C++ mozilla::PodCopy方法代码示例

JSString *
js::ConcatStrings(ThreadSafeContext *cx,
                  typename MaybeRooted<JSString*, allowGC>::HandleType left,
                  typename MaybeRooted<JSString*, allowGC>::HandleType right)
{
    JS_ASSERT_IF(!left->isAtom(), cx->isInsideCurrentZone(left));
    JS_ASSERT_IF(!right->isAtom(), cx->isInsideCurrentZone(right));

    size_t leftLen = left->length();
    if (leftLen == 0)
        return right;

    size_t rightLen = right->length();
    if (rightLen == 0)
        return left;

    size_t wholeLength = leftLen + rightLen;
    if (!JSString::validateLength(cx, wholeLength))
        return nullptr;

    bool isLatin1 = left->hasLatin1Chars() && right->hasLatin1Chars();
    bool canUseFatInline = isLatin1
                           ? JSFatInlineString::latin1LengthFits(wholeLength)
                           : JSFatInlineString::twoByteLengthFits(wholeLength);
    if (canUseFatInline && cx->isJSContext()) {
        JSFatInlineString *str = js_NewGCFatInlineString<allowGC>(cx);
        if (!str)
            return nullptr;

        AutoCheckCannotGC nogc;
        ScopedThreadSafeStringInspector leftInspector(left);
        ScopedThreadSafeStringInspector rightInspector(right);
        if (!leftInspector.ensureChars(cx, nogc) || !rightInspector.ensureChars(cx, nogc))
            return nullptr;

        if (isLatin1) {
            Latin1Char *buf = str->initLatin1(wholeLength);
            PodCopy(buf, leftInspector.latin1Chars(), leftLen);
            PodCopy(buf + leftLen, rightInspector.latin1Chars(), rightLen);
            buf[wholeLength] = 0;
        } else {
            jschar *buf = str->initTwoByte(wholeLength);
            if (leftInspector.hasTwoByteChars())
                PodCopy(buf, leftInspector.twoByteChars(), leftLen);
            else
                CopyAndInflateChars(buf, leftInspector.latin1Chars(), leftLen);
            if (rightInspector.hasTwoByteChars())
                PodCopy(buf + leftLen, rightInspector.twoByteChars(), rightLen);
            else
                CopyAndInflateChars(buf + leftLen, rightInspector.latin1Chars(), rightLen);
            buf[wholeLength] = 0;
        }

        return str;
    }

    return JSRope::new_<allowGC>(cx, left, right, wholeLength);
}

bool
StackFrame::copyRawFrameSlots(AutoValueVector *vec)
{
    if (!vec->resize(numFormalArgs() + script()->nfixed()))
        return false;
    PodCopy(vec->begin(), argv(), numFormalArgs());
    PodCopy(vec->begin() + numFormalArgs(), slots(), script()->nfixed());
    return true;
}

JSFlatString *
JSDependentString::undependInternal(ExclusiveContext *cx)
{
    /*
     * We destroy the base() pointer in undepend, so we need a pre-barrier. We
     * don't need a post-barrier because there aren't any outgoing pointers
     * afterwards.
     */
    JSString::writeBarrierPre(base());

    size_t n = length();
    CharT *s = cx->pod_malloc<CharT>(n + 1);
    if (!s)
        return nullptr;

    AutoCheckCannotGC nogc;
    PodCopy(s, nonInlineChars<CharT>(nogc), n);
    s[n] = '\0';
    setNonInlineChars<CharT>(s);

    /*
     * Transform *this into an undepended string so 'base' will remain rooted
     * for the benefit of any other dependent string that depends on *this.
     */
    if (IsSame<CharT, Latin1Char>::value)
        d.u1.flags = UNDEPENDED_FLAGS | LATIN1_CHARS_BIT;
    else
        d.u1.flags = UNDEPENDED_FLAGS;

    return &this->asFlat();
}

NS_IMETHODIMP
nsBinaryInputStream::ReadArrayBuffer(uint32_t aLength,
                                     JS::Handle<JS::Value> aBuffer,
                                     JSContext* aCx, uint32_t* aReadLength)
{
  if (!aBuffer.isObject()) {
    return NS_ERROR_FAILURE;
  }
  JS::RootedObject buffer(aCx, &aBuffer.toObject());
  if (!JS_IsArrayBufferObject(buffer)) {
    return NS_ERROR_FAILURE;
  }

