/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- * vim: sw=2 ts=2 et lcs=trail\:.,tab\:>~ : * 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 mozilla_storage_Variant_h__ #define mozilla_storage_Variant_h__ #include <utility> #include "nsIVariant.h" #include "nsString.h" #include "nsTArray.h" #define VARIANT_BASE_IID \ { /* 78888042-0fa3-4f7a-8b19-7996f99bf1aa */ \ 0x78888042, 0x0fa3, 0x4f7a, \ { 0x8b, 0x19, 0x79, 0x96, 0xf9, 0x9b, 0xf1, 0xaa } \ } /** * This class is used by the storage module whenever an nsIVariant needs to be * returned. We provide traits for the basic sqlite types to make use easier. * The following types map to the indicated sqlite type: * int64_t -> INTEGER (use IntegerVariant) * double -> FLOAT (use FloatVariant) * nsString -> TEXT (use TextVariant) * nsCString -> TEXT (use UTF8TextVariant) * uint8_t[] -> BLOB (use BlobVariant) * nullptr -> NULL (use NullVariant) */ namespace mozilla { namespace storage { //////////////////////////////////////////////////////////////////////////////// //// Base Class class Variant_base : public nsIVariant { public: NS_DECL_THREADSAFE_ISUPPORTS NS_DECL_NSIVARIANT NS_DECLARE_STATIC_IID_ACCESSOR(VARIANT_BASE_IID) protected: virtual ~Variant_base() { } }; NS_DEFINE_STATIC_IID_ACCESSOR(Variant_base, VARIANT_BASE_IID) //////////////////////////////////////////////////////////////////////////////// //// Traits /** * Generics */ template <typename DataType> struct variant_traits { static inline uint16_t type() { return nsIDataType::VTYPE_EMPTY; } }; template <typename DataType, bool Adopting=false> struct variant_storage_traits { typedef DataType ConstructorType; typedef DataType StorageType; static inline void storage_conversion(const ConstructorType aData, StorageType* _storage) { *_storage = aData; } static inline void destroy(const StorageType& _storage) { } }; #define NO_CONVERSION return NS_ERROR_CANNOT_CONVERT_DATA; template <typename DataType, bool Adopting=false> struct variant_integer_traits { typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType; static inline nsresult asInt32(const StorageType &, int32_t *) { NO_CONVERSION } static inline nsresult asInt64(const StorageType &, int64_t *) { NO_CONVERSION } }; template <typename DataType, bool Adopting=false> struct variant_float_traits { typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType; static inline nsresult asDouble(const StorageType &, double *) { NO_CONVERSION } }; template <typename DataType, bool Adopting=false> struct variant_text_traits { typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType; static inline nsresult asUTF8String(const StorageType &, nsACString &) { NO_CONVERSION } static inline nsresult asString(const StorageType &, nsAString &) { NO_CONVERSION } }; template <typename DataType, bool Adopting=false> struct variant_blob_traits { typedef typename variant_storage_traits<DataType, Adopting>::StorageType StorageType; static inline nsresult asArray(const StorageType &, uint16_t *, uint32_t *, void **) { NO_CONVERSION } }; #undef NO_CONVERSION /** * INTEGER types */ template < > struct variant_traits<int64_t> { static inline uint16_t type() { return nsIDataType::VTYPE_INT64; } }; template < > struct variant_integer_traits<int64_t> { static inline nsresult asInt32(int64_t aValue, int32_t *_result) { if (aValue > INT32_MAX || aValue < INT32_MIN) return NS_ERROR_CANNOT_CONVERT_DATA; *_result = static_cast<int32_t>(aValue); return NS_OK; } static inline nsresult asInt64(int64_t aValue, int64_t *_result) { *_result = aValue; return NS_OK; } }; // xpcvariant just calls get double for integers... template < > struct variant_float_traits<int64_t> { static inline nsresult asDouble(int64_t aValue, double *_result) { *_result = double(aValue); return NS_OK; } }; /** * FLOAT types */ template < > struct variant_traits<double> { static inline uint16_t type() { return nsIDataType::VTYPE_DOUBLE; } }; template < > struct variant_float_traits<double> { static inline nsresult asDouble(double aValue, double *_result) { *_result = aValue; return NS_OK; } }; /** * TEXT types */ template < > struct variant_traits<nsString> { static inline uint16_t type() { return nsIDataType::VTYPE_ASTRING; } }; template < > struct variant_storage_traits<nsString> { typedef const nsAString & ConstructorType; typedef nsString StorageType; static inline void storage_conversion(ConstructorType aText, StorageType* _outData) { *_outData = aText; } static inline void destroy(const StorageType& _outData) { } }; template < > struct variant_text_traits<nsString> { static inline nsresult asUTF8String(const nsString &aValue, nsACString &_result) { CopyUTF16toUTF8(aValue, _result); return NS_OK; } static inline nsresult asString(const nsString &aValue, nsAString &_result) { _result = aValue; return NS_OK; } }; template < > struct variant_traits<nsCString> { static inline uint16_t type() { return nsIDataType::VTYPE_UTF8STRING; } }; template < > struct variant_storage_traits<nsCString> { typedef