Implement connection-local variables

* doc/lispref/variables.texi (Connection Local Variables): New section.

* etc/NEWS: Mention connection-local variables.

* lisp/files-x.el (enable-connection-local-variables)
(connection-local-variables-alist, connection-local-class-alist)
(connection-local-criteria-alist): New defvars.
(connection-local-get-classes)
(connection-local-get-class-variables): New defsubst.
(connection-local-set-classes)
(connection-local-set-class-variables)
(hack-connection-local-variables)
(hack-connection-local-variables-apply): New defuns.
(with-connection-local-classes): New defmacro.

* lisp/net/tramp.el (tramp-set-connection-local-variables): New defun.

* lisp/net/tramp-adb.el (tramp-adb-maybe-open-connection):
* lisp/net/tramp-gvfs.el (tramp-gvfs-maybe-open-connection):
* lisp/net/lisp/net/tramp-sh.el (tramp-maybe-open-connection):
* lisp/net/tramp-smb.el (tramp-smb-maybe-open-connection): Use it.

* test/lisp/files-x-tests.el: New file.

1 files changed, 297 insertions, 0 deletions

diff --git a/test/lisp/files-x-tests.el b/test/lisp/files-x-tests.el
new file mode 100644
index 00000000000..8f2c11d391c
--- /dev/null
+++ b/test/lisp/files-x-tests.el
@@ -0,0 +1,297 @@
+;;; files-x-tests.el --- tests for files-x.el.
+
+;; Copyright (C) 2016 Free Software Foundation, Inc.
+
+;; Author: Michael Albinus <michael.albinus@gmx.de>
+
+;; 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 <http://www.gnu.org/licenses/>.
+
+;;; Code:
+
+(require 'ert)
+(require 'files-x)
+
+(defvar files-x-test--criteria1 "my-user@my-remote-host")
+(defvar files-x-test--criteria2
+  (lambda (identification)
+    (string-match "another-user@my-remote-host" identification)))
+(defvar files-x-test--criteria3 nil)
+
+(defvar files-x-test--variables1
+  '((remote-shell-file-name . "/bin/bash")
+    (remote-shell-command-switch . "-c")
+    (remote-shell-interactive-switch . "-i")
+    (remote-shell-login-switch . "-l")))
+(defvar files-x-test--variables2
+  '((remote-shell-file-name . "/bin/ksh")))
+(defvar files-x-test--variables3
+  '((remote-null-device . "/dev/null")))
+(defvar files-x-test--variables4
+  '((remote-null-device . "null")))
+
+(ert-deftest files-x-test-connection-local-set-class-variables ()
+  "Test setting connection-local class variables."
+
+  ;; Declare (CLASS VARIABLES) objects.
+  (let (connection-local-class-alist connection-local-criteria-alist)
+    (connection-local-set-class-variables 'remote-bash files-x-test--variables1)
+    (should
+     (equal
+      (connection-local-get-class-variables 'remote-bash)
+      files-x-test--variables1))
+
+    (connection-local-set-class-variables 'remote-ksh files-x-test--variables2)
+    (should
+     (equal
+      (connection-local-get-class-variables 'remote-ksh)
+      files-x-test--variables2))
+
+    (connection-local-set-class-variables
+     'remote-nullfile files-x-test--variables3)
+    (should
+     (equal
+      (connection-local-get-class-variables 'remote-nullfile)
+      files-x-test--variables3))
+
+    ;; A redefinition overwrites existing values.
+    (connection-local-set-class-variables
+     'remote-nullfile files-x-test--variables4)
+    (should
+     (equal
+      (connection-local-get-class-variables 'remote-nullfile)
+      files-x-test--variables4))))
+
+(ert-deftest files-x-test-connection-local-set-classes ()
+  "Test setting connection-local classes."
+
+  ;; Declare (CRITERIA CLASSES) objects.
+  (let (connection-local-class-alist connection-local-criteria-alist)
+    (connection-local-set-class-variables 'remote-bash files-x-test--variables1)
+    (connection-local-set-class-variables 'remote-ksh files-x-test--variables2)
+    (connection-local-set-class-variables
+     'remote-nullfile files-x-test--variables3)
+
+    (connection-local-set-classes
+     files-x-test--criteria1 'remote-bash 'remote-ksh)
+    (should
+     (equal
+      (connection-local-get-classes files-x-test--criteria1)
+      '(remote-bash remote-ksh)))
+
+    (connection-local-set-classes files-x-test--criteria2 'remote-ksh)
+    (should
+     (equal
+      (connection-local-get-classes files-x-test--criteria2)
+      '(remote-ksh)))
+    ;; A further call adds classes.
+    (connection-local-set-classes files-x-test--criteria2 'remote-nullfile)
+    (should
+     (equal
+      (connection-local-get-classes files-x-test--criteria2)
+      '(remote-ksh remote-nullfile)))
+    ;; Adding existing classes doesn't matter.
