3 files changed, 387 insertions, 0 deletions
diff --git a/src/cmd/hgpatch/Makefile b/src/cmd/hgpatch/Makefile
new file mode 100644
index 000000000..1ef98d7f9
--- /dev/null
+++ b/src/cmd/hgpatch/Makefile
@@ -0,0 +1,11 @@
+# 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 ../../Make.inc
+
+TARG=hgpatch
+GOFILES=\
+	main.go\
+
+include ../../Make.cmd
diff --git a/src/cmd/hgpatch/doc.go b/src/cmd/hgpatch/doc.go
new file mode 100644
index 000000000..1e0f1da38
--- /dev/null
+++ b/src/cmd/hgpatch/doc.go
@@ -0,0 +1,18 @@
+// 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 applies a patch to the local Mercurial repository.
+The patch should have been been generated by
+a version control system like CVS, Git, Mercurial, or Subversion.
+If successful, hgpatch 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
diff --git a/src/cmd/hgpatch/main.go b/src/cmd/hgpatch/main.go
new file mode 100644
index 000000000..9e338abcb
--- /dev/null
+++ b/src/cmd/hgpatch/main.go
@@ -0,0 +1,358 @@
+// 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/ioutil"
+	"os"
+	"patch"
+	"path/filepath"
+	"sort"
+	"strings"
+)
+
+var checkSync = flag.Bool("checksync", true, "check whether repository is out of sync")
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "usage: hgpatch [options] [patchfile]\n")
+	flag.PrintDefaults()
+	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 = ioutil.ReadAll(os.Stdin)
+	case 1:
+		data, err = ioutil.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))
+
+	// Make sure there are no pending changes on the server.
+	if *checkSync && 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]bool)
+	for _, f := range dirtylist {
+		dirty[f] = true
+	}
+	conflict := make(map[string]bool)
+	for _, f := range pset.File {
+		if f.Verb == patch.Delete || f.Verb == patch.Rename {
+			if dirty[f.Src] {
+				conflict[f.Src] = true
+			}
+		}
+		if f.Verb != patch.Delete {
+			if dirty[f.Dst] {
+				conflict[f.Dst] = true
+			}
+		}
+	}
+	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 changes in memory.
+	op, err := pset.Apply(ioutil.ReadFile)
+	chk(err)
+
+	// Write changes to disk 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(ioutil.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, uint32(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.Strings(list)
+	for _, f := range list {
+		fmt.Printf("%s\n", f)
+	}
+}
+
+// make parent directory for name, if necessary
+func makeParent(name string) {
+	parent, _ := filepath.Split(name)
+	chk(mkdirAll(parent, 0755))
+}
+
+// Copy of os.MkdirAll but adds to undo log after
+// creating a directory.
+func mkdirAll(path string, perm uint32) 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"), 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 dup(a []string) []string {
+	b := make([]string, len(a))
+	copy(b, a)
+	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 {
+		return "", &runError{dup(argv), os.EINVAL}
+	}
+
+	prog, ok := lookPathCache[argv[0]]
+	if !ok {
+		prog, err = exec.LookPath(argv[0])
+		if err != nil {
+			return "", &runError{dup(argv), err}
+		}
+		lookPathCache[argv[0]] = prog
+	}
+
+	cmd := exec.Command(prog, argv[1:]...)
+	if len(input) > 0 {
+		cmd.Stdin = bytes.NewBuffer(input)
+	}
+	bs, err := cmd.CombinedOutput()
+	if err != nil {
+		return "", &runError{dup(argv), err}
+	}
+	return string(bs), nil
+}
+
+// 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() }