19 lines
518 B
Scheme
19 lines
518 B
Scheme
(define-record-type resource :resource
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(make-resource align! lock)
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resource?
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(align! resource-align!)
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(lock resource-lock))
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(define (with-resources-aligned resources thunk)
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(let ((locks (map resource-lock resources)))
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(apply obtain-all-or-none locks)
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(for-each
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(lambda (align!) (align!))
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(map resource-align! resources))
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(let ((val (with-handler
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(lambda (cond more)
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(for-each release-lock locks)
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(more))
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thunk)))
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(for-each release-lock locks)
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val))) |