[patch] PR python/12149 (stderr output directed to stdout)

[Phil Muldoon <pmuldoon at redhat dot com>]

This patch addresses the bug in python/12149 where output from the Python
sys.stderr was being directed to stdout within GDB.  In this patch I
have updated gdb.write and flush to take a stream argument, and also
created a new class to deal with error output.

OK?

Cheers,

Phil

--

2011-03-17  Phil Muldoon  <pmuldoon@redhat.com>

        PR python/12149

	* python/python.c (gdbpy_write): Accept a stream argument and
	operate to the appropriate stream.
	(gdbpy_flush): Likewise.
	(_initialize_python): Add stream constants.
	(finish_python_initialization): Add GdbOutputErrorFile class.

2011-03-17  Phil Muldoon  <pmuldoon@redhat.com>

        PR python/12149

	* gdb.texinfo (Basic Python): Update gdb.write and flush text.

2011-03-17  Phil Muldoon  <pmuldoon@redhat.com>

        PR python/12149

	* gdb.python/python.exp: Add gdb.write tests..


--

Index: doc/gdb.texinfo
===================================================================
RCS file: /cvs/src/src/gdb/doc/gdb.texinfo,v
retrieving revision 1.813
diff -u -r1.813 gdb.texinfo
--- doc/gdb.texinfo	17 Mar 2011 09:36:16 -0000	1.813
+++ doc/gdb.texinfo	17 Mar 2011 17:16:06 -0000
@@ -20877,18 +20877,60 @@
 @end smallexample
 @end defun
 
-@findex gdb.write
-@defun write string
-Print a string to @value{GDBN}'s paginated standard output stream.
+@findex gdb.write 
+@defun write string @r{[}stream{]} 
+Print a string to @value{GDBN}'s paginated output stream.  The
+optional @var{stream} determines the stream to print to.  The default
+stream is @value{GDBN}'s standard output stream.  Possible stream
+values are:
+
+@table @code
+@findex STDOUT
+@findex gdb.STDOUT
+@item STDOUT
+@value{GDBN}'s standard output stream.
+
+@findex STDERR
+@findex gdb.STDERR
+@item STDERR
+@value{GDBN}'s error stream.
+
+@findex STDLOG
+@findex gdb.STDLOG
+@item STDLOG
+@value{GDBN}'s log stream.
+@end table
+
 Writing to @code{sys.stdout} or @code{sys.stderr} will automatically
-call this function.
+call this function and will automatically direct the output to the
+relevant stream.
 @end defun
 
 @findex gdb.flush
 @defun flush
-Flush @value{GDBN}'s paginated standard output stream.  Flushing
-@code{sys.stdout} or @code{sys.stderr} will automatically call this
-function.
+Flush a @value{GDBN} paginated stream.  The optional @var{stream}
+determines the stream to flush.  The default stream is @value{GDBN}'s
+standard output stream.  Possible stream values are:
+
+@table @code
+@findex STDOUT
+@findex gdb.STDOUT
+@item STDOUT
+@value{GDBN}'s standard output stream.
+
+@findex STDERR
+@findex gdb.STDERR
+@item STDERR
+@value{GDBN}'s error stream.
+
+@findex STDLOG
+@findex gdb.STDLOG
+@item STDLOG
+@value{GDBN}'s log stream.
+@end table
+
+Flushing @code{sys.stdout} or @code{sys.stderr} will automatically
+call this function for the relevant stream.
 @end defun
 
 @findex gdb.target_charset
Index: python/python.c
===================================================================
RCS file: /cvs/src/src/gdb/python/python.c,v
retrieving revision 1.62
diff -u -r1.62 python.c
--- python/python.c	14 Mar 2011 16:09:54 -0000	1.62
+++ python/python.c	17 Mar 2011 17:16:07 -0000
@@ -681,23 +681,69 @@
 /* Printing.  */
 
 /* A python function to write a single string using gdb's filtered
-   output stream.  */
+   output stream .  The optional keyword STREAM can be used to write
+   to a particular stream.  The default stream is to gdb_stdout.  */
+
 static PyObject *
-gdbpy_write (PyObject *self, PyObject *args)
+gdbpy_write (PyObject *self, PyObject *args, PyObject *kw)
 {
   char *arg;
-
-  if (! PyArg_ParseTuple (args, "s", &arg))
+  static char *keywords[] = {"text", "stream", NULL };
+  int stream_type = 0;
+  
+  if (! PyArg_ParseTupleAndKeywords (args, kw, "s|i", keywords, &arg,
+				     &stream_type))
     return NULL;
-  printf_filtered ("%s", arg);
+
+  switch (stream_type)
+    {
+    case 1:
+      {
+	fprintf_filtered (gdb_stderr, "%s", arg);
+	break;
+      }
+    case 2:
+      {
+	fprintf_filtered (gdb_stdlog, "%s", arg);
+	break;
+      }
+    default:
+      fprintf_filtered (gdb_stdout, "%s", arg);
+    }
+     
   Py_RETURN_NONE;
 }
 
