Add support for custom thaw readers
This commit is contained in:
Peter Taoussanis
parent
8e4cc072e3
commit
99091b0a32
2 changed files with 47 additions and 12 deletions
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@ -23,6 +23,9 @@
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;;;; Data type IDs
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;; **Negative ids reserved for user-defined types**
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(def ^:const id-reserved (int 0))
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;; 1
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(def ^:const id-bytes (int 2))
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(def ^:const id-nil (int 3))
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@ -65,7 +68,7 @@
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(def ^:const id-old-keyword (int 12)) ; as of 2.0.0-alpha5, for str consistecy
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;;;; Freezing
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(defprotocol Freezable (freeze-to-stream* [this stream]))
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(defprotocol Freezable (freeze-to-stream* [this ^DataOutputStream stream]))
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(defmacro ^:private write-id [s id] `(.writeByte ~s ~id))
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(defmacro ^:private write-bytes [s ba]
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@ -173,7 +176,14 @@
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(defn freeze
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"Serializes arg (any Clojure data type) to a byte array. Set :legacy-mode to
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true to produce bytes readble by Nippy < 2.x."
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true to produce bytes readble by Nippy < 2.x.
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For custom types extend the Clojure reader or Nippy's `Freezable` protocol:
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(defrecord MyType [data]
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nippy/Freezable
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(freeze-to-stream* [x stream]
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(.writeByte stream -1) ; Custom type id ∈ [-128, -1]
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(.writeUTF stream (:data x))))"
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^bytes [x & [{:keys [print-dup? password compressor encryptor legacy-mode]
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:or {print-dup? true
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compressor snappy-compressor
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@ -214,10 +224,9 @@
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[(thaw-from-stream s#) (thaw-from-stream s#)])))
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(defn- thaw-from-stream
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[^DataInputStream s]
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[^DataInputStream s & [readers]]
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(let [type-id (.readByte s)]
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(utils/case-eval
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type-id
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(utils/case-eval type-id
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id-reader (read-string (read-utf8 s))
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id-bytes (read-bytes s)
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@ -260,14 +269,22 @@
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(* 2 (.readInt s)) (thaw-from-stream s)))
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id-old-keyword (keyword (.readUTF s))
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(throw (Exception. (str "Failed to thaw unknown type ID: " type-id))))))
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;;; Custom types
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(or (when-let [reader (get readers type-id)]
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(try (reader s)
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(catch Exception e
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(throw (Exception. (str "Reader exception for custom type ID: "
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type-id) e)))))
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(if (neg? type-id)
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(throw (Exception. (str "No reader provided for custom type ID: " type-id)))
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(throw (Exception. (str "Unknown type ID: " type-id))))))))
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(defn thaw-from-stream!
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"Low-level API. Deserializes a frozen object from given DataInputStream to its
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original Clojure data type."
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[data-input-stream & [{:keys [read-eval?]}]]
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[data-input-stream & [{:keys [read-eval? readers]}]]
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(binding [*read-eval* read-eval?]
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(thaw-from-stream data-input-stream)))
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(thaw-from-stream data-input-stream readers)))
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(defn- try-parse-header [ba]
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(when-let [[head-ba data-ba] (utils/ba-split ba 4)]
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@ -280,9 +297,12 @@
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data type. Supports data frozen with current and all previous versions of
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Nippy.
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For custom `Freezable` types provide a `:readers` arg:
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(thaw (freeze (MyType. \"Joe\")) {:readers {-1 (fn [stream] (.readUTF stream))}})
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WARNING: Enabling `:read-eval?` can lead to security vulnerabilities unless
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you are sure you know what you're doing."
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[^bytes ba & [{:keys [read-eval? password compressor encryptor legacy-opts]
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[^bytes ba & [{:keys [read-eval? password compressor encryptor legacy-opts readers]
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:or {legacy-opts {:compressed? true}
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compressor snappy-compressor
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encryptor aes128-encryptor}
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@ -300,7 +320,9 @@
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ba (if password (encryption/decrypt encryptor password ba) ba)
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ba (if compressor (compression/decompress compressor ba) ba)
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stream (DataInputStream. (ByteArrayInputStream. ba))]
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(thaw-from-stream! stream {:read-eval? read-eval?}))
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(thaw-from-stream! stream {:read-eval? read-eval? :readers readers}))
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(catch Exception e
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(cond
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password (ex "Wrong password/encryptor?" e)
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@ -323,7 +345,9 @@
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:else (try (try-thaw-data data-ba head-meta)
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(catch Exception e
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(if legacy-opts
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(try-thaw-data ba nil)
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(try (try-thaw-data ba nil)
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(catch Exception _
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(throw e)))
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(throw e)))))
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;; Header definitely not okay
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@ -406,4 +430,4 @@
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:or {compressed? true}}]
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(thaw ba {:legacy-opts {:compressed? compressed?}
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:read-eval? read-eval?
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:password nil}))
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:password nil}))
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@ -30,4 +30,15 @@
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(thaw (org.iq80.snappy.Snappy/uncompress iq80-ba 0 (alength iq80-ba)))
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(thaw (org.iq80.snappy.Snappy/uncompress xerial-ba 0 (alength xerial-ba))))))
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;;; Custom types
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(defrecord MyType [data]
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nippy/Freezable
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(freeze-to-stream* [x s]
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(.writeByte s -1)
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(.writeUTF s (:data x))))
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(expect Exception (thaw (freeze (MyType. "Joe"))))
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(expect "Joe" (thaw (freeze (MyType. "Joe"))
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{:readers {-1 (fn [s] (.readUTF s))}}))
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(expect (benchmarks/bench {:reader? false})) ; Also tests :cached passwords
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