new command hgpatch, for use by codereview extension

R=r
http://go/go-review/1018059

src/cmd/clean.bash

@@ -3,7 +3,7 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-for i in cc 6l 6a 6c 8l 8a 8c 8g 5l 5a 5c 5g gc 6g gopack nm cgo cov ebnflint godefs godoc gofmt prof gotest goyacc
+for i in cc 6l 6a 6c 8l 8a 8c 8g 5l 5a 5c 5g gc 6g gopack nm cgo cov ebnflint godefs godoc gofmt gotest goyacc hgpatch prof
 do
 	cd $i
 	make clean

src/cmd/hgpatch/Makefile

+# Copyright 2009 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.
+
+include $(GOROOT)/src/Make.$(GOARCH)
+
+TARG=hgpatch
+GOFILES=\
+	main.go\
+
+include $(GOROOT)/src/Make.cmd

src/cmd/hgpatch/doc.go

+// Copyright 2009 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.
+
+/*
+
+Hgpatch reads a patch, which should have been generated by
+a version control system like CVS, GIT, Mercurial, or Subversion,
+from a file (or standard input) and applies that patch to the local
+Mercurial repository.  If successful, it writes a list of affected
+files to standard output.
+
+Hgpatch is meant to be used by the Mercurial codereview extension.
+
+Usage:
+	hgpatch [patchfile]
+
+*/
+package documentation

