go/internal/gcimporter,cmd/compile/internal/importer: reuse archive.ReadHeader

Reuse (or copy) cmd/internal/archive.ReadHeader in importers.

Change-Id: I3caa19b1b366c2bbffcdeb0ef4db337ee457b47e
Reviewed-on: https://go-review.googlesource.com/c/go/+/626776
Commit-Queue: Tim King <taking@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Robert Griesemer <gri@google.com>

diff --git a/src/cmd/compile/internal/importer/exportdata.go b/src/cmd/compile/internal/importer/exportdata.go
index 2ae8c1b4d96da43776ec2516a1563330d98af307..8536440ade6d57a2de4ecbf18d9459b77e18f1aa 100644 (file)
--- a/src/cmd/compile/internal/importer/exportdata.go
+++ b/src/cmd/compile/internal/importer/exportdata.go
@@ -8,35 +8,11 @@ package importer
 
 import (
        "bufio"
+       "cmd/internal/archive"
        "fmt"
-       "io"
-       "strconv"
        "strings"
 )
 
-func readGopackHeader(r *bufio.Reader) (name string, size int, err error) {
-       // TODO(taking): replace with src/cmd/internal/archive.ReadHeader.
-
-       // See $GOROOT/include/ar.h.
-       hdr := make([]byte, 16+12+6+6+8+10+2)
-       _, err = io.ReadFull(r, hdr)
-       if err != nil {
-               return
-       }
-       // leave for debugging
-       if false {
-               fmt.Printf("header: %s", hdr)
-       }
-       s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
-       size, err = strconv.Atoi(s)
-       if err != nil || hdr[len(hdr)-2] != '`' || hdr[len(hdr)-1] != '\n' {
-               err = fmt.Errorf("invalid archive header")
-               return
-       }
-       name = strings.TrimSpace(string(hdr[:16]))
-       return
-}
-
 // 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
@@ -64,15 +40,10 @@ func FindExportData(r *bufio.Reader) (hdr string, size int, err error) {
                return
        }
 
-       // Archive file. Scan to __.PKGDEF.
-       var name string
-       if name, size, err = readGopackHeader(r); err != nil {
-               return
-       }
-
-       // First entry should be __.PKGDEF.
-       if name != "__.PKGDEF" {
-               err = fmt.Errorf("go archive is missing __.PKGDEF")
+       // package export block should be first
+       size = archive.ReadHeader(r, "__.PKGDEF")
+       if size <= 0 {
+               err = fmt.Errorf("not a package file")
                return
        }
 

diff --git a/src/go/internal/gcimporter/exportdata.go b/src/go/internal/gcimporter/exportdata.go
index ec17c1dd1a9b02647a0c81eaf82c125aa60b0940..a022c153ecc9b655f7215c60604188cbd66d2122 100644 (file)
--- a/src/go/internal/gcimporter/exportdata.go
+++ b/src/go/internal/gcimporter/exportdata.go
@@ -14,25 +14,22 @@ import (
        "strings"
 )
 
-func readGopackHeader(r *bufio.Reader) (name string, size int, err error) {
-       // See $GOROOT/include/ar.h.
-       hdr := make([]byte, 16+12+6+6+8+10+2)
-       _, err = io.ReadFull(r, hdr)
-       if err != nil {
-               return
-       }
-       // leave for debugging
-       if false {
-               fmt.Printf("header: %s", hdr)
+// Copy of cmd/internal/archive.ReadHeader.
+func readArchiveHeader(b *bufio.Reader, name string) int {
+       // architecture-independent object file output
+       const HeaderSize = 60
+
+       var buf [HeaderSize]byte
+       if _, err := io.ReadFull(b, buf[:]); err != nil {
+               return -1
        }
-       s := strings.TrimSpace(string(hdr[16+12+6+6+8:][:10]))
-       size, err = strconv.Atoi(s)
-       if err != nil || hdr[len(hdr)-2] != '`' || hdr[len(hdr)-1] != '\n' {
-               err = fmt.Errorf("invalid archive header")
-               return
+       aname := strings.Trim(string(buf[0:16]), " ")
+       if !strings.HasPrefix(aname, name) {
+               return -1
        }
-       name = strings.TrimSpace(string(hdr[:16]))
-       return
+       asize := strings.Trim(string(buf[48:58]), " ")
+       i, _ := strconv.Atoi(asize)
+       return i
 }
 
 // FindExportData positions the reader r at the beginning of the
@@ -54,15 +51,10 @@ func FindExportData(r *bufio.Reader) (hdr string, size int, err error) {
                return
        }
 
-       // Archive file. Scan to __.PKGDEF.
-       var name string
-       if name, size, err = readGopackHeader(r); err != nil {
-               return
-       }
-
-       // First entry should be __.PKGDEF.
-       if name != "__.PKGDEF" {
-               err = fmt.Errorf("go archive is missing __.PKGDEF")
+       // package export block should be first
+       size = readArchiveHeader(r, "__.PKGDEF")
+       if size <= 0 {
+               err = fmt.Errorf("not a package file")
                return
        }