gdb/guile/scm-string.c

   1 /* GDB/Scheme charset interface.
   2
   3    Copyright (C) 2014-2021 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 /* See README file in this directory for implementation notes, coding
  21    conventions, et.al.  */
  22
  23 #include "defs.h"
  24 #include "charset.h"
  25 #include "guile-internal.h"
  26
  27 /* Convert STRING to an int.
  28    STRING must be a valid integer.  */
  29
  30 int
  31 gdbscm_scm_string_to_int (SCM string)
  32 {
  33   char *s = scm_to_latin1_string (string);
  34   int r = atoi (s);
  35
  36   free (s);
  37   return r;
  38 }
  39
  40 /* Convert a C (latin1) string to an SCM string.
  41    "latin1" is chosen because Guile won't throw an exception.  */
  42
  43 SCM
  44 gdbscm_scm_from_c_string (const char *string)
  45 {
  46   return scm_from_latin1_string (string);
  47 }
  48
  49 /* Convert an SCM string to a C (latin1) string.
  50    "latin1" is chosen because Guile won't throw an exception.
  51    It is an error to call this if STRING is not a string.  */
  52
  53 gdb::unique_xmalloc_ptr<char>
  54 gdbscm_scm_to_c_string (SCM string)
  55 {
  56   return gdb::unique_xmalloc_ptr<char> (scm_to_latin1_string (string));
  57 }
  58
  59 /* Use printf to construct a Scheme string.  */
  60
  61 SCM
  62 gdbscm_scm_from_printf (const char *format, ...)
  63 {
  64   va_list args;
  65   SCM result;
  66
  67   va_start (args, format);
  68   std::string string = string_vprintf (format, args);
  69   va_end (args);
  70   result = scm_from_latin1_string (string.c_str ());
  71
  72   return result;
  73 }
  74
  75 /* Struct to pass data from gdbscm_scm_to_string to
  76    gdbscm_call_scm_to_stringn.  */
  77
  78 struct scm_to_stringn_data
  79 {
  80   SCM string;
  81   size_t *lenp;
  82   const char *charset;
  83   scm_t_string_failed_conversion_handler conversion_kind;
  84   char *result;
  85 };
  86
  87 /* Helper for gdbscm_scm_to_string to call scm_to_stringn
  88    from within scm_c_catch.  */
  89
  90 static SCM
  91 gdbscm_call_scm_to_stringn (void *datap)
  92 {
  93   struct scm_to_stringn_data *data = (struct scm_to_stringn_data *) datap;
  94
  95   data->result = scm_to_stringn (data->string, data->lenp, data->charset,
  96                                  data->conversion_kind);
  97   return SCM_BOOL_F;
  98 }
  99
 100 /* Convert an SCM string to a string in charset CHARSET.
 101    This function is guaranteed to not throw an exception.
 102
 103    If LENP is NULL then the returned string is NUL-terminated,
 104    and an exception is thrown if the string contains embedded NULs.
 105    Otherwise the string is not guaranteed to be NUL-terminated, but worse
 106    there's no space to put a NUL if we wanted to (scm_to_stringn limitation).
 107
 108    If STRICT is non-zero, and there's a conversion error, then a
 109    <gdb:exception> object is stored in *EXCEPT_SCMP, and NULL is returned.
 110    If STRICT is zero, then escape sequences are used for characters that
 111    can't be converted, and EXCEPT_SCMP may be passed as NULL.
 112
 113    It is an error to call this if STRING is not a string.  */
 114
 115 gdb::unique_xmalloc_ptr<char>
 116 gdbscm_scm_to_string (SCM string, size_t *lenp,
 117                       const char *charset, int strict, SCM *except_scmp)
 118 {
 119   struct scm_to_stringn_data data;
 120   SCM scm_result;
 121
 122   data.string = string;
 123   data.lenp = lenp;
 124   data.charset = charset;
 125   data.conversion_kind = (strict
 126                           ? SCM_FAILED_CONVERSION_ERROR
 127                           : SCM_FAILED_CONVERSION_ESCAPE_SEQUENCE);
 128   data.result = NULL;
 129
 130   scm_result = gdbscm_call_guile (gdbscm_call_scm_to_stringn, &data, NULL);
 131
 132   if (gdbscm_is_false (scm_result))
 133     {
 134       gdb_assert (data.result != NULL);
 135       return gdb::unique_xmalloc_ptr<char> (data.result);
 136     }
 137   gdb_assert (gdbscm_is_exception (scm_result));
 138   *except_scmp = scm_result;
 139   return NULL;
 140 }
 141
 142 /* Struct to pass data from gdbscm_scm_from_string to
 143    gdbscm_call_scm_from_stringn.  */
 144
 145 struct scm_from_stringn_data
 146 {
 147   const char *string;
 148   size_t len;
 149   const char *charset;
 150   scm_t_string_failed_conversion_handler conversion_kind;
 151   SCM result;
 152 };
 153
 154 /* Helper for gdbscm_scm_from_string to call scm_from_stringn
 155    from within scm_c_catch.  */
 156
 157 static SCM
 158 gdbscm_call_scm_from_stringn (void *datap)
 159 {
 160   struct scm_from_stringn_data *data = (struct scm_from_stringn_data *) datap;
 161
 162   data->result = scm_from_stringn (data->string, data->len, data->charset,
 163                                    data->conversion_kind);
 164   return SCM_BOOL_F;
 165 }
 166
 167 /* Convert STRING to a Scheme string in charset CHARSET.
