gnucash/libgnucash/app-utils/c-interface.scm
Christopher Lam d56a47f17a [c-interface] gnc:backtrace-if-exception returns #f if error
previous would return *unspecified* when error was captured.
old code seems to expect #f to signal error
2019-11-03 10:44:50 +08:00

96 lines
4.1 KiB
Scheme

;; This program is free software; you can redistribute it and/or
;; modify it under the terms of the GNU General Public License as
;; published by the Free Software Foundation; either version 2 of
;; the License, or (at your option) any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; if not, contact:
;;
;; Free Software Foundation Voice: +1-617-542-5942
;; 51 Franklin Street, Fifth Floor Fax: +1-617-542-2652
;; Boston, MA 02110-1301, USA gnu@gnu.org
(define (gnc:call-with-error-handling cmd args)
(let ((captured-stack #f)
(captured-error #f)
(result #f))
(catch #t
(lambda ()
;; Execute the code in which you want to catch errors here.
(cond
((procedure? cmd) (set! result (apply cmd args)))
((string? cmd) (set! result (eval-string cmd)))))
(lambda (key . parameters)
;; Put the code which you want to handle an error after the
;; stack has been unwound here.
(set! captured-error
(call-with-output-string
(lambda (port)
(display-backtrace captured-stack port)
(newline port)
(print-exception port #f key parameters)))))
(lambda (key . parameters)
;; Capture the stack here, cut the last 3 frames which are
;; make-stack, this one, and the throw handler.
(set! captured-stack (make-stack #t 3))))
(list result captured-error)))
;; gnc:eval-string-with-error-handling will evaluate the input string (cmd)
;; an captures any exception that would be generated. It returns
;; a list with 2 elements: the output of the evaluation and a backtrace.
;; The first may be set if string evaluation did generate
;; output, the latter is set when an exception was caught.
;; We'll use this to wrap guile calls in C(++), allowing
;; the C(++) code to decide how to handle the errors.
(define (gnc:eval-string-with-error-handling cmd)
(gnc:call-with-error-handling cmd '()))
;; gnc:apply-with-error-handling will call guile's apply to run func with args
;; an captures any exception that would be generated. It returns
;; a list with 2 elements: the output of the evaluation and a backtrace.
;; The first may be set if the result of the apply did generate
;; output, the latter is set when an exception was caught.
;; We'll use this to wrap guile calls in C(++), allowing
;; the C(++) code to decide how to handle the errors.
(define (gnc:apply-with-error-handling func args)
(gnc:call-with-error-handling func args))
(define (gnc:backtrace-if-exception proc . args)
(let* ((apply-result (gnc:apply-with-error-handling proc args))
(result (car apply-result))
(captured-error (cadr apply-result)))
(cond
(captured-error
(display captured-error (current-error-port))
(set! gnc:last-captured-error (gnc:html-string-sanitize captured-error))
(when (defined? 'gnc:warn)
(gnc:warn captured-error))
#f)
(else result))))
(define-public gnc:last-captured-error "")
;; This database can be used to store and retrieve translatable
;; strings. Strings that are returned by the lookup function are
;; translated with gettext.
(define (gnc:make-string-database)
(define string-hash (make-hash-table))
(define (lookup key)
(_ (hash-ref string-hash key)))
(define (store key string)
(hash-set! string-hash key string))
(define (dispatch message . args)
(let ((func (case message
((lookup) lookup)
((store) store)
(else #f))))
(if func
(apply func args)
(gnc:warn "string-database: bad message" message "\n"))))
dispatch)