| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| #include "runtime.h" |
| #include "type.h" |
| #include "malloc.h" |
| |
| static void |
| printiface(Iface i) |
| { |
| printf("(%p,%p)", i.tab, i.data); |
| } |
| |
| static void |
| printeface(Eface e) |
| { |
| printf("(%p,%p)", e.type, e.data); |
| } |
| |
| /* |
| * layout of Itab known to compilers |
| */ |
| struct Itab |
| { |
| InterfaceType* inter; |
| Type* type; |
| Itab* link; |
| int32 bad; |
| int32 unused; |
| void (*fun[])(void); |
| }; |
| |
| static Itab* hash[1009]; |
| static Lock ifacelock; |
| |
| static Itab* |
| itab(InterfaceType *inter, Type *type, int32 canfail) |
| { |
| int32 locked; |
| int32 ni; |
| Method *t, *et; |
| IMethod *i, *ei; |
| uint32 h; |
| String *iname; |
| Itab *m; |
| UncommonType *x; |
| Type *itype; |
| |
| if(inter->mhdr.len == 0) |
| throw("internal error - misuse of itab"); |
| |
| // easy case |
| x = type->x; |
| if(x == nil) { |
| if(canfail) |
| return nil; |
| iname = inter->m[0].name; |
| goto throw; |
| } |
| |
| // compiler has provided some good hash codes for us. |
| h = inter->hash; |
| h += 17 * type->hash; |
| // TODO(rsc): h += 23 * x->mhash ? |
| h %= nelem(hash); |
| |
| // look twice - once without lock, once with. |
| // common case will be no lock contention. |
| for(locked=0; locked<2; locked++) { |
| if(locked) |
| lock(&ifacelock); |
| for(m=hash[h]; m!=nil; m=m->link) { |
| if(m->inter == inter && m->type == type) { |
| if(m->bad) { |
| m = nil; |
| if(!canfail) { |
| // this can only happen if the conversion |
| // was already done once using the , ok form |
| // and we have a cached negative result. |
| // the cached result doesn't record which |
| // interface function was missing, so jump |
| // down to the interface check, which will |
| // do more work but give a better error. |
| goto search; |
| } |
| } |
| if(locked) |
| unlock(&ifacelock); |
| return m; |
| } |
| } |
| } |
| |
| ni = inter->mhdr.len; |
| m = malloc(sizeof(*m) + ni*sizeof m->fun[0]); |
| m->inter = inter; |
| m->type = type; |
| |
| search: |
| // both inter and type have method sorted by name, |
| // and interface names are unique, |
| // so can iterate over both in lock step; |
| // the loop is O(ni+nt) not O(ni*nt). |
| i = inter->m; |
| ei = i + inter->mhdr.len; |
| t = x->m; |
| et = t + x->mhdr.len; |
| for(; i < ei; i++) { |
| itype = i->type; |
| iname = i->name; |
| for(;; t++) { |
| if(t >= et) { |
| if(!canfail) { |
| throw: |
| // didn't find method |
| printf("%S is not %S: missing method %S\n", |
| *type->string, *inter->string, *iname); |
| throw("interface conversion"); |
| return nil; // not reached |
| } |
| m->bad = 1; |
| goto out; |
| } |
| if(t->mtyp == itype && t->name == iname) |
| break; |
| } |
| if(m) |
| m->fun[i - inter->m] = t->ifn; |
| } |
| |
| out: |
| m->link = hash[h]; |
| hash[h] = m; |
| if(locked) |
| unlock(&ifacelock); |
| if(m->bad) |
| return nil; |
| return m; |
| } |
| |
| static void |
| copyin(Type *t, void *src, void **dst) |
| { |
| int32 wid, alg; |
| void *p; |
| |
| wid = t->size; |
| alg = t->alg; |
| |
| if(wid <= sizeof(*dst)) |
| algarray[alg].copy(wid, dst, src); |
| else { |
| p = mal(wid); |
| algarray[alg].copy(wid, p, src); |
| *dst = p; |
| } |
| } |
| |
| static void |
| copyout(Type *t, void **src, void *dst) |
| { |
| int32 wid, alg; |
| |
| wid = t->size; |
| alg = t->alg; |
| |
| if(wid <= sizeof(*src)) |
| algarray[alg].copy(wid, dst, src); |
| else |
| algarray[alg].copy(wid, dst, *src); |
| } |
| |
| // ifaceT2I(sigi *byte, sigt *byte, elem any) (ret Iface); |
