branch: externals/truename-cache
commit 494313c89ac6cdf241412a7445123f9c70c4cf5c
Author: Martin Edström <[email protected]>
Commit: Martin Edström <[email protected]>
Initial commit
---
LICENSE.txt | 674 +++++++++++++++++++++++++++++++++++++++++++++++++++
README.org | 46 ++++
truename-cache.el | 702 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 1422 insertions(+)
diff --git a/LICENSE.txt b/LICENSE.txt
new file mode 100644
index 0000000000..f288702d2f
--- /dev/null
+++ b/LICENSE.txt
@@ -0,0 +1,674 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 3, 29 June 2007
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+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+ 17. Interpretation of Sections 15 and 16.
+
+ If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ 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 <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ <program> Copyright (C) <year> <name of author>
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.
diff --git a/README.org b/README.org
new file mode 100644
index 0000000000..a31557e787
--- /dev/null
+++ b/README.org
@@ -0,0 +1,46 @@
+* truename-cache
+
+This Emacs library provides two things:
+
+1. =truename-cache-get=: A caching alternative to =file-truename=.
+
+2. =truename-cache-collect-files-and-attributes=: Basically an alternative to
=directory-files-recursively= that pre-populates cache and returns truenames
while minimizing calls to =file-truename=.
+
+** Why?
+
+Truenames are useful as a way to de-duplicate file lists and to
cross-reference names in one list with names in another list.
+
+But if you write code that just wraps every file name it encounters in
=(file-truename FILE)=, it gets slow if you have large lists of file names. It
takes 1,000 milliseconds to process 1,000 file names on my machine.
+
+That is unacceptably slow, at least in the use-case where you often scan a
list of directories to see if any new files have appeared or any files were
modified or deleted.
+
+That's the sort of thing that might be done as part of a user command. As we
all know, the rule of thumb for an once-off command to feel "instant" is 100ms
maximum. (Some say 20ms, but that's for code triggered on every keystroke
while typing -- i.e. in Emacs parlance, hooks run by =self-insert-command=).
+
+Another way to de-dup is to refer to filesystem inodes i.e.
=(file-attribute-file-identifier (file-attributes FILE))=, but that is not as
human-friendly to work with as truenames.
+
+** Bonus: Merging lists
+
+The routine =truename-cache-collect-files-and-attributes= can merge multiple
file lists and still return de-duplicated truenames, and tries to do this as
efficiently as possible.
+
+Some example file-lists in Emacs that may have a great deal of overlap between
them:
+
+- Variable =recentf-list=
+- Variable =org-agenda-text-search-extra-files=
+- Variable =org-id-files=
+- Variable =org-id-extra-files=
+- Output of =(org-files-list)=
+- Output of =(hash-table-values org-id-locations)=
+
+This is done through the argument =:infer-dirs-from=. In truth, it doesn't
operate directly on any file names, it just infers their parent directories and
then scans each directory once. That turns out to be efficient, even if it's
likely to pull in more file names than were in the input.
+
+** Bonus: Filtering
+
+While you could simply let =truename-cache-collect-files-and-attributes=
return a giant file list and filter it afterwards, there are two reasons to do
some filtering through the arguments =:rel-file-deny=, =:rel-dir-deny= and/or
=:full-dir-deny=.
+
+1. It filters early, so it can avoid recursing into directories that you were
never gonna keep anyway -- e.g. the contents of =.git/= or =node_modules/=...
+
+ It can easily be the difference between a runtime of 2.00 seconds and 0.02
seconds!
+
+2. If you wanted to apply your filters to relative file names rather than
absolute names, you'd ordinarily have to use =(relative-file-name FILE DIR)= on
every file, and that procedure isn't cheap either.
+
+ That's why it provides =:rel-file-deny=, =:rel-dir-deny=. Another
bottleneck dodged.
diff --git a/truename-cache.el b/truename-cache.el
new file mode 100644
index 0000000000..617bb3eceb
--- /dev/null
+++ b/truename-cache.el
@@ -0,0 +1,702 @@
+;;; truename-cache.el --- Efficiently de-dup files by truename -*-
lexical-binding: t; -*-
+
+;; Copyright (C) 2026 Martin Edström
+;;
+;; 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/>.
+
+;; Author: Martin Edström <[email protected]>
+;; URL: https://github.com/meedstrom/truename-cache
+;; Created: 2026-02-16
+;; Keywords: lisp
+;; Package-Requires: ((emacs "26.1") (compat "30.1"))
+
+;;; Commentary:
+
+;; This library provides two things:
+
+;; 1. A caching alternative to `file-truename'.
