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

[Joel Brobecker <brobecker at adacore dot com>]

Hello,

Attached is the patch that I ended up checking in.  I'll propose a NEWS
entry momentarily.

-- 
Joel

commit 6a67114416d55f906d0b5aa05e11c3cfaa5b7adf
Author: Joel Brobecker <brobecker@adacore.com>
Date:   Mon Jan 18 09:54:28 2010 +0400

    Allow "source" to load python scripts.
    
    gdb/ChangeLog:
    
            Tom Tromey  <tromey@redhat.com>
            Thiago Jung Bauermann  <bauerman@br.ibm.com>
            * exceptions.h (enum errors): Add UNSUPPORTED_ERROR.
            * python/python.c (source_python_script): New function.
            * python/python.h (source_python_script): Add declaration.
            * cli/cli-cmds.c: #include exceptions.h and python/python.h.
            (script_ext_off, script_ext_soft, script_ext_strict)
            (script_ext_enums, script_ext_mode): New static constants.
            (show_script_ext_mode, find_and_open_script): New functions.
            (source_script): Enhance to handle Python scripts.
            (init_cli_cmds): Add set/show script-extension commands.
    
    gdb/doc/ChangeLog:
    
            Tom Tromey  <tromey@redhat.com>
            * gdb.texinfo (File Options): Document -x on .py files.
            (Command Files): Document handling of Python scripts.
    
    gdb/testsuite/ChangeLog:
    
            Tom Tromey  <tromey@redhat.com>
            Thiago Jung Bauermann  <bauerman@br.ibm.com>
            * gdb.python/source2.py: New file.
            * gdb.python/source1: New file.
            * gdb.python/python.exp: Test "source" command.

diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 4833898..7400967 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -19,6 +19,7 @@
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include "defs.h"
+#include "exceptions.h"
 #include "arch-utils.h"
 #include "readline/readline.h"
 #include "readline/tilde.h"
@@ -47,6 +48,8 @@ extern void disconnect_or_stop_tracing (int from_tty);
 #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
@@ -187,6 +190,21 @@ 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_strict[] = "strict";
+
+static const char *script_ext_enums[] = {
+  script_ext_off,
+  script_ext_soft,
+  script_ext_strict,
+  NULL
+};
+
+static const char *script_ext_mode = script_ext_soft;
+
 /* Utility used everywhere when at least one argument is needed and
    none is supplied. */
 
@@ -441,18 +459,25 @@ 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);
@@ -476,12 +501,58 @@ 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);
 }
@@ -1314,6 +1385,19 @@ 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\
+strict == 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."));
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 7cf1bb4..d37712b 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -963,8 +963,11 @@ Connect to process ID @var{number}, as with the @code{attach} command.
 @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}
@@ -19159,6 +19162,11 @@ If @code{-v}, for verbose mode, is given then @value{GDBN} displays
 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
diff --git a/gdb/exceptions.h b/gdb/exceptions.h
index 84a9f01..6b3cbeb 100644
--- a/gdb/exceptions.h
+++ b/gdb/exceptions.h
@@ -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
 };
diff --git a/gdb/python/python.c b/gdb/python/python.c
index 827372c..1f1ae72 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -343,6 +343,22 @@ gdbpy_parse_and_eval (PyObject *self, PyObject *args)
   return value_to_value_object (result);
 }
 
+/* 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.  */
@@ -525,6 +541,14 @@ eval_python_from_control_command (struct command_line *cmd)
   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 */
 
 
diff --git a/gdb/python/python.h b/gdb/python/python.h
index f35827b..5d93f67 100644
--- a/gdb/python/python.h
+++ b/gdb/python/python.h
@@ -24,6 +24,8 @@
 
 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,
diff --git a/gdb/testsuite/gdb.python/python.exp b/gdb/testsuite/gdb.python/python.exp
index 951c295..b345ad2 100644
--- a/gdb/testsuite/gdb.python/python.exp
+++ b/gdb/testsuite/gdb.python/python.exp
@@ -29,6 +29,10 @@ gdb_reinitialize_dir $srcdir/$subdir
 gdb_test_multiple "python print 23" "verify python support" {
     -re "not supported.*$gdb_prompt $"	{
       unsupported "python support is disabled"
+
+      # If Python is not supported, verify that sourcing a python script
+      # causes an error.
+      gdb_test "source $srcdir/$subdir/source2.py" "Error in sourced command file:.*"
       return -1
     }
     -re "$gdb_prompt $"	{}
@@ -72,5 +76,7 @@ gdb_py_test_multiple "indented multi-line python command" \
   "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()" "\\\[\\\]"
diff --git a/gdb/testsuite/gdb.python/source1 b/gdb/testsuite/gdb.python/source1
new file mode 100644
index 0000000..f9c19bd
--- /dev/null
+++ b/gdb/testsuite/gdb.python/source1
@@ -0,0 +1,19 @@
+#  This testcase is part of GDB, the GNU debugger.
+
+#  Copyright 2008, 2009, 2010 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'
diff --git a/gdb/testsuite/gdb.python/source2.py b/gdb/testsuite/gdb.python/source2.py
new file mode 100644
index 0000000..4e9a9e3
--- /dev/null
+++ b/gdb/testsuite/gdb.python/source2.py
@@ -0,0 +1,18 @@
+#  This testcase is part of GDB, the GNU debugger.
+
+#  Copyright 2008, 2009, 2010 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'