src/gromacs/selection/parser_internal.h

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  36 /*! \internal \file
  37  * \brief Helper functions for the selection parser.
  38  *
  39  * This header is includes only from parser.cpp (generated from parser.y), and
  40  * it includes functions and macros used internally by the parser.
  41  * They are in a separate file to make then easier to edit (no need to
  42  * regenerate the parser), and to keep parser.y as simple as possible.
  43  *
  44  * \author Teemu Murtola <teemu.murtola@gmail.com>
  45  * \ingroup module_selection
  46  */
  47 #ifndef GMX_SELECTION_PARSER_INTERNAL_H
  48 #define GMX_SELECTION_PARSER_INTERNAL_H
  49
  50 #include <exception>
  51 #include <memory>
  52
  53 #include "gromacs/utility/exceptions.h"
  54 #include "gromacs/utility/gmxassert.h"
  55 #include "gromacs/utility/stringutil.h"
  56
  57 #include "parsetree.h"
  58 #include "scanner.h"
  59 #include "selelem.h"
  60
  61 //! Error handler needed by Bison.
  62 static void yyerror(YYLTYPE* location, yyscan_t scanner, char const* s)
  63 {
  64     try
  65     {
  66         std::string            context(_gmx_sel_lexer_get_text(scanner, *location));
  67         gmx::InvalidInputError ex(s);
  68         // TODO: Examine how to show better context information.
  69         if (!context.empty())
  70         {
  71             context = gmx::formatString("Near '%s'", context.c_str());
  72             ex.prependContext(context);
  73         }
  74         _gmx_sel_lexer_set_exception(scanner, std::make_exception_ptr(ex));
  75     }
  76     catch (const std::exception&)
  77     {
  78         _gmx_sel_lexer_set_exception(scanner, std::current_exception());
  79     }
  80 }
  81
  82 //! Logic for computing the location of the output of Bison reduction.
  83 #define YYLLOC_DEFAULT(Current, Rhs, N)                                            \
  84     do                                                                             \
  85     {                                                                              \
  86         if ((N) != 0)                                                              \
  87         {                                                                          \
  88             (Current).startIndex = YYRHSLOC(Rhs, 1).startIndex;                    \
  89             (Current).endIndex   = YYRHSLOC(Rhs, N).endIndex;                      \
  90         }                                                                          \
  91         else                                                                       \
  92         {                                                                          \
  93             (Current).startIndex = (Current).endIndex = YYRHSLOC(Rhs, 0).endIndex; \
  94         }                                                                          \
  95         _gmx_sel_lexer_set_current_location(scanner, (Current));                   \
  96     } while (0)
  97
  98 /*! \brief
  99  * Custom macro to influence Bison behavior.
 100  *
 101  * This macro added to parser.cpp through our patch to force Bison to
 102  * use C-style logic for stack reallocation even though we have provided
 103  * YYLTYPE and are compiling the code in C++ (our YYLTYPE can safely be copied
 104  * this way).
 105  * An alternative would be to provide the whole reallocation logic through an
 106  * undocumented yyoverflow() macro, but that is probably also more trouble than
 107  * it is worth.
 108  */
 109 #define GMX_YYFORCE_C_STACK_EXTENSION 1
 110
 111 /*! \name Exception handling macros for actions
 112  *
 113  * These macros should be used at the beginning and end of each semantic action
 114  * that may throw an exception. For robustness, it's best to wrap all actions
 115  * that call functions declared outside parser.y should be wrapped.
 116  * These macros take care to catch any exceptions, store the exception (or
 117  * handle it and allow the parser to continue), and terminate the parser
 118  * cleanly if necessary.
 119  * The code calling the parser should use
 120  * _gmx_sel_lexer_rethrow_exception_if_occurred() to rethrow any exceptions.
 121  * \{
 122  */
 123 //! Starts an action that may throw exceptions.
 124 #define BEGIN_ACTION \
 125     try              \
 126     {
 127 //! Finishes an action that may throw exceptions.
 128 #define END_ACTION                                         \
 129     }                                                      \
 130     catch (std::exception & ex)                            \
 131     {                                                      \
 132         if (_gmx_selparser_handle_exception(scanner, &ex)) \
 133         {                                                  \
 134             YYERROR;                                       \
 135         }                                                  \
 136         else                                               \
 137         {                                                  \
 138             YYABORT;                                       \
 139         }                                                  \
 140     }
 141 //! Finishes an action that may throw exceptions and does not support resuming.
 142 #define END_ACTION_TOPLEVEL                                              \
 143     }                                                                    \
 144     catch (const std::exception&)                                        \
 145     {                                                                    \
 146         _gmx_sel_lexer_set_exception(scanner, std::current_exception()); \
 147         YYABORT;                                                         \
 148     }
 149 //!\}
 150
 151 /*! \brief
 152  * Retrieves a semantic value.
 153  *
 154  * \param[in] src  Semantic value to get the value from.
 155  * \returns   Retrieved value.
 156  * \throws    unspecified  Any exception thrown by the move constructor of
 157  *      ValueType.
 158  *
 159  * There should be no statements that may throw exceptions in actions before
 160  * this function has been called for all semantic values that have a C++ object
 161  * stored.  Together with set(), this function abstracts away exception
 162  * safety issues that arise from the use of a plain pointer for storing the
 163  * semantic values.
 164  *
 165  * Does not throw for smart pointer types.  If used with types that may throw,
 166  * the order of operations should be such that it is exception-safe.
 167  */
 168 template<typename ValueType>
 169 static ValueType get(ValueType* src)
 170 {
 171     GMX_RELEASE_ASSERT(src != nullptr, "Semantic value pointers should be non-NULL");
 172     const std::unique_ptr<ValueType> srcGuard(src);
 173     return ValueType(std::move(*src));
 174 }
 175 /*! \brief
 176  * Sets a semantic value.
 177  *
 178  * \tparam     ValueType Type of value to set.
 179  * \param[out] dest  Semantic value to set (typically $$).
 180  * \param[in]  value Value to put into the semantic value.
 181  * \throws     std::bad_alloc if out of memory.
 182  * \throws     unspecified  Any exception thrown by the move constructor of
 183  *      ValueType.
 184  *
 185  * This should be the last statement before ::END_ACTION, except for a
 186  * possible ::CHECK_SEL.
 187  */
 188 template<typename ValueType>
 189 static void set(ValueType*& dest, ValueType value)
 190 {
 191     dest = new ValueType(std::move(value));
 192 }
 193 /*! \brief
 194  * Sets an empty semantic value.
 195  *
 196  * \tparam     ValueType Type of value to set (must be default constructible).
 197  * \param[out] dest  Semantic value to set (typically $$).
 198  * \throws     std::bad_alloc if out of memory.
 199  * \throws     unspecified  Any exception thrown by the default constructor of
 200  *      ValueType.
 201  *
 202  * This should be the last statement before ::END_ACTION, except for a
 203  * possible ::CHECK_SEL.
 204  */
 205 template<typename ValueType>
 206 static void set_empty(ValueType*& dest)
 207 {
 208     dest = new ValueType;
 209 }
 210 /*! \brief
 211  * Checks that a valid tree was set.
 212  *
 213  * Should be called after set() if it was used to set a value where NULL
 214  * pointer indicates an error.
 215  *
 216  * \todo
 217  * Get rid of this macro.  It should now be possible to handle all errors using
 218  * exceptions.
 219  */
 220 #define CHECK_SEL(sel) \
 221     if (!*(sel))       \
 222     {                  \
 223         delete (sel);  \
 224         YYERROR;       \
 225     }
 226
 227 #endif