/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- * vim: set ts=8 sw=4 et tw=99: * * ***** BEGIN LICENSE BLOCK ***** * Version: MPL 1.1/GPL 2.0/LGPL 2.1 * * The contents of this file are subject to the Mozilla Public License Version * 1.1 (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * http://www.mozilla.org/MPL/ * * Software distributed under the License is distributed on an "AS IS" basis, * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License * for the specific language governing rights and limitations under the * License. * * The Original Code is Mozilla Communicator client code, released * March 31, 1998. * * The Initial Developer of the Original Code is * Netscape Communications Corporation. * Portions created by the Initial Developer are Copyright (C) 1998 * the Initial Developer. All Rights Reserved. * * Contributor(s): * * Alternatively, the contents of this file may be used under the terms of * either of the GNU General Public License Version 2 or later (the "GPL"), * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), * in which case the provisions of the GPL or the LGPL are applicable instead * of those above. If you wish to allow use of your version of this file only * under the terms of either the GPL or the LGPL, and not to allow others to * use your version of this file under the terms of the MPL, indicate your * decision by deleting the provisions above and replace them with the notice * and other provisions required by the GPL or the LGPL. If you do not delete * the provisions above, a recipient may use your version of this file under * the terms of any one of the MPL, the GPL or the LGPL. * * ***** END LICENSE BLOCK ***** */ #ifndef jsscope_h___ #define jsscope_h___ /* * JS symbol tables. */ #include "jstypes.h" #include "jslock.h" #include "jsfun.h" #include "jsobj.h" #include "jsprvtd.h" #include "jspubtd.h" #ifdef _MSC_VER #pragma warning(push) #pragma warning(disable:4800) #endif JS_BEGIN_EXTERN_C /* * Given P independent, non-unique properties each of size S words mapped by * all scopes in a runtime, construct a property tree of N nodes each of size * S+L words (L for tree linkage). A nominal L value is 2 for leftmost-child * and right-sibling links. We hope that the N < P by enough that the space * overhead of L, and the overhead of scope entries pointing at property tree * nodes, is worth it. * * The tree construction goes as follows. If any empty scope in the runtime * has a property X added to it, find or create a node under the tree root * labeled X, and set scope->lastProp to point at that node. If any non-empty * scope whose most recently added property is labeled Y has another property * labeled Z added, find or create a node for Z under the node that was added * for Y, and set scope->lastProp to point at that node. * * A property is labeled by its members' values: id, getter, setter, slot, * attributes, tiny or short id, and a field telling for..in order. Note that * labels are not unique in the tree, but they are unique among a node's kids * (barring rare and benign multi-threaded race condition outcomes, see below) * and along any ancestor line from the tree root to a given leaf node (except * for the hard case of duplicate formal parameters to a function). * * Thus the root of the tree represents all empty scopes, and the first ply * of the tree represents all scopes containing one property, etc. Each node * in the tree can stand for any number of scopes having the same ordered set * of properties, where that node was the last added to the scope. (We need * not store the root of the tree as a node, and do not -- all we need are * links to its kids.) * * Sidebar on for..in loop order: ECMA requires no particular order, but this * implementation has promised and delivered property definition order, and * compatibility is king. We could use an order number per property, which * would require a sort in js_Enumerate, and an entry order generation number * per scope. An order