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      1 // Copyright 2011 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 #ifndef V8_SNAPSHOT_NATIVES_H_
      6 #define V8_SNAPSHOT_NATIVES_H_
      7 
      8 #include "include/v8.h"
      9 #include "src/objects.h"
     10 #include "src/vector.h"
     11 
     12 namespace v8 { class StartupData; }  // Forward declaration.
     13 
     14 namespace v8 {
     15 namespace internal {
     16 
     17 enum NativeType {
     18   CORE,
     19   EXTRAS,
     20   EXPERIMENTAL_EXTRAS,
     21   D8,
     22   TEST
     23 };
     24 
     25 // Extra handling for V8_EXPORT_PRIVATE in combination with USING_V8_SHARED
     26 // since definition of methods of classes marked as dllimport is not allowed.
     27 template <NativeType type>
     28 #ifdef USING_V8_SHARED
     29 class NativesCollection {
     30 #else
     31 class V8_EXPORT_PRIVATE NativesCollection {
     32 #endif  // USING_V8_SHARED
     33 
     34  public:
     35   // The following methods are implemented in js2c-generated code:
     36 
     37   // Number of built-in scripts.
     38   static int GetBuiltinsCount();
     39   // Number of debugger implementation scripts.
     40   static int GetDebuggerCount();
     41 
     42   // These are used to access built-in scripts.  The debugger implementation
     43   // scripts have an index in the interval [0, GetDebuggerCount()).  The
     44   // non-debugger scripts have an index in the interval [GetDebuggerCount(),
     45   // GetNativesCount()).
     46   static int GetIndex(const char* name);
     47   static Vector<const char> GetScriptSource(int index);
     48   static Vector<const char> GetScriptName(int index);
     49   static Vector<const char> GetScriptsSource();
     50 };
     51 
     52 typedef NativesCollection<CORE> Natives;
     53 typedef NativesCollection<EXTRAS> ExtraNatives;
     54 typedef NativesCollection<EXPERIMENTAL_EXTRAS> ExperimentalExtraNatives;
     55 
     56 
     57 #ifdef V8_USE_EXTERNAL_STARTUP_DATA
     58 // Used for reading the natives at runtime. Implementation in natives-empty.cc
     59 void SetNativesFromFile(StartupData* natives_blob);
     60 void ReadNatives();
     61 void DisposeNatives();
     62 #endif
     63 
     64 class NativesExternalStringResource final
     65     : public v8::String::ExternalOneByteStringResource {
     66  public:
     67   NativesExternalStringResource(NativeType type, int index);
     68 
     69   const char* data() const override { return data_; }
     70   size_t length() const override { return length_; }
     71 
     72   v8::String::ExternalOneByteStringResource* EncodeForSerialization() const {
     73     DCHECK(type_ == CORE || type_ == EXTRAS);
     74     intptr_t val = (index_ << 1) | ((type_ == CORE) ? 0 : 1);
     75     val = val << kPointerSizeLog2;  // Pointer align.
     76     return reinterpret_cast<v8::String::ExternalOneByteStringResource*>(val);
     77   }
     78 
     79   // Decode from serialization.
     80   static NativesExternalStringResource* DecodeForDeserialization(
     81       const v8::String::ExternalOneByteStringResource* encoded) {
     82     intptr_t val = reinterpret_cast<intptr_t>(encoded) >> kPointerSizeLog2;
     83     NativeType type = (val & 1) ? EXTRAS : CORE;
     84     int index = static_cast<int>(val >> 1);
     85     return new NativesExternalStringResource(type, index);
     86   }
     87 
     88  private:
     89   const char* data_;
     90   size_t length_;
     91   NativeType type_;
     92   int index_;
     93 };
     94 
     95 }  // namespace internal
     96 }  // namespace v8
     97 
     98 #endif  // V8_SNAPSHOT_NATIVES_H_
     99