lts/src/util.h
// 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
#if (__GNUC__ >= 8) && !defined(__clang__)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-function-type"
#endif
#include "v8.h"
#if (__GNUC__ >= 8) && !defined(__clang__)
#pragma GCC diagnostic pop
#endif
#include <climits>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional> // std::function
#include <limits>
#include <set>
#include <string>
#include <array>
#include <unordered_map>
#include <utility>
#ifdef __GNUC__
#define MUST_USE_RESULT __attribute__((warn_unused_result))
#else
#define MUST_USE_RESULT
#endif
namespace node {
// Maybe remove kPathSeparator when cpp17 is ready
#ifdef _WIN32
constexpr char kPathSeparator = '\\';
/* MAX_PATH is in characters, not bytes. Make sure we have enough headroom. */
#define PATH_MAX_BYTES (MAX_PATH * 4)
#else
constexpr char kPathSeparator = '/';
#define PATH_MAX_BYTES (PATH_MAX)
#endif
// 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);
template <typename T>
inline T MultiplyWithOverflowCheck(T a, T b);
namespace per_process {
// Tells whether the per-process V8::Initialize() is called and
// if it is safe to call v8::Isolate::GetCurrent().
extern bool v8_initialized;
} // namespace per_process
// Used by the allocation functions when allocation fails.
// Thin wrapper around v8::Isolate::LowMemoryNotification() that checks
// whether V8 is initialized.
void LowMemoryNotification();
// The reason that Assert() takes a struct argument instead of individual
// const char*s is to ease instruction cache pressure in calls from CHECK.
struct AssertionInfo {
const char* file_line; // filename:line
const char* message;
const char* function;
};
[[noreturn]] void Assert(const AssertionInfo& info);
[[noreturn]] void Abort();
void DumpBacktrace(FILE* fp);
// Windows 8+ does not like abort() in Release mode
#ifdef _WIN32
#define ABORT_NO_BACKTRACE() _exit(134)
#else
#define ABORT_NO_BACKTRACE() abort()
#endif
#define ABORT() node::Abort()
#define ERROR_AND_ABORT(expr) \
do { \
/* Make sure that this struct does not end up in inline code, but */ \
/* rather in a read-only data section when modifying this code. */ \
static const node::AssertionInfo args = { \
__FILE__ ":" STRINGIFY(__LINE__), #expr, PRETTY_FUNCTION_NAME \
}; \
node::Assert(args); \
} while (0)
#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))) { \
ERROR_AND_ABORT(expr); \
} \
} 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 CHECK_NULL(val) CHECK((val) == nullptr)
#define CHECK_NOT_NULL(val) CHECK((val) != nullptr)
#define CHECK_IMPLIES(a, b) CHECK(!(a) || (b))
#ifdef DEBUG
#define DCHECK(expr) CHECK(expr)
#define DCHECK_EQ(a, b) CHECK((a) == (b))
#define DCHECK_GE(a, b) CHECK((a) >= (b))
#define DCHECK_GT(a, b) CHECK((a) > (b))
#define DCHECK_LE(a, b) CHECK((a) <= (b))
#define DCHECK_LT(a, b) CHECK((a) < (b))
#define DCHECK_NE(a, b) CHECK((a) != (b))
#define DCHECK_NULL(val) CHECK((val) == nullptr)
#define DCHECK_NOT_NULL(val) CHECK((val) != nullptr)
#define DCHECK_IMPLIES(a, b) CHECK(!(a) || (b))
#else
#define DCHECK(expr)
#define DCHECK_EQ(a, b)
#define DCHECK_GE(a, b)
#define DCHECK_GT(a, b)
#define DCHECK_LE(a, b)
#define DCHECK_LT(a, b)
#define DCHECK_NE(a, b)
#define DCHECK_NULL(val)
#define DCHECK_NOT_NULL(val)
#define DCHECK_IMPLIES(a, b)
#endif
#define UNREACHABLE(...) \
ERROR_AND_ABORT("Unreachable code reached" __VA_OPT__(": ") __VA_ARGS__)
// 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;
ListNode(const ListNode&) = delete;
ListNode& operator=(const ListNode&) = delete;
private:
template <typename U, ListNode<U> (U::*M)> friend class ListHead;
friend int GenDebugSymbols();
ListNode* prev_;
ListNode* next_;
};
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 PushBack(T* element);
inline void PushFront(T* element);
inline bool IsEmpty() const;
inline T* PopFront();
inline Iterator begin() const;
inline Iterator end() const;
ListHead(const ListHead&) = delete;
ListHead& operator=(const ListHead&) = delete;
private:
friend int GenDebugSymbols();
ListNode<T> head_;
};
// 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>
constexpr ContainerOfHelper<Inner, Outer> ContainerOf(Inner Outer::*field,
Inner* pointer);
// 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);
// Used to be a macro, hence the uppercase name.
