abe7f841ca
Backed out changeset 3e8d2c47138c (bug 1454816) Backed out changeset 80ff20241831 (bug 1454816) Backed out changeset 28c2d6d2a683 (bug 1454816) Backed out changeset 236943ab4142 (bug 1454816)
141 lines
3.9 KiB
C++
141 lines
3.9 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 "SharedStringMap.h"
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#include "MemMapSnapshot.h"
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#include "ScriptPreloader-inl.h"
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#include "mozilla/BinarySearch.h"
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#include "mozilla/Try.h"
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#include "mozilla/ipc/FileDescriptor.h"
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using namespace mozilla::loader;
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namespace mozilla {
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using namespace ipc;
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namespace dom::ipc {
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static constexpr uint32_t kSharedStringMapMagic = 0x9e3779b9;
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static inline size_t GetAlignmentOffset(size_t aOffset, size_t aAlign) {
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auto mod = aOffset % aAlign;
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return mod ? aAlign - mod : 0;
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}
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SharedStringMap::SharedStringMap(const FileDescriptor& aMapFile,
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size_t aMapSize) {
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auto result = mMap.initWithHandle(aMapFile, aMapSize);
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MOZ_RELEASE_ASSERT(result.isOk());
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MOZ_RELEASE_ASSERT(GetHeader().mMagic == kSharedStringMapMagic);
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// We return literal nsStrings and nsCStrings pointing to the mapped data,
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// which means that we may still have references to the mapped data even
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// after this instance is destroyed. That means that we need to keep the
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// mapping alive until process shutdown, in order to be safe.
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mMap.setPersistent();
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}
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SharedStringMap::SharedStringMap(SharedStringMapBuilder&& aBuilder) {
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auto result = aBuilder.Finalize(mMap);
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MOZ_RELEASE_ASSERT(result.isOk());
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MOZ_RELEASE_ASSERT(GetHeader().mMagic == kSharedStringMapMagic);
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mMap.setPersistent();
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}
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mozilla::ipc::FileDescriptor SharedStringMap::CloneFileDescriptor() const {
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return mMap.cloneHandle();
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}
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bool SharedStringMap::Has(const nsCString& aKey) {
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size_t index;
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return Find(aKey, &index);
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}
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bool SharedStringMap::Get(const nsCString& aKey, nsAString& aValue) {
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const auto& entries = Entries();
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size_t index;
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if (!Find(aKey, &index)) {
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return false;
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}
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aValue.Assign(ValueTable().Get(entries[index].mValue));
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return true;
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}
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bool SharedStringMap::Find(const nsCString& aKey, size_t* aIndex) {
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const auto& keys = KeyTable();
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return BinarySearchIf(
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Entries(), 0, EntryCount(),
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[&](const Entry& aEntry) { return Compare(aKey, keys.Get(aEntry.mKey)); },
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aIndex);
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}
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void SharedStringMapBuilder::Add(const nsCString& aKey,
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const nsString& aValue) {
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mEntries.InsertOrUpdate(aKey,
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Entry{mKeyTable.Add(aKey), mValueTable.Add(aValue)});
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}
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Result<Ok, nsresult> SharedStringMapBuilder::Finalize(
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loader::AutoMemMap& aMap) {
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using Header = SharedStringMap::Header;
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MOZ_ASSERT(mEntries.Count() == mKeyTable.Count());
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auto keys = ToTArray<nsTArray<nsCString>>(mEntries.Keys());
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keys.Sort();
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Header header = {kSharedStringMapMagic, uint32_t(keys.Length())};
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size_t offset = sizeof(header);
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offset += GetAlignmentOffset(offset, alignof(Header));
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offset += keys.Length() * sizeof(SharedStringMap::Entry);
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header.mKeyStringsOffset = offset;
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header.mKeyStringsSize = mKeyTable.Size();
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offset += header.mKeyStringsSize;
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offset +=
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GetAlignmentOffset(offset, alignof(decltype(mValueTable)::ElemType));
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header.mValueStringsOffset = offset;
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header.mValueStringsSize = mValueTable.Size();
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offset += header.mValueStringsSize;
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MemMapSnapshot mem;
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MOZ_TRY(mem.Init(offset));
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auto headerPtr = mem.Get<Header>();
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headerPtr[0] = header;
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auto* entry = reinterpret_cast<Entry*>(&headerPtr[1]);
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for (auto& key : keys) {
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*entry++ = mEntries.Get(key);
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}
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auto ptr = mem.Get<uint8_t>();
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mKeyTable.Write({&ptr[header.mKeyStringsOffset], header.mKeyStringsSize});
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mValueTable.Write(
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{&ptr[header.mValueStringsOffset], header.mValueStringsSize});
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mKeyTable.Clear();
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mValueTable.Clear();
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mEntries.Clear();
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return mem.Finalize(aMap);
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}
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} // namespace dom::ipc
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} // namespace mozilla
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