+
+;; See docstring of `truename-cache-get'.
+
+;; 2. An alternative to `directory-files-recursively' that pre-populates said
+;; cache and returns truenames while minimizing calls to `file-truename'.
+
+;; See docstring of `truename-cache-collect-files-and-attributes'.
+
+;;; Code:
+
+(require 'cl-lib)
+(require 'map)
+(require 'seq)
+(require 'compat)
+
+;;;; Name-cache:
+
+(defvar truename-cache--wild<>true (make-hash-table :test 'equal))
+(defvar truename-cache--true<>wilds (make-hash-table :test 'equal))
+(defvar truename-cache--true<>dir-abbr (make-hash-table :test 'equal))
+(defvar truename-cache--true<>full-abbr (make-hash-table :test 'equal))
+
+(defun truename-cache--populate (wild-files truename)
+ "Taking TRUENAME as the truename of WILD-FILES, add them to the cache.
+Return TRUENAME.
+Input WILD-FILES may be either a list, nil, or a single string.
+
+Even if WILD-FILES is nil, this caches the abbreviations of TRUENAME as
+well as TRUENAME itself, as wild file names it is possible to encounter.
+
+Warning: Make sure to have called `truename-cache--init-abbreviator'.
+See docstring `truename-cache--fast-full-abbrev'."
+ (let* ((case-fold-search (file-name-case-insensitive-p truename))
+ (dir-abbr-true (directory-abbrev-apply truename))
+ (full-abbr-true (truename-cache--fast-full-abbrev truename)))
+ (puthash truename truename truename-cache--wild<>true)
+ (puthash dir-abbr-true truename truename-cache--wild<>true)
+ (puthash full-abbr-true truename truename-cache--wild<>true)
+ (puthash truename dir-abbr-true truename-cache--true<>dir-abbr)
+ (puthash truename full-abbr-true truename-cache--true<>full-abbr)
+ ;; Add to a mirror-table for efficient `truename-cache-invalidate'.
+ (push truename (gethash truename truename-cache--true<>wilds))
+ (push dir-abbr-true (gethash truename truename-cache--true<>wilds))
+ (push full-abbr-true (gethash truename truename-cache--true<>wilds))
+ ;; Add `wild-files' as additional wild names.
+ (dolist (wild-file (ensure-list wild-files))
+ (puthash wild-file truename truename-cache--wild<>true)
+ (push wild-file (gethash truename truename-cache--true<>wilds))))
+ truename)
+
+(defun truename-cache-invalidate (bad-name)
+ "Invalidate BAD-NAME in the name cache, allowing to cache fresh values.
+Return the list of variant file names invalidated, including BAD-NAME."
+ (let ((all-bad)
+ (true (gethash bad-name truename-cache--wild<>true)))
+ (when true
+ (push true all-bad)
+ (dolist (wild (gethash true truename-cache--true<>wilds))
+ (push wild all-bad)))
+ ;; Example situation: File WILD is a symlink that changed destination.
+ ;; So cached TRUE led to a nonexistent file last time it was accessed,
+ ;; whereupon hopefully, something arranged to have this function called
+ ;; with TRUE as argument, bringing us here.
+ ;; Now invalidate WILD so we can cache a correct TRUE next time.
+ (dolist (wild (gethash bad-name truename-cache--true<>wilds))
+ (unless (member wild all-bad)
+ (push wild all-bad)))
+ (dolist (bad-variant all-bad)
+ (remhash bad-variant truename-cache--wild<>true)
+ (remhash bad-variant truename-cache--true<>wilds)
+ (remhash bad-variant truename-cache--true<>dir-abbr)
+ (remhash bad-variant truename-cache--true<>full-abbr))
+ all-bad))
+
+(defun truename-cache-reset ()
+ "Wipe the name cache."
+ (clrhash truename-cache--wild<>true)
+ (clrhash truename-cache--true<>wilds)
+ (clrhash truename-cache--true<>dir-abbr)
+ (clrhash truename-cache--true<>full-abbr))
+
+
+;;;; Name-cache getters:
+
+(defun truename-cache-get (wild)
+ "Try to return the true name for file name WILD.
+The first time this function sees WILD, it uses the expensive
+`file-truename', but then it caches that result for future calls.