+    (connection-local-set-classes
+     files-x-test--criteria2 'remote-bash 'remote-nullfile)
+    (should
+     (equal
+      (connection-local-get-classes files-x-test--criteria2)
+      '(remote-ksh remote-nullfile remote-bash)))
+
+    ;; An empty variable list is accepted (but makes no sense).
+    (connection-local-set-classes files-x-test--criteria3)
+    (should-not (connection-local-get-classes files-x-test--criteria3))
+
+    ;; Using a nil criteria also works.  Duplicate classes are trashed.
+    (connection-local-set-classes
+     files-x-test--criteria3 'remote-bash 'remote-ksh 'remote-ksh 'remote-bash)
+    (should
+     (equal
+      (connection-local-get-classes files-x-test--criteria3)
+      '(remote-bash remote-ksh)))
+
+    ;; A criteria other than nil, regexp or lambda function is wrong.
+    (should-error (connection-local-set-classes 'dummy))))
+
+(ert-deftest files-x-test-hack-connection-local-variables-apply ()
+  "Test setting connection-local variables."
+
+  (let (connection-local-class-alist connection-local-criteria-alist)
+
+    (connection-local-set-class-variables 'remote-bash files-x-test--variables1)
+    (connection-local-set-class-variables 'remote-ksh files-x-test--variables2)
+    (connection-local-set-class-variables
+     'remote-nullfile files-x-test--variables3)
+
+    (connection-local-set-classes
+     files-x-test--criteria1 'remote-bash 'remote-ksh)
+    (connection-local-set-classes
+     files-x-test--criteria2 'remote-ksh 'remote-nullfile)
+
+    ;; Apply the variables.
+    (with-temp-buffer
+      (let ((enable-connection-local-variables t)
+            (default-directory "/sudo:my-user@my-remote-host:"))
+        (should-not connection-local-variables-alist)
+        (should-not (local-variable-p 'remote-shell-file-name))
+        (should-not (boundp 'remote-shell-file-name))
+        (hack-connection-local-variables-apply)
+        ;; All connection-local variables are set.  They apply in
+        ;; reverse order in `connection-local-variables-alist'.  The
+        ;; settings from `remote-ksh' are not contained, because they
+        ;; declare same variables as in `remote-bash'.
+        (should
+         (equal connection-local-variables-alist
+                (nreverse (copy-tree files-x-test--variables1))))
+        ;; The variables exist also as local variables.
+        (should (local-variable-p 'remote-shell-file-name))
+        ;; The proper variable value is set.
+        (should
+         (string-equal (symbol-value 'remote-shell-file-name) "/bin/bash"))))
+
+    ;; The second test case.
+    (with-temp-buffer
+      (let ((enable-connection-local-variables t)
+            (default-directory "/ssh:another-user@my-remote-host:"))
+        (should-not connection-local-variables-alist)
+        (should-not (local-variable-p 'remote-shell-file-name))
+        (should-not (boundp 'remote-shell-file-name))
+        (hack-connection-local-variables-apply)
+        ;; All connection-local variables are set.  They apply in
+        ;; reverse order in `connection-local-variables-alist'.
+        (should
+         (equal connection-local-variables-alist
+                (append
+                 (nreverse (copy-tree files-x-test--variables3))
+                 (nreverse (copy-tree files-x-test--variables2)))))
+        ;; The variables exist also as local variables.
+        (should (local-variable-p 'remote-shell-file-name))
+        ;; The proper variable value is set.
+        (should
+         (string-equal (symbol-value 'remote-shell-file-name) "/bin/ksh"))))
+
+    ;; The third test case.  Both `files-x-test--criteria1' and
+    ;; `files-x-test--criteria3' apply, but there are no double
+    ;; entries.
+    (connection-local-set-classes
+     files-x-test--criteria3 'remote-bash 'remote-ksh)
+    (with-temp-buffer
+      (let ((enable-connection-local-variables t)
+            (default-directory "/sudo:my-user@my-remote-host:"))
+        (should-not connection-local-variables-alist)
+        (should-not (local-variable-p 'remote-shell-file-name))
+        (should-not (boundp 'remote-shell-file-name))
+        (hack-connection-local-variables-apply)
+        ;; All connection-local variables are set.  They apply in
+        ;; reverse order in `connection-local-variables-alist'.  The
+        ;; settings from `remote-ksh' are not contained, because they
+        ;; declare same variables as in `remote-bash'.
+        (should
