emacs/lisp/eshell/esh-ext.el

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EmacsLisp

;;; esh-ext.el --- commands external to Eshell -*- lexical-binding:t -*-
;; Copyright (C) 1999-2024 Free Software Foundation, Inc.
;; Author: John Wiegley <johnw@gnu.org>
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;; To force a command to invoked external, either provide an explicit
;; pathname for the command argument, or prefix the command name with
;; an asterix character. Example:
;;
;; grep ; make invoke `grep' Lisp function, or `eshell/grep'
;; /bin/grep ; will definitely invoke /bin/grep
;; *grep ; will also invoke /bin/grep
;;; Code:
(eval-when-compile (require 'cl-lib))
(require 'esh-io)
(require 'esh-arg)
(require 'esh-opt)
(require 'esh-proc)
(require 'esh-util)
(defgroup eshell-ext nil
"External commands are invoked when operating system executables are
loaded into memory, thus beginning a new process."
:tag "External commands"
:group 'eshell)
;;; User Variables:
(defcustom eshell-ext-load-hook nil
"A hook that gets run when `eshell-ext' is loaded."
:version "24.1" ; removed eshell-ext-initialize
:type 'hook
:group 'eshell-ext)
(defcustom eshell-binary-suffixes exec-suffixes
"A list of suffixes used when searching for executable files."
:type '(repeat string)
:group 'eshell-ext)
(defcustom eshell-force-execution
(not (null (memq system-type '(windows-nt ms-dos))))
"If non-nil, try to execute files regardless of execute permissions.
This can be useful on systems like Windows, where the operating system
doesn't support the execution bit for shell scripts; or in cases where
you want to associate an interpreter with a particular kind of script
file, but the language won't let you but a `#!' interpreter line in
the file, and you don't want to make it executable since nothing else
but Eshell will be able to understand
`eshell-interpreter-alist'."
:type 'boolean
:group 'eshell-ext)
(defun eshell-search-path (name)
"Search the environment path for NAME."
(if (file-name-absolute-p name)
name
(let ((list (eshell-get-path))
suffixes n1 n2 file)
(while list
(setq n1 (file-name-concat (car list) name))
(setq suffixes eshell-binary-suffixes)
(while suffixes
(setq n2 (concat n1 (car suffixes)))
(if (and (or (file-executable-p n2)
(and eshell-force-execution
(file-readable-p n2)))
(not (file-directory-p n2)))
(setq file n2 suffixes nil list nil))
(setq suffixes (cdr suffixes)))
(setq list (cdr list)))
file)))
(defcustom eshell-windows-shell-file
(if (eshell-under-windows-p)
(if (string-match "\\(cmdproxy\\|sh\\)\\.\\(com\\|exe\\)"
shell-file-name)
(or (eshell-search-path "cmd.exe")
(eshell-search-path "command.com"))
shell-file-name))
"The name of the shell command to use for DOS/Windows batch files.
This defaults to nil on non-Windows systems, where this variable is
wholly ignored."
:type '(choice file (const nil))
:group 'eshell-ext)
(autoload 'eshell-parse-command "esh-cmd")
(defsubst eshell-invoke-batch-file (&rest args)
"Invoke a .BAT or .CMD file on MS-DOS/MS-Windows systems."
;; since CMD.EXE can't handle forward slashes in the initial
;; argument...
(setcar args (subst-char-in-string ?/ ?\\ (car args)))
(throw 'eshell-replace-command
(eshell-parse-command
(eshell-quote-argument eshell-windows-shell-file)
(cons "/c" args))))
(defcustom eshell-interpreter-alist
(if (eshell-under-windows-p)
'(("\\.\\(bat\\|cmd\\)\\'" . eshell-invoke-batch-file)))
"An alist defining interpreter substitutions.
Each member is a cons cell of the form:
(MATCH . INTERPRETER)
MATCH should be a regexp, which is matched against the command
name, or a function of arity 2 receiving the COMMAND and its
ARGS (a list). If either returns a non-nil value, then
INTERPRETER will be used for that command.
If INTERPRETER is a string, it will be called as the command name,
with the original command name passed as the first argument, with all
subsequent arguments following. If INTERPRETER is a function, it will
be called with all of those arguments. Note that interpreter
functions should throw `eshell-replace-command' with the alternate
command form, or they should return a value compatible with the
possible return values of `eshell-external-command', which see."
