Chicken Scheme bindings for the Lightning Memory-Mapped Database Manager (LMDB) (http://symas.com/mdb/doc/index.html) database management library.
(db-open filename [key: enckey] [mapsize: size])
Opens or creates LMDB database with optional encryption key and map size.
(db-close db)
Closes LMDB database handle.
(db-begin db [dbname: dbname] [flags: 0])
Begins LMDB transaction with optional database name and flags returned by db-flags.
Commits and ends LMDB transaction.
(db-flags flag-name ...)
Returns a bit mask that represents LMDB environment flags. The flag name is one of the following keywords:
#:fixed-map: mmap at a fixed address#:no-subdirectory: no environment directory#:read-only: read only#:write-map: use writable mmap#:no-meta-sync: don't fsync metapage after commit#:no-sync: don't fsync after commit#:map-async: use asynchronous sync with#:write-mapis used#:no-lock: don't do locking#:no-read-ahead: don't do readahead
(db-abort db)
Aborts LMDB transaction.
(db-delete db key)
Removes a key from the database.
(db-delete-database dbname)
Deletes LMDB database.
(db-ref db key)
Looks up key in database.
(db-set! db key value)
Sets a key-value pair in the database.
(db-count db)
Returns number of key-value pairs in database.
(db-keys db)
Returns a list of database keys.
(db-values db)
Returns a list of database values.
(db-key-len m)
Returns the length of the current key.
(db-value-len m)
Returns the length of the current value.
(db-key m buf)
Copies the current key to the specified blob.
(db-value m buf)
Copies the current value to the specified blob.
(db-fold f init db)
Fold over the keys and values in the database.
(db-for-each f db)
Iterate over the keys and values in the database.
(hash-table->db t dbfile [enckey])
Saves SRFI-69 hash table to database.
(db->hash-table dbfile [enckey])
Load database into SRFI-69 hash table.
;; lmdb encrypted key-value creation and lookup
(let* ((fname (make-pathname "." "mydb.mdb"))
(keys (list "k1" 'k2 '(k3)))
(values (list 'one 2 "three"))
(cryptokey (string->blob "1234"))
(mm (db-open fname key: cryptokey)))
(db-begin mm)
(let loop ((ks keys) (vs values))
(if (> (length ks) 0)
(begin
(db-set! mm (string->blob (->string (car ks))) (string->blob (->string (car vs))))
(loop (cdr ks) (cdr vs)))))
(db-end mm)
(db-begin mm)
(let ((res (let loop ((ks keys) (vs values))
(if (= (length ks) 0) #t
(let ((v (db-ref mm (string->blob (->string (car ks))))))
(if (not (equal? (string->blob (->string (car vs))) v)) #f
(loop (cdr ks) (cdr vs)))))))
)
(db-end mm)
(db-close mm)
res)
);; lmdb readonly test
(let* ((fname (make-pathname "." "unittest.mdb")))
(db-delete-database fname)
(let ((mm (db-open fname maxdbs: 2)))
(db-begin mm)
;; set foo
(db-set! mm (string->blob "foo") (string->blob "one"))
(db-end mm)
;; reopen as readonly
(db-begin mm flags: (db-flags #:read-only))
;; foo is still set
(test (string->blob "one")
(db-ref mm (string->blob "foo")))
;; cannot set bar
(test 'unknown
(condition-case (db-set! mm (string->blob "bar") (string->blob "two"))
((exn lmdb unknown) 'unknown)))
(db-close mm)))