compatibility/collects/mzlib/foreign.ss
Eli Barzilay 9f077008d6 fix misuse of _
svn: r10569

original commit: ecfc0cd104265fadfe71ea05116aa29bccf90261
2008-07-03 00:49:52 +00:00

1558 lines
68 KiB
Scheme

#lang scheme/base
;; Foreign Scheme interface
(require '#%foreign
setup/dirs
(for-syntax scheme/base
syntax/stx))
;; This module is full of unsafe bindings that are not provided to requiring
;; modules. Instead, an `unsafe!' binding is provided that makes these unsafe
;; bindings available. The following two syntaxes do that: `provide*' is like
;; `provide', but using `(unsafe id)' registers an unsafe binding. Then,
;; `define-unsafer' should be used with a binding that will expose the unsafe
;; bindings. This might move elsewhere at some point if it turns out to be
;; useful in other contexts.
(provide provide* define-unsafer)
(define-syntaxes (provide* define-unsafer)
(let ((unsafe-bindings '()))
(values
(lambda (stx)
(syntax-case stx ()
[(_ p ...)
(let loop ([provides '()]
[unsafes '()]
[ps (syntax->list #'(p ...))])
(if (null? ps)
(begin (set! unsafe-bindings
(append unsafe-bindings (reverse unsafes)))
(with-syntax ([(p ...) provides]) #'(provide p ...)))
(syntax-case (car ps) (unsafe)
[(unsafe u)
(syntax-case #'u (rename-out)
[(rename-out [from to])
(loop provides (cons (cons #'from #'to) unsafes) (cdr ps))]
[id (identifier? #'id)
(loop provides (cons (cons #'id #'id) unsafes) (cdr ps))]
[_
(raise-syntax-error 'provide* "bad unsafe usage"
(car ps) stx)])]
[_ (loop (cons (car ps) provides) unsafes (cdr ps))])))]))
(lambda (stx)
(syntax-case stx ()
[(_ unsafe)
(with-syntax ([(from ...) (map car unsafe-bindings)]
[(to ...) (map cdr unsafe-bindings)]
[(id ...) (generate-temporaries unsafe-bindings)])
(set! unsafe-bindings '())
#'(begin
(provide (protect-out unsafe))
(define-syntax (unsafe stx)
(syntax-case stx ()
[(_) (with-syntax ([(id ...) (list (datum->syntax
stx 'to stx)
...)])
#'(begin (define-syntax id
(make-rename-transformer #'from))
...))]))))])))))
(provide* ctype-sizeof ctype-alignof compiler-sizeof
(unsafe malloc) (unsafe free) (unsafe end-stubborn-change)
cpointer? ptr-equal? ptr-add (unsafe ptr-ref) (unsafe ptr-set!)
ptr-offset ptr-add! offset-ptr? set-ptr-offset!
ctype? make-ctype make-cstruct-type (unsafe make-sized-byte-string)
_void _int8 _uint8 _int16 _uint16 _int32 _uint32 _int64 _uint64
_fixint _ufixint _fixnum _ufixnum
_float _double _double*
_bool _pointer _scheme _fpointer
(unsafe memcpy) (unsafe memmove) (unsafe memset)
(unsafe malloc-immobile-cell) (unsafe free-immobile-cell))
(define-syntax define*
(syntax-rules ()
[(_ (name . args) body ...)
(begin (provide name) (define (name . args) body ...))]
[(_ name expr)
(begin (provide name) (define name expr))]))
;; ----------------------------------------------------------------------------
;; C integer types
(define* _sint8 _int8)
(define* _sint16 _int16)
(define* _sint32 _int32)
(define* _sint64 _int64)
;; _byte etc is a convenient name for _uint8 & _sint8
;; (_byte is unsigned)
(define* _byte _uint8)
(define* _ubyte _uint8)
(define* _sbyte _int8)
;; _word etc is a convenient name for _uint16 & _sint16
;; (_word is unsigned)
(define* _word _uint16)
(define* _uword _uint16)
(define* _sword _int16)
;; _short etc is a convenient name for whatever is the compiler's `short'
;; (_short is signed)
(provide _short _ushort _sshort)
(define-values (_short _ushort _sshort)
(case (compiler-sizeof 'short)
[(2) (values _int16 _uint16 _int16)]
[(4) (values _int32 _uint32 _int32)]
[else (error 'foreign "internal error: bad compiler size for `short'")]))
;; _int etc is a convenient name for whatever is the compiler's `int'
;; (_int is signed)
(provide _int _uint _sint)
(define-values (_int _uint _sint)
(case (compiler-sizeof 'int)
[(2) (values _int16 _uint16 _int16)]
[(4) (values _int32 _uint32 _int32)]
[(8) (values _int64 _uint64 _int64)]
[else (error 'foreign "internal error: bad compiler size for `int'")]))
;; _long etc is a convenient name for whatever is the compiler's `long'
;; (_long is signed)
(provide _long _ulong _slong)
(define-values (_long _ulong _slong)
(case (compiler-sizeof 'long)
[(4) (values _int32 _uint32 _int32)]
[(8) (values _int64 _uint64 _int64)]
[else (error 'foreign "internal error: bad compiler size for `long'")]))
;; _llong etc is a convenient name for whatever is the compiler's `long long'
;; (_llong is signed)
(provide _llong _ullong _sllong)
(define-values (_llong _ullong _sllong)
(case (compiler-sizeof '(long long))
[(4) (values _int32 _uint32 _int32)]
[(8) (values _int64 _uint64 _int64)]
[else (error 'foreign "internal error: bad compiler size for `llong'")]))
;; ----------------------------------------------------------------------------
;; Getting and setting library objects
(define lib-suffix (bytes->string/latin-1 (subbytes (system-type 'so-suffix) 1)))
(define lib-suffix-re (regexp (string-append "\\." lib-suffix "$")))
(provide* (unsafe (rename-out [get-ffi-lib ffi-lib]))
ffi-lib? ffi-lib-name)
(define get-ffi-lib
(case-lambda
[(name) (get-ffi-lib name "")]
[(name version/s)
(cond
[(not name) (ffi-lib name)] ; #f => NULL => open this executable
[(not (or (string? name) (path? name)))
(raise-type-error 'ffi-lib "library-name" name)]
[else
;; A possible way that this might be misleading: say that there is a
;; "foo.so" file in the current directory, which refers to some
;; undefined symbol, trying to use this function with "foo.so" will try
;; a dlopen with "foo.so" which isn't found, then it tries a dlopen with
;; "/<curpath>/foo.so" which fails because of the undefined symbol, and
;; since all fails, it will use (ffi-lib "foo.so") to raise the original
;; file-not-found error. This is because the dlopen doesn't provide a
;; way to distinguish different errors (only dlerror, but that's
;; unreliable).
(let* ([versions (if (list? version/s) version/s (list version/s))]
[versions (map (lambda (v)
(if (or (not v) (zero? (string-length v)))
"" (string-append "." v)))
versions)]
[fullpath (lambda (p) (path->complete-path (cleanse-path p)))]
[absolute? (absolute-path? name)]
[name0 (path->string (cleanse-path name))] ; orig name
[names (map (if (regexp-match lib-suffix-re name0) ; name+suffix
(lambda (v) (string-append name0 v))
(lambda (v) (string-append name0 "." lib-suffix v)))
versions)]
[ffi-lib* (lambda (name) (ffi-lib name #t))])
(or ;; try to look in our library paths first
(and (not absolute?)
