react-native/ReactCommon/jschelpers/Value.cpp

326 lines
11 KiB
C++
Raw Normal View History

// Copyright (c) Facebook, Inc. and its affiliates.
// This source code is licensed under the MIT license found in the
// LICENSE file in the root directory of this source tree.
#include "Value.h"
#include <folly/json.h>
#include <folly/Conv.h>
#include "JSCHelpers.h"
#include "JavaScriptCore.h"
// See the comment under Value::fromDynamic()
#if !defined(__APPLE__) && defined(WITH_FB_JSC_TUNING)
#define USE_FAST_FOLLY_DYNAMIC_CONVERSION 1
#else
#define USE_FAST_FOLLY_DYNAMIC_CONVERSION 0
#endif
namespace facebook {
namespace react {
/* static */
Object Object::makeDate(JSContextRef ctx, Object::TimeType time) {
using std::chrono::duration_cast;
using std::chrono::milliseconds;
JSValueRef arguments[1];
arguments[0] = JSC_JSValueMakeNumber(
ctx,
duration_cast<milliseconds>(time.time_since_epoch()).count());
JSValueRef exn;
auto result = JSC_JSObjectMakeDate(ctx, 1, arguments, &exn);
if (!result) {
throw JSException(ctx, exn, "Failed to create Date");
}
return Object(ctx, result);
}
Object Object::makeArray(JSContextRef ctx, JSValueRef* elements, unsigned length) {
JSValueRef exn;
auto arr = JSC_JSObjectMakeArray(ctx, length, elements, &exn);
if (!arr) {
throw JSException(ctx, exn, "Failed to create an Array");
}
return Object(ctx, arr);
}
Value::Value(JSContextRef context, JSValueRef value)
: m_context(context), m_value(value) {}
Value::Value(JSContextRef context, JSStringRef str)
: m_context(context), m_value(JSC_JSValueMakeString(context, str)) {}
JSContextRef Value::context() const {
return m_context;
}
/* static */
std::string Value::toJSONString(unsigned indent) const {
JSValueRef exn;
auto stringToAdopt = JSC_JSValueCreateJSONString(m_context, m_value, indent, &exn);
if (!stringToAdopt) {
throw JSException(m_context, exn, "Exception creating JSON string");
}
return String::adopt(m_context, stringToAdopt).str();
}
/* static */
Value Value::fromJSON(const String& json) {
JSContextRef ctx = json.context();
auto result = JSC_JSValueMakeFromJSONString(ctx, json);
if (!result) {
throw JSException(folly::to<std::string>(
"Failed to create Value from JSON: ", json.str()).c_str());
}
return Value(ctx, result);
}
Value Value::fromDynamic(JSContextRef ctx, const folly::dynamic& value) {
// JavaScriptCore's iOS APIs have their own version of this direct conversion.
// In addition, using this requires exposing some of JSC's private APIs,
// so it's limited to non-apple platforms and to builds that use the custom JSC.
// Otherwise, we use the old way of converting through JSON.
#if USE_FAST_FOLLY_DYNAMIC_CONVERSION
// Defer GC during the creation of the JSValue, as we don't want
// intermediate objects to be collected.
// We could use JSValueProtect(), but it will make the process much slower.
JSDeferredGCRef deferGC = JSDeferGarbageCollection(ctx);
// Set a global lock for the whole process,
// instead of re-acquiring the lock for each operation.
