Add a new, faster procedure for loading this package

3 files changed, 88 insertions, 3 deletions

diff --git a/NEWS b/NEWS
index ed91464..2f4218e 100644
--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,10 @@
    pdf-annot-default-markup-annotation-properties.  The new variable
    let's the user choose default properties, e.g. a color, for all
    supported annotations separately.
+** Provide a faster "boot-loader"
+   The autoloaded function `pdf-loader-install' acts as a replacement
+   for ‘pdf-tools-install’ and makes Emacs load and use PDF Tools as soon
+   as a PDF file is opened, but not sooner.
 * Version 0.80
 ** Tablist package
    The files tablist.el and tablist-filter.el are no longer part of
diff --git a/README.org b/README.org
index 5158bf5..34791f7 100644
--- a/README.org
+++ b/README.org
@@ -277,9 +277,14 @@
 #+begin_src elisp
   (pdf-tools-install)
 #+end_src
-  somewhere in your ~.emacs~. Next you probably want to take a look at
-  the various features of what you've just installed.  The following
-  two commands might be of help for doing so.
+  somewhere in your ~.emacs~.  Alternatively, and if you care about
+  start-up time, you may want to use 
+#+begin_src elisp
+  (pdf-loader-install)
+#+end_src
+  instead.  Next you probably want to take a look at the various
+  features of what you've just installed.  The following two commands
+  might be of help for doing so.
 #+begin_src elisp
   M-x pdf-tools-help RET
   M-x pdf-tools-customize RET
diff --git a/lisp/pdf-loader.el b/lisp/pdf-loader.el
new file mode 100644
index 0000000..e303755
--- /dev/null
+++ b/lisp/pdf-loader.el
@@ -0,0 +1,76 @@
+;;; pdf-loader.el --- Minimal PDF Tools loader       -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2017  Andreas Politz
+
+;; Author: Andreas Politz <politza@hochschule-trier.de>
+;; Keywords:
+
+;; This program 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.
+
+;; This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;
+
+;;; Code:
+
+(defconst pdf-loader--auto-mode-alist-item
+  (copy-sequence "\\.[pP][dD][fF]\\'")
+  "The item used in `auto-mode-alist'.")
+
+(defconst pdf-loader--magic-mode-alist-item
+  (copy-sequence "%PDF")
+  "The item used in`magic-mode-alist'.")
+
+
+;;;###autoload
+(defun pdf-loader-install (&optional no-query-p skip-dependencies-p
+                                     no-error-p force-dependencies-p)
+  "Prepare Emacs for using PDF Tools.
+
+This function acts as a replacement for `pdf-tools-install' and
+makes Emacs load and use PDF Tools as soon as a PDF file is
+opened, but not sooner.
+
+The arguments are passed verbatim to `pdf-tools-install', which
+see."
+  (let ((args (list no-query-p skip-dependencies-p
+                    no-error-p force-dependencies-p)))
+    (if (featurep 'pdf-tools)
+        (apply #'pdf-tools-install args)
+      (pdf-loader--install
+       (apply #'pdf-loader-load args)))))
+
+(defun pdf-loader--load (&rest args)
+  (pdf-loader--uninstall)
+  (save-selected-window
+    (pdf-tools-install args)))
+
+(defun pdf-loader--install (loader)
+  (setf (alist-get pdf-loader--auto-mode-alist-item
+                   auto-mode-alist nil nil #'equal)
+        loader)
+  (setf (alist-get pdf-loader--magic-mode-alist-item
+                   magic-mode-alist nil nil #'equal)
+        loader))
+
+(defun pdf-loader--uninstall ()
+  (setf (alist-get pdf-loader--auto-mode-alist-item
+                   auto-mode-alist nil :remove #'equal)
+        nil)
+  (setf (alist-get pdf-loader--magic-mode-alist-item
+                   magic-mode-alist nil :remove #'equal)
+        nil))
+
+(provide 'pdf-loader)
+;;; pdf-loader.el ends here