template <int N>
inline v8::Local<v8::String> FIXED_ONE_BYTE_STRING(
v8::Isolate* isolate,
const char(&data)[N]) {
return OneByteString(isolate, data, N - 1);
}
template <std::size_t N>
inline v8::Local<v8::String> FIXED_ONE_BYTE_STRING(
v8::Isolate* isolate,
const std::array<char, N>& arr) {
return OneByteString(isolate, arr.data(), N - 1);
}
// 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);
inline std::string ToLower(const std::string& in);
// toupper() is locale-sensitive. Use ToUpper() instead.
inline char ToUpper(char c);
inline std::string ToUpper(const std::string& in);
// 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);
template <typename T, size_t N>
constexpr size_t arraysize(const T (&)[N]) {
return N;
}
// 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 capacity_;
}
// 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());
capacity_ = 0;
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_ = arraysize(buf_st_);
}
MaybeStackBuffer()
: length_(0), capacity_(arraysize(buf_st_)), 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];
};
// Provides access to an ArrayBufferView's storage, either the original,
// or for small data, a copy of it. This object's lifetime is bound to the
// original ArrayBufferView's lifetime.
template <typename T, size_t kStackStorageSize = 64>
class ArrayBufferViewContents {
public:
ArrayBufferViewContents() = default;
explicit inline ArrayBufferViewContents(v8::Local<v8::Value> value);
explicit inline ArrayBufferViewContents(v8::Local<v8::Object> value);
explicit inline ArrayBufferViewContents(v8::Local<v8::ArrayBufferView> abv);
inline void Read(v8::Local<v8::ArrayBufferView> abv);
inline const T* data() const { return data_; }
inline size_t length() const { return length_; }
private:
T stack_storage_[kStackStorageSize];
T* data_ = nullptr;
size_t length_ = 0;
};
class Utf8Value : public MaybeStackBuffer<char> {
public:
explicit Utf8Value(v8::Isolate* isolate, v8::Local<v8::Value> value);
inline std::string ToString() const { return std::string(out(), length()); }
};
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);
inline std::string ToString() const { return std::string(out(), length()); }
};
#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);
// Use this when a variable or parameter is unused in order to explicitly
// silence a compiler warning about that.
template <typename T> inline void USE(T&&) {}
template <typename Fn>
struct OnScopeLeaveImpl {
Fn fn_;
bool active_;
explicit OnScopeLeaveImpl(Fn&& fn) : fn_(std::move(fn)), active_(true) {}
~OnScopeLeaveImpl() { if (active_) fn_(); }
OnScopeLeaveImpl(const OnScopeLeaveImpl& other) = delete;
OnScopeLeaveImpl& operator=(const OnScopeLeaveImpl& other) = delete;
OnScopeLeaveImpl(OnScopeLeaveImpl&& other)
: fn_(std::move(other.fn_)), active_(other.active_) {
other.active_ = false;
}
OnScopeLeaveImpl& operator=(OnScopeLeaveImpl&& other) {
if (this == &other) return *this;
this->~OnScopeLeave();
new (this)OnScopeLeaveImpl(std::move(other));
return *this;
}
};
// Run a function when exiting the current scope. Used like this:
// auto on_scope_leave = OnScopeLeave([&] {
// // ... run some code ...
// });
template <typename Fn>
inline MUST_USE_RESULT OnScopeLeaveImpl<Fn> OnScopeLeave(Fn&& fn) {
return OnScopeLeaveImpl<Fn>{std::move(fn)};
}
// Simple RAII wrapper for contiguous data that uses malloc()/free().
template <typename T>
struct MallocedBuffer {
T* data;
size_t size;
T* release() {
T* ret = data;
data = nullptr;
return ret;
}
void Truncate(size_t new_size) {
CHECK(new_size <= size);
size = new_size;
}
inline bool is_empty() const { return data == nullptr; }
MallocedBuffer() : data(nullptr), size(0) {}
explicit MallocedBuffer(size_t size) : data(Malloc<T>(size)), size(size) {}
MallocedBuffer(T* data, size_t size) : data(data), size(size) {}
MallocedBuffer(MallocedBuffer&& other) : data(other.data), size(other.size) {
other.data = nullptr;
}
MallocedBuffer& operator=(MallocedBuffer&& other) {
this->~MallocedBuffer();
return *new(this) MallocedBuffer(std::move(other));
}
~MallocedBuffer() {
free(data);
}
MallocedBuffer(const MallocedBuffer&) = delete;
MallocedBuffer& operator=(const MallocedBuffer&) = delete;
};
template <typename T>
class NonCopyableMaybe {
public:
NonCopyableMaybe() : empty_(true) {}
explicit NonCopyableMaybe(T&& value)
: empty_(false),
value_(std::move(value)) {}
bool IsEmpty() const {
return empty_;
}
T&& Release() {
CHECK_EQ(empty_, false);
empty_ = true;
return std::move(value_);
}
private:
bool empty_;
T value_;
};
// Test whether some value can be called with ().
