michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ :
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef mozilla_storage_Variant_h__
michael@0: #define mozilla_storage_Variant_h__
michael@0: 
michael@0: #include <utility>
michael@0: 
michael@0: #include "nsIVariant.h"
michael@0: #include "nsString.h"
michael@0: #include "nsTArray.h"
michael@0: 
michael@0: /**
michael@0:  * This class is used by the storage module whenever an nsIVariant needs to be
michael@0:  * returned.  We provide traits for the basic sqlite types to make use easier.
michael@0:  * The following types map to the indicated sqlite type:
michael@0:  * int64_t   -> INTEGER (use IntegerVariant)
michael@0:  * double    -> FLOAT (use FloatVariant)
michael@0:  * nsString  -> TEXT (use TextVariant)
michael@0:  * nsCString -> TEXT (use UTF8TextVariant)
michael@0:  * uint8_t[] -> BLOB (use BlobVariant)
michael@0:  * nullptr   -> NULL (use NullVariant)
michael@0:  */
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace storage {
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// Base Class
michael@0: 
michael@0: class Variant_base : public nsIVariant
michael@0: {
michael@0: public:
michael@0:   NS_DECL_THREADSAFE_ISUPPORTS
michael@0:   NS_DECL_NSIVARIANT
michael@0: 
michael@0: protected:
michael@0:   virtual ~Variant_base() { }
michael@0: };
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// Traits
michael@0: 
michael@0: /**
michael@0:  * Generics
michael@0:  */
michael@0: 
michael@0: template <typename DataType>
michael@0: struct variant_traits
michael@0: {
michael@0:   static inline uint16_t type() { return nsIDataType::VTYPE_EMPTY; }
michael@0: };
michael@0: 
michael@0: template <typename DataType, bool Adopting=false>
michael@0: struct variant_storage_traits
michael@0: {
michael@0:   typedef DataType ConstructorType;
michael@0:   typedef DataType StorageType;
michael@0:   static inline void storage_conversion(const ConstructorType aData, StorageType* _storage)
michael@0:   {
michael@0:     *_storage = aData;
michael@0:   }
michael@0: 
michael@0:   static inline void destroy(const StorageType& _storage)
michael@0:   { }
michael@0: };
michael@0: 
michael@0: #define NO_CONVERSION return NS_ERROR_CANNOT_CONVERT_DATA;
michael@0: 
michael@0: template <typename DataType, bool Adopting=false>
michael@0: struct variant_integer_traits
michael@0: {
michael@0:   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;
michael@0:   static inline nsresult asInt32(const StorageType &, int32_t *) { NO_CONVERSION }
michael@0:   static inline nsresult asInt64(const StorageType &, int64_t *) { NO_CONVERSION }
michael@0: };
michael@0: 
michael@0: template <typename DataType, bool Adopting=false>
michael@0: struct variant_float_traits
michael@0: {
michael@0:   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;
michael@0:   static inline nsresult asDouble(const StorageType &, double *) { NO_CONVERSION }
michael@0: };
michael@0: 
michael@0: template <typename DataType, bool Adopting=false>
michael@0: struct variant_text_traits
michael@0: {
michael@0:   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;
michael@0:   static inline nsresult asUTF8String(const StorageType &, nsACString &) { NO_CONVERSION }
michael@0:   static inline nsresult asString(const StorageType &, nsAString &) { NO_CONVERSION }
michael@0: };
michael@0: 
michael@0: template <typename DataType, bool Adopting=false>
michael@0: struct variant_blob_traits
michael@0: {
michael@0:   typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType;
michael@0:   static inline nsresult asArray(const StorageType &, uint16_t *, uint32_t *, void **)
michael@0:   { NO_CONVERSION }
michael@0: };
michael@0: 
michael@0: #undef NO_CONVERSION
michael@0: 
michael@0: /**
michael@0:  * INTEGER types
michael@0:  */
michael@0: 
michael@0: template < >
michael@0: struct variant_traits<int64_t>
michael@0: {
michael@0:   static inline uint16_t type() { return nsIDataType::VTYPE_INT64; }
michael@0: };
michael@0: template < >
michael@0: struct variant_integer_traits<int64_t>
michael@0: {
michael@0:   static inline nsresult asInt32(int64_t aValue,
michael@0:                                  int32_t *_result)
michael@0:   {
michael@0:     if (aValue > INT32_MAX || aValue < INT32_MIN)
michael@0:       return NS_ERROR_CANNOT_CONVERT_DATA;
michael@0: 
michael@0:     *_result = static_cast<int32_t>(aValue);
michael@0:     return NS_OK;
michael@0:   }
michael@0:   static inline nsresult asInt64(int64_t aValue,
michael@0:                                  int64_t *_result)
michael@0:   {
michael@0:     *_result = aValue;
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: // xpcvariant just calls get double for integers...