JSLock(ctx);
JSValueRef jsVal = Value::fromDynamicInner(ctx, value);
JSUnlock(ctx);
JSResumeGarbageCollection(ctx, deferGC);
return Value(ctx, jsVal);
#else
auto json = folly::toJson(value);
return fromJSON(String(ctx, json.c_str()));
#endif
}
JSValueRef Value::fromDynamicInner(JSContextRef ctx, const folly::dynamic& obj) {
switch (obj.type()) {
// For primitive types (and strings), just create and return an equivalent JSValue
case folly::dynamic::Type::NULLT:
return JSC_JSValueMakeNull(ctx);
case folly::dynamic::Type::BOOL:
return JSC_JSValueMakeBoolean(ctx, obj.getBool());
case folly::dynamic::Type::DOUBLE:
return JSC_JSValueMakeNumber(ctx, obj.getDouble());
case folly::dynamic::Type::INT64:
return JSC_JSValueMakeNumber(ctx, obj.asDouble());
case folly::dynamic::Type::STRING:
return JSC_JSValueMakeString(ctx, String(ctx, obj.getString().c_str()));
case folly::dynamic::Type::ARRAY: {
// Collect JSValue for every element in the array
JSValueRef vals[obj.size()];
for (size_t i = 0; i < obj.size(); ++i) {
vals[i] = fromDynamicInner(ctx, obj[i]);
}
// Create a JSArray with the values
JSValueRef arr = JSC_JSObjectMakeArray(ctx, obj.size(), vals, nullptr);
return arr;
}
case folly::dynamic::Type::OBJECT: {
// Create an empty object
JSObjectRef jsObj = JSC_JSObjectMake(ctx, nullptr, nullptr);
// Create a JSValue for each of the object's children and set them in the object
for (auto it = obj.items().begin(); it != obj.items().end(); ++it) {
JSC_JSObjectSetProperty(
ctx,
jsObj,
String(ctx, it->first.asString().c_str()),
fromDynamicInner(ctx, it->second),
kJSPropertyAttributeNone,
nullptr);
}
return jsObj;
}
default:
// Assert not reached
LOG(FATAL) << "Trying to convert a folly object of unsupported type.";
return JSC_JSValueMakeNull(ctx);
}
}
Object Value::asObject() const {
JSValueRef exn;
JSObjectRef jsObj = JSC_JSValueToObject(context(), m_value, &exn);
if (!jsObj) {
throw JSException(m_context, exn, "Failed to convert to object");
}
return Object(context(), jsObj);
}
String Value::toString() const {
JSValueRef exn;
JSStringRef jsStr = JSC_JSValueToStringCopy(context(), m_value, &exn);
if (!jsStr) {
throw JSException(m_context, exn, "Failed to convert to string");
}
return String::adopt(context(), jsStr);
}
Value Value::makeError(JSContextRef ctx, const char *error, const char *stack)
{
auto errorMsg = Value(ctx, String(ctx, error));
JSValueRef args[] = {errorMsg};
if (stack) {
// Using this instead of JSObjectMakeError to actually get a stack property.
// MakeError only sets it stack when returning from the invoked function, so we
// can't extend it here.
auto errorConstructor = Object::getGlobalObject(ctx).getProperty("Error").asObject();
auto jsError = errorConstructor.callAsConstructor({errorMsg});
auto fullStack = std::string(stack) + jsError.getProperty("stack").toString().str();
jsError.setProperty("stack", String(ctx, fullStack.c_str()));
return jsError;
} else {
JSValueRef exn;
JSObjectRef errorObj = JSC_JSObjectMakeError(ctx, 1, args, &exn);
if (!errorObj) {
throw JSException(ctx, exn, "Exception making error");
}
return Value(ctx, errorObj);
}
}
void Value::throwTypeException(const std::string &expectedType) const {
std::string wat("TypeError: Expected ");
wat += expectedType;
wat += ", instead got '";
wat += toString().str();
wat += "'";
throw JSException(wat.c_str());
}
Object::operator Value() const {
return Value(m_context, m_obj);
}
Value Object::callAsFunction(std::initializer_list<JSValueRef> args) const {
return callAsFunction(nullptr, args.size(), args.begin());
}
Value Object::callAsFunction(const Object& thisObj, std::initializer_list<JSValueRef> args) const {