+
+The cache can be cleaned by:
+- `truename-cache-invalidate'
+- `truename-cache-reset'
+
+See alternatives:
+- `truename-cache-get'
+- `truename-cache-get-cached-p'
+- `truename-cache-get-existed-p'
+- `truename-cache-get-exists-p'
+- `truename-cache-get-dir-abbrev'
+- `truename-cache-get-dir-abbrev-cached-p'
+- `truename-cache-get-dir-abbrev-existed-p'
+- `truename-cache-get-dir-abbrev-exists-p'
+- `truename-cache-get-full-abbrev'
+- `truename-cache-get-full-abbrev-cached-p'
+- `truename-cache-get-full-abbrev-existed-p'
+- `truename-cache-get-full-abbrev-exists-p'"
+ (unless (file-name-absolute-p wild)
+ (setq wild (expand-file-name wild)))
+ (or (gethash wild truename-cache--wild<>true)
+ (truename-cache--populate wild (file-truename wild))))
+
+(defun truename-cache-get-cached-p (wild)
+ "Try to return the true name for file name WILD, or nil.
+
+Like `truename-cache-get', but on a cache miss, return nil."
+ (unless (file-name-absolute-p wild)
+ (setq wild (expand-file-name wild)))
+ (gethash wild truename-cache--wild<>true))
+
+(defun truename-cache-get-existed-p (wild)
+ "Try to return the true name for file name WILD, or nil.
+
+Like `truename-cache-get', but on a cache miss, pass WILD to
+`file-truename' only if WILD exists now, then cache and return the
+new truename only if it exists, else return nil."
+ (unless (file-name-absolute-p wild)
+ (setq wild (expand-file-name wild)))
+ (or (gethash wild truename-cache--wild<>true)
+ (and (file-exists-p wild)
+ (let ((true (file-truename wild)))
+ (when (file-exists-p true)
+ (truename-cache--populate wild true))))))
+
+(defun truename-cache-get-exists-p (wild)
+ "Try to return the true name for file name WILD, or nil.
+
+Like `truename-cache-get', but verify that the cached truename exists on
+disk now, else re-cache it like `truename-cache-get-existed-p'.
+
+This can be meaningfully slower than `truename-cache-get-existed-p' on a
+slow filesystem, in theory, but it should still be much faster than
+`file-truename' once most names are cached."
+ (unless (file-name-absolute-p wild)
+ (setq wild (expand-file-name wild)))
+ (let ((true (gethash wild truename-cache--wild<>true)))
+ (or (and true
+ (if (file-exists-p true)
+ true
+ (truename-cache-invalidate true)
+ nil))
+ (when (file-exists-p wild)
+ (setq true (file-truename wild))
+ (when (file-exists-p true)
+ (truename-cache--populate wild true))))))
+
+
+;;;; Name-cache getters with dir abbrev:
+
+(defun truename-cache-get-dir-abbrev (wild)
+ "Probable truename of WILD with `directory-abbrev-apply' applied.
+Behave like `truename-cache-get'."
+ (gethash (truename-cache-get wild) truename-cache--true<>dir-abbr))
+
+(defun truename-cache-get-dir-abbrev-cached-p (wild)
+ "Probable truename of WILD with `directory-abbrev-apply' applied, or nil.
+Behave like `truename-cache-get-cached-p'."
+ (gethash (truename-cache-get-cached-p wild) truename-cache--true<>dir-abbr))
+
+(defun truename-cache-get-dir-abbrev-existed-p (wild)
+ "Probable truename of WILD with `directory-abbrev-apply' applied, or nil.
+Behave like `truename-cache-get-existed-p'."
+ (gethash (truename-cache-get-existed-p wild) truename-cache--true<>dir-abbr))
+
+(defun truename-cache-get-dir-abbrev-exists-p (wild)
+ "Probable truename of WILD with `directory-abbrev-apply' applied, or nil.
+Behave like `truename-cache-get-exists-p'."
+ (gethash (truename-cache-get-exists-p wild) truename-cache--true<>dir-abbr))
+
+
+;;;; Name-cache getters with full abbrev:
+
+(defun truename-cache-get-full-abbrev (wild)
+ "Probable truename of WILD with `abbreviate-file-name' applied.
+Behave like `truename-cache-get'."
+ (gethash (truename-cache-get wild) truename-cache--true<>full-abbr))
+
+(defun truename-cache-get-full-abbrev-cached-p (wild)
+ "Probable truename of WILD with `abbreviate-file-name' applied, or nil.
+Behave like `truename-cache-get-cached-p'."
+ (gethash (truename-cache-get-cached-p wild) truename-cache--true<>full-abbr))
+
+(defun truename-cache-get-full-abbrev-existed-p (wild)
+ "Probable truename of WILD with `abbreviate-file-name' applied, or nil.
+Behave like `truename-cache-get-existed-p'."
