Handle multiple Info buffers.

(Info-tag-table-marker): Initialize to nil.
(Info-tag-table-buffer): New variable.
(Info-find-node): Don't switch buffers if already in Info mode.
Use Info-tag-table-buffer to support multiple Info buffers.
(Info-read-subfile): Don't switch to *info* buffer.
(Info-build-node-completions): Handle buffer local bindings for
Info-tag-table-marker.
(Info-search): Add a save-excursion.
(Info-mode): Make Info-tag-table-buffer buffer-local.
Make a different marker in Info-tag-table-marker for each buffer.
(Info-kill-buffer): New function, on kill-buffer-hook.

1 files changed, 87 insertions, 49 deletions

diff --git a/lisp/info.el b/lisp/info.el
index 63076dfa93b..bf25a8522d0 100644
--- a/lisp/info.el
+++ b/lisp/info.el
@@ -114,10 +114,13 @@ or nil if current info file is not split into subfiles.")
 (defvar Info-current-node nil
   "Name of node that Info is now looking at, or nil.")
 
-(defvar Info-tag-table-marker (make-marker)
+(defvar Info-tag-table-marker nil
   "Marker pointing at beginning of current Info file's tag table.
 Marker points nowhere if file has no tag table.")
 
+(defvar Info-tag-table-buffer nil
+  "Buffer used for indirect tag tables.")
+
 (defvar Info-current-file-completions nil
   "Cached completion list for current Info file.")
 
@@ -301,7 +304,7 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
             (cons (list Info-current-file Info-current-node (point))
                   Info-history)))
   ;; Go into info buffer.
-  (pop-to-buffer "*info*")
+  (or (eq major-mode 'Info-mode) (pop-to-buffer "*info*"))
   (buffer-disable-undo (current-buffer))
   (or (eq major-mode 'Info-mode)
       (Info-mode))
@@ -324,12 +327,12 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
                 (setq default-directory (file-name-directory filename)))
               (set-buffer-modified-p nil)
               ;; See whether file has a tag table.  Record the location if yes.
-              (set-marker Info-tag-table-marker nil)
               (goto-char (point-max))
               (forward-line -8)
               ;; Use string-equal, not equal, to ignore text props.
-              (or (string-equal nodename "*")
-                  (not (search-forward "\^_\nEnd tag table\n" nil t))
+              (if (not (or (string-equal nodename "*")
+                           (not
+                            (search-forward "\^_\nEnd tag table\n" nil t))))
                   (let (pos)
                     ;; We have a tag table.  Find its beginning.
                     ;; Is this an indirect file?
@@ -340,16 +343,21 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
                           (looking-at "(Indirect)\n"))
                         ;; It is indirect.  Copy it to another buffer
                         ;; and record that the tag table is in that buffer.
-                        (save-excursion
-                          (let ((buf (current-buffer)))
-                            (set-buffer (get-buffer-create " *info tag table*"))
+                        (let ((buf (current-buffer))
+                              (tagbuf
+                               (or Info-tag-table-buffer
+                                   (generate-new-buffer " *info tag table*"))))
+                          (setq Info-tag-table-buffer tagbuf)
+                          (save-excursion
+                            (set-buffer tagbuf)
                             (buffer-disable-undo (current-buffer))
                             (setq case-fold-search t)
                             (erase-buffer)
-                            (insert-buffer-substring buf)
-                            (set-marker Info-tag-table-marker
-                                        (match-end 0))))
-                      (set-marker Info-tag-table-marker pos))))
+                            (insert-buffer-substring buf))
+                          (set-marker Info-tag-table-marker
+                                      (match-end 0) tagbuf))
+                      (set-marker Info-tag-table-marker pos)))
+                (set-marker Info-tag-table-marker nil))
               (setq Info-current-file
                     (if (eq filename t) "dir" filename))))
         ;; Use string-equal, not equal, to ignore text props.
@@ -364,18 +372,28 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
             ;; read the proper subfile into this buffer.
             (if (marker-position Info-tag-table-marker)
                 (save-excursion
-                  (set-buffer (marker-buffer Info-tag-table-marker))
-                  (goto-char Info-tag-table-marker)
-                  (if (re-search-forward regexp nil t)
-                      (progn
-                        (setq guesspos (read (current-buffer)))
-                        ;; If this is an indirect file,
-                        ;; determine which file really holds this node
-                        ;; and read it in.
-                        (if (not (eq (current-buffer) (get-buffer "*info*")))
-                            (setq guesspos
-                                  (Info-read-subfile guesspos))))
-                    (error "No such node: %s" nodename))))
+                  (let ((m Info-tag-table-marker)
+                        found found-mode)
+                    (save-excursion
+                      (set-buffer (marker-buffer m))
+                      (goto-char m)
+                      (beginning-of-line) ;so re-search will work.
+                      (setq found (re-search-forward regexp nil t))
+                      (if found
+                          (setq guesspos (read (current-buffer))))
+                      (setq found-mode major-mode))
+                    (if found
+                        (progn
+                          ;; If this is an indirect file, determine
+                          ;; which file really holds this node and
+                          ;; read it in.
+                          (if (not (eq found-mode 'Info-mode))
+                              ;; Note that the current buffer must be
+                              ;; the *info* buffer on entry to
+                              ;; Info-read-subfile.  Thus the hackery
+                              ;; above.
+                              (setq guesspos (Info-read-subfile guesspos))))
+                      (error "No such node: %s" nodename)))))
             (goto-char (max (point-min) (- guesspos 1000)))
             ;; Now search from our advised position (or from beg of buffer)
             ;; to find the actual node.
@@ -548,6 +566,8 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
     (setq Info-dir-contents (buffer-string)))
   (setq default-directory Info-dir-contents-directory))
 
