Re: RFC: add ability to "source" Python code

[Thiago Jung Bauermann <bauerman at br dot ibm dot com>]

Hi folks,

I'm resurrecting this old thread. I believe it is important that we
settle this discussion before 7.0.

Em Qui, 2009-02-19 Ãs 12:05 -0800, Joel Brobecker escreveu:
> > Eli> I'm okay with this, but I think Tom had some valid reasons for
> > Eli> having Python scripts that don't have a certain extension.
> > 
> > It is a convenience when using scratch files.
> > In practice I don't use -p much.  I don't mind removing it.
> 
> Ok, we can try without, and see if we get any request?

Agreed. I don't care much about -p either.

> So, where do you think we should go from now?
> a tri-state setting:
> 
>   1. Use filename extension and evaluate accordingly.
>      Error if the language was not compiled in.
> 
>   2, Use filename extension and evaluate accordingly.
>      Fallback to GDB scripting if the language was not compiled in.
> 
>   3. No filename extension recognition, always treat sourced files
>      as GDB scripts.
> 
> Would that be acceptable to everyone?

This patch implements such tri-state setting:

(gdb) help set script-extension
Set mode for script filename extension recognition.
off  == no filename extension recognition (all sourced files are GDB scripts)
soft == evaluate script according to filename extension, fallback to GDB script
hard == evaluate script according to filename extension, error if not supported

The default is 'soft'. When Python support is not compiled in, the code
always assumes a GDB script.

Is this good enough for everybody? Please ignore the documentation part
of the patch, I'll only update it when we have the code part ready to
commit.
-- 
[]'s
Thiago Jung Bauermann
IBM Linux Technology Center


2009-06-01  Tom Tromey  <tromey@redhat.com>
	    Thiago Jung Bauermann  <bauerman@br.ibm.com>

	* python/python.c (source_python_script): New function.
	* python/python.h (source_python_script): Declare.
	* cli/cli-cmds.c (find_argument): New function.
	(source_command): Use find_argument.  Handle -p argument.  Use
	make_cleanup_restore_integer.
	(source_verbose_cleanup): Remove.
	(source_python): New global.
	Include python.h.
	(init_cli_cmds): Update.

2009-06-01  Tom Tromey  <tromey@redhat.com>

	* gdb.texinfo (File Options): Document -x on .py files.
	(Command Files): Document source -p.

2009-06-01  Tom Tromey  <tromey@redhat.com>
	    Thiago Jung Bauermann  <bauerman@br.ibm.com>

	* gdb.base/help.exp: Update "source" help text.
	* gdb.python/source2.py: New file.
	* gdb.python/source1: New file.
	* gdb.python/python.exp: Test "source" command.

Index: gdb.git/gdb/cli/cli-cmds.c
===================================================================
--- gdb.git.orig/gdb/cli/cli-cmds.c	2009-06-01 00:51:11.000000000 -0300
+++ gdb.git/gdb/cli/cli-cmds.c	2009-06-01 00:52:37.000000000 -0300
@@ -19,6 +19,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include "exceptions.h"
 #include "readline/readline.h"
 #include "readline/tilde.h"
 #include "completer.h"
@@ -45,6 +46,8 @@
 #include "cli/cli-setshow.h"
 #include "cli/cli-cmds.h"
 
+#include "python/python.h"
+
 #ifdef TUI
 #include "tui/tui.h"		/* For tui_active et.al.   */
 #endif
@@ -181,6 +184,21 @@ struct cmd_list_element *showchecklist;
 int source_verbose = 0;
 int trace_commands = 0;
 
+/* 'script-extension' option support.  */
+
+static const char script_ext_off[] = "off";
+static const char script_ext_soft[] = "soft";
+static const char script_ext_hard[] = "hard";
+
+static const char *script_ext_enums[] = {
+  script_ext_off,
+  script_ext_soft,
+  script_ext_hard,
+  NULL
+};
+
+static const char *script_ext_mode = script_ext_soft;
+
 /* Utility used everywhere when at least one argument is needed and
    none is supplied. */
 
@@ -432,18 +450,25 @@ cd_command (char *dir, int from_tty)
     pwd_command ((char *) 0, 1);
 }
 
