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// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
#ifndef SRC_UTIL_H_
#define SRC_UTIL_H_
#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#include "v8.h"
#include <assert.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <type_traits> // std::remove_reference
namespace node {
// These should be used in our code as opposed to the native
// versions as they abstract out some platform and or
// compiler version specific functionality
// malloc(0) and realloc(ptr, 0) have implementation-defined behavior in
// that the standard allows them to either return a unique pointer or a
// nullptr for zero-sized allocation requests. Normalize by always using
// a nullptr.
template <typename T>
inline T* UncheckedRealloc(T* pointer, size_t n);
template <typename T>
inline T* UncheckedMalloc(size_t n);
template <typename T>
inline T* UncheckedCalloc(size_t n);
// Same things, but aborts immediately instead of returning nullptr when
// no memory is available.
template <typename T>
inline T* Realloc(T* pointer, size_t n);
template <typename T>
inline T* Malloc(size_t n);
template <typename T>
inline T* Calloc(size_t n);
inline char* Malloc(size_t n);
inline char* Calloc(size_t n);
inline char* UncheckedMalloc(size_t n);
inline char* UncheckedCalloc(size_t n);
// Used by the allocation functions when allocation fails.
// Thin wrapper around v8::Isolate::LowMemoryNotification() that checks
// whether V8 is initialized.
void LowMemoryNotification();
#ifdef __GNUC__
#define NO_RETURN __attribute__((noreturn))
#else
#define NO_RETURN
#endif
// The slightly odd function signature for Assert() is to ease
// instruction cache pressure in calls from CHECK.
NO_RETURN void Abort();
NO_RETURN void Assert(const char* const (*args)[4]);
void DumpBacktrace(FILE* fp);
template <typename T> using remove_reference = std::remove_reference<T>;
#define FIXED_ONE_BYTE_STRING(isolate, string) \
(node::OneByteString((isolate), (string), sizeof(string) - 1))
#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
void operator=(const TypeName&) = delete; \
void operator=(TypeName&&) = delete; \
TypeName(const TypeName&) = delete; \
TypeName(TypeName&&) = delete
// Windows 8+ does not like abort() in Release mode
#ifdef _WIN32
#define ABORT_NO_BACKTRACE() raise(SIGABRT)
#else
#define ABORT_NO_BACKTRACE() abort()
#endif
#define ABORT() node::Abort()
#ifdef __GNUC__
#define LIKELY(expr) __builtin_expect(!!(expr), 1)
#define UNLIKELY(expr) __builtin_expect(!!(expr), 0)
#define PRETTY_FUNCTION_NAME __PRETTY_FUNCTION__
#else
#define LIKELY(expr) expr
#define UNLIKELY(expr) expr
#define PRETTY_FUNCTION_NAME ""
#endif
#define STRINGIFY_(x) #x
#define STRINGIFY(x) STRINGIFY_(x)
#define CHECK(expr) \
do { \
if (UNLIKELY(!(expr))) { \
static const char* const args[] = { __FILE__, STRINGIFY(__LINE__), \
#expr, PRETTY_FUNCTION_NAME }; \
node::Assert(&args); \
} \
} while (0)
#define CHECK_EQ(a, b) CHECK((a) == (b))
#define CHECK_GE(a, b) CHECK((a) >= (b))
#define CHECK_GT(a, b) CHECK((a) > (b))
#define CHECK_LE(a, b) CHECK((a) <= (b))
#define CHECK_LT(a, b) CHECK((a) < (b))
#define CHECK_NE(a, b) CHECK((a) != (b))
#define UNREACHABLE() ABORT()
#define ASSIGN_OR_RETURN_UNWRAP(ptr, obj, ...) \
do { \
*ptr = \
Unwrap<typename node::remove_reference<decltype(**ptr)>::type>(obj); \
if (*ptr == nullptr) \
return __VA_ARGS__; \
} while (0)
// TAILQ-style intrusive list node.
template <typename T>
class ListNode;
// TAILQ-style intrusive list head.