  uint32_t bufferLength = JS_GetArrayBufferByteLength(buffer);
  if (bufferLength < aLength) {
    return NS_ERROR_FAILURE;
  }

  uint32_t bufSize = std::min<uint32_t>(aLength, 4096);
  UniquePtr<char[]> buf = MakeUnique<char[]>(bufSize);

  uint32_t pos = 0;
  *aReadLength = 0;
  do {
    // Read data into temporary buffer.
    uint32_t bytesRead;
    uint32_t amount = std::min(aLength - pos, bufSize);
    nsresult rv = Read(buf.get(), amount, &bytesRead);
    if (NS_WARN_IF(NS_FAILED(rv))) {
      return rv;
    }
    MOZ_ASSERT(bytesRead <= amount);

    if (bytesRead == 0) {
      break;
    }

    // Copy data into actual buffer.

    JS::AutoCheckCannotGC nogc;
    bool isShared;
    if (bufferLength != JS_GetArrayBufferByteLength(buffer)) {
      return NS_ERROR_FAILURE;
    }

    char* data = reinterpret_cast<char*>(JS_GetArrayBufferData(buffer, &isShared, nogc));
    MOZ_ASSERT(!isShared);      // Implied by JS_GetArrayBufferData()
    if (!data) {
      return NS_ERROR_FAILURE;
    }

    *aReadLength += bytesRead;
    PodCopy(data + pos, buf.get(), bytesRead);

    pos += bytesRead;
  } while (pos < aLength);

  return NS_OK;
}

void
CopyChars(jschar *dest, const JSLinearString &str)
{
    AutoCheckCannotGC nogc;
    if (str.hasTwoByteChars())
        PodCopy(dest, str.twoByteChars(nogc), str.length());
    else
        CopyAndInflateChars(dest, str.latin1Chars(nogc), str.length());
}

bool
MatchPairs::initArrayFrom(MatchPairs& copyFrom)
{
    MOZ_ASSERT(copyFrom.pairCount() > 0);

    if (!allocOrExpandArray(copyFrom.pairCount()))
        return false;

    PodCopy(pairs_, copyFrom.pairs_, pairCount_);

    return true;
}

bool
CacheableChars::clone(JSContext* cx, CacheableChars* out) const
{
    uint32_t length = NullableStringLength(get());

    UniqueChars chars(cx->pod_calloc<char>(length + 1));
    if (!chars)
        return false;

    PodCopy(chars.get(), get(), length);

    *out = Move(chars);
    return true;
}

static bool
DecodeFuncBody(JSContext* cx, Decoder& d, ModuleGenerator& mg, FunctionGenerator& fg,
               uint32_t funcIndex)
{
    const uint8_t* bodyBegin = d.currentPosition();

    FunctionDecoder f(cx, d, mg, fg, funcIndex);
    if (!DecodeExpr(f, f.ret()))
        return false;

    const uint8_t* bodyEnd = d.currentPosition();
    uintptr_t bodyLength = bodyEnd - bodyBegin;
    if (!fg.bytecode().resize(bodyLength))
        return false;

    PodCopy(fg.bytecode().begin(), bodyBegin, bodyLength);
    return true;
}

JSFlatString*
JSDependentString::undependInternal(ExclusiveContext* cx)
{
    size_t n = length();
    CharT* s = cx->pod_malloc<CharT>(n + 1);
    if (!s)
        return nullptr;

    AutoCheckCannotGC nogc;
    PodCopy(s, nonInlineChars<CharT>(nogc), n);
    s[n] = '\0';
    setNonInlineChars<CharT>(s);

    /*
     * Transform *this into an undepended string so 'base' will remain rooted
     * for the benefit of any other dependent string that depends on *this.
     */
    if (IsSame<CharT, Latin1Char>::value)
        d.u1.flags = UNDEPENDED_FLAGS | LATIN1_CHARS_BIT;
    else
        d.u1.flags = UNDEPENDED_FLAGS;

    return &this->asFlat();
}

//.........这里部分代码省略.........
            // This hook has the full control over what gets enumerated.
            AutoIdVector properties(cx);
            if (!enumerate(cx, pobj, properties))
                 return false;

            for (size_t n = 0; n < properties.length(); n++) {
                if (!Enumerate(cx, pobj, properties[n], true, flags, ht, props))
                    return false;
            }