number beats a list, which should be doubly-linked for * O(1) delete. An even better scheme is to use a parent link in the property * tree, so that the ancestor line can be iterated from scope->lastProp when * filling in a JSIdArray from back to front. This parent link also helps the * GC to sweep properties iteratively. * * What if a property Y is deleted from a scope? If Y is the last property in * the scope, we simply adjust the scope's lastProp member after we remove the * scope's hash-table entry pointing at that property node. The parent link * mentioned in the for..in sidebar above makes this adjustment O(1). But if * Y comes between X and Z in the scope, then we might have to "fork" the tree * at X, leaving X->Y->Z in case other scopes have those properties added in * that order; and to finish the fork, we'd add a node labeled Z with the path * X->Z, if it doesn't exist. This could lead to lots of extra nodes, and to * O(n^2) growth when deleting lots of properties. * * Rather, for O(1) growth all around, we should share the path X->Y->Z among * scopes having those three properties added in that order, and among scopes * having only X->Z where Y was deleted. All such scopes have a lastProp that * points to the Z child of Y. But a scope in which Y was deleted does not * have a table entry for Y, and when iterating that scope by traversing the * ancestor line from Z, we will have to test for a table entry for each node, * skipping nodes that lack entries. * * What if we add Y again? X->Y->Z->Y is wrong and we'll enumerate Y twice. * Therefore we must fork in such a case, if not earlier. Because delete is * "bursty", we should not fork eagerly. Delaying a fork till we are at risk * of adding Y after it was deleted already requires a flag in the JSScope, to * wit, SCOPE_MIDDLE_DELETE. * * What about thread safety? If the property tree operations done by requests * are find-node and insert-node, then the only hazard is duplicate insertion. * This is harmless except for minor bloat. When all requests have ended or * been suspended, the GC is free to sweep the tree after marking all nodes * reachable from scopes, performing remove-node operations as needed. * * Is the property tree worth it compared to property storage in each table's * entries? To decide, we must find the relation <> between the words used * with a property tree and the words required without a tree. * * Model all scopes as one super-scope of capacity T entries (T a power of 2). * Let alpha be the load factor of this double hash-table. With the property * tree, each entry in the table is a word-sized pointer to a node that can be * shared by many scopes. But all such pointers are overhead compared to the * situation without the property tree, where the table stores property nodes * directly, as entries each of size S words. With the property tree, we need * L=2 extra words per node for siblings and kids pointers. Without the tree, * (1-alpha)*S*T words are wasted on free or removed sentinel-entries required * by double hashing. * * Therefore, * * (property tree) <> (no property tree) * N*(S+L) + T <> S*T * N*(S+L) + T <> P*S + (1-alpha)*S*T * N*(S+L) + alpha*T + (1-alpha)*T <> P*S + (1-alpha)*S*T * * Note that P is alpha*T by definition, so * * N*(S+L) + P + (1-alpha)*T <> P*S + (1-alpha)*S*T * N*(S+L) <> P*S - P + (1-alpha)*S*T - (1-alpha)*T * N*(S+L) <> (P + (1-alpha)*T) * (S-1) * N*(S+L) <> (P + (1-alpha)*P/alpha) * (S-1) * N*(S+L) <> P * (1/alpha) * (S-1) * * Let N = P*beta for a compression ratio beta, beta <= 1: * * P*beta*(S+L) <> P * (1/alpha) * (S-1) * beta*(S+L) <> (S-1)/alpha * beta <> (S-1)/((S+L)*alpha) * * For S = 6 (32-bit architectures) and L = 2, the property tree wins iff * * beta < 5/(8*alpha) * * We ensure that alpha <= .75, so the property tree wins if beta < .83_. An * average beta from recent Mozilla browser startups was around .6. * * Can we reduce L? Observe that the property tree degenerates into a list of * lists if at most one property