(ormap (lambda (dir)
;; try good names first, then original
(or (ormap (lambda (name)
(ffi-lib* (build-path dir name)))
names)
(ffi-lib* (build-path dir name0))))
(get-lib-search-dirs)))
;; try a system search
(ormap ffi-lib* names) ; try good names first
(ffi-lib* name0) ; try original
(ormap (lambda (name) ; try relative paths
(and (file-exists? name) (ffi-lib* (fullpath name))))
names)
(and (file-exists? name0) ; relative with original
(ffi-lib* (fullpath name0)))
;; give up: call ffi-lib so it will raise an error
(ffi-lib (car names))))])]))
(define (get-ffi-lib-internal x)
(if (ffi-lib? x) x (get-ffi-lib x)))
;; These internal functions provide the functionality to be used by
;; get-ffi-obj, set-ffi-obj! and define-c below
(define (ffi-get ffi-obj type)
(ptr-ref ffi-obj type))
(define (ffi-set! ffi-obj type new)
(let-values ([(new type) (get-lowlevel-object new type)])
(hash-set! ffi-objects-ref-table ffi-obj new)
(ptr-set! ffi-obj type new)))
;; This is better handled with `make-c-parameter'
(provide* (unsafe ffi-obj-ref))
(define ffi-obj-ref
(case-lambda
[(name lib) (ffi-obj-ref name lib #f)]
[(name lib failure)
(let ([name (get-ffi-obj-name 'ffi-obj-ref name)]
[lib (get-ffi-lib-internal lib)])
(with-handlers ([exn:fail:filesystem?
(lambda (e) (if failure (failure) (raise e)))])
(ffi-obj name lib)))]))
;; get-ffi-obj is implemented as a syntax only to be able to propagate the
;; foreign name into the type syntax, which allows generated wrappers to have a
;; proper name.
(provide* (unsafe get-ffi-obj))
(define get-ffi-obj*
(case-lambda
[(name lib type) (get-ffi-obj* name lib type #f)]
[(name lib type failure)
(let ([name (get-ffi-obj-name 'get-ffi-obj name)]
[lib (get-ffi-lib-internal lib)])
(let-values ([(obj error?)
(with-handlers
([exn:fail:filesystem?
(lambda (e)
(if failure (values (failure) #t) (raise e)))])
(values (ffi-obj name lib) #f))])
(if error? obj (ffi-get obj type))))]))
(define-syntax (get-ffi-obj stx)
(syntax-case stx ()
[(_ name lib type)
#`(get-ffi-obj* name lib #,(syntax-property #`type 'ffi-name #'name))]
[(_ name lib type failure)
#`(get-ffi-obj* name lib #,(syntax-property #`type 'ffi-name #'name)
failure)]
[x (identifier? #'x) #'get-ffi-obj*]))
;; It is important to use the set-ffi-obj! wrapper because it takes care of
;; keeping a handle on the object -- otherwise, setting a callback hook will
;; crash when the Scheme function is gone.
(provide* (unsafe set-ffi-obj!))
(define (set-ffi-obj! name lib type new)
(ffi-set! (ffi-obj (get-ffi-obj-name 'set-ffi-obj! name)
(get-ffi-lib-internal lib))
type new))
;; Combining the above two in a `define-c' special form which makes a Scheme
;; `binding', first a `parameter'-like constructor:
(provide* (unsafe make-c-parameter))
(define (make-c-parameter name lib type)
(let ([obj (ffi-obj (get-ffi-obj-name 'make-c-parameter name)
(get-ffi-lib-internal lib))])
(case-lambda [() (ffi-get obj type)]
[(new) (ffi-set! obj type new)])))
;; Then the fake binding syntax, uses the defined identifier to name the
;; object:
(provide* (unsafe define-c))
(define-syntax (define-c stx)
(syntax-case stx ()
[(_ var-name lib-name type-expr)
(with-syntax ([(p) (generate-temporaries (list #'var-name))])
(namespace-syntax-introduce
#'(begin (define p (make-c-parameter 'var-name lib-name type-expr))
(define-syntax var-name
(syntax-id-rules (set!)
[(set! var val) (p val)]
[(var . xs) ((p) . xs)]
[var (p)])))))]))
;; Used to convert strings and symbols to a byte-string that names an object
(define (get-ffi-obj-name who objname)
(cond [(bytes? objname) objname]
[(symbol? objname) (get-ffi-obj-name who (symbol->string objname))]
[(string? objname) (string->bytes/utf-8 objname)]
[else (raise-type-error who "object-name" objname)]))
;; This table keeps references to values that are set in foreign libraries, to
;; avoid them being GCed. See set-ffi-obj! above.
(define ffi-objects-ref-table (make-hasheq))
;; ----------------------------------------------------------------------------
;; Compile-time support for fun-expanders
(begin-for-syntax
;; The `_fun' macro tears its input apart and reassemble it using pieces from
;; custom function types (macros). This whole deal needs some work to make
;; it play nicely with code certificates, so Matthew wrote the following
;; code. The idea is to create a define-fun-syntax which makes the new
;; syntax transformer be an object that carries extra information, later used
;; by `expand-fun-syntax/fun'.
(define fun-cert-key (gensym))
;; bug in begin-for-syntax (PR7104), see below
(define foo!!! (make-parameter #f))
(define (expand-fun-syntax/normal fun-stx stx)
((foo!!!) fun-stx stx))
(define-values (make-fun-syntax fun-syntax?
fun-syntax-proc fun-syntax-certifier fun-syntax-name)
(let-values ([(desc make pred? get set!)
(make-struct-type
'fun-syntax #f 3 0 #f '() (current-inspector)
expand-fun-syntax/normal)])
(values make pred?
(make-struct-field-accessor get 0 'proc)
(make-struct-field-accessor get 1 'certifier)
(make-struct-field-accessor get 2 'name))))
;; This is used to expand a fun-syntax in a _fun type context.
(define (expand-fun-syntax/fun stx)
(let loop ([stx stx])
(define (do-expand id id?) ; id? == are we expanding an identifier?
(define v (syntax-local-value id (lambda () #f)))
(define set!-trans? (set!-transformer? v))
(define proc (if set!-trans? (set!-transformer-procedure v) v))
(if (and (fun-syntax? proc) (or (not id?) set!-trans?))
;; Do essentially the same thing that `local-expand' does.
;; First, create an "introducer" to mark introduced identifiers:
(let* ([introduce (make-syntax-introducer)]
[expanded
;; Re-introduce mark related to expansion of `_fun':
(syntax-local-introduce
;; Re-add mark specific to this expansion, cancelling
;; some marks applied before expanding (leaving only
;; introuced syntax marked)
(introduce
;; Actually expand:
((fun-syntax-proc proc)
;; Add mark specific to this expansion:
(introduce
;; Remove mark related to expansion of `_fun':
(syntax-local-introduce stx)))))])
;; Certify based on definition of expander, then loop
;; to continue expanding:
(loop ((fun-syntax-certifier proc)
expanded fun-cert-key introduce)))
stx))
(syntax-case stx ()
[(id . rest) (identifier? #'id) (do-expand #'id #f)]
[id (identifier? #'id) (do-expand #'id #t)]
[_else stx])))
;; Use module-or-top-identifier=? because we use keywords like `=' and want
;; to make it possible to play with it at the toplevel.
(define id=? module-or-top-identifier=?)
(define (split-by key args)
(let loop ([args args] [r (list '())])
(cond [(null? args) (reverse (map reverse r))]
[(eq? key (car args)) (loop (cdr args) (cons '() r))]
[else (loop (cdr args)
(cons (cons (car args) (car r))
(cdr r)))])))
(define (filtmap f l)
(let loop ([l l] [r '()])
(if (null? l)
(reverse r)
(let ([x (f (car l))]) (loop (cdr l) (if x (cons x r) r))))))
(define (add-renamer body from to)
(with-syntax ([body body] [from from] [to to])
#'(let-syntax ([to (syntax-id-rules ()
[(_?_ . _rest_) (from . _rest_)] [_?_ from])])
body)))
(define (custom-type->keys type err)
(define stops (map (lambda (s) (datum->syntax type s #f))
'(#%app #%top #%datum)))
;; Expand `type' using expand-fun-syntax/fun
(define orig (expand-fun-syntax/fun type))
(define (with-arg x)
(syntax-case* x (=>) id=?
[(id => body) (identifier? #'id)
;; Extract #'body from its context, use a key it needs certification:
(list (syntax-recertify #'id orig #f fun-cert-key)
(syntax-recertify #'body orig #f fun-cert-key))]
[_else x]))
(define (cert-id id)
(syntax-recertify id orig #f fun-cert-key))
(let ([keys '()])
(define (setkey! key val . id?)