| #pragma textflag 7 |
| void |
| ·ifaceT2I(InterfaceType *inter, Type *t, ...) |
| { |
| byte *elem; |
| Iface *ret; |
| int32 wid; |
| |
| elem = (byte*)(&t+1); |
| wid = t->size; |
| ret = (Iface*)(elem + rnd(wid, Structrnd)); |
| ret->tab = itab(inter, t, 0); |
| copyin(t, elem, &ret->data); |
| } |
| |
| // ifaceT2E(sigt *byte, elem any) (ret Eface); |
| #pragma textflag 7 |
| void |
| ·ifaceT2E(Type *t, ...) |
| { |
| byte *elem; |
| Eface *ret; |
| int32 wid; |
| |
| elem = (byte*)(&t+1); |
| wid = t->size; |
| ret = (Eface*)(elem + rnd(wid, Structrnd)); |
| |
| ret->type = t; |
| copyin(t, elem, &ret->data); |
| } |
| |
| // ifaceI2T(sigt *byte, iface any) (ret any); |
| #pragma textflag 7 |
| void |
| ·ifaceI2T(Type *t, Iface i, ...) |
| { |
| Itab *tab; |
| byte *ret; |
| |
| ret = (byte*)(&i+1); |
| tab = i.tab; |
| if(tab == nil) { |
| printf("interface is nil, not %S\n", *t->string); |
| throw("interface conversion"); |
| } |
| if(tab->type != t) { |
| printf("%S is %S, not %S\n", *tab->inter->string, *tab->type->string, *t->string); |
| throw("interface conversion"); |
| } |
| copyout(t, &i.data, ret); |
| } |
| |
| // ifaceI2T2(sigt *byte, i Iface) (ret any, ok bool); |
| #pragma textflag 7 |
| void |
| ·ifaceI2T2(Type *t, Iface i, ...) |
| { |
| byte *ret; |
| bool *ok; |
| int32 wid; |
| |
| ret = (byte*)(&i+1); |
| wid = t->size; |
| ok = (bool*)(ret+rnd(wid, 1)); |
| |
| if(i.tab == nil || i.tab->type != t) { |
| *ok = false; |
| ·memclr(ret, wid); |
| return; |
| } |
| |
| *ok = true; |
| copyout(t, &i.data, ret); |
| } |
| |
| // ifaceE2T(sigt *byte, e Eface) (ret any); |
| #pragma textflag 7 |
| void |
| ·ifaceE2T(Type *t, Eface e, ...) |
| { |
| byte *ret; |
| |
| ret = (byte*)(&e+1); |
| |
| if(e.type != t) { |
| if(e.type == nil) |
| printf("interface is nil, not %S\n", *t->string); |
| else |
| printf("interface is %S, not %S\n", *e.type->string, *t->string); |
| throw("interface conversion"); |
| } |
| copyout(t, &e.data, ret); |
| } |
| |
| // ifaceE2T2(sigt *byte, iface any) (ret any, ok bool); |
| #pragma textflag 7 |
| void |
| ·ifaceE2T2(Type *t, Eface e, ...) |
| { |
| byte *ret; |
| bool *ok; |
| int32 wid; |
| |
| ret = (byte*)(&e+1); |
| wid = t->size; |
| ok = (bool*)(ret+rnd(wid, 1)); |
| |
| if(t != e.type) { |
| *ok = false; |
| ·memclr(ret, wid); |
| return; |
| } |
| |
| *ok = true; |
| copyout(t, &e.data, ret); |
| } |
| |
| // ifaceI2E(sigi *byte, iface any) (ret any); |
| // TODO(rsc): Move to back end, throw away function. |
| void |
| ·ifaceI2E(Iface i, Eface ret) |
| { |
| Itab *tab; |
| |
| ret.data = i.data; |
| tab = i.tab; |
| if(tab == nil) |
| ret.type = nil; |
| else |
| ret.type = tab->type; |
| FLUSH(&ret); |
| } |
| |
| // ifaceI2I(sigi *byte, iface any) (ret any); |
| // called only for implicit (no type assertion) conversions. |
| // converting nil is okay. |
| void |
| ·ifaceI2I(InterfaceType *inter, Iface i, Iface ret) |
| { |
| Itab *tab; |
| |
| tab = i.tab; |
| if(tab == nil) { |
| // If incoming interface is uninitialized (zeroed) |
| // make the outgoing interface zeroed as well. |
| ret.tab = nil; |
| ret.data = nil; |
| } else { |
| ret = i; |
| if(tab->inter != inter) |
| ret.tab = itab(inter, tab->type, 0); |
| } |
| |
| FLUSH(&ret); |
| } |
| |
| // ifaceI2Ix(sigi *byte, iface any) (ret any); |
| // called only for explicit conversions (with type assertion). |
| // converting nil is not okay. |
| void |
| ·ifaceI2Ix(InterfaceType *inter, Iface i, Iface ret) |
| { |
| Itab *tab; |
| |
| tab = i.tab; |
| if(tab == nil) { |
