  Copyright ( c ) 2011 - 2012 ,    . All rights reserved .
;;;
;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:
;;;
;;;     * Redistributions of source code must retain the above copyright
;;;       notice, this list of conditions and the following disclaimer.
;;;
;;;     * Redistributions in binary form must reproduce the above
;;;       copyright notice, this list of conditions and the following
;;;       disclaimer in the documentation and/or other materials provided
;;;       with the distribution.
;;;
;;;     * Neither the name of the project nor the names of its
;;;       contributors may be used to endorse or promote products derived
;;;       from this software without specific prior written permission.
;;;
;;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT
;;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  HOLDER OR    FOR ANY DIRECT , INDIRECT , INCIDENTAL ,
  SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT
  LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE ,
;;; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT
;;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
;;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

(defpackage #:lparallel.kernel-util
  (:documentation
   "(semi-private) Abstracts some common patterns for submitting and
   receiving tasks. This probably won't change, but no guarantees.")
  (:use #:cl
        #:lparallel.util
        #:lparallel.kernel
        #:lparallel.queue)
  (:export #:with-submit-counted
           #:submit-counted
           #:receive-counted)
  (:export #:with-submit-indexed
           #:submit-indexed
           #:receive-indexed)
  (:export #:with-submit-cancelable
           #:submit-cancelable
           #:receive-cancelables)
  (:export #:with-temp-kernel)
  (:import-from #:lparallel.kernel
                #:*worker*
                #:steal-work
                #:channel-kernel))

(in-package #:lparallel.kernel-util)

(defun steal-until-receive-result (channel worker fn)
  (declare #.*normal-optimize*)
  (loop
     (multiple-value-bind (result presentp) (try-receive-result channel)
       (when presentp
         (when fn
           (locally (declare (type function fn))
             (funcall fn result)))
         (return)))
     (steal-work (channel-kernel channel) worker)))

(defun receive-results (channel count fn)
  (declare #.*normal-optimize*)
  (let ((worker *worker*))
    (if worker
        (repeat count
          (steal-until-receive-result channel worker fn))
        (if fn
            (do-fast-receives (result channel count)
              (locally (declare (type function fn))
                (funcall fn result)))
            (do-fast-receives (result channel count)
              (declare (ignore result)))))))

(defmacro with-submit-counted (&body body)
  (with-gensyms (count channel)
    `(let ((,count 0)
           (,channel (make-channel)))
       (declare (fixnum ,count))
       (flet ((submit-counted (&rest args)
                (declare (dynamic-extent args))
                (apply #'submit-task ,channel args)
                (incf ,count))
              (receive-counted ()
                (receive-results ,channel ,count nil)))
         (declare (inline submit-counted receive-counted))
         ,@body))))

(defun indexing-wrapper (array index function args)
  (setf (aref array index) (apply function args)))

(defmacro/once with-submit-indexed (&once count &once array &body body)
  (with-gensyms (channel)
    `(let ((,channel (make-channel)))
       (flet ((submit-indexed (index function &rest args)
                (submit-task
                 ,channel #'indexing-wrapper ,array index function args))
              (receive-indexed ()
                (receive-results ,channel ,count nil)
                ,array))
         (declare (inline submit-indexed receive-indexed))
         ,@body))))

(defmacro with-submit-cancelable (&body body)
  (with-gensyms (canceledp channel count)
    `(let ((,canceledp nil)
           (,count 0)
           (,channel (make-channel)))
       (flet ((submit-cancelable (fn &rest args)
                (submit-task ,channel
                             (lambda ()
                               (if ,canceledp
                                   'task-canceled
                                   (apply fn args))))
                (incf ,count)))
         (macrolet ((receive-cancelables (result &body body)
                      `(receive-results
                        ,',channel ,',count (lambda (,result) ,@body))))
           (unwind-protect (progn ,@body)
             (setf ,canceledp t)))))))

(defun call-with-temp-kernel (fn &rest args)
  ;; ensure that we end the same kernel we create
  (let ((kernel (apply #'make-kernel args)))
    (unwind-protect
         (let ((*kernel* kernel))
           (funcall fn))
      (let ((*kernel* kernel))
        (end-kernel :wait t)))))

(defmacro with-temp-kernel ((&rest make-kernel-args) &body body)
  "Create a temporary kernel for the duration of `body', ensuring that
`end-kernel' is eventually called. `make-kernel' is given the
arguments `make-kernel-args'.

**NOTE**: Use this only if you understand its implications. Since
`*kernel*' is unaffected outside `body', the REPL will be useless with
respect to the temporary kernel. For instance calling `kill-tasks'
from the REPL will not affect tasks that are running in the temporary
kernel.

Multiple uses of `with-temp-kernel' within the same application are
prone to defeat the purpose and benefits of having a thread pool. This
is an especial risk if `with-temp-kernel' appears inside a library,
which is likely to be a suboptimal situation.

