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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/** GC-safe representations of consecutive JS::Value in memory. */
#ifndef js_ValueArray_h
#define js_ValueArray_h
#include "mozilla/Assertions.h" // MOZ_ASSERT
#include "mozilla/Attributes.h" // MOZ_IMPLICIT, MOZ_RAII
#include <stdint.h> // size_t
#include "js/CallArgs.h" // JS::CallArgs
#include "js/GCVector.h" // JS::RootedVector
#include "js/RootingAPI.h" // JS::AutoGCRooter, JS::{,Mutable}Handle
#include "js/Value.h" // JS::Value
namespace js {
JS_PUBLIC_API void TraceValueArray(JSTracer* trc, size_t length,
JS::Value* elements);
} // namespace js
namespace JS {
/* A fixed-size array of values, for use inside Rooted<>. */
template <size_t N>
struct ValueArray {
Value elements[N];
void trace(JSTracer* trc) { js::TraceValueArray(trc, N, elements); }
};
/** RootedValueArray roots an internal fixed-size array of Values. */
template <size_t N>
using RootedValueArray = Rooted<ValueArray<N>>;
/**
* A generic handle to an array of rooted values.
*
* The rooted array refernced can take several forms, therfore this is not the
* same as Handle<js::ValueArray>.
*/
class HandleValueArray {
const size_t length_;
const Value* const elements_;
HandleValueArray(size_t len, const Value* elements)
: length_(len), elements_(elements) {}
public:
explicit HandleValueArray(Handle<Value> value)
: length_(1), elements_(value.address()) {}
MOZ_IMPLICIT HandleValueArray(const RootedVector<Value>& values)
: length_(values.length()), elements_(values.begin()) {}
template <size_t N>
MOZ_IMPLICIT HandleValueArray(const RootedValueArray<N>& values)
: length_(N), elements_(values.begin()) {}
/** CallArgs must already be rooted somewhere up the stack. */
MOZ_IMPLICIT HandleValueArray(const JS::CallArgs& args)
: length_(args.length()), elements_(args.array()) {}
/** Use with care! Only call this if the data is guaranteed to be marked. */
static HandleValueArray fromMarkedLocation(size_t len,
const Value* elements) {
return HandleValueArray(len, elements);
}
static HandleValueArray subarray(const HandleValueArray& values,
size_t startIndex, size_t len) {
MOZ_ASSERT(startIndex + len <= values.length());
return HandleValueArray(len, values.begin() + startIndex);
}
static HandleValueArray empty() { return HandleValueArray(0, nullptr); }
size_t length() const { return length_; }
const Value* begin() const { return elements_; }
Handle<Value> operator[](size_t i) const {
MOZ_ASSERT(i < length_);
return Handle<Value>::fromMarkedLocation(&elements_[i]);
}
};
} // namespace JS
namespace js {
template <size_t N, typename Container>
class WrappedPtrOperations<JS::ValueArray<N>, Container> {
const JS::ValueArray<N>& array() const {
return static_cast<const Container*>(this)->get();
}
public:
size_t length() const { return N; }
const JS::Value* begin() const { return array().elements; }
JS::HandleValue operator[](size_t i) const {
MOZ_ASSERT(i < N);
return JS::HandleValue::fromMarkedLocation(&array().elements[i]);
}
};
template <size_t N, typename Container>
class MutableWrappedPtrOperations<JS::ValueArray<N>, Container>
: public WrappedPtrOperations<JS::ValueArray<N>, Container> {
using Base = WrappedPtrOperations<JS::ValueArray<N>, Container>;
JS::ValueArray<N>& array() { return static_cast<Container*>(this)->get(); }
public:
using Base::begin;
JS::Value* begin() { return array().elements; }
using Base::operator[];
JS::MutableHandleValue operator[](size_t i) {
MOZ_ASSERT(i < N);
return JS::MutableHandleValue::fromMarkedLocation(&array().elements[i]);
}
};
} // namespace js
#endif // js_ValueArray_h
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