#| -*-Scheme-*-

$Id: berkeley-db.scm,v 1.6 2007/01/05 21:19:28 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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 2 of the License, or (at
your option) any later version.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

|#

;;;; Berkeley DB Interface
;;; package: (runtime berkeley-db)

(declare (usual-integrations))

(define-primitives
  (db4:db-close 2)
  (db4:db-create 3)
  (db4:db-del 4)
  (db4:db-env-close 2)
  (db4:db-env-create 2)
  (db4:db-env-get-home 2)
  (db4:db-env-get-open-flags 2)
  (db4:db-env-lock-get 6)
  (db4:db-env-lock-id 2)
  (db4:db-env-lock-id-free 2)
  (db4:db-env-lock-put 2)
  (db4:db-env-open 4)
  (db4:db-env-txn-begin 4)
  (db4:db-get 5)
  (db4:db-get-dbname 2)
  (db4:db-get-env 2)
  (db4:db-get-open-flags 2)
  (db4:db-get-pagesize 2)
  (db4:db-get-transactional 2)
  (db4:db-get-type 2)
  (db4:db-open 7)
  (db4:db-put 5)
  (db4:db-strerror 1)
  (db4:db-txn-abort 1)
  (db4:db-txn-commit 2)
  (db4:dbt-size 1)
  (db4:init-dbt 4)
  (db4:name->rc 1)
  (db4:rc->name 1)
  (db4:sizeof-db-lock 0)
  (db4:sizeof-dbt 0))

(define-integrable DB_CXX_NO_EXCEPTIONS	#x00000002)
(define-integrable DB_FORCE		#x00000004)
(define-integrable DB_NOMMAP		#x00000008)
(define-integrable DB_RDONLY		#x00000010)
(define-integrable DB_RECOVER		#x00000020)
(define-integrable DB_THREAD		#x00000040)
(define-integrable DB_TRUNCATE		#x00000080)
(define-integrable DB_TXN_NOSYNC	#x00000100)
(define-integrable DB_TXN_NOT_DURABLE	#x00000200)
(define-integrable DB_USE_ENVIRON	#x00000400)
(define-integrable DB_USE_ENVIRON_ROOT	#x00000800)
(define-integrable DB_AUTO_COMMIT	#x01000000)
(define-integrable DB_DIRTY_READ	#x02000000)
(define-integrable DB_NO_AUTO_COMMIT	#x04000000)

;; Flags for DB4:DB-ENV-CREATE
(define-integrable DB_RPCCLIENT		#x00000001)

;; Flags for DB4:DB-CREATE
(define-integrable DB_REP_CREATE	#x00000001)
(define-integrable DB_XA_CREATE		#x00000002)

;; Flags for DB4:DB-ENV-OPEN
(define-integrable DB_INIT_CDB		#x00001000)
(define-integrable DB_INIT_LOCK		#x00002000)
(define-integrable DB_INIT_LOG		#x00004000)
(define-integrable DB_INIT_MPOOL	#x00008000)
(define-integrable DB_INIT_REP		#x00010000)
(define-integrable DB_INIT_TXN		#x00020000)
(define-integrable DB_JOINENV		#x00040000)
(define-integrable DB_LOCKDOWN		#x00080000)
(define-integrable DB_PRIVATE		#x00100000)
(define-integrable DB_RECOVER_FATAL	#x00200000)
(define-integrable DB_SYSTEM_MEM	#x00400000)

;; Flags for DB4:DB-OPEN
(define-integrable DB_EXCL		#x00001000)
(define-integrable DB_FCNTL_LOCKING	#x00002000)
(define-integrable DB_RDWRMASTER	#x00004000)
(define-integrable DB_WRITEOPEN		#x00008000)

;; Flags for DB4:DB-ENV-TXN-BEGIN
(define-integrable DB_TXN_NOWAIT	#x00001000)
(define-integrable DB_TXN_SYNC		#x00002000)

;; Flags for DB4:DB-GET, DB4:DB-PUT, DB4:DB-DEL
#;(define-integrable DB_DIRTY_READ	#x02000000)
(define-integrable DB_MULTIPLE		#x04000000)
(define-integrable DB_MULTIPLE_KEY	#x08000000)
(define-integrable DB_RMW		#x10000000)

;; db_locktype_t enumeration:
(define-integrable DB_LOCK_NG 0)
(define-integrable DB_LOCK_READ 1)
(define-integrable DB_LOCK_WRITE 2)
(define-integrable DB_LOCK_WAIT 3)
(define-integrable DB_LOCK_IWRITE 4)
(define-integrable DB_LOCK_IREAD 5)
(define-integrable DB_LOCK_IWR 6)
(define-integrable DB_LOCK_DIRTY 7)
(define-integrable DB_LOCK_WWRITE 8)