+ (gethash (truename-cache-get-existed-p wild)
truename-cache--true<>full-abbr))
+
+(defun truename-cache-get-full-abbrev-exists-p (wild)
+ "Probable truename of WILD with `abbreviate-file-name' applied, or nil.
+Behave like `truename-cache-get-exists-p'."
+ (gethash (truename-cache-get-exists-p wild) truename-cache--true<>full-abbr))
+
+
+;;;; Ersatz `abbreviate-file-name':
+
+;; By using `truename-cache--init-abbreviator' to override
+;; `truename-cache--home-re' to new regexp before use (even if it is
+;; already set), this allows `truename-cache--fast-full-abbrev' to avoid
+;; making `expand-file-name' calls every time as `abbreviate-file-name' does.
+(defvar truename-cache--home-re nil)
+(defun truename-cache--init-abbreviator ()
+ "Set some variables needed by `truename-cache--fast-full-abbrev'."
+ (let ((home (expand-file-name "~")))
+ (when (and truename-cache--home-re
+ (not (string-match-p truename-cache--home-re home)))
+ (lwarn 'truename-cache :warning
+ "Meaning of ~ has changed to \"%s\", does not match regexp \"%s\""
+ home truename-cache--home-re))
+ (setq truename-cache--home-re (directory-abbrev-make-regexp home))))
+
+(truename-cache--init-abbreviator) ;; Set an initial value at load time
+
+;; Justification: It is true that `abbreviate-file-name' performs just fine in
+;; most cases. 110ms for 3k filenames on my machine.
+;; But:
+;; - That's a ~2019 fullblown laptop.
+;; - That's a local filesystem, network can be much worse.
+;; - The point of optimizing `truename-cache-collect-files-and-attributes' is
+;; so you can invoke it as part of user commands, as e.g. a check for
+;; whether any files have changed.
+;; - User commands should run in less than 100ms to feel instant
+;; (some say 20ms but that's for code tied to `self-insert-command'),
+;; and that benchmark has already blown the budget,
+;; for "only" 3k filenames, in ideal conditions.
+;; Now consider 30k filenames in non-ideal conditions.
+;; Keep in mind, that using `abbreviate-file-name' can make it responsible
+;; for the majority of `truename-cache-collect-files-and-attributes' runtime.
+(defun truename-cache--fast-full-abbrev (file)
+ "Abbreviate FILE, faster than `abbreviate-file-name'.
+Can be even faster by let-binding `file-name-handler-alist' to nil.
+
+Warning:
+When not called by `truename-cache-collect-files-and-attributes':
+1. You must let-bind `case-fold-search' around this function.
+ See docstring `directory-abbrev-apply'.
+2. You must call `truename-cache--init-abbreviator' first,
+ ideally in the same buffer to avoid effect from buffer-local envvars."
+ (if-let* ((handler (find-file-name-handler file 'abbreviate-file-name)))
+ (funcall handler 'abbreviate-file-name file)
+ (setq file (directory-abbrev-apply file))
+ (if (and (string-match truename-cache--home-re file)
+ (not (and (= (match-end 0) 1)
+ (= (aref file 0) ?/)))
+ (not (and (memq system-type '(ms-dos windows-nt cygwin))
+ (string-match-p "\\`[a-zA-`]:/\\'" file))))
+ (concat "~" (substring file (match-beginning 1)))
+ file)))
+
+
+;;;; The great machine:
+
+(defun truename-cache--join-regexps (list-of-regexps)
+ "Turn LIST-OF-REGEXPS into a single regexp."
+ (mapconcat (lambda (regexp)
+ (concat "\\(?:" regexp "\\)"))
+ list-of-regexps
+ "\\|"))
+
+(defun truename-cache--mk-handler-alist (&rest subsets)
+ (let ((subset (cl-loop for subset in subsets
+ if (eq t subset)
+ return t
+ else append subset)))
+ (if (eq t subset)
+ file-name-handler-alist
+ (setq subset (delete-dups subset))
+ (cl-loop for (regexp . handler) in file-name-handler-alist
+ when (member handler subset)
+ collect (cons regexp handler)))))
+
+(defun truename-cache--mutate-args (args)
+ "Mutate plist ARGS in place, setting defaults and adding some keys."