return callAsFunction((JSObjectRef)thisObj, args.size(), args.begin());
}
Value Object::callAsFunction(int nArgs, const JSValueRef args[]) const {
return callAsFunction(nullptr, nArgs, args);
}
Value Object::callAsFunction(const Object& thisObj, int nArgs, const JSValueRef args[]) const {
return callAsFunction(static_cast<JSObjectRef>(thisObj), nArgs, args);
}
Value Object::callAsFunction(JSObjectRef thisObj, int nArgs, const JSValueRef args[]) const {
JSValueRef exn;
JSValueRef result = JSC_JSObjectCallAsFunction(m_context, m_obj, thisObj, nArgs, args, &exn);
if (!result) {
throw JSException(m_context, exn, "Exception calling object as function");
}
return Value(m_context, result);
}
Object Object::callAsConstructor(std::initializer_list<JSValueRef> args) const {
JSValueRef exn;
JSObjectRef result = JSC_JSObjectCallAsConstructor(m_context, m_obj, args.size(), args.begin(), &exn);
if (!result) {
throw JSException(m_context, exn, "Exception calling object as constructor");
}
return Object(m_context, result);
}
Value Object::getProperty(const String& propName) const {
JSValueRef exn;
JSValueRef property = JSC_JSObjectGetProperty(m_context, m_obj, propName, &exn);
if (!property) {
throw JSException(m_context, exn, folly::to<std::string>(
"Failed to get property '", propName.str(), "'").c_str());
}
return Value(m_context, property);
}
Value Object::getPropertyAtIndex(unsigned int index) const {
JSValueRef exn;
JSValueRef property = JSC_JSObjectGetPropertyAtIndex(m_context, m_obj, index, &exn);
if (!property) {
throw JSException(m_context, exn, folly::to<std::string>(
"Failed to get property at index ", index).c_str());
}
return Value(m_context, property);
}
Value Object::getProperty(const char *propName) const {
return getProperty(String(m_context, propName));
}
void Object::setProperty(const String& propName, const Value& value) {
JSValueRef exn = nullptr;
JSC_JSObjectSetProperty(m_context, m_obj, propName, value, kJSPropertyAttributeNone, &exn);
if (exn) {
throw JSException(m_context, exn, folly::to<std::string>(
"Failed to set property '", propName.str(), "'").c_str());
}
}
void Object::setPropertyAtIndex(unsigned int index, const Value& value) {
JSValueRef exn = nullptr;
JSC_JSObjectSetPropertyAtIndex(m_context, m_obj, index, value, &exn);
if (exn) {
throw JSException(m_context, exn, folly::to<std::string>(
"Failed to set property at index ", index).c_str());
}
}
void Object::setProperty(const char *propName, const Value& value) {
setProperty(String(m_context, propName), value);
}
std::vector<String> Object::getPropertyNames() const {
auto namesRef = JSC_JSObjectCopyPropertyNames(m_context, m_obj);
size_t count = JSC_JSPropertyNameArrayGetCount(m_context, namesRef);
std::vector<String> names;
names.reserve(count);
for (size_t i = 0; i < count; i++) {
names.emplace_back(String::ref(m_context,
JSC_JSPropertyNameArrayGetNameAtIndex(m_context, namesRef, i)));
}
JSC_JSPropertyNameArrayRelease(m_context, namesRef);
return names;
}
std::unordered_map<std::string, std::string> Object::toJSONMap() const {
std::unordered_map<std::string, std::string> map;
auto namesRef = JSC_JSObjectCopyPropertyNames(m_context, m_obj);
size_t count = JSC_JSPropertyNameArrayGetCount(m_context, namesRef);
for (size_t i = 0; i < count; i++) {
auto key = String::ref(m_context,
JSC_JSPropertyNameArrayGetNameAtIndex(m_context, namesRef, i));
map.emplace(key.str(), getProperty(key).toJSONString());
}
JSC_JSPropertyNameArrayRelease(m_context, namesRef);
return map;
}
/* static */
Object Object::create(JSContextRef ctx) {
JSObjectRef newObj = JSC_JSObjectMake(
ctx,
NULL, // create instance of default object class
NULL); // no private data
return Object(ctx, newObj);
}
} }