Patch #612627: Add encoding attribute to file objects, and determine

the terminal encoding on Windows and Unix.

Author: loewis

Doc/api/concrete.tex

@@ -2029,6 +2029,12 @@ \subsection{File Objects \label{fileObjects}}
   creation.
 \end{cfuncdesc}
 
+\begin{cfuncdesc}{int}{PyFile_Encoding}{PyFileObject *p, char *enc}
+  Set the file's encoding for Unicode output to \var{enc}. Return
+  1 on success and 0 on failure.
+  \versionadded{2.3}
+\end{cfuncdesc}
+
 \begin{cfuncdesc}{int}{PyFile_SoftSpace}{PyObject *p, int newflag}
   This function exists for internal use by the interpreter.  Sets the
   \member{softspace} attribute of \var{p} to \var{newflag} and

Doc/lib/libstdtypes.tex

@@ -1372,6 +1372,20 @@ \subsection{File Objects
 It may not be available on all file-like objects.
 \end{memberdesc}
 
+\begin{memberdesc}[file]{encoding}
+The encoding that this file uses. When Unicode strings are written
+to a file, they will be converted to byte strings using this encoding.
+In addition, when the file is connected to a terminal, the attribute
+gives the encoding that the terminal is likely to use (that 
+information might be incorrect if the user has misconfigured the 
+terminal). The attribute is read-only and may not be present on
+all file-like objects. It may also be \code{None}, in which case
+the file uses the system default encoding for converting Unicode
+strings.
+
+\versionadded{2.3}
+\end{memberdesc}
+
 \begin{memberdesc}[file]{mode}
 The I/O mode for the file.  If the file was created using the
 \function{open()} built-in function, this will be the value of the

Include/fileobject.h

@@ -24,6 +24,7 @@ typedef struct {
 	int f_newlinetypes;	/* Types of newlines seen */
 	int f_skipnextlf;	/* Skip next \n */
 #endif
+	PyObject *f_encoding;
 } PyFileObject;
 
 PyAPI_DATA(PyTypeObject) PyFile_Type;
@@ -33,6 +34,7 @@ PyAPI_DATA(PyTypeObject) PyFile_Type;
 
 PyAPI_FUNC(PyObject *) PyFile_FromString(char *, char *);
 PyAPI_FUNC(void) PyFile_SetBufSize(PyObject *, int);
+PyAPI_FUNC(int) PyFile_SetEncoding(PyObject *, const char *);
 PyAPI_FUNC(PyObject *) PyFile_FromFile(FILE *, char *, char *,
                                              int (*)(FILE *));
 PyAPI_FUNC(FILE *) PyFile_AsFile(PyObject *);

Misc/NEWS

@@ -12,6 +12,9 @@ What's New in Python 2.3 beta 2?
 Core and builtins
 -----------------
 
+- The encoding attribute has been added for file objects, and set to
+  the terminal encoding on Unix and Windows.
+
 - The softspace attribute of file objects became read-only by oversight.
   It's writable again.
 

Objects/fileobject.c

@@ -116,6 +116,7 @@ fill_file_fields(PyFileObject *f, FILE *fp, char *name, char *mode,
 
 	Py_DECREF(f->f_name);
 	Py_DECREF(f->f_mode);
+	Py_DECREF(f->f_encoding);
 #ifdef Py_USING_UNICODE
 	if (wname)
 		f->f_name = PyUnicode_FromObject(wname);
@@ -133,7 +134,9 @@ fill_file_fields(PyFileObject *f, FILE *fp, char *name, char *mode,
 	f->f_newlinetypes = NEWLINE_UNKNOWN;
 	f->f_skipnextlf = 0;
 #endif
-
+	Py_INCREF(Py_None);
+	f->f_encoding = Py_None;
+	
 	if (f->f_name == NULL || f->f_mode == NULL)
 		return NULL;
 	f->f_fp = fp;
@@ -302,6 +305,21 @@ PyFile_SetBufSize(PyObject *f, int bufsize)
 	}
 }
 
+/* Set the encoding used to output Unicode strings.
+   Returh 1 on success, 0 on failure. */
+
+int
+PyFile_SetEncoding(PyObject *f, const char *enc)
+{
+	PyFileObject *file = (PyFileObject*)f;
