diff options
Diffstat (limited to 'cpp/include/Ice/StreamTraits.h')
| -rw-r--r-- | cpp/include/Ice/StreamTraits.h | 316 |
1 files changed, 151 insertions, 165 deletions
diff --git a/cpp/include/Ice/StreamTraits.h b/cpp/include/Ice/StreamTraits.h index 97638d5152b..00f38cb5819 100644 --- a/cpp/include/Ice/StreamTraits.h +++ b/cpp/include/Ice/StreamTraits.h @@ -15,7 +15,6 @@ #include <Ice/ObjectF.h> - namespace Ice { @@ -34,7 +33,7 @@ enum StreamTraitType StreamTraitTypeProxy, StreamTraitTypeClass, StreamTraitTypeUserException, - StreamTraitTypeUnknown + StreamTraitTypeCustom }; // @@ -42,58 +41,106 @@ enum StreamTraitType // // Optional data members or attribute is encoded with a specific // optional type. This optional type describes how the data is encoded -// and how it can be skiped by the un-marhsalling code if the optional +// and how it can be skipped by the un-marhsalling code if the optional // isn't known to the receiver. // enum OptionalType { - OptionalTypeF1 = 0, - OptionalTypeF2 = 1, - OptionalTypeF4 = 2, - OptionalTypeF8 = 3, - OptionalTypeSize = 4, - OptionalTypeVSize = 5, - OptionalTypeFSize = 6, - OptionalTypeEndMarker = 7 + OptionalTypeF1 = 0, // Fixed 1-byte encoding + OptionalTypeF2 = 1, // Fixed 2 bytes encoding + OptionalTypeF4 = 2, // Fixed 4 bytes encoding + OptionalTypeF8 = 3, // Fixed 8 bytes encoding + OptionalTypeSize = 4, // "Size encoding" on 1 to 5 bytes, e.g. enum, class identifier + OptionalTypeVSize = 5, // "Size encoding" on 1 to 5 bytes followed by data, e.g. string, fixed size struct, + // or containers whose size can be computed prior to marshaling + OptionalTypeFSize = 6, // Fixed size on 4 bytes followed by data, e.g. variable-size struct, container. + OptionalTypeEndMarker = 7 }; + // -// Base trait template. This doesn't actually do anything -- we just -// use it as a template that we can specialize. +// Is the provided type a container? +// For now, the implementation only checks if there is a T::iterator typedef +// using SFINAE +// +template<typename T> +struct IsContainer +{ + template<typename C> + static char test(typename C::iterator*); + + template<typename C> + static long test(...); + + static const bool value = sizeof(test<T>(0)) == sizeof(char); +}; + // -// Note that types which don't define a specialized trait will end up -// using this trait. The marshalling of unknown types assume that -// such traits are custom sequences. If not appropriate, a trait has -// to defined with the appropriate type. +// Is the provided type a map? +// For now, the implementation only checks if there is a T::mapped_type typedef +// using SFINAE // template<typename T> -struct StreamTrait +struct IsMap { - static const StreamTraitType type = StreamTraitTypeUnknown; - static const int minWireSize = 1; - static const OptionalType optionalType = OptionalTypeVSize; // Not used - static const bool isVariableLength = true; + template<typename C> + static char test(typename C::mapped_type*); + + template<typename C> + static long test(...); + + static const bool value = IsContainer<T>::value && sizeof(test<T>(0)) == sizeof(char); }; // -// StreamTrait specialization for std::vector +// Base trait template. +// Types with no specialized trait use this trait. // template<typename T> -struct StreamTrait< ::std::vector<T> > +struct StreamTrait { - static const StreamTraitType type = StreamTraitTypeSequence; + static const StreamTraitType type = IsMap<T>::value ? StreamTraitTypeDictionary : + (IsContainer<T>::value ? StreamTraitTypeSequence : StreamTraitTypeCustom); + + // + // When extracting a sequence<T> from a stream, we can ensure the + // stream as at least StreamTrait<T>::minWireSize * size bytes + // For containers, the minWireSize is 1 - just 1 byte for an empty container. + // static const int minWireSize = 1; - static const OptionalType optionalType = OptionalTypeVSize; // Not used but still need to be defined. - static const bool isVariableLength = true; + + // + // The OptionalType, for reading/writing optional T from/to the stream + // For containers, it can be either OptionalTypeVSize or OptionalTypeFSize + // depending on whether the contained element is fixed size or not. + // We can't easily compute it here, so we set optionalType to OptionalTypeEndMarker + // and compute the correct optionalType for the container in the StreamOptionalHelpers + // below. + // + static const OptionalType optionalType = OptionalTypeEndMarker; +}; + +template<typename T> +struct IsFixedLength +{ + typedef typename StreamTrait<T> Traits; + + static const bool value = (Traits::optionalType <= OptionalTypeF8) + || ((Traits::type == StreamTraitTypeStruct || Traits::type == StreamTraitTypeStructClass) + && Traits::optionalType == OptionalTypeVSize); }; +// +// StreamTrait specialization for array / range mapped sequences +// The type can be a std::pair<T, T> or a +// std::pair<IceUtil::ScopedArray<T>, std::pair<const T*, const T*> > +// template<typename T, typename U> struct StreamTrait< ::std::pair<T, U> > { static const StreamTraitType type = StreamTraitTypeSequence; static const int minWireSize = 1; - static const OptionalType optionalType = OptionalTypeVSize; // Not used but still need to be defined. - static const bool isVariableLength = true; + static const OptionalType optionalType = OptionalTypeEndMarker; }; // @@ -103,85 +150,72 @@ template<> struct StreamTrait<UserException> { static const StreamTraitType type = StreamTraitTypeUserException; -}; -// -// StreamTrait specialization for std::map. -// -template<typename K, typename V> -struct StreamTrait< ::std::map<K, V> > -{ - static const StreamTraitType type = StreamTraitTypeDictionary; - static const int minWireSize = 1; - static const OptionalType optionalType = OptionalTypeVSize; // Not used - static const bool isVariableLength = true; + // + // There is no sequence/dictionary of UserException (so no need for minWireSize) + // and no optional UserException (so no need for optionalType) + // }; + // // StreamTrait specialization for builtins (these are needed for sequence // marshalling to figure out the minWireSize of each built-in). // template<> -struct StreamTrait< bool> +struct StreamTrait<bool> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 1; static const OptionalType optionalType = OptionalTypeF1; - static const bool isVariableLength = false; }; template<> -struct StreamTrait< Byte> +struct StreamTrait<Byte> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 1; static const OptionalType optionalType = OptionalTypeF1; - static const bool isVariableLength = false; }; template<> -struct StreamTrait< Short> +struct StreamTrait<Short> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 2; static const OptionalType optionalType = OptionalTypeF2; - static const bool isVariableLength = false; }; template<> -struct StreamTrait< Int> +struct StreamTrait<Int> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 4; static const OptionalType optionalType = OptionalTypeF4; - static const bool isVariableLength = false; }; template<> -struct StreamTrait< Long> +struct StreamTrait<Long> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 8; static const OptionalType optionalType = OptionalTypeF8; - static const bool isVariableLength = false; }; template<> -struct StreamTrait< Float> +struct StreamTrait<Float> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 4; static const OptionalType optionalType = OptionalTypeF4; - static const bool isVariableLength = false; }; template<> -struct StreamTrait< Double> +struct StreamTrait<Double> { static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 8; static const OptionalType optionalType = OptionalTypeF8; - static const bool isVariableLength = false; }; template<> @@ -190,7 +224,6 @@ struct StreamTrait< ::std::string> static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 1; static const OptionalType optionalType = OptionalTypeVSize; - static const bool isVariableLength = true; }; template<> @@ -199,7 +232,6 @@ struct StreamTrait< ::std::wstring> static const StreamTraitType type = StreamTraitTypeBuiltin; static const int minWireSize = 1; static const OptionalType optionalType = OptionalTypeVSize; - static const bool isVariableLength = true; }; template<typename