From e4d936b5ed4cf6ed8ac383ac3ea81e0ed4c51505 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Fri, 17 Mar 2023 21:25:07 +0530
Subject: [PATCH] More work on porting the diff kitten

---
 tools/cmd/diff/collect.go | 258 ++++++++++++++++++++++++++++++++++++--
 tools/cmd/diff/main.go    |  70 ++++++++++-
 tools/utils/tar.go        | 101 +++++++++++++++
 3 files changed, 416 insertions(+), 13 deletions(-)
 create mode 100644 tools/utils/tar.go

diff --git a/tools/cmd/diff/collect.go b/tools/cmd/diff/collect.go
index 787d35168..6568b99c5 100644
--- a/tools/cmd/diff/collect.go
+++ b/tools/cmd/diff/collect.go
@@ -3,23 +3,43 @@
 package diff
 
 import (
+	"crypto/md5"
 	"fmt"
+	"io/fs"
 	"kitty/tools/utils"
 	"os"
 	"path/filepath"
 	"strings"
+	"unicode/utf8"
 )
 
 var _ = fmt.Print
 var path_name_map, remote_dirs map[string]string
 
-var mimetypes_cache, data_cache *utils.LRUCache[string, string]
+var mimetypes_cache, data_cache, hash_cache *utils.LRUCache[string, string]
 var lines_cache *utils.LRUCache[string, []string]
+var is_text_cache *utils.LRUCache[string, bool]
 
 func init_caches() {
-	mimetypes_cache = utils.NewLRUCache[string, string](4096)
-	data_cache = utils.NewLRUCache[string, string](4096)
-	lines_cache = utils.NewLRUCache[string, []string](4096)
+	path_name_map = make(map[string]string, 32)
+	remote_dirs = make(map[string]string, 32)
+	const sz = 4096
+	mimetypes_cache = utils.NewLRUCache[string, string](sz)
+	data_cache = utils.NewLRUCache[string, string](sz)
+	is_text_cache = utils.NewLRUCache[string, bool](sz)
+	lines_cache = utils.NewLRUCache[string, []string](sz)
+	hash_cache = utils.NewLRUCache[string, string](sz)
+}
+
+func add_remote_dir(val string) {
+	x := filepath.Base(val)
+	idx := strings.LastIndex(x, "-")
+	if idx > -1 {
+		x = x[idx+1:]
+	} else {
+		x = ""
+	}
+	remote_dirs[val] = x
 }
 
 func mimetype_for_path(path string) string {
@@ -44,6 +64,38 @@ func data_for_path(path string) (string, error) {
 	})
 }
 
+func is_path_text(path string) bool {
+	return is_text_cache.MustGetOrCreate(path, func(path string) bool {
+		if strings.HasPrefix(mimetype_for_path(path), "image/") {
+			return false
+		}
+		s1, err := os.Stat(path)
+		if err == nil {
+			s2, err := os.Stat("/dev/null")
+			if err == nil && os.SameFile(s1, s2) {
+				return false
+			}
+		}
+		d, err := data_for_path(path)
+		if err != nil {
+			return false
+		}
+		return utf8.ValidString(d)
+	})
+}
+
+func hash_for_path(path string) (string, error) {
+	return hash_cache.GetOrCreate(path, func(path string) (string, error) {
+		ans, err := data_for_path(path)
+		if err != nil {
+			return "", err
+		}
+		hash := md5.Sum(utils.UnsafeStringToBytes(ans))
+		return utils.UnsafeBytesToString(hash[:]), err
+	})
+
+}
+
 func sanitize(x string) string {
 	x = strings.ReplaceAll(x, "\r\n", "⏎\n")
 	return utils.SanitizeControlCodes(x, "░")
@@ -63,12 +115,197 @@ func lines_for_path(path string) ([]string, error) {
 }
 
