1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/vm/SavedStacks.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,144 @@
1.4 +
1.5 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.6 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.7 + * This Source Code Form is subject to the terms of the Mozilla Public
1.8 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.9 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.10 +
1.11 +#ifndef vm_SavedStacks_h
1.12 +#define vm_SavedStacks_h
1.13 +
1.14 +#include "jscntxt.h"
1.15 +#include "js/HashTable.h"
1.16 +#include "vm/Stack.h"
1.17 +
1.18 +namespace js {
1.19 +
1.20 +class SavedFrame : public JSObject {
1.21 + friend class SavedStacks;
1.22 +
1.23 + public:
1.24 + static const Class class_;
1.25 + static void finalize(FreeOp *fop, JSObject *obj);
1.26 +
1.27 + // Prototype methods and properties to be exposed to JS.
1.28 + static const JSPropertySpec properties[];
1.29 + static const JSFunctionSpec methods[];
1.30 + static bool construct(JSContext *cx, unsigned argc, Value *vp);
1.31 + static bool sourceProperty(JSContext *cx, unsigned argc, Value *vp);
1.32 + static bool lineProperty(JSContext *cx, unsigned argc, Value *vp);
1.33 + static bool columnProperty(JSContext *cx, unsigned argc, Value *vp);
1.34 + static bool functionDisplayNameProperty(JSContext *cx, unsigned argc, Value *vp);
1.35 + static bool parentProperty(JSContext *cx, unsigned argc, Value *vp);
1.36 + static bool toStringMethod(JSContext *cx, unsigned argc, Value *vp);
1.37 +
1.38 + // Convenient getters for SavedFrame's reserved slots for use from C++.
1.39 + JSAtom *getSource();
1.40 + size_t getLine();
1.41 + size_t getColumn();
1.42 + JSAtom *getFunctionDisplayName();
1.43 + SavedFrame *getParent();
1.44 + JSPrincipals *getPrincipals();
1.45 +
1.46 + bool isSelfHosted();
1.47 +
1.48 + struct Lookup;
1.49 + struct HashPolicy;
1.50 +
1.51 + typedef HashSet<SavedFrame *,
1.52 + HashPolicy,
1.53 + SystemAllocPolicy> Set;
1.54 +
1.55 + private:
1.56 + void initFromLookup(Lookup &lookup);
1.57 +
1.58 + enum {
1.59 + // The reserved slots in the SavedFrame class.
1.60 + JSSLOT_SOURCE,
1.61 + JSSLOT_LINE,
1.62 + JSSLOT_COLUMN,
1.63 + JSSLOT_FUNCTIONDISPLAYNAME,
1.64 + JSSLOT_PARENT,
1.65 + JSSLOT_PRINCIPALS,
1.66 + JSSLOT_PRIVATE_PARENT,
1.67 +
1.68 + // The total number of reserved slots in the SavedFrame class.
1.69 + JSSLOT_COUNT
1.70 + };
1.71 +
1.72 + // Because we hash the parent pointer, we need to rekey a saved frame
1.73 + // whenever its parent was relocated by the GC. However, the GC doesn't
1.74 + // notify us when this occurs. As a work around, we keep a duplicate copy of
1.75 + // the parent pointer as a private value in a reserved slot. Whenever the
1.76 + // private value parent pointer doesn't match the regular parent pointer, we
1.77 + // know that GC moved the parent and we need to update our private value and
1.78 + // rekey the saved frame in its hash set. These two methods are helpers for
1.79 + // this process.
1.80 + bool parentMoved();
1.81 + void updatePrivateParent();
1.82 +
1.83 + static SavedFrame *checkThis(JSContext *cx, CallArgs &args, const char *fnName);
1.84 +};
1.85 +
1.86 +struct SavedFrame::Lookup {
1.87 + Lookup(JSAtom *source, size_t line, size_t column, JSAtom *functionDisplayName,
1.88 + Handle<SavedFrame*> parent, JSPrincipals *principals)
1.89 + : source(source),
1.90 + line(line),
1.91 + column(column),
1.92 + functionDisplayName(functionDisplayName),
1.93 + parent(parent),
1.94 + principals(principals)
1.95 + {
1.96 + JS_ASSERT(source);
1.97 + }
1.98 +
1.99 + JSAtom *source;
1.100 + size_t line;
1.101 + size_t column;
1.102 + JSAtom *functionDisplayName;
1.103 + Handle<SavedFrame*> parent;
1.104 + JSPrincipals *principals;
1.105 +};
1.106 +
1.107 +struct SavedFrame::HashPolicy
1.108 +{
1.109 + typedef SavedFrame::Lookup Lookup;
1.110 + typedef PointerHasher<SavedFrame *, 3> SavedFramePtrHasher;
1.111 + typedef PointerHasher<JSPrincipals *, 3> JSPrincipalsPtrHasher;
1.112 +
1.113 + static HashNumber hash(const Lookup &lookup);
1.114 + static bool match(SavedFrame *existing, const Lookup &lookup);
1.115 +
1.116 + typedef SavedFrame* Key;
1.117 + static void rekey(Key &key, const Key &newKey);
1.118 +};
1.119 +
1.120 +class SavedStacks {
1.121 + public:
1.122 + SavedStacks() : frames(), savedFrameProto(nullptr) { }
1.123 +
1.124 + bool init();
1.125 + bool initialized() const { return frames.initialized(); }
1.126 + bool saveCurrentStack(JSContext *cx, MutableHandle<SavedFrame*> frame);
1.127 + void sweep(JSRuntime *rt);
1.128 + uint32_t count();
1.129 + void clear();
1.130 +
1.131 + size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf);
1.132 +
1.133 + private:
1.134 + SavedFrame::Set frames;
1.135 + JSObject *savedFrameProto;
1.136 +
1.137 + bool insertFrames(JSContext *cx, ScriptFrameIter &iter, MutableHandle<SavedFrame*> frame);
1.138 + SavedFrame *getOrCreateSavedFrame(JSContext *cx, SavedFrame::Lookup &lookup);
1.139 + // |SavedFrame.prototype| is created lazily and held weakly. It should only
1.140 + // be accessed through this method.
1.141 + JSObject *getOrCreateSavedFramePrototype(JSContext *cx);
1.142 + SavedFrame *createFrameFromLookup(JSContext *cx, SavedFrame::Lookup &lookup);
1.143 +};
1.144 +
1.145 +} /* namespace js */
1.146 +
1.147 +#endif /* vm_SavedStacks_h */
