libcc1/marshall.hh

   1 /* Marshalling and unmarshalling.
   2    Copyright (C) 2014-2021 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef CC1_PLUGIN_MARSHALL_HH
  21 #define CC1_PLUGIN_MARSHALL_HH
  22
  23 #include <type_traits>
  24
  25 #include "status.hh"
  26 #include "gcc-interface.h"
  27
  28 namespace cc1_plugin
  29 {
  30   class connection;
  31
  32   // Only a single kind of integer is ever sent over the wire, and
  33   // this is it.
  34   typedef unsigned long long protocol_int;
  35
  36   // Read an integer from the connection and verify that it has the
  37   // value V.
  38   status unmarshall_check (connection *, protocol_int v);
  39
  40   // Write an integer, prefixed with the integer type marker, to the
  41   // connection.
  42   status marshall_intlike (connection *, protocol_int);
  43
  44   // Read a type marker from the connection and verify that it is an
  45   // integer type marker.  If not, return FAIL.  If so, read an
  46   // integer store it in the out argument.
  47   status unmarshall_intlike (connection *, protocol_int *);
  48
  49   status marshall_array_start (connection *, char, size_t);
  50   status marshall_array_elmts (connection *, size_t, void *);
  51
  52   status unmarshall_array_start (connection *, char, size_t *);
  53   status unmarshall_array_elmts (connection *, size_t, void *);
  54
  55   // An "empty" marshall call -- used to handle the base case for some
  56   // variadic templates.
  57   static inline
  58   status marshall (connection *)
  59   {
  60     return OK;
  61   }
  62
  63   // A template function that can handle marshalling various integer
  64   // objects to the connection.
  65   template<typename T>
  66   status marshall (connection *conn, T scalar)
  67   {
  68     return marshall_intlike (conn, scalar);
  69   }
  70
  71   // A template function that can handle unmarshalling various integer
  72   // objects from the connection.  Note that there's no way at the
  73   // protocol level to distinguish different int types.
  74   template<typename T>
  75   status unmarshall (connection *conn, T *scalar,
  76                      typename std::enable_if<std::is_integral<T>::value, T>::type * = 0)
  77   {
  78     protocol_int result;
  79
  80     if (!unmarshall_intlike (conn, &result))
  81       return FAIL;
  82     *scalar = (T) result;
  83     return OK;
  84   }
  85
  86   // A template function that can handle unmarshalling various enum
  87   // objects from the connection.
  88   template<typename T>
  89   status unmarshall (connection *conn, T *e_val,
  90                      typename std::enable_if<std::is_enum<T>::value, T>::type * = 0)
  91   {
  92     protocol_int result;
  93
  94     if (!unmarshall_intlike (conn, &result))
  95       return FAIL;
  96     *e_val = (T) result;
  97     return OK;
  98   }
  99
 100   // Send a string type marker followed by a string.
 101   status marshall (connection *, const char *);
 102
 103   // Read a string type marker followed by a string.  The caller is
 104   // responsible for freeing the resulting string using 'delete[]'.
 105   status unmarshall (connection *, char **);
 106
 107   // Send a gcc_type_array marker followed by the array.
 108   status marshall (connection *, const gcc_type_array *);
 109
 110   // Read a gcc_type_array marker, followed by a gcc_type_array.  The
 111   // resulting array must be freed by the caller, using 'delete[]' on
 112   // the elements, and 'delete' on the array object itself.
 113   status unmarshall (connection *, struct gcc_type_array **);
 114
 115   template<typename T1, typename T2, typename... Arg>
 116   status marshall (connection *c, T1 arg1, T2 arg2, Arg... rest)
 117   {
 118     if (!marshall (c, arg1))
 119       return FAIL;
 120     return marshall (c, arg2, rest...);
 121   }
 122 };
 123
 124 #endif // CC1_PLUGIN_MARSHALL_HH