template <typename T, ListNode<T> (T::*M)>
class ListHead;
template <typename T>
class ListNode {
public:
inline ListNode();
inline ~ListNode();
inline void Remove();
inline bool IsEmpty() const;
private:
template <typename U, ListNode<U> (U::*M)> friend class ListHead;
ListNode* prev_;
ListNode* next_;
DISALLOW_COPY_AND_ASSIGN(ListNode);
};
template <typename T, ListNode<T> (T::*M)>
class ListHead {
public:
class Iterator {
public:
inline T* operator*() const;
inline const Iterator& operator++();
inline bool operator!=(const Iterator& that) const;
private:
friend class ListHead;
inline explicit Iterator(ListNode<T>* node);
ListNode<T>* node_;
};
inline ListHead() = default;
inline ~ListHead();
inline void MoveBack(ListHead* that);
inline void PushBack(T* element);
inline void PushFront(T* element);
inline bool IsEmpty() const;
inline T* PopFront();
inline Iterator begin() const;
inline Iterator end() const;
private:
ListNode<T> head_;
DISALLOW_COPY_AND_ASSIGN(ListHead);
};
// The helper is for doing safe downcasts from base types to derived types.
template <typename Inner, typename Outer>
class ContainerOfHelper {
public:
inline ContainerOfHelper(Inner Outer::*field, Inner* pointer);
template <typename TypeName>
inline operator TypeName*() const;
private:
Outer* const pointer_;
};
// Calculate the address of the outer (i.e. embedding) struct from
// the interior pointer to a data member.
template <typename Inner, typename Outer>
inline ContainerOfHelper<Inner, Outer> ContainerOf(Inner Outer::*field,
Inner* pointer);
// If persistent.IsWeak() == false, then do not call persistent.Reset()
// while the returned Local<T> is still in scope, it will destroy the
// reference to the object.
template <class TypeName>
inline v8::Local<TypeName> PersistentToLocal(
v8::Isolate* isolate,
const v8::Persistent<TypeName>& persistent);
// Unchecked conversion from a non-weak Persistent<T> to Local<TLocal<T>,
// use with care!
//
// Do not call persistent.Reset() while the returned Local<T> is still in
// scope, it will destroy the reference to the object.
template <class TypeName>
inline v8::Local<TypeName> StrongPersistentToLocal(
const v8::Persistent<TypeName>& persistent);
template <class TypeName>
inline v8::Local<TypeName> WeakPersistentToLocal(
v8::Isolate* isolate,
const v8::Persistent<TypeName>& persistent);
// Convenience wrapper around v8::String::NewFromOneByte().
inline v8::Local<v8::String> OneByteString(v8::Isolate* isolate,
const char* data,
int length = -1);
// For the people that compile with -funsigned-char.
inline v8::Local<v8::String> OneByteString(v8::Isolate* isolate,
const signed char* data,
int length = -1);
inline v8::Local<v8::String> OneByteString(v8::Isolate* isolate,
const unsigned char* data,
int length = -1);
inline void Wrap(v8::Local<v8::Object> object, void* pointer);
inline void ClearWrap(v8::Local<v8::Object> object);
template <typename TypeName>
inline TypeName* Unwrap(v8::Local<v8::Object> object);
// Swaps bytes in place. nbytes is the number of bytes to swap and must be a
// multiple of the word size (checked by function).
inline void SwapBytes16(char* data, size_t nbytes);
inline void SwapBytes32(char* data, size_t nbytes);
inline void SwapBytes64(char* data, size_t nbytes);
// tolower() is locale-sensitive. Use ToLower() instead.
inline char ToLower(char c);
// strcasecmp() is locale-sensitive. Use StringEqualNoCase() instead.
inline bool StringEqualNoCase(const char* a, const char* b);
// strncasecmp() is locale-sensitive. Use StringEqualNoCaseN() instead.
inline bool StringEqualNoCaseN(const char* a, const char* b, size_t length);
// Allocates an array of member type T. For up to kStackStorageSize items,
// the stack is used, otherwise malloc().
template <typename T, size_t kStackStorageSize = 1024>
class MaybeStackBuffer {
public:
const T* out() const {
return buf_;
}
T* out() {
return buf_;
}
// operator* for compatibility with `v8::String::(Utf8)Value`
T* operator*() {
return buf_;
}
const T* operator*() const {
return buf_;
}
T& operator[](size_t index) {
CHECK_LT(index, length());
return buf_[index];
}
const T& operator[](size_t index) const {
CHECK_LT(index, length());
return buf_[index];
}
size_t length() const {
return length_;
}
// Current maximum capacity of the buffer with which SetLength() can be used
// without first calling AllocateSufficientStorage().
size_t capacity() const {
return IsAllocated() ? capacity_ :
IsInvalidated() ? 0 : kStackStorageSize;
}
// Make sure enough space for `storage` entries is available.
