1/* Marshalling and unmarshalling.
2   Copyright (C) 2014-2022 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along 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
28namespace 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
125