#| -*-Scheme-*-

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    2017, 2018, 2019 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

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it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
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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.

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|#

;;;; Version Control: CVS

(declare (usual-integrations))

(define vc-type:cvs
  (make-vc-type 'CVS "CVS" "\$Id\$"))

(define (cvs-master? master)
  (eq? vc-type:cvs (vc-master-type master)))

(define (cvs-directory workfile)
  (subdirectory-pathname workfile "CVS"))

(define (get-cvs-workfile-revision master error?)
  (let ((tokens (find-cvs-entry master)))
    (if tokens
	(cadr tokens)
	(and error?
	     (error "Workfile has no version:" (vc-master-workfile master))))))

(define (find-cvs-entry master)
  (let ((pathname (vc-master-pathname master)))
    (read-cached-value-1 master 'CVS-ENTRY pathname
      (lambda (time)
	time
	(%find-cvs-entry pathname (vc-master-workfile master))))))

(define (%find-cvs-entry pathname workfile)
  (let ((line
	 (find-cvs-line pathname
			(string-append "/" (file-namestring workfile) "/"))))
    (and line
	 (let ((tokens (cdr (burst-string line #\/ #f))))
	   (and (fix:= 5 (length tokens))
		tokens)))))

(define (cvs-workfile-protected? workfile)
  (string-prefix? "-r-"
		  (file-attributes/mode-string (file-attributes workfile))))

(define (cvs-file-edited? master)
  (let ((pathname
	 (merge-pathnames "Baserev"
			  (directory-pathname (vc-master-pathname master)))))
    (read-cached-value-1 master 'CVS-FILE-EDITED? pathname
      (lambda (time)
	time
	(find-cvs-line pathname
		       (string-append
			"B"
			(file-namestring (vc-master-workfile master))
			"/"))))))

(define (find-cvs-line pathname prefix)
  (and (file-readable? pathname)
       (call-with-input-file pathname
	 (lambda (port)
	   (let loop ()
	     (let ((line (read-line port)))
	       (and (not (eof-object? line))
		    (if (string-prefix? prefix line)
			line
			(loop)))))))))

(define (cvs-status master)
  (if (vc-cvs-stay-local? master)
      (if (vc-backend-workfile-modified? master)
	  'LOCALLY-MODIFIED
	  'UP-TO-DATE)
      (get-cvs-status master
	(lambda (m)
	  (if (re-search-forward "^File: [^ \t]+[ \t]+Status: \\(.*\\)" m)
	      (convert-cvs-status
	       (extract-string (re-match-start 1) (re-match-end 1)))
	      'UNKNOWN)))))

(define (cvs-default-revision master)
  (get-cvs-status master
    (lambda (m)
      (and (re-search-forward cvs-status-regexp m)
	   (extract-string (re-match-start 2) (re-match-end 2))))))

(define cvs-status-regexp
  "\\(RCS Version\\|RCS Revision\\|Repository revision\\):[ \t]+\\([0-9.]+\\)")

(define (get-cvs-status master parse-output)
  (vc-run-command master
		  `((BUFFER " *vc-status*"))
		  "cvs" "status"
		  (file-pathname (vc-master-workfile master)))
  (parse-output (buffer-start (find-or-create-buffer " *vc-status*"))))

(define (convert-cvs-status status)
  (cond ((string-ci=? status "Up-to-date")
	 'UP-TO-DATE)
	((string-ci=? status "Locally Modified")
	 'LOCALLY-MODIFIED)
	((or (string-ci=? status "Locally Added")
	     (string-ci=? status "New file!"))
	 'LOCALLY-ADDED)
	((string-ci=? status "Locally Removed")
	 'LOCALLY-REMOVED)
	((or (string-ci=? status "Needs Checkout")
	     (string-ci=? status "Needs Patch"))
	 'NEEDS-CHECKOUT)
	((string-ci=? status "Needs Merge")
	 'NEEDS-MERGE)
	((or (string-ci=? status "File had conflicts on merge")
	     (string-ci=? status "Unresolved Conflict"))
	 'UNRESOLVED-CONFLICT)
	(else
	 'UNKNOWN)))

(define (cvs-rev-switch revision)
  (and revision
       (list "-r" revision)))

(define (vc-cvs-stay-local? master)
  (ref-variable vc-cvs-stay-local (vc-workfile-buffer master #f)))

(define (vc-cvs-workfile-mtime-string master)
  (read-cached-value-2 master 'CVS-MTIME-STRING
		       (vc-master-pathname master)
		       (vc-master-workfile master)
    (lambda (tm tw)
      (and tm tw
	   (let ((entry (find-cvs-entry master)))
	     (and entry
		  (caddr entry)))))))