(define-syntax pcall
  (sc-macro-transformer
   (lambda (form environment)
     (if (syntax-match? '(identifier * expression) (cdr form))
	 `(LET ((RC
		 (,(close-syntax (cadr form) environment)
		  ,@(map (lambda (expr)
			   (close-syntax expr environment))
			 (cddr form)))))
	    (IF (NOT (= RC 0))
		(BDB-ERROR RC ',(cadr form))))))))

(define condition-type:bdb-error
  (make-condition-type 'BDB-ERROR condition-type:error '(RC PRIMITIVE)
    (lambda (condition port)
      (let ((rc (access-condition condition 'RC)))
	(write-string "Berkeley DB error in primitive " port)
	(write (access-condition condition 'PRIMITIVE) port)
	(write-string ": " port)
	(write-string (db4:db-strerror rc) port)
	(write-string " (" port)
	(write (or (db4:rc->name rc) rc) port)
	(write-string ")." port)))))

(define bdb-error
  (condition-signaller condition-type:bdb-error
		       '(RC PRIMITIVE)
		       standard-error-handler))

(define-record-type <bdb>
    (make-bdb handle)
    bdb?
  (handle bdb-handle set-bdb-handle!))

(define-record-type <bdb-env>
    (make-bdb-env handle)
    bdb-env?
  (handle bdb-env-handle set-bdb-env-handle!)
  (ids bdb-env-ids))

(define-record-type <bdb-txn>
    (make-bdb-txn handle)
    bdb-txn?
  (handle bdb-txn-handle set-bdb-txn-handle!))

(define-record-type <bdb-id>
    (make-bdb-id handle)
    bdb-id?
  (handle bdb-id-handle set-bdb-id-handle!))

(define interface-initialized? #f)
(define dbs)
(define envs)
(define txns)
(define dbt-length)
(define db-lock-length)

(define (bdb-available?)
  (load-library-object-file "prdb4" #f)
  (and (implemented-primitive-procedure? db4:db-create)
       (begin
	 (if (not interface-initialized?)
	     (begin
	       (set! dbs
		     (make-gc-finalizer db4:db-close
					bdb?
					bdb-handle
					set-bdb-handle!))
	       (set! envs
		     (make-gc-finalizer db4:db-env-close
					bdb-env?
					bdb-env-handle
					set-bdb-env-handle!))
	       (set! txns
		     (make-gc-finalizer db4:db-txn-abort
					bdb-txn?
					bdb-txn-handle
					set-bdb-txn-handle!))
	       (set! dbt-length (db4:sizeof-dbt))
	       (set! db-lock-length (db4:sizeof-db-lock))
	       (set! interface-initialized? #t)))
	 #t)))

(define (guarantee-bdb-available)
  (if (not (bdb-available?))
      (error "No Berkeley DB support in this sytem.")))

(define (create-bdb env flags)
  (guarantee-bdb-available)
  (make-gc-finalized-object dbs
			    (lambda (p)
			      (pcall db4:db-create
				     (and env (bdb-env-handle env))
				     flags
				     p))
			    make-bdb))

(define (open-bdb db txn filename db-name type flags mode)
  (pcall db4:db-open
	 (bdb-handle db)
	 (and txn (bdb-txn-handle txn))
	 (and filename (->namestring (merge-pathnames filename)))
	 db-name
	 type
	 flags
	 mode))

(define (bdb-names db)
  (let ((p (cons #f #f)))
    (pcall db4:db-get-dbname (bdb-handle db) p)
    (values (car p) (cdr p))))

(define (bdb-open-flags db)
  (let ((p (cons #f #f)))
    (pcall db4:db-get-open-flags (bdb-handle db) p)
    (car p)))

(define (bdb-transactional? db)
  (let ((p (cons #f #f)))
    (pcall db4:db-get-transactional (bdb-handle db) p)
    (car p)))

(define (close-bdb db flags)
  (pcall db4:db-close (bdb-handle db) flags))

(define (string->dbt string)
  (let ((dbt (make-dbt)))
    (db4:init-dbt dbt string #f #f)
    dbt))

(define (string->dbt-partial string start length)
  (let ((dbt (make-dbt)))
    (db4:init-dbt dbt string start length)
    dbt))

(define (make-dbt)
  (make-string dbt-length))