-/* A python function to flush gdb's filtered output stream.  */
+/* A python function to flush a gdb stream.  The optional keyword
+   STREAM can be used to flush a particular stream.  The default stream
+   is gdb_stdout.  */
+
 static PyObject *
-gdbpy_flush (PyObject *self, PyObject *args)
+gdbpy_flush (PyObject *self, PyObject *args, PyObject *kw)
 {
-  gdb_flush (gdb_stdout);
+  static char *keywords[] = {"stream", NULL };
+  int stream_type = 0;
+  
+  if (! PyArg_ParseTupleAndKeywords (args, kw, "|i", keywords,
+				     &stream_type))
+    return NULL;
+
+  switch (stream_type)
+    {
+    case 1:
+      {
+	gdb_flush (gdb_stderr);
+	break;
+      }
+    case 2:
+      {
+	gdb_flush (gdb_stdlog);
+	break;
+      }
+    default:
+      gdb_flush (gdb_stdout);
+    }
+     
   Py_RETURN_NONE;
 }
 
@@ -975,6 +1021,11 @@
   PyModule_AddStringConstant (gdb_module, "TARGET_CONFIG",
 			      (char*) target_name);
 
+  /* Add stream constants.  */
+  PyModule_AddIntConstant (gdb_module, "STDOUT", 0);
+  PyModule_AddIntConstant (gdb_module, "STDERR", 1);
+  PyModule_AddIntConstant (gdb_module, "STDLOG", 2);
+  
   /* gdb.parameter ("data-directory") doesn't necessarily exist when the python
      script below is run (depending on order of _initialize_* functions).
      Define the initial value of gdb.PYTHONDIR here.  */
@@ -1068,7 +1119,7 @@
     return False\n\
 \n\
   def write(self, s):\n\
-    gdb.write(s)\n\
+    gdb.write(s, stream=gdb.STDOUT)\n   \
 \n\
   def writelines(self, iterable):\n\
     for line in iterable:\n\
@@ -1077,9 +1128,28 @@
   def flush(self):\n\
     gdb.flush()\n\
 \n\
-sys.stderr = GdbOutputFile()\n\
 sys.stdout = GdbOutputFile()\n\
 \n\
+class GdbOutputErrorFile:\n\
+  def close(self):\n\
+    # Do nothing.\n\
+    return None\n\
+\n\
+  def isatty(self):\n\
+    return False\n\
+\n\
+  def write(self, s):\n\
+    gdb.write(s, stream=gdb.STDERR)\n		\
+\n\
+  def writelines(self, iterable):\n\
+    for line in iterable:\n\
+      self.write(line)\n \
+\n\
+  def flush(self):\n\
+    gdb.flush()\n\
+\n\
+sys.stderr = GdbOutputErrorFile()\n\
+\n\
 # Ideally this would live in the gdb module, but it's intentionally written\n\
 # in python, and we need this to bootstrap the gdb module.\n\
 \n\
@@ -1199,10 +1269,9 @@
 Parse String and return an argv-like array.\n\
 Arguments are separate by spaces and may be quoted."
   },
-
-  { "write", gdbpy_write, METH_VARARGS,
+  { "write", (PyCFunction)gdbpy_write, METH_VARARGS | METH_KEYWORDS,
     "Write a string using gdb's filtered stream." },
-  { "flush", gdbpy_flush, METH_NOARGS,
+  { "flush", (PyCFunction)gdbpy_flush, METH_VARARGS | METH_KEYWORDS,
     "Flush gdb's filtered stdout stream." },
   { "selected_thread", gdbpy_selected_thread, METH_NOARGS,
     "selected_thread () -> gdb.InferiorThread.\n\
Index: testsuite/gdb.python/python.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.python/python.exp,v
retrieving revision 1.20
diff -u -r1.20 python.exp
--- testsuite/gdb.python/python.exp	10 Jan 2011 11:00:24 -0000	1.20
+++ testsuite/gdb.python/python.exp	17 Mar 2011 17:16:08 -0000
@@ -170,3 +170,11 @@
 gdb_test "python print len(symtab\[1\])" "1" "Test decode_line func1 length"
 gdb_test "python print symtab\[1\]\[0\].symtab" "gdb/testsuite/gdb.python/python-1.c.*" "Test decode_line func1 filename"
 gdb_test "python print symtab\[1\]\[0\].line" "19" "Test decode_line func1 line number"
+
+# gdb.write
+gdb_test "python print sys.stderr" ".*__main__.GdbOutputErrorFile instance at.*" "Test stderr location"
+gdb_test "python print sys.stdout" ".*__main__.GdbOutputFile instance at.*" "Test stdout location"
+gdb_test "python gdb.write(\"Foo\\n\")" "Foo" "Test default write"
+gdb_test "python gdb.write(\"Error stream\\n\", stream=gdb.STDERR)" "Error stream" "Test stderr write"
+gdb_test "python gdb.write(\"Normal stream\\n\", stream=gdb.STDOUT)" "Normal stream" "Test stdout write"
+gdb_test "python gdb.write(\"Log stream\\n\", stream=gdb.STDLOG)" "Log stream" "Test stdlog write"