Y follows X in all scopes. In or near such a * case, we waste a word on the right-sibling link outside of the root ply of * the tree. Note also that the root ply tends to be large, so O(n^2) growth * searching it is likely, indicating the need for hashing (but with increased * thread safety costs). * * If only K out of N nodes in the property tree have more than one child, we * could eliminate the sibling link and overlay a children list or hash-table * pointer on the leftmost-child link (which would then be either null or an * only-child link; the overlay could be tagged in the low bit of the pointer, * or flagged elsewhere in the property tree node, although such a flag must * not be considered when comparing node labels during tree search). * * For such a system, L = 1 + (K * averageChildrenTableSize) / N instead of 2. * If K << N, L approaches 1 and the property tree wins if beta < .95. * * We observe that fan-out below the root ply of the property tree appears to * have extremely low degree (see the MeterPropertyTree code that histograms * child-counts in jsscope.c), so instead of a hash-table we use a linked list * of child node pointer arrays ("kid chunks"). The details are isolated in * jsscope.c; others must treat JSScopeProperty.kids as opaque. We leave it * strongly typed for debug-ability of the common (null or one-kid) cases. * * One final twist (can you stand it?): the mean number of entries per scope * in Mozilla is < 5, with a large standard deviation (~8). Instead of always * allocating scope->table, we leave it null while initializing all the other * scope members as if it were non-null and minimal-length. Until a property * is added that crosses the threshold of 6 or more entries for hashing, or * until a "middle delete" occurs, we use linear search from scope->lastProp * to find a given id, and save on the space overhead of a hash table. */ struct JSScope : public JSObjectMap { #ifdef JS_THREADSAFE JSTitle title; /* lock state */ #endif JSObject *object; /* object that owns this scope */ jsrefcount nrefs; /* count of all referencing objects */ uint32 freeslot; /* index of next free slot in object */ JSScope *emptyScope; /* cache for getEmptyScope below */ uint8 flags; /* flags, see below */ int8 hashShift; /* multiplicative hash shift */ uint16 spare; /* reserved */ uint32 entryCount; /* number of entries in table */ uint32 removedCount; /* removed entry sentinels in table */ JSScopeProperty **table; /* table of ptrs to shared tree nodes */ JSScopeProperty *lastProp; /* pointer to last property added */ private: void initMinimal(JSContext *cx, uint32 newShape); bool createTable(JSContext *cx, bool report); bool changeTable(JSContext *cx, int change); void reportReadOnlyScope(JSContext *cx); void generateOwnShape(JSContext *cx); JSScopeProperty **searchTable(jsid id, bool adding); inline JSScopeProperty **search(jsid id, bool adding); JSScope *createEmptyScope(JSContext *cx, JSClass *clasp); public: explicit JSScope(const JSObjectOps *ops, JSObject *obj = NULL) : JSObjectMap(ops, 0), object(obj) {} /* Create a mutable, owned, empty scope. */ static JSScope *create(JSContext *cx, const JSObjectOps *ops, JSClass *clasp, JSObject *obj, uint32 shape); static void destroy(JSContext *cx, JSScope *scope); /* * Return an immutable, shareable, empty scope with the same ops as this * and the same freeslot as this had when empty. * * If |this| is the scope of an object |proto|, the resulting scope can be * used as the scope of a new object whose prototype is |proto|. */ JSScope *getEmptyScope(JSContext *cx, JSClass *clasp) { if (emptyScope) { emptyScope->hold(); return emptyScope; } return createEmptyScope(cx, clasp); } bool getEmptyScopeShape(JSContext *cx, JSClass *clasp, uint32 *shapep) { if (emptyScope) { *shapep = emptyScope->shape; return true; } JSScope *e = getEmptyScope(cx, clasp); if (!e) return false; *shapep = e->shape; e->drop(cx, NULL); return true; } inline void hold(); inline bool drop(JSContext *cx, JSObject *obj); JSScopeProperty *lookup(jsid id); bool has(JSScopeProperty *sprop); JSScopeProperty *add(JSContext *cx, jsid id, JSPropertyOp getter, JSPropertyOp setter, uint32 slot, uintN attrs, uintN flags, intN shortid); JSScopeProperty *change(JSContext *cx, JSScopeProperty *sprop, uintN attrs, uintN mask, JSPropertyOp getter, JSPropertyOp setter); bool remove(JSContext *cx, jsid id); void clear(JSContext *cx); void extend(JSContext *cx, JSScopeProperty *sprop); /* * Read barrier to clone a joined function object stored as a method. * Defined inline further below. */ inline bool methodReadBarrier(JSContext *cx, JSScopeProperty *sprop, jsval *vp); /* * Write barrier to check for a method value change. Defined inline below * after methodReadBarrier. Two flavors to handle JSOP_*GVAR, which deals * in slots not sprops, while not deoptimizing to map slot to sprop unless * flags show this is necessary. The methodShapeChange overload (directly * below) parallels this. */ inline bool methodWriteBarrier(JSContext *cx, JSScopeProperty *sprop, jsval v); inline bool methodWriteBarrier(JSContext *cx, uint32 slot, jsval v); void trace(JSTracer *trc); void brandingShapeChange(JSContext *cx, uint32 slot, jsval v); void deletingShapeChange(JSContext *cx, JSScopeProperty *sprop); bool methodShapeChange(JSContext *cx, JSScopeProperty *sprop, jsval toval); bool methodShapeChange(JSContext *cx, uint32 slot, jsval toval); void protoShapeChange(JSContext *cx); void replacingShapeChange(JSContext *cx, JSScopeProperty *sprop, JSScopeProperty *newsprop); void sealingShapeChange(JSContext *cx); void shadowingShapeChange(JSContext *cx, JSScopeProperty *sprop); /* By definition, hashShift = JS_DHASH_BITS - log2(capacity). */ #define SCOPE_CAPACITY(scope) JS_BIT(JS_DHASH_BITS-(scope)->hashShift) enum { MIDDLE_DELETE = 0x0001, SEALED = 0x0002, BRANDED = 0x0004, INDEXED_PROPERTIES = 0x0008, OWN_SHAPE = 0x0010, METHOD_BARRIER = 0x0020, /* * This flag toggles with each shape-regenerating GC cycle. * See JSRuntime::gcRegenShapesScopeFlag. */ SHAPE_REGEN = 0x0040 }; bool hadMiddleDelete() { return flags & MIDDLE_DELETE; } void setMiddleDelete() { flags |= MIDDLE_DELETE; } void clearMiddleDelete() { flags &= ~MIDDLE_DELETE; } /* * Don't define clearSealed, as it can't be done safely because JS_LOCK_OBJ * will avoid taking the lock if the object owns its scope and the scope is * sealed. */ bool sealed() { return flags & SEALED; } void setSealed() { flags |= SEALED; } /* * A branded scope's object contains plain old methods (function-valued * properties without magic getters and setters), and its scope->shape * evolves whenever a function value changes. */ bool branded() { return flags & BRANDED; } void setBranded() { flags |= BRANDED; } bool hadIndexedProperties() { return flags & INDEXED_PROPERTIES; } void setIndexedProperties() { flags |= INDEXED_PROPERTIES; } bool hasOwnShape() { return flags & OWN_SHAPE; } void setOwnShape() { flags |= OWN_SHAPE; } bool hasRegenFlag(uint8 regenFlag) { return (flags & SHAPE_REGEN) == regenFlag; } /* * A scope has a method barrier when some compiler-created "null closure" * function objects (functions that do not use lexical bindings above their * scope, only free variable names) that have a correct JSSLOT_PARENT value * thanks to the COMPILE_N_GO optimization are stored as newly added direct * property values. * * The de-facto standard JS language requires each evaluation of such a * closure to result in a unique (according to === and observable effects) * function object. ES3 tried to allow implementations to "join" such * objects to a single compiler-created object, but this makes an overt * mutation hazard, also an "identity hazard" against interoperation among * implementations that join and do not join. * * To stay compatible with the de-facto standard, we store the compiler- * created function object as the method value, set the METHOD_BARRIER * flag, and brand the scope with a predictable shape that reflects its * method