(define (set-vc-cvs-workfile-mtime-string! master tm tw modified?)
  (if (and tm tw (not modified?))
      (begin
	;; This breaks the READ-CACHED-VALUE-2 abstraction:
	(vc-master-put! master 'CVS-MTIME-STRING
			(vector (file-time->global-ctime-string tw) tm tw))
	(let ((buffer (pathname->buffer (vc-master-workfile master))))
	  (if buffer
	      (vc-mode-line master buffer))))))

(define-vc-type-operation 'RELEASE vc-type:cvs
  (lambda ()
    (and (= 0 (vc-run-command #f '() "cvs" "-v"))
	 (re-search-forward "^Concurrent Versions System (CVS) \\([0-9.]+\\)"
			    (buffer-start (get-vc-command-buffer)))
	 (extract-string (re-match-start 1) (re-match-end 1)))))

(define-vc-type-operation 'FIND-MASTER vc-type:cvs
  (lambda (workfile control-dir)
    (let ((entries-file (merge-pathnames "Entries" control-dir)))
      (and (%find-cvs-entry entries-file workfile)
	   (make-vc-master vc-type:cvs entries-file workfile)))))

(define-vc-type-operation 'VALID? vc-type:cvs
  (lambda (master)
    (get-cvs-workfile-revision master #f)))

(define-vc-type-operation 'DEFAULT-REVISION vc-type:cvs
  (lambda (master)
    (cvs-default-revision master)))

(define-vc-type-operation 'WORKFILE-REVISION vc-type:cvs
  (lambda (master)
    (get-cvs-workfile-revision master #t)))

(define-vc-type-operation 'LOCKING-USER vc-type:cvs
  (lambda (master revision)
    ;; The workfile is "locked" if it is modified.
    ;; We consider the workfile's owner to be the locker.
    (and (or (not revision)
	     (equal? revision (vc-backend-workfile-revision master)))
	 (or (not
	      (let ((t1 (file-modification-time (vc-master-workfile master)))
		    (t2 (vc-cvs-workfile-mtime-string master)))
		(and t1 t2
		     (string=? (file-time->global-ctime-string t1) t2))))
	     (cvs-file-edited? master))
         (let ((attributes (file-attributes (vc-master-workfile master))))
           (and attributes
                (unix/uid->string (file-attributes/uid attributes)))))))

(define-vc-type-operation 'WORKFILE-MODIFIED? vc-type:cvs
  (lambda (master)
    (read-cached-value-2 master 'MODIFIED?
			 (vc-master-pathname master)
			 (vc-master-workfile master)
      (lambda (tm tw)
	(if (and tm tw
		 (let ((ts (vc-cvs-workfile-mtime-string master)))
		   (and ts
			(string=? ts (file-time->global-ctime-string tw)))))
	    #f
	    (or (vc-cvs-stay-local? master)
		(let ((modified? (vc-backend-diff master #f #f #t)))
		  (set-vc-cvs-workfile-mtime-string! master tm tw modified?)
		  modified?)))))))

(define-vc-type-operation 'NEXT-ACTION vc-type:cvs
  (lambda (master)
    (case (cvs-status master)
      ((UP-TO-DATE)
       (if (or (vc-workfile-buffer-modified? master)
	       (cvs-file-edited? master))
	   'CHECKIN
	   'UNMODIFIED))
      ((NEEDS-CHECKOUT NEEDS-MERGE) 'MERGE)
      ((LOCALLY-MODIFIED LOCALLY-ADDED LOCALLY-REMOVED) 'CHECKIN)
      ((UNRESOLVED-CONFLICT) 'RESOLVE-CONFLICT)
      (else
       (error "Unable to determine CVS status of file:"
	      (vc-master-workfile master))))))

(define-vc-type-operation 'KEEP-WORKFILES? vc-type:cvs
  (lambda (master)
    master
    #t))

(define-vc-type-operation 'WORKFILE-STATUS-STRING vc-type:cvs
  (lambda (master)
    (case (cvs-status master)
      ((LOCALLY-MODIFIED) "modified")
      ((LOCALLY-ADDED) "added")
      ((NEEDS-CHECKOUT) "patch")
      ((NEEDS-MERGE) "merge")
      ((UNRESOLVED-CONFLICT) "conflict")
      (else #f))))

(define-vc-type-operation 'CONTROL-DIRECTORY vc-type:cvs
  (lambda (directory)
    (let ((cd (cvs-directory directory)))
      (and (file-directory? cd)
	   cd))))

(define-vc-type-operation 'STEAL vc-type:cvs
  (lambda (master revision)
    master revision
    (error "You cannot steal a CVS lock; there are no CVS locks to steal.")))

