forked from mirrors/gecko-dev
b6da7dc336
For nsXPCWrappedJS, we need to add an edge to the cycle collector graph from the JS object to its WJS, even though the JS object does not actually contain a pointer to the WJS object. We can (mis)use the weak mapping interface for this purpose. The only difference is that we need it during traversal instead of while adding roots. The API is fairly specialized to the specific use case we need. Differential Revision: https://phabricator.services.mozilla.com/D157529
70 lines
2.4 KiB
C++
70 lines
2.4 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsCycleCollectionTraversalCallback_h__
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#define nsCycleCollectionTraversalCallback_h__
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#include <cstdint>
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#include "nscore.h"
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class nsCycleCollectionParticipant;
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class nsISupports;
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class JSObject;
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namespace JS {
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class GCCellPtr;
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}
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class NS_NO_VTABLE nsCycleCollectionTraversalCallback {
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public:
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// You must call DescribeRefCountedNode() with an accurate
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// refcount, otherwise cycle collection will fail, and probably crash.
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// If the callback cares about objname, it should put
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// WANT_DEBUG_INFO in mFlags.
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NS_IMETHOD_(void)
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DescribeRefCountedNode(nsrefcnt aRefcount, const char* aObjName) = 0;
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// Note, aCompartmentAddress is 0 if it is unknown.
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NS_IMETHOD_(void)
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DescribeGCedNode(bool aIsMarked, const char* aObjName,
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uint64_t aCompartmentAddress = 0) = 0;
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NS_IMETHOD_(void) NoteXPCOMChild(nsISupports* aChild) = 0;
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NS_IMETHOD_(void) NoteJSChild(JS::GCCellPtr aThing) = 0;
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NS_IMETHOD_(void)
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NoteNativeChild(void* aChild, nsCycleCollectionParticipant* aHelper) = 0;
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NS_IMETHOD_(void)
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NoteWeakMapping(JSObject* aKey, nsISupports* aVal,
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nsCycleCollectionParticipant* aValParticipant) = 0;
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// Give a name to the edge associated with the next call to
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// NoteXPCOMChild, NoteJSObject, NoteJSScript, or NoteNativeChild.
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// Callbacks who care about this should set WANT_DEBUG_INFO in the
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// flags.
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NS_IMETHOD_(void) NoteNextEdgeName(const char* aName) = 0;
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enum {
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// Values for flags:
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// Caller should call NoteNextEdgeName and pass useful objName
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// to DescribeRefCountedNode and DescribeGCedNode.
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WANT_DEBUG_INFO = (1 << 0),
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// Caller should not skip objects that we know will be
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// uncollectable.
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WANT_ALL_TRACES = (1 << 1)
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};
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uint32_t Flags() const { return mFlags; }
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bool WantDebugInfo() const { return (mFlags & WANT_DEBUG_INFO) != 0; }
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bool WantAllTraces() const { return (mFlags & WANT_ALL_TRACES) != 0; }
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protected:
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nsCycleCollectionTraversalCallback() : mFlags(0) {}
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uint32_t mFlags;
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};
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#endif // nsCycleCollectionTraversalCallback_h__
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