-void
-source_script (char *file, int from_tty)
+/* Show the current value of the 'script-extension' option.  */
+
+static void
+show_script_ext_mode (struct ui_file *file, int from_tty,
+		     struct cmd_list_element *c, const char *value)
 {
-  FILE *stream;
-  struct cleanup *old_cleanups;
+  fprintf_filtered (file, _("\
+Script filename extension recognition is \"%s\".\n"),
+		    value);
+}
+
+static int
+find_and_open_script (int from_tty, char **filep, FILE **streamp,
+		      struct cleanup **cleanupp)
+{
+  char *file = *filep;
   char *full_pathname = NULL;
   int fd;
-
-  if (file == NULL || *file == 0)
-    {
-      error (_("source command requires file name of file to source."));
-    }
+  struct cleanup *old_cleanups;
 
   file = tilde_expand (file);
   old_cleanups = make_cleanup (xfree, file);
@@ -467,12 +492,58 @@ source_script (char *file, int from_tty)
       else
 	{
 	  do_cleanups (old_cleanups);
-	  return;
+	  return 0;
 	}
     }
 
-  stream = fdopen (fd, FOPEN_RT);
-  script_from_file (stream, file);
+  *streamp = fdopen (fd, FOPEN_RT);
+  *filep = file;
+  *cleanupp = old_cleanups;
+
+  return 1;
+}
+
+void
+source_script (char *file, int from_tty)
+{
+  FILE *stream;
+  struct cleanup *old_cleanups;
+
+  if (file == NULL || *file == 0)
+    {
+      error (_("source command requires file name of file to source."));
+    }
+
+  if (!find_and_open_script (from_tty, &file, &stream, &old_cleanups))
+    return;
+
+  if (script_ext_mode != script_ext_off
+      && strlen (file) > 3 && !strcmp (&file[strlen (file) - 3], ".py"))
+    {
+      volatile struct gdb_exception e;
+
+      TRY_CATCH (e, RETURN_MASK_ERROR)
+	{
+	  source_python_script (stream, file);
+	}
+      if (e.reason < 0)
+	{
+	  /* Should we fallback to ye olde GDB script mode?  */
+	  if (script_ext_mode == script_ext_soft
+	      && e.reason == RETURN_ERROR && e.error == UNSUPPORTED_ERROR)
+	    {
+	      if (!find_and_open_script (from_tty, &file, &stream, &old_cleanups))
+		return;
+
+	      script_from_file (stream, file);
+	    }
+	  else
+	    /* Nope, just punt.  */
+	    throw_exception (e);
+	}
+    }
+  else
+    script_from_file (stream, file);
 
   do_cleanups (old_cleanups);
 }
@@ -1286,6 +1357,19 @@ when GDB is started."), gdbinit);
 	       source_help_text, &cmdlist);
   set_cmd_completer (c, filename_completer);
 
+  add_setshow_enum_cmd ("script-extension", class_support,
+			script_ext_enums, &script_ext_mode, _("\
+Set mode for script filename extension recognition."), _("\
+Show mode for script filename extension recognition."), _("\
+off  == no filename extension recognition (all sourced files are GDB scripts)\n\
+soft == evaluate script according to filename extension, fallback to GDB script"
+  "\n\
+hard == evaluate script according to filename extension, error if not supported"
+  ),
+			NULL,
+			show_script_ext_mode,
+			&setlist, &showlist);
+
   add_com ("quit", class_support, quit_command, _("Exit gdb."));
   c = add_com ("help", class_support, help_command,
 	       _("Print list of commands."));
Index: gdb.git/gdb/doc/gdb.texinfo
===================================================================
--- gdb.git.orig/gdb/doc/gdb.texinfo	2009-06-01 00:51:11.000000000 -0300
+++ gdb.git/gdb/doc/gdb.texinfo	2009-06-01 00:52:37.000000000 -0300
@@ -957,8 +957,11 @@ Connect to process ID @var{number}, as w
 @itemx -x @var{file}
 @cindex @code{--command}
 @cindex @code{-x}
-Execute @value{GDBN} commands from file @var{file}.  @xref{Command
-Files,, Command files}.
+Execute commands from file @var{file}.  If @var{file} ends in
+@samp{.py}, then the file is evaluated as Python code.  If Python
+support is not enabled in this @value{GDBN}, then the file is assumed to
+contain @value{GDBN} commands, regardless of its extension.
+@xref{Command Files,, Command files}.
 
 @item -eval-command @var{command}
 @itemx -ex @var{command}
@@ -18227,6 +18230,11 @@ If @code{-v}, for verbose mode, is given
 each command as it is executed.  The option must be given before
 @var{filename}, and is interpreted as part of the filename anywhere else.
 