            if (pobj->isNative()) {
                if (!EnumerateNativeProperties(cx, pobj.as<NativeObject>(), flags, ht, props))
                    return false;
            }
        } else if (pobj->isNative()) {
            // Give the object a chance to resolve all lazy properties
            if (JSEnumerateOp enumerate = pobj->getClass()->enumerate) {
                if (!enumerate(cx, pobj.as<NativeObject>()))
                    return false;
            }
            if (!EnumerateNativeProperties(cx, pobj.as<NativeObject>(), flags, ht, props))
                return false;
        } else if (pobj->is<ProxyObject>()) {
            AutoIdVector proxyProps(cx);
            if (flags & JSITER_HIDDEN || flags & JSITER_SYMBOLS) {
                // This gets all property keys, both strings and
                // symbols.  The call to Enumerate in the loop below
                // will filter out unwanted keys, per the flags.
                if (!Proxy::ownPropertyKeys(cx, pobj, proxyProps))
                    return false;

                Rooted<PropertyDescriptor> desc(cx);
                for (size_t n = 0, len = proxyProps.length(); n < len; n++) {
                    bool enumerable = false;

                    // We need to filter, if the caller just wants enumerable
                    // symbols.
                    if (!(flags & JSITER_HIDDEN)) {
                        if (!Proxy::getOwnPropertyDescriptor(cx, pobj, proxyProps[n], &desc))
                            return false;
                        enumerable = desc.enumerable();
                    }

                    if (!Enumerate(cx, pobj, proxyProps[n], enumerable, flags, ht, props))
                        return false;
                }
            } else {
                // Returns enumerable property names (no symbols).
                if (!Proxy::getOwnEnumerablePropertyKeys(cx, pobj, proxyProps))
                    return false;

                for (size_t n = 0, len = proxyProps.length(); n < len; n++) {
                    if (!Enumerate(cx, pobj, proxyProps[n], true, flags, ht, props))
                        return false;
                }
            }
        } else {
            MOZ_CRASH("non-native objects must have an enumerate op");
        }

        if (flags & JSITER_OWNONLY)
            break;

        if (!GetPrototype(cx, pobj, &pobj))
            return false;

    } while (pobj != nullptr);

#ifdef JS_MORE_DETERMINISTIC

    /*
     * In some cases the enumeration order for an object depends on the
     * execution mode (interpreter vs. JIT), especially for native objects
     * with a class enumerate hook (where resolving a property changes the
     * resulting enumeration order). These aren't really bugs, but the
     * differences can change the generated output and confuse correctness
     * fuzzers, so we sort the ids if such a fuzzer is running.
     *
     * We don't do this in the general case because (a) doing so is slow,
     * and (b) it also breaks the web, which expects enumeration order to
     * follow the order in which properties are added, in certain cases.
     * Since ECMA does not specify an enumeration order for objects, both
     * behaviors are technically correct to do.
     */

    jsid* ids = props->begin();
    size_t n = props->length();

    AutoIdVector tmp(cx);
    if (!tmp.resize(n))
        return false;
    PodCopy(tmp.begin(), ids, n);

    if (!MergeSort(ids, n, tmp.begin(), SortComparatorIds(cx)))
        return false;

#endif /* JS_MORE_DETERMINISTIC */

    return true;
}

JSString*
js::ConcatStrings(ExclusiveContext* cx,
                  typename MaybeRooted<JSString*, allowGC>::HandleType left,
                  typename MaybeRooted<JSString*, allowGC>::HandleType right)
{
    MOZ_ASSERT_IF(!left->isAtom(), cx->isInsideCurrentZone(left));
    MOZ_ASSERT_IF(!right->isAtom(), cx->isInsideCurrentZone(right));

    size_t leftLen = left->length();
    if (leftLen == 0)
        return right;

    size_t rightLen = right->length();
    if (rightLen == 0)
        return left;

    size_t wholeLength = leftLen + rightLen;
    if (!JSString::validateLength(cx, wholeLength))
        return nullptr;

    bool isLatin1 = left->hasLatin1Chars() && right->hasLatin1Chars();
    bool canUseInline = isLatin1
                        ? JSInlineString::lengthFits<Latin1Char>(wholeLength)
                        : JSInlineString::lengthFits<char16_t>(wholeLength);
    if (canUseInline && cx->isJSContext()) {
        Latin1Char* latin1Buf = nullptr;  // initialize to silence GCC warning
        char16_t* twoByteBuf = nullptr;  // initialize to silence GCC warning
        JSInlineString* str = isLatin1
            ? AllocateInlineString<allowGC>(cx, wholeLength, &latin1Buf)
            : AllocateInlineString<allowGC>(cx, wholeLength, &twoByteBuf);
        if (!str)
            return nullptr;