(define rc:db_notfound
  (db4:name->rc 'db_notfound))

(define rc:enomem
  (db4:name->rc 'enomem))

(define (bdb-get db txn key flags)
  (let ((db (bdb-handle db))
	(txn (and txn (bdb-txn-handle txn)))
	(key (string->dbt key))
	(datum (make-dbt)))
    (db4:init-dbt datum "" #f #f)
    (let ((rc (db4:db-get db txn key datum flags)))
      (cond ((= rc rc:db_notfound)
	     #f)
	    ((= rc rc:enomem)
	     (let ((string (make-string (db4:dbt-size datum))))
	       (db4:init-dbt datum string #f #f)
	       (pcall db4:db-get db txn key datum flags)
	       string))
	    ((= rc 0)
	     (make-string 0))
	    (else
	     (bdb-error rc 'db4:db-get))))))

(define (bdb-get-partial db txn key flags start length)
  (let ((string (make-string length)))
    (let ((rc
	   (db4:db-get (bdb-handle db)
		       (and txn (bdb-txn-handle txn))
		       (string->dbt key)
		       (string->dbt-partial string start length)
		       flags)))
      (cond ((= rc 0) string)
	    ((= rc rc:db_notfound) #f)
	    (else (bdb-error rc 'db4:db-get))))))

(define (bdb-put db txn key datum flags)
  (pcall db4:db-put
	 (bdb-handle db)
	 (and txn (bdb-txn-handle txn))
	 (string->dbt key)
	 (string->dbt datum)
	 flags))

(define (bdb-put-partial db txn key datum flags start length)
  (pcall db4:db-put
	 (bdb-handle db)
	 (and txn (bdb-txn-handle txn))
	 (string->dbt key)
	 (string->dbt-partial datum start length)
	 flags))

(define (bdb-delete db txn key flags)
  (let ((rc
	 (db4:db-del (bdb-handle db)
		     (and txn (bdb-txn-handle txn))
		     (string->dbt key)
		     flags)))
    (cond ((= rc 0) #t)
	  ((= rc rc:db_notfound) #f)
	  (else (bdb-error rc 'db4:db-del)))))

(define (create-bdb-env flags)
  (guarantee-bdb-available)
  (make-gc-finalized-object
   envs
   (lambda (p) (pcall db4:db-env-create flags p))
   (lambda (handle)
     (make-bdb-env handle
		   (make-gc-finalizer (lambda (id)
					(db4:db-env-lock-id-free handle id))
				      bdb-id?
				      bdb-id-handle
				      set-bdb-id-handle!)))))

(define (open-bdb-env env home flags mode)
  (pcall db4:db-env-open
	 (bdb-env-handle env)
	 (->namestring (merge-pathnames home))
	 flags
	 mode))

(define (bdb-env-home env)
  (let ((p (cons #f #f)))
    (pcall db4:db-env-get-home (bdb-env-handle env) p)
    (car p)))

(define (bdb-env-open-flags env)
  (let ((p (cons #f #f)))
    (pcall db4:db-env-get-open-flags (bdb-env-handle env) p)
    (car p)))

(define (close-bdb-env env flags)
  (pcall db4:db-env-close (bdb-env-handle env) flags))

(define (bdb-env-lock-id env)
  (make-gc-finalized-object
   (bdb-env-ids env)
   (lambda (p) (pcall db4:db-env-lock-id (bdb-env-handle env) p))
   make-bdb-id))

(define (bdb-env-lock-id-free env id)
  (pcall db4:db-env-lock-id-free (bdb-env-handle env) id))

(define (bdb-env-lock-get env id flags object lock-mode)
  (let ((lock (make-string db-lock-length)))
    (pcall db4:db-env-lock-get
	   (bdb-env-handle env)
	   id
	   flags
	   (string->dbt object)
	   lock-mode
	   lock)
    lock))

(define (bdb-env-lock-put env lock)
  (pcall db4:db-env-lock-put (bdb-env-handle env) lock))

(define (bdb-env-txn-begin env txn flags)
  (make-gc-finalized-object
   txns
   (lambda (p)
     (pcall db4:db-env-txn-begin
	    (bdb-env-handle env)
	    (and txn (bdb-txn-handle txn))
	    flags
	    p))
   make-bdb-txn))

(define (bdb-txn-commit txn flags)
  (pcall db4:db-txn-commit (bdb-txn-handle txn) flags))

(define (bdb-txn-abort txn)
  (pcall db4:db-txn-abort (bdb-txn-handle txn)))