+If @var{filename} ends in @samp{.py}, then @value{GDBN} evaluates the
+contents of the file as Python code.  If Python support is not compiled
+in to @value{GDBN}, then the file is assumed to contain @value{GDBN}
+commands, regardless of its extension.
+
 Commands that would ask for confirmation if used interactively proceed
 without asking when used in a command file.  Many @value{GDBN} commands that
 normally print messages to say what they are doing omit the messages
Index: gdb.git/gdb/python/python.c
===================================================================
--- gdb.git.orig/gdb/python/python.c	2009-06-01 00:51:11.000000000 -0300
+++ gdb.git/gdb/python/python.c	2009-06-01 00:52:37.000000000 -0300
@@ -18,6 +18,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include "exceptions.h"
 #include "command.h"
 #include "ui-out.h"
 #include "cli/cli-script.h"
@@ -275,6 +276,22 @@ execute_gdb_command (PyObject *self, PyO
   Py_RETURN_NONE;
 }
 
+/* Read a file as Python code.  STREAM is the input file; FILE is the
+   name of the file.  */
+
+void
+source_python_script (FILE *stream, char *file)
+{
+  PyGILState_STATE state;
+
+  state = PyGILState_Ensure ();
+
+  PyRun_SimpleFile (stream, file);
+
+  fclose (stream);
+  PyGILState_Release (state);
+}
+
 
 
 /* Printing.  */
@@ -460,6 +477,14 @@ eval_python_from_control_command (struct
   error (_("Python scripting is not supported in this copy of GDB."));
 }
 
+void
+source_python_script (FILE *stream, char *file)
+{
+  fclose (stream);
+  throw_error (UNSUPPORTED_ERROR,
+	       _("Python scripting is not supported in this copy of GDB."));
+}
+
 #endif /* HAVE_PYTHON */
 
 
Index: gdb.git/gdb/python/python.h
===================================================================
--- gdb.git.orig/gdb/python/python.h	2009-06-01 00:51:12.000000000 -0300
+++ gdb.git/gdb/python/python.h	2009-06-01 00:53:48.000000000 -0300
@@ -26,6 +26,8 @@ extern struct value *values_in_python;
 
 void eval_python_from_control_command (struct command_line *);
 
+void source_python_script (FILE *stream, char *file);
+
 int apply_val_pretty_printer (struct type *type, const gdb_byte *valaddr,
 			      int embedded_offset, CORE_ADDR address,
 			      struct ui_file *stream, int recurse,
Index: gdb.git/gdb/testsuite/gdb.python/python.exp
===================================================================
--- gdb.git.orig/gdb/testsuite/gdb.python/python.exp	2009-06-01 00:52:37.000000000 -0300
+++ gdb.git/gdb/testsuite/gdb.python/python.exp	2009-06-01 00:55:50.000000000 -0300
@@ -27,8 +27,8 @@ gdb_start
 gdb_reinitialize_dir $srcdir/$subdir
 
 if ![python_supported] then {
-  unsupported "python support is disabled"
-  return -1
+  gdb_test "source $srcdir/$subdir/source2.py" "Error in sourced command file:.*"
+  return 0
 }
 
 gdb_py_test_multiple "multi-line python command" \
@@ -51,5 +51,7 @@ gdb_py_test_multiple "indented multi-lin
   "foo ()" "" \
   "end" "hello, world!"
 
+gdb_test "source $srcdir/$subdir/source2.py" "yes"
+
 gdb_test "python print gdb.current_objfile()" "None"
 gdb_test "python print gdb.objfiles()" "\\\[\\\]"
Index: gdb.git/gdb/testsuite/gdb.python/source1
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb.git/gdb/testsuite/gdb.python/source1	2009-06-01 00:52:37.000000000 -0300
@@ -0,0 +1,19 @@
+#  This testcase is part of GDB, the GNU debugger.
+
+#  Copyright 2008, 2009 Free Software Foundation, Inc.
+
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 3 of the License, or
+#  (at your option) any later version.
+
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+
+#  You should have received a copy of the GNU General Public License
+#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This is sourced as python; pick an expression that is not valid for gdb.
+print 'y%ss' % 'e'
Index: gdb.git/gdb/testsuite/gdb.python/source2.py
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb.git/gdb/testsuite/gdb.python/source2.py	2009-06-01 00:52:37.000000000 -0300
@@ -0,0 +1,18 @@
+#  This testcase is part of GDB, the GNU debugger.
+
+#  Copyright 2008, 2009 Free Software Foundation, Inc.
+
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 3 of the License, or
+#  (at your option) any later version.
+
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+
+#  You should have received a copy of the GNU General Public License
+#  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+print 'y%ss' % 'e'
Index: gdb.git/gdb/exceptions.h
===================================================================
--- gdb.git.orig/gdb/exceptions.h	2009-06-01 00:51:12.000000000 -0300
+++ gdb.git/gdb/exceptions.h	2009-06-01 00:52:37.000000000 -0300
@@ -75,6 +75,9 @@ enum errors {
   /* Error accessing memory.  */
   MEMORY_ERROR,
 
+  /* Feature is not supported in this copy of GDB.  */
+  UNSUPPORTED_ERROR,
+
   /* Add more errors here.  */
   NR_ERRORS
 };