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1 // Copyright 2020 the V8 project authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #include "src/snapshot/snapshot-data.h"
6 
7 #include "src/common/assert-scope.h"
8 #include "src/snapshot/serializer.h"
9 
10 namespace v8 {
11 namespace internal {
12 
AllocateData(uint32_t size)13 void SerializedData::AllocateData(uint32_t size) {
14   DCHECK(!owns_data_);
15   data_ = NewArray<byte>(size);
16   size_ = size;
17   owns_data_ = true;
18 }
19 
20 // static
21 constexpr uint32_t SerializedData::kMagicNumber;
22 
SnapshotData(const Serializer * serializer)23 SnapshotData::SnapshotData(const Serializer* serializer) {
24   DisallowGarbageCollection no_gc;
25   const std::vector<byte>* payload = serializer->Payload();
26 
27   // Calculate sizes.
28   uint32_t size = kHeaderSize + static_cast<uint32_t>(payload->size());
29 
30   // Allocate backing store and create result data.
31   AllocateData(size);
32 
33   // Zero out pre-payload data. Part of that is only used for padding.
34   memset(data_, 0, kHeaderSize);
35 
36   // Set header values.
37   SetMagicNumber();
38   SetHeaderValue(kPayloadLengthOffset, static_cast<int>(payload->size()));
39 
40   // Copy serialized data.
41   CopyBytes(data_ + kHeaderSize, payload->data(),
42             static_cast<size_t>(payload->size()));
43 }
44 
Payload() const45 base::Vector<const byte> SnapshotData::Payload() const {
46   const byte* payload = data_ + kHeaderSize;
47   uint32_t length = GetHeaderValue(kPayloadLengthOffset);
48   DCHECK_EQ(data_ + size_, payload + length);
49   return base::Vector<const byte>(payload, length);
50 }
51 
52 }  // namespace internal
53 }  // namespace v8
54