RFC: add ability to "source" Python code

[Tom Tromey <elpa@tromey.com>]

This patch adds Python support to the gdb "source" command.
I added this after several user questions about how to do this.
Also, due to completion, it is much more convenient than the
equivalent "python" command.

With this patch, a file ending in ".py" is automatically treated as
Python.  Also, other files can be interpreted as Python code by using
the "-p" switch.  I made other switches into errors, on the theory
that maybe we'd want to take more later ... I'm not sure if this is a
good idea or not.

This patch also changes '-x' to accept .py files, as a side effect.

This could use a documentation review.  Also I'd appreciate any
comments on it; it does change "source" incompatibly, though in a way
that is very unlikely to affect users.

Built and regression tested on x86-64 (compile farm).
New test case included.

Tom

2009-02-07  Tom Tromey  <tromey@redhat.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.

2009-02-07  Tom Tromey  <tromey@redhat.com>

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

2009-02-07  Tom Tromey  <tromey@redhat.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.

diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
index 4d9c4f3..3713927 100644
--- a/gdb/cli/cli-cmds.c
+++ b/gdb/cli/cli-cmds.c
@@ -45,6 +45,8 @@
 #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
@@ -178,6 +180,7 @@ struct cmd_list_element *showchecklist;
 
 /* Command tracing state.  */
 
+static int source_python = 0;
 int source_verbose = 0;
 int trace_commands = 0;
 \f
@@ -439,6 +442,7 @@ source_script (char *file, int from_tty)
   struct cleanup *old_cleanups;
   char *full_pathname = NULL;
   int fd;
+  int is_python;
 
   if (file == NULL || *file == 0)
     {
@@ -471,30 +475,44 @@ source_script (char *file, int from_tty)
 	}
     }
 
+  is_python = source_python;
+  if (strlen (file) > 3 && !strcmp (&file[strlen (file) - 3], ".py"))
+    is_python = 1;
+
   stream = fdopen (fd, FOPEN_RT);
-  script_from_file (stream, file);
+
+  if (is_python)
+    source_python_script (stream, file);
+  else
+    script_from_file (stream, file);
 
   do_cleanups (old_cleanups);
 }
 
-/* Return the source_verbose global variable to its previous state
-   on exit from the source command, by whatever means.  */
-static void
-source_verbose_cleanup (void *old_value)
+/* A helper for source_command.  Look for an argument in *ARGS.
+   Update *ARGS by stripping leading whitespace.  If an argument is
+   found, return it (a character).  Otherwise, return 0.  */
+static int
+find_argument (char **args)
 {
-  source_verbose = *(int *)old_value;
-  xfree (old_value);
+  int result = 0;
+  while (isspace ((*args)[0]))
+    ++*args;
+  if ((*args)[0] == '-' && isalpha ((*args)[1]))
+    {
+      result = (*args)[1];
+      *args += 3;
+    }
+  return result;
 }
 
 static void
 source_command (char *args, int from_tty)
 {
   struct cleanup *old_cleanups;
-  char *file = args;
-  int *old_source_verbose = xmalloc (sizeof(int));
 
-  *old_source_verbose = source_verbose;
-  old_cleanups = make_cleanup (source_verbose_cleanup, old_source_verbose);
+  old_cleanups = make_cleanup_restore_integer (&source_verbose);
+  make_cleanup_restore_integer (&source_python);
 
   /* -v causes the source command to run in verbose mode.
      We still have to be able to handle filenames with spaces in a
@@ -502,23 +520,28 @@ source_command (char *args, int from_tty)
 
   if (args)
     {
-      /* Make sure leading white space does not break the comparisons.  */
-      while (isspace(args[0]))
-	args++;
-
-      /* Is -v the first thing in the string?  */
-      if (args[0] == '-' && args[1] == 'v' && isspace (args[2]))
+      while (1)
 	{
-	  source_verbose = 1;
-
-	  /* Trim -v and whitespace from the filename.  */
-	  file = &args[3];
-	  while (isspace (file[0]))
-	    file++;
+	  int arg = find_argument (&args);
+	  if (!arg)
+	    break;
+	  switch (arg)
+	    {
+	    case 'v':
+	      source_verbose = 1;
+	      break;
+	    case 'p':
+	      source_python = 1;
+	      break;
+	    default:
+	      error (_("unrecognized option -%c"), arg);
+	    }
 	}
     }
 
-  source_script (file, from_tty);
+  source_script (args, from_tty);
+
+  do_cleanups (old_cleanups);
 }
 
 
@@ -1281,6 +1304,8 @@ Commands defined in this way may have up to ten arguments."));
 Read commands from a file named FILE.\n\
 Optional -v switch (before the filename) causes each command in\n\
 FILE to be echoed as it is executed.\n\
+Optional -p switch (before the filename) causes FILE to be evaluated\n\
+as Python code.\n\
 Note that the file \"%s\" is read automatically in this way\n\
 when GDB is started."), gdbinit);
   c = add_cmd ("source", class_support, source_command,
diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index 166b84d..e6472ae 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -955,8 +955,10 @@ 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 an error occurs.
+@xref{Command Files,, Command files}.
 