(cond
[(assq key keys)
(err "bad expansion of custom type (two `~a:'s)" key type)]
[(and (pair? id?) (car id?) (not (identifier? val)))
(err "bad expansion of custom type (`~a:' expects an identifier)"
key type)]
[else (set! keys (cons (cons key val) keys))]))
(let loop ([t orig])
(define (next rest . args) (apply setkey! args) (loop rest))
(syntax-case* t (type: expr: bind: 1st-arg: prev-arg: pre: post:) id=?
[(type: t x ...) (next #'(x ...) 'type #'t)]
[(expr: e x ...) (next #'(x ...) 'expr #'e)]
[(bind: id x ...) (next #'(x ...) 'bind (cert-id #'id) #t)]
[(1st-arg: id x ...) (next #'(x ...) '1st (cert-id #'id) #t)]
[(prev-arg: id x ...) (next #'(x ...) 'prev (cert-id #'id) #t)]
;; in the following two cases pass along orig for recertifying
[(pre: p x ...) (next #'(x ...) 'pre (with-arg #'p))]
[(post: p x ...) (next #'(x ...) 'post (with-arg #'p))]
[() (and (pair? keys) keys)]
[_else #f]))))
;; This is used for a normal expansion of fun-syntax, when not in a _fun type
;; context.
;; bug in begin-for-syntax (PR7104), see above
;; should be (define (expand-fun-syntax/normal fun-stx stx) ...)
(foo!!! (lambda (fun-stx stx)
(define (err msg . sub)
(apply raise-syntax-error (fun-syntax-name fun-stx) msg stx sub))
(let ([keys (custom-type->keys stx err)])
(define (getkey key) (cond [(assq key keys) => cdr] [else #f]))
(define (notkey key)
(when (getkey key)
(err (format "this type must be used in a _fun expression (uses ~s)"
key))))
(if keys
(let ([type (getkey 'type)] [pre (getkey 'pre)] [post (getkey 'post)])
(unless type
(err "this type must be used in a _fun expression (#f type)"))
(for-each notkey '(expr bind 1st prev))
(if (or pre post)
;; a type with pre/post blocks
(let ([make-> (lambda (x what)
(cond [(not x) #'#f]
[(and (list? x) (= 2 (length x))
(identifier? (car x)))
#`(lambda (#,(car x)) #,(cadr x))]
[else #`(lambda (_)
(error '#,(fun-syntax-name fun-stx)
"cannot be used to ~a"
#,what))]))])
(with-syntax ([type type]
[scheme->c (make-> pre "send values to C")]
[c->scheme (make-> post "get values from C")])
#'(make-ctype type scheme->c c->scheme)))
;; simple type
type))
;; no keys => normal expansion
((fun-syntax-proc fun-stx) stx))))))
;; Use define-fun-syntax instead of define-syntax for forms that
;; are to be expanded by `_fun':
(provide define-fun-syntax)
(define-syntax define-fun-syntax
(syntax-rules ()
[(_ id trans)
(define-syntax id
(let* ([xformer trans]
[set!-trans? (set!-transformer? xformer)])
(unless (or (and (procedure? xformer)
(procedure-arity-includes? xformer 1))
set!-trans?)
(raise-type-error 'define-fun-syntax
"procedure (arity 1) or set!-transformer"
xformer))
(let ([f (make-fun-syntax (if set!-trans?
(set!-transformer-procedure xformer)
xformer)
;; Capture definition-time certificates:
(syntax-local-certifier)
'id)])
(if set!-trans? (make-set!-transformer f) f))))]))
;; ----------------------------------------------------------------------------
;; Function type
;; Creates a simple function type that can be used for callouts and callbacks,
;; optionally applying a wrapper function to modify the result primitive
;; (callouts) or the input procedure (callbacks).
(define* (_cprocedure itypes otype . wrapper)
(let ([wrapper (and (pair? wrapper) (car wrapper))])
(if wrapper
(make-ctype _fpointer
(lambda (x) (ffi-callback (wrapper x) itypes otype))
(lambda (x) (wrapper (ffi-call x itypes otype))))
(make-ctype _fpointer
(lambda (x) (ffi-callback x itypes otype))
(lambda (x) (ffi-call x itypes otype))))))
;; Syntax for the special _fun type:
;; (_fun [{(name ... [. name]) | name} [-> expr] ::]
;; {type | (name : type [= expr]) | ([name :] type = expr)} ...
;; -> {type | (name : type)}
;; [-> expr])
;; Usage:
;; `{(name ...) | ...} ::' specify explicit wrapper function formal arguments
;; `-> expr' can be used instead of the last expr
;; `type' input type (implies input, but see type macros next)
;; `(name : type = expr)' specify name and type, `= expr' means computed input
;; `-> type' output type (possibly with name)
;; `-> expr' specify different output, can use previous names
;; Also, see below for custom function types.
(provide ->) ; to signal better errors when trying to use this with contracts
(define-syntax ->
(syntax-id-rules ()
[_ (raise-syntax-error '-> "should be used only in a _fun context")]))
(provide _fun)
(define-syntax (_fun stx)
(define (err msg . sub) (apply raise-syntax-error '_fun msg stx sub))
(syntax-case stx ()
[(_ x ...)
(let ([xs (map (lambda (x)
(syntax-case* x (-> ::) id=? [:: '::] [-> '->] [_ x]))
(syntax->list #'(x ...)))]
[inputs #f] [output #f] [bind '()] [pre '()] [post '()]
[input-names #f] [output-type #f] [output-expr #f]
[1st-arg #f] [prev-arg #f])
(define (bind! x) (set! bind (append bind (list x))))
(define (pre! x) (set! pre (append pre (list x))))
(define (post! x) (set! post (append post (list x))))
(define ((t-n-e clause) type name expr)
(let ([keys (custom-type->keys type err)])
(define (getkey key) (cond [(assq key keys) => cdr] [else #f]))
(define (arg x . no-expr?)
(define use-expr?
(and (list? x) (= 2 (length x)) (identifier? (car x))))
;; when the current expr is not used with a (x => ...) form,
;; either check that no expression is given or just make it
;; disappear from the inputs.
(unless use-expr?
(if (and (pair? no-expr?) (car no-expr?) expr)
(err "got an expression for a custom type that do not use it"
clause)
(set! expr (void))))
(set! x (if use-expr? (add-renamer (cadr x) name (car x)) x))
(cond [(getkey '1st) =>
(lambda (v)
(if 1st-arg
(set! x (add-renamer x 1st-arg v))
(err "got a custom type that wants 1st arg too early"
clause)))])
(cond [(getkey 'prev) =>
(lambda (v)
(if prev-arg
(set! x (add-renamer x prev-arg v))
(err "got a custom type that wants prev arg too early"
clause)))])
x)
(when keys
(set! type (getkey 'type))
(cond [(and (not expr) (getkey 'expr)) =>
(lambda (x) (set! expr x))])
(cond [(getkey 'bind) =>
(lambda (x) (bind! #`[#,x #,name]))])
(cond [(getkey 'pre) =>
(lambda (x) (pre! #`[#,name #,(arg x #t)]))])
(cond [(getkey 'post) =>
(lambda (x) (post! #`[#,name #,(arg x)]))]))
;; turn a #f syntax to #f
(set! type (and type (syntax-case type () [#f #f] [_ type])))
(when type ; remember these for later usages
(unless 1st-arg (set! 1st-arg name))
(set! prev-arg name))
(list type name expr)))
;; parse "::"
(let ([s (split-by ':: xs)])
(case (length s)
[(0) (err "something bad happened (::)")]
[(1) #f]
[(2) (if (and (= 1 (length (car s))) (not (eq? '-> (caar s))))
(begin (set! xs (cadr s)) (set! input-names (caar s)))
(err "bad wrapper formals"))]
[else (err "saw two or more instances of `::'")]))
;; parse "->"
(let ([s (split-by '-> xs)])
(case (length s)
[(0) (err "something bad happened (->)")]
[(1) (err "missing output type")]
[(2 3) (set! inputs (car s))
(case (length (cadr s))
[(1) (set! output-type (caadr s))]
[(0) (err "missing output type after `->'")]
[else (err "extraneous output type" (cadadr s))])
(unless (null? (cddr s))
(case (length (caddr s))
[(1) (set! output-expr (caaddr s))]
[(0) (err "missing output expression after `->'")]
[else (err "extraneous output expression"
(cadr (caddr s)))]))]
[else (err "saw three or more instances of `->'")]))
(set! inputs
(map (lambda (sub temp)
(let ([t-n-e (t-n-e sub)])
(syntax-case* sub (: =) id=?