+ (cl-assert (not (null args))) ; So it's safe to use `plist-put' without
`setq'
+ (unless (memq :return-files args) (plist-put args :return-files t))
+ (unless (memq :keep-remotes args) (plist-put args :keep-remotes t))
+ (unless (memq :side-effect args) (plist-put args :side-effect t))
+ (unless (memq :assert-readable args) (plist-put args :assert-readable t))
+ (unless (memq :local-name-handlers args) (plist-put args
:local-name-handlers t))
+ (unless (memq :remote-name-handlers args) (plist-put args
:remote-name-handlers t))
+ (map-let (:return-files :return-dirs :dirs-recursive :dirs-flat) args
+ (unless (or return-files return-dirs)
+ (error "Must have at least one of: RETURN-FILES, RETURN-DIRS"))
+ (unless (or dirs-flat dirs-recursive (memq :infer-dirs-from args))
+ (error "Must have at least one of: DIRS-FLAT, DIRS-RECURSIVE,
INFER-DIRS-FROM")))
+ (map-let (:full-dir-deny :relative-dir-deny :relative-file-deny) args
+ (when relative-dir-deny
+ (plist-put args :REL-DIR-DENY-RE
+ (truename-cache--join-regexps relative-dir-deny)))
+ (when relative-file-deny
+ (plist-put args :REL-FILE-DENY-RE
+ (truename-cache--join-regexps relative-file-deny)))
+ (when full-dir-deny
+ (plist-put args :FULL-DIR-DENY-RE
+ (truename-cache--join-regexps full-dir-deny))))
+ (map-let (:local-name-handlers :remote-name-handlers) args
+ (plist-put args :LOCAL-HANDLER-ALIST (truename-cache--mk-handler-alist
+ local-name-handlers))
+ (plist-put args :REMOTE-HANDLER-ALIST (truename-cache--mk-handler-alist
+ remote-name-handlers))
+ (plist-put args :MERGED-HANDLER-ALIST (truename-cache--mk-handler-alist
+ local-name-handlers
remote-name-handlers))))
+
+(defvar truename-cache--dedupped-dirs (make-hash-table :test 'equal))
+(defvar truename-cache--dedupped-results (make-hash-table :test 'equal))
+(defvar truename-cache--visited (make-hash-table :test 'equal))
+
+(cl-defun truename-cache-collect-files-and-attributes
+ ( &rest args &key
+ _side-effect
+ dirs-flat
+ dirs-recursive
+ infer-dirs-from
+ _relative-file-deny
+ _relative-dir-deny
+ _full-dir-deny
+ _return-files
+ _return-dirs
+ _resolve-symlinks
+ _dirs-recursive-follow-symlinks
+ _keep-remotes
+ _local-name-handlers
+ _remote-name-handlers
+ abbrev
+ _assert-readable)
+ "Return an unsorted alist \((FILE1 . ATTR1) (FILE2 . ATTR2) ...\).
+
+
+This is engineered to be as fast as possible at collecting a file list
+from a variety of information sources \(such from as both `org-id-files'
+and `org-directory'\), de-duplicated and in truename form.
+
+The file attribute lists ATTR1, ATTR2... \(per `file-attributes'\) are
+included in case they are needed, because that is faster than querying
+the filesystem later on for the attributes of one file at a time.
+
+When SIDE-EFFECT \(default t\), this function also pre-populates a cache
+used by another tool `truename-cache-get', so that the tool need not be
+expensive even the first time a given file is passed to it.
+
+This function does not itself look up cache.
+
+
+ARGS are a plist of keyword arguments.
+All arguments default to nil unless otherwise specified.
+
+The list of candidates to return comes from scanning a set of
+directories specified by any or all of the following arguments,
+of which at least one must be non-nil:
+
+- DIRS-FLAT :: List of directories to scan.
+- DIRS-RECURSIVE :: List of directories to scan recursively.
+- INFER-DIRS-FROM :: List of file names which are then used to infer
+ directories to scan, as if they had been passed to DIRS-FLAT.
+ The file names must be absolute, else they are ignored.
+
+ It is fine and normal to pass many duplicates.
+
+ Unlike DIRS-FLAT, any inferred directory that happens to be a
+ descendant of DIRS-RECURSIVE is dropped, on the assumption that
+ DIRS-RECURSIVE will get to it anyway.
+ If you want to include a descendant that otherwise fails a filter
+ \(i.e. runs afoul of RELATIVE-DIR-DENY or RESOLVE-SYMLINKS while
+ recursing\), pass it in DIRS-FLAT.
+
+Most other arguments have the effect of narrowing down the candidates.
+
+First, the following filters are applied to the part of a file
+name that is relative to one of aforementioned set of directories.
+
+\(To clarify: if the file was found in DIRS-RECURSIVE, the relative name
+can contain multiple directory components, otherwise it is simply the
+`file-name-nondirectory' of the file.\)
+
+- RELATIVE-FILE-DENY :: List of regexps that reject a file or directory.
