react-native/ReactCommon/jschelpers/Value.h

347 lines
9.4 KiB
C++

// Copyright 2004-present Facebook. All Rights Reserved.
#pragma once
#include <memory>
#include <sstream>
#include <unordered_map>
#include <vector>
#include <folly/dynamic.h>
#include <jschelpers/JavaScriptCore.h>
#include <jschelpers/Unicode.h>
#include <jschelpers/noncopyable.h>
#ifndef RN_EXPORT
#define RN_EXPORT __attribute__((visibility("default")))
#endif
namespace facebook {
namespace react {
class Value;
// C++ object wrapper for JSStringRef
class String : public noncopyable {
public:
explicit String(): m_context(nullptr), m_string(nullptr) {} // dummy empty constructor
explicit String(JSContextRef context, const char* utf8)
: m_context(context), m_string(JSC_JSStringCreateWithUTF8CString(context, utf8)) {}
String(String&& other) :
m_context(other.m_context), m_string(other.m_string)
{
other.m_string = nullptr;
}
String(const String& other) :
m_context(other.m_context), m_string(other.m_string)
{
if (m_string) {
JSC_JSStringRetain(m_context, m_string);
}
}
~String() {
if (m_string) {
JSC_JSStringRelease(m_context, m_string);
}
}
String& operator=(String&& other) {
if (m_string) {
JSC_JSStringRelease(m_context, m_string);
}
m_context = other.m_context;
m_string = other.m_string;
other.m_string = nullptr;
return *this;
}
operator JSStringRef() const {
return m_string;
}
JSContextRef context() const {
return m_context;
}
// Length in characters
size_t length() const {
return m_string ? JSC_JSStringGetLength(m_context, m_string) : 0;
}
// Length in bytes of a nul-terminated utf8 encoded value
size_t utf8Size() const {
return m_string ? JSC_JSStringGetMaximumUTF8CStringSize(m_context, m_string) : 0;
}
/*
* JavaScriptCore is built with strict utf16 -> utf8 conversion.
* This means if JSC's built-in conversion function encounters a JavaScript
* string which contains half of a 32-bit UTF-16 symbol, it produces an error
* rather than returning a string.
*
* Instead of relying on this, we use our own utf16 -> utf8 conversion function
* which is more lenient and always returns a string. When an invalid UTF-16
* string is provided, it'll likely manifest as a rendering glitch in the app for
* the invalid symbol.
*
* For details on JavaScript's unicode support see:
* https://mathiasbynens.be/notes/javascript-unicode
*/
std::string str() const {
if (!m_string) {
return "";
}
const JSChar* utf16 = JSC_JSStringGetCharactersPtr(m_context, m_string);
size_t stringLength = JSC_JSStringGetLength(m_context, m_string);
return unicode::utf16toUTF8(utf16, stringLength);
}
// Assumes that utf8 is nul-terminated
bool equals(const char* utf8) {
return m_string ? JSC_JSStringIsEqualToUTF8CString(m_context, m_string, utf8) : false;
}
// This assumes ascii is nul-terminated.
static String createExpectingAscii(JSContextRef context, const char* ascii, size_t len) {
#if WITH_FBJSCEXTENSIONS
return String(context, JSC_JSStringCreateWithUTF8CStringExpectAscii(context, ascii, len), true);
#else
return String(context, JSC_JSStringCreateWithUTF8CString(context, ascii), true);
#endif
}
static String createExpectingAscii(JSContextRef context, std::string const &ascii) {
return createExpectingAscii(context, ascii.c_str(), ascii.size());
}
// Creates a String wrapper and increases the refcount of the JSStringRef
static String ref(JSContextRef context, JSStringRef string) {
return String(context, string, false);
}
// Creates a String wrapper that takes over ownership of the string. The
// JSStringRef passed in must previously have been created or retained.
static String adopt(JSContextRef context, JSStringRef string) {
return String(context, string, true);
}
private:
explicit String(JSContextRef context, JSStringRef string, bool adopt) :
m_context(context), m_string(string)
{
if (!adopt && string) {
JSC_JSStringRetain(context, string);
}
}
JSContextRef m_context;
JSStringRef m_string;
};
// C++ object wrapper for JSObjectRef. The underlying JSObjectRef can be
// optionally protected. You must protect the object if it is ever
// heap-allocated, since otherwise you may end up with an invalid reference.