[(name : type) (t-n-e #'type #'name #f)]
[(type = expr) (t-n-e #'type temp #'expr)]
[(name : type = expr) (t-n-e #'type #'name #'expr)]
[type (t-n-e #'type temp #f)])))
inputs
(generate-temporaries (map (lambda (x) 'tmp) inputs))))
;; when processing the output type, only the post code matters
(set! pre! (lambda (x) #f))
(set! output
(let ([temp (car (generate-temporaries #'(ret)))]
[t-n-e (t-n-e output-type)])
(syntax-case* output-type (: =) id=?
[(name : type) (t-n-e #'type #'name output-expr)]
[(type = expr) (if output-expr
(err "extraneous output expression" #'expr)
(t-n-e #'type temp #'expr))]
[(name : type = expr)
(if output-expr
(err "extraneous output expression" #'expr)
(t-n-e #'type #'name #'expr))]
[type (t-n-e #'type temp output-expr)])))
(if (or (caddr output) input-names (ormap caddr inputs)
(ormap (lambda (x) (not (car x))) inputs)
(pair? bind) (pair? pre) (pair? post))
(let* ([input-names (or input-names
(filtmap (lambda (i)
(and (not (caddr i)) (cadr i)))
inputs))]
[output-expr (let ([o (caddr output)])
(or (and (not (void? o)) o)
(cadr output)))]
[args (filtmap (lambda (i) (and (caddr i)
(not (void? (caddr i)))
#`[#,(cadr i) #,(caddr i)]))
inputs)]
[ffi-args (filtmap (lambda (x) (and (car x) (cadr x)))
inputs)]
;; the actual wrapper body
[body (quasisyntax/loc stx
(lambda #,input-names
(let* (#,@args
#,@bind
#,@pre
[#,(cadr output) (ffi #,@ffi-args)]
#,@post)
#,output-expr)))]
;; if there is a string 'ffi-name property, use it as a name
[body (let ([n (cond [(syntax-property stx 'ffi-name)
=> syntax->datum]
[else #f])])
(if (string? n)
(syntax-property
body 'inferred-name
(string->symbol (string-append "ffi-wrapper:" n)))
body))])
#`(_cprocedure (list #,@(filtmap car inputs)) #,(car output)
(lambda (ffi) #,body)))
#`(_cprocedure (list #,@(filtmap car inputs)) #,(car output))))]))
;; ----------------------------------------------------------------------------
;; String types
;; The internal _string type uses the native ucs-4 encoding, also providing a
;; utf-16 type (note: these do not use #f as NULL).
(provide _string/ucs-4 _string/utf-16)
;; 8-bit string encodings, #f is NULL
(define ((false-or-op op) x) (and x (op x)))
(define* _string/utf-8
(make-ctype _bytes
(false-or-op string->bytes/utf-8) (false-or-op bytes->string/utf-8)))
(define* _string/locale
(make-ctype _bytes
(false-or-op string->bytes/locale) (false-or-op bytes->string/locale)))
(define* _string/latin-1
(make-ctype _bytes
(false-or-op string->bytes/latin-1) (false-or-op bytes->string/latin-1)))
;; 8-bit string encodings, #f is NULL, can also use bytes and paths
(define ((any-string-op op) x)
(cond [(not x) x]
[(bytes? x) x]
[(path? x) (path->bytes x)]
[else (op x)]))
(define* _string*/utf-8
(make-ctype _bytes
(any-string-op string->bytes/utf-8) (false-or-op bytes->string/utf-8)))
(define* _string*/locale
(make-ctype _bytes
(any-string-op string->bytes/locale) (false-or-op bytes->string/locale)))
(define* _string*/latin-1
(make-ctype _bytes
(any-string-op string->bytes/latin-1) (false-or-op bytes->string/latin-1)))
;; A generic _string type that usually does the right thing via a parameter
(define* default-_string-type
(make-parameter _string*/utf-8
(lambda (x)
(if (ctype? x)
x (error 'default-_string-type "expecting a C type, got ~e" x)))))
;; The type looks like an identifier, but it's actually using the parameter
(provide _string)
(define-syntax _string
(syntax-id-rules ()
[(_ . xs) ((default-_string-type) . xs)]
[_ (default-_string-type)]))
;; _symbol is defined in C, since it uses simple C strings
(provide _symbol)
(provide _path)
;; `file' type: path-expands a path string, provide _path too.
(define* _file (make-ctype _path cleanse-path #f))
;; `string/eof' type: converts an output #f (NULL) to an eof-object.
(define string-type->string/eof-type
(let ([table (make-hasheq)])
(lambda (string-type)
(hash-ref table string-type
(lambda ()
(let ([new-type (make-ctype string-type
(lambda (x) (and (not (eof-object? x)) x))
(lambda (x) (or x eof)))])
(hash-set! table string-type new-type)
new-type))))))
(provide _string/eof _bytes/eof)
(define _bytes/eof
(make-ctype _bytes
(lambda (x) (and (not (eof-object? x)) x))
(lambda (x) (or x eof))))
(define-syntax _string/eof ; make it a syntax so it depends on the _string type
(syntax-id-rules ()
[(_ . xs) ((string-type->string/eof-type _string) . xs)]
[_ (string-type->string/eof-type _string)]))
;; ----------------------------------------------------------------------------
;; Utility types
;; Call this with a name (symbol) and a list of symbols, where a symbol can be
;; followed by a '= and an integer to have a similar effect of C's enum.
(define (_enum* name symbols . base?)
(define basetype (if (pair? base?) (car base?) _ufixint))
(define sym->int '())
(define int->sym '())
(define s->c
(if name (string->symbol (format "enum:~a->int" name)) 'enum->int))
(let loop ([i 0] [symbols symbols])
(unless (null? symbols)
(let-values ([(i rest)
(if (and (pair? (cdr symbols))
(eq? '= (cadr symbols))
(pair? (cddr symbols)))
(values (caddr symbols)
(cdddr symbols))
(values i
(cdr symbols)))])
(set! sym->int (cons (cons (car symbols) i) sym->int))
(set! int->sym (cons (cons i (car symbols)) int->sym))
(loop (add1 i) rest))))
(make-ctype basetype
(lambda (x)
(let ([a (assq x sym->int)])
(if a
(cdr a)
(raise-type-error s->c (format "~a" (or name "enum")) x))))
(lambda (x) (cond [(assq x int->sym) => cdr] [else #f]))))
;; Macro wrapper -- no need for a name
(provide _enum)
(define-syntax (_enum stx)
(syntax-case stx ()
[(_ syms)
(with-syntax ([name (syntax-local-name)])
#'(_enum* 'name syms))]
[(_ syms basetype)
(with-syntax ([name (syntax-local-name)])
#'(_enum* 'name syms basetype))]
[id (identifier? #'id)
#'(lambda (syms . base?) (apply _enum* #f syms base?))]))
;; Call this with a name (symbol) and a list of (symbol int) or symbols like
;; the above with '= -- but the numbers have to be specified in some way. The
;; generated type will convert a list of these symbols into the logical-or of
;; their values and back.
(define (_bitmask* name orig-symbols->integers . base?)