template <typename T, typename = void>
struct is_callable : std::is_function<T> { };
template <typename T>
struct is_callable<T, typename std::enable_if<
std::is_same<decltype(void(&T::operator())), void>::value
>::type> : std::true_type { };
template <typename T, void (*function)(T*)>
struct FunctionDeleter {
void operator()(T* pointer) const { function(pointer); }
typedef std::unique_ptr<T, FunctionDeleter> Pointer;
};
template <typename T, void (*function)(T*)>
using DeleteFnPtr = typename FunctionDeleter<T, function>::Pointer;
std::vector<std::string> SplitString(const std::string& in, char delim);
inline v8::MaybeLocal<v8::Value> ToV8Value(v8::Local<v8::Context> context,
const std::string& str,
v8::Isolate* isolate = nullptr);
template <typename T, typename test_for_number =
typename std::enable_if<std::numeric_limits<T>::is_specialized, bool>::type>
inline v8::MaybeLocal<v8::Value> ToV8Value(v8::Local<v8::Context> context,
const T& number,
v8::Isolate* isolate = nullptr);
template <typename T>
inline v8::MaybeLocal<v8::Value> ToV8Value(v8::Local<v8::Context> context,
const std::vector<T>& vec,
v8::Isolate* isolate = nullptr);
template <typename T, typename U>
inline v8::MaybeLocal<v8::Value> ToV8Value(v8::Local<v8::Context> context,
const std::unordered_map<T, U>& map,
v8::Isolate* isolate = nullptr);
// These macros expects a `Isolate* isolate` and a `Local<Context> context`
// to be in the scope.
#define READONLY_PROPERTY(obj, name, value) \
do { \
obj->DefineOwnProperty( \
context, FIXED_ONE_BYTE_STRING(isolate, name), value, v8::ReadOnly) \
.Check(); \
} while (0)
#define READONLY_DONT_ENUM_PROPERTY(obj, name, var) \
do { \
obj->DefineOwnProperty( \
context, \
OneByteString(isolate, name), \
var, \
static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontEnum)) \
.Check(); \
} while (0)
#define READONLY_FALSE_PROPERTY(obj, name) \
READONLY_PROPERTY(obj, name, v8::False(isolate))
#define READONLY_TRUE_PROPERTY(obj, name) \
READONLY_PROPERTY(obj, name, v8::True(isolate))
#define READONLY_STRING_PROPERTY(obj, name, str) \
READONLY_PROPERTY(obj, name, ToV8Value(context, str).ToLocalChecked())
// Variation on NODE_DEFINE_CONSTANT that sets a String value.
#define NODE_DEFINE_STRING_CONSTANT(target, name, constant) \
do { \
v8::Isolate* isolate = target->GetIsolate(); \
v8::Local<v8::String> constant_name = \
v8::String::NewFromUtf8(isolate, name, v8::NewStringType::kNormal) \
.ToLocalChecked(); \
v8::Local<v8::String> constant_value = \
v8::String::NewFromUtf8(isolate, constant, v8::NewStringType::kNormal) \
.ToLocalChecked(); \
v8::PropertyAttribute constant_attributes = \
static_cast<v8::PropertyAttribute>(v8::ReadOnly | v8::DontDelete); \
target \
->DefineOwnProperty(isolate->GetCurrentContext(), \
constant_name, \
constant_value, \
constant_attributes) \
.Check(); \
} while (0)
enum Endianness {
kLittleEndian, // _Not_ LITTLE_ENDIAN, clashes with endian.h.
kBigEndian
};
inline enum Endianness GetEndianness() {
// Constant-folded by the compiler.
const union {
uint8_t u8[2];
uint16_t u16;
} u = {{1, 0}};
return u.u16 == 1 ? kLittleEndian : kBigEndian;
}
inline bool IsLittleEndian() {
return GetEndianness() == kLittleEndian;
}
inline bool IsBigEndian() {
return GetEndianness() == kBigEndian;
}
// Round up a to the next highest multiple of b.
template <typename T>
constexpr T RoundUp(T a, T b) {
return a % b != 0 ? a + b - (a % b) : a;
}
class SlicedArguments : public MaybeStackBuffer<v8::Local<v8::Value>> {
public:
inline explicit SlicedArguments(
const v8::FunctionCallbackInfo<v8::Value>& args, size_t start = 0);
};
// Convert a v8::PersistentBase, e.g. v8::Global, to a Local, with an extra
// optimization for strong persistent handles.
class PersistentToLocal {
public:
// 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>
static inline v8::Local<TypeName> Default(
v8::Isolate* isolate,
const v8::PersistentBase<TypeName>& persistent) {
if (persistent.IsWeak()) {
return PersistentToLocal::Weak(isolate, persistent);
} else {
return PersistentToLocal::Strong(persistent);
}
}
// Unchecked conversion from a non-weak Persistent<T> to Local<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>
static inline v8::Local<TypeName> Strong(
const v8::PersistentBase<TypeName>& persistent) {
return *reinterpret_cast<v8::Local<TypeName>*>(
const_cast<v8::PersistentBase<TypeName>*>(&persistent));
}
template <class TypeName>
static inline v8::Local<TypeName> Weak(
v8::Isolate* isolate,
const v8::PersistentBase<TypeName>& persistent) {
return v8::Local<TypeName>::New(isolate, persistent);
}
};
} // namespace node
#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
#endif // SRC_UTIL_H_