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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
/* Shadow definition of |JSString| innards. Don't use this directly! */
#ifndef js_shadow_String_h
#define js_shadow_String_h
#include <stdint.h> // uint32_t, uintptr_t
#include "jstypes.h" // JS_PUBLIC_API, js::Bit, js::BitMask, JS_BITS_PER_WORD
#include "js/TypeDecls.h" // JS::Latin1Char
class JS_PUBLIC_API JSAtom;
struct JSExternalStringCallbacks;
class JSLinearString;
class JS_PUBLIC_API JSString;
namespace js {
namespace gc {
struct Cell;
} // namespace gc
} // namespace js
namespace JS {
namespace shadow {
struct String {
static constexpr uint32_t ATOM_BIT = js::Bit(3);
static constexpr uint32_t LINEAR_BIT = js::Bit(4);
static constexpr uint32_t INLINE_CHARS_BIT = js::Bit(6);
static constexpr uint32_t LATIN1_CHARS_BIT = js::Bit(10);
static constexpr uint32_t EXTERNAL_FLAGS = LINEAR_BIT | js::Bit(8);
static constexpr uint32_t TYPE_FLAGS_MASK = js::BitMask(10) - js::BitMask(3);
static constexpr uint32_t PERMANENT_ATOM_MASK = ATOM_BIT | js::Bit(8);
uintptr_t flags_;
#if JS_BITS_PER_WORD == 32
uint32_t length_;
#endif
union {
const JS::Latin1Char* nonInlineCharsLatin1;
const char16_t* nonInlineCharsTwoByte;
JS::Latin1Char inlineStorageLatin1[1];
char16_t inlineStorageTwoByte[1];
};
const JSExternalStringCallbacks* externalCallbacks;
uint32_t flags() const { return static_cast<uint32_t>(flags_); }
uint32_t length() const {
#if JS_BITS_PER_WORD == 32
return length_;
#else
return static_cast<uint32_t>(flags_ >> 32);
#endif
}
static bool isPermanentAtom(const js::gc::Cell* cell) {
uint32_t flags = reinterpret_cast<const String*>(cell)->flags();
return (flags & PERMANENT_ATOM_MASK) == PERMANENT_ATOM_MASK;
}
bool isLinear() const { return flags() & LINEAR_BIT; }
bool hasLatin1Chars() const { return flags() & LATIN1_CHARS_BIT; }
// For hot code, prefer other type queries.
bool isExternal() const {
return (flags() & TYPE_FLAGS_MASK) == EXTERNAL_FLAGS;
}
const JS::Latin1Char* latin1LinearChars() const {
MOZ_ASSERT(isLinear());
MOZ_ASSERT(hasLatin1Chars());
return (flags() & String::INLINE_CHARS_BIT) ? inlineStorageLatin1
: nonInlineCharsLatin1;
}
const char16_t* twoByteLinearChars() const {
MOZ_ASSERT(isLinear());
MOZ_ASSERT(!hasLatin1Chars());
return (flags() & String::INLINE_CHARS_BIT) ? inlineStorageTwoByte
: nonInlineCharsTwoByte;
}
};
inline const String* AsShadowString(const JSString* str) {
return reinterpret_cast<const String*>(str);
}
inline String* AsShadowString(JSString* str) {
return reinterpret_cast<String*>(str);
}
inline const String* AsShadowString(const JSLinearString* str) {
return reinterpret_cast<const String*>(str);
}
inline String* AsShadowString(JSLinearString* str) {
return reinterpret_cast<String*>(str);
}
inline const String* AsShadowString(const JSAtom* str) {
return reinterpret_cast<const String*>(str);
}
inline String* AsShadowString(JSAtom* str) {
return reinterpret_cast<String*>(str);
}
} // namespace shadow
} // namespace JS
#endif // js_shadow_String_h