(define basetype (if (pair? base?) (car base?) _uint))
(define s->c
(if name (string->symbol (format "bitmask:~a->int" name)) 'bitmask->int))
(define symbols->integers
(let loop ([s->i orig-symbols->integers])
(cond
[(null? s->i)
null]
[(and (pair? (cdr s->i)) (eq? '= (cadr s->i)) (pair? (cddr s->i)))
(cons (list (car s->i) (caddr s->i))
(loop (cdddr s->i)))]
[(and (pair? (car s->i)) (pair? (cdar s->i)) (null? (cddar s->i))
(symbol? (caar s->i)) (integer? (cadar s->i)))
(cons (car s->i) (loop (cdr s->i)))]
[else
(error '_bitmask "bad spec in ~e" orig-symbols->integers)])))
(make-ctype basetype
(lambda (symbols)
(if (null? symbols) ; probably common
0
(let loop ([xs (if (pair? symbols) symbols (list symbols))] [n 0])
(cond [(null? xs) n]
[(assq (car xs) symbols->integers) =>
(lambda (x) (loop (cdr xs) (bitwise-ior (cadr x) n)))]
[else (raise-type-error s->c (format "~a" (or name "bitmask"))
symbols)]))))
(lambda (n)
(if (zero? n) ; probably common
'()
(let loop ([s->i symbols->integers] [l '()])
(if (null? s->i)
(reverse l)
(loop (cdr s->i)
(let ([i (cadar s->i)])
(if (and (not (= i 0)) (= i (bitwise-and i n)))
(cons (caar s->i) l)
l)))))))))
;; Macro wrapper -- no need for a name
(provide _bitmask)
(define-syntax (_bitmask stx)
(syntax-case stx ()
[(_ syms)
(with-syntax ([name (syntax-local-name)])
#'(_bitmask* 'name syms))]
[(_ syms basetype)
(with-syntax ([name (syntax-local-name)])
#'(_bitmask* 'name syms basetype))]
[id (identifier? #'id)
#'(lambda (syms . base?) (apply _bitmask* #f syms base?))]))
;; ----------------------------------------------------------------------------
;; Custom function type macros
;; These macros get expanded by the _fun type. They can expand to a form that
;; looks like (keyword: value ...), where the keyword is one of:
;; * `type:' for the type that will be used,
;; * `expr:' an expression that will always be used for these arguments, as
;; if `= expr' is always given, when an expression is actually
;; given in an argument specification, it supersedes this.
;; * `bind:' for an additional binding that holds the initial value,
;; * `1st-arg:' is used to name an identifier that will be bound to the value
;; of the 1st foreign argument in pre/post chunks (good for
;; common cases where the first argument has a special meaning,
;; eg, for method calls),
;; * `prev-arg:' similar to 1st-arg: but for the previous argument,
;; * `pre:' for a binding that will be inserted before the ffi call,
;; * `post:' for a binding after the ffi call.
;; The pre: and post: bindings can be of the form (id => expr) to use the
;; existing value. Note that if the pre: expression is not (id => expr), then
;; it means that there is no input for this argument. Also note that if a
;; custom type is used as an output type of a function, then only the post:
;; code is used -- for example, this is useful for foreign functions that
;; allocate a memory block and return it to the user. The resulting wrapper
;; looks like:
;; (let* (...bindings for arguments...
;; ...bindings for bind: identifiers...
;; ...bindings for pre-code...
;; (ret-name ffi-call)
;; ...bindings for post-code...)
;; return-expression)
;;
;; Finally, the code in a custom-function macro needs special treatment when it
;; comes to dealing with code certificates, so instead of using
;; `define-syntax', you should use `define-fun-syntax' (used in the same way).
;; _?
;; This is not a normal ffi type -- it is a marker for expressions that should
;; not be sent to the ffi function. Use this to bind local values in a
;; computation that is part of an ffi wrapper interface.
(provide _?)
(define-fun-syntax _?
(syntax-id-rules () [(_ . xs) ((type: #f) . xs)] [_ (type: #f)]))
;; (_ptr <mode> <type>)
;; This is for pointers, where mode indicates input or output pointers (or
;; both). If the mode is `o' (output), then the wrapper will not get an
;; argument for it, instead it generates the matching argument.
(provide _ptr)
(define-fun-syntax _ptr
(syntax-rules (i o io)
[(_ i t) (type: _pointer
pre: (x => (let ([p (malloc t)]) (ptr-set! p t x) p)))]
[(_ o t) (type: _pointer
pre: (malloc t)
post: (x => (ptr-ref x t)))]
[(_ io t) (type: _pointer
pre: (x => (let ([p (malloc t)]) (ptr-set! p t x) p))
post: (x => (ptr-ref x t)))]))
;; (_box <type>)
;; This is similar to a (_ptr io <type>) argument, where the input is expected
;; to be a box, which is unboxed on entry and modified on exit.
(provide _box)
(define-fun-syntax _box
(syntax-rules ()
[(_ t) (type: _pointer
bind: tmp ; need to save the box so we can get back to it
pre: (x => (let ([p (malloc t)]) (ptr-set! p t (unbox x)) p))
post: (x => (begin (set-box! tmp (ptr-ref x t)) tmp)))]))
;; (_list <mode> <type> [<len>])
;; Similar to _ptr, except that it is used for converting lists to/from C
;; vectors. The length is needed for output values where it is used in the
;; post code, and in the pre code of an output mode to allocate the block. In
;; any case it can refer to a previous binding for the length of the list which
;; the C function will most likely require.
(provide _list)
(define-fun-syntax _list
(syntax-rules (i o io)
[(_ i t ) (type: _pointer
pre: (x => (list->cblock x t)))]
[(_ o t n) (type: _pointer
pre: (malloc n t)
post: (x => (cblock->list x t n)))]
[(_ io t n) (type: _pointer
pre: (x => (list->cblock x t))
post: (x => (cblock->list x t n)))]))
;; (_vector <mode> <type> [<len>])
;; Same as _list, except that it uses Scheme vectors.
(provide _vector)
(define-fun-syntax _vector
(syntax-rules (i o io)
[(_ i t ) (type: _pointer
pre: (x => (vector->cblock x t)))]
[(_ o t n) (type: _pointer
pre: (malloc n t)
post: (x => (cblock->vector x t n)))]
[(_ io t n) (type: _pointer
pre: (x => (vector->cblock x t))
post: (x => (cblock->vector x t n)))]))
;; _bytes or (_bytes o n) is for a memory block represented as a Scheme byte
;; string. _bytes is just like a byte-string, and (_bytes o n) is for
;; pre-malloc of the string. There is no need for other modes: i or io would
;; be just like _bytes since the string carries its size information (so there
;; is no real need for the `o', but it's there for consistency with the above
;; macros).
(provide (rename-out [_bytes* _bytes]))
(define-fun-syntax _bytes*
(syntax-id-rules (o)
[(_ o n) (type: _bytes
pre: (make-sized-byte-string (malloc n) n)
;; post is needed when this is used as a function output type
post: (x => (make-sized-byte-string x n)))]
[(_ . xs) (_bytes . xs)]
[_ _bytes]))
;; ----------------------------------------------------------------------------
;; Safe raw vectors
(define-struct cvector (ptr type length))
(provide* cvector? cvector-length cvector-type
;; make-cvector* is a dangerous operation
(unsafe (rename-out [make-cvector make-cvector*])))
(define _cvector* ; used only as input types
(make-ctype _pointer cvector-ptr
(lambda (x)
(error '_cvector
"cannot automatically convert a C pointer to a cvector"))))
;; (_cvector <mode> [<type> <len>]) | _cevector
;; Same as _list etc above, except that it uses C vectors.
