From: Tim King <taking@google.com>
Date: Fri, 8 Nov 2024 23:07:51 +0000 (-0800)
Subject: cmd/compile/internal/importer: minimize Import differences
X-Git-Tag: go1.24rc1~390
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=c79a486be20b395bdd198be9112e633623665988;p=gostls13.git

cmd/compile/internal/importer: minimize Import differences

Minimizes the differences with go/internal/gcimporter.Import.

Note that the copy in cmd/compile/internal/importer is currently
only used in tests.

The delta between the two Import functions is now just types vs types2.

Change-Id: I5e94d3aa5bbdb78252e47310c95807f63e27ef3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/626698
Commit-Queue: Tim King <taking@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---

diff --git a/src/cmd/compile/internal/importer/gcimporter.go b/src/cmd/compile/internal/importer/gcimporter.go
index 47a0d7c0bf..fa780d386a 100644
--- a/src/cmd/compile/internal/importer/gcimporter.go
+++ b/src/cmd/compile/internal/importer/gcimporter.go
@@ -14,6 +14,7 @@ import (
 	"fmt"
 	"go/build"
 	"internal/pkgbits"
+	"internal/saferio"
 	"io"
 	"os"
 	"os/exec"
@@ -216,23 +217,11 @@ func Import(packages map[string]*types2.Package, path, srcDir string, lookup fun
 		err = fmt.Errorf("import %q: old textual export format no longer supported (recompile package)", path)
 
 	case "$$B\n":
-		// TODO(taking): minimize code delta with src/go/internal/gcimporter.Import.
-		var data []byte
-		var r io.Reader = buf
-		if size >= 0 {
-			r = io.LimitReader(r, int64(size))
-		}
-		data, err = io.ReadAll(r)
-		if err != nil {
-			break
-		}
-
-		if len(data) == 0 {
-			err = fmt.Errorf("import %q: missing export data", path)
-			break
+		var exportFormat byte
+		if exportFormat, err = buf.ReadByte(); err != nil {
+			return
 		}
-		exportFormat := data[0]
-		s := string(data[1:])
+		size--
 
 		// The unified export format starts with a 'u'; the indexed export
 		// format starts with an 'i'; and the older binary export format
@@ -241,7 +230,18 @@ func Import(packages map[string]*types2.Package, path, srcDir string, lookup fun
 		switch exportFormat {
 		case 'u':
 			// exported strings may contain "\n$$\n" - search backwards
+			var data []byte
+			var r io.Reader = buf
+			if size >= 0 {
+				if data, err = saferio.ReadData(r, uint64(size)); err != nil {
+					return
+				}
+			} else if data, err = io.ReadAll(r); err != nil {
+				return
+			}
+			s := string(data)
 			s = s[:strings.LastIndex(s, "\n$$\n")]
+
 			input := pkgbits.NewPkgDecoder(id, s)
 			pkg = ReadPackage(nil, packages, input)
 		default:
diff --git a/src/go/internal/gcimporter/gcimporter.go b/src/go/internal/gcimporter/gcimporter.go
index f86b20da8d..a07fd8a6de 100644
--- a/src/go/internal/gcimporter/gcimporter.go
+++ b/src/go/internal/gcimporter/gcimporter.go
@@ -23,9 +23,6 @@ import (
 	"sync"
 )
 
-// debugging/development support
-const debug = false
-
 var exportMap sync.Map // package dir → func() (string, error)
 
 // lookupGorootExport returns the location of the export data