The Tor Browser: storage/src/Variant.h@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-

     2  * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :

     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/. */

     7 #ifndef mozilla_storage_Variant_h__

     8 #define mozilla_storage_Variant_h__

    10 #include <utility>

    12 #include "nsIVariant.h"

    13 #include "nsString.h"

    14 #include "nsTArray.h"

    16 /**

    17  * This class is used by the storage module whenever an nsIVariant needs to be

    18  * returned.  We provide traits for the basic sqlite types to make use easier.

    19  * The following types map to the indicated sqlite type:

    20  * int64_t   -> INTEGER (use IntegerVariant)

    21  * double    -> FLOAT (use FloatVariant)

    22  * nsString  -> TEXT (use TextVariant)

    23  * nsCString -> TEXT (use UTF8TextVariant)

    24  * uint8_t[] -> BLOB (use BlobVariant)

    25  * nullptr   -> NULL (use NullVariant)

    26  */

    28 namespace mozilla {

    29 namespace storage {

    31 ////////////////////////////////////////////////////////////////////////////////

    32 //// Base Class

    34 class Variant_base : public nsIVariant

    35 {

    36 public:

    37   NS_DECL_THREADSAFE_ISUPPORTS

    38   NS_DECL_NSIVARIANT

    40 protected:

    41   virtual ~Variant_base() { }

    42 };

    44 ////////////////////////////////////////////////////////////////////////////////

    45 //// Traits

    47 /**

    48  * Generics

    49  */

    51 template <typename DataType>

    52 struct variant_traits

    53 {

    54   static inline uint16_t type() { return nsIDataType::VTYPE_EMPTY; }

    55 };

    57 template <typename DataType, bool Adopting=false>

    58 struct variant_storage_traits

    59 {

    60   typedef DataType ConstructorType;

    61   typedef DataType StorageType;

    62   static inline void storage_conversion(const ConstructorType aData, StorageType* _storage)

    63   {

    64     *_storage = aData;

    65   }

    67   static inline void destroy(const StorageType& _storage)

    68   { }

    69 };

    71 #define NO_CONVERSION return NS_ERROR_CANNOT_CONVERT_DATA;

    73 template <typename DataType, bool Adopting=false>

    74 struct variant_integer_traits

    75 {

    76   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;

    77   static inline nsresult asInt32(const StorageType &, int32_t *) { NO_CONVERSION }

    78   static inline nsresult asInt64(const StorageType &, int64_t *) { NO_CONVERSION }

    79 };

    81 template <typename DataType, bool Adopting=false>

    82 struct variant_float_traits

    83 {

    84   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;

    85   static inline nsresult asDouble(const StorageType &, double *) { NO_CONVERSION }

    86 };

    88 template <typename DataType, bool Adopting=false>

    89 struct variant_text_traits

    90 {

    91   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;

    92   static inline nsresult asUTF8String(const StorageType &, nsACString &) { NO_CONVERSION }

    93   static inline nsresult asString(const StorageType &, nsAString &) { NO_CONVERSION }

    94 };

    96 template <typename DataType, bool Adopting=false>

    97 struct variant_blob_traits

    98 {

    99   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;

   100   static inline nsresult asArray(const StorageType &, uint16_t *, uint32_t *, void **)

   101   { NO_CONVERSION }

   102 };

   104 #undef NO_CONVERSION

   106 /**

   107  * INTEGER types

   108  */

   110 template < >

   111 struct variant_traits<int64_t>

   112 {

   113   static inline uint16_t type() { return nsIDataType::VTYPE_INT64; }

   114 };

   115 template < >

   116 struct variant_integer_traits<int64_t>

   117 {

   118   static inline nsresult asInt32(int64_t aValue,

   119                                  int32_t *_result)

   120   {

   121     if (aValue > INT32_MAX || aValue < INT32_MIN)

   122       return NS_ERROR_CANNOT_CONVERT_DATA;

   124     *_result = static_cast<int32_t>(aValue);

   125     return NS_OK;

   126   }

   127   static inline nsresult asInt64(int64_t aValue,

   128                                  int64_t *_result)

   129   {

   130     *_result = aValue;

   131     return NS_OK;

   132   }

   133 };

   134 // xpcvariant just calls get double for integers...

