diff options
Diffstat (limited to 'lib/system/channels.nim')
| -rw-r--r-- | lib/system/channels.nim | 522 |
1 files changed, 261 insertions, 261 deletions
diff --git a/lib/system/channels.nim b/lib/system/channels.nim index 6739fb83e..68c0e32d2 100644 --- a/lib/system/channels.nim +++ b/lib/system/channels.nim @@ -1,267 +1,267 @@ -# -# -# Nim's Runtime Library +# +# +# Nim's Runtime Library # (c) Copyright 2015 Andreas Rumpf -# -# See the file "copying.txt", included in this -# distribution, for details about the copyright. -# - -## Channel support for threads. **Note**: This is part of the system module. -## Do not import it directly. To activate thread support you need to compile -## with the ``--threads:on`` command line switch. -## -## **Note:** The current implementation of message passing is slow and does -## not work with cyclic data structures. - -when not declared(NimString): - {.error: "You must not import this module explicitly".} - -type - pbytes = ptr array[0.. 0xffff, byte] - RawChannel {.pure, final.} = object ## msg queue for a thread - rd, wr, count, mask: int - data: pbytes - lock: SysLock - cond: SysCond - elemType: PNimType - ready: bool - region: MemRegion - PRawChannel = ptr RawChannel - LoadStoreMode = enum mStore, mLoad +# +# See the file "copying.txt", included in this +# distribution, for details about the copyright. +# + +## Channel support for threads. **Note**: This is part of the system module. +## Do not import it directly. To activate thread support you need to compile +## with the ``--threads:on`` command line switch. +## +## **Note:** The current implementation of message passing is slow and does +## not work with cyclic data structures. + +when not declared(NimString): + {.error: "You must not import this module explicitly".} + +type + pbytes = ptr array[0.. 0xffff, byte] + RawChannel {.pure, final.} = object ## msg queue for a thread + rd, wr, count, mask: int + data: pbytes + lock: SysLock + cond: SysCond + elemType: PNimType + ready: bool + region: MemRegion + PRawChannel = ptr RawChannel + LoadStoreMode = enum mStore, mLoad Channel* {.gcsafe.}[TMsg] = RawChannel ## a channel for thread communication {.deprecated: [TRawChannel: RawChannel, TLoadStoreMode: LoadStoreMode, TChannel: Channel].} -const ChannelDeadMask = -2 - -proc initRawChannel(p: pointer) = - var c = cast[PRawChannel](p) - initSysLock(c.lock) - initSysCond(c.cond) - c.mask = -1 - -proc deinitRawChannel(p: pointer) = - var c = cast[PRawChannel](p) - # we need to grab the lock to be safe against sending threads! - acquireSys(c.lock) - c.mask = ChannelDeadMask - deallocOsPages(c.region) - deinitSys(c.lock) - deinitSysCond(c.cond) - -proc storeAux(dest, src: pointer, mt: PNimType, t: PRawChannel, - mode: LoadStoreMode) {.benign.} -proc storeAux(dest, src: pointer, n: ptr TNimNode, t: PRawChannel, - mode: LoadStoreMode) {.benign.} = - var - d = cast[ByteAddress](dest) - s = cast[ByteAddress](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, "storeAux") - -proc storeAux(dest, src: pointer, mt: PNimType, t: PRawChannel, - mode: LoadStoreMode) = - var - d = cast[ByteAddress](dest) - s = cast[ByteAddress](src) - sysAssert(mt != nil, "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](alloc(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))) - dealloc(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, "dest == nil") - if mode == mStore: - x[] = alloc(t.region, seq.len *% mt.base.size +% GenericSeqSize) - else: - unsureAsgnRef(x, newObj(mt, seq.len * mt.base.size + GenericSeqSize)) - var dst = cast[ByteAddress](cast[PPointer](dest)[]) - for i in 0..seq.len-1: - storeAux( - cast[pointer](dst +% i*% mt.base.size +% GenericSeqSize), - cast[pointer](cast[ByteAddress](s2) +% i *% mt.base.size +% - GenericSeqSize), - mt.base, t, mode) - var dstseq = cast[PGenericSeq](dst) - dstseq.len = seq.len - dstseq.reserved = seq.len - if mode != mStore: dealloc(t.region, s2) - of tyObject: - # copy type field: - var pint = cast[ptr PNimType](dest) - # XXX use dynamic type here! - pint[] = mt - if mt.base != nil: - storeAux(dest, src, mt.base, t, mode) - storeAux(dest, src, mt.node, t, mode) - of