+func (aw *Writer) checkWrite() error { |
+ switch aw.stage { |
+ case WRITE_HEADER: |
+ return errors.New("Usage error, need to write header first.") |
+ // Good |
+ case WRITE_BODY: |
+ return nil |
+ case WRITE_CLOSED: |
+ return errors.New("Usage error, archive closed.") |
+ default: |
+ panic(fmt.Sprintf("Unknown writer mode: %d", aw.stage)) |
+ } |
+} |
+ |
+// Check we have finished writing bytes |
+func (aw *Writer) checkFinished() { |
+ if aw.bytesrequired != 0 { |
+ panic(fmt.Sprintf("Didn't write enough bytes %d still needed, archive corrupted!", aw.bytesrequired)) |
+ } |
+} |
+ |
+func (aw *Writer) writePartial(data []byte) error { |
+ err := aw.checkWrite() |
+ if err != nil { |
+ return err |
+ } |
+ |
+ datalen := int64(len(data)) |
+ if datalen > aw.bytesrequired { |
+ return errors.New(fmt.Sprintf("To much data! Needed %d, got %d", aw.bytesrequired, datalen)) |
+ } |
+ |
+ aw.w.Write(data) |
+ aw.wroteBytes(datalen) |
+ return nil |
+} |
+ |
+func (aw *Writer) WriteReader(data io.Reader) error { |
+ err := aw.checkWrite() |
+ if err != nil { |
+ return err |
+ } |
+ |
+ count, err := io.Copy(aw.w, data) |
+ if err != nil { |
+ panic(fmt.Sprintf("err while copying (%s), archive is probably corrupted!", err)) |
+ } |
+ aw.wroteBytes(count) |
+ aw.checkFinished() |
+ |
+ return nil |
+} |
+ |
+func (aw *Writer) WriteBytes(data []byte) error { |
+ err := aw.checkWrite() |
+ if err != nil { |
+ return err |
+ } |
+ |
+ datalen := int64(len(data)) |
+ if datalen != aw.bytesrequired { |
+ return errors.New(fmt.Sprintf("Wrong amount of data! Needed %d, got %d", aw.bytesrequired, datalen)) |
+ } |
+ |
+ aw.writePartial(data) |
+ aw.checkFinished() |
+ return nil |
+} |
+ |
+func (aw *Writer) writeHeaderBytes(name string, size int64, modtime uint64, ownerid uint, groupid uint, filemod uint) error { |
+ switch aw.stage { |
+ case WRITE_HEADER: |
+ // Good |
+ case WRITE_BODY: |
+ return errors.New("Usage error, already writing a file.") |
+ case WRITE_CLOSED: |
+ return errors.New("Usage error, archive closed.") |
+ default: |
+ panic(fmt.Sprintf("Unknown writer mode: %d", aw.stage)) |
+ } |
+ |
+ // File name length prefixed with '#1/' (BSD variant), 16 bytes |
+ fmt.Fprintf(aw.w, "#1/%-13d", len(name)) |
+ |
+ // Modtime, 12 bytes |
+ fmt.Fprintf(aw.w, "%-12d", modtime) |
+ |
+ // Owner ID, 6 bytes |
+ fmt.Fprintf(aw.w, "%-6d", ownerid) |
+ |
+ // Group ID, 6 bytes |
+ fmt.Fprintf(aw.w, "%-6d", groupid) |
+ |
+ // File mode, 8 bytes |
+ fmt.Fprintf(aw.w, "%-8o", filemod) |
+ |
+ // In BSD variant, file size includes the filename length |
+ aw.bytesrequired = int64(len(name)) + size |
+ |
+ // File size, 10 bytes |
+ fmt.Fprintf(aw.w, "%-10d", aw.bytesrequired) |
+ |
+ // File magic, 2 bytes |
+ io.WriteString(aw.w, "\x60\n") |
+ |
+ aw.stage = WRITE_BODY |
+ aw.needspadding = (aw.bytesrequired%2 != 0) |
+ |
+ // Filename - BSD variant |
+ return aw.writePartial([]byte(name)) |
+} |
+ |
+func (aw *Writer) WriteHeaderDefault(name string, size int64) error { |
+ return aw.writeHeaderBytes(name, size, 1447140471, DEFAULT_USER, DEFAULT_GROUP, DEFAULT_MODE) |
+} |
+ |
+func (aw *Writer) WriteHeader(stat os.FileInfo) error { |
+ if stat.IsDir() { |
+ return errors.New("Only work with files, not directories.") |
+ } |
+ |
+ mode := stat.Mode() |
+ if mode&os.ModeSymlink == os.ModeSymlink { |
+ return errors.New("Only work with files, not symlinks.") |
+ } |
+ |
+ /* FIXME: Should we also exclude other "special" files? |
+ if (stat.Mode().ModeType != 0) { |
+ return &argError{stat, "Only work with plain files."} |
+ } |
+ */ |
+ |
+ // FIXME: Where do we get user/group from - they don't appear to be in Go's Mode() object? |
+ return aw.writeHeaderBytes(stat.Name(), stat.Size(), uint64(stat.ModTime().Unix()), DEFAULT_USER, DEFAULT_GROUP, uint(mode&os.ModePerm)) |
+} |
+ |
+func (aw *Writer) Add(name string, data []byte) error { |
+ err := aw.WriteHeaderDefault(name, int64(len(data))) |
+ if err != nil { |
+ return err |
+ } |
+ |
+ return aw.WriteBytes(data) |
+} |