values, which are cached and traced without being loaded, based * on shape-qualified cache hit logic and equivalent trace guards. See * BRANDED above. * * This means scope->hasMethodBarrier() => scope->branded(), but of course * not the other way around. * * Then when reading from a scope for which scope->hasMethodBarrier() is * true, we count on the scope's qualified/guarded shape being unique and * add a read barrier that clones the compiler-created function object on * demand, reshaping the scope. * * This read barrier is bypassed when evaluating the callee sub-expression * of a call expression (see the JOF_CALLOP opcodes in jsopcode.tbl), since * such ops do not present an identity or mutation hazard. */ bool hasMethodBarrier() { return flags & METHOD_BARRIER; } void setMethodBarrier() { flags |= METHOD_BARRIER | BRANDED; } bool owned() { return object != NULL; } }; inline bool JS_IS_SCOPE_LOCKED(JSContext *cx, JSScope *scope) { return JS_IS_TITLE_LOCKED(cx, &scope->title); } inline JSScope * OBJ_SCOPE(JSObject *obj) { JS_ASSERT(OBJ_IS_NATIVE(obj)); return (JSScope *) obj->map; } inline uint32 OBJ_SHAPE(JSObject *obj) { JS_ASSERT(obj->map->shape != JSObjectMap::SHAPELESS); return obj->map->shape; } /* * A little information hiding for scope->lastProp, in case it ever becomes * a tagged pointer again. */ #define SCOPE_LAST_PROP(scope) \ (JS_ASSERT_IF((scope)->lastProp, !JSVAL_IS_NULL((scope)->lastProp->id)), \ (scope)->lastProp) #define SCOPE_REMOVE_LAST_PROP(scope) \ (JS_ASSERT_IF((scope)->lastProp->parent, \ !JSVAL_IS_NULL((scope)->lastProp->parent->id)), \ (scope)->lastProp = (scope)->lastProp->parent) /* * Helpers for reinterpreting JSPropertyOp as JSObject* for scripted getters * and setters. */ inline JSObject * js_CastAsObject(JSPropertyOp op) { return JS_FUNC_TO_DATA_PTR(JSObject *, op); } inline jsval js_CastAsObjectJSVal(JSPropertyOp op) { return OBJECT_TO_JSVAL(JS_FUNC_TO_DATA_PTR(JSObject *, op)); } inline JSPropertyOp js_CastAsPropertyOp(JSObject *object) { return JS_DATA_TO_FUNC_PTR(JSPropertyOp, object); } struct JSScopeProperty { jsid id; /* int-tagged jsval/untagged JSAtom* */ JSPropertyOp getter; /* getter and setter hooks or objects */ JSPropertyOp setter; /* getter is JSObject* and setter is 0 if sprop->isMethod() */ uint32 slot; /* abstract index in object slots */ uint8 attrs; /* attributes, see jsapi.h JSPROP_* */ uint8 flags; /* flags, see below for defines */ int16 shortid; /* tinyid, or local arg/var index */ JSScopeProperty *parent; /* parent node, reverse for..in order */ JSScopeProperty *kids; /* null, single child, or a tagged ptr to many-kids data structure */ uint32 shape; /* property cache shape identifier */ /* Bits stored in sprop->flags. */ #define SPROP_MARK 0x01 #define SPROP_IS_ALIAS 0x02 #define SPROP_HAS_SHORTID 0x04 #define SPROP_FLAG_SHAPE_REGEN 0x08 #define SPROP_IS_METHOD 0x10 bool isMethod() const { return flags & SPROP_IS_METHOD; } JSObject *methodObject() const { JS_ASSERT(isMethod()); return js_CastAsObject(getter); } jsval methodValue() const { JS_ASSERT(isMethod()); return js_CastAsObjectJSVal(getter); } bool hasGetterObject() const { return attrs & JSPROP_GETTER; } JSObject *getterObject() const { JS_ASSERT(hasGetterObject()); return js_CastAsObject(getter); } jsval getterValue() const { JS_ASSERT(hasGetterObject()); return js_CastAsObjectJSVal(getter); } bool hasSetterObject() const { return attrs & JSPROP_SETTER; } JSObject *setterObject() const { JS_ASSERT(hasSetterObject()); return js_CastAsObject(setter); } jsval setterValue() const { JS_ASSERT(hasSetterObject()); return js_CastAsObjectJSVal(setter); } bool get(JSContext* cx, JSObject* obj, JSObject *pobj, jsval* vp); bool set(JSContext* cx, JSObject* obj, jsval* vp); void trace(JSTracer *trc); }; /* JSScopeProperty pointer tag bit indicating a collision. */ #define SPROP_COLLISION ((jsuword)1) #define SPROP_REMOVED ((JSScopeProperty *) SPROP_COLLISION) /* Macros to get and set sprop pointer values and collision flags. */ #define