        AutoCheckCannotGC nogc;
        JSLinearString* leftLinear = left->ensureLinear(cx);
        if (!leftLinear)
            return nullptr;
        JSLinearString* rightLinear = right->ensureLinear(cx);
        if (!rightLinear)
            return nullptr;

        if (isLatin1) {
            PodCopy(latin1Buf, leftLinear->latin1Chars(nogc), leftLen);
            PodCopy(latin1Buf + leftLen, rightLinear->latin1Chars(nogc), rightLen);
            latin1Buf[wholeLength] = 0;
        } else {
            if (leftLinear->hasTwoByteChars())
                PodCopy(twoByteBuf, leftLinear->twoByteChars(nogc), leftLen);
            else
                CopyAndInflateChars(twoByteBuf, leftLinear->latin1Chars(nogc), leftLen);
            if (rightLinear->hasTwoByteChars())
                PodCopy(twoByteBuf + leftLen, rightLinear->twoByteChars(nogc), rightLen);
            else
                CopyAndInflateChars(twoByteBuf + leftLen, rightLinear->latin1Chars(nogc), rightLen);
            twoByteBuf[wholeLength] = 0;
        }

        return str;
    }

    return JSRope::new_<allowGC>(cx, left, right, wholeLength);
}

static bool
EnumerateNativeProperties(JSContext* cx, HandleNativeObject pobj, unsigned flags, Maybe<IdSet>& ht,
                          AutoIdVector* props, Handle<UnboxedPlainObject*> unboxed = nullptr)
{
    bool enumerateSymbols;
    if (flags & JSITER_SYMBOLSONLY) {
        enumerateSymbols = true;
    } else {
        /* Collect any dense elements from this object. */
        size_t firstElemIndex = props->length();
        size_t initlen = pobj->getDenseInitializedLength();
        const Value* vp = pobj->getDenseElements();
        bool hasHoles = false;
        for (size_t i = 0; i < initlen; ++i, ++vp) {
            if (vp->isMagic(JS_ELEMENTS_HOLE)) {
                hasHoles = true;
            } else {
                /* Dense arrays never get so large that i would not fit into an integer id. */
                if (!Enumerate(cx, pobj, INT_TO_JSID(i), /* enumerable = */ true, flags, ht, props))
                    return false;
            }
        }

        /* Collect any typed array or shared typed array elements from this object. */
        if (pobj->is<TypedArrayObject>()) {
            size_t len = pobj->as<TypedArrayObject>().length();
            for (size_t i = 0; i < len; i++) {
                if (!Enumerate(cx, pobj, INT_TO_JSID(i), /* enumerable = */ true, flags, ht, props))
                    return false;
            }
        }

        // Collect any sparse elements from this object.
        bool isIndexed = pobj->isIndexed();
        if (isIndexed) {
            // If the dense elements didn't have holes, we don't need to include
            // them in the sort.
            if (!hasHoles)
                firstElemIndex = props->length();

            for (Shape::Range<NoGC> r(pobj->lastProperty()); !r.empty(); r.popFront()) {
                Shape& shape = r.front();
                jsid id = shape.propid();
                uint32_t dummy;
                if (IdIsIndex(id, &dummy)) {
                    if (!Enumerate(cx, pobj, id, shape.enumerable(), flags, ht, props))
                        return false;
                }
            }

            MOZ_ASSERT(firstElemIndex <= props->length());

            jsid* ids = props->begin() + firstElemIndex;
            size_t n = props->length() - firstElemIndex;

            AutoIdVector tmp(cx);
            if (!tmp.resize(n))
                return false;
            PodCopy(tmp.begin(), ids, n);

            if (!MergeSort(ids, n, tmp.begin(), SortComparatorIntegerIds))
                return false;
        }

        if (unboxed) {
            // If |unboxed| is set then |pobj| is the expando for an unboxed
            // plain object we are enumerating. Add the unboxed properties
            // themselves here since they are all property names that were
            // given to the object before any of the expando's properties.
            MOZ_ASSERT(pobj->is<UnboxedExpandoObject>());
            if (!EnumerateExtraProperties(cx, unboxed, flags, ht, props))
                return false;
        }

        size_t initialLength = props->length();

