More work on porting diff kitten

tools/cmd/diff/collect.go

@@ -0,0 +1,48 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package diff
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+var _ = fmt.Print
+var path_name_map, remote_dirs map[string]string
+
+type Collection struct {
+}
+
+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{}
+	left_stat, err := os.Stat(left)
+	if err != nil {
+		return nil, err
+	}
+	if left_stat.IsDir() {
+		err = ans.collect_files(left, right)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		pl, err := filepath.Abs(left)
+		if err != nil {
+			return nil, err
+		}
+		pr, err := filepath.Abs(right)
+		if err != nil {
+			return nil, err
+		}
+		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
+		}
+	}
+	err = ans.finalize()
+	return ans, err
+}

tools/cmd/diff/main.go

@@ -4,6 +4,7 @@ package diff
 
 import (
 	"fmt"
+	"os"
 
 	"kitty/tools/cli"
 	"kitty/tools/config"
@@ -26,6 +27,18 @@ var conf *Config
 var opts *Options
 var lp *loop.Loop
 
+func isdir(path string) bool {
+	if s, err := os.Stat(path); err == nil {
+		return s.IsDir()
+	}
+	return false
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path)
+	return err == nil
+}
+
 func main(_ *cli.Command, opts_ *Options, args []string) (rc int, err error) {
 	opts = opts_
 	conf, err = load_config(opts)
@@ -35,7 +48,19 @@ func main(_ *cli.Command, opts_ *Options, args []string) (rc int, err error) {
 	if len(args) != 2 {
 		return 1, fmt.Errorf("You must specify exactly two files/directories to compare")
 	}
-	left, right := args[0], args[1]
+	if err = set_diff_command(conf.Diff_cmd); err != nil {
+		return 1, err
+	}
+	left, right := get_remote_file(args[0]), get_remote_file(args[1])
+	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.'")
+	}
+	if !exists(left) {
+		return 1, fmt.Errorf("%s does not exist", left)
+	}
+	if !exists(right) {
+		return 1, fmt.Errorf("%s does not exist", right)
+	}
 	lp, err = loop.New()
 	if err != nil {
 		return 1, err

tools/cmd/diff/patch.go

@@ -0,0 +1,84 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package diff
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"kitty/tools/utils"
+	"kitty/tools/utils/shlex"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+var _ = fmt.Print
+
+const GIT_DIFF = `git diff --no-color --no-ext-diff --exit-code -U_CONTEXT_ --no-index --`
+const DIFF_DIFF = `diff -p -U _CONTEXT_ --`
+
+var diff_cmd []string
+
+var GitExe = (&utils.Once[string]{Run: func() string {
+	return utils.FindExe("git")
+}}).Get
+
+var DiffExe = (&utils.Once[string]{Run: func() string {
+	return utils.FindExe("diff")
+}}).Get
+
+func find_differ() error {
+	if GitExe() != "git" && exec.Command(GitExe(), "--help").Run() == nil {
+		diff_cmd, _ = shlex.Split(GIT_DIFF)
+		return nil
+	}
+	if DiffExe() != "diff" && exec.Command(DiffExe(), "--help").Run() == nil {
+		diff_cmd, _ = shlex.Split(DIFF_DIFF)
+		return nil
+	}
+	return fmt.Errorf("Neither the git nor the diff programs were found in PATH")
+}
+
+func set_diff_command(q string) error {
+	if q == "auto" {
+		return find_differ()
+	}
+	c, err := shlex.Split(q)
+	if err == nil {
+		diff_cmd = c
+	}
+	return err
+}
+
+func run_diff(file1, file2 string, num_of_context_lines int) (ok, is_different bool, patch string, err error) {
+	context := strconv.Itoa(num_of_context_lines)
+	cmd := utils.Map(func(x string) string {
+		return strings.ReplaceAll(x, "_CONTEXT_", context)
+	}, diff_cmd)
+	// we resolve symlinks because git diff does not follow symlinks, while diff
+	// does. We want consistent behavior, also for integration with git difftool
+	// we always want symlinks to be followed.
+	path1, err := filepath.EvalSymlinks(file1)
+	if err != nil {
+		return
+	}
+	path2, err := filepath.EvalSymlinks(file2)
+	if err != nil {
+		return
+	}
+	cmd = append(cmd, path1, path2)
+	c := exec.Command(cmd[0], cmd[1:]...)
+	stdout, stderr := bytes.Buffer{}, bytes.Buffer{}
+	c.Stdout, c.Stderr = &stdout, &stderr
+	err = c.Run()
+	if err != nil {
+		var e *exec.ExitError
+		if errors.As(err, &e) && e.ExitCode() == 1 {
+			return true, true, stdout.String(), nil
+		}
+		return false, false, stderr.String(), err
+	}
+	return true, false, stdout.String(), nil
+}

tools/cmd/hyperlinked_grep/main.go

@@ -23,15 +23,7 @@ import (
 var _ = fmt.Print
 
 var RgExe = (&utils.Once[string]{Run: func() string {
-	ans := utils.Which("rg")
-	if ans != "" {
-		return ans
-	}
-	ans = utils.Which("rg", utils.DefaultExeSearchPaths()...)
-	if ans == "" {
-		ans = "rg"
-	}
-	return ans
+	return utils.FindExe("rg")
 }}).Get
 
 func get_options_for_rg() (expecting_args map[string]bool, alias_map map[string]string, err error) {

tools/cmd/ssh/utils.go

@@ -18,15 +18,7 @@ import (
 var _ = fmt.Print
 
 var SSHExe = (&utils.Once[string]{Run: func() string {
-	ans := utils.Which("ssh")
-	if ans != "" {
-		return ans
-	}
-	ans = utils.Which("ssh", utils.DefaultExeSearchPaths()...)
-	if ans == "" {
-		ans = "ssh"
-	}
-	return ans
+	return utils.FindExe("ssh")
 }}).Get
 
 var SSHOptions = (&utils.Once[map[string]string]{Run: func() (ssh_options map[string]string) {

tools/utils/which.go

@@ -47,3 +47,15 @@ func Which(cmd string, paths ...string) string {
 	}
 	return ""
 }
+
+func FindExe(name string) string {
+	ans := Which(name)
+	if ans != "" {
+		return ans
+	}
+	ans = Which(name, DefaultExeSearchPaths()...)
+	if ans == "" {
+		ans = name
+	}
+	return ans
+}