michael@0: template < >
michael@0: struct variant_float_traits<int64_t>
michael@0: {
michael@0:   static inline nsresult asDouble(int64_t aValue,
michael@0:                                   double *_result)
michael@0:   {
michael@0:     *_result = double(aValue);
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * FLOAT types
michael@0:  */
michael@0: 
michael@0: template < >
michael@0: struct variant_traits<double>
michael@0: {
michael@0:   static inline uint16_t type() { return nsIDataType::VTYPE_DOUBLE; }
michael@0: };
michael@0: template < >
michael@0: struct variant_float_traits<double>
michael@0: {
michael@0:   static inline nsresult asDouble(double aValue,
michael@0:                                   double *_result)
michael@0:   {
michael@0:     *_result = aValue;
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * TEXT types
michael@0:  */
michael@0: 
michael@0: template < >
michael@0: struct variant_traits<nsString>
michael@0: {
michael@0:   static inline uint16_t type() { return nsIDataType::VTYPE_ASTRING; }
michael@0: };
michael@0: template < >
michael@0: struct variant_storage_traits<nsString>
michael@0: {
michael@0:   typedef const nsAString & ConstructorType;
michael@0:   typedef nsString StorageType;
michael@0:   static inline void storage_conversion(ConstructorType aText, StorageType* _outData)
michael@0:   {
michael@0:     *_outData = aText;
michael@0:   }
michael@0:   static inline void destroy(const StorageType& _outData)
michael@0:   { }
michael@0: };
michael@0: template < >
michael@0: struct variant_text_traits<nsString>
michael@0: {
michael@0:   static inline nsresult asUTF8String(const nsString &aValue,
michael@0:                                       nsACString &_result)
michael@0:   {
michael@0:     CopyUTF16toUTF8(aValue, _result);
michael@0:     return NS_OK;
michael@0:   }
michael@0:   static inline nsresult asString(const nsString &aValue,
michael@0:                                   nsAString &_result)
michael@0:   {
michael@0:     _result = aValue;
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: template < >
michael@0: struct variant_traits<nsCString>
michael@0: {
michael@0:   static inline uint16_t type() { return nsIDataType::VTYPE_UTF8STRING; }
michael@0: };
michael@0: template < >
michael@0: struct variant_storage_traits<nsCString>
michael@0: {
michael@0:   typedef const nsACString & ConstructorType;
michael@0:   typedef nsCString StorageType;
michael@0:   static inline void storage_conversion(ConstructorType aText, StorageType* _outData)
michael@0:   {
michael@0:     *_outData = aText;
michael@0:   }
michael@0:   static inline void destroy(const StorageType &aData)
michael@0:   { }
michael@0: };
michael@0: template < >
michael@0: struct variant_text_traits<nsCString>
michael@0: {
michael@0:   static inline nsresult asUTF8String(const nsCString &aValue,
michael@0:                                       nsACString &_result)
michael@0:   {
michael@0:     _result = aValue;
michael@0:     return NS_OK;
michael@0:   }
michael@0:   static inline nsresult asString(const nsCString &aValue,
michael@0:                                   nsAString &_result)
michael@0:   {
michael@0:     CopyUTF8toUTF16(aValue, _result);
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * BLOB types
michael@0:  */
michael@0: 
michael@0: template < >
