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v8-context.h
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1// Copyright 2021 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 INCLUDE_V8_CONTEXT_H_
6#define INCLUDE_V8_CONTEXT_H_
7
8#include <stdint.h>
9
10#include <vector>
11
12#include "v8-data.h" // NOLINT(build/include_directory)
13#include "v8-local-handle.h" // NOLINT(build/include_directory)
14#include "v8-maybe.h" // NOLINT(build/include_directory)
15#include "v8-snapshot.h" // NOLINT(build/include_directory)
16#include "v8config.h" // NOLINT(build/include_directory)
17
18namespace v8 {
19
20class Function;
21class MicrotaskQueue;
22class Object;
23class ObjectTemplate;
24class Value;
25class String;
26
31 public:
32 ExtensionConfiguration() : name_count_(0), names_(nullptr) {}
33 ExtensionConfiguration(int name_count, const char* names[])
34 : name_count_(name_count), names_(names) {}
35
36 const char** begin() const { return &names_[0]; }
37 const char** end() const { return &names_[name_count_]; }
38
39 private:
40 const int name_count_;
41 const char** names_;
42};
43
48class V8_EXPORT Context : public Data {
49 public:
63
69
116 Isolate* isolate, ExtensionConfiguration* extensions = nullptr,
118 MaybeLocal<Value> global_object = MaybeLocal<Value>(),
119 DeserializeInternalFieldsCallback internal_fields_deserializer =
121 MicrotaskQueue* microtask_queue = nullptr,
122 DeserializeContextDataCallback context_data_deserializer =
124 DeserializeAPIWrapperCallback api_wrapper_deserializer =
126
164 Isolate* isolate, size_t context_snapshot_index,
165 DeserializeInternalFieldsCallback internal_fields_deserializer =
167 ExtensionConfiguration* extensions = nullptr,
168 MaybeLocal<Value> global_object = MaybeLocal<Value>(),
169 MicrotaskQueue* microtask_queue = nullptr,
170 DeserializeContextDataCallback context_data_deserializer =
172 DeserializeAPIWrapperCallback api_wrapper_deserializer =
174
193 Isolate* isolate, Local<ObjectTemplate> global_template,
194 MaybeLocal<Value> global_object = MaybeLocal<Value>());
195
201
204
207
214 void Enter();
215
220 void Exit();
221
227 public:
238 Local<Object> obj, LocalVector<Object>& children_out) = 0;
239 };
240
257
260
263
268 enum EmbedderDataFields { kDebugIdIndex = 0 };
269
274
279 V8_INLINE Local<Value> GetEmbedderData(int index);
280
288
294 void SetEmbedderData(int index, Local<Value> value);
295
302 V8_INLINE void* GetAlignedPointerFromEmbedderData(Isolate* isolate, int index,
304 V8_INLINE void* GetAlignedPointerFromEmbedderData(int index,
306
308 "Use GetAlignedPointerFromEmbedderData with EmbedderDataTypeTag "
309 "parameter instead.")
310 V8_INLINE void* GetAlignedPointerFromEmbedderData(Isolate* isolate,
311 int index) {
312 return GetAlignedPointerFromEmbedderData(isolate, index,
314 }
315
317 "Use GetAlignedPointerFromEmbedderData with EmbedderDataTypeTag "
318 "parameter instead.")
319 V8_INLINE void* GetAlignedPointerFromEmbedderData(int index) {
320 return GetAlignedPointerFromEmbedderData(index,
322 }
323
324 void SetAlignedPointerInEmbedderData(int index, void* value,
326
333 "Use SetAlignedPointerInEmbedderData with EmbedderDataTypeTag parameter "
334 "instead.")