        /* Collect all unique property names from this object's shape. */
        bool symbolsFound = false;
        Shape::Range<NoGC> r(pobj->lastProperty());
        for (; !r.empty(); r.popFront()) {
            Shape& shape = r.front();
            jsid id = shape.propid();

            if (JSID_IS_SYMBOL(id)) {
                symbolsFound = true;
                continue;
            }

            uint32_t dummy;
            if (isIndexed && IdIsIndex(id, &dummy))
                continue;

            if (!Enumerate(cx, pobj, id, shape.enumerable(), flags, ht, props))
                return false;
        }
        ::Reverse(props->begin() + initialLength, props->end());

        enumerateSymbols = symbolsFound && (flags & JSITER_SYMBOLS);
    }

//.........这里部分代码省略.........

//.........这里部分代码省略.........
    // The only special case is when the object has a newEnumerate hook: it
    // can return duplicate properties and we have to filter them. This is
    // handled below.
    bool checkForDuplicates = !(flags & JSITER_OWNONLY);

    do {
        if (pobj->getClass()->getNewEnumerate()) {
            if (pobj->is<UnboxedPlainObject>() && pobj->as<UnboxedPlainObject>().maybeExpando()) {
                // Special case unboxed objects with an expando object.
                RootedNativeObject expando(cx, pobj->as<UnboxedPlainObject>().maybeExpando());
                if (!EnumerateNativeProperties(cx, expando, flags, ht, props, checkForDuplicates,
                                               pobj.as<UnboxedPlainObject>()))
                {
                    return false;
                }
            } else {
                // The newEnumerate hook may return duplicates. Whitelist the
                // unboxed object hooks because we know they are well-behaved.
                if (!pobj->is<UnboxedPlainObject>())
                    checkForDuplicates = true;

                if (checkForDuplicates) {
                    if (!EnumerateExtraProperties<true>(cx, pobj, flags, ht, props))
                        return false;
                } else {
                    if (!EnumerateExtraProperties<false>(cx, pobj, flags, ht, props))
                        return false;
                }

                if (pobj->isNative()) {
                    if (!EnumerateNativeProperties(cx, pobj.as<NativeObject>(), flags, ht, props,
                                                   checkForDuplicates))
                    {
                        return false;
                    }
                }
            }
        } else if (pobj->isNative()) {
            // Give the object a chance to resolve all lazy properties
            if (JSEnumerateOp enumerate = pobj->getClass()->getEnumerate()) {
                if (!enumerate(cx, pobj.as<NativeObject>()))
                    return false;
            }
            if (!EnumerateNativeProperties(cx, pobj.as<NativeObject>(), flags, ht, props,
                                           checkForDuplicates))
            {
                return false;
            }
        } else if (pobj->is<ProxyObject>()) {
            if (checkForDuplicates) {
                if (!EnumerateProxyProperties<true>(cx, pobj, flags, ht, props))
                    return false;
            } else {
                if (!EnumerateProxyProperties<false>(cx, pobj, flags, ht, props))
                    return false;
            }
        } else {
            MOZ_CRASH("non-native objects must have an enumerate op");
        }

        if (flags & JSITER_OWNONLY)
            break;

        if (!GetPrototype(cx, pobj, &pobj))
            return false;

    } while (pobj != nullptr);

#ifdef JS_MORE_DETERMINISTIC

    /*
     * In some cases the enumeration order for an object depends on the
     * execution mode (interpreter vs. JIT), especially for native objects
     * with a class enumerate hook (where resolving a property changes the
     * resulting enumeration order). These aren't really bugs, but the
     * differences can change the generated output and confuse correctness
     * fuzzers, so we sort the ids if such a fuzzer is running.
     *
     * We don't do this in the general case because (a) doing so is slow,
     * and (b) it also breaks the web, which expects enumeration order to
     * follow the order in which properties are added, in certain cases.
     * Since ECMA does not specify an enumeration order for objects, both
     * behaviors are technically correct to do.
     */

    jsid* ids = props->begin();
    size_t n = props->length();

    AutoIdVector tmp(cx);
    if (!tmp.resize(n))
        return false;
    PodCopy(tmp.begin(), ids, n);

    if (!MergeSort(ids, n, tmp.begin(), SortComparatorIds(cx)))
        return false;

#endif /* JS_MORE_DETERMINISTIC */

    return true;
}