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