nsVariant.h - mozsearch

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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/. */

#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 {

 public:

  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;

 private:

  [[nodiscard]] nsresult ToManageableNumber(

      nsDiscriminatedUnion* aOutData) const;

  void FreeArray();

  [[nodiscard]] bool String2ID(nsID* aPid) const;

  [[nodiscard]] nsresult ToString(nsACString& aOutString) const;

 public:

  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 {

 public:

  NS_DECL_NSIVARIANT

  NS_DECL_NSIWRITABLEVARIANT

  nsVariantBase();

 protected:

  ~nsVariantBase() = default;

  nsDiscriminatedUnion mData;

  bool mWritable;

};

class nsVariant final : public nsVariantBase {

 public:

  NS_DECL_ISUPPORTS

  nsVariant() = default;

 private:

  ~nsVariant() = default;

};

class nsVariantCC final : public nsVariantBase {

 public:

  NS_DECL_CYCLE_COLLECTING_ISUPPORTS

  NS_DECL_CYCLE_COLLECTION_CLASS(nsVariantCC)

  nsVariantCC() = default;

 private:

  ~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