Issue #4705: Fix the -u ("unbuffered binary stdout and stderr") command-line

flag to work properly. Furthermore, when specifying -u, the text stdout
and stderr streams have line-by-line buffering enabled (the default being
to buffer arbitrary chunks of data). Patch by Victor Stinner, test by me.

1 files changed, 76 insertions, 9 deletions

diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index c5f7e23..8a1af3b 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -88,6 +88,7 @@ int Py_UseClassExceptionsFlag = 1; /* Needed by bltinmodule.c: deprecated */
 int Py_FrozenFlag; /* Needed by getpath.c */
 int Py_IgnoreEnvironmentFlag; /* e.g. PYTHONPATH, PYTHONHOME */
 int Py_NoUserSiteDirectory = 0; /* for -s and site.py */
+int Py_UnbufferedStdioFlag = 0; /* Unbuffered binary std{in,out,err} */
 
 /* PyModule_GetWarningsModule is no longer necessary as of 2.6
 since _warnings is builtin.  This API should not be used. */
@@ -728,6 +729,75 @@ initsite(void)
 	}
 }
 
+static PyObject*
+create_stdio(PyObject* io,
+	int fd, int write_mode, char* name,
+	char* encoding, char* errors)
+{
+	PyObject *buf = NULL, *stream = NULL, *text = NULL, *raw = NULL;
+	const char* mode;
+	const PyObject *line_buffering;
+	int buffering;
+
+	if (Py_UnbufferedStdioFlag)
+		buffering = 0;
+	else
+		buffering = -1;
+	if (write_mode)
+		mode = "wb";
+	else
+		mode = "rb";
+	buf = PyObject_CallMethod(io, "open", "isiOOOi",
+				  fd, mode, buffering,
+				  Py_None, Py_None, Py_None, 0);
+	if (buf == NULL)
+		goto error;
+
+	if (!Py_UnbufferedStdioFlag) {
+		raw = PyObject_GetAttrString(buf, "raw");
+		if (raw == NULL)
+			goto error;
+	}
+	else {
+		raw = buf;
+		Py_INCREF(raw);
+	}
+
+	text = PyUnicode_FromString(name);
+	if (text == NULL || PyObject_SetAttrString(raw, "_name", text) < 0)
+		goto error;
+	Py_CLEAR(raw);
+	Py_CLEAR(text);
+
+	if (Py_UnbufferedStdioFlag)
+		line_buffering = Py_True;
+	else
+		line_buffering = Py_False;
+	stream = PyObject_CallMethod(io, "TextIOWrapper", "OsssO",
+				     buf, encoding, errors,
+				     "\n", line_buffering);
+	Py_CLEAR(buf);
+	if (stream == NULL)
+		goto error;
+
+	if (write_mode)
+		mode = "w";
+	else
+		mode = "r";
+	text = PyUnicode_FromString(mode);
+	if (!text || PyObject_SetAttrString(stream, "mode", text) < 0)
+		goto error;
+	Py_CLEAR(text);
+	return stream;
+
+error:
+	Py_XDECREF(buf);
+	Py_XDECREF(stream);
+	Py_XDECREF(text);
+	Py_XDECREF(raw);
+	return NULL;
+}
+
 /* Initialize sys.stdin, stdout, stderr and builtins.open */
 static int
 initstdio(void)
@@ -794,10 +864,9 @@ initstdio(void)
 #endif
 	}
 	else {
-		if (!(std = PyFile_FromFd(fd, "<stdin>", "r", -1, encoding, 
-					  errors, "\n", 0))) {
+		std = create_stdio(iomod, fd, 0, "<stdin>", encoding, errors);
+		if (std == NULL)
 			goto error;
-		}
 	} /* if (fd < 0) */
 	PySys_SetObject("__stdin__", std);
 	PySys_SetObject("stdin", std);
@@ -814,10 +883,9 @@ initstdio(void)
 #endif
 	}
 	else {
-		if (!(std = PyFile_FromFd(fd, "<stdout>", "w", -1, encoding, 
-					  errors, "\n", 0))) {
+		std = create_stdio(iomod, fd, 1, "<stdout>", encoding, errors);
+		if (std == NULL)
 			goto error;
-		}
 	} /* if (fd < 0) */
 	PySys_SetObject("__stdout__", std);
 	PySys_SetObject("stdout", std);
@@ -835,10 +903,9 @@ initstdio(void)
 #endif
 	}
 	else {
-		if (!(std = PyFile_FromFd(fd, "<stderr>", "w", -1, encoding,
-					  "backslashreplace", "\n", 0))) {
+		std = create_stdio(iomod, fd, 1, "<stderr>", encoding, "backslashreplace");
+		if (std == NULL)
 			goto error;
-		}
 	} /* if (fd < 0) */
 
 	/* Same as hack above, pre-import stderr's codec to avoid recursion