While using `with-temp-kernel' is generally a bad idea, there are a
few valid uses, such as for testing, where the code is non-critical or
where convenience trumps other concerns."
  `(call-with-temp-kernel (lambda () ,@body) ,@make-kernel-args))


 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:

     * Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

     * Redistributions in binary form must reproduce the above
       copyright notice, this list of conditions and the following
       disclaimer in the documentation and/or other materials provided
       with the distribution.

     * Neither the name of the project nor the names of its
       contributors may be used to endorse or promote products derived
       from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 LOSS OF USE ,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ensure that we end the same kernel we create
  Copyright ( c ) 2011 - 2012 ,    . All rights reserved .
  " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT
  HOLDER OR    FOR ANY DIRECT , INDIRECT , INCIDENTAL ,
  SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT
  THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT

(defpackage #:lparallel.kernel-util
  (:documentation
   "(semi-private) Abstracts some common patterns for submitting and
   receiving tasks. This probably won't change, but no guarantees.")
  (:use #:cl
        #:lparallel.util
        #:lparallel.kernel
        #:lparallel.queue)
  (:export #:with-submit-counted
           #:submit-counted
           #:receive-counted)
  (:export #:with-submit-indexed
           #:submit-indexed
           #:receive-indexed)
  (:export #:with-submit-cancelable
           #:submit-cancelable
           #:receive-cancelables)
  (:export #:with-temp-kernel)
  (:import-from #:lparallel.kernel
                #:*worker*
                #:steal-work
                #:channel-kernel))

(in-package #:lparallel.kernel-util)

(defun steal-until-receive-result (channel worker fn)
  (declare #.*normal-optimize*)
  (loop
     (multiple-value-bind (result presentp) (try-receive-result channel)
       (when presentp
         (when fn
           (locally (declare (type function fn))
             (funcall fn result)))
         (return)))
     (steal-work (channel-kernel channel) worker)))

(defun receive-results (channel count fn)
  (declare #.*normal-optimize*)
  (let ((worker *worker*))
    (if worker
        (repeat count
          (steal-until-receive-result channel worker fn))
        (if fn
            (do-fast-receives (result channel count)
              (locally (declare (type function fn))
                (funcall fn result)))
            (do-fast-receives (result channel count)
              (declare (ignore result)))))))

(defmacro with-submit-counted (&body body)
  (with-gensyms (count channel)
    `(let ((,count 0)
           (,channel (make-channel)))
       (declare (fixnum ,count))
       (flet ((submit-counted (&rest args)
                (declare (dynamic-extent args))
                (apply #'submit-task ,channel args)
                (incf ,count))
              (receive-counted ()
                (receive-results ,channel ,count nil)))
         (declare (inline submit-counted receive-counted))
         ,@body))))

(defun indexing-wrapper (array index function args)
  (setf (aref array index) (apply function args)))

(defmacro/once with-submit-indexed (&once count &once array &body body)
  (with-gensyms (channel)
    `(let ((,channel (make-channel)))
       (flet ((submit-indexed (index function &rest args)
                (submit-task
                 ,channel #'indexing-wrapper ,array index function args))
              (receive-indexed ()
                (receive-results ,channel ,count nil)
                ,array))
         (declare (inline submit-indexed receive-indexed))
         ,@body))))

(defmacro with-submit-cancelable (&body body)
  (with-gensyms (canceledp channel count)
    `(let ((,canceledp nil)
           (,count 0)
           (,channel (make-channel)))
       (flet ((submit-cancelable (fn &rest args)
                (submit-task ,channel
                             (lambda ()
                               (if ,canceledp
                                   'task-canceled
                                   (apply fn args))))
                (incf ,count)))
         (macrolet ((receive-cancelables (result &body body)
                      `(receive-results
                        ,',channel ,',count (lambda (,result) ,@body))))
           (unwind-protect (progn ,@body)
             (setf ,canceledp t)))))))

(defun call-with-temp-kernel (fn &rest args)
  (let ((kernel (apply #'make-kernel args)))
    (unwind-protect
         (let ((*kernel* kernel))
           (funcall fn))
      (let ((*kernel* kernel))
        (end-kernel :wait t)))))

(defmacro with-temp-kernel ((&rest make-kernel-args) &body body)
  "Create a temporary kernel for the duration of `body', ensuring that
`end-kernel' is eventually called. `make-kernel' is given the
arguments `make-kernel-args'.

**NOTE**: Use this only if you understand its implications. Since
`*kernel*' is unaffected outside `body', the REPL will be useless with
respect to the temporary kernel. For instance calling `kill-tasks'
from the REPL will not affect tasks that are running in the temporary
kernel.

Multiple uses of `with-temp-kernel' within the same application are
prone to defeat the purpose and benefits of having a thread pool. This
is an especial risk if `with-temp-kernel' appears inside a library,
which is likely to be a suboptimal situation.

While using `with-temp-kernel' is generally a bad idea, there are a
few valid uses, such as for testing, where the code is non-critical or
where convenience trumps other concerns."
  `(call-with-temp-kernel (lambda () ,@body) ,@make-kernel-args))