 @item -eval-command @var{command}
 @itemx -ex @var{command}
@@ -17753,7 +17755,7 @@ command:
 @table @code
 @kindex source
 @cindex execute commands from a file
-@item source [@code{-v}] @var{filename}
+@item source [@code{-v}] [@code{-p}] @var{filename}
 Execute the command file @var{filename}.
 @end table
 
@@ -17770,6 +17772,11 @@ 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}, or if @code{-p} (for ``Python'')
+is given, then @value{GDBN} evaluates the contents of the file as
+Python code.  If Python support is not compiled in to @value{GDBN},
+then an error occurs.
+
 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/python/python.c b/gdb/python/python.c
index e778ac4..b275437 100644
--- a/gdb/python/python.c
+++ b/gdb/python/python.c
@@ -273,6 +273,22 @@ execute_gdb_command (PyObject *self, PyObject *args)
   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);
+}
+
 \f
 
 /* Printing.  */
@@ -335,6 +351,13 @@ 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)
+{
+  fclose (stream);
+  error (_("Python scripting is not supported in this copy of GDB."));
+}
+
 #endif /* HAVE_PYTHON */
 
 \f
diff --git a/gdb/python/python.h b/gdb/python/python.h
index e63c447..5a6a067 100644
--- a/gdb/python/python.h
+++ b/gdb/python/python.h
@@ -26,4 +26,6 @@ extern struct value *values_in_python;
 
 void eval_python_from_control_command (struct command_line *);
 
+void source_python_script (FILE *stream, char *file);
+
 #endif /* GDB_PYTHON_H */
diff --git a/gdb/testsuite/gdb.base/help.exp b/gdb/testsuite/gdb.base/help.exp
index 4618a2c..ff2838a 100644
--- a/gdb/testsuite/gdb.base/help.exp
+++ b/gdb/testsuite/gdb.base/help.exp
@@ -603,7 +603,7 @@ gdb_test "help stepi" "Step one instruction exactly\.\[\r\n\]+Argument N means d
 gdb_test "help signal" "Continue program giving it signal.*" "help signal"
 # test help source
 # vxgdb reads .vxgdbinit
-gdb_test "help source" "Read commands from a file named FILE\.\[\r\n\]+Optional -v switch \\(before the filename\\) causes each command in\[\r\n\]+FILE to be echoed as it is executed\.\[\r\n\]+Note that the file \"\[^\"\]*\" is read automatically in this way\[\r\n\]+when GDB is started\." "help source"
+gdb_test "help source" "Read commands from a file named FILE\.\[\r\n\]+Optional -v switch \\(before the filename\\) causes each command in\[\r\n\]+FILE to be echoed as it is executed\.\[\r\n\]+Optional -p switch \\(before the filename\\) causes FILE to be evaluated\[\r\n\]+as Python code\\.\[\r\n\]+Note that the file \"\[^\"\]*\" is read automatically in this way\[\r\n\]+when GDB is started\." "help source"
 # test help stack
 test_class_help "stack" {
     "Examining the stack\..*\[\r\n\]+"
diff --git a/gdb/testsuite/gdb.python/python.exp b/gdb/testsuite/gdb.python/python.exp
index a0c9b39..51c1a24 100644
--- a/gdb/testsuite/gdb.python/python.exp
+++ b/gdb/testsuite/gdb.python/python.exp
@@ -71,3 +71,6 @@ gdb_py_test_multiple "indented multi-line python command" \
   "  print 'hello, world!'" "" \
   "foo ()" "" \
   "end" "hello, world!"
+
+gdb_test "source -p $srcdir/$subdir/source1" "yes"
+gdb_test "source $srcdir/$subdir/source2.py" "yes"
diff --git a/gdb/testsuite/gdb.python/source1 b/gdb/testsuite/gdb.python/source1
new file mode 100644
index 0000000..b7ca419
--- /dev/null
+++ b/gdb/testsuite/gdb.python/source1
@@ -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'
diff --git a/gdb/testsuite/gdb.python/source2.py b/gdb/testsuite/gdb.python/source2.py
new file mode 100644
index 0000000..3d12222
--- /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 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'