(provide _cvector)
(define-fun-syntax _cvector
(syntax-id-rules (i o io)
[(_ i ) _cvector*]
[(_ o t n) (type: _pointer ; needs to be a pointer, not a cvector*
pre: (malloc n t)
post: (x => (make-cvector x t n)))]
[(_ io ) (type: _cvector*
bind: tmp
pre: (x => (cvector-ptr x))
post: (x => tmp))]
[(_ . xs) (_cvector* . xs)]
[_ _cvector*]))
(provide (rename-out [allocate-cvector make-cvector]))
(define (allocate-cvector type len)
(make-cvector (if (zero? len) #f ; 0 => NULL
(malloc len type))
type len))
(provide (rename-out [cvector-args cvector]))
(define (cvector-args type . args)
(list->cvector args type))
(define* (cvector-ref v i)
(if (and (integer? i) (<= 0 i (sub1 (cvector-length v))))
(ptr-ref (cvector-ptr v) (cvector-type v) i)
(error 'cvector-ref "bad index ~e for cvector bounds of 0..~e"
i (sub1 (cvector-length v)))))
(define* (cvector-set! v i x)
(if (and (integer? i) (<= 0 i (sub1 (cvector-length v))))
(ptr-set! (cvector-ptr v) (cvector-type v) i x)
(error 'cvector-ref "bad index ~e for cvector bounds of 0..~e"
i (sub1 (cvector-length v)))))
(define* (cvector->list v)
(cblock->list (cvector-ptr v) (cvector-type v) (cvector-length v)))
(define* (list->cvector l type)
(make-cvector (list->cblock l type) type (length l)))
;; ----------------------------------------------------------------------------
;; SRFI-4 implementation
(define-syntax (srfi-4-define/provide stx)
(syntax-case stx ()
[(_ TAG type)
(identifier? #'TAG)
(let ([name (format "~avector" (syntax->datum #'TAG))])
(define (id prefix suffix)
(let* ([name (if prefix (string-append prefix name) name)]
[name (if suffix (string-append name suffix) name)])
(datum->syntax #'TAG (string->symbol name) #'TAG)))
(with-syntax ([TAG? (id "" "?")]
[TAG (id "" "")]
[s:TAG (id "s:" "")]
[make-TAG (id "make-" "")]
[TAG-ptr (id "" "-ptr")]
[TAG-length (id "" "-length")]
[allocate-TAG (id "allocate-" "")]
[TAG* (id "" "*")]
[list->TAG (id "list->" "")]
[TAG->list (id "" "->list")]
[TAG-ref (id "" "-ref")]
[TAG-set! (id "" "-set!")]
[_TAG (id "_" "")]
[_TAG* (id "_" "*")]
[TAGname name])
#'(begin
(define-struct TAG (ptr length))
(provide TAG? TAG-length (rename-out [TAG s:TAG]))
(provide (rename-out [allocate-TAG make-TAG]))
(define (allocate-TAG n . init)
(let* ([p (if (eq? n 0) #f (malloc n type))]
[v (make-TAG p n)])
(when (and p (pair? init))
(let ([init (car init)])
(let loop ([i (sub1 n)])
(unless (< i 0)
(ptr-set! p type i init)
(loop (sub1 i))))))
v))
(provide (rename-out [TAG* TAG]))
(define (TAG* . vals)
(list->TAG vals))
(define* (TAG-ref v i)
(if (TAG? v)
(if (and (integer? i) (< -1 i (TAG-length v)))
(ptr-ref (TAG-ptr v) type i)
(error 'TAG-ref "bad index ~e for ~a bounds of 0..~e"
i 'TAG (sub1 (TAG-length v))))
(raise-type-error 'TAG-ref TAGname v)))
(define* (TAG-set! v i x)
(if (TAG? v)
(if (and (integer? i) (< -1 i (TAG-length v)))
(ptr-set! (TAG-ptr v) type i x)
(error 'TAG-set! "bad index ~e for ~a bounds of 0..~e"
i 'TAG (sub1 (TAG-length v))))
(raise-type-error 'TAG-set! TAGname v)))
(define* (TAG->list v)
(if (TAG? v)
(cblock->list (TAG-ptr v) type (TAG-length v))
(raise-type-error 'TAG->list TAGname v)))
(define* (list->TAG l)
(make-TAG (list->cblock l type) (length l)))
;; same as the _cvector implementation
(provide _TAG)
(define _TAG*
(make-ctype _pointer TAG-ptr
(lambda (x)
(error
'_TAG
"cannot automatically convert a C pointer to a ~a"
TAGname))))
(define-fun-syntax _TAG
(syntax-id-rules (i o io)
[(_ i ) _TAG*]
[(_ o n) (type: _pointer
pre: (malloc n type)
post: (x => (make-TAG x n)))]
[(_ io ) (type: _cvector*
bind: tmp
pre: (x => (TAG-ptr x))
post: (x => tmp))]
[(_ . xs) (_TAG* . xs)]
[_ _TAG*])))))]
[(_ TAG type)
(identifier? #'TAG)]))
;; check that the types that were used above have the proper sizes
(unless (= 4 (ctype-sizeof _float))
(error 'foreign "internal error: float has a bad size (~s)"
(ctype-sizeof _float)))
(unless (= 8 (ctype-sizeof _double*))
(error 'foreign "internal error: double has a bad size (~s)"
(ctype-sizeof _double*)))
(srfi-4-define/provide s8 _int8)
(srfi-4-define/provide s16 _int16)
(srfi-4-define/provide u16 _uint16)
(srfi-4-define/provide s32 _int32)
(srfi-4-define/provide u32 _uint32)
(srfi-4-define/provide s64 _int64)
(srfi-4-define/provide u64 _uint64)
(srfi-4-define/provide f32 _float)
(srfi-4-define/provide f64 _double*)
;; simply rename bytes* to implement the u8vector type
(provide (rename-out [bytes? u8vector? ]
[bytes-length u8vector-length]
[make-bytes make-u8vector ]
[bytes u8vector ]
[bytes-ref u8vector-ref ]
[bytes-set! u8vector-set! ]
[bytes->list u8vector->list ]
[list->bytes list->u8vector ]
[_bytes _u8vector ]))
;; additional `u8vector' bindings for srfi-66
(provide (rename-out [bytes-copy u8vector-copy] [bytes=? u8vector=?]))
(define* (u8vector-compare v1 v2)
(cond [(bytes<? v1 v2) -1]
[(bytes>? v1 v2) 1]
[else 0]))
(define* (u8vector-copy! src src-start dest dest-start n)
(bytes-copy! dest dest-start src src-start (+ src-start n)))
;; ----------------------------------------------------------------------------
;; Tagged pointers
;; Make these operations available for unsafe interfaces (they can be used to
;; grab a hidden tag value and break code).
(provide* (unsafe cpointer-tag) (unsafe set-cpointer-tag!)
(unsafe cpointer-has-tag?) (unsafe cpointer-push-tag!))
;; Defined as syntax for efficiency, but can be used as procedures too.
(define-syntax (cpointer-has-tag? stx)
(syntax-case stx ()
[(_ cptr tag)
#'(let ([ptag (cpointer-tag cptr)])
(if (pair? ptag) (memq tag ptag) (eq? tag ptag)))]
[id (identifier? #'id)
#'(lambda (cptr tag) (cpointer-has-tag? cptr tag))]))
(define-syntax (cpointer-push-tag! stx)
(syntax-case stx ()
[(_ cptr tag)
#'(let ([ptag (cpointer-tag cptr)])
(set-cpointer-tag! cptr
(cond [(not ptag) tag]
[(pair? ptag) (cons tag ptag)]
[else (list tag ptag)])))]
[id (identifier? #'id)
#'(lambda (cptr tag) (cpointer-push-tag! cptr tag))]))
(define (cpointer-maker nullable?)
(case-lambda
[(tag) ((cpointer-maker nullable?) tag #f #f #f)]
[(tag ptr-type) ((cpointer-maker nullable?) tag ptr-type #f #f)]
[(tag ptr-type scheme->c c->scheme)
(let* ([tag->C (string->symbol (format "~a->C" tag))]
[error-str (format "~a`~a' pointer"
(if nullable? "" "non-null ") tag)]
[error* (lambda (p) (raise-type-error tag->C error-str p))])
(let-syntax ([tag-or-error
(syntax-rules ()
[(tag-or-error ptr t)
(let ([p ptr])
(if (cpointer? p)
(unless (cpointer-has-tag? p t) (error* p))
(error* p)))])]
[tag-or-error/null
(syntax-rules ()
[(tag-or-error/null ptr t)
(let ([p ptr])
(if (cpointer? p)
(when p (unless (cpointer-has-tag? p t) (error* p)))
(error* p)))])])
(make-ctype (or ptr-type _pointer)
;; bad hack: `if's outside the lambda for efficiency
(if nullable?
