(lmdb): Initial higher-level API

2 files changed, 108 insertions, 1 deletions

diff --git a/lmdb.scm b/lmdb.scm
index e933e20..8c4982d 100644
--- a/lmdb.scm
+++ b/lmdb.scm
@@ -3,4 +3,69 @@
 ; SPDX-License-Identifier: GPL-3.0-or-later
 
 (define-module (lmdb)
+  #:use-module (srfi srfi-9)
   #:use-module (lmdb low-level))
+
+(define-record-type <lmdb-db>
+  (&make-lmdb-db env dbi closed?)
+  lmdb-db?
+  (env lmdb-db-env)
+  (dbi lmdb-db-dbi)
+  (closed? lmdb-db-closed? set-lmdb-db-closed?))
+
+(define* (lmdb-open path #:key db-name)
+
+  ;; create and open environment
+  (define env (mdb-env-create))
+  (mdb-env-open env path)
+
+  ;; create a transaction and open a database
+  (define txn (mdb-txn-begin env))
+  (define dbi (mdb-dbi-open txn))
+
+  ;; commit transaction so that database handle can now be used from other
+  ;; transactions
+  (mdb-txn-commit txn)
+
+  (&make-lmdb-db env dbi #f))
+
+(define (lmdb-close db)
+  (mdb-env-close (lmdb-db-env db))
+  (set-lmdb-db-closed? db #t))
+
+(define lmdb-transaction?
+  mdb-txn?)
+
+(define (lmdb-put! db key value)
+  (let ((txn (mdb-txn-begin (lmdb-db-env db))))
+    (mdb-put txn (lmdb-db-dbi db)
+             (make-mdb-val key)
+             (make-mdb-val value))
+    (mdb-txn-commit txn)))
+
+(define (lmdb-get db key)
+  (let* ((txn (mdb-txn-begin (lmdb-db-env db)))
+         (val (mdb-get txn (lmdb-db-dbi db)
+                       (make-mdb-val key))))
+    (mdb-txn-abort txn)
+    (mdb-val-data val)))
+
+(define (lmdb-delete! db key)
+  (let ((txn (mdb-txn-begin (lmdb-db-env db))))
+    (mdb-del txn (lmdb-db-dbi db)
+             (make-mdb-val key))
+    (mdb-txn-commit txn)))
+
+(define db (lmdb-open "./testdb"))
+
+(lmdb-db? db)
+
+(use-modules (rnrs bytevectors))
+
+(lmdb-put! db
+           (string->utf8 "hi")
+           (string->utf8 "blupsblups"))
+
+(lmdb-get db (string->utf8 "hi"))
+
+(lmdb-delete! db (string->utf8 "hi"))
diff --git a/lmdb/low-level.scm b/lmdb/low-level.scm
index 56bdf49..30ddba6 100644
--- a/lmdb/low-level.scm
+++ b/lmdb/low-level.scm
@@ -12,7 +12,32 @@
 
   #:use-module (rnrs bytevectors)
 
-  #:use-module (lmdb internal))
+  #:use-module (lmdb internal)
+
+  #:export (<mdb-env>
+            mdb-env?
+            mdb-env-create
+            mdb-env-open
+            mdb-env-close
+
+            <mdb-txn>
+            mdb-txn?
+            mdb-txn-begin
+            mdb-txn-abort
+            mdb-txn-commit
+
+            <mdb-dbi>
+            mdb-dbi?
+            mdb-dbi-open
+
+            <mdb-val>
+            mdb-val?
+            make-mdb-val
+            mdb-val-data
+
+            mdb-put
+            mdb-get
+            mdb-del))
 
 ;; MDB_env
 
@@ -193,3 +218,20 @@
           data-ptr)
     ;; wrap data as <mdb-val>
     (wrap-mdb-val data-ptr)))
+
+(define (mdb-del txn dbi key)
+  "Delete items from a database"
+  (let ((proc (liblmdb-func "mdb_del"
+                            (list
+                             ;; MDB_txn* txn
+                             '*
+                             ;; MDB_dbi* dbi
+                             '*
+                             ;; MDB_val* key
+                             '*
+                             ;; MDB_val* data
+                             '*))))
+    (proc (unwrap-mdb-txn txn)
+          (unwrap-mdb-dbi dbi)
+          (unwrap-mdb-val key)
+          (make-pointer 0))))