:type '(repeat (cons (choice regexp (function :tag "Predicate"))
(choice string (function :tag "Interpreter"))))
:group 'eshell-ext)
(defcustom eshell-alternate-command-hook nil
"A hook run whenever external command lookup fails.
If a functions wishes to provide an alternate command, they must throw
it using the tag `eshell-replace-command'. This is done because the
substituted command need not be external at all, and therefore must be
passed up to a higher level for re-evaluation.
Or, if the function returns a filename, that filename will be invoked
with the current command arguments rather than the command specified
by the user on the command line."
:type 'hook
:group 'eshell-ext)
(defcustom eshell-command-interpreter-max-length 256
"The maximum length of any command interpreter string, plus args."
:type 'integer
:group 'eshell-ext)
(defcustom eshell-explicit-command-char ?*
"If this char occurs before a command name, call it externally.
That is, although `vi' may be an alias, `*vi' will always call the
external version."
:type 'character
:group 'eshell-ext)
(defcustom eshell-explicit-remote-commands t
"If non-nil, support explicitly-remote commands.
These are commands with a full remote file name, such as
\"/ssh:host:whoami\". If this is enabled, you can also explicitly run
commands on your local host by using the \"/local:\" prefix, like
\"/local:whoami\"."
:type 'boolean
:group 'eshell-ext)
;;; Functions:
(defconst eshell--local-prefix "/local:")
(defun eshell-ext-initialize () ;Called from `eshell-mode' via intern-soft!
"Initialize the external command handling code."
(add-hook 'eshell-named-command-hook #'eshell-quoted-file-command nil t)
(add-hook 'eshell-named-command-hook #'eshell-explicit-command nil t))
(defun eshell-explicit-command--which (command)
(when (and (> (length command) 1)
(eq (aref command 0) eshell-explicit-command-char))
(eshell-external-command--which (substring command 1))))
(defun eshell-explicit-command (command args)
"If a command name begins with \"*\", always call it externally.
This bypasses all Lisp functions and aliases."
(when (and (> (length command) 1)
(eq (aref command 0) eshell-explicit-command-char))
(let ((cmd (eshell-search-path (substring command 1))))
(if cmd
(or (eshell-external-command cmd args)
(error "%s: external command failed" cmd))
(error "%s: external command not found"
(substring command 1))))))
(put 'eshell-explicit-command 'eshell-which-function
#'eshell-explicit-command--which)
(defun eshell-quoted-file-command--which (command)
(when (file-name-quoted-p command)
(eshell-external-command--which (file-name-unquote command))))
(defun eshell-quoted-file-command (command args)
"If a command name begins with \"/:\", always call it externally.
Similar to `eshell-explicit-command', this bypasses all Lisp functions
and aliases, but it also ignores file name handlers."
(when (file-name-quoted-p command)
(eshell-external-command (file-name-unquote command) args)))
(put 'eshell-quoted-file-command 'eshell-which-function
#'eshell-quoted-file-command--which)
(defun eshell-remote-command (command args)
"Insert output from a remote COMMAND, using ARGS.
A \"remote\" command in Eshell is something that executes on a different
machine. If COMMAND is a remote file name, run it on the host for that
file; if COMMAND is a local file name, run it locally."
(let* ((cwd-connection (file-remote-p default-directory))
(command-connection (file-remote-p command))
(default-directory (if (equal cwd-connection command-connection)
default-directory
(or command-connection (expand-file-name "~"))))
;; Never use the remote connection here. We don't want to
;; expand the local name! Instead, we want it as the user
;; typed, so that if COMMAND is "/ssh:host:cat", we just get
;; "cat" as the result.
(command-localname (or (file-remote-p command 'localname 'never)
command)))
(eshell-connection-local-command command-localname args)))
(defun eshell-connection-local-command (command args)
"Insert output from an external COMMAND, using ARGS.
This always runs COMMAND using the connection associated with the
current working directory."
(setq args (eshell-stringify-list (flatten-tree args)))
(let ((interp (eshell-find-interpreter
command
args
;; `eshell-find-interpreter' does not work correctly
;; for Tramp file name syntax. But we don't need to
;; know the interpreter in that case, therefore the
;; check is suppressed.
(or (and (stringp command) (file-remote-p command))
(file-remote-p default-directory)))))
(cl-assert interp)
(if (functionp (car interp))
(apply (car interp) (append (cdr interp) args))
(eshell-gather-process-output
(car interp) (append (cdr interp) args)))))
(defun eshell-external-command--which (command)
(or (eshell-search-path command)
(error "no %s in (%s)" command
(string-join (eshell-get-path t) (path-separator)))))
(defun eshell-external-command (command args)
"Insert output from an external COMMAND, using ARGS."