 type Collection struct {
+	changes, renames, type_map map[string]string
+	adds, removes              *utils.Set[string]
+	all_paths                  []string
+	added_count, removed_count int
+}
+
+func (self *Collection) add_change(left, right string) {
+	self.changes[left] = right
+	self.all_paths = append(self.all_paths, left)
+	self.type_map[left] = `diff`
+}
+
+func (self *Collection) add_rename(left, right string) {
+	self.renames[left] = right
+	self.all_paths = append(self.all_paths, left)
+	self.type_map[left] = `rename`
+}
+
+func (self *Collection) add_add(right string) {
+	self.adds.Add(right)
+	self.all_paths = append(self.all_paths, right)
+	self.type_map[right] = `add`
+	if is_path_text(right) {
+		num, _ := lines_for_path(right)
+		self.added_count += len(num)
+	}
+}
+
+func (self *Collection) add_removal(left string) {
+	self.removes.Add(left)
+	self.all_paths = append(self.all_paths, left)
+	self.type_map[left] = `removal`
+	if is_path_text(left) {
+		num, _ := lines_for_path(left)
+		self.removed_count += len(num)
+	}
+}
+
+func (self *Collection) finalize() {
+	utils.StableSortWithKey(self.all_paths, func(path string) string {
+		return path_name_map[path]
+	})
+}
+
+func (self *Collection) Len() int { return len(self.all_paths) }
+
+func (self *Collection) Items() int { return len(self.all_paths) }
+
+func (self *Collection) Apply(f func(path, typ, data string) error) error {
+	for _, path := range self.all_paths {
+		typ := self.type_map[path]
+		data := ""
+		switch typ {
+		case "diff":
+			data = self.changes[path]
+		case "rename":
+			data = self.renames[path]
+		}
+		if err := f(path, typ, data); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func allowed(path string) bool {
+	name := filepath.Base(path)
+	for _, pat := range conf.Ignore_name {
+		if matched, err := filepath.Match(pat, name); err == nil && matched {
+			return false
+		}
+	}
+	return true
+}
+
+func remote_hostname(path string) (string, string) {
+	for q, val := range remote_dirs {
+		if strings.HasPrefix(path, q) {
+			return q, val
+		}
+	}
+	return "", ""
+}
+
+func resolve_remote_name(path, defval string) string {
+	remote_dir, rh := remote_hostname(path)
+	if remote_dir != "" && rh != "" {
+		r, err := filepath.Rel(remote_dir, path)
+		if err == nil {
+			return rh + ":" + r
+		}
+	}
+	return defval
+}
+
+func walk(base string, names *utils.Set[string], pmap map[string]string) error {
+	return filepath.WalkDir(base, func(path string, d fs.DirEntry, err error) error {
+		is_allowed := allowed(path)
+		if !is_allowed {
+			if d.IsDir() {
+				return fs.SkipDir
+			}
+			return nil
+		}
+		path, err = filepath.Abs(path)
+		if err != nil {
+			return err
+		}
+		name, err := filepath.Rel(base, path)
+		if err != nil {
+			return err
+		}
+		path_name_map[path] = name
+		names.Add(name)
+		pmap[name] = path
+		return nil
+	})
+}
+
+func (self *Collection) collect_files(left, right string) error {
+	left_names, right_names := utils.NewSet[string](16), utils.NewSet[string](16)
+	left_path_map, right_path_map := make(map[string]string, 16), make(map[string]string, 16)
+	err := walk(left, left_names, left_path_map)
+	if err != nil {
+		return err
+	}
+	err = walk(right, right_names, right_path_map)
+	common_names := left_names.Intersect(right_names)
+	changed_names := utils.NewSet[string](common_names.Len())
+	for n := range common_names.Iterable() {
+		ld, err := data_for_path(left_path_map[n])
+		var rd string
+		if err == nil {
+			rd, err = data_for_path(right_path_map[n])
+		}
+		if err != nil {
+			return err
+		}
+		if ld != rd {
+			changed_names.Add(n)
+			self.add_change(left_path_map[n], right_path_map[n])
+		}
+	}
+	removed := left_names.Subtract(common_names)
+	added := right_names.Subtract(common_names)
+	ahash, rhash := make(map[string]string, added.Len()), make(map[string]string, removed.Len())
+	for a := range added.Iterable() {
+		ahash[a], err = hash_for_path(right_path_map[a])
+		if err != nil {
+			return err
+		}
+	}
+	for r := range removed.Iterable() {
+		rhash[r], err = hash_for_path(left_path_map[r])
+		if err != nil {
+			return err
+		}
+	}
+	for name, rh := range rhash {
+		found := false
+		for n, ah := range ahash {
+			if ah == rh {
+				ld, _ := data_for_path(left_path_map[name])
+				rd, _ := data_for_path(right_path_map[n])
+				if ld == rd {
+					self.add_rename(left_path_map[name], right_path_map[n])
+					added.Discard(n)
+					found = true
+					break
+				}
+			}
+		}
+		if !found {
+			self.add_removal(left_path_map[name])
+		}
+	}
+	for name := range added.Iterable() {
+		self.add_add(right_path_map[name])
+	}
+	return nil
 }
 