SPROP_IS_FREE(sprop) ((sprop) == NULL) #define SPROP_IS_REMOVED(sprop) ((sprop) == SPROP_REMOVED) #define SPROP_IS_LIVE(sprop) ((sprop) > SPROP_REMOVED) #define SPROP_FLAG_COLLISION(spp,sprop) (*(spp) = (JSScopeProperty *) \ ((jsuword)(sprop) | SPROP_COLLISION)) #define SPROP_HAD_COLLISION(sprop) ((jsuword)(sprop) & SPROP_COLLISION) #define SPROP_FETCH(spp) SPROP_CLEAR_COLLISION(*(spp)) #define SPROP_CLEAR_COLLISION(sprop) \ ((JSScopeProperty *) ((jsuword)(sprop) & ~SPROP_COLLISION)) #define SPROP_STORE_PRESERVING_COLLISION(spp, sprop) \ (*(spp) = (JSScopeProperty *) ((jsuword)(sprop) \ | SPROP_HAD_COLLISION(*(spp)))) inline JSScopeProperty * JSScope::lookup(jsid id) { return SPROP_FETCH(search(id, false)); } inline bool JSScope::has(JSScopeProperty *sprop) { return lookup(sprop->id) == sprop; } /* * If SPROP_HAS_SHORTID is set in sprop->flags, we use sprop->shortid rather * than id when calling sprop's getter or setter. */ #define SPROP_USERID(sprop) \ (((sprop)->flags & SPROP_HAS_SHORTID) ? INT_TO_JSVAL((sprop)->shortid) \ : ID_TO_VALUE((sprop)->id)) #define SPROP_INVALID_SLOT 0xffffffff #define SLOT_IN_SCOPE(slot,scope) ((slot) < (scope)->freeslot) #define SPROP_HAS_VALID_SLOT(sprop,scope) SLOT_IN_SCOPE((sprop)->slot, scope) #define SPROP_HAS_STUB_GETTER(sprop) (!(sprop)->getter) #define SPROP_HAS_STUB_SETTER(sprop) (!(sprop)->setter) #define SPROP_HAS_STUB_GETTER_OR_IS_METHOD(sprop) \ (SPROP_HAS_STUB_GETTER(sprop) || (sprop)->isMethod()) #ifndef JS_THREADSAFE # define js_GenerateShape(cx, gcLocked) js_GenerateShape (cx) #endif extern uint32 js_GenerateShape(JSContext *cx, bool gcLocked); #ifdef JS_DUMP_PROPTREE_STATS struct JSScopeStats { jsrefcount searches; jsrefcount hits; jsrefcount misses; jsrefcount hashes; jsrefcount steps; jsrefcount stepHits; jsrefcount stepMisses; jsrefcount adds; jsrefcount redundantAdds; jsrefcount addFailures; jsrefcount changeFailures; jsrefcount compresses; jsrefcount grows; jsrefcount removes; jsrefcount removeFrees; jsrefcount uselessRemoves; jsrefcount shrinks; }; extern JS_FRIEND_DATA(JSScopeStats) js_scope_stats; # define METER(x) JS_ATOMIC_INCREMENT(&js_scope_stats.x) #else # define METER(x) /* nothing */ #endif inline JSScopeProperty ** JSScope::search(jsid id, bool adding) { JSScopeProperty *sprop, **spp; METER(searches); if (!table) { /* Not enough properties to justify hashing: search from lastProp. */ JS_ASSERT(!hadMiddleDelete()); for (spp = &lastProp; (sprop = *spp); spp = &sprop->parent) { if (sprop->id == id) { METER(hits); return spp; } } METER(misses); return spp; } return searchTable(id, adding); } #undef METER inline void JSScope::hold() { JS_ASSERT(nrefs >= 0); JS_ATOMIC_INCREMENT(&nrefs); } inline bool JSScope::drop(JSContext *cx, JSObject *obj) { #ifdef JS_THREADSAFE /* We are called from only js_ShareWaitingTitles and js_FinalizeObject. */ JS_ASSERT(!obj || CX_THREAD_IS_RUNNING_GC(cx)); #endif JS_ASSERT(nrefs > 0); --nrefs; if (nrefs == 0) { destroy(cx, this); return false; } if (object == obj) object = NULL; return true; } inline void JSScope::extend(JSContext *cx, JSScopeProperty *sprop) { js_LeaveTraceIfGlobalObject(cx, object); shape = (!lastProp || shape == lastProp->shape) ? sprop->shape : js_GenerateShape(cx, false); ++entryCount; lastProp = sprop; jsuint index; if (js_IdIsIndex(sprop->id, &index)) setIndexedProperties(); if (sprop->isMethod()) setMethodBarrier(); } /* * Property read barrier for deferred cloning of compiler-created function * objects optimized as typically non-escaping, ad-hoc methods in obj. * * Called only from JSScopeProperty::get when sprop->isMethod(), or JIT- * equivalent code. sprop->isMethod() implies that scope->hasMethodBarrier() * for the scope containing that sprop. */ inline bool JSScope::methodReadBarrier(JSContext *cx, JSScopeProperty *sprop, jsval *vp) { JS_ASSERT(hasMethodBarrier()); JS_ASSERT(has(sprop)); JS_ASSERT(sprop->isMethod()); JS_ASSERT(sprop->methodValue() == *vp); JS_ASSERT(object->getClass() == &js_ObjectClass); JSObject *funobj = JSVAL_TO_OBJECT(*vp); JSFunction *fun = GET_FUNCTION_PRIVATE(cx, funobj); JS_ASSERT(FUN_OBJECT(fun) == funobj && FUN_NULL_CLOSURE(fun)); funobj = js_CloneFunctionObject(cx, fun, OBJ_GET_PARENT(cx, funobj)); if (!funobj) return false; *vp = OBJECT_TO_JSVAL(funobj); return js_SetPropertyHelper(cx, object, sprop->id, 0, vp); } inline bool JSScope::methodWriteBarrier(JSContext *cx, JSScopeProperty *sprop, jsval v) { if (branded()) { jsval prev = LOCKED_OBJ_GET_SLOT(object, sprop->slot); if (prev != v && VALUE_IS_FUNCTION(cx, prev)) return methodShapeChange(cx, sprop, v); } return true; } inline bool JSScope::methodWriteBarrier(JSContext *cx, uint32 slot, jsval v) { if (branded()) { jsval prev = LOCKED_OBJ_GET_SLOT(object, slot); if (prev != v && VALUE_IS_FUNCTION(cx, prev)) return methodShapeChange(cx, slot, v); } return true; } inline void JSScope::trace(JSTracer *trc) { JSContext *cx = trc->context; JSScopeProperty *sprop = lastProp; uint8 regenFlag = cx->runtime->gcRegenShapesScopeFlag; if (IS_GC_MARKING_TRACER(trc) && cx->runtime->gcRegenShapes && hasRegenFlag(regenFlag)) { /* * Either this scope has its own shape, which must be regenerated, or * it must have the same shape as lastProp. */ uint32 newShape; if (sprop) { if (!(sprop->flags & SPROP_FLAG_SHAPE_REGEN)) { sprop->shape = js_RegenerateShapeForGC(cx); sprop->flags |= SPROP_FLAG_SHAPE_REGEN; } newShape = sprop->shape; } if (!sprop || hasOwnShape()) { newShape = js_RegenerateShapeForGC(cx); JS_ASSERT_IF(sprop, newShape != sprop->shape); } shape = newShape; flags ^= JSScope::SHAPE_REGEN; /* Also regenerate the shapes of empty scopes, in case they are not shared. */ for (JSScope *empty = emptyScope; empty && empty->hasRegenFlag(regenFlag); empty = empty->emptyScope) { empty->shape = js_RegenerateShapeForGC(cx); empty->flags ^= JSScope::SHAPE_REGEN; } } if (sprop) { JS_ASSERT(has(sprop)); /* Trace scope's property tree ancestor line. */ do { if (hadMiddleDelete() && !has(sprop)) continue; sprop->trace(trc); } while ((sprop = sprop->parent) != NULL); } } inline bool JSScopeProperty::get(JSContext* cx, JSObject* obj, JSObject *pobj, jsval* vp) { JS_ASSERT(!SPROP_HAS_STUB_GETTER(this)); JS_ASSERT(!JSVAL_IS_NULL(this->id)); if (attrs & JSPROP_GETTER) { JS_ASSERT(!isMethod()); jsval fval = getterValue(); return js_InternalGetOrSet(cx, obj, id, fval, JSACC_READ, 0, 0, vp); } if (isMethod()) { *vp = methodValue(); JSScope *scope = OBJ_SCOPE(pobj); JS_ASSERT(scope->object == pobj); return scope->methodReadBarrier(cx, this, vp); } /* * JSObjectOps is private, so we know there are only two implementations * of the thisObject hook: with objects and XPConnect wrapped native * objects. XPConnect objects don't expect the hook to be called here, * but with objects do. */ if (STOBJ_GET_CLASS(obj) == &js_WithClass) obj = obj->map->ops->thisObject(cx, obj); return getter(cx, obj, SPROP_USERID(this), vp); } inline bool JSScopeProperty::set(JSContext* cx, JSObject* obj, jsval* vp) { JS_ASSERT_IF(SPROP_HAS_STUB_SETTER(this), attrs & JSPROP_GETTER); if (attrs & JSPROP_SETTER) { jsval fval = setterValue(); return js_InternalGetOrSet(cx, obj, id, fval, JSACC_WRITE, 1, vp, vp); } if (attrs & JSPROP_GETTER) { js_ReportGetterOnlyAssignment(cx); return false; } /* See the comment in JSScopeProperty::get as to why we can check for With. */ if (STOBJ_GET_CLASS(obj) == &js_WithClass) obj = obj->map->ops->thisObject(cx, obj); return setter(cx, obj, SPROP_USERID(this), vp); } /* Macro for common expression to test for shared permanent attributes. */ #define SPROP_IS_SHARED_PERMANENT(sprop) \ ((~(sprop)->attrs & (JSPROP_SHARED | JSPROP_PERMANENT)) == 0) extern JSScope * js_GetMutableScope(JSContext *cx, JSObject *obj); extern void js_TraceId(JSTracer *trc, jsid id); extern void js_SweepScopeProperties(JSContext *cx); extern bool js_InitPropertyTree(JSRuntime *rt); extern void js_FinishPropertyTree(JSRuntime *rt); JS_END_EXTERN_C #ifdef _MSC_VER #pragma warning(pop) #endif #endif /* jsscope_h___ */