T> @@ -208,7 +240,6 @@ struct StreamTrait< ::IceInternal::ProxyHandle<T> > static const StreamTraitType type = StreamTraitTypeProxy; static const int minWireSize = 2; static const OptionalType optionalType = OptionalTypeFSize; - static const bool isVariableLength = true; }; template<typename T> @@ -217,48 +248,17 @@ struct StreamTrait< ::IceInternal::Handle<T> > static const StreamTraitType type = StreamTraitTypeClass; static const int minWireSize = 1; static const OptionalType optionalType = OptionalTypeSize; - static const bool isVariableLength = true; }; + // // StreamHelper templates used by streams to read and write data. // +// Base StreamHelper template; it must be specialized for each type template<typename T, StreamTraitType st> -struct StreamHelper -{ - template<class S> static inline void - write(S* stream, const T& v) - { - assert(false); - } - - template<class S> static inline void - read(S* stream, T& v) - { - assert(false); - } -}; - -template<typename T, StreamTraitType st, OptionalType ot> -struct StreamOptionalHelper -{ - static const OptionalType optionalType = ot; +struct StreamHelper; - template<class S> static inline void - write(S* stream, const T& v) - { - assert((ot != OptionalTypeVSize && ot != OptionalTypeFSize) || st == StreamTraitTypeBuiltin); - StreamHelper<T, st>::write(stream, v); - } - - template<class S> static inline void - read(S* stream, T& v) - { - assert((ot != OptionalTypeVSize && ot != OptionalTypeFSize) || st == StreamTraitTypeBuiltin); - StreamHelper<T, st>::read(stream, v); - } -}; // Helper for builtins, delegates read/write to the stream. template<typename T> @@ -355,7 +355,7 @@ struct StreamHelper<T, StreamTraitTypeSequence> template<class S> static inline void read(S* stream, T& v) { - Int sz = stream->readAndCheckSeqSize(StreamTrait<T>::minWireSize); + Int sz = stream->readAndCheckSeqSize(StreamTrait<T::value_type>::minWireSize); T(sz).swap(v); for(typename T::iterator p = v.begin(); p != v.end(); ++p) { @@ -417,11 +417,7 @@ struct StreamHelper<std::pair< ::std::vector<bool>::const_iterator, } } - template<class S> static inline void - read(S* stream, std::pair< ::std::vector<bool>::const_iterator, ::std::vector<bool>::const_iterator>&) - { - assert(false); // Only used for marshaling. - } + // no read: only used for marshaling }; // Helper for zero-copy array sequence parameters @@ -429,16 +425,12 @@ template<typename T> struct StreamHelper<std::pair<IceUtil::ScopedArray<T>, std::pair<const T*, const T*> >, StreamTraitTypeSequence> { template<class S> static inline void - write(S* stream, const std::pair<IceUtil::ScopedArray<T>, std::pair<const T*, const T*> > & v) - { - assert(false); // Only used to un-marshal - } - - template<class S> static inline void read(S* stream, std::pair<IceUtil::ScopedArray<T>, std::pair<const T*, const T*> >& v) { v.first.reset(stream->read(v.second)); } + + // no write: only used for unmarshaling }; // Helper for dictionaries @@ -460,6 +452,7 @@ struct StreamHelper<T, StreamTraitTypeDictionary> read(S* stream, T& v) { Int sz = stream->readSize(); + v.clear(); while(sz--) { typename T::value_type p; @@ -480,11 +473,7 @@ struct StreamHelper<T, StreamTraitTypeUserException> stream->writeException(v); } - template<class S> static inline void - read(S* stream, T& v) - { - assert(false); - } + // no read: only used for marshaling }; // Helper for proxies @@ -521,16 +510,34 @@ struct StreamHelper<T, StreamTraitTypeClass> } }; -// Helper for unknown types, assume custom sequences. -template<typename T> -struct StreamHelper<T, StreamTraitTypeUnknown> : StreamHelper<T, StreamTraitTypeSequence> -{ -}; // // Helpers to read/write optional attributes or members. // +// Base helper +template<typename T, StreamTraitType st, OptionalType ot> +struct StreamOptionalHelper +{ + static const OptionalType optionalType = ot; + + template<class S> static inline void + write(S* stream, const T& v) + { + assert((ot != OptionalTypeVSize && ot != OptionalTypeFSize && ot != OptionalTypeEndMarker) + || st == StreamTraitTypeBuiltin); + StreamHelper<T, st>::write(stream, v); + } + + template<class