493 lines
17 KiB
EmacsLisp
493 lines
17 KiB
EmacsLisp
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;;; marshal.el --- eieio extension for automatic (un)marshalling
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;; Copyright (C) 2015 Yann Hodique
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;; Author: Yann Hodique <hodiquey@vmware.com>
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;; Keywords: eieio
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;; Package-Version: 20160807.1954
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;; Version: 0.7.0
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;; URL: https://github.com/sigma/marshal.el
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;; Package-Requires: ((eieio "1.4") (json "1.3") (ht "2.1"))
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;; This file is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; This file is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to
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;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; Inspired by Go tagged structs. 'alist, 'plist and 'json drivers are
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;; provided, but implementing others just requires to inherit from
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;; `marshal-driver'.
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;; Sometimes the types are not enough (for example with lists, whose elements
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;; are not explicitly typed. In those cases, a small extension on top of types
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;; can be used. Like for example :marshal-type (list string)
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;; Examples:
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;; 1. Regular use:
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;; (marshal-defclass plop ()
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;; ((foo :initarg :foo :type string :marshal ((alist . field_foo)))
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;; (bar :initarg :bar :type integer :marshal ((alist . field_bar)))
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;; (baz :initarg :baz :type integer :marshal ((alist . field_baz)))))
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;; (marshal-defclass plopi ()
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;; ((alpha :marshal ((alist . field_alpha)))
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;; (beta :type plop :marshal ((alist . field_beta)))))
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;; (marshal (make-instance 'plop :foo "ok" :bar 42) 'alist)
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;; => '((field_bar . 42) (field_foo . "ok"))
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;; (unmarshal 'plop '((field_foo . "plop") (field_bar . 0) (field_baz . 1)) 'alist)
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;; => '[object plop "plop" "plop" 0 1]
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;; (marshal
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;; (unmarshal 'plopi '((field_alpha . 42)
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;; (field_beta . ((field_foo . "plop")
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;; (field_bar . 0)
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;; (field_baz . 1)))) 'alist)
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;; 'alist)
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;; => '((field_beta (field_baz . 1) (field_bar . 0) (field_foo . "plop")) (field_alpha . 42))
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;; 2. Objects involving lists:
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;; (marshal-defclass foo/tree ()
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;; ((root :initarg :id :marshal ((plist . :root)))
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;; (leaves :initarg :leaves :marshal ((plist . :leaves)) :marshal-type (list foo/tree))))
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;; (marshal (make-instance 'foo/tree :id 0
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;; :leaves (list (make-instance 'foo/tree :id 1)
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;; (make-instance 'foo/tree :id 2
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;; :leaves (list (make-instance 'foo/tree :id 3)))))
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;; 'plist)
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;; => (:root 0 :leaves ((:root 1) (:root 2 :leaves ((:root 3)))))
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;; (unmarshal 'foo/tree '(:root 0 :leaves ((:root 1) (:root 2 :leaves ((:root 3))))) 'plist)
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;; => [object foo/tree "foo/tree" 0
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;; ([object foo/tree "foo/tree" 1 nil]
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;; [object foo/tree "foo/tree" 2
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;; ([object foo/tree "foo/tree" 3 nil])])]
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;; 3. Json
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;; (marshal (make-instance 'foo/tree :id 0
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;; :leaves (list (make-instance 'foo/tree :id 1)
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;; (make-instance 'foo/tree :id 2
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;; :leaves (list (make-instance 'foo/tree :id 3)))))
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;; 'json)
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;; => "{\"leaves\":[{\"root\":1},{\"leaves\":[{\"root\":3}],\"root\":2}],\"root\":0}"
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;; (unmarshal 'foo/tree "{\"leaves\":[{\"root\":1},{\"leaves\":[{\"root\":3}],\"root\":2}],\"root\":0}" 'json)
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;; => [object foo/tree "foo/tree" 0
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;; ([object foo/tree "foo/tree" 1 nil]
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;; [object foo/tree "foo/tree" 2
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;; ([object foo/tree "foo/tree" 3 nil])])]
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;;; Code:
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(require 'json)
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(require 'eieio)
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(require 'ht)
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;;; eieio backward-compatibility
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(dolist (sym '(object-class object-p oref oset))
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(let ((new-sym (intern (concat "eieio-" (symbol-name sym)))))
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(unless (fboundp new-sym)
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(fset new-sym sym))))
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;;; json hotfix
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(when (json-alist-p '(((foo))))
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(defun json-alist-p (list)
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(while (consp list)
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(setq list (if (and (consp (car list)) (atom (caar list)))
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(cdr list)
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'not-alist)))
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(null list)))