src/cmd/hgpatch/main.go

+// Copyright 2009 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 (
+	"bytes";
+	"container/vector";
+	"exec";
+	"flag";
+	"fmt";
+	"io";
+	"os";
+	"patch";
+	"path";
+	"sort";
+	"strings";
+)
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: hgpatch [patchfile]\n");
+	os.Exit(2);
+}
+
+func main() {
+	flag.Usage = usage;
+	flag.Parse();
+
+	args := flag.Args();
+	var data []byte;
+	var err os.Error;
+	switch len(args) {
+	case 0:
+		data, err = io.ReadAll(os.Stdin);
+	case 1:
+		data, err = io.ReadFile(args[0]);
+	default:
+		usage();
+	}
+	chk(err);
+
+	pset, err := patch.Parse(data);
+	chk(err);
+
+	// Change to hg root directory, because
+	// patch paths are relative to root.
+	root, err := hgRoot();
+	chk(err);
+	chk(os.Chdir(root));
+
+	op, err := pset.Apply(io.ReadFile);
+	chk(err);
+
+	// Make sure there are no pending changes on the server.
+	if hgIncoming() {
+		fmt.Fprintf(os.Stderr, "incoming changes waiting; run hg sync first\n");
+		os.Exit(2);
+	}
+
+	// Make sure we won't be editing files with local pending changes.
+	dirtylist, err := hgModified();
+	chk(err);
+	dirty := make(map[string]int);
+	for _, f := range dirtylist {
+		dirty[f] = 1;
+	}
+	conflict := make(map[string]int);
+	for i := range op {
+		o := &op[i];
+		if o.Verb == patch.Delete || o.Verb == patch.Rename {
+			if _, ok := dirty[o.Src]; ok {
+				conflict[o.Src] = 1;
+			}
+		}
+		if o.Verb != patch.Delete {
+			if _, ok := dirty[o.Dst]; ok {
+				conflict[o.Dst] = 1;
+			}
+		}
+	}
+	if len(conflict) > 0 {
+		fmt.Fprintf(os.Stderr, "cannot apply patch to locally modified files:\n");
+		for name := range conflict {
+			fmt.Fprintf(os.Stderr, "\t%s\n", name);
+		}
+		os.Exit(2);
+	}
+
+	// Apply to local copy: order of commands matters.
+	// Accumulate undo log as we go, in case there is an error.
+	// Also accumulate list of modified files to print at end.
+	changed := make(map[string]int);
+
+	// Copy, Rename create the destination file, so they
+	// must happen before we write the data out.
+	// A single patch may have a Copy and a Rename
+	// with the same source, so we have to run all the
+	// Copy in one pass, then all the Rename.
+	for i := range op {
+		o := &op[i];
+		if o.Verb == patch.Copy {
+			makeParent(o.Dst);
+			chk(hgCopy(o.Dst, o.Src));
+			undoRevert(o.Dst);
+			changed[o.Dst] = 1;
+		}
+	}
+	for i := range op {
+		o := &op[i];
+		if o.Verb == patch.Rename {
+			makeParent(o.Dst);
+			chk(hgRename(o.Dst, o.Src));
+			undoRevert(o.Dst);
+			undoRevert(o.Src);
+			changed[o.Src] = 1;
+			changed[o.Dst] = 1;
+		}
+	}
+
+	// Run Delete before writing to files in case one of the
+	// deleted paths is becoming a directory.
+	for i := range op {
+		o := &op[i];
+		if o.Verb == patch.Delete {
+			chk(hgRemove(o.Src));
+			undoRevert(o.Src);
+			changed[o.Src] = 1;
+		}
+	}
+
+	// Write files.
+	for i := range op {
+		o := &op[i];
+		if o.Verb == patch.Delete {
+			continue;
+		}
+		if o.Verb == patch.Add {
+			makeParent(o.Dst);
+			changed[o.Dst] = 1;
+		}
+		if o.Data != nil {
+			chk(io.WriteFile(o.Dst, o.Data, 0644));
+			if o.Verb == patch.Add {
+				undoRm(o.Dst);
+			} else {
+				undoRevert(o.Dst);
+			}
+			changed[o.Dst] = 1;
+		}
+		if o.Mode != 0 {
+			chk(os.Chmod(o.Dst, o.Mode & 0755));
+			undoRevert(o.Dst);
+			changed[o.Dst] = 1;
+		}
+	}
+
+	// hg add looks at the destination file, so it must happen
+	// after we write the data out.
+	for i := range op {
+		o := &op[i];
+		if o.Verb == patch.Add {
+			chk(hgAdd(o.Dst));
+			undoRevert(o.Dst);
+			changed[o.Dst] = 1;
+		}
+	}
+
+	// Finished editing files.  Write the list of changed files to stdout.
+	list := make([]string, len(changed));
+	i := 0;
+	for f := range changed {
+		list[i] = f;
+		i++;
+	}
+	sort.SortStrings(list);
+	for _, f := range list {
+		fmt.Printf("%s\n", f);
+	}
+}
+
+
+// make parent directory for name, if necessary
+func makeParent(name string) {
+	parent, _ := path.Split(name);
+	chk(mkdirAll(parent, 0755));
+}
+
+// Copy of os.MkdirAll but adds to undo log after
+// creating a directory.
+func mkdirAll(path string, perm int) os.Error {
+	dir, err := os.Lstat(path);
+	if err == nil {
+		if dir.IsDirectory() {
+			return nil;
+		}
+		return &os.PathError{"mkdir", path, os.ENOTDIR};
+	}
+
+	i := len(path);
+	for i > 0 && path[i-1] == '/' {	// Skip trailing slashes.
+		i--;
+	}
+
+	j := i;
+	for j > 0 && path[j-1] != '/' {	// Scan backward over element.
+		j--;
+	}
+
+	if j > 0 {
+		err = mkdirAll(path[0 : j-1], perm);
+		if err != nil {