   135 template < >

   136 struct variant_float_traits<int64_t>

   137 {

   138   static inline nsresult asDouble(int64_t aValue,

   139                                   double *_result)

   140   {

   141     *_result = double(aValue);

   142     return NS_OK;

   143   }

   144 };

   146 /**

   147  * FLOAT types

   148  */

   150 template < >

   151 struct variant_traits<double>

   152 {

   153   static inline uint16_t type() { return nsIDataType::VTYPE_DOUBLE; }

   154 };

   155 template < >

   156 struct variant_float_traits<double>

   157 {

   158   static inline nsresult asDouble(double aValue,

   159                                   double *_result)

   160   {

   161     *_result = aValue;

   162     return NS_OK;

   163   }

   164 };

   166 /**

   167  * TEXT types

   168  */

   170 template < >

   171 struct variant_traits<nsString>

   172 {

   173   static inline uint16_t type() { return nsIDataType::VTYPE_ASTRING; }

   174 };

   175 template < >

   176 struct variant_storage_traits<nsString>

   177 {

   178   typedef const nsAString & ConstructorType;

   179   typedef nsString StorageType;

   180   static inline void storage_conversion(ConstructorType aText, StorageType* _outData)

   181   {

   182     *_outData = aText;

   183   }

   184   static inline void destroy(const StorageType& _outData)

   185   { }

   186 };

   187 template < >

   188 struct variant_text_traits<nsString>

   189 {

   190   static inline nsresult asUTF8String(const nsString &aValue,

   191                                       nsACString &_result)

   192   {

   193     CopyUTF16toUTF8(aValue, _result);

   194     return NS_OK;

   195   }

   196   static inline nsresult asString(const nsString &aValue,

   197                                   nsAString &_result)

   198   {

   199     _result = aValue;

   200     return NS_OK;

   201   }

   202 };

   204 template < >

   205 struct variant_traits<nsCString>

   206 {

   207   static inline uint16_t type() { return nsIDataType::VTYPE_UTF8STRING; }

   208 };

   209 template < >

   210 struct variant_storage_traits<nsCString>

   211 {

   212   typedef const nsACString & ConstructorType;

   213   typedef nsCString StorageType;

   214   static inline void storage_conversion(ConstructorType aText, StorageType* _outData)

   215   {

   216     *_outData = aText;

   217   }

   218   static inline void destroy(const StorageType &aData)

   219   { }

   220 };

   221 template < >

   222 struct variant_text_traits<nsCString>

   223 {

   224   static inline nsresult asUTF8String(const nsCString &aValue,

   225                                       nsACString &_result)

   226   {

   227     _result = aValue;

   228     return NS_OK;

   229   }

   230   static inline nsresult asString(const nsCString &aValue,

   231                                   nsAString &_result)

   232   {

   233     CopyUTF8toUTF16(aValue, _result);

   234     return NS_OK;

   235   }

   236 };

   238 /**

   239  * BLOB types

   240  */

   242 template < >

   243 struct variant_traits<uint8_t[]>

   244 {

   245   static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; }

   246 };

   247 template < >

   248 struct variant_storage_traits<uint8_t[], false>

   249 {

   250   typedef std::pair<const void *, int> ConstructorType;

   251   typedef FallibleTArray<uint8_t> StorageType;

   252   static inline void storage_conversion(ConstructorType aBlob, StorageType* _outData)

   253   {

   254     _outData->Clear();

   255     _outData->SetCapacity(aBlob.second);

   256     (void)_outData->AppendElements(static_cast<const uint8_t *>(aBlob.first),

   257                                    aBlob.second);

   258   }

   259   static inline void destroy(const StorageType& _outData)

   260   { }

   261 };

   262 template < >

   263 struct variant_storage_traits<uint8_t[], true>

   264 {

   265   typedef std::pair<uint8_t *, int> ConstructorType;

   266   typedef std::pair<uint8_t *, int> StorageType;

   267   static inline void storage_conversion(ConstructorType aBlob, StorageType* _outData)

   268   {

   269     *_outData = aBlob;

   270   }

   271   static inline void destroy(StorageType &aData)

   272   {

   273     if (aData.first) {

   274       NS_Free(aData.first);

   275       aData.first = nullptr;

   276     }

   277   }

   278 };

   279 template < >

   280 struct variant_blob_traits<uint8_t[], false>

   281 {

   282   static inline nsresult asArray(FallibleTArray<uint8_t> &aData,

   283                                  uint16_t *_type,

   284                                  uint32_t *_size,

   285                                  void **_result)

   286   {

   287     // For empty blobs, we return nullptr.

   288     if (aData.Length() == 0) {

   289       *_result = nullptr;

   290       *_type = nsIDataType::VTYPE_UINT8;

   291       *_size = 0;

   292       return NS_OK;

   293     }

   295     // Otherwise, we copy the array.

