#
#
# Nimrod's Runtime Library
# (c) Copyright 2011 Andreas Rumpf
#
# See the file "copying.txt", included in this
# distribution, for details about the copyright.
#
## Message passing for threads. The current implementation is slow and does
## not work with cyclic data structures. But hey, it's better than nothing.
type
pbytes = ptr array[0.. 0xffff, byte]
TInbox {.pure, final.} = object ## msg queue for a thread
rd, wr, count, mask: int
data: pbytes
lock: TSysLock
cond: TSysCond
elemType: PNimType
region: TMemRegion
PInbox = ptr TInbox
TLoadStoreMode = enum mStore, mLoad
const ThreadDeadMask = -2
proc initInbox(p: pointer) =
var inbox = cast[PInbox](p)
initSysLock(inbox.lock)
initSysCond(inbox.cond)
inbox.mask = -1
proc freeInbox(p: pointer) =
var inbox = cast[PInbox](p)
# we need to grab the lock to be save against sending threads!
acquireSys(inbox.lock)
inbox.mask = ThreadDeadMask
deallocOsPages(inbox.region)
deinitSys(inbox.lock)
deinitSysCond(inbox.cond)
proc storeAux(dest, src: Pointer, mt: PNimType, t: PInbox, mode: TLoadStoreMode)
proc storeAux(dest, src: Pointer, n: ptr TNimNode, t: PInbox,
mode: TLoadStoreMode) =
var
d = cast[TAddress](dest)
s = cast[TAddress](src)
case n.kind
of nkSlot: storeAux(cast[pointer](d +% n.offset),
cast[pointer](s +% n.offset), n.typ, t, mode)
of nkList:
for i in 0..n.len-1: storeAux(dest, src, n.sons[i], t, mode)
of nkCase:
copyMem(cast[pointer](d +% n.offset), cast[pointer](s +% n.offset),
n.typ.size)
var m = selectBranch(src, n)
if m != nil: storeAux(dest, src, m, t, mode)
of nkNone: sysAssert(false)
proc storeAux(dest, src: Pointer, mt: PNimType, t: PInbox,
mode: TLoadStoreMode) =
var
d = cast[TAddress](dest)
s = cast[TAddress](src)
sysAssert(mt != nil)
case mt.Kind
of tyString:
if mode == mStore:
var x = cast[ppointer](dest)
var s2 = cast[ppointer](s)[]
if s2 == nil:
x[] = nil
else:
var ss = cast[NimString](s2)
var ns = cast[NimString](rawAlloc(t.region, ss.len+1 + GenericSeqSize))
copyMem(ns, ss, ss.len+1 + GenericSeqSize)
x[] = ns
else:
var x = cast[ppointer](dest)
var s2 = cast[ppointer](s)[]
if s2 == nil:
unsureAsgnRef(x, s2)
else:
unsureAsgnRef(x, copyString(cast[NimString](s2)))
rawDealloc(t.region, s2)
of tySequence:
var s2 = cast[ppointer](src)[]
var seq = cast[PGenericSeq](s2)
var x = cast[ppointer](dest)
if s2 == nil:
if mode == mStore:
x[] = nil
else:
unsureAsgnRef(x, nil)
else:
sysAssert(dest != nil)
if mode == mStore:
x[] = rawAlloc(t.region, seq.len *% mt.base.size +% GenericSeqSize)
else:
unsureAsgnRef(x, newObj(mt, seq.len * mt.base.size + GenericSeqSize))
var dst = cast[taddress](cast[ppointer](dest)[])
for i in 0..seq.len-1:
storeAux(
cast[pointer](dst +% i*% mt.base.size +% GenericSeqSize),
cast[pointer](cast[TAddress](s2) +% i *% mt.base.size +%
GenericSeqSize),
mt.Base, t, mode)
var dstseq = cast[PGenericSeq](dst)
dstseq.len = seq.len
dstseq.space = seq.len
if mode != mStore: rawDealloc(t.region, s2)
of tyObject:
# copy type field:
var pint = cast[ptr PNimType](dest)