tyTuple: - 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[] = alloc(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, mt.base.size) - unsureAsgnRef(x, obj) - storeAux(x[], s, mt.base, t, mode) - if mode != mStore: dealloc(t.region, s) - else: - copyMem(dest, src, mt.size) # copy raw bits - -proc rawSend(q: PRawChannel, 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 capacity for 2 entries in the queue: - if cap == 0: cap = 1 - var n = cast[pbytes](alloc0(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: dealloc(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: PRawChannel, data: pointer, typ: PNimType) = - sysAssert q.count > 0, "rawRecv" - dec q.count - storeAux(data, addr(q.data[q.rd * typ.size]), typ, q, mLoad) - q.rd = (q.rd + 1) and q.mask - -template lockChannel(q: expr, action: stmt) {.immediate.} = - acquireSys(q.lock) - action - releaseSys(q.lock) - -template sendImpl(q: expr) {.immediate.} = - if q.mask == ChannelDeadMask: - sysFatal(DeadThreadError, "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 send*[TMsg](c: var Channel[TMsg], msg: TMsg) = - ## sends a message to a thread. `msg` is deeply copied. - var q = cast[PRawChannel](addr(c)) - sendImpl(q) - -proc llRecv(q: PRawChannel, res: pointer, typ: PNimType) = - # to save space, the generic is as small as possible - q.ready = true - while q.count <= 0: - waitSysCond(q.cond, q.lock) - q.ready = false - if typ != q.elemType: - releaseSys(q.lock) - sysFatal(ValueError, "cannot receive message of wrong type") - rawRecv(q, res, typ) - -proc recv*[TMsg](c: var Channel[TMsg]): TMsg = - ## receives a message from the channel `c`. This blocks until - ## a message has arrived! You may use ``peek`` to avoid the blocking. - var q = cast[PRawChannel](addr(c)) - acquireSys(q.lock) - llRecv(q, addr(result), cast[PNimType](getTypeInfo(result))) - releaseSys(q.lock) - -proc tryRecv*[TMsg](c: var Channel[TMsg]): tuple[dataAvailable: bool, - msg: TMsg] = - ## try to receives a message from the channel `c` if available. Otherwise - ## it returns ``(false, default(msg))``. - var q = cast[PRawChannel](addr(c)) - if q.mask != ChannelDeadMask: +const ChannelDeadMask = -2 + +proc initRawChannel(p: pointer) = + var c = cast[PRawChannel](p) + initSysLock(c.lock) + initSysCond(c.cond) + c.mask = -1 + +proc deinitRawChannel(p: pointer) = + var c = cast[PRawChannel](p) + # we need to grab the lock to be safe against sending threads! + acquireSys(c.lock) + c.mask = ChannelDeadMask + deallocOsPages(c.region) + deinitSys(c.lock) + deinitSysCond(c.cond) + +proc storeAux(dest, src: pointer, mt: PNimType, t: PRawChannel, + mode: LoadStoreMode) {.benign.} +proc storeAux(dest, src: pointer, n: ptr TNimNode, t: PRawChannel, + mode: LoadStoreMode) {.benign.} = + var + d = cast[ByteAddress](dest) + s = cast[ByteAddress](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, "storeAux") + +proc storeAux(dest, src: pointer, mt: PNimType, t: PRawChannel, + mode: LoadStoreMode) = + var + d = cast[ByteAddress](dest) + s = cast[ByteAddress](src) + sysAssert(mt != nil, "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](alloc(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))) + dealloc(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, "dest == nil") + if mode == mStore: + x[] = alloc(t.region, seq.len *% mt.base.size +% GenericSeqSize) + else: + unsureAsgnRef(x, newObj(mt, seq.len * mt.base.size + GenericSeqSize)) + var dst = cast[ByteAddress](cast[PPointer](dest)[]) + for i in 0..seq.len-1: + storeAux( + cast[pointer](dst +% i*% mt.base.size +% GenericSeqSize), + cast[pointer](cast[ByteAddress](s2) +% i *% mt.base.size +% + GenericSeqSize), + mt.base, t, mode) + var dstseq = cast[PGenericSeq](dst) + dstseq.len = seq.len + dstseq.reserved = seq.len + if mode != mStore: dealloc(t.region, s2) + of tyObject: + # copy type field: + var pint = cast[ptr PNimType](dest) + # XXX use dynamic type here! + pint[] = mt + if mt.base != nil: + storeAux(dest, src, mt.base, t, mode) + storeAux(dest, src, mt.node, t, mode) + of tyTuple: + 