   296     *_result = nsMemory::Clone(aData.Elements(), aData.Length() * sizeof(uint8_t));

   297     NS_ENSURE_TRUE(*_result, NS_ERROR_OUT_OF_MEMORY);

   299     // Set type and size

   300     *_type = nsIDataType::VTYPE_UINT8;

   301     *_size = aData.Length();

   302     return NS_OK;

   303   }

   304 };

   306 template < >

   307 struct variant_blob_traits<uint8_t[], true>

   308 {

   309   static inline nsresult asArray(std::pair<uint8_t *, int> &aData,

   310                                  uint16_t *_type,

   311                                  uint32_t *_size,

   312                                  void **_result)

   313   {

   314     // For empty blobs, we return nullptr.

   315     if (aData.second == 0) {

   316       *_result = nullptr;

   317       *_type = nsIDataType::VTYPE_UINT8;

   318       *_size = 0;

   319       return NS_OK;

   320     }

   322     // Otherwise, transfer the data out.

   323     *_result = aData.first;

   324     aData.first = nullptr;

   325     MOZ_ASSERT(*_result); // We asked for it twice, better not use adopting!

   327     // Set type and size

   328     *_type = nsIDataType::VTYPE_UINT8;

   329     *_size = aData.second;

   330     return NS_OK;

   331   }

   332 };

   334 /**

   335  * nullptr type

   336  */

   338 class NullVariant : public Variant_base

   339 {

   340 public:

   341   NS_IMETHOD GetDataType(uint16_t *_type)

   342   {

   343     NS_ENSURE_ARG_POINTER(_type);

   344     *_type = nsIDataType::VTYPE_EMPTY;

   345     return NS_OK;

   346   }

   348   NS_IMETHOD GetAsAUTF8String(nsACString &_str)

   349   {

   350     // Return a void string.

   351     _str.Truncate(0);

   352     _str.SetIsVoid(true);

   353     return NS_OK;

   354   }

   356   NS_IMETHOD GetAsAString(nsAString &_str)

   357   {

   358     // Return a void string.

   359     _str.Truncate(0);

   360     _str.SetIsVoid(true);

   361     return NS_OK;

   362   }

   363 };

   365 ////////////////////////////////////////////////////////////////////////////////

   366 //// Template Implementation

   368 template <typename DataType, bool Adopting=false>

   369 class Variant : public Variant_base

   370 {

   371   ~Variant()

   372   {

   373     variant_storage_traits<DataType, Adopting>::destroy(mData);

   374   }

   376 public:

   377   Variant(const typename variant_storage_traits<DataType, Adopting>::ConstructorType aData)

   378   {

   379     variant_storage_traits<DataType, Adopting>::storage_conversion(aData, &mData);

   380   }

   382   NS_IMETHOD GetDataType(uint16_t *_type)

   383   {

   384     *_type = variant_traits<DataType>::type();

   385     return NS_OK;

   386   }

   387   NS_IMETHOD GetAsInt32(int32_t *_integer)

   388   {

   389     return variant_integer_traits<DataType, Adopting>::asInt32(mData, _integer);

   390   }

   392   NS_IMETHOD GetAsInt64(int64_t *_integer)

   393   {

   394     return variant_integer_traits<DataType, Adopting>::asInt64(mData, _integer);

   395   }

   397   NS_IMETHOD GetAsDouble(double *_double)

   398   {

   399     return variant_float_traits<DataType, Adopting>::asDouble(mData, _double);

   400   }

   402   NS_IMETHOD GetAsAUTF8String(nsACString &_str)

   403   {

   404     return variant_text_traits<DataType, Adopting>::asUTF8String(mData, _str);

   405   }

   407   NS_IMETHOD GetAsAString(nsAString &_str)

   408   {

   409     return variant_text_traits<DataType, Adopting>::asString(mData, _str);

   410   }

   412   NS_IMETHOD GetAsArray(uint16_t *_type,

   413                         nsIID *,

   414                         uint32_t *_size,

   415                         void **_data)

   416   {

   417     return variant_blob_traits<DataType, Adopting>::asArray(mData, _type, _size, _data);

   418   }

   420 private:

   421   typename variant_storage_traits<DataType, Adopting>::StorageType mData;

   422 };

   424 ////////////////////////////////////////////////////////////////////////////////

   425 //// Handy typedefs!  Use these for the right mapping.

   427 typedef Variant<int64_t> IntegerVariant;

   428 typedef Variant<double> FloatVariant;

   429 typedef Variant<nsString> TextVariant;

   430 typedef Variant<nsCString> UTF8TextVariant;

   431 typedef Variant<uint8_t[], false> BlobVariant;

   432 typedef Variant<uint8_t[], true> AdoptedBlobVariant;

   434 } // namespace storage

   435 } // namespace mozilla

   437 #include "Variant_inl.h"

   439 #endif // mozilla_storage_Variant_h__

The Tor Browser / file revision

storage/src/Variant.h@6474c204b198

storage/src/Variant.h