122 lines
3.6 KiB
C++
122 lines
3.6 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* vim: set ts=8 sts=2 et sw=2 tw=80:
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* Shadow definition of |JSString| innards. Don't use this directly! */
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#ifndef js_shadow_String_h
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#define js_shadow_String_h
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#include <stdint.h> // uint32_t, uintptr_t
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#include "jstypes.h" // JS_PUBLIC_API, js::Bit, js::BitMask, JS_BITS_PER_WORD
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#include "js/TypeDecls.h" // JS::Latin1Char
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class JS_PUBLIC_API JSAtom;
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struct JSExternalStringCallbacks;
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class JSLinearString;
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class JS_PUBLIC_API JSString;
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namespace js {
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namespace gc {
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struct Cell;
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} // namespace gc
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} // namespace js
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namespace JS {
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namespace shadow {
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struct String {
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static constexpr uint32_t ATOM_BIT = js::Bit(3);
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static constexpr uint32_t LINEAR_BIT = js::Bit(4);
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static constexpr uint32_t INLINE_CHARS_BIT = js::Bit(6);
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static constexpr uint32_t LATIN1_CHARS_BIT = js::Bit(10);
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static constexpr uint32_t HAS_STRING_BUFFER_BIT = js::Bit(12);
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static constexpr uint32_t EXTERNAL_FLAGS = LINEAR_BIT | js::Bit(8);
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static constexpr uint32_t TYPE_FLAGS_MASK = js::BitMask(10) - js::BitMask(3);
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static constexpr uint32_t PERMANENT_ATOM_MASK = ATOM_BIT | js::Bit(8);
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uintptr_t flags_;
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#if JS_BITS_PER_WORD == 32
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uint32_t length_;
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#endif
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union {
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const JS::Latin1Char* nonInlineCharsLatin1;
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const char16_t* nonInlineCharsTwoByte;
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JS::Latin1Char inlineStorageLatin1[1];
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char16_t inlineStorageTwoByte[1];
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};
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const JSExternalStringCallbacks* externalCallbacks;
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uint32_t flags() const { return static_cast<uint32_t>(flags_); }
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uint32_t length() const {
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#if JS_BITS_PER_WORD == 32
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return length_;
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#else
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return static_cast<uint32_t>(flags_ >> 32);
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#endif
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}
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static bool isPermanentAtom(const js::gc::Cell* cell) {
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uint32_t flags = reinterpret_cast<const String*>(cell)->flags();
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return (flags & PERMANENT_ATOM_MASK) == PERMANENT_ATOM_MASK;
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}
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bool isLinear() const { return flags() & LINEAR_BIT; }
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bool hasLatin1Chars() const { return flags() & LATIN1_CHARS_BIT; }
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bool hasStringBuffer() const { return flags() & HAS_STRING_BUFFER_BIT; }
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// For hot code, prefer other type queries.
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bool isExternal() const {
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return (flags() & TYPE_FLAGS_MASK) == EXTERNAL_FLAGS;
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}
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const JS::Latin1Char* latin1LinearChars() const {
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MOZ_ASSERT(isLinear());
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MOZ_ASSERT(hasLatin1Chars());
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return (flags() & String::INLINE_CHARS_BIT) ? inlineStorageLatin1
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: nonInlineCharsLatin1;
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}
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const char16_t* twoByteLinearChars() const {
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MOZ_ASSERT(isLinear());
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MOZ_ASSERT(!hasLatin1Chars());
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return (flags() & String::INLINE_CHARS_BIT) ? inlineStorageTwoByte
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: nonInlineCharsTwoByte;
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}
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};
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inline const String* AsShadowString(const JSString* str) {
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return reinterpret_cast<const String*>(str);
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}
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inline String* AsShadowString(JSString* str) {
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return reinterpret_cast<String*>(str);
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}
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inline const String* AsShadowString(const JSLinearString* str) {
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return reinterpret_cast<const String*>(str);
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}
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inline String* AsShadowString(JSLinearString* str) {
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return reinterpret_cast<String*>(str);
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}
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inline const String* AsShadowString(const JSAtom* str) {
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return reinterpret_cast<const String*>(str);
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}
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inline String* AsShadowString(JSAtom* str) {
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return reinterpret_cast<String*>(str);
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}
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} // namespace shadow
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} // namespace JS
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#endif // js_shadow_String_h
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