S> static inline void + read(S* stream, T& v) + { + assert((ot != OptionalTypeVSize && ot != OptionalTypeFSize && ot != OptionalTypeEndMarker) + || st == StreamTraitTypeBuiltin); + StreamHelper<T, st>::read(stream, v); + } +}; + // Helper to write fixed size structs template<typename T> struct StreamOptionalHelper<T, StreamTraitTypeStruct, OptionalTypeVSize> @@ -591,24 +598,8 @@ struct StreamOptionalHelper<T, StreamTraitTypeProxy, OptionalTypeFSize> : // // Helpers to read/write optional sequences or dictionaries // - -template<typename T, bool isVariableLength, int sz> -struct StreamOptionalContainerHelper -{ - static const OptionalType optionalType = OptionalTypeFSize; - - template<class S> static inline void - write(S* stream, const T& v, Ice::Int n) - { - assert(false); - } - - template<class S> static inline void - read(S* stream, T& v) - { - assert(false); - } -}; +template<typename T, bool isFixedLength, int sz> +struct StreamOptionalContainerHelper; // // Encode containers of variable size elements with the FSize optional @@ -617,7 +608,7 @@ struct StreamOptionalContainerHelper // so we just re-use its implementation. // template<typename T, int sz> -struct StreamOptionalContainerHelper<T, true, sz> +struct StreamOptionalContainerHelper<T, false, sz> { static const OptionalType optionalType = OptionalTypeFSize; @@ -640,7 +631,7 @@ struct StreamOptionalContainerHelper<T, true, sz> // encoding. // template<typename T, int sz> -struct StreamOptionalContainerHelper<T, false, sz> +struct StreamOptionalContainerHelper<T, true, sz> { static const OptionalType optionalType = OptionalTypeVSize; @@ -671,7 +662,7 @@ struct StreamOptionalContainerHelper<T, false, sz> // skip the optional. // template<typename T> -struct StreamOptionalContainerHelper<T, false, 1> +struct StreamOptionalContainerHelper<T, true, 1> { static const OptionalType optionalType = OptionalTypeVSize; @@ -697,22 +688,22 @@ struct StreamOptionalHelper<T, StreamTraitTypeSequence, ot> { typedef typename T::value_type E; static const int size = StreamTrait<E>::minWireSize; - static const bool isVariableLength = StreamTrait<E>::isVariableLength; + static const bool isFixedLength = IsFixedLength<E>::value; - // The optional type of a sequence depends on wether or not elements are fixed + // The optional type of a sequence depends on whether or not elements are fixed // or variable size elements and their size. - static const OptionalType optionalType = StreamOptionalContainerHelper<T, isVariableLength, size>::optionalType; + static const OptionalType optionalType = StreamOptionalContainerHelper<T, isFixedLength, size>::optionalType; template<class S> static inline void write(S* stream, const T& v) { - StreamOptionalContainerHelper<T, isVariableLength, size>::write(stream, v, v.size()); + StreamOptionalContainerHelper<T, isFixedLength, size>::write(stream, v, static_cast<Int>(v.size())); } template<class S> static inline void read(S* stream, T& v) { - StreamOptionalContainerHelper<T, isVariableLength, size>::read(stream, v); + StreamOptionalContainerHelper<T, isFixedLength, size>::read(stream, v); } }; @@ -721,23 +712,23 @@ struct StreamOptionalHelper<std::pair<const T*, const T*>, StreamTraitTypeSequen { typedef std::pair<const T*, const T*> P; static const int size = StreamTrait<T>::minWireSize; - static const bool isVariableLength = StreamTrait<T>::isVariableLength; + static const bool isFixedLength = IsFixedLength<T>::value; - // The optional type of a sequence depends on wether or not elements are fixed + // The optional type of a sequence depends on whether or not elements are fixed // or variable size elements and their size. - static const OptionalType optionalType = StreamOptionalContainerHelper<P, isVariableLength, size>::optionalType; + static const OptionalType optionalType = StreamOptionalContainerHelper<P, isFixedLength, size>::optionalType; template<class S> static inline void write(S* stream, const P& v) { Ice::Int n = static_cast<Ice::Int>(v.second - v.first); - StreamOptionalContainerHelper<P, isVariableLength, size>::write(stream, v, n); + StreamOptionalContainerHelper<P, isFixedLength, size>::write(stream, v, n); } template<class