 168    This function is guaranteed to not throw an exception.
 169
 170    If STRICT is non-zero, and there's a conversion error, then a
 171    <gdb:exception> object is returned.
 172    If STRICT is zero, then question marks are used for characters that
 173    can't be converted (limitation of underlying Guile conversion support).  */
 174
 175 SCM
 176 gdbscm_scm_from_string (const char *string, size_t len,
 177                         const char *charset, int strict)
 178 {
 179   struct scm_from_stringn_data data;
 180   SCM scm_result;
 181
 182   data.string = string;
 183   data.len = len;
 184   data.charset = charset;
 185   /* The use of SCM_FAILED_CONVERSION_QUESTION_MARK is specified by Guile.  */
 186   data.conversion_kind = (strict
 187                           ? SCM_FAILED_CONVERSION_ERROR
 188                           : SCM_FAILED_CONVERSION_QUESTION_MARK);
 189   data.result = SCM_UNDEFINED;
 190
 191   scm_result = gdbscm_call_guile (gdbscm_call_scm_from_stringn, &data, NULL);
 192
 193   if (gdbscm_is_false (scm_result))
 194     {
 195       gdb_assert (!SCM_UNBNDP (data.result));
 196       return data.result;
 197     }
 198   gdb_assert (gdbscm_is_exception (scm_result));
 199   return scm_result;
 200 }
 201
 202 /* Convert an SCM string to a host string.
 203    This function is guaranteed to not throw an exception.
 204
 205    If LENP is NULL then the returned string is NUL-terminated,
 206    and if the string contains embedded NULs then NULL is returned with
 207    an exception object stored in *EXCEPT_SCMP.
 208    Otherwise the string is not guaranteed to be NUL-terminated, but worse
 209    there's no space to put a NUL if we wanted to (scm_to_stringn limitation).
 210
 211    Returns NULL if there is a conversion error, with the exception object
 212    stored in *EXCEPT_SCMP.
 213    It is an error to call this if STRING is not a string.  */
 214
 215 gdb::unique_xmalloc_ptr<char>
 216 gdbscm_scm_to_host_string (SCM string, size_t *lenp, SCM *except_scmp)
 217 {
 218   return gdbscm_scm_to_string (string, lenp, host_charset (), 1, except_scmp);
 219 }
 220
 221 /* Convert a host string to an SCM string.
 222    This function is guaranteed to not throw an exception.
 223    Returns a <gdb:exception> object if there's a conversion error.  */
 224
 225 SCM
 226 gdbscm_scm_from_host_string (const char *string, size_t len)
 227 {
 228   return gdbscm_scm_from_string (string, len, host_charset (), 1);
 229 }
 230
 231 /* (string->argv string) -> list
 232    Return list of strings split up according to GDB's argv parsing rules.
 233    This is useful when writing GDB commands in Scheme.  */
 234
 235 static SCM
 236 gdbscm_string_to_argv (SCM string_scm)
 237 {
 238   char *string;
 239   SCM result = SCM_EOL;
 240
 241   gdbscm_parse_function_args (FUNC_NAME, SCM_ARG1, NULL, "s",
 242                               string_scm, &string);
 243
 244   if (string == NULL || *string == '\0')
 245     {
 246       xfree (string);
 247       return SCM_EOL;
 248     }
 249
 250   gdb_argv c_argv (string);
 251   for (char *arg : c_argv)
 252     result = scm_cons (gdbscm_scm_from_c_string (arg), result);
 253
 254   xfree (string);
 255
 256   return scm_reverse_x (result, SCM_EOL);
 257 }
 258 \f
 259 /* Initialize the Scheme charset interface to GDB.  */
 260
 261 static const scheme_function string_functions[] =
 262 {
 263   { "string->argv", 1, 0, 0, as_a_scm_t_subr (gdbscm_string_to_argv),
 264   "\
 265 Convert a string to a list of strings split up according to\n\
 266 gdb's argv parsing rules." },
 267
 268   END_FUNCTIONS
 269 };
 270
 271 void
 272 gdbscm_initialize_strings (void)
 273 {
 274   gdbscm_define_functions (string_functions, 1);
 275 }