xpcom/ds/nsVariant.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* The long avoided variant support for xpcom. */
   8
   9 #ifndef nsVariant_h
  10 #define nsVariant_h
  11
  12 #include "nsIVariant.h"
  13 #include "nsStringFwd.h"
  14 #include "xpt_struct.h"
  15 #include "mozilla/Attributes.h"
  16
  17 class nsCycleCollectionTraversalCallback;
  18
  19 /**
  20  * Map the nsAUTF8String, nsUTF8String classes to the nsACString and
  21  * nsCString classes respectively for now.  These defines need to be removed
  22  * once Jag lands his nsUTF8String implementation.
  23  */
  24 #define nsAUTF8String nsACString
  25 #define nsUTF8String nsCString
  26 #define PromiseFlatUTF8String PromiseFlatCString
  27
  28 /**
  29  * nsDiscriminatedUnion is a type that nsIVariant implementors *may* use
  30  * to hold underlying data. It has no methods. So, its use requires no linkage
  31  * to the xpcom module.
  32  */
  33
  34 struct nsDiscriminatedUnion
  35 {
  36     union {
  37         int8_t         mInt8Value;
  38         int16_t        mInt16Value;
  39         int32_t        mInt32Value;
  40         int64_t        mInt64Value;
  41         uint8_t        mUint8Value;
  42         uint16_t       mUint16Value;
  43         uint32_t       mUint32Value;
  44         uint64_t       mUint64Value;
  45         float          mFloatValue;
  46         double         mDoubleValue;
  47         bool           mBoolValue;
  48         char           mCharValue;
  49         PRUnichar      mWCharValue;
  50         nsIID          mIDValue;
  51         nsAString*     mAStringValue;
  52         nsAUTF8String* mUTF8StringValue;
  53         nsACString*    mCStringValue;
  54         struct {
  55             nsISupports* mInterfaceValue;
  56             nsIID        mInterfaceID;
  57         } iface;
  58         struct {
  59             nsIID        mArrayInterfaceID;
  60             void*        mArrayValue;
  61             uint32_t     mArrayCount;
  62             uint16_t     mArrayType;
  63         } array;
  64         struct {
  65             char*        mStringValue;
  66             uint32_t     mStringLength;
  67         } str;
  68         struct {
  69             PRUnichar*   mWStringValue;
  70             uint32_t     mWStringLength;
  71         } wstr;
  72     } u;
  73     uint16_t       mType;
  74 };
  75
  76 /**
  77  * nsVariant implements the generic variant support. The xpcom module registers
  78  * a factory (see NS_VARIANT_CONTRACTID in nsIVariant.idl) that will create
  79  * these objects. They are created 'empty' and 'writable'.
  80  *
  81  * nsIVariant users won't usually need to see this class.
  82  *
  83  * This class also has static helper methods that nsIVariant *implementors* can
  84  * use to help them do all the 'standard' nsIVariant data conversions.
  85  */
  86
  87 class nsVariant MOZ_FINAL : public nsIWritableVariant
  88 {
  89 public:
  90     NS_DECL_ISUPPORTS
  91     NS_DECL_NSIVARIANT
  92     NS_DECL_NSIWRITABLEVARIANT
  93
  94     nsVariant();
  95
  96     static nsresult Initialize(nsDiscriminatedUnion* data);
  97     static nsresult Cleanup(nsDiscriminatedUnion* data);
  98
  99     static nsresult ConvertToInt8(const nsDiscriminatedUnion& data, uint8_t *_retval);
 100     static nsresult ConvertToInt16(const nsDiscriminatedUnion& data, int16_t *_retval);
 101     static nsresult ConvertToInt32(const nsDiscriminatedUnion& data, int32_t *_retval);
 102     static nsresult ConvertToInt64(const nsDiscriminatedUnion& data, int64_t *_retval);
 103     static nsresult ConvertToUint8(const nsDiscriminatedUnion& data, uint8_t *_retval);
 104     static nsresult ConvertToUint16(const nsDiscriminatedUnion& data, uint16_t *_retval);
 105     static nsresult ConvertToUint32(const nsDiscriminatedUnion& data, uint32_t *_retval);
 106     static nsresult ConvertToUint64(const nsDiscriminatedUnion& data, uint64_t *_retval);
 107     static nsresult ConvertToFloat(const nsDiscriminatedUnion& data, float *_retval);
 108     static nsresult ConvertToDouble(const nsDiscriminatedUnion& data, double *_retval);
 109     static nsresult ConvertToBool(const nsDiscriminatedUnion& data, bool *_retval);
 110     static nsresult ConvertToChar(const nsDiscriminatedUnion& data, char *_retval);
 111     static nsresult ConvertToWChar(const nsDiscriminatedUnion& data, PRUnichar *_retval);