S> static inline void read(S* stream, P& v) { - StreamOptionalContainerHelper<P, isVariableLength, size>::read(stream, v); + StreamOptionalContainerHelper<P, isFixedLength, size>::read(stream, v); } }; @@ -746,23 +737,23 @@ struct StreamOptionalHelper<std::pair<T, T>, StreamTraitTypeSequence, ot> { typedef std::pair<T, T> P; static const int size = StreamTrait<typename T::value_type>::minWireSize; - static const bool isVariableLength = StreamTrait<typename T::value_type>::isVariableLength; + static const bool isFixedLength = IsFixedLength<typename T::value_type>::value; - // The optional type of a sequence depends on wether or not elements are fixed + // The optional type of a sequence depends on whether or not elements are fixed // or variable size elements and their size. - static const OptionalType optionalType = StreamOptionalContainerHelper<P, isVariableLength, size>::optionalType; + static const OptionalType optionalType = StreamOptionalContainerHelper<P, isFixedLength, size>::optionalType; template<class S> static inline void write(S* stream, const P& v) { Ice::Int n = static_cast<Ice::Int>(v.second - v.first); - StreamOptionalContainerHelper<P, isVariableLength, size>::write(stream, v, n); + StreamOptionalContainerHelper<P, isFixedLength, size>::write(stream, v, n); } template<class S> static inline void read(S* stream, P& v) { - StreamOptionalContainerHelper<P, isVariableLength, size>::read(stream, v); + StreamOptionalContainerHelper<P, isFixedLength, size>::read(stream, v); } }; @@ -772,25 +763,20 @@ struct StreamOptionalHelper<std::pair<IceUtil::ScopedArray<T>, std::pair<const T { typedef std::pair<IceUtil::ScopedArray<T>, std::pair<const T*, const T*> > P; static const int size = StreamTrait<T>::minWireSize; - static const bool isVariableLength = StreamTrait<T>::isVariableLength; + static const bool isFixedLength = IsFixedLength<T>::value; - // The optional type of a sequence depends on wether or not elements are fixed + // The optional type of a sequence depends on whether or not elements are fixed // or variable size elements and their size. - static const OptionalType optionalType = StreamOptionalContainerHelper<P, isVariableLength, size>::optionalType; - - template<class S> static inline void - write(S* stream, const P& v) - { - assert(false); - } + static const OptionalType optionalType = StreamOptionalContainerHelper<P, isFixedLength, size>::optionalType; template<class S> static inline void read(S* stream, P& v) { - StreamOptionalContainerHelper<P, isVariableLength, size>::read(stream, v); + StreamOptionalContainerHelper<P, isFixedLength, size>::read(stream, v); } -}; + // no write: only used for unmarshaling +}; // // Helper to write dictionaries, delegates to the optional container @@ -803,22 +789,22 @@ struct StreamOptionalHelper<T, StreamTraitTypeDictionary, ot> typedef typename T::mapped_type V; static const int size = StreamTrait<K>::minWireSize + StreamTrait<V>::minWireSize; - static const bool isVariableLength = StreamTrait<K>::isVariableLength || StreamTrait<V>::isVariableLength; + static const bool isFixedLength = IsFixedLength<K>::value && IsFixedLength<V>::value; - // The optional type of a dictionary depends on wether or not elements are fixed + // The optional type of a dictionary depends on whether or not elements are fixed // or variable size elements. - static const OptionalType optionalType = StreamOptionalContainerHelper<T, isVariableLength, size>::optionalType; + static const OptionalType optionalType = StreamOptionalContainerHelper<T, isFixedLength, size>::optionalType; template<class S> static inline void write(S* stream, const T& v) { - StreamOptionalContainerHelper<T, isVariableLength, size>::write(stream, v, v.size()); + StreamOptionalContainerHelper<T, isFixedLength, size>::write(stream, v, static_cast<Int>(v.size())); } template<class S> static inline void read(S* stream, T& v) { - StreamOptionalContainerHelper<T, isVariableLength, size>::read(stream, v); + StreamOptionalContainerHelper<T, isFixedLength, size>::read(stream, v); } }; |