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;;; Defined drivers
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(defvar marshal-drivers nil "Alist of drivers")
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(defun marshal-register-driver (type driver)
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(add-to-list 'marshal-drivers (cons type driver)))
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;;; Marshalling driver interface
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(defclass marshal-driver ()
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((input :initarg :input)
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(output :initarg :output)))
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(defmethod marshal-open ((obj marshal-driver) &optional input)
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(if input
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(oset obj :input input)
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(oset obj :output nil)))
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(defmethod marshal-write ((obj marshal-driver) path value)
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(unless (slot-boundp obj :output)
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(error "Driver has not been opened in write mode")))
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(defmethod marshal-read ((obj marshal-driver) path)
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(unless (slot-boundp obj :input)
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(error "Driver has not been opened in read mode")))
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(defmethod marshal-close ((obj marshal-driver))
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(when (slot-boundp obj :output)
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(oref obj :output)))
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(defmethod marshal-guess-type :static ((obj marshal-driver) blob)
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(cond ((null blob) nil)
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((booleanp blob) 'bool)
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((stringp blob) 'string)
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((numberp blob) 'number)
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((listp blob) 'list)
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((ht? blob) 'hash)))
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(defmethod marshal-preprocess ((obj marshal-driver) blob)
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blob)
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(defmethod marshal-postprocess ((obj marshal-driver) blob)
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blob)
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(defmethod marshal-unmarshal-null :static ((obj marshal-driver))
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nil)
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(defmethod marshal-marshal-null :static ((obj marshal-driver))
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nil)
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(defmethod marshal-unmarshal-string :static ((obj marshal-driver) s)
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(format "%s" s))
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(defmethod marshal-marshal-string :static ((obj marshal-driver) s)
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s)
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(defmethod marshal-unmarshal-number :static ((obj marshal-driver) i)
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i)
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(defmethod marshal-marshal-number :static ((obj marshal-driver) i)
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i)
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(defmethod marshal-unmarshal-bool :static ((obj marshal-driver) b)
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(equal b t))
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(defmethod marshal-marshal-bool :static ((obj marshal-driver) b)
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(equal b t))
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(defmethod marshal-unmarshal-list :static ((obj marshal-driver) l l-type)
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(let ((type (or (and (object-p obj) (eieio-object-class obj))
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obj)))
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(cons (unmarshal-internal (when (consp l-type)
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(cadr l-type))
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(car l) type)
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(unmarshal-internal l-type (cdr l) type))))
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(defmethod marshal-marshal-list :static ((obj marshal-driver) l)
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(unless (null l)
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(let ((type (or (and (object-p obj) (eieio-object-class obj))
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obj)))
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(cons (marshal-internal (car l) type)
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(marshal-internal (cdr l) type)))))
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(defmethod marshal-unmarshal-hash :static ((obj marshal-driver) h h-type)
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(let ((type (or (and (object-p obj) (eieio-object-class obj))
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obj))
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(k-type (when (consp h-type) (nth 1 h-type)))
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(v-type (when (consp h-type) (nth 2 h-type))))
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(ht<-alist
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(mapcar (lambda (item)
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(cons (unmarshal-internal k-type (car item) type)
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(unmarshal-internal v-type (cdr item) type))) h))))
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(defmethod marshal-marshal-hash :static ((obj marshal-driver) h)
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(unless (ht-empty? h)
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(let ((type (or (and (object-p obj) (eieio-object-class obj))
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obj)))
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(mapcar (lambda (item)
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(cons (marshal-internal (car item) type)
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(marshal-internal (cadr item) type)))
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(ht-items h)))))
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;;; alist-based driver
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(defclass marshal-driver-alist (marshal-driver)
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())
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(defmethod marshal-write ((obj marshal-driver-alist) path value)
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(call-next-method)
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(object-add-to-list obj :output (cons path value)))
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(defmethod marshal-read ((obj marshal-driver-alist) path)