| // explicit conversions require non-nil interface value. |
| printf("interface is nil, not %S\n", *inter->string); |
| throw("interface conversion"); |
| } else { |
| ret = i; |
| if(tab->inter != inter) |
| ret.tab = itab(inter, tab->type, 0); |
| } |
| |
| FLUSH(&ret); |
| } |
| |
| // ifaceI2I2(sigi *byte, iface any) (ret any, ok bool); |
| void |
| ·ifaceI2I2(InterfaceType *inter, Iface i, Iface ret, bool ok) |
| { |
| Itab *tab; |
| |
| tab = i.tab; |
| if(tab == nil) { |
| // If incoming interface is nil, the conversion fails. |
| ret.tab = nil; |
| ret.data = nil; |
| ok = false; |
| } else { |
| ret = i; |
| ok = true; |
| if(tab->inter != inter) { |
| ret.tab = itab(inter, tab->type, 1); |
| if(ret.tab == nil) { |
| ret.data = nil; |
| ok = false; |
| } |
| } |
| } |
| |
| FLUSH(&ret); |
| FLUSH(&ok); |
| } |
| |
| // ifaceE2I(sigi *byte, iface any) (ret any); |
| // Called only for explicit conversions (with type assertion). |
| void |
| ifaceE2I(InterfaceType *inter, Eface e, Iface *ret) |
| { |
| Type *t; |
| |
| t = e.type; |
| if(t == nil) { |
| // explicit conversions require non-nil interface value. |
| printf("interface is nil, not %S\n", *inter->string); |
| throw("interface conversion"); |
| } else { |
| ret->data = e.data; |
| ret->tab = itab(inter, t, 0); |
| } |
| } |
| |
| // ifaceE2I(sigi *byte, iface any) (ret any); |
| // Called only for explicit conversions (with type assertion). |
| void |
| ·ifaceE2I(InterfaceType *inter, Eface e, Iface ret) |
| { |
| ifaceE2I(inter, e, &ret); |
| } |
| |
| // ifaceE2I2(sigi *byte, iface any) (ret any, ok bool); |
| void |
| ·ifaceE2I2(InterfaceType *inter, Eface e, Iface ret, bool ok) |
| { |
| Type *t; |
| |
| t = e.type; |
| ok = true; |
| if(t == nil) { |
| // If incoming interface is nil, the conversion fails. |
| ret.data = nil; |
| ret.tab = nil; |
| ok = false; |
| } else { |
| ret.data = e.data; |
| ret.tab = itab(inter, t, 1); |
| if(ret.tab == nil) { |
| ret.data = nil; |
| ok = false; |
| } |
| } |
| FLUSH(&ret); |
| FLUSH(&ok); |
| } |
| |
| static uintptr |
| ifacehash1(void *data, Type *t) |
| { |
| int32 alg, wid; |
| |
| if(t == nil) |
| return 0; |
| |
| alg = t->alg; |
| wid = t->size; |
| if(algarray[alg].hash == nohash) { |
| // calling nohash will throw too, |
| // but we can print a better error. |
| printf("hash of unhashable type %S\n", *t->string); |
| if(alg == AFAKE) |
| throw("fake interface hash"); |
| throw("interface hash"); |
| } |
| if(wid <= sizeof(data)) |
| return algarray[alg].hash(wid, &data); |
| return algarray[alg].hash(wid, data); |
| } |
| |
| uintptr |
| ifacehash(Iface a) |
| { |
| if(a.tab == nil) |
| return 0; |
| return ifacehash1(a.data, a.tab->type); |
| } |
| |
| uintptr |
| efacehash(Eface a) |
| { |
| return ifacehash1(a.data, a.type); |
| } |
| |
| static bool |
| ifaceeq1(void *data1, void *data2, Type *t) |
| { |
| int32 alg, wid; |
| |
| alg = t->alg; |
| wid = t->size; |
| |
| if(algarray[alg].equal == noequal) { |
| // calling noequal will throw too, |
| // but we can print a better error. |
| printf("comparing uncomparable type %S\n", *t->string); |
| if(alg == AFAKE) |
| throw("fake interface compare"); |
| throw("interface compare"); |
| } |
| |
| if(wid <= sizeof(data1)) |
| return algarray[alg].equal(wid, &data1, &data2); |
| return algarray[alg].equal(wid, data1, data2); |
| } |
| |
| bool |
| ifaceeq(Iface i1, Iface i2) |
| { |
| if(i1.tab != i2.tab) |
| return false; |
| if(i1.tab == nil) |
| return true; |
| return ifaceeq1(i1.data, i2.data, i1.tab->type); |
| } |
| |
| bool |