 func create_collection(left, right string) (ans *Collection, err error) {
-	path_name_map = make(map[string]string, 32)
-	remote_dirs = make(map[string]string, 32)
-	ans = &Collection{}
+	ans = &Collection{
+		changes:   make(map[string]string),
+		renames:   make(map[string]string),
+		type_map:  make(map[string]string),
+		adds:      utils.NewSet[string](32),
+		removes:   utils.NewSet[string](32),
+		all_paths: make([]string, 0, 32),
+	}
 	left_stat, err := os.Stat(left)
 	if err != nil {
 		return nil, err
@@ -89,11 +326,8 @@ func create_collection(left, right string) (ans *Collection, err error) {
 		}
 		path_name_map[pl] = resolve_remote_name(pl, left)
 		path_name_map[pr] = resolve_remote_name(pr, right)
-		err = ans.add_change(pl, pr)
-		if err != nil {
-			return nil, err
-		}
+		ans.add_change(pl, pr)
 	}
-	err = ans.finalize()
+	ans.finalize()
 	return ans, err
 }
diff --git a/tools/cmd/diff/main.go b/tools/cmd/diff/main.go
index 48eb0d6b9..ab4b51587 100644
--- a/tools/cmd/diff/main.go
+++ b/tools/cmd/diff/main.go
@@ -3,12 +3,20 @@
 package diff
 
 import (
+	"archive/tar"
+	"bytes"
 	"fmt"
+	"io/fs"
 	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
 
 	"kitty/tools/cli"
+	"kitty/tools/cmd/ssh"
 	"kitty/tools/config"
 	"kitty/tools/tui/loop"
+	"kitty/tools/utils"
 )
 
 var _ = fmt.Print
@@ -39,6 +47,54 @@ func exists(path string) bool {
 	return err == nil
 }
 