// This method can be called multiple times throughout the lifetime of the
// buffer, but once this has been called Invalidate() cannot be used.
// Content of the buffer in the range [0, length()) is preserved.
void AllocateSufficientStorage(size_t storage) {
CHECK(!IsInvalidated());
if (storage > capacity()) {
bool was_allocated = IsAllocated();
T* allocated_ptr = was_allocated ? buf_ : nullptr;
buf_ = Realloc(allocated_ptr, storage);
capacity_ = storage;
if (!was_allocated && length_ > 0)
memcpy(buf_, buf_st_, length_ * sizeof(buf_[0]));
}
length_ = storage;
}
void SetLength(size_t length) {
// capacity() returns how much memory is actually available.
CHECK_LE(length, capacity());
length_ = length;
}
void SetLengthAndZeroTerminate(size_t length) {
// capacity() returns how much memory is actually available.
CHECK_LE(length + 1, capacity());
SetLength(length);
// T() is 0 for integer types, nullptr for pointers, etc.
buf_[length] = T();
}
// Make derefencing this object return nullptr.
// This method can be called multiple times throughout the lifetime of the
// buffer, but once this has been called AllocateSufficientStorage() cannot
// be used.
void Invalidate() {
CHECK(!IsAllocated());
length_ = 0;
buf_ = nullptr;
}
// If the buffer is stored in the heap rather than on the stack.
bool IsAllocated() const {
return !IsInvalidated() && buf_ != buf_st_;
}
// If Invalidate() has been called.
bool IsInvalidated() const {
return buf_ == nullptr;
}
// Release ownership of the malloc'd buffer.
// Note: This does not free the buffer.
void Release() {
CHECK(IsAllocated());
buf_ = buf_st_;
length_ = 0;
capacity_ = 0;
}
MaybeStackBuffer() : length_(0), capacity_(0), buf_(buf_st_) {
// Default to a zero-length, null-terminated buffer.
buf_[0] = T();
}
explicit MaybeStackBuffer(size_t storage) : MaybeStackBuffer() {
AllocateSufficientStorage(storage);
}
~MaybeStackBuffer() {
if (IsAllocated())
free(buf_);
}
private:
size_t length_;
// capacity of the malloc'ed buf_
size_t capacity_;
T* buf_;
T buf_st_[kStackStorageSize];
};
class Utf8Value : public MaybeStackBuffer<char> {
public:
explicit Utf8Value(v8::Isolate* isolate, v8::Local<v8::Value> value);
};
class TwoByteValue : public MaybeStackBuffer<uint16_t> {
public:
explicit TwoByteValue(v8::Isolate* isolate, v8::Local<v8::Value> value);
};
class BufferValue : public MaybeStackBuffer<char> {
public:
explicit BufferValue(v8::Isolate* isolate, v8::Local<v8::Value> value);
};
#define THROW_AND_RETURN_UNLESS_BUFFER(env, obj) \
do { \
if (!Buffer::HasInstance(obj)) \
return env->ThrowTypeError("argument should be a Buffer"); \
} while (0)
#define SPREAD_BUFFER_ARG(val, name) \
CHECK((val)->IsArrayBufferView()); \
v8::Local<v8::ArrayBufferView> name = (val).As<v8::ArrayBufferView>(); \
v8::ArrayBuffer::Contents name##_c = name->Buffer()->GetContents(); \
const size_t name##_offset = name->ByteOffset(); \
const size_t name##_length = name->ByteLength(); \
char* const name##_data = \
static_cast<char*>(name##_c.Data()) + name##_offset; \
if (name##_length > 0) \
CHECK_NE(name##_data, nullptr);
} // namespace node
#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#endif // SRC_UTIL_H_
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