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Diffstat (limited to 'TAO/tao/IIOP_Interpreter.h')
| -rw-r--r-- | TAO/tao/IIOP_Interpreter.h | 244 |
1 files changed, 0 insertions, 244 deletions
diff --git a/TAO/tao/IIOP_Interpreter.h b/TAO/tao/IIOP_Interpreter.h deleted file mode 100644 index eaefd86f6c1..00000000000 --- a/TAO/tao/IIOP_Interpreter.h +++ /dev/null @@ -1,244 +0,0 @@ -// This may look like C, but it's really -*- C++ -*- -// $Id$ - -// ============================================================================ -// -// = LIBRARY -// TAO -// -// = FILENAME -// IIOP_Interpreter.h -// -// = DESCRIPTION -// Header file for TAO's IIOP interpreter. -// -// = AUTHOR -// Douglas C. Schmidt -// -// ============================================================================ - -#if !defined (TAO_IIOP_INTERPRETER_H) -#define TAO_IIOP_INTERPRETER_H - -// Useful typedefs. -typedef size_t TAO_attribute_calculator (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Environment &env); -typedef CORBA::Boolean TAO_param_skip_rtn (TAO_InputCDR *); - -class TAO_Export TAO_IIOP_Interpreter -{ - // = TITLE - // TAO's CORBA TypeCode interpreter, which traverses GIOP/IIOP - // data structures. - // - // = DESCRIPTION - // This uses the standard C/C++ representation for data, and knows - // how to do things like align and pad according to standard - // rules. It is driven by CDR marshaled representations of - // TypeCodes. - // - // It does two key things: (a) calculate size and alignment - // restrictions for the data type described by any given typecode; - // and (b) "visits" each element of a data type in the order those - // elements are defined in the type's IDL definition. - // - // A typical use is that some application-specific "visit" - // function will be called with a typecode and data value. Then - // that "visit" function may choose to use the interpreter's - // knowledge of the environment's size, padding, and alignment - // rules to help it examine each of the constituents of complex - // data values. It does so by making a call to - // <TypeCode::traverse>, and passing itself for future recursive - // calls. - // - // NOTE that this module has system dependent parts, and so should - // be examined when porting to new CPU architectures, compilers, - // and so forth to make sure it correctly implements the - // appropriate binary interfaces. - // - // Issues of concern are primarily that sizes and representations - // of CORBA primitive data types are correct (key issues are - // verified when the ORB initializes) and that the alignment rules - // are recognized. - // - // Also, exceptions have vtables in them, which may cause trouble - // if they aren't located at the very beginning by the compiler in - // question. - // - // So for example, moving to another CPU architecture which still - // uses standard sized two's complement integers and IEEE floating - // point, and expects "natural" alignment, won't be hard. Even - // using PC style tightly packed data is simple; the alignment - // rules are just simpler. Most volume microprocessors used in - // 1995 are correctly supported. - // - // Using data representations that are far from the standard C/C++ - // style data layout is probably not practical with this - // implementation. LISP systems, as one example, probably won't - // use "in-memory" representations much like C/C++, even though - // its "wire form" could directly match CDR. - // - // ALSO, the treatment of exceptions may need to be examined in - // language environments which actually rely on C++ exceptions. - // The RTTI data that identifies exceptions can easily be ignored - // by this interpreter (if it's taught about that compiler's RTTI) - // but it may not be practical for any code not generated by that - // specific C++ compiler to store such data in the right place to - // look like a C++ exception, or to throw exceptions when that's - // needed. (RTTI == "Run Time Typing Information", needed to make - // C++ exceptions work correctly and partially exposed to users by - // the ANSI standards comittee. It provides type-safe - // "downcasting" and other features previously unavailable in - // C++.) - // - // THREADING NOTE: Data structures being traversed should only be - // modified by the thread doing the traversal. The interpretive - // code itself is reentrant (recursive!) so presents no threading - // issues; only the data being fed to the interpreter must be - // protected against concurrency. -public: - static void init_table (void); - // Initialize TAO's TypeCode table. - - static size_t calc_nested_size_and_alignment (CORBA::TypeCode_ptr tc, - TAO_InputCDR *original_stream, - size_t &alignment, - CORBA::Environment &env); - static size_t calc_nested_size_and_alignment_i (CORBA::TypeCode_ptr tc, - TAO_InputCDR *stream, - CORBA::TCKind kind, - size_t &alignment, - CORBA::Environment &env); - // For a given typecode, figure out its size and alignment needs. - // This version is used mostly when traversing other typecodes, and - // follows these rules: - // - // - Some typecodes are illegal (can't be nested inside others); - // - Indirections are allowed; - // - The whole typecode (including TCKind enum) is in the stream - // - // When the routine returns, the stream has skipped this TypeCode. - // - // "size" is returned, "alignment" is an 'out' parameter. If it is - // non-null, "tc" is initialized to hold the contents of the TypeCode; - // it depends on the contents of the original stream to be valid. - // - // The _i routine encapsulates some common code for the case were an - // indirected TypeCode is in use. - // - // @@ explore splitting apart returning the size/alignment data and - // the TypeCode initialization; union traversal would benefit a bit, - // but it would need more than that to make it as speedy as struct - // traversal. - - // = Static visitor methods. - - // These methods manipulate CDR-encapsulated TypeCode parameter - // lists, calculating the size and alignment of the data type being - // described. The TCKind value has always been removed from the CDR - // stream when these calculator routines get called. - - static size_t calc_struct_and_except_attributes (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Boolean is_exception, - CORBA::Environment &env); - // Given typecode bytes for a structure (or exception), figure out - // its alignment and size; return size, alignment is an 'out' - // parameter. Only "CORBA::tk_struct" (or "CORBA::tk_except") has - // been taken out of the stream parameter holding the bytes. - // - // We use a one-pass algorithm, calculating size and inter-element - // padding while recording the strongest alignment restriction. - // Then we correct the size to account for tail-padding. - // - // This routine recognizes that exceptions are just structs with - // some additional information. Different environments may differ - // in what that additional information is, so this routine may need - // to be taught about compiler-specific representation of that - // additional "RTTI" data. - - static size_t calc_struct_attributes (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Environment &env); - // Calculate size and alignment for a structure. - - - static size_t calc_exception_attributes (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Environment &env); - // Calculate size and alignment for an exception. - - - static size_t calc_union_attributes (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Environment &env); - // Calculate size and alignment for a CORBA discriminated union. - // - // Note that this is really a two-element structure. The first - // element is the discriminator; the second is the value. All normal - // structure padding/alignment rules apply. In particular, all arms - // of the union have the same initial address (adequately aligned for - // any of the members). - - - static size_t calc_alias_attributes (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Environment &env); - // Calculate size and alignment for a typedeffed type. - - static size_t calc_array_attributes (TAO_InputCDR *stream, - size_t &alignment, - CORBA::Environment &env); - // Calculate size and alignment of an array. (All such arrays are - // described as single dimensional, even though the IDL definition - // may specify a multidimensional array ... such arrays are treated - // as nested single dimensional arrays.) - - static CORBA::Boolean match_value (CORBA::TCKind kind, - TAO_InputCDR *tc_stream, - const void *value, - CORBA::Environment &env); - // Cast the discriminant values to the right type and compare them. - - static size_t - calc_key_union_attributes (TAO_InputCDR *stream, - size_t &overall_alignment, - size_t &discrim_size_with_pad, - CORBA::Environment &env); - - // = Utility routines that skip unneeded parameter lists. - static CORBA::Boolean skip_encapsulation (TAO_InputCDR *stream); - static CORBA::Boolean skip_long (TAO_InputCDR *stream); - - struct Table_Element - { - size_t size_; - size_t alignment_; - TAO_attribute_calculator *calc_; - TAO_param_skip_rtn *skipper_; - }; - - static Table_Element table_[CORBA::TC_KIND_COUNT]; - // Table supporting calculation of size and alignment requirements - // for any one instance of a given data types. - // - // This is indexed via CDR's TCKind values, which are "frozen" as - // part of the CDR standard. Entries hold either the size and - // alignment values for that data type, or a pointer to a function - // that is used to calculate those values. Function pointers are - // normally needed only for constructed types. - // - // A "skipper" routine is provided for some data types whose size is - // known statically (e.g. objrefs, structures, strings) but whose - // typecodes have parameters that sometimes need to be ignored when - // found in a CDR stream. Any attribute calculator routine always - // skips parameters in the CDR input stream, so no type with such a - // routine also needs a "skipper". - // - // Rather than growing a set of processor-specific #ifdefs, we - // calculate most of this table (except functions) at ORB - // initialization time. -}; - -#endif /* TAO_IIOP_INTERPRETER_H */ |