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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 */
#ifndef nsVariant_h
#define nsVariant_h
#include "nsIVariant.h"
#include "nsStringFwd.h"
#include "mozilla/Attributes.h"
#include "nsCycleCollectionParticipant.h"
* Map the nsAUTF8String, nsUTF8String classes to the nsACString and
* nsCString classes respectively for now. These defines need to be removed
* once Jag lands his nsUTF8String implementation.
#define nsAUTF8String nsACString
#define nsUTF8String nsCString
#define PromiseFlatUTF8String PromiseFlatCString
* nsDiscriminatedUnion is a class that nsIVariant implementors can use
* to hold the underlying data.
class nsDiscriminatedUnion {
nsDiscriminatedUnion() : mType(nsIDataType::VTYPE_EMPTY) {
u.mInt8Value = '\0';
nsDiscriminatedUnion(const nsDiscriminatedUnion&) = delete;
nsDiscriminatedUnion(nsDiscriminatedUnion&&) = delete;
~nsDiscriminatedUnion() { Cleanup(); }
nsDiscriminatedUnion& operator=(const nsDiscriminatedUnion&) = delete;
nsDiscriminatedUnion& operator=(nsDiscriminatedUnion&&) = delete;
void Cleanup();
uint16_t GetType() const { return mType; }
[[nodiscard]] nsresult ConvertToInt8(uint8_t* aResult) const;
[[nodiscard]] nsresult ConvertToInt16(int16_t* aResult) const;
[[nodiscard]] nsresult ConvertToInt32(int32_t* aResult) const;
[[nodiscard]] nsresult ConvertToInt64(int64_t* aResult) const;
[[nodiscard]] nsresult ConvertToUint8(uint8_t* aResult) const;
[[nodiscard]] nsresult ConvertToUint16(uint16_t* aResult) const;
[[nodiscard]] nsresult ConvertToUint32(uint32_t* aResult) const;
[[nodiscard]] nsresult ConvertToUint64(uint64_t* aResult) const;
[[nodiscard]] nsresult ConvertToFloat(float* aResult) const;
[[nodiscard]] nsresult ConvertToDouble(double* aResult) const;
[[nodiscard]] nsresult ConvertToBool(bool* aResult) const;
[[nodiscard]] nsresult ConvertToChar(char* aResult) const;
[[nodiscard]] nsresult ConvertToWChar(char16_t* aResult) const;
[[nodiscard]] nsresult ConvertToID(nsID* aResult) const;
[[nodiscard]] nsresult ConvertToAString(nsAString& aResult) const;
[[nodiscard]] nsresult ConvertToAUTF8String(nsAUTF8String& aResult) const;
[[nodiscard]] nsresult ConvertToACString(nsACString& aResult) const;
[[nodiscard]] nsresult ConvertToString(char** aResult) const;
[[nodiscard]] nsresult ConvertToWString(char16_t** aResult) const;
[[nodiscard]] nsresult ConvertToStringWithSize(uint32_t* aSize,
char** aStr) const;
[[nodiscard]] nsresult ConvertToWStringWithSize(uint32_t* aSize,
char16_t** aStr) const;
[[nodiscard]] nsresult ConvertToISupports(nsISupports** aResult) const;
[[nodiscard]] nsresult ConvertToInterface(nsIID** aIID,
void** aInterface) const;
[[nodiscard]] nsresult ConvertToArray(uint16_t* aType, nsIID* aIID,
uint32_t* aCount, void** aPtr) const;
[[nodiscard]] nsresult SetFromVariant(nsIVariant* aValue);
void SetFromInt8(uint8_t aValue);
void SetFromInt16(int16_t aValue);
void SetFromInt32(int32_t aValue);
void SetFromInt64(int64_t aValue);
void SetFromUint8(uint8_t aValue);
void SetFromUint16(uint16_t aValue);
void SetFromUint32(uint32_t aValue);
void SetFromUint64(uint64_t aValue);
void SetFromFloat(float aValue);
void SetFromDouble(double aValue);
void SetFromBool(bool aValue);
void SetFromChar(char aValue);
void SetFromWChar(char16_t aValue);
void SetFromID(const nsID& aValue);
void SetFromAString(const nsAString& aValue);
void SetFromAUTF8String(const nsAUTF8String& aValue);
void SetFromACString(const nsACString& aValue);
[[nodiscard]] nsresult SetFromString(const char* aValue);
[[nodiscard]] nsresult SetFromWString(const char16_t* aValue);
void SetFromISupports(nsISupports* aValue);
void SetFromInterface(const nsIID& aIID, nsISupports* aValue);
[[nodiscard]] nsresult SetFromArray(uint16_t aType, const nsIID* aIID,
uint32_t aCount, void* aValue);
[[nodiscard]] nsresult SetFromStringWithSize(uint32_t aSize,
const char* aValue);
[[nodiscard]] nsresult SetFromWStringWithSize(uint32_t aSize,
const char16_t* aValue);
// Like SetFromWStringWithSize, but leaves the string uninitialized. It does
// does write the null-terminator.