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(call-next-method)
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(cdr (assoc path (oref obj :input))))
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;;; json driver
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(defclass marshal-driver-json (marshal-driver-alist)
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())
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(defmethod marshal-preprocess ((obj marshal-driver-json) blob)
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(let ((json-array-type 'list)
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(json-object-type 'alist))
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(json-read-from-string (call-next-method))))
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(defmethod marshal-postprocess ((obj marshal-driver-json) blob)
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(json-encode (call-next-method)))
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(defmethod marshal-unmarshal-bool :static ((obj marshal-driver-json) b)
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(not (eq b json-false)))
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(defmethod marshal-marshal-bool :static ((obj marshal-driver-json) b)
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(or b json-false))
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;;; plist-based driver
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(defclass marshal-driver-plist (marshal-driver)
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())
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(defmethod marshal-write ((obj marshal-driver-plist) path value)
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(call-next-method)
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(oset obj :output (plist-put (oref obj :output) path value)))
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(defmethod marshal-read ((obj marshal-driver-plist) path)
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(call-next-method)
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(plist-get (oref obj :input) path))
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;;; helper functions
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(defun marshal--alist-add (alist key value &optional append)
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(let ((existing (assoc key alist)))
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(if (not existing)
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(cons (cons key value) alist)
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(setcdr existing (if append
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(append (cdr existing) value)
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value))
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alist)))
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(defun marshal--alist-merge (alist1 alist2 &optional append)
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(let ((res alist1))
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(if alist2
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(let* ((pair (car alist2))
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(x (car pair))
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(y (cdr pair)))
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(marshal--alist-merge
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(marshal--alist-add alist1 x y append)
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(cdr alist2)))
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alist1)))
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(defun marshal--transpose-alist2 (l)
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(let (res
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(rows l))
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(while rows
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(let* ((row (car rows))
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(x (car row))
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(cols (cdr row)))
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(while cols
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(let* ((col (car cols))
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(y (car col))
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(z (cdr col))
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(target (or (assoc y res)
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(let ((p (cons y nil)))
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(setq res (push p res))
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p))))
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(setcdr target (cons (cons x z) (cdr target))))
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(setq cols (cdr cols))))
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(setq rows (cdr rows)))
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res))
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;;; base-class for serializable objects
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(defclass marshal-base ()
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((-marshal-info :allocation :class :initform nil :protection :protected)
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(-type-info :allocation :class :initform nil :protection :protected)))
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(defmethod marshal-get-marshal-info :static ((obj marshal-base))
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nil)
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(defmethod marshal-get-type-info :static ((obj marshal-base))
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nil)
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(defun marshal-get-driver (type)
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(let ((cls (or (and (class-p type) type)
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(cdr (assoc type marshal-drivers))
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'marshal-driver)))
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(make-instance cls)))
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(defmethod marshal-internal ((obj marshal-base) type &optional hint)
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(let* ((type (or (and (class-p type)
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(car (rassoc type marshal-drivers)))
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type))
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(driver (marshal-get-driver type))
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(marshal-info (cdr (assoc type (marshal-get-marshal-info obj)))))
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(marshal-open driver)
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(when marshal-info
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(dolist (s (object-slots obj))
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(let ((path (cdr (assoc s marshal-info))))
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(when (and path
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(slot-boundp obj s))
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(marshal-write driver path
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(marshal-internal
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(eieio-oref obj s)
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type
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(cdr (assoc s (marshal-get-type-info obj)))))))))
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(marshal-close driver)))