+
+ When in doubt, prefer RELATIVE-DIR-DENY, see below.
+ This mostly exists to support existing user options in various
+ packages that are designed to operate on file names instead of
+ directory names.
+ If the purpose is only to filter names found inside a given set of
+ directories, and not at all to prevent potential millions of
+ recursions, you may as well just filter the final result.
+
+- RELATIVE-DIR-DENY :: List of regexps that reject a directory.
+
+ Only relevant with DIRS-RECURSIVE.
+ Applied to directory names \(with trailing slash\) to decide whether
+ or not to recurse into it.
+
+ Important performance knob! If this function is ever slow, the
+ bottleneck is certainly from recursing too many times, if not your
+ network connection.
+ To check which directories were accessed, eval:
+ \(hash-table-keys truename-cache--visited\)
+
+Other filters:
+
+- FULL-DIR-DENY :: Like RELATIVE-DIR-DENY but can be relevant even if
+ DIRS-RECURSIVE is nil, and are applied to absolute names instead of
+ relative names.
+
+ In addition to the usual purpose of preventing recursion, they are
+ applied to DIRS-FLAT, DIRS-RECURSIVE and the directories inferred
+ via INFER-DIRS-FROM.
+ At that time, they are applied to both the possibly non-true input
+ name and the true name.
+ At all other times, they are only applied to true names.
+
+The following arguments affect what kinds of files to include in the
+result. They also affect which symlink destinations to include.
+
+- RETURN-FILES :: Include non-directory files. \(default t\)
+- RETURN-DIRS :: Include directories.
+- RESOLVE-SYMLINKS :: Include symlink destinations resolved into true
+ names, if they exist and satisfy RETURN-FILES or RETURN-DIRS.
+ If nil, symlinks are excluded entirely.
+
+There is no way to include symlinks and not resolve them, and no way to
+include inaccessible symlink destinations, because it cannot be verified
+that they are true names.
+
+DIRS-RECURSIVE-FOLLOW-SYMLINKS says to traverse symlinks found via
+DIRS-RECURSIVE to other directories, recursively. Infinite recursion
+cannot happen.
+Only relevant if RESOLVE-SYMLINKS is also t.
+
+KEEP-REMOTES \(default t\) says to allow looking in directories that are
+remote, i.e. that satisfy `file-remote-p'.
+
+The following two performance knobs can be t, nil or a list of symbols
+like the cdrs of `file-name-handler-alist'. They specify which file
+name handlers to allow, and t means allow all of them:
+
+- LOCAL-NAME-HANDLERS \(default t\) :: Applied in directories that
+ dissatisfy `file-remote-p'. This can often be set to nil with no
+ ill effect.
+- REMOTE-NAME-HANDLERS \(default t\) :: Applied in directories that
+ satisfy `file-remote-p'.
+ Mostly used if KEEP-REMOTES is t, but may also affect the
+ determination of whether a directory or a symlink destination is
+ remote in the first place, so only set it to nil if you are
+ confident there will be no remote names.
+
+ABBREV transforms each file name returned.
+It can take one of three values:
+
+- nil :: Return true names that work with `get-truename-buffer'.
+- `dir' :: Return names more likely to match instances of
+ variable `buffer-file-name' and to work with `get-file-buffer'.
+ See `truename-cache-get-dir-abbrev'.
+- `full' :: Return names that can be expected to match instances of
+ variable `buffer-file-truename'.
+ See `truename-cache-get-full-abbrev'.
+
+ This match is reliable except when the value of LOCAL-NAME-HANDLERS
+ or REMOTE-NAME-HANDLERS causes an abbreviation handler to not be
+ used. In most cases, you probably can assume it is reliable anyway.
+
+ASSERT-READABLE \(default t\) says to signal an error when encountering
+unreadable directories and invalid symlinks.
+Otherwise, they are quietly skipped."
+ (truename-cache--mutate-args args)
+ (map-let ( :assert-readable :side-effect
+ :MERGED-HANDLER-ALIST :FULL-DIR-DENY-RE) args
+ (let* ((current-time-list nil)
+ (file-name-handler-alist MERGED-HANDLER-ALIST)
+ ;; NOTE: It's tempting to dedup with `string-prefix-p' so as to
+ ;; only recurse from the ultimate roots, but user must be allowed to
+ ;; pass specific subdirs that would otherwise be blocked by a
+ ;; deny-regexp or by :resolve-symlinks nil.
