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+;;; Lisparuga
+;;; Copyright © 2020 David Thompson <dthompson2@worcester.edu>
+;;;
+;;; Lisparuga 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.
+;;;
+;;; Lisparuga 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 Lisparuga. If not, see <http://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;;
+;; Inotify bindings.
+;;
+;;; Code:
+
+(define-module (lisparuga inotify)
+ #:use-module (ice-9 binary-ports)
+ #:use-module (ice-9 format)
+ #:use-module (ice-9 match)
+ #:use-module (rnrs bytevectors)
+ #:use-module (srfi srfi-9)
+ #:use-module (srfi srfi-9 gnu)
+ #:use-module (system foreign)
+ #:export (make-inotify
+ inotify?
+ inotify-watches
+ inotify-add-watch!
+ inotify-pending-events?
+ inotify-read-event
+ inotify-watch?
+ inotify-watch-id
+ inotify-watch-file-name
+ inotify-watch-remove!
+ inotify-event?
+ inotify-event-watch
+ inotify-event-type
+ inotify-event-cookie
+ inotify-event-file-name))
+
+(define libc (dynamic-link))
+
+(define inotify-init
+ (pointer->procedure int (dynamic-func "inotify_init" libc) '()))
+
+(define inotify-add-watch
+ (pointer->procedure int (dynamic-func "inotify_add_watch" libc)
+ (list int '* uint32)))
+
+(define inotify-rm-watch
+ (pointer->procedure int (dynamic-func "inotify_rm_watch" libc)
+ (list int int)))
+
+(define IN_ACCESS #x00000001) ; file was accessed.
+(define IN_MODIFY #x00000002) ; file was modified.
+(define IN_ATTRIB #x00000004) ; metadata changed
+(define IN_CLOSE_WRITE #x00000008) ; file opened for writing closed
+(define IN_CLOSE_NOWRITE #x00000010) ; file not opened for writing closed
+(define IN_OPEN #x00000020) ; file was opened
+(define IN_MOVED_FROM #x00000040) ; file was moved from X
+(define IN_MOVED_TO #x00000080) ; file was moved to Y
+(define IN_CREATE #x00000100) ; subfile was created
+(define IN_DELETE #x00000200) ; subfile was deleted
+(define IN_DELETE_SELF #x00000400) ; self was deleted
+(define IN_MOVE_SELF #x00000800) ; self was moved
+;; Kernel flags
+(define IN_UNMOUNT #x00002000) ; backing fs was unmounted
+(define IN_Q_OVERFLOW #x00004000) ; event queue overflowed
+(define IN_IGNORED #x00008000) ; file was ignored
+;; Special flags
+(define IN_ONLYDIR #x01000000) ; only watch if directory
+(define IN_DONT_FOLLOW #x02000000) ; do not follow symlink
+(define IN_EXCL_UNLINK #x04000000) ; exclude events on unlinked objects
+(define IN_MASK_ADD #x20000000) ; add to the mask of an existing watch
+(define IN_ISDIR #x40000000) ; event occurred against directory
+(define IN_ONESHOT #x80000000) ; only send event once
+
+(define mask/symbol (make-hash-table))
+(define symbol/mask (make-hash-table))
+
+(for-each (match-lambda
+ ((sym mask)
+ (hashq-set! symbol/mask sym mask)
+ (hashv-set! mask/symbol mask sym)))
+ `((access ,IN_ACCESS)
+ (modify ,IN_MODIFY)
+ (attrib ,IN_ATTRIB)
+ (close-write ,IN_CLOSE_WRITE)
+ (close-no-write ,IN_CLOSE_NOWRITE)
+ (open ,IN_OPEN)
+ (moved-from ,IN_MOVED_FROM)
+ (moved-to ,IN_MOVED_TO)
+ (create ,IN_CREATE)
+ (delete ,IN_DELETE)
+ (delete-self ,IN_DELETE_SELF)
+ (move-self ,IN_MOVE_SELF)
+ (only-dir ,IN_ONLYDIR)
+ (dont-follow ,IN_DONT_FOLLOW)
+ (exclude-unlink ,IN_EXCL_UNLINK)
+ (is-directory ,IN_ISDIR)
+ (once ,IN_ONESHOT)))
+
+(define (symbol->mask sym)
+ (hashq-ref symbol/mask sym))
+
+(define (mask->symbol sym)
+ (hashq-ref mask/symbol sym))
+
+(define-record-type <inotify>
+ (%make-inotify port buffer buffer-pointer watches)
+ inotify?