const nsACString & ConstructorType; typedef nsCString StorageType; static inline void storage_conversion(ConstructorType aText, StorageType* _outData) { *_outData = aText; } static inline void destroy(const StorageType &aData) { } }; template < > struct variant_text_traits<nsCString> { static inline nsresult asUTF8String(const nsCString &aValue, nsACString &_result) { _result = aValue; return NS_OK; } static inline nsresult asString(const nsCString &aValue, nsAString &_result) { CopyUTF8toUTF16(aValue, _result); return NS_OK; } }; /** * BLOB types */ template < > struct variant_traits<uint8_t[]> { static inline uint16_t type() { return nsIDataType::VTYPE_ARRAY; } }; template < > struct variant_storage_traits<uint8_t[], false> { typedef std::pair<const void *, int> ConstructorType; typedef FallibleTArray<uint8_t> StorageType; static inline void storage_conversion(ConstructorType aBlob, StorageType* _outData) { _outData->Clear(); (void)_outData->AppendElements(static_cast<const uint8_t *>(aBlob.first), aBlob.second, fallible); } static inline void destroy(const StorageType& _outData) { } }; template < > struct variant_storage_traits<uint8_t[], true> { typedef std::pair<uint8_t *, int> ConstructorType; typedef std::pair<uint8_t *, int> StorageType; static inline void storage_conversion(ConstructorType aBlob, StorageType* _outData) { *_outData = aBlob; } static inline void destroy(StorageType &aData) { if (aData.first) { free(aData.first); aData.first = nullptr; } } }; template < > struct variant_blob_traits<uint8_t[], false> { static inline nsresult asArray(FallibleTArray<uint8_t> &aData, uint16_t *_type, uint32_t *_size, void **_result) { // For empty blobs, we return nullptr. if (aData.Length() == 0) { *_result = nullptr; *_type = nsIDataType::VTYPE_UINT8; *_size = 0; return NS_OK; } // Otherwise, we copy the array. *_result = nsMemory::Clone(aData.Elements(), aData.Length() * sizeof(uint8_t)); NS_ENSURE_TRUE(*_result, NS_ERROR_OUT_OF_MEMORY); // Set type and size *_type = nsIDataType::VTYPE_UINT8; *_size = aData.Length(); return NS_OK; } }; template < > struct variant_blob_traits<uint8_t[], true> { static inline nsresult asArray(std::pair<uint8_t *, int> &aData, uint16_t *_type, uint32_t *_size, void **_result) { // For empty blobs, we return nullptr. if (aData.second == 0) { *_result = nullptr; *_type = nsIDataType::VTYPE_UINT8; *_size = 0; return NS_OK; } // Otherwise, transfer the data out. *_result = aData.first; aData.first = nullptr; MOZ_ASSERT(*_result); // We asked for it twice, better not use adopting! // Set type and size *_type = nsIDataType::VTYPE_UINT8; *_size = aData.second; return NS_OK; } }; /** * nullptr type */ class NullVariant : public Variant_base { public: NS_IMETHOD GetDataType(uint16_t *_type) { NS_ENSURE_ARG_POINTER(_type); *_type = nsIDataType::VTYPE_EMPTY; return NS_OK; } NS_IMETHOD GetAsAUTF8String(nsACString &_str) { // Return a void string. _str.SetIsVoid(true); return NS_OK; } NS_IMETHOD GetAsAString(nsAString &_str) { // Return a void string. _str.SetIsVoid(true); return NS_OK; } }; //////////////////////////////////////////////////////////////////////////////// //// Template Implementation template <typename DataType, bool Adopting=false> class Variant final : public Variant_base { ~Variant() { variant_storage_traits<DataType, Adopting>::destroy(mData); } public: explicit Variant(const typename variant_storage_traits<DataType, Adopting>::ConstructorType aData) { variant_storage_traits<DataType, Adopting>::storage_conversion(aData, &mData); } NS_IMETHOD GetDataType(uint16_t *_type) { *_type = variant_traits<DataType>::type(); return NS_OK; } NS_IMETHOD GetAsInt32(int32_t *_integer) { return variant_integer_traits<DataType, Adopting>::asInt32(mData, _integer); } NS_IMETHOD GetAsInt64(int64_t *_integer) { return variant_integer_traits<DataType, Adopting>::asInt64(mData, _integer); } NS_IMETHOD GetAsDouble(double *_double) { return variant_float_traits<DataType, Adopting>::asDouble(mData, _double); } NS_IMETHOD GetAsAUTF8String(nsACString &_str) { return variant_text_traits<DataType, Adopting>::asUTF8String(mData, _str); } NS_IMETHOD GetAsAString(nsAString &_str) { return variant_text_traits<DataType, Adopting>::asString(mData, _str); } NS_IMETHOD GetAsArray(uint16_t *_type, nsIID *, uint32_t *_size, void **_data) { return variant_blob_traits<DataType, Adopting>::asArray(mData, _type, _size, _data); } private: typename variant_storage_traits<DataType, Adopting>::StorageType mData; }; //////////////////////////////////////////////////////////////////////////////// //// Handy typedefs! Use these for the right mapping. typedef Variant<int64_t> IntegerVariant; typedef Variant<double> FloatVariant; typedef Variant<nsString> TextVariant; typedef Variant<nsCString> UTF8TextVariant; typedef Variant<uint8_t[], false> BlobVariant; typedef Variant<uint8_t[], true> AdoptedBlobVariant; } // namespace storage } // namespace mozilla #include "Variant_inl.h" #endif // mozilla_storage_Variant_h__