(cond
((and eshell-explicit-remote-commands
(file-remote-p command))
(eshell-remote-command command args))
((and eshell-explicit-remote-commands
(string-prefix-p eshell--local-prefix command))
(eshell-remote-command
(substring command (length eshell--local-prefix)) args))
(t
(eshell-connection-local-command command args))))
(defun eshell/addpath (&rest args)
"Add a set of paths to PATH."
(eshell-eval-using-options
"addpath" args
'((?b "begin" nil prepend "add to beginning of $PATH")
(?h "help" nil nil "display this usage message")
:usage "[-b] DIR...
Adds the given DIR to $PATH.")
(let ((path (eshell-get-path t)))
(if args
(progn
(setq path (if prepend
(append args path)
(append path args)))
(eshell-set-path path)
(string-join path (path-separator)))
(dolist (dir path)
(eshell-printn dir))))))
(put 'eshell/addpath 'eshell-no-numeric-conversions t)
(put 'eshell/addpath 'eshell-filename-arguments t)
(defun eshell-script-interpreter (file)
"Extract the script to run from FILE, if it has #!<interp> in it.
Return nil, or a list of the form:
(INTERPRETER [ARGS] FILE)"
(let ((maxlen eshell-command-interpreter-max-length))
(if (and (file-readable-p file)
(file-regular-p file)
;; If the file is zero bytes, it can't possibly have a
;; shebang. This check may seem redundant, but we can
;; encounter files that Emacs considers both readable and
;; regular, but which aren't *actually* readable. This can
;; happen, for example, with certain kinds of reparse
;; points like APPEXECLINK on NTFS filesystems (MS-Windows
;; uses these for "app execution aliases"). In these
;; cases, the file size is 0, so this check protects us
;; from errors.
(> (file-attribute-size (file-attributes file)) 0))
(with-temp-buffer
(insert-file-contents-literally file nil 0 maxlen)
(if (looking-at "#![ \t]*\\([^ \r\t\n]+\\)\\([ \t]+\\(.+\\)\\)?")
(if (match-string 3)
(list (match-string 1)
(match-string 3)
file)
(list (match-string 1)
file)))))))
(defun eshell-find-interpreter (file args &optional no-examine-p)
"Find the command interpreter with which to execute FILE.
If NO-EXAMINE-P is non-nil, FILE will not be inspected for a script
line of the form #!<interp>."
(let ((finterp
(catch 'found
(ignore
(dolist (possible eshell-interpreter-alist)
(cond
((functionp (car possible))
(let ((fn (car possible)))
(and (funcall fn file args)
(throw 'found (cdr possible)))))
((stringp (car possible))
(and (string-match (car possible) file)
(throw 'found (cdr possible))))
(t
(error "Invalid interpreter-alist test"))))))))
(if finterp ; first check
(list finterp file)
(let ((fullname (if (file-name-directory file) file
(eshell-search-path file)))
(suffixes eshell-binary-suffixes))
(when (and fullname
(not (file-remote-p fullname))
(file-remote-p default-directory))
(setq fullname
(if (file-name-absolute-p fullname)
(concat (file-remote-p default-directory) fullname)
(expand-file-name fullname default-directory))))
(if (and fullname (not (or eshell-force-execution
(file-executable-p fullname))))
(while suffixes
(let ((try (concat fullname (car suffixes))))
(if (or (file-executable-p try)
(and eshell-force-execution
(file-readable-p try)))
(setq fullname try suffixes nil)
(setq suffixes (cdr suffixes))))))
(cond ((not (and fullname (file-exists-p fullname)))
(let ((name (or fullname file)))
(unless (setq fullname
(run-hook-with-args-until-success
'eshell-alternate-command-hook file))
(error "%s: command not found" name))))
((not (or eshell-force-execution
(file-executable-p fullname)))
(error "%s: Permission denied" fullname)))
(let (interp)
(unless no-examine-p
(setq interp (eshell-script-interpreter fullname))
(if interp
(setq interp
(cons (car (eshell-find-interpreter (car interp) args t))
(cdr interp)))))
(or interp (list fullname)))))))
(provide 'esh-ext)
;;; esh-ext.el ends here