+ (port inotify-port)
+ (buffer inotify-buffer)
+ (buffer-pointer inotify-buffer-pointer)
+ (watches inotify-watches))
+
+(define-record-type <inotify-watch>
+ (make-inotify-watch id file-name owner)
+ inotify-watch?
+ (id inotify-watch-id)
+ (file-name inotify-watch-file-name)
+ (owner inotify-watch-owner))
+
+(define-record-type <inotify-event>
+ (make-inotify-event watch type cookie file-name)
+ inotify-event?
+ (watch inotify-event-watch)
+ (type inotify-event-type)
+ (cookie inotify-event-cookie)
+ (file-name inotify-event-file-name))
+
+(define (display-inotify inotify port)
+ (format port "#<inotify port: ~a>" (inotify-port inotify)))
+
+(define (display-inotify-watch watch port)
+ (format port "#<inotify-watch id: ~d file-name: ~a>"
+ (inotify-watch-id watch)
+ (inotify-watch-file-name watch)))
+
+(define (display-inotify-event event port)
+ (format port "#<inotify-event type: ~s cookie: ~d file-name: ~a watch: ~a>"
+ (inotify-event-type event)
+ (inotify-event-cookie event)
+ (inotify-event-file-name event)
+ (inotify-event-watch event)))
+
+(set-record-type-printer! <inotify> display-inotify)
+(set-record-type-printer! <inotify-watch> display-inotify-watch)
+(set-record-type-printer! <inotify-event> display-inotify-event)
+
+(define (make-inotify)
+ (let ((fd (inotify-init))
+ (buffer (make-bytevector 4096)))
+ (%make-inotify (fdopen fd "r")
+ buffer
+ (bytevector->pointer buffer)
+ (make-hash-table))))
+
+(define (inotify-fd inotify)
+ (port->fdes (inotify-port inotify)))
+
+(define (absolute-file-name file-name)
+ (if (absolute-file-name? file-name)
+ file-name
+ (string-append (getcwd) "/" file-name)))
+
+(define (inotify-add-watch! inotify file-name modes)
+ (let* ((abs-file-name (absolute-file-name file-name))
+ (wd (inotify-add-watch (inotify-fd inotify)
+ (string->pointer abs-file-name)
+ (apply logior (map symbol->mask modes))))
+ (watch (make-inotify-watch wd abs-file-name inotify)))
+ (hashv-set! (inotify-watches inotify) wd watch)
+ watch))
+
+(define (inotify-watch-remove! watch)
+ (inotify-rm-watch (inotify-fd (inotify-watch-owner watch))
+ (inotify-watch-id watch))
+ (hashv-remove! (inotify-watches (inotify-watch-owner watch))
+ (inotify-watch-id watch)))
+
+(define (inotify-pending-events? inotify)
+ ;; Sometimes an interrupt happens during the char-ready? call and an
+ ;; exception is thrown. Just return #f in that case and move on
+ ;; with life.
+ (false-if-exception (char-ready? (inotify-port inotify))))
+
+(define (read-int port buffer)
+ (get-bytevector-n! port buffer 0 (sizeof int))
+ (bytevector-sint-ref buffer 0 (native-endianness) (sizeof int)))
+
+(define (read-uint32 port buffer)
+ (get-bytevector-n! port buffer 0 (sizeof uint32))
+ (bytevector-uint-ref buffer 0 (native-endianness) (sizeof uint32)))
+
+(define (read-string port buffer buffer-pointer length)
+ (and (> length 0)
+ (begin
+ (get-bytevector-n! port buffer 0 length)
+ (pointer->string buffer-pointer))))
+
+(define (inotify-read-event inotify)
+ (let* ((port (inotify-port inotify))
+ (buffer (inotify-buffer inotify))
+ (wd (read-int port buffer))
+ (event-mask (read-uint32 port buffer))
+ (cookie (read-uint32 port buffer))
+ (len (read-uint32 port buffer))
+ (name (read-string port buffer (inotify-buffer-pointer inotify) len)))
+ (make-inotify-event (hashv-ref (inotify-watches inotify) wd)
+ (mask->symbol event-mask) cookie name)))