michael@0: struct variant_traits<uint8_t[]>
michael@0: {
michael@0:   static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; }
michael@0: };
michael@0: template < >
michael@0: struct variant_storage_traits<uint8_t[], false>
michael@0: {
michael@0:   typedef std::pair<const void *, int> ConstructorType;
michael@0:   typedef FallibleTArray<uint8_t> StorageType;
michael@0:   static inline void storage_conversion(ConstructorType aBlob, StorageType* _outData)
michael@0:   {
michael@0:     _outData->Clear();
michael@0:     _outData->SetCapacity(aBlob.second);
michael@0:     (void)_outData->AppendElements(static_cast<const uint8_t *>(aBlob.first),
michael@0:                                    aBlob.second);
michael@0:   }
michael@0:   static inline void destroy(const StorageType& _outData)
michael@0:   { }
michael@0: };
michael@0: template < >
michael@0: struct variant_storage_traits<uint8_t[], true>
michael@0: {
michael@0:   typedef std::pair<uint8_t *, int> ConstructorType;
michael@0:   typedef std::pair<uint8_t *, int> StorageType;
michael@0:   static inline void storage_conversion(ConstructorType aBlob, StorageType* _outData)
michael@0:   {
michael@0:     *_outData = aBlob;
michael@0:   }
michael@0:   static inline void destroy(StorageType &aData)
michael@0:   {
michael@0:     if (aData.first) {
michael@0:       NS_Free(aData.first);
michael@0:       aData.first = nullptr;
michael@0:     }
michael@0:   }
michael@0: };
michael@0: template < >
michael@0: struct variant_blob_traits<uint8_t[], false>
michael@0: {
michael@0:   static inline nsresult asArray(FallibleTArray<uint8_t> &aData,
michael@0:                                  uint16_t *_type,
michael@0:                                  uint32_t *_size,
michael@0:                                  void **_result)
michael@0:   {
michael@0:     // For empty blobs, we return nullptr.
michael@0:     if (aData.Length() == 0) {
michael@0:       *_result = nullptr;
michael@0:       *_type = nsIDataType::VTYPE_UINT8;
michael@0:       *_size = 0;
michael@0:       return NS_OK;
michael@0:     }
michael@0: 
michael@0:     // Otherwise, we copy the array.
michael@0:     *_result = nsMemory::Clone(aData.Elements(), aData.Length() * sizeof(uint8_t));
michael@0:     NS_ENSURE_TRUE(*_result, NS_ERROR_OUT_OF_MEMORY);
michael@0: 
michael@0:     // Set type and size
michael@0:     *_type = nsIDataType::VTYPE_UINT8;
michael@0:     *_size = aData.Length();
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: template < >
michael@0: struct variant_blob_traits<uint8_t[], true>
michael@0: {
michael@0:   static inline nsresult asArray(std::pair<uint8_t *, int> &aData,
michael@0:                                  uint16_t *_type,
michael@0:                                  uint32_t *_size,
michael@0:                                  void **_result)
michael@0:   {
michael@0:     // For empty blobs, we return nullptr.
michael@0:     if (aData.second == 0) {
michael@0:       *_result = nullptr;
michael@0:       *_type = nsIDataType::VTYPE_UINT8;
michael@0:       *_size = 0;
michael@0:       return NS_OK;
michael@0:     }
michael@0: 
michael@0:     // Otherwise, transfer the data out.
michael@0:     *_result = aData.first;
michael@0:     aData.first = nullptr;
michael@0:     MOZ_ASSERT(*_result); // We asked for it twice, better not use adopting!