335 void SetAlignedPointerInEmbedderData(int index, void* value) {
336 SetAlignedPointerInEmbedderData(index, value, kEmbedderDataTypeTagDefault);
337 }
338
353
359
366
372
378 template <class T>
379 V8_INLINE MaybeLocal<T> GetDataFromSnapshotOnce(size_t index);
380
386 using AbortScriptExecutionCallback = void (*)(Isolate* isolate,
387 Local<Context> context);
389
398 Local<Function> after_hook,
399 Local<Function> resolve_hook);
400
407 public:
408 explicit V8_INLINE Scope(Local<Context> context) : context_(context) {
409 context_->Enter();
410 }
411 V8_INLINE ~Scope() { context_->Exit(); }
412
413 private:
414 Local<Context> context_;
415 };
416
423 public:
428 explicit BackupIncumbentScope(Local<Context> backup_incumbent_context);
430
431 private:
432 friend class internal::Isolate;
433
434 uintptr_t JSStackComparableAddressPrivate() const {
435 return js_stack_comparable_address_;
436 }
437
438 Local<Context> backup_incumbent_context_;
439 uintptr_t js_stack_comparable_address_ = 0;
440 const BackupIncumbentScope* prev_ = nullptr;
441 };
442
443 V8_INLINE static Context* Cast(Data* data);
444
445 private:
446 friend class Value;
447 friend class Script;
448 friend class Object;
449 friend class Function;
450
451 static void CheckCast(Data* obj);
452
454 size_t index);
455 Local<Value> SlowGetEmbedderData(int index);
456 void* SlowGetAlignedPointerFromEmbedderData(int index,
458};
459
460// --- Implementation ---
461
463#ifndef V8_ENABLE_CHECKS
464 using A = internal::Address;
465 using I = internal::Internals;
467 A embedder_data =
468 I::ReadTaggedPointerField(ctx, I::kNativeContextEmbedderDataOffset);
469 int value_offset =
470 I::kEmbedderDataArrayHeaderSize + (I::kEmbedderDataSlotSize * index);
471 A value = I::ReadRawField<A>(embedder_data, value_offset);
472#ifdef V8_COMPRESS_POINTERS
473 // We read the full pointer value and then decompress it in order to avoid
474 // dealing with potential endiannes issues.
475 value = I::DecompressTaggedField(embedder_data, static_cast<uint32_t>(value));
476#endif
477
478 auto* isolate = I::GetCurrentIsolate();
479 return Local<Value>::New(isolate, value);
480#else
481 return SlowGetEmbedderData(index);
482#endif
483}
484
487#if !defined(V8_ENABLE_CHECKS)
488 using A = internal::Address;
489 using I = internal::Internals;
491 A embedder_data =
492 I::ReadTaggedPointerField(ctx, I::kNativeContextEmbedderDataOffset);
493 int value_offset = I::kEmbedderDataArrayHeaderSize +
494 (I::kEmbedderDataSlotSize * index) +
495 I::kEmbedderDataSlotExternalPointerOffset;
496 return reinterpret_cast<void*>(I::ReadExternalPointerField(
497 isolate, embedder_data, value_offset, ToExternalPointerTag(tag)));
498#else
499 return SlowGetAlignedPointerFromEmbedderData(index, tag);
500#endif
501}
502
505#if !defined(V8_ENABLE_CHECKS)
506 using A = internal::Address;
507 using I = internal::Internals;
509 A embedder_data =
510 I::ReadTaggedPointerField(ctx, I::kNativeContextEmbedderDataOffset);
511 int value_offset = I::kEmbedderDataArrayHeaderSize +
512 (I::kEmbedderDataSlotSize * index) +
513 I::kEmbedderDataSlotExternalPointerOffset;
514 Isolate* isolate = I::GetCurrentIsolateForSandbox();
515 return reinterpret_cast<void*>(I::ReadExternalPointerField(
516 isolate, embedder_data, value_offset, ToExternalPointerTag(tag)));
517#else
518 return SlowGetAlignedPointerFromEmbedderData(index, tag);
519#endif
520}
521
522template <class T>
524 if (auto repr = GetDataFromSnapshotOnce(index);
526 internal::PerformCastCheck(internal::ValueHelper::ReprAsValue<T>(repr));
527 return Local<T>::FromRepr(repr);
528 }
529 return {};
530}
531
533#ifdef V8_ENABLE_CHECKS
534 CheckCast(data);
535#endif
536 return static_cast<Context*>(data);
537}
538
539} // namespace v8
540
541#endif // INCLUDE_V8_CONTEXT_H_
Definition: v8-context.h:422
BackupIncumbentScope(Local< Context > backup_incumbent_context)
Definition: v8-context.h:226
virtual bool FreezeEmbedderObjectAndGetChildren(Local< Object > obj, LocalVector< Object > &children_out)=0
Definition: v8-context.h:406
Scope(Local< Context > context)
Definition: v8-context.h:408
~Scope()
Definition: v8-context.h:411
Definition: v8-context.h:48
static MaybeLocal< Object > NewRemoteContext(Isolate *isolate, Local< ObjectTemplate > global_template, MaybeLocal< Value > global_object=MaybeLocal< Value >())
