gofix: add go1pkgrename

This will do the package import renamings for Go 1.

R=rsc, r, dsymonds
CC=golang-dev
https://golang.org/cl/5316078

src/cmd/gofix/Makefile

@@ -9,6 +9,7 @@ GOFILES=\
 	error.go\
 	filepath.go\
 	fix.go\
+	go1pkgrename.go\
 	htmlerr.go\
 	httpfinalurl.go\
 	httpfs.go\

src/cmd/gofix/go1pkgrename.go

@@ -0,0 +1,93 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"go/ast"
+)
+
+func init() {
+	register(go1pkgrenameFix)
+}
+
+var go1pkgrenameFix = fix{
+	"go1rename",
+	"2011-11-08",
+	go1pkgrename,
+	`Rewrite imports for packages moved during transition to Go 1.
+
+http://codereview.appspot.com/5316078
+`,
+}
+
+var go1PackageRenames = []struct{ old, new string }{
+	{"asn1", "encoding/asn1"},
+	{"big", "math/big"},
+	{"cmath", "math/cmplx"},
+	{"csv", "encoding/csv"},
+	{"exec", "os/exec"},
+	{"exp/template/html", "html/template"},
+	{"gob", "encoding/gob"},
+	{"http", "net/http"},
+	{"http/cgi", "net/http/cgi"},
+	{"http/fcgi", "net/http/fcgi"},
+	{"http/httptest", "net/http/httptest"},
+	{"http/pprof", "net/http/pprof"},
+	{"json", "encoding/json"},
+	{"mail", "net/mail"},
+	{"rpc", "net/rpc"},
+	{"rpc/jsonrpc", "net/rpc/jsonrpc"},
+	{"scanner", "text/scanner"},
+	{"smtp", "net/smtp"},
+	{"syslog", "log/syslog"},
+	{"tabwriter", "text/tabwriter"},
+	{"template", "text/template"},
+	{"template/parse", "text/template/parse"},
+	{"rand", "math/rand"},
+	{"url", "net/url"},
+	{"utf16", "unicode/utf16"},
+	{"utf8", "unicode/utf8"},
+	{"xml", "encoding/xml"},
+}
+
+var go1PackageNameRenames = []struct{ newPath, old, new string }{
+	{"html/template", "html", "template"},
+	{"math/cmplx", "cmath", "cmplx"},
+}
+
+func go1pkgrename(f *ast.File) bool {
+	fixed := false
+
+	// First update the imports.
+	for _, rename := range go1PackageRenames {
+		if !imports(f, rename.old) {
+			continue
+		}
+		if rewriteImport(f, rename.old, rename.new) {
+			fixed = true
+		}
+	}
+	if !fixed {
+		return false
+	}
+
+	// Now update the package names used by importers.
+	for _, rename := range go1PackageNameRenames {
+		// These are rare packages, so do the import test before walking.
+		if imports(f, rename.newPath) {
+			walk(f, func(n interface{}) {
+				if sel, ok := n.(*ast.SelectorExpr); ok {
+					if isTopName(sel.X, rename.old) {
+						// We know Sel.X is an Ident.
+						sel.X.(*ast.Ident).Name = rename.new
+						return
+					}
+				}
+			})
+		}
+	}
+
+	return fixed
+}

src/cmd/gofix/go1pkgrename_test.go

@@ -0,0 +1,98 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+func init() {
+	addTestCases(go1renameTests, go1pkgrename)
+}
+
+var go1renameTests = []testCase{
+	{
+		Name: "go1rename.0",
+		In: `package main
+
+import (
+	"asn1"
+	"big"
+	"cmath"
+	"csv"
+	"exec"
+	"exp/template/html"
+	"gob"
+	"http"
+	"http/cgi"
+	"http/fcgi"
+	"http/httptest"
+	"http/pprof"
+	"json"
+	"mail"
+	"rand"
+	"rpc"
+	"rpc/jsonrpc"
+	"scanner"
+	"smtp"
+	"syslog"
+	"tabwriter"
+	"template"
+	"template/parse"
+	"url"
+	"utf16"
+	"utf8"
+	"xml"
+)
+`,
+		Out: `package main
+
+import (
+	"encoding/asn1"
+	"encoding/csv"
+	"encoding/gob"
+	"encoding/json"
+	"encoding/xml"
+	"html/template"
+	"log/syslog"
+	"math/big"
+	"math/cmplx"
+	"math/rand"
+	"net/http"
+	"net/http/cgi"
+	"net/http/fcgi"
+	"net/http/httptest"
+	"net/http/pprof"
+	"net/mail"
+	"net/rpc"
+	"net/rpc/jsonrpc"
+	"net/smtp"
+	"net/url"
+	"os/exec"
+	"text/scanner"
+	"text/tabwriter"
+	"text/template"
+	"text/template/parse"
+	"unicode/utf16"
+	"unicode/utf8"
+)
+`,
+	},
+	{
+		Name: "go1rename.1",
+		In: `package main
+
+import "cmath"
+import poot "exp/template/html"
+
+var _ = cmath.Sin
+var _ = poot.Poot
+`,
+		Out: `package main
+
+import "math/cmplx"
+import poot "html/template"
+
+var _ = cmplx.Sin
+var _ = poot.Poot
+`,
+	},
+}