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[] = alloc(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, mt.base.size) + unsureAsgnRef(x, obj) + storeAux(x[], s, mt.base, t, mode) + if mode != mStore: dealloc(t.region, s) + else: + copyMem(dest, src, mt.size) # copy raw bits + +proc rawSend(q: PRawChannel, 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 capacity for 2 entries in the queue: + if cap == 0: cap = 1 + var n = cast[pbytes](alloc0(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: dealloc(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: PRawChannel, data: pointer, typ: PNimType) = + sysAssert q.count > 0, "rawRecv" + dec q.count + storeAux(data, addr(q.data[q.rd * typ.size]), typ, q, mLoad) + q.rd = (q.rd + 1) and q.mask + +template lockChannel(q: expr, action: stmt) {.immediate.} = + acquireSys(q.lock) + action + releaseSys(q.lock) + +template sendImpl(q: expr) {.immediate.} = + if q.mask == ChannelDeadMask: + sysFatal(DeadThreadError, "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 send*[TMsg](c: var Channel[TMsg], msg: TMsg) = + ## sends a message to a thread. `msg` is deeply copied. + var q = cast[PRawChannel](addr(c)) + sendImpl(q) + +proc llRecv(q: PRawChannel, res: pointer, typ: PNimType) = + # to save space, the generic is as small as possible + q.ready = true + while q.count <= 0: + waitSysCond(q.cond, q.lock) + q.ready = false + if typ != q.elemType: + releaseSys(q.lock) + sysFatal(ValueError, "cannot receive message of wrong type") + rawRecv(q, res, typ) + +proc recv*[TMsg](c: var Channel[TMsg]): TMsg = + ## receives a message from the channel `c`. This blocks until + ## a message has arrived! You may use ``peek`` to avoid the blocking. + var q = cast[PRawChannel](addr(c)) + acquireSys(q.lock) + llRecv(q, addr(result), cast[PNimType](getTypeInfo(result))) + releaseSys(q.lock) + +proc tryRecv*[TMsg](c: var Channel[TMsg]): tuple[dataAvailable: bool, + msg: TMsg] = + ## try to receives a message from the channel `c` if available. Otherwise + ## it returns ``(false, default(msg))``. + var q = cast[PRawChannel](addr(c)) + if q.mask != ChannelDeadMask: if tryAcquireSys(q.lock): - if q.count > 0: - llRecv(q, addr(result.msg), cast[PNimType](getTypeInfo(result.msg))) - result.dataAvailable = true - releaseSys(q.lock) - -proc peek*[TMsg](c: var Channel[TMsg]): int = - ## returns the current number of messages in the channel `c`. Returns -1 - ## if the channel has been closed. **Note**: This is dangerous to use - ## as it encourages races. It's much better to use ``tryRecv`` instead. - var q = cast[PRawChannel](addr(c)) - if q.mask != ChannelDeadMask: - lockChannel(q): - result = q.count - else: - result = -1 - -proc open*[TMsg](c: var Channel[TMsg]) = - ## opens a channel `c` for inter thread communication. - initRawChannel(addr(c)) - -proc close*[TMsg](c: var Channel[TMsg]) = - ## closes a channel `c` and frees its associated resources. - deinitRawChannel(addr(c)) - -proc ready*[TMsg](c: var Channel[TMsg]): bool = - ## returns true iff some thread is waiting on the channel `c` for - ## new messages. - var q = cast[PRawChannel](addr(c)) - result = q.ready - + if q.count > 0: + llRecv(q, addr(result.msg), cast[PNimType](getTypeInfo(result.msg))) + result.dataAvailable = true + releaseSys(q.lock) + +proc peek*[TMsg](c: var Channel[TMsg]): int = + ## returns the current number of messages in the channel `c`. Returns -1 + ## if the channel has been closed. **Note**: This is dangerous to use + ## as it encourages races. It's much better to use ``tryRecv`` instead. + var q = cast[PRawChannel](addr(c)) + if q.mask != ChannelDeadMask: + lockChannel(q): + result = q.count + else: + result = -1 + +proc open*[TMsg](c: var Channel[TMsg]) = + ## opens a channel `c` for inter thread communication. + initRawChannel(addr(c)) + +proc close*[TMsg](c: var Channel[TMsg]) = + ## closes a channel `c` and frees its associated resources. + deinitRawChannel(addr(c)) + +proc ready*[TMsg](c: var Channel[TMsg]): bool = + ## returns true iff some thread is waiting on the channel `c` for + ## new messages. + var q = cast[PRawChannel](addr(c)) + result = q.ready + |