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(defmethod marshal-internal ((obj nil) type &optional hint)
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(let ((driver (marshal-get-driver type)))
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(cond ((and (null hint) (null obj))
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(marshal-marshal-null driver))
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((or (eq obj t)
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(and (null obj) (eq hint 'bool)))
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(marshal-marshal-bool driver obj))
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((stringp obj)
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(marshal-marshal-string driver obj))
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((numberp obj)
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(marshal-marshal-number driver obj))
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((listp obj)
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(marshal-marshal-list driver obj))
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((ht? obj)
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(marshal-marshal-hash driver obj)))))
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;;;###autoload
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(defun marshal (obj type)
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(let ((driver (marshal-get-driver type)))
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(marshal-postprocess driver
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(marshal-internal obj type))))
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(defmethod unmarshal--obj ((obj marshal-base) blob type)
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(let ((driver (marshal-get-driver type))
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(marshal-info (cdr (assoc type (marshal-get-marshal-info obj)))))
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(marshal-open driver blob)
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(when (and marshal-info blob)
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(dolist (s (object-slots obj))
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(let ((path (cdr (assoc s marshal-info))))
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(when path
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(eieio-oset obj s
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(unmarshal-internal
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(cdr (assoc s (marshal-get-type-info obj)))
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(marshal-read driver path)
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type))))))
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(marshal-close driver)
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obj))
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(defun unmarshal-internal (obj blob type)
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(let ((obj (if (class-p obj)
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(make-instance obj)
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obj)))
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(unmarshal--internal obj blob type)))
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(defmethod unmarshal--internal ((obj nil) blob type)
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(let* ((driver (marshal-get-driver type))
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(obj (or obj (marshal-guess-type driver blob))))
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(cond ((or (null obj) (null blob))
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(marshal-unmarshal-null driver))
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((eq obj 'bool)
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(marshal-unmarshal-bool driver blob))
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((eq obj 'string)
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(marshal-unmarshal-string driver blob))
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((memq obj '(number integer))
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(marshal-unmarshal-number driver blob))
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((or (eq obj 'list)
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(and (consp obj) (eq (car obj) 'list)))
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(marshal-unmarshal-list driver blob obj))
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((or (eq obj 'hash)
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(and (consp obj) (eq (car obj) 'hash)))
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(marshal-unmarshal-hash driver blob obj)))))
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(defmethod unmarshal--internal ((obj marshal-base) blob type)
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(let ((type (or (and (class-p type)
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(car (rassoc type marshal-drivers)))
|
||
|
type)))
|
||
|
(unmarshal--obj obj blob type)))
|
||
|
|
||
|
;;;###autoload
|
||
|
(defun unmarshal (obj blob type)
|
||
|
(let ((driver (marshal-get-driver type)))
|
||
|
(unmarshal-internal obj (marshal-preprocess driver blob) type)))
|
||
|
|
||
|
;;;###autoload
|
||
|
(defmacro marshal-defclass (name superclass slots &rest options-and-doc)
|
||
|
(declare (debug t) (indent 2))
|
||
|
(let* ((options (if (stringp (car options-and-doc))
|
||
|
(cdr options-and-doc)
|
||
|
options-and-doc))
|
||
|
(default-spec-func (or (plist-get options :marshal-default-spec)
|
||
|
'ignore))
|
||
|
(base-cls (or (plist-get options :marshal-base-cls)
|
||
|
'marshal-base))
|
||
|
(marshal-info (marshal--transpose-alist2
|
||
|
(remove nil
|
||
|
(mapcar
|
||
|
(lambda (s)
|
||
|
(let ((name (car s)))
|
||
|
(let ((marshal
|
||
|
(or (plist-get (cdr s) :marshal)
|
||
|
(funcall default-spec-func name))))
|
||
|
(when marshal
|
||
|
(cons name
|
||
|
(mapcar
|
||
|
(lambda (p)
|
||
|
(if (consp p)
|
||
|
p
|
||
|
(cons p name)))
|
||
|
marshal))))))
|
||
|
slots))))
|
||
|
(type-info (remove nil
|
||
|
(mapcar (lambda (s)
|
||
|
(let ((name (car s)))
|
||
|
(let ((type (or (plist-get (cdr s) :marshal-type)
|
||
|
(plist-get (cdr s) :type))))
|
||
|
(when type
|
||
|
(cons name type)))))
|
||
|
slots))))
|
||
|
`(progn
|
||
|
(defclass ,name (,@superclass ,base-cls)
|
||
|
(,@slots)
|
||
|
,@options-and-doc)
|
||
|
|
||
|
(defmethod marshal-get-marshal-info :static ((obj ,name))
|
||
|
(let ((cls (if (eieio-object-p obj)
|
||
|
(eieio-object-class obj)
|
||
|
obj)))
|
||
|
(get cls :marshal-info)))
|
||
|
|
||
|
(put ',name :marshal-info ',marshal-info)
|
||
|
(dolist (cls ',superclass)
|
||
|
(put ',name :marshal-info
|
||
|
(marshal--alist-merge (get ',name :marshal-info)
|
||
|
(marshal-get-marshal-info cls) t)))
|
||
|
|
||
|
(defmethod marshal-get-type-info :static ((obj ,name))
|
||
|
(let ((cls (if (eieio-object-p obj)
|
||
|
(eieio-object-class obj)
|
||
|
obj)))
|
||
|
(get cls :type-info)))
|
||
|
|
||
|
(put ',name :type-info ',type-info)
|
||
|
(dolist (cls ',superclass)
|
||
|
(put ',name :type-info
|
||
|
(marshal--alist-merge (get ',name :type-info)
|
||
|
(marshal-get-type-info cls) t)))
|
||
|
|
||
|
,name)))
|
||
|
|
||
|
;;; Default drivers
|
||
|
(marshal-register-driver 'alist 'marshal-driver-alist)
|
||
|
(marshal-register-driver 'plist 'marshal-driver-plist)
|
||
|
(marshal-register-driver 'json 'marshal-driver-json)
|
||
|
|
||
|
(provide 'marshal)
|
||
|
;;; marshal.el ends here
|