Local< Object > GetExtrasBindingObject()
void SetErrorMessageForWasmCodeGeneration(Local< String > message)
void SetEmbedderData(int index, Local< Value > value)
void SetPromiseHooks(Local< Function > init_hook, Local< Function > before_hook, Local< Function > after_hook, Local< Function > resolve_hook)
void SetSecurityToken(Local< Value > token)
static Local< Context > New(Isolate *isolate, ExtensionConfiguration *extensions=nullptr, MaybeLocal< ObjectTemplate > global_template=MaybeLocal< ObjectTemplate >(), MaybeLocal< Value > global_object=MaybeLocal< Value >(), DeserializeInternalFieldsCallback internal_fields_deserializer=DeserializeInternalFieldsCallback(), MicrotaskQueue *microtask_queue=nullptr, DeserializeContextDataCallback context_data_deserializer=DeserializeContextDataCallback(), DeserializeAPIWrapperCallback api_wrapper_deserializer=DeserializeAPIWrapperCallback())
bool IsCodeGenerationFromStringsAllowed() const
static Context * Cast(Data *data)
Definition: v8-context.h:532
MicrotaskQueue * GetMicrotaskQueue()
void Enter()
void SetAbortScriptExecution(AbortScriptExecutionCallback callback)
Maybe< void > DeepFreeze(DeepFreezeDelegate *delegate=nullptr)
bool HasTemplateLiteralObject(Local< Value > object)
void AllowCodeGenerationFromStrings(bool allow)
Local< Value > GetSecurityToken()
MaybeLocal< T > GetDataFromSnapshotOnce(size_t index)
Definition: v8-context.h:523
void DetachGlobal()
void SetErrorMessageForCodeGenerationFromStrings(Local< String > message)
EmbedderDataFields
Definition: v8-context.h:268
uint32_t GetNumberOfEmbedderDataFields()
Local< Value > GetEmbedderData(int index)
Definition: v8-context.h:462
void SetMicrotaskQueue(MicrotaskQueue *queue)
void UseDefaultSecurityToken()
void * GetAlignedPointerFromEmbedderData(Isolate *isolate, int index, EmbedderDataTypeTag tag)
Definition: v8-context.h:485
void(*)(Isolate *isolate, Local< Context > context) AbortScriptExecutionCallback
Definition: v8-context.h:387
static MaybeLocal< Context > FromSnapshot(Isolate *isolate, size_t context_snapshot_index, DeserializeInternalFieldsCallback internal_fields_deserializer=DeserializeInternalFieldsCallback(), ExtensionConfiguration *extensions=nullptr, MaybeLocal< Value > global_object=MaybeLocal< Value >(), MicrotaskQueue *microtask_queue=nullptr, DeserializeContextDataCallback context_data_deserializer=DeserializeContextDataCallback(), DeserializeAPIWrapperCallback api_wrapper_deserializer=DeserializeAPIWrapperCallback())
Local< Object > Global()
void SetAlignedPointerInEmbedderData(int index, void *value, EmbedderDataTypeTag tag)
Definition: v8-data.h:18
Definition: v8-context.h:30
ExtensionConfiguration(int name_count, const char *names[])
Definition: v8-context.h:33
ExtensionConfiguration()
Definition: v8-context.h:32
const char ** begin() const
Definition: v8-context.h:36
const char ** end() const
Definition: v8-context.h:37
Definition: v8-function.h:27
Definition: v8-isolate.h:290
Definition: v8-local-handle.h:594
Definition: v8-local-handle.h:366
static Local< T > New(Isolate *isolate, Local< T > that)
Definition: v8-local-handle.h:448
Definition: v8-local-handle.h:734
Definition: v8-maybe.h:39
Definition: v8-microtask-queue.h:40
Definition: v8-object.h:248
Definition: v8-script.h:370
Definition: v8-value.h:32
Definition: v8-internal.h:878
static Address ValueAsAddress(const T *value)
Definition: v8-internal.h:1723
internal::Address * InternalRepresentationType
Definition: v8-internal.h:1677
static constexpr InternalRepresentationType kEmpty
Definition: v8-internal.h:1678
uintptr_t Address
Definition: v8-internal.h:38
void PerformCastCheck(T *data)
Definition: v8-internal.h:1443
Definition: libplatform.h:15
internal::ExternalPointerTag ToExternalPointerTag(v8::EmbedderDataTypeTag api_tag)
constexpr EmbedderDataTypeTag kEmbedderDataTypeTagDefault
Definition: v8-object.h:36
uint16_t EmbedderDataTypeTag
Definition: v8-object.h:34
Definition: v8-snapshot.h:116
Definition: v8-snapshot.h:106
Definition: v8-snapshot.h:91
#define V8_EXPORT
Definition: v8config.h:855
#define V8_INLINE
Definition: v8config.h:508
#define V8_DEPRECATE_SOON(message)
Definition: v8config.h:622
#define V8_NODISCARD
Definition: v8config.h:701