[RFA v2 7/8] Allow breakpoint commands to be set from Python

[Phil Muldoon]

>  
>  @node Finish Breakpoints in Python
> diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
> index d654b92a8c..a66e553cf8 100644
> --- a/gdb/python/py-breakpoint.c
> +++ b/gdb/python/py-breakpoint.c
> @@ -510,6 +510,49 @@ bppy_get_commands (PyObject *self, void *closure)
>    return host_string_to_python_string (stb.c_str ());
>  }
>  
> +/* Set the commands attached to a breakpoint.  Returns 0 on success.
> +   Returns -1 on error, with a python exception set.  */
> +static int
> +bppy_set_commands (PyObject *self, PyObject *newvalue, void *closure)
> +{
> +  gdbpy_breakpoint_object *self_bp = (gdbpy_breakpoint_object *) self;
> +  struct breakpoint *bp = self_bp->bp;
> +  struct gdb_exception except = exception_none;
> +
> +  BPPY_SET_REQUIRE_VALID (self_bp);
> +
> +  gdb::unique_xmalloc_ptr<char> commands
> +    (python_string_to_host_string (newvalue));
> +  if (commands == nullptr)
> +    return -1;
> +
> +  TRY
> +    {
> +      bool first = true;
> +      char *save_ptr = nullptr;
> +      auto reader
> +	= [&] ()
> +	  {
> +	    const char *result = strtok_r (first ? commands.get () : nullptr,
> +					   "\n", &save_ptr);
> +	    first = false;
> +	    return result;
> +	  };
> +
> +      counted_command_line lines = read_command_lines_1 (reader, 1, nullptr);
> +      breakpoint_set_commands (self_bp->bp, std::move (lines));
> +    }
> +  CATCH (ex, RETURN_MASK_ALL)
> +    {
> +      except = ex;
> +    }
> +  END_CATCH
> +
> +  GDB_PY_SET_HANDLE_EXCEPTION (except);
> +
> +  return 0;
> +}

The code bits LGTM but on a somewhat side note I'm wondering if there
are any side effects with the Python breakpoint stop callback? This
shouldn't interfere with the viability of this patch, though, because
a breakpoint previously could have had a command list attached to it
after being created in Python and via the commands command. I'm mildly
curious what would get called first.

Cheers

Phil