adamc@732: (* Copyright (c) 2009, Adam Chlipala
adamc@732:  * All rights reserved.
adamc@732:  *
adamc@732:  * Redistribution and use in source and binary forms, with or without
adamc@732:  * modification, are permitted provided that the following conditions are met:
adamc@732:  *
adamc@732:  * - Redistributions of source code must retain the above copyright notice,
adamc@732:  *   this list of conditions and the following disclaimer.
adamc@732:  * - Redistributions in binary form must reproduce the above copyright notice,
adamc@732:  *   this list of conditions and the following disclaimer in the documentation
adamc@732:  *   and/or other materials provided with the distribution.
adamc@732:  * - The names of contributors may not be used to endorse or promote products
adamc@732:  *   derived from this software without specific prior written permission.
adamc@732:  *
adamc@732:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
adamc@732:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
adamc@732:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
adamc@732:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
adamc@732:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
adamc@732:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
adamc@732:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
adamc@732:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
adamc@732:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
adamc@732:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
adamc@732:  * POSSIBILITY OF SUCH DAMAGE.
adamc@732:  *)
adamc@732: 
adamc@732: structure Effective :> EFFECTIZE = struct
adamc@732: 
adamc@732: open Core
adamc@732: 
adamc@732: structure U = CoreUtil
adamc@732: 
adamc@732: structure IM = IntBinaryMap
adamc@732: structure SS = BinarySetFn(struct
adamc@732:                            type ord_key = string
adamc@732:                            val compare = String.compare
adamc@732:                            end)
adamc@732: 
adamc@735: val effectful = ["dml", "nextval", "send", "setCookie"]
adamc@732: val effectful = SS.addList (SS.empty, effectful)
adamc@732: 
adamc@732: fun effectize file =
adamc@732:     let
adamc@732:         fun exp evs e =
adamc@732:             case e of
adamc@732:                 EFfi ("Basis", s) => SS.member (effectful, s)
adamc@732:               | EFfiApp ("Basis", s, _) => SS.member (effectful, s)
adamc@732:               | ENamed n => IM.inDomain (evs, n)
adamc@732:               | EServerCall (n, _, _, _) => IM.inDomain (evs, n)
adamc@732:               | _ => false
adamc@732: 
adamc@732:         fun couldWrite evs = U.Exp.exists {kind = fn _ => false,
adamc@732:                                            con = fn _ => false,
adamc@732:                                            exp = exp evs}
adamc@732: 
adamc@735:         fun exp evs e =
adamc@735:             case e of
adamc@735:                 EFfi ("Basis", "getCookie") => true
adamc@735:               | ENamed n => IM.inDomain (evs, n)
adamc@735:               | EServerCall (n, _, _, _) => IM.inDomain (evs, n)
adamc@735:               | _ => false
adamc@735: 
adamc@735:         fun couldReadCookie evs = U.Exp.exists {kind = fn _ => false,
adamc@735:                                                 con = fn _ => false,
adamc@735:                                                 exp = exp evs}
adamc@735: 
adamc@735:         fun doDecl (d, evs as (writers, readers)) =
adamc@732:             case #1 d of
adamc@732:                 DVal (x, n, t, e, s) =>
adamc@735:                 (d, (if couldWrite writers e then
adamc@735:                          IM.insert (writers, n, (#2 d, s))
adamc@735:                      else
adamc@735:                          writers,
adamc@735:                      if couldReadCookie readers e then
adamc@735:                          IM.insert (readers, n, (#2 d, s))
adamc@735:                      else
adamc@735:                          readers))
adamc@732:               | DValRec vis =>
adamc@732:                 let
adamc@732:                     fun oneRound evs =
adamc@735:                         foldl (fn ((_, n, _, e, s), (changed, (writers, readers))) =>
adamc@735:                                   let
adamc@735:                                       val (changed, writers) =
adamc@735:                                           if couldWrite writers e andalso not (IM.inDomain (writers, n)) then
adamc@735:                                               (true, IM.insert (writers, n, (#2 d, s)))
adamc@735:                                           else
adamc@735:                                               (changed, writers)
adamc@735: 
adamc@735:                                       val (changed, readers) =
adamc@735:                                           if couldReadCookie readers e andalso not (IM.inDomain (readers, n)) then
adamc@735:                                               (true, IM.insert (readers, n, (#2 d, s)))
adamc@735:                                           else
adamc@735:                                               (changed, readers)
adamc@735:                                   in
adamc@735:                                       (changed, (writers, readers))
adamc@735:                                   end) (false, evs) vis
adamc@732: 
adamc@732:                     fun loop evs =
adamc@732:                         let
adamc@732:                             val (b, evs) = oneRound evs
adamc@732:                         in
adamc@732:                             if b then
adamc@732:                                 loop evs
adamc@732:                             else
adamc@732:                                 evs
adamc@732:                         end
adamc@732:                 in
adamc@735:                     (d, loop (writers, readers))
adamc@732:                 end
adamc@732:               | DExport (Link, n) =>
adamc@735:                 (case IM.find (writers, n) of
adamc@732:                      NONE => ()
adamc@732:                    | SOME (loc, s) => ErrorMsg.errorAt loc ("A link (" ^ s ^ ") could cause side effects; try implementing it with a form instead");
adamc@732:                  (d, evs))
adamc@732:               | DExport (Action _, n) =>
adamc@735:                 ((DExport (Action (if IM.inDomain (writers, n) then
adamc@735:                                        if IM.inDomain (readers, n) then
adamc@735:                                            ReadCookieWrite
adamc@735:                                        else
adamc@735:                                            ReadWrite
adamc@732:                                    else
adamc@732:                                        ReadOnly), n), #2 d),
adamc@732:                  evs)
adamc@732:               | DExport (Rpc _, n) =>
adamc@735:                 ((DExport (Rpc (if IM.inDomain (writers, n) then
adamc@735:                                     if IM.inDomain (readers, n) then
adamc@735:                                         ReadCookieWrite
adamc@735:                                     else
adamc@735:                                         ReadWrite
adamc@732:                                 else
adamc@732:                                     ReadOnly), n), #2 d),
adamc@732:                  evs)
adamc@732:               | _ => (d, evs)
adamc@732: 
adamc@735:         val (file, _) = ListUtil.foldlMap doDecl (IM.empty, IM.empty) file
adamc@732:     in
adamc@732:         file
adamc@732:     end
adamc@732: 
adamc@732: end