+ (filtered-true-recursive-roots
+ (delete-dups
+ (cl-loop
+ for dir in (delete-dups dirs-recursive)
+ when (and (or (file-name-absolute-p dir)
+ (error "Non-absolute name in DIRS-RECURSIVE: %s"
dir))
+ (or (not FULL-DIR-DENY-RE)
+ (not (string-match-p FULL-DIR-DENY-RE dir))))
+ as true-dir = (file-name-as-directory (file-truename dir))
+ when (and (or (file-readable-p true-dir)
+ (when assert-readable
+ (error "Directory not readable: %s" dir)))
+ (or (not FULL-DIR-DENY-RE)
+ (not (string-match-p FULL-DIR-DENY-RE true-dir))))
+ collect true-dir)))
+ (test-roots (delete-dups (append filtered-true-recursive-roots
+ dirs-recursive)))
+ (inferred-dirs
+ (progn
+ ;; We expect a LOT of dups here, it's typical.
+ ;; So use a dedicated table for dedupping.
+ (clrhash truename-cache--dedupped-dirs)
+ (let (file-name-handler-alist) ;; HACK: speed up
`file-name-directory'
+ (dolist (name infer-dirs-from)
+ (when (file-name-absolute-p name)
+ (puthash (if (directory-name-p name) name
(file-name-directory name))
+ t
+ truename-cache--dedupped-dirs))))
+ (cl-loop
+ for dir being each hash-key of truename-cache--dedupped-dirs
+ ;; Try to minimize redundant `file-truename' calls later,
+ ;; which easily consume a majority of CPU time.
+ unless (cl-some (lambda (root) (string-prefix-p root dir))
+ test-roots)
+ collect dir)))
+ (all-flat-dirs
+ (progn
+ (dolist (dir dirs-flat)
+ (unless (file-name-absolute-p name)
+ (error "Non-absolute name in DIRS-FLAT: %s" dir)))
+ (delete-dups
+ (cl-loop
+ for dir in (delete-dups (append dirs-flat inferred-dirs))
+ as true-dir = (file-name-as-directory (file-truename dir))
+ when (and (or (file-readable-p true-dir)
+ (if assert-readable
+ (error "Directory not readable: %s" dir)
+ nil))
+ (or (not FULL-DIR-DENY-RE)
+ (not (string-match-p FULL-DIR-DENY-RE
true-dir))))
+ collect true-dir)))))
+ (clrhash truename-cache--visited)
+ (clrhash truename-cache--dedupped-results)
+ (with-temp-buffer ; No buffer-env
+ (truename-cache--init-abbreviator)
+ ;; NOTE: Do the recursive analyses first, lest a flat dir
+ ;; added to `truename-cache--visited' block a later recursion.
+ (dolist (dir filtered-true-recursive-roots)
+ (truename-cache--analyze-recursively dir args))
+ (dolist (dir all-flat-dirs)
+ (truename-cache--analyze dir args)))
+ (let ((final-alist (map-into truename-cache--dedupped-results 'list)))
+ (when abbrev
+ (cl-assert (or (eq abbrev 'full) (eq abbrev 'dir)))
+ (when (not side-effect)
+ (error "Argument ABBREV non-nil depends on SIDE-EFFECT t"))
+ (if (eq abbrev 'dir)
+ (cl-loop
+ for cell in final-alist
+ do (setcar cell (gethash (car cell)
+ truename-cache--true<>dir-abbr)))
+ (cl-loop
+ for cell in final-alist
+ do (setcar cell (gethash (car cell)
+ truename-cache--true<>full-abbr)))))
+ final-alist))))
+
+(defun truename-cache--analyze-recursively (true-dir args)
+ "Analyze TRUE-DIR recursively.
+ARGS mostly as in `truename-cache-collect-files-and-attributes'."
+ (truename-cache--analyze true-dir (append '(:RECURSE t) args)))
+
+(defun truename-cache--analyze (true-dir args)
+ "Analyze TRUE-DIR, maybe recursively.
+ARGS mostly as in `truename-cache-collect-files-and-attributes'."
+ (map-let (:keep-remotes :REMOTE-HANDLER-ALIST :LOCAL-HANDLER-ALIST) args
+ (let ((default-directory (file-name-as-directory true-dir)))
+ (if (file-remote-p true-dir)
+ (when keep-remotes
+ (let ((file-name-handler-alist REMOTE-HANDLER-ALIST))
+ (truename-cache--analyze-1 "" args true-dir)))
+ (let ((file-name-handler-alist LOCAL-HANDLER-ALIST))
+ (truename-cache--analyze-1 "" args true-dir))))))
+
+(defun truename-cache--analyze-1 (rel-dir args true-dir)
+ "Subroutine of `truename-cache--analyze'.