+			return err;
+		}
+	}
+
+	err = os.Mkdir(path, perm);
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(path);
+		if err1 == nil && dir.IsDirectory() {
+			return nil;
+		}
+		return err;
+	}
+	undoRm(path);
+	return nil;
+}
+
+// If err != nil, process the undo log and exit.
+func chk(err os.Error) {
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err);
+		runUndo();
+		os.Exit(2);
+	}
+}
+
+
+// Undo log
+type undo func() os.Error
+
+var undoLog vector.Vector	// vector of undo
+
+func undoRevert(name string) {
+	undoLog.Push(undo(func() os.Error { return hgRevert(name) }));
+}
+
+func undoRm(name string) {
+	undoLog.Push(undo(func() os.Error { return os.Remove(name) }));
+}
+
+func runUndo() {
+	for i := undoLog.Len() - 1; i >= 0; i-- {
+		if err := undoLog.At(i).(undo)(); err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", err);
+		}
+	}
+}
+
+
+// hgRoot returns the root directory of the repository.
+func hgRoot() (string, os.Error) {
+	out, err := run([]string{"hg", "root"}, nil);
+	if err != nil {
+		return "", err;
+	}
+	return strings.TrimSpace(out), nil;
+}
+
+// hgIncoming returns true if hg sync will pull in changes.
+func hgIncoming() bool {
+	// hg -q incoming exits 0 when there is nothing incoming, 1 otherwise.
+	_, err := run([]string{"hg", "-q", "incoming"}, nil);
+	return err == nil;
+}
+
+// hgModified returns a list of the modified files in the
+// repository.
+func hgModified() ([]string, os.Error) {
+	out, err := run([]string{"hg", "status", "-n"}, nil);
+	if err != nil {
+		return nil, err;
+	}
+	return strings.Split(strings.TrimSpace(out), "\n", 0), nil;
+}
+
+// hgAdd adds name to the repository.
+func hgAdd(name string) os.Error {
+	_, err := run([]string{"hg", "add", name}, nil);
+	return err;
+}
+
+// hgRemove removes name from the repository.
+func hgRemove(name string) os.Error {
+	_, err := run([]string{"hg", "rm", name}, nil);
+	return err;
+}
+
+// hgRevert reverts name.
+func hgRevert(name string) os.Error {
+	_, err := run([]string{"hg", "revert", name}, nil);
+	return err;
+}
+
+// hgCopy copies src to dst in the repository.
+// Note that the argument order matches io.Copy, not "hg cp".
+func hgCopy(dst, src string) os.Error {
+	_, err := run([]string{"hg", "cp", src, dst}, nil);
+	return err;
+}
+
+// hgRename renames src to dst in the repository.
+// Note that the argument order matches io.Copy, not "hg mv".
+func hgRename(dst, src string) os.Error {
+	_, err := run([]string{"hg", "mv", src, dst}, nil);
+	return err;
+}
+
+func copy(a []string) []string {
+	b := make([]string, len(a));
+	for i, s := range a {
+		b[i] = s;
+	}
+	return b;
+}
+
+var lookPathCache = make(map[string]string)
+
+// run runs the command argv, resolving argv[0] if necessary by searching $PATH.
+// It provides input on standard input to the command.
+func run(argv []string, input []byte) (out string, err os.Error) {
+	if len(argv) < 1 {
+		err = os.EINVAL;
+		goto Error;
+	}
+	prog, ok := lookPathCache[argv[0]];
+	if !ok {
+		prog, err = exec.LookPath(argv[0]);
+		if err != nil {
+			goto Error;
+		}
+		lookPathCache[argv[0]] = prog;
+	}
+	fmt.Fprintf(os.Stderr, "%v\n", argv);
+	var cmd *exec.Cmd;
+	if len(input) == 0 {
+		cmd, err = exec.Run(prog, argv, os.Environ(), exec.DevNull, exec.Pipe, exec.MergeWithStdout);
+		if err != nil {
+			goto Error;
+		}
+	} else {
+		cmd, err = exec.Run(prog, argv, os.Environ(), exec.Pipe, exec.Pipe, exec.MergeWithStdout);
+		if err != nil {
+			goto Error;
+		}
+		go func() {
+			cmd.Stdin.Write(input);
+			cmd.Stdin.Close();
+		}();
+	}
+	defer cmd.Close();
+	var buf bytes.Buffer;
+	_, err = io.Copy(&buf, cmd.Stdout);
+	out = buf.String();
+	if err != nil {
+		cmd.Wait(0);
+		goto Error;
+	}
+	w, err := cmd.Wait(0);
+	if err != nil {
+		goto Error;
+	}
+	if !w.Exited() || w.ExitStatus() != 0 {
+		err = w;
+		goto Error;
+	}
+	return;
+
+Error:
+	err = &runError{copy(argv), err};
+	return;
+}
+
+// A runError represents an error that occurred while running a command.
+type runError struct {
+	cmd	[]string;
+	err	os.Error;
+}
+
+func (e *runError) String() string {
+	return strings.Join(e.cmd, " ") + ": " + e.err.String();
+}

src/make.bash

@@ -20,7 +20,7 @@ CC=${CC:-gcc}
 sed -e "s|@CC@|$CC|" < quietgcc.bash > $GOBIN/quietgcc
 chmod +x $GOBIN/quietgcc
 
-for i in lib9 libbio libmach cmd pkg libcgo cmd/cgo cmd/ebnflint cmd/godoc cmd/gofmt cmd/goyacc
+for i in lib9 libbio libmach cmd pkg libcgo cmd/cgo cmd/ebnflint cmd/godoc cmd/gofmt cmd/goyacc cmd/hgpatch
 do
 	case "$i-$GOOS" in
 	libcgo-nacl)