(define-vc-type-operation 'REGISTER vc-type:cvs
  (lambda (workfile revision comment keep?)
    revision keep?			;always keep file.
    (with-vc-command-message workfile "Registering"
      (lambda ()
	(vc-run-command workfile '() "cvs" "add"
			"-m" comment
			(file-pathname workfile))))))

(define-vc-type-operation 'CHECKOUT vc-type:cvs
  (lambda (master revision lock? workfile)
    (let ((workfile* (file-pathname (vc-master-workfile master))))
      (with-vc-command-message master "Checking out"
	(lambda ()
	  (cond (workfile
		 ;; CVS makes it difficult to check a file out into
		 ;; anything but the working file.
		 (delete-file-no-errors workfile)
		 (vc-run-shell-command master '() "cvs" "update" "-p"
				       (cvs-rev-switch revision)
				       workfile*
				       ">"
				       workfile))
		(revision
		 (vc-run-command master '() "cvs" (and lock? "-w") "update"
				 (cvs-rev-switch revision)
				 workfile*))
		(else
		 (vc-run-command master '() "cvs" "edit" workfile*))))))))

(define-vc-type-operation 'CHECKIN vc-type:cvs
  (lambda (master revision comment keep?)
    keep?
    (with-vc-command-message master "Checking in"
      (lambda ()
	(bind-condition-handler (list condition-type:editor-error)
	    (lambda (condition)
	      condition
	      (if (eq? 'NEEDS-MERGE (cvs-status master))
		  ;; The CVS output will be on top of this message.
		  (error "Type C-x 0 C-x C-q to merge in changes.")))
	  (lambda ()
	    ;; Explicit check-in to the trunk requires a double check-in
	    ;; (first unexplicit) (CVS-1.3).  [This is copied from Emacs
	    ;; 20.6, but I don't understand it. -- CPH]
	    (if (and revision
		     (not (equal? revision
				  (vc-backend-workfile-revision master)))
		     (trunk-revision? revision))
		(vc-run-command master '() "cvs" "commit"
				"-m" "#intermediate"
				(file-pathname (vc-master-workfile master))))
	    (vc-run-command master '() "cvs" "commit"
			    (cvs-rev-switch revision)
			    "-m" comment
			    (file-pathname (vc-master-workfile master)))))
	;; If this was an explicit check-in, remove the sticky tag.
	(if revision
	    (vc-run-command master '() "cvs" "update" "-A"
			    (file-pathname (vc-master-workfile master))))))))

(define-vc-type-operation 'REVERT vc-type:cvs
  (lambda (master)
    (with-vc-command-message master "Reverting"
      (lambda ()
	(let ((workfile (vc-master-workfile master)))
	  (if (cvs-file-edited? master)
	      (vc-run-command master '() "cvs" "unedit"
			      (file-pathname workfile))
	      (begin
		(delete-file-no-errors workfile)
		(vc-run-command master '() "cvs" "update"
				(file-pathname workfile)))))))))

(define-vc-type-operation 'DIFF vc-type:cvs
  (lambda (master rev1 rev2 simple?)
    (= 1
       (vc-run-command master
		       (get-vc-diff-options simple?)
		       "cvs"
		       "diff"
		       (if simple?
			   (and (diff-brief-available?) "--brief")
			   (gc-vc-diff-switches master))
		       (and rev1 (string-append "-r" rev1))
		       (and rev2 (string-append "-r" rev2))
		       (file-pathname (vc-master-workfile master))))))

(define-vc-type-operation 'PRINT-LOG vc-type:cvs
  (lambda (master)
    (vc-run-command master '() "cvs" "log"
		    (file-pathname (vc-master-workfile master)))))

(define-vc-type-operation 'CHECK-LOG-ENTRY vc-type:cvs
  (lambda (master log-buffer)
    master log-buffer
    unspecific))

(define-vc-type-operation 'CHECK-HEADERS vc-type:cvs
  (lambda (master buffer)
    master
    (check-rcs-headers buffer)))

(define (cvs-backend-merge-news master)
  (with-vc-command-message master "Merging changes into"
    (lambda ()
      (let ((workfile (vc-master-workfile master)))
	(vc-run-command master '() "cvs" "update" (file-pathname workfile))
	(let ((buffer (get-vc-command-buffer))
	      (fn (re-quote-string (file-namestring workfile))))
	  (cond ((re-search-forward
		  (string-append "^\\([CMUP]\\) " fn)
		  (buffer-start buffer))
		 (char=? #\C (extract-right-char (re-match-start 0))))
		((re-search-forward
		  (string-append fn
				 " already contains the differences between ")
		  (buffer-start buffer))
		 ;; Special case: file contents in sync with repository
		 ;; anyhow:
		 #f)
		(else
		 (pop-up-buffer buffer #f)
		 (error "Couldn't analyze cvs update result."))))))))