| efaceeq(Eface e1, Eface e2) |
| { |
| if(e1.type != e2.type) |
| return false; |
| if(e1.type == nil) |
| return true; |
| return ifaceeq1(e1.data, e2.data, e1.type); |
| } |
| |
| // ifaceeq(i1 any, i2 any) (ret bool); |
| void |
| ·ifaceeq(Iface i1, Iface i2, bool ret) |
| { |
| ret = ifaceeq(i1, i2); |
| FLUSH(&ret); |
| } |
| |
| // efaceeq(i1 any, i2 any) (ret bool) |
| void |
| ·efaceeq(Eface e1, Eface e2, bool ret) |
| { |
| ret = efaceeq(e1, e2); |
| FLUSH(&ret); |
| } |
| |
| // ifacethash(i1 any) (ret uint32); |
| void |
| ·ifacethash(Iface i1, uint32 ret) |
| { |
| Itab *tab; |
| |
| ret = 0; |
| tab = i1.tab; |
| if(tab != nil) |
| ret = tab->type->hash; |
| FLUSH(&ret); |
| } |
| |
| // efacethash(e1 any) (ret uint32) |
| void |
| ·efacethash(Eface e1, uint32 ret) |
| { |
| Type *t; |
| |
| ret = 0; |
| t = e1.type; |
| if(t != nil) |
| ret = t->hash; |
| FLUSH(&ret); |
| } |
| |
| void |
| ·printiface(Iface i) |
| { |
| printiface(i); |
| } |
| |
| void |
| ·printeface(Eface e) |
| { |
| printeface(e); |
| } |
| |
| void |
| unsafe·Typeof(Eface e, Eface ret) |
| { |
| if(e.type == nil) { |
| ret.type = nil; |
| ret.data = nil; |
| } else |
| ret = *(Eface*)e.type; |
| FLUSH(&ret); |
| } |
| |
| void |
| unsafe·Reflect(Eface e, Eface rettype, void *retaddr) |
| { |
| uintptr *p; |
| uintptr x; |
| |
| if(e.type == nil) { |
| rettype.type = nil; |
| rettype.data = nil; |
| retaddr = 0; |
| } else { |
| rettype = *(Eface*)e.type; |
| if(e.type->size <= sizeof(uintptr)) { |
| // Copy data into x ... |
| x = 0; |
| algarray[e.type->alg].copy(e.type->size, &x, &e.data); |
| |
| // but then build pointer to x so that Reflect |
| // always returns pointer to data. |
| p = mal(sizeof(uintptr)); |
| *p = x; |
| } else { |
| // Already a pointer, but still make a copy, |
| // to preserve value semantics for interface data. |
| p = mal(e.type->size); |
| algarray[e.type->alg].copy(e.type->size, p, e.data); |
| } |
| retaddr = p; |
| } |
| FLUSH(&rettype); |
| FLUSH(&retaddr); |
| } |
| |
| void |
| unsafe·Unreflect(Eface typ, void *addr, Eface e) |
| { |
| // Reflect library has reinterpreted typ |
| // as its own kind of type structure. |
| // We know that the pointer to the original |
| // type structure sits before the data pointer. |
| e.type = (Type*)((Eface*)typ.data-1); |
| |
| // Interface holds either pointer to data |
| // or copy of original data. |
| if(e.type->size <= sizeof(uintptr)) |
| algarray[e.type->alg].copy(e.type->size, &e.data, addr); |
| else { |
| // Easier: already a pointer to data. |
| // TODO(rsc): Should this make a copy? |
| e.data = addr; |
| } |
| |
| FLUSH(&e); |
| } |
| |
| void |
| unsafe·New(Eface typ, void *ret) |
| { |
| Type *t; |
| |
| // Reflect library has reinterpreted typ |
| // as its own kind of type structure. |
| // We know that the pointer to the original |
| // type structure sits before the data pointer. |
| t = (Type*)((Eface*)typ.data-1); |
| |
| if(t->kind&KindNoPointers) |
| ret = mallocgc(t->size, RefNoPointers, 1, 1); |
| else |
| ret = mal(t->size); |
| FLUSH(&ret); |
| } |
| |
| void |
| unsafe·NewArray(Eface typ, uint32 n, void *ret) |
| { |
| uint64 size; |
| Type *t; |
| |
| // Reflect library has reinterpreted typ |
| // as its own kind of type structure. |
| // We know that the pointer to the original |
| // type structure sits before the data pointer. |
| t = (Type*)((Eface*)typ.data-1); |
| |
| size = n*t->size; |
| if(t->kind&KindNoPointers) |
| ret = mallocgc(size, RefNoPointers, 1, 1); |
| else |
| ret = mal(size); |
| FLUSH(&ret); |
| } |