lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp

   1 #include "PythonReadline.h"
   2
   3 #ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE
   4
   5 #include <cstdio>
   6
   7 #include <editline/readline.h>
   8
   9 // Simple implementation of the Python readline module using libedit.
  10 // In the event that libedit is excluded from the build, this turns
  11 // back into a null implementation that blocks the module from pulling
  12 // in the GNU readline shared lib, which causes linkage confusion when
  13 // both readline and libedit's readline compatibility symbols collide.
  14 //
  15 // Currently it only installs a PyOS_ReadlineFunctionPointer, without
  16 // implementing any of the readline module methods. This is meant to
  17 // work around LLVM pr18841 to avoid seg faults in the stock Python
  18 // readline.so linked against GNU readline.
  19 //
  20 // Bug on the cpython side: https://bugs.python.org/issue38634
  21
  22 PyDoc_STRVAR(moduleDocumentation,
  23              "Simple readline module implementation based on libedit.");
  24
  25 static struct PyModuleDef readline_module = {
  26     PyModuleDef_HEAD_INIT, // m_base
  27     "lldb_editline",       // m_name
  28     moduleDocumentation,   // m_doc
  29     -1,                    // m_size
  30     nullptr,               // m_methods
  31     nullptr,               // m_reload
  32     nullptr,               // m_traverse
  33     nullptr,               // m_clear
  34     nullptr,               // m_free
  35 };
  36
  37 static char *simple_readline(FILE *stdin, FILE *stdout, const char *prompt) {
  38   rl_instream = stdin;
  39   rl_outstream = stdout;
  40   char *line = readline(prompt);
  41   if (!line) {
  42     char *ret = (char *)PyMem_RawMalloc(1);
  43     if (ret != nullptr)
  44       *ret = '\0';
  45     return ret;
  46   }
  47   if (*line)
  48     add_history(line);
  49   int n = strlen(line);
  50   char *ret = (char *)PyMem_RawMalloc(n + 2);
  51   if (ret) {
  52     memcpy(ret, line, n);
  53     free(line);
  54     ret[n] = '\n';
  55     ret[n + 1] = '\0';
  56   }
  57   return ret;
  58 }
  59
  60 PyMODINIT_FUNC initlldb_readline(void) {
  61   PyOS_ReadlineFunctionPointer = simple_readline;
  62
  63   return PyModule_Create(&readline_module);
  64 }
  65 #endif