michael@0: 
michael@0:     // Set type and size
michael@0:     *_type = nsIDataType::VTYPE_UINT8;
michael@0:     *_size = aData.second;
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * nullptr type
michael@0:  */
michael@0: 
michael@0: class NullVariant : public Variant_base
michael@0: {
michael@0: public:
michael@0:   NS_IMETHOD GetDataType(uint16_t *_type)
michael@0:   {
michael@0:     NS_ENSURE_ARG_POINTER(_type);
michael@0:     *_type = nsIDataType::VTYPE_EMPTY;
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsAUTF8String(nsACString &_str)
michael@0:   {
michael@0:     // Return a void string.
michael@0:     _str.Truncate(0);
michael@0:     _str.SetIsVoid(true);
michael@0:     return NS_OK;
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsAString(nsAString &_str)
michael@0:   {
michael@0:     // Return a void string.
michael@0:     _str.Truncate(0);
michael@0:     _str.SetIsVoid(true);
michael@0:     return NS_OK;
michael@0:   }
michael@0: };
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// Template Implementation
michael@0: 
michael@0: template <typename DataType, bool Adopting=false>
michael@0: class Variant : public Variant_base
michael@0: {
michael@0:   ~Variant()
michael@0:   {
michael@0:     variant_storage_traits<DataType, Adopting>::destroy(mData);
michael@0:   }
michael@0: 
michael@0: public:
michael@0:   Variant(const typename variant_storage_traits<DataType, Adopting>::ConstructorType aData)
michael@0:   {
michael@0:     variant_storage_traits<DataType, Adopting>::storage_conversion(aData, &mData);
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetDataType(uint16_t *_type)
michael@0:   {
michael@0:     *_type = variant_traits<DataType>::type();
michael@0:     return NS_OK;
michael@0:   }
michael@0:   NS_IMETHOD GetAsInt32(int32_t *_integer)
michael@0:   {
michael@0:     return variant_integer_traits<DataType, Adopting>::asInt32(mData, _integer);
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsInt64(int64_t *_integer)
michael@0:   {
michael@0:     return variant_integer_traits<DataType, Adopting>::asInt64(mData, _integer);
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsDouble(double *_double)
michael@0:   {
michael@0:     return variant_float_traits<DataType, Adopting>::asDouble(mData, _double);
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsAUTF8String(nsACString &_str)
michael@0:   {
michael@0:     return variant_text_traits<DataType, Adopting>::asUTF8String(mData, _str);
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsAString(nsAString &_str)
michael@0:   {
michael@0:     return variant_text_traits<DataType, Adopting>::asString(mData, _str);
michael@0:   }
michael@0: 
michael@0:   NS_IMETHOD GetAsArray(uint16_t *_type,
michael@0:                         nsIID *,
michael@0:                         uint32_t *_size,
michael@0:                         void **_data)
michael@0:   {
michael@0:     return variant_blob_traits<DataType, Adopting>::asArray(mData, _type, _size, _data);
michael@0:   }
michael@0: 
michael@0: private:
michael@0:   typename variant_storage_traits<DataType, Adopting>::StorageType mData;
michael@0: };
michael@0: 
michael@0: ////////////////////////////////////////////////////////////////////////////////
michael@0: //// Handy typedefs!  Use these for the right mapping.
michael@0: 
michael@0: typedef Variant<int64_t> IntegerVariant;
michael@0: typedef Variant<double> FloatVariant;
michael@0: typedef Variant<nsString> TextVariant;
michael@0: typedef Variant<nsCString> UTF8TextVariant;
michael@0: typedef Variant<uint8_t[], false> BlobVariant;
michael@0: typedef Variant<uint8_t[], true> AdoptedBlobVariant;
michael@0: 
michael@0: } // namespace storage
michael@0: } // namespace mozilla
michael@0: 
michael@0: #include "Variant_inl.h"
michael@0: 
michael@0: #endif // mozilla_storage_Variant_h__