+func get_ssh_file(hostname, rpath string) (string, error) {
+	tdir, err := os.MkdirTemp("", "*-"+hostname)
+	if err != nil {
+		return "", err
+	}
+	add_remote_dir(tdir)
+	is_abs := strings.HasPrefix(rpath, "/")
+	for strings.HasPrefix(rpath, "/") {
+		rpath = rpath[1:]
+	}
+	cmd := []string{ssh.SSHExe(), hostname, "tar", "-c", "-f", "-"}
+	if is_abs {
+		cmd = append(cmd, "-C", "/")
+	}
+	cmd = append(cmd, rpath)
+	c := exec.Command(cmd[0], cmd[1:]...)
+	stdout, err := c.Output()
+	if err != nil {
+		return "", fmt.Errorf("Failed to ssh into remote host %s to get file %s with error: %w", hostname, rpath, err)
+	}
+	tf := tar.NewReader(bytes.NewReader(stdout))
+	count, err := utils.ExtractAllFromTar(tf, tdir)
+	if err != nil {
+		return "", fmt.Errorf("Failed to untar data from remote host %s to get file %s with error: %w", hostname, rpath, err)
+	}
+	ans := filepath.Join(tdir, rpath)
+	if count == 1 {
+		filepath.WalkDir(tdir, func(path string, d fs.DirEntry, err error) error {
+			if !d.IsDir() {
+				ans = path
+				return fs.SkipAll
+			}
+			return nil
+		})
+	}
+	return ans, nil
+}
+
+func get_remote_file(path string) (string, error) {
+	if strings.HasPrefix(path, "ssh:") {
+		parts := strings.SplitN(path, ":", 3)
+		if len(parts) == 3 {
+			return get_ssh_file(parts[1], parts[2])
+		}
+	}
+	return path, nil
+}
+
 func main(_ *cli.Command, opts_ *Options, args []string) (rc int, err error) {
 	opts = opts_
 	conf, err = load_config(opts)
@@ -52,7 +108,19 @@ func main(_ *cli.Command, opts_ *Options, args []string) (rc int, err error) {
 		return 1, err
 	}
 	init_caches()
-	left, right := get_remote_file(args[0]), get_remote_file(args[1])
+	defer func() {
+		for tdir := range remote_dirs {
+			os.RemoveAll(tdir)
+		}
+	}()
+	left, err := get_remote_file(args[0])
+	if err != nil {
+		return 1, err
+	}
+	right, err := get_remote_file(args[1])
+	if err != nil {
+		return 1, err
+	}
 	if isdir(left) != isdir(right) {
 		return 1, fmt.Errorf("The items to be diffed should both be either directories or files. Comparing a directory to a file is not valid.'")
 	}
diff --git a/tools/utils/tar.go b/tools/utils/tar.go
new file mode 100644
index 000000000..1d6ad9963
--- /dev/null
+++ b/tools/utils/tar.go
@@ -0,0 +1,101 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package utils
+
+import (
+	"archive/tar"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var _ = fmt.Print
+
+type TarExtractOptions struct {
+	DontPreservePermissions bool
+}
+
+func ExtractAllFromTar(tr *tar.Reader, dest_path string, optss ...TarExtractOptions) (count int, err error) {
+	opts := TarExtractOptions{}
+	if len(optss) > 0 {
+		opts = optss[0]
+	}
+	dest_path, err = filepath.Abs(dest_path)
+	if err != nil {
+		return
+	}
+
+	mode := func(hdr *tar.Header) fs.FileMode {
+		return fs.FileMode(hdr.Mode) & (fs.ModePerm | fs.ModeSetgid | fs.ModeSetuid | fs.ModeSticky)
+	}
+
+	set_metadata := func(chmod func(mode fs.FileMode) error, hdr *tar.Header) (err error) {
+		if !opts.DontPreservePermissions && chmod != nil {
+			perms := mode(hdr)
+			if err = chmod(perms); err != nil {
+				return err
+			}
+		}
+		count++
+		return
+	}
+
+	for {
+		var hdr *tar.Header
+		hdr, err = tr.Next()
+		if errors.Is(err, io.EOF) {
+			break
+		}
+		if err != nil {
+			return count, err
+		}
+		dest := hdr.Name
+		dest = strings.TrimLeft(dest, "/")
+		if !filepath.IsLocal(dest) {
+			continue
+		}
+		dest = filepath.Join(dest_path, dest)
+		switch hdr.Typeflag {
+		case tar.TypeDir:
+			err = os.MkdirAll(dest, 0o700)
+			if err != nil {
+				return
+			}
+			if err = set_metadata(func(m fs.FileMode) error { return os.Chmod(dest, m) }, hdr); err != nil {
+				return
+			}
+		case tar.TypeReg, tar.TypeRegA:
+			var d *os.File
+			if d, err = os.Create(dest); err != nil {
+				return
+			}
+			err = set_metadata(d.Chmod, hdr)
+			if err == nil {
+				_, err = io.Copy(d, tr)
+			}
+			d.Close()
+			if err != nil {
+				return
+			}
+		case tar.TypeLink:
+			if err = os.Link(hdr.Linkname, dest); err != nil {
+				return
+			}
+			if err = set_metadata(func(m fs.FileMode) error { return os.Chmod(dest, m) }, hdr); err != nil {
+				return
+			}
+		case tar.TypeSymlink:
+			if err = os.Symlink(hdr.Linkname, dest); err != nil {
+				return
+			}
+			if err = set_metadata(nil, hdr); err != nil {
+				return
+			}
+		}
+	}
+	return
+}