+         (equal connection-local-variables-alist
+                (nreverse (copy-tree files-x-test--variables1))))
+        ;; The variables exist also as local variables.
+        (should (local-variable-p 'remote-shell-file-name))
+        ;; The proper variable value is set.
+        (should
+         (string-equal (symbol-value 'remote-shell-file-name) "/bin/bash"))))
+
+    ;; When `enable-connection-local-variables' is nil, nothing happens.
+    (with-temp-buffer
+      (let ((enable-connection-local-variables nil)
+            (default-directory "/ssh:another-user@my-remote-host:"))
+        (should-not connection-local-variables-alist)
+        (should-not (local-variable-p 'remote-shell-file-name))
+        (should-not (boundp 'remote-shell-file-name))
+        (hack-connection-local-variables-apply)
+        (should-not connection-local-variables-alist)
+        (should-not (local-variable-p 'remote-shell-file-name))
+        (should-not (boundp 'remote-shell-file-name))))))
+
+(ert-deftest files-x-test-with-connection-local-classes ()
+  "Test setting connection-local variables."
+
+  (let (connection-local-class-alist connection-local-criteria-alist)
+    (connection-local-set-class-variables 'remote-bash files-x-test--variables1)
+    (connection-local-set-class-variables 'remote-ksh files-x-test--variables2)
+    (connection-local-set-class-variables
+     'remote-nullfile files-x-test--variables3)
+    (connection-local-set-classes
+     files-x-test--criteria3 'remote-ksh 'remote-nullfile)
+
+    (with-temp-buffer
+      (let ((enable-connection-local-variables t)
+            (default-directory "/sudo:my-user@my-remote-host:"))
+        (hack-connection-local-variables-apply)
+
+	;; All connection-local variables are set.  They apply in
+        ;; reverse order in `connection-local-variables-alist'.
+        (should
+         (equal connection-local-variables-alist
+		(append
+		 (nreverse (copy-tree files-x-test--variables3))
+		 (nreverse (copy-tree files-x-test--variables2)))))
+        ;; The variables exist also as local variables.
+        (should (local-variable-p 'remote-shell-file-name))
+        (should (local-variable-p 'remote-null-device))
+        ;; The proper variable values are set.
+        (should
+         (string-equal (symbol-value 'remote-shell-file-name) "/bin/ksh"))
+        (should
+         (string-equal (symbol-value 'remote-null-device) "/dev/null"))
+
+	;; A candidate connection-local variable is not bound yet.
+        (should-not (local-variable-p 'remote-shell-command-switch))
+
+	;; Use the macro.
+        (with-connection-local-classes '(remote-bash remote-ksh)
+          ;; All connection-local variables are set.  They apply in
+          ;; reverse order in `connection-local-variables-alist'.
+          ;; This variable keeps only the variables to be set inside
+          ;; the macro.
+          (should
+           (equal connection-local-variables-alist
+                  (nreverse (copy-tree files-x-test--variables1))))
+          ;; The variables exist also as local variables.
+          (should (local-variable-p 'remote-shell-file-name))
+          (should (local-variable-p 'remote-shell-command-switch))
+          ;; The proper variable values are set.  The settings from
+          ;; `remote-bash' overwrite the same variables as in
+          ;; `remote-ksh'.
+          (should
+           (string-equal (symbol-value 'remote-shell-file-name) "/bin/bash"))
+          (should
+           (string-equal (symbol-value 'remote-shell-command-switch) "-c")))
+
+        ;; Everything is rewound.  The old variable values are reset.
+        (should
+         (equal connection-local-variables-alist
+		(append
+		 (nreverse (copy-tree files-x-test--variables3))
+		 (nreverse (copy-tree files-x-test--variables2)))))
+        ;; The variables exist also as local variables.
+        (should (local-variable-p 'remote-shell-file-name))
+        (should (local-variable-p 'remote-null-device))
+        ;; The proper variable values are set.  The settings from
+	;; `remote-ksh' are back.
+        (should
+         (string-equal (symbol-value 'remote-shell-file-name) "/bin/ksh"))
+        (should
+         (string-equal (symbol-value 'remote-null-device) "/dev/null"))
+
+	;; The variable set temporarily is not unbound, again.
+        (should-not (local-variable-p 'remote-shell-command-switch))))))
+
+(provide 'files-x-tests)
+;;; files-x-tests.el ends here