penpot/backend/src/app/util/blob.clj
Andrey Antukh 68d8a49466 🎉 Add blob encoding v3.
Safer approach (uses json instead of custom binary format) than v2.
2021-03-08 13:30:04 +01:00

129 lines
4.3 KiB
Clojure

;; This Source Code Form is subject to the terms of the Mozilla Public
;; License, v. 2.0. If a copy of the MPL was not distributed with this
;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
;;
;; This Source Code Form is "Incompatible With Secondary Licenses", as
;; defined by the Mozilla Public License, v. 2.0.
;;
;; Copyright (c) 2016-2020 Andrey Antukh <niwi@niwi.nz>
(ns app.util.blob
"A generic blob storage encoding. Mainly used for
page data, page options and txlog payload storage."
(:require
[app.config :as cfg]
[app.util.transit :as t]
[taoensso.nippy :as n])
(:import
java.io.ByteArrayInputStream
java.io.ByteArrayOutputStream
java.io.DataInputStream
java.io.DataOutputStream
com.github.luben.zstd.Zstd
net.jpountz.lz4.LZ4Factory
net.jpountz.lz4.LZ4FastDecompressor
net.jpountz.lz4.LZ4Compressor))
(def lz4-factory (LZ4Factory/fastestInstance))
(declare decode-v1)
(declare decode-v2)
(declare decode-v3)
(declare encode-v1)
(declare encode-v2)
(declare encode-v3)
(def default-version
(:default-blob-version cfg/config 1))
(defn encode
([data] (encode data nil))
([data {:keys [version] :or {version default-version}}]
(case (long version)
1 (encode-v1 data)
2 (encode-v2 data)
3 (encode-v3 data)
(throw (ex-info "unsupported version" {:version version})))))
(defn decode
"A function used for decode persisted blobs in the database."
[^bytes data]
(with-open [bais (ByteArrayInputStream. data)
dis (DataInputStream. bais)]
(let [version (.readShort dis)
ulen (.readInt dis)]
(case version
1 (decode-v1 data ulen)
2 (decode-v2 data ulen)
3 (decode-v3 data ulen)
(throw (ex-info "unsupported version" {:version version}))))))
;; --- IMPL
(defn- encode-v1
[data]
(let [data (t/encode data {:type :json})
dlen (alength ^bytes data)
cp (.fastCompressor ^LZ4Factory lz4-factory)
mlen (.maxCompressedLength cp dlen)
cdata (byte-array mlen)
clen (.compress ^LZ4Compressor cp ^bytes data 0 dlen cdata 0 mlen)]
(with-open [^ByteArrayOutputStream baos (ByteArrayOutputStream. (+ (alength cdata) 2 4))
^DataOutputStream dos (DataOutputStream. baos)]
(.writeShort dos (short 1)) ;; version number
(.writeInt dos (int dlen))
(.write dos ^bytes cdata (int 0) clen)
(.toByteArray baos))))
(defn- decode-v1
[^bytes cdata ^long ulen]
(let [dcp (.fastDecompressor ^LZ4Factory lz4-factory)
udata (byte-array ulen)]
(.decompress ^LZ4FastDecompressor dcp cdata 6 ^bytes udata 0 ulen)
(t/decode udata {:type :json})))
(defn- encode-v2
[data]
(let [data (n/fast-freeze data)
dlen (alength ^bytes data)
mlen (Zstd/compressBound dlen)
cdata (byte-array mlen)
clen (Zstd/compressByteArray ^bytes cdata 0 mlen
^bytes data 0 dlen
8)]
(with-open [^ByteArrayOutputStream baos (ByteArrayOutputStream. (+ (alength cdata) 2 4))
^DataOutputStream dos (DataOutputStream. baos)]
(.writeShort dos (short 2)) ;; version number
(.writeInt dos (int dlen))
(.write dos ^bytes cdata (int 0) clen)
(.toByteArray baos))))
(defn- decode-v2
[^bytes cdata ^long ulen]
(let [udata (byte-array ulen)]
(Zstd/decompressByteArray ^bytes udata 0 ulen
^bytes cdata 6 (- (alength cdata) 6))
(n/fast-thaw udata)))
(defn- encode-v3
[data]
(let [data (t/encode data {:type :json})
dlen (alength ^bytes data)
mlen (Zstd/compressBound dlen)
cdata (byte-array mlen)
clen (Zstd/compressByteArray ^bytes cdata 0 mlen
^bytes data 0 dlen
4)]
(with-open [^ByteArrayOutputStream baos (ByteArrayOutputStream. (+ (alength cdata) 2 4))
^DataOutputStream dos (DataOutputStream. baos)]
(.writeShort dos (short 3)) ;; version number
(.writeInt dos (int dlen))
(.write dos ^bytes cdata (int 0) clen)
(.toByteArray baos))))
(defn- decode-v3
[^bytes cdata ^long ulen]
(let [udata (byte-array ulen)]
(Zstd/decompressByteArray ^bytes udata 0 ulen
^bytes cdata 6 (- (alength cdata) 6))
(t/decode udata {:type :json})))