# XXX use dynamic type here!
pint[] = mt
storeAux(dest, src, mt.node, t, mode)
of tyTuple, tyPureObject:
storeAux(dest, src, mt.node, t, mode)
of tyArray, tyArrayConstr:
for i in 0..(mt.size div mt.base.size)-1:
storeAux(cast[pointer](d +% i*% mt.base.size),
cast[pointer](s +% i*% mt.base.size), mt.base, t, mode)
of tyRef:
var s = cast[ppointer](src)[]
var x = cast[ppointer](dest)
if s == nil:
if mode == mStore:
x[] = nil
else:
unsureAsgnRef(x, nil)
else:
if mode == mStore:
x[] = rawAlloc(t.region, mt.base.size)
else:
# XXX we should use the dynamic type here too, but that is not stored in
# the inbox at all --> use source[]'s object type? but how? we need a
# tyRef to the object!
var obj = newObj(mt.base, mt.base.size)
unsureAsgnRef(x, obj)
storeAux(x[], s, mt.base, t, mode)
if mode != mStore: rawDealloc(t.region, s)
else:
copyMem(dest, src, mt.size) # copy raw bits
proc rawSend(q: PInbox, data: pointer, typ: PNimType) =
## adds an `item` to the end of the queue `q`.
var cap = q.mask+1
if q.count >= cap:
# start with capicity for 2 entries in the queue:
if cap == 0: cap = 1
var n = cast[pbytes](rawAlloc0(q.region, cap*2*typ.size))
var z = 0
var i = q.rd
var c = q.count
while c > 0:
dec c
copyMem(addr(n[z*typ.size]), addr(q.data[i*typ.size]), typ.size)
i = (i + 1) and q.mask
inc z
if q.data != nil: rawDealloc(q.region, q.data)
q.data = n
q.mask = cap*2 - 1
q.wr = q.count
q.rd = 0
storeAux(addr(q.data[q.wr * typ.size]), data, typ, q, mStore)
inc q.count
q.wr = (q.wr + 1) and q.mask
proc rawRecv(q: PInbox, data: pointer, typ: PNimType) =
assert q.count > 0
dec q.count
storeAux(data, addr(q.data[q.rd * typ.size]), typ, q, mLoad)
q.rd = (q.rd + 1) and q.mask
template lockInbox(q: expr, action: stmt) =
acquireSys(q.lock)
action
releaseSys(q.lock)
proc send*[TMsg](receiver: var TThread[TMsg], msg: TMsg) =
## sends a message to a thread. `msg` is deeply copied.
var q = cast[PInbox](getInBoxMem(receiver))
if q.mask == ThreadDeadMask:
raise newException(EDeadThread, "cannot send message; thread died")
acquireSys(q.lock)
var m: TMsg
shallowCopy(m, msg)
var typ = cast[PNimType](getTypeInfo(msg))
rawSend(q, addr(m), typ)
q.elemType = typ
releaseSys(q.lock)
SignalSysCond(q.cond)
proc llRecv(res: pointer, typ: PNimType) =
# to save space, the generic is as small as possible
var q = cast[PInbox](getInBoxMem())
acquireSys(q.lock)
while q.count <= 0:
WaitSysCond(q.cond, q.lock)
if typ != q.elemType:
releaseSys(q.lock)
raise newException(EInvalidValue, "cannot receive message of wrong type")
rawRecv(q, res, typ)
releaseSys(q.lock)
proc recv*[TMsg](): TMsg =
## receives a message from its internal message queue. This blocks until
## a message has arrived! You may use ``peek`` to avoid the blocking.
llRecv(addr(result), cast[PNimType](getTypeInfo(result)))
proc peek*(): int =
## returns the current number of messages in the inbox.
var q = cast[PInbox](getInBoxMem())
lockInbox(q):
result = q.count