+;; Note that on entry to this function the current-buffer must be the
+;; *info* buffer; not the info tags buffer.
 (defun Info-read-subfile (nodepos)
   ;; NODEPOS is either a position (in the Info file as a whole,
   ;; not relative to a subfile) or the name of a subfile.
@@ -577,7 +597,8 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
                 (forward-line 1)))))
       (setq lastfilename nodepos)
       (setq lastfilepos 0))
-    (set-buffer (get-buffer "*info*"))
+    ;; Assume previous buffer is in Info-mode.
+    ;; (set-buffer (get-buffer "*info*"))
     (or (equal Info-current-subfile lastfilename)
         (let ((buffer-read-only nil))
           (setq buffer-file-name nil)
@@ -686,10 +707,10 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
         (save-excursion
           (save-restriction
             (if (marker-buffer Info-tag-table-marker)
-                (progn
-                  (set-buffer (marker-buffer Info-tag-table-marker))
+                (let ((marker Info-tag-table-marker))
+                  (set-buffer (marker-buffer marker))
                   (widen)
-                  (goto-char Info-tag-table-marker)
+                  (goto-char marker)
                   (while (re-search-forward "\nNode: \\(.*\\)\177" nil t)
                     (setq compl
                           (cons (list (buffer-substring (match-beginning 1)
@@ -747,27 +768,28 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
     (if (not found) ;can only happen in subfile case -- else would have erred
         (unwind-protect
             (let ((list ()))
-              (set-buffer (marker-buffer Info-tag-table-marker))
-              (goto-char (point-min))
-              (search-forward "\n\^_\nIndirect:")
-              (save-restriction
-                (narrow-to-region (point)
-                                  (progn (search-forward "\n\^_")
-                                         (1- (point))))
+              (save-excursion
+                (set-buffer (marker-buffer Info-tag-table-marker))
                 (goto-char (point-min))
-                (search-forward (concat "\n" osubfile ": "))
-                (beginning-of-line)
-                (while (not (eobp))
-                  (re-search-forward "\\(^.*\\): [0-9]+$")
-                  (goto-char (+ (match-end 1) 2))
-                  (setq list (cons (cons (read (current-buffer))
-                                         (buffer-substring (match-beginning 1)
-                                                           (match-end 1)))
-                                   list))
-                  (goto-char (1+ (match-end 0))))
-                (setq list (nreverse list)
-                      current (car (car list))
-                      list (cdr list)))
+                (search-forward "\n\^_\nIndirect:")
+                (save-restriction
+                  (narrow-to-region (point)
+                                    (progn (search-forward "\n\^_")
+                                           (1- (point))))
+                  (goto-char (point-min))
+                  (search-forward (concat "\n" osubfile ": "))
+                  (beginning-of-line)
+                  (while (not (eobp))
+                    (re-search-forward "\\(^.*\\): [0-9]+$")
+                    (goto-char (+ (match-end 1) 2))
+                    (setq list (cons (cons (read (current-buffer))
+                                           (buffer-substring
+                                            (match-beginning 1) (match-end 1)))
+                                     list))
+                    (goto-char (1+ (match-end 0))))
+                  (setq list (nreverse list)
+                        current (car (car list))
+                        list (cdr list))))
               (while list
                 (message "Searching subfile %s..." (cdr (car list)))
                 (Info-read-subfile (car (car list)))
@@ -809,7 +831,7 @@ In standalone mode, \\<Info-mode-map>\\[Info-exit] exits Emacs itself."
 
 ;; Return the node name in the buffer following point.
 ;; ALLOWEDCHARS, if non-nil, goes within [...] to make a regexp
-;; saying which chas may appear in the node name.
+;; saying which chars may appear in the node name.
 (defun Info-following-node-name (&optional allowedchars)
   (skip-chars-forward " \t")
   (buffer-substring-no-properties
@@ -1735,6 +1757,9 @@ Advanced commands:
   (make-local-variable 'Info-current-subfile)
   (make-local-variable 'Info-current-node)
   (make-local-variable 'Info-tag-table-marker)
+  (setq Info-tag-table-marker (make-marker))
+  (make-local-variable 'Info-tag-table-buffer)
+  (setq Info-tag-table-buffer nil)
   (make-local-variable 'Info-history)
   (make-local-variable 'Info-index-alternatives)
   (if (memq (framep (selected-frame)) '(x pc w32))
@@ -1874,6 +1899,8 @@ the variable `Info-file-list-for-emacs'."
           ;; Get Info running, and pop to it in another window.
           (save-window-excursion
             (info))
+          ;; FIXME It would be cool if this could use a buffer other
+          ;; than *info*.
           (pop-to-buffer "*info*")
           (Info-find-node (car (car where))
                           (car (cdr (car where))))
@@ -1962,6 +1989,17 @@ The alist key is the character the title is underlined with (?*, ?= or ?-).")
               (put-text-property (match-beginning 1) (match-end 1)
                                  'mouse-face 'highlight))))
       (set-buffer-modified-p nil))))
+
+
+;; When an Info buffer is killed, make sure the associated tags buffer
+;; is killed too.
+(defun Info-kill-buffer ()
+  (and (eq major-mode 'Info-mode)
+       Info-tag-table-buffer
+       (kill-buffer Info-tag-table-buffer)))
+
+(add-hook 'kill-buffer-hook 'Info-kill-buffer)
+  
 
 (provide 'info)