You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
132 lines
5.2 KiB
Racket
132 lines
5.2 KiB
Racket
#lang restructure/racket
|
|
(require racket/dict "struct.rkt")
|
|
(provide (all-defined-out))
|
|
|
|
#|
|
|
approximates
|
|
https://github.com/mbutterick/restructure/blob/master/src/VersionedStruct.coffee
|
|
|#
|
|
|
|
(define-subclass Struct (VersionedStruct type [versions (dictify)])
|
|
|
|
(unless ((disjoin integer? procedure? RestructureBase? symbol?) type)
|
|
(raise-argument-error 'VersionedStruct "integer, function, symbol, or Restructure object" type))
|
|
(unless (and (dict? versions) (andmap (λ (val) (or (dict? val) (Struct? val))) (map cdr versions)))
|
|
(raise-argument-error 'VersionedStruct "dict of dicts or Structs" versions))
|
|
|
|
(inherit _setup _parseFields process)
|
|
(inherit-field fields)
|
|
(field [forced-version #f]
|
|
[versionGetter void]
|
|
[versionSetter void])
|
|
|
|
(when (symbol? type) ; instead of string
|
|
(set-field! versionGetter this (λ (parent) (ref parent type)))
|
|
(set-field! versionSetter this (λ (parent version) (ref-set! parent type version))))
|
|
|
|
(define/override (decode stream [parent #f] [length 0])
|
|
(define res (_setup stream parent length))
|
|
|
|
(ref-set! res 'version
|
|
(cond
|
|
[forced-version] ; for testing purposes: pass an explicit version
|
|
[(symbol? type) (unless parent
|
|
(raise-argument-error 'VersionedStruct:decode "valid parent" parent))
|
|
(versionGetter parent)]
|
|
[else (send type decode stream)]))
|
|
|
|
(when (dict-ref versions 'header #f)
|
|
(_parseFields stream res (ref versions 'header)))
|
|
|
|
(define fields (dict-ref versions (ref res 'version) (λ () (raise-argument-error 'VersionedStruct:decode "valid version key" (cons version (· this versions))))))
|
|
|
|
(cond
|
|
[(VersionedStruct? fields) (send fields decode stream parent)]
|
|
[else
|
|
(_parseFields stream res fields)
|
|
(process res stream)
|
|
res]))
|
|
|
|
(define/public-final (force-version! version)
|
|
(set! forced-version version))
|
|
|
|
(define/override (encode stream input-hash [parent #f])
|
|
(unless (hash? input-hash)
|
|
(raise-argument-error 'Struct:encode "hash" input-hash))
|
|
|
|
(send this preEncode input-hash stream) ; preEncode goes first, because it might bring input hash into compliance
|
|
|
|
(define fields (dict-ref versions (· input-hash version) (λ () (raise-argument-error 'VersionedStruct:encode "valid version key" version))))
|
|
|
|
(unless (andmap (λ (key) (member key (hash-keys input-hash))) (dict-keys fields))
|
|
(raise-argument-error 'Struct:encode (format "hash that contains superset of Struct keys: ~a" (dict-keys fields)) (hash-keys input-hash)))
|
|
|
|
(cond
|
|
[(dict? fields)
|
|
(for* ([(key type) (in-dict fields)])
|
|
(send type encode stream (hash-ref input-hash key)))]
|
|
[else (send fields encode stream input-hash parent)]))
|
|
|
|
|
|
(define/override (size [val (mhash)] [parent #f] [includePointers #t])
|
|
(unless (or val forced-version)
|
|
(error 'VersionedStruct-cannot-compute-size))
|
|
|
|
(define ctx (mhash 'parent parent
|
|
'val val
|
|
'pointerSize 0))
|
|
|
|
(define size 0)
|
|
(when (not (string? type))
|
|
(increment! size (send type size (ref val 'version) ctx)))
|
|
|
|
(when (ref versions 'header)
|
|
(increment! size
|
|
(for/sum ([(key type) (in-dict (ref versions 'header))])
|
|
(send type size (ref val key) ctx))))
|
|
|
|
(define fields (dict-ref versions (ref val 'version) (λ () (raise-argument-error 'VersionedStruct:encode "valid version key" version))))
|
|
|
|
(increment! size
|
|
(for/sum ([(key type) (in-dict (ref versions 'header))])
|
|
(send type size (ref val key) ctx)))
|
|
|
|
(when includePointers
|
|
(increment! size (ref ctx 'pointerSize)))
|
|
|
|
size))
|
|
|
|
#;(test-module
|
|
(require "number.rkt")
|
|
(define (random-pick xs) (list-ref xs (random (length xs))))
|
|
(check-exn exn:fail:contract? (λ () (+VersionedStruct 42 42)))
|
|
|
|
;; make random versioned structs and make sure we can round trip
|
|
(for ([i (in-range 20)])
|
|
(define field-types (for/list ([i (in-range 200)])
|
|
(random-pick (list uint8 uint16be uint16le uint32be uint32le double))))
|
|
(define num-versions 20)
|
|
(define which-struct (random num-versions))
|
|
(define struct-versions (for/list ([v (in-range num-versions)])
|
|
(cons v (for/list ([num-type (in-list field-types)])
|
|
(cons (gensym) num-type)))))
|
|
(define vs (+VersionedStruct which-struct struct-versions))
|
|
(define struct-size (for/sum ([num-type (in-list (map cdr (dict-ref struct-versions which-struct)))])
|
|
(send num-type size)))
|
|
(define bs (apply bytes (for/list ([i (in-range struct-size)])
|
|
(random 256))))
|
|
(check-equal? (send vs encode #f (send vs decode bs)) bs))
|
|
|
|
(define s (+Struct (dictify 'a uint8 'b uint8 'c uint8)))
|
|
(check-equal? (send s size) 3)
|
|
(define vs (+VersionedStruct (λ (p) 2) (dictify 1 (dictify 'd s) 2 (dictify 'e s 'f s))))
|
|
(check-equal? (send vs size) 6)
|
|
(define s2 (+Struct (dictify 'a vs)))
|
|
(check-equal? (send s2 size) 6)
|
|
(define vs2 (+VersionedStruct (λ (p) 2) (dictify 1 vs 2 vs)))
|
|
(check-equal? (send vs2 size) 6)
|
|
|
|
)
|
|
|
|
|