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@JonathanGTH
Created April 18, 2016 04:28
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(ns clj-lmdb.core
(:refer-clojure :exclude [get]) ; suppress the shadowing warning
(:require [clojure.core :as core])
(:import [org.fusesource.lmdbjni Database Env]
[org.fusesource.lmdbjni Constants]))
(declare ^:dynamic *txn*)
(declare ^:dynamic *db*)
(defprotocol LMDB
"A simple protocol for getters and setters
w/ LBDB"
(get-env [this])
(get-db [this])
(items [this])
(items-from [this from]))
(deftype DB [env db]
LMDB
(get-env [this] env)
(get-db [this] db)
(items [this]
(let [entries (-> *db*
(.iterate *txn*)
iterator-seq)]
(map
(fn [e]
(let [k (.getKey e)
v (.getValue e)]
[(Constants/string k)
(Constants/string v)]))
entries)))
(items-from [this from]
(let [entries (-> *db*
(.seek *txn*
(Constants/bytes from))
iterator-seq)]
(map
(fn [e]
(let [k (.getKey e)
v (.getValue e)]
[(Constants/string k)
(Constants/string v)]))
entries))))
(defn make-db
[dir-path]
(let [env (Env. dir-path)
db (.openDatabase env)]
(DB. env db)))
(defmacro with-write-txn
[db-record & body]
`(let [db-record# ~db-record
env# (get-env db-record#)
db# (get-db db-record#)
txn# (.createWriteTransaction env#)]
(binding [*db* db#
*txn* txn#]
~@body)
(.commit txn#)))
(defmacro with-read-txn
[db-record & body]
`(let [db-record# ~db-record
env# (get-env db-record#)
db# (get-db db-record#)
txn# (.createReadTransaction env#)]
(binding [*txn* txn#
*db* db#]
~@body)
(.abort txn#)))
(defn put!
([k v]
(.put *db*
*txn*
(Constants/bytes k)
(Constants/bytes v)))
([db-record k v]
(let [db (get-db db-record)]
(.put db
(Constants/bytes k)
(Constants/bytes v)))))
(defn get!
([k]
(Constants/string
(.get *db*
*txn*
(Constants/bytes k))))
([db-record k]
(let [db (get-db db-record)]
(Constants/string
(.get db
(Constants/bytes k))))))
(defn delete!
([k]
(.delete *db*
*txn*
(Constants/bytes k)))
([db-record k]
(let [db (get-db db-record)]
(.delete db
(Constants/bytes k)))))
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