class Object : public noncopyable {
public:
Object(JSContextRef context, JSObjectRef obj) :
m_context(context),
m_obj(obj)
{}
Object(Object&& other) :
m_context(other.m_context),
m_obj(other.m_obj),
m_isProtected(other.m_isProtected) {
other.m_obj = nullptr;
other.m_isProtected = false;
}
~Object() {
if (m_isProtected && m_obj) {
JSC_JSValueUnprotect(m_context, m_obj);
}
}
Object& operator=(Object&& other) {
std::swap(m_context, other.m_context);
std::swap(m_obj, other.m_obj);
std::swap(m_isProtected, other.m_isProtected);
return *this;
}
operator JSObjectRef() const {
return m_obj;
}
operator Value() const;
bool isFunction() const {
return JSC_JSObjectIsFunction(m_context, m_obj);
}
Value callAsFunction(std::initializer_list<JSValueRef> args) const;
Value callAsFunction(const Object& thisObj, std::initializer_list<JSValueRef> args) const;
Value callAsFunction(int nArgs, const JSValueRef args[]) const;
Value callAsFunction(const Object& thisObj, int nArgs, const JSValueRef args[]) const;
Object callAsConstructor(std::initializer_list<JSValueRef> args) const;
Value getProperty(const String& propName) const;
Value getProperty(const char *propName) const;
Value getPropertyAtIndex(unsigned int index) const;
void setProperty(const String& propName, const Value& value);
void setProperty(const char *propName, const Value& value);
void setPropertyAtIndex(unsigned int index, const Value& value);
std::vector<String> getPropertyNames() const;
std::unordered_map<std::string, std::string> toJSONMap() const;
void makeProtected() {
if (!m_isProtected && m_obj) {
JSC_JSValueProtect(m_context, m_obj);
m_isProtected = true;
}
}
template<typename ReturnType>
ReturnType* getPrivate() const {
const bool isCustomJSC = isCustomJSCPtr(m_context);
return static_cast<ReturnType*>(JSC_JSObjectGetPrivate(isCustomJSC, m_obj));
}
void setPrivate(void* data) const {
const bool isCustomJSC = isCustomJSCPtr(m_context);
JSC_JSObjectSetPrivate(isCustomJSC, m_obj, data);
}
JSContextRef context() const {
return m_context;
}
static Object getGlobalObject(JSContextRef ctx) {
auto globalObj = JSC_JSContextGetGlobalObject(ctx);
return Object(ctx, globalObj);
}
/**
* Creates an instance of the default object class.
*/
static Object create(JSContextRef ctx);
private:
JSContextRef m_context;
JSObjectRef m_obj;
bool m_isProtected = false;
Value callAsFunction(JSObjectRef thisObj, int nArgs, const JSValueRef args[]) const;
};
// C++ object wrapper for JSValueRef. The underlying JSValueRef is not
// protected, so this class should always be used as a stack-allocated
// variable.
class Value : public noncopyable {
public:
RN_EXPORT Value(JSContextRef context, JSValueRef value);
RN_EXPORT Value(JSContextRef context, JSStringRef value);
RN_EXPORT Value(const Value &o) : Value(o.m_context, o.m_value) {}
RN_EXPORT Value(const String &o) : Value(o.context(), o) {}
Value& operator=(Value&& other) {
m_context = other.m_context;
m_value = other.m_value;
other.m_value = NULL;
return *this;
};
operator JSValueRef() const {
return m_value;
}
JSType getType() const {
return JSC_JSValueGetType(m_context, m_value);
}
bool isBoolean() const {
return getType() == kJSTypeBoolean;
}
bool asBoolean() const {
return JSC_JSValueToBoolean(context(), m_value);
}
bool isNumber() const {
return getType() == kJSTypeNumber;
}
bool isNull() const {
return getType() == kJSTypeNull;
}
bool isUndefined() const {
return getType() == kJSTypeUndefined;
}
double asNumber() const {
if (isNumber()) {
return JSC_JSValueToNumber(context(), m_value, nullptr);
} else {
return 0.0f;
}
}
int32_t asInteger() const {
return static_cast<int32_t>(asNumber());
}
uint32_t asUnsignedInteger() const {
return static_cast<uint32_t>(asNumber());
}
bool isObject() const {
return getType() == kJSTypeObject;
}
RN_EXPORT Object asObject() const;
bool isString() const {
return getType() == kJSTypeString;
}
RN_EXPORT String toString() const;
// Create an error, optionally adding an additional number of lines to the stack.
// Stack must be empty or newline terminated.
RN_EXPORT static Value makeError(JSContextRef ctx, const char *error, const char *stack = nullptr);
static Value makeNumber(JSContextRef ctx, double value) {
return Value(ctx, JSC_JSValueMakeNumber(ctx, value));
}
static Value makeUndefined(JSContextRef ctx) {
return Value(ctx, JSC_JSValueMakeUndefined(ctx));
}
static Value makeNull(JSContextRef ctx) {
return Value(ctx, JSC_JSValueMakeNull(ctx));
}
RN_EXPORT std::string toJSONString(unsigned indent = 0) const;
RN_EXPORT static Value fromJSON(const String& json);
RN_EXPORT static Value fromDynamic(JSContextRef ctx, const folly::dynamic& value);
RN_EXPORT JSContextRef context() const;
private:
JSContextRef m_context;
JSValueRef m_value;
static JSValueRef fromDynamicInner(JSContextRef ctx, const folly::dynamic& obj);
};
} }