(if scheme->c
(lambda (p) (tag-or-error/null (scheme->c p) tag) p)
(lambda (p) (tag-or-error/null p tag) p))
(if scheme->c
(lambda (p) (tag-or-error (scheme->c p) tag) p)
(lambda (p) (tag-or-error p tag) p)))
(if nullable?
(if c->scheme
(lambda (p) (when p (cpointer-push-tag! p tag)) (c->scheme p))
(lambda (p) (when p (cpointer-push-tag! p tag)) p))
(if c->scheme
(lambda (p)
(if p (cpointer-push-tag! p tag) (error* p))
(c->scheme p))
(lambda (p)
(if p (cpointer-push-tag! p tag) (error* p))
p))))))]))
;; This is a kind of a pointer that gets a specific tag when converted to
;; Scheme, and accepts only such tagged pointers when going to C. An optional
;; `ptr-type' can be given to be used as the base pointer type, instead of
;; _pointer, `scheme->c' and `c->scheme' can be used for adding conversion
;; hooks.
(define* _cpointer (cpointer-maker #f))
;; Similar to the above, but can tolerate null pointers (#f).
(define* _cpointer/null (cpointer-maker #t))
;; A macro version of the above two functions, using the defined name for a tag
;; string, and defining a predicate too. The name should look like `_foo', the
;; predicate will be `foo?', and the tag will be "foo". In addition, `foo-tag'
;; is bound to the tag. The optional `ptr-type', `scheme->c', and `c->scheme'
;; arguments are the same as those of `_cpointer'. `_foo' will be bound to the
;; _cpointer type, and `_foo/null' to the _cpointer/null type.
(provide define-cpointer-type)
(define-syntax (define-cpointer-type stx)
(syntax-case stx ()
[(_ _TYPE) #'(define-cpointer-type _TYPE #f #f #f)]
[(_ _TYPE ptr-type) #'(define-cpointer-type _TYPE ptr-type #f #f)]
[(_ _TYPE ptr-type scheme->c c->scheme)
(and (identifier? #'_TYPE)
(regexp-match #rx"^_.+" (symbol->string (syntax-e #'_TYPE))))
(let ([name (cadr (regexp-match #rx"^_(.+)$"
(symbol->string (syntax-e #'_TYPE))))])
(define (id . strings)
(datum->syntax
#'_TYPE (string->symbol (apply string-append strings)) #'_TYPE))
(with-syntax ([name-string name]
[TYPE? (id name "?")]
[TYPE-tag (id name "-tag")]
[_TYPE/null (id "_" name "/null")])
#'(define-values (_TYPE _TYPE/null TYPE? TYPE-tag)
(let ([TYPE-tag name-string])
(values (_cpointer TYPE-tag ptr-type scheme->c c->scheme)
(_cpointer/null TYPE-tag ptr-type scheme->c c->scheme)
(lambda (x)
(and (cpointer? x) (cpointer-has-tag? x TYPE-tag)))
TYPE-tag)))))]))
;; ----------------------------------------------------------------------------
;; Struct wrappers
(define (compute-offsets types)
(let loop ([ts types] [cur 0] [r '()])
(if (null? ts)
(reverse r)
(let* ([algn (ctype-alignof (car ts))]
[pos (+ cur (modulo (- (modulo cur algn)) algn))])
(loop (cdr ts)
(+ pos (ctype-sizeof (car ts)))
(cons pos r))))))
;; Simple structs: call this with a list of types, and get a type that marshals
;; C structs to/from Scheme lists.
(define* (_list-struct . types)
(let ([stype (make-cstruct-type types)]
[offsets (compute-offsets types)])
(make-ctype stype
(lambda (vals)
(let ([block (malloc stype)])
(for-each (lambda (type ofs val) (ptr-set! block type 'abs ofs val))
types offsets vals)
block))
(lambda (block)
(map (lambda (type ofs) (ptr-ref block type 'abs ofs))
types offsets)))))
;; (define-cstruct _foo ([slot type] ...))
;; or
;; (define-cstruct (_foo _super) ([slot type] ...))
;; defines a type called _foo for a C struct, with user-procedues: make-foo,
;; foo? foo-slot... and set-foo-slot!.... The `_' prefix is required. Objects
;; of this new type are actually cpointers, with a type tag that is "foo" and
;; (possibly more if the first type is itself a cstruct type or if a super type
;; is given,) provided as foo-tag, and tags of pointers are checked before
;; attempting to use them (see define-cpointer-type above). Note that since
;; structs are implemented as pointers, they can be used for a _pointer input
;; to a foreign function: their address will be used, to make this possible,
;; the corresponding cpointer type is defined as _foo-pointer. If a super
;; cstruct type is given, the constructor function expects values for every
;; field of the super type as well as other fields that are specified, and a
;; slot named `super' can be used to extract this initial struct -- although
;; pointers to the new struct type can be used as pointers to the super struct
;; type.
(provide define-cstruct)
(define-syntax (define-cstruct stx)
(define (make-syntax _TYPE-stx has-super? slot-names-stx slot-types-stx)
(define name
(cadr (regexp-match #rx"^_(.+)$" (symbol->string (syntax-e _TYPE-stx)))))
(define slot-names (map (lambda (x) (symbol->string (syntax-e x)))
(syntax->list slot-names-stx)))
(define 1st-type
(let ([xs (syntax->list slot-types-stx)]) (and (pair? xs) (car xs))))
(define (id . strings)
(datum->syntax
_TYPE-stx (string->symbol (apply string-append strings)) _TYPE-stx))
(define (ids name-func)
(map (lambda (s)
(datum->syntax
_TYPE-stx
(string->symbol (apply string-append (name-func s)))
_TYPE-stx))
slot-names))
(define (safe-id=? x y)
(and (identifier? x) (identifier? y) (free-identifier=? x y)))
(with-syntax
([has-super? has-super?]
[name-string name]
[struct-string (format "struct:~a" name)]
[(slot ...) slot-names-stx]
[(slot-type ...) slot-types-stx]
[_TYPE _TYPE-stx]
[_TYPE-pointer (id "_"name"-pointer")]
[_TYPE-pointer/null (id "_"name"-pointer/null")]
[_TYPE/null (id "_"name"/null")]
[_TYPE* (id "_"name"*")]
[TYPE? (id name"?")]
[make-TYPE (id "make-"name)]
[list->TYPE (id "list->"name)]
[list*->TYPE (id "list*->"name)]
[TYPE->list (id name"->list")]
[TYPE->list* (id name"->list*")]
[TYPE-tag (id name"-tag")]
[(stype ...) (ids (lambda (s) `(,name"-",s"-type")))]
[(TYPE-SLOT ...) (ids (lambda (s) `(,name"-",s)))]
[(set-TYPE-SLOT! ...) (ids (lambda (s) `("set-",name"-",s"!")))]
[(offset ...) (generate-temporaries
(ids (lambda (s) `(,s"-offset"))))])
(with-syntax ([get-super-info
;; the 1st-type might be a pointer to this type
(if (or (safe-id=? 1st-type #'_TYPE-pointer/null)
(safe-id=? 1st-type #'_TYPE-pointer))
#'(values #f '() #f #f #f #f)
#`(cstruct-info #,1st-type
(lambda () (values #f '() #f #f #f #f))))])
#'(define-values (_TYPE _TYPE-pointer _TYPE-pointer/null TYPE? TYPE-tag
make-TYPE TYPE-SLOT ... set-TYPE-SLOT! ...
list->TYPE list*->TYPE TYPE->list TYPE->list*)
(let-values ([(super-pointer super-tags super-types super-offsets
super->list* list*->super)
get-super-info])
(define-cpointer-type _TYPE super-pointer)
;; these makes it possible to use recursive pointer definitions
(define _TYPE-pointer _TYPE)
(define _TYPE-pointer/null _TYPE/null)
(let*-values ([(stype ...) (values slot-type ...)]