void AllocateWStringWithSize(uint32_t aSize);
void SetToVoid();
void SetToEmpty();
void SetToEmptyArray();
void Traverse(nsCycleCollectionTraversalCallback& aCb) const;
[[nodiscard]] nsresult ToManageableNumber(
nsDiscriminatedUnion* aOutData) const;
void FreeArray();
[[nodiscard]] bool String2ID(nsID* aPid) const;
[[nodiscard]] nsresult ToString(nsACString& aOutString) const;
union {
int8_t mInt8Value;
int16_t mInt16Value;
int32_t mInt32Value;
int64_t mInt64Value;
uint8_t mUint8Value;
uint16_t mUint16Value;
uint32_t mUint32Value;
uint64_t mUint64Value;
float mFloatValue;
double mDoubleValue;
bool mBoolValue;
char mCharValue;
char16_t mWCharValue;
nsIID mIDValue;
nsAString* mAStringValue;
nsAUTF8String* mUTF8StringValue;
nsACString* mCStringValue;
struct {
// This is an owning reference that cannot be an nsCOMPtr because
// nsDiscriminatedUnion needs to be POD. AddRef/Release are manually
// called on this.
nsISupports* MOZ_OWNING_REF mInterfaceValue;
nsIID mInterfaceID;
} iface;
struct {
nsIID mArrayInterfaceID;
void* mArrayValue;
uint32_t mArrayCount;
uint16_t mArrayType;
} array;
struct {
char* mStringValue;
uint32_t mStringLength;
} str;
struct {
char16_t* mWStringValue;
uint32_t mWStringLength;
} wstr;
} u;
uint16_t mType;
* nsVariant implements the generic variant support. The xpcom module registers
* a factory (see NS_VARIANT_CONTRACTID in nsIVariant.idl) that will create
* these objects. They are created 'empty' and 'writable'.
* nsIVariant users won't usually need to see this class.
class nsVariantBase : public nsIWritableVariant {
~nsVariantBase() = default;
nsDiscriminatedUnion mData;
bool mWritable;
class nsVariant final : public nsVariantBase {
nsVariant() = default;
~nsVariant() = default;
class nsVariantCC final : public nsVariantBase {
nsVariantCC() = default;
~nsVariantCC() = default;
* Users of nsIVariant should be using the contractID and not this CID.
* - see NS_VARIANT_CONTRACTID in nsIVariant.idl.
#define NS_VARIANT_CID \
{ /* 0D6EA1D0-879C-11d5-90EF-0010A4E73D9A */ \
0xd6ea1d0, 0x879c, 0x11d5, { \
0x90, 0xef, 0x0, 0x10, 0xa4, 0xe7, 0x3d, 0x9a \
} \
#endif // nsVariant_h