+Analyze REL-DIR, a relative name to `default-directory'.
+
+ARGS mostly as in `truename-cache-collect-files-and-attributes'.
+
+TRUE-DIR is the true name of REL-DIR, such that when concatenated
+\(using `file-name-concat'\) with the non-directory name of any
+non-symlink file in REL-DIR, becomes the true name of that file."
+ (map-let ( :side-effect :return-dirs :return-files :resolve-symlinks
+ :dirs-recursive-follow-symlinks :keep-remotes :assert-readable
+ :RECURSE :REL-FILE-DENY-RE :REL-DIR-DENY-RE :FULL-DIR-DENY-RE
+ :MERGED-HANDLER-ALIST :LOCAL-HANDLER-ALIST :REMOTE-HANDLER-ALIST)
+ args
+ (cl-loop
+ with case-fold-fs = (file-name-case-insensitive-p true-dir)
+ for (bare-name . attr)
+ in (if assert-readable
+ (directory-files-and-attributes rel-dir nil nil t 'integer)
+ (ignore-error permission-denied
+ (directory-files-and-attributes rel-dir nil nil t 'integer)))
+ as rel-name = (file-name-concat rel-dir bare-name)
+ as true-name = (file-name-concat true-dir bare-name)
+ when (and bare-name
+ (not (member bare-name '("." "..")))
+ (not (and REL-FILE-DENY-RE
+ (string-match-p REL-FILE-DENY-RE rel-name))))
+ when (cond
+ ((null (file-attribute-type attr))
+ return-files)
+
+ ((eq t (file-attribute-type attr))
+ (when (and RECURSE
+ (not (gethash true-name truename-cache--visited))
+ (or (not REL-DIR-DENY-RE)
+ (not (string-match-p REL-DIR-DENY-RE
+ (file-name-as-directory
rel-name))))
+ (or (not FULL-DIR-DENY-RE)
+ (not (string-match-p FULL-DIR-DENY-RE
+ (file-name-as-directory
true-name)))))
+ (puthash true-name t truename-cache--visited)
+ (truename-cache--analyze-1 rel-name args true-name))
+ return-dirs)
+
+ ((stringp (file-attribute-type attr))
+ (let ((file-name-handler-alist MERGED-HANDLER-ALIST)
+ resolved resolved-is-dir resolved-is-remote)
+ (when (and resolve-symlinks
+ ;; Technically though unconventional, this could
+ ;; already be considered a true name; the true name
+ ;; of the symlink. Now we need the true name of
+ ;; the symlink target, so get that.
+ (setq resolved (file-truename true-name))
+ (prog1 t
+ (setq resolved-is-remote (file-remote-p resolved))
+ (if resolved-is-remote
+ (setq file-name-handler-alist
REMOTE-HANDLER-ALIST)
+ (setq file-name-handler-alist
LOCAL-HANDLER-ALIST)))
+ (or (not resolved-is-remote)
+ keep-remotes)
+ (setq attr (if assert-readable
+ (file-attributes resolved)
+ (ignore-error permission-denied
+ (file-attributes resolved))))
+ (or (and return-files
+ (null (file-attribute-type attr)))
+ (and (eq t (file-attribute-type attr))
+ (setq resolved-is-dir t)
+ return-dirs)))
+ (puthash resolved attr truename-cache--dedupped-results)
+ (when side-effect
+ (let ((case-fold-search (file-name-case-insensitive-p
resolved)))
+ (truename-cache--populate true-name resolved))))
+
+ (when (and resolved-is-dir
+ RECURSE
+ dirs-recursive-follow-symlinks
+ (not (gethash resolved truename-cache--visited))
+ (or (not REL-DIR-DENY-RE)
+ (not (string-match-p REL-DIR-DENY-RE
+ (file-name-as-directory
rel-name))))
+ (or (not FULL-DIR-DENY-RE)
+ (not (string-match-p FULL-DIR-DENY-RE
+ (file-name-as-directory
resolved)))))
+ (if resolved-is-remote
+ (when keep-remotes
+ (puthash resolved t truename-cache--visited)
+ (truename-cache--analyze-1 rel-name args resolved))
+ (puthash resolved t truename-cache--visited)
+ (truename-cache--analyze-1 rel-name args resolved))))
+ nil))
+
+ do
+ (puthash true-name attr truename-cache--dedupped-results)
+ (when side-effect
+ (let ((case-fold-search case-fold-fs))
+ (truename-cache--populate nil true-name))))))
+
+(provide 'truename-cache)
+
+;;; truename-cache.el ends here