 112     static nsresult ConvertToID(const nsDiscriminatedUnion& data, nsID * _retval);
 113     static nsresult ConvertToAString(const nsDiscriminatedUnion& data, nsAString & _retval);
 114     static nsresult ConvertToAUTF8String(const nsDiscriminatedUnion& data, nsAUTF8String & _retval);
 115     static nsresult ConvertToACString(const nsDiscriminatedUnion& data, nsACString & _retval);
 116     static nsresult ConvertToString(const nsDiscriminatedUnion& data, char **_retval);
 117     static nsresult ConvertToWString(const nsDiscriminatedUnion& data, PRUnichar **_retval);
 118     static nsresult ConvertToISupports(const nsDiscriminatedUnion& data, nsISupports **_retval);
 119     static nsresult ConvertToInterface(const nsDiscriminatedUnion& data, nsIID * *iid, void * *iface);
 120     static nsresult ConvertToArray(const nsDiscriminatedUnion& data, uint16_t *type, nsIID* iid, uint32_t *count, void * *ptr);
 121     static nsresult ConvertToStringWithSize(const nsDiscriminatedUnion& data, uint32_t *size, char **str);
 122     static nsresult ConvertToWStringWithSize(const nsDiscriminatedUnion& data, uint32_t *size, PRUnichar **str);
 123
 124     static nsresult SetFromVariant(nsDiscriminatedUnion* data, nsIVariant* aValue);
 125
 126     static nsresult SetFromInt8(nsDiscriminatedUnion* data, uint8_t aValue);
 127     static nsresult SetFromInt16(nsDiscriminatedUnion* data, int16_t aValue);
 128     static nsresult SetFromInt32(nsDiscriminatedUnion* data, int32_t aValue);
 129     static nsresult SetFromInt64(nsDiscriminatedUnion* data, int64_t aValue);
 130     static nsresult SetFromUint8(nsDiscriminatedUnion* data, uint8_t aValue);
 131     static nsresult SetFromUint16(nsDiscriminatedUnion* data, uint16_t aValue);
 132     static nsresult SetFromUint32(nsDiscriminatedUnion* data, uint32_t aValue);
 133     static nsresult SetFromUint64(nsDiscriminatedUnion* data, uint64_t aValue);
 134     static nsresult SetFromFloat(nsDiscriminatedUnion* data, float aValue);
 135     static nsresult SetFromDouble(nsDiscriminatedUnion* data, double aValue);
 136     static nsresult SetFromBool(nsDiscriminatedUnion* data, bool aValue);
 137     static nsresult SetFromChar(nsDiscriminatedUnion* data, char aValue);
 138     static nsresult SetFromWChar(nsDiscriminatedUnion* data, PRUnichar aValue);
 139     static nsresult SetFromID(nsDiscriminatedUnion* data, const nsID & aValue);
 140     static nsresult SetFromAString(nsDiscriminatedUnion* data, const nsAString & aValue);
 141     static nsresult SetFromAUTF8String(nsDiscriminatedUnion* data, const nsAUTF8String & aValue);
 142     static nsresult SetFromACString(nsDiscriminatedUnion* data, const nsACString & aValue);
 143     static nsresult SetFromString(nsDiscriminatedUnion* data, const char *aValue);
 144     static nsresult SetFromWString(nsDiscriminatedUnion* data, const PRUnichar *aValue);
 145     static nsresult SetFromISupports(nsDiscriminatedUnion* data, nsISupports *aValue);
 146     static nsresult SetFromInterface(nsDiscriminatedUnion* data, const nsIID& iid, nsISupports *aValue);
 147     static nsresult SetFromArray(nsDiscriminatedUnion* data, uint16_t type, const nsIID* iid, uint32_t count, void * aValue);
 148     static nsresult SetFromStringWithSize(nsDiscriminatedUnion* data, uint32_t size, const char *aValue);
 149     static nsresult SetFromWStringWithSize(nsDiscriminatedUnion* data, uint32_t size, const PRUnichar *aValue);
 150
 151     static nsresult SetToVoid(nsDiscriminatedUnion* data);
 152     static nsresult SetToEmpty(nsDiscriminatedUnion* data);
 153     static nsresult SetToEmptyArray(nsDiscriminatedUnion* data);
 154
 155     static void Traverse(const nsDiscriminatedUnion& data,
 156                          nsCycleCollectionTraversalCallback &cb);
 157
 158 private:
 159     ~nsVariant();
 160
 161 protected:
 162     nsDiscriminatedUnion mData;
 163     bool                 mWritable;
 164 };
 165
 166 /**
 167  * Users of nsIVariant should be using the contractID and not this CID.
 168  *  - see NS_VARIANT_CONTRACTID in nsIVariant.idl.
 169  */
 170
 171 #define NS_VARIANT_CID \
 172 { /* 0D6EA1D0-879C-11d5-90EF-0010A4E73D9A */ \
 173     0xd6ea1d0,                               \
 174     0x879c,                                  \
 175     0x11d5,                                  \
 176     {0x90, 0xef, 0x0, 0x10, 0xa4, 0xe7, 0x3d, 0x9a}}
 177
 178 #define NS_VARIANT_CLASSNAME "Variant"
 179
 180 #endif // nsVariant_h