[(types) (list stype ...)]
[(offsets) (compute-offsets types)]
[(offset ...) (apply values offsets)])
(define all-tags (cons TYPE-tag super-tags))
(define _TYPE*
;; c->scheme adjusts all tags
(let* ([t (_cpointer TYPE-tag (make-cstruct-type types))]
[c->s (ctype-c->scheme t)])
(make-ctype (ctype-basetype t) (ctype-scheme->c t)
;; hack: modify & reuse the procedure made by _cpointer
(lambda (p)
(if p (set-cpointer-tag! p all-tags) (c->s p))
p))))
(define-values (all-types all-offsets)
(if (and has-super? super-types super-offsets)
(values (append super-types (cdr types))
(append super-offsets (cdr offsets)))
(values types offsets)))
(define (TYPE-SLOT x)
(unless (TYPE? x)
(raise-type-error 'TYPE-SLOT struct-string x))
(ptr-ref x stype 'abs offset))
...
(define (set-TYPE-SLOT! x slot)
(unless (TYPE? x)
(raise-type-error 'set-TYPE-SLOT! struct-string 0 x slot))
(ptr-set! x stype 'abs offset slot))
...
(define make-TYPE
(if (and has-super? super-types super-offsets)
;; init using all slots
(lambda vals
(if (= (length vals) (length all-types))
(let ([block (malloc _TYPE*)])
(set-cpointer-tag! block all-tags)
(for-each (lambda (type ofs value)
(ptr-set! block type 'abs ofs value))
all-types all-offsets vals)
block)
(error '_TYPE "expecting ~s values, got ~s: ~e"
(length all-types) (length vals) vals)))
;; normal initializer
(lambda (slot ...)
(let ([block (malloc _TYPE*)])
(set-cpointer-tag! block all-tags)
(ptr-set! block stype 'abs offset slot)
...
block))))
(define (list->TYPE vals) (apply make-TYPE vals))
(define (list*->TYPE vals)
(cond
[(TYPE? vals) vals]
[(= (length vals) (length all-types))
(let ([block (malloc _TYPE*)])
(set-cpointer-tag! block all-tags)
(for-each
(lambda (type ofs value)
(let-values
([(ptr tags types offsets T->list* list*->T)
(cstruct-info
type
(lambda () (values #f '() #f #f #f #f)))])
(ptr-set! block type 'abs ofs
(if list*->T (list*->T value) value))))
all-types all-offsets vals)
block)]
[else (error '_TYPE "expecting ~s values, got ~s: ~e"
(length all-types) (length vals) vals)]))
(define (TYPE->list x)
(unless (TYPE? x)
(raise-type-error 'TYPE-list struct-string x))
(map (lambda (type ofs) (ptr-ref x type 'abs ofs))
all-types all-offsets))
(define (TYPE->list* x)
(unless (TYPE? x)
(raise-type-error 'TYPE-list struct-string x))
(map (lambda (type ofs)
(let-values
([(v) (ptr-ref x type 'abs ofs)]
[(ptr tags types offsets T->list* list*->T)
(cstruct-info
type
(lambda () (values #f '() #f #f #f #f)))])
(if T->list* (T->list* v) v)))
all-types all-offsets))
(cstruct-info
_TYPE* 'set!
_TYPE all-tags all-types all-offsets TYPE->list* list*->TYPE)
(values _TYPE* _TYPE-pointer _TYPE-pointer/null TYPE? TYPE-tag
make-TYPE TYPE-SLOT ... set-TYPE-SLOT! ...
list->TYPE list*->TYPE TYPE->list TYPE->list*)))))))
(define (identifiers? stx)
(andmap identifier? (syntax->list stx)))
(define (_-identifier? stx)
(and (identifier? stx)
(regexp-match #rx"^_.+" (symbol->string (syntax-e stx)))))
(syntax-case stx ()
[(_ _TYPE ([slot slot-type] ...))
(and (_-identifier? #'_TYPE) (identifiers? #'(slot ...)))
(make-syntax #'_TYPE #f #'(slot ...) #'(slot-type ...))]
[(_ (_TYPE _SUPER) ([slot slot-type] ...))
(and (_-identifier? #'_TYPE) (identifiers? #'(slot ...)))
(with-syntax ([super (datum->syntax #'_TYPE 'super #'_TYPE)])
(make-syntax #'_TYPE #t #'(super slot ...) #'(_SUPER slot-type ...)))]))
;; helper for the above: keep runtime information on structs
(define cstruct-info
(let ([table (make-weak-hasheq)])
(lambda (cstruct msg/fail-thunk . args)
(cond [(eq? 'set! msg/fail-thunk)
(hash-set! table cstruct (make-ephemeron cstruct args))]
[(and cstruct ; might get a #f if there were no slots
(hash-ref table cstruct (lambda () #f)))
=> (lambda (xs)
(let ([v (ephemeron-value xs)])
(if v
(apply values v)
(msg/fail-thunk))))]
[else (msg/fail-thunk)]))))
;; ----------------------------------------------------------------------------
;; Misc utilities
;; Used by set-ffi-obj! to get the actual value so it can be kept around
(define (get-lowlevel-object x type)
(let ([basetype (ctype-basetype type)])
(if basetype
(let ([s->c (ctype-scheme->c type)])
(get-lowlevel-object (if s->c (s->c x) x) basetype))
(values x type))))
;; Converting Scheme lists to/from C vectors (going back requires a length)
(define* (list->cblock l type)
(if (null? l)
#f ; null => NULL
(let ([cblock (malloc (length l) type)])
(let loop ([l l] [i 0])
(unless (null? l)
(ptr-set! cblock type i (car l))
(loop (cdr l) (add1 i))))
cblock)))
(provide* (unsafe cblock->list))
(define (cblock->list cblock type len)
(cond [(zero? len) '()]
[(cpointer? cblock)
(let loop ([i (sub1 len)] [r '()])
(if (< i 0)
r
(loop (sub1 i) (cons (ptr-ref cblock type i) r))))]
[else (error 'cblock->list
"expecting a non-void pointer, got ~s" cblock)]))
;; Converting Scheme vectors to/from C vectors
(define* (vector->cblock v type)
(let ([len (vector-length v)])
(if (zero? len)
#f ; #() => NULL
(let ([cblock (malloc len type)])
(let loop ([i 0])
(when (< i len)
(ptr-set! cblock type i (vector-ref v i))
(loop (add1 i))))
cblock))))
(provide* (unsafe cblock->vector))
(define (cblock->vector cblock type len)
(cond [(zero? len) '#()]
[(cpointer? cblock)
(let ([v (make-vector len)])
(let loop ([i (sub1 len)])
(unless (< i 0)
(vector-set! v i (ptr-ref cblock type i))
(loop (sub1 i))))
v)]
[else (error 'cblock->vector
"expecting a non-void pointer, got ~s" cblock)]))
;; Useful for automatic definitions
;; If a provided regexp begins with a "^" or ends with a "$", then
;; `regexp-replace' is used, otherwise use `regexp-replace*'.
(define* (regexp-replaces x rs)
(let loop ([str (if (bytes? x) (bytes->string/utf-8 x) (format "~a" x))]
[rs rs])
(if (null? rs)
str
(loop ((if (regexp-match #rx"^\\^|\\$$"
(if (regexp? (caar rs))
(object-name (caar rs)) (caar rs)))
regexp-replace regexp-replace*)
(caar rs) str (cadar rs)) (cdr rs)))))
;; A facility for running finalizers using executors. #%foreign has a C-based
;; version that uses finalizers, but that leads to calling Scheme from the GC
;; which is not a good idea.
(define killer-executor (make-will-executor))
(define killer-thread #f)
(provide* (unsafe register-finalizer))
(define (register-finalizer obj finalizer)
(unless killer-thread
(set! killer-thread
(thread (lambda ()
(let loop () (will-execute killer-executor) (loop))))))
(will-register killer-executor obj finalizer))
(define-unsafer unsafe!)