зеркало из https://github.com/mozilla/gecko-dev.git
55 строки
1.8 KiB
C
55 строки
1.8 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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#include "VTableBuilder.h"
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#include <stdlib.h>
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static HRESULT STDMETHODCALLTYPE QueryInterfaceThunk(IUnknown* aThis,
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REFIID aIid,
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void** aOutInterface) {
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void** table = (void**)aThis;
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IUnknown* real = (IUnknown*)table[1];
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return real->lpVtbl->QueryInterface(real, aIid, aOutInterface);
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}
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static ULONG STDMETHODCALLTYPE AddRefThunk(IUnknown* aThis) {
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void** table = (void**)aThis;
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IUnknown* real = (IUnknown*)table[1];
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return real->lpVtbl->AddRef(real);
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}
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static ULONG STDMETHODCALLTYPE ReleaseThunk(IUnknown* aThis) {
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void** table = (void**)aThis;
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IUnknown* real = (IUnknown*)table[1];
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return real->lpVtbl->Release(real);
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}
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IUnknown* BuildNullVTable(IUnknown* aUnk, uint32_t aVtblSize) {
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void** table;
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if (aVtblSize < 3) {
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return NULL;
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}
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// We need to allocate slots for two additional pointers: The |lpVtbl|
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// pointer, as well as |aUnk| which is needed to get |this| right when
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// something calls through one of the IUnknown thunks.
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table = calloc(aVtblSize + 2, sizeof(void*));
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table[0] = &table[2]; // |lpVtbl|, points to the first entry of the vtable
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table[1] = aUnk; // |this|
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// Now the actual vtable entries for IUnknown
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table[2] = &QueryInterfaceThunk;
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table[3] = &AddRefThunk;
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table[4] = &ReleaseThunk;
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// Remaining entries are NULL thanks to calloc zero-initializing everything.
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return (IUnknown*)table;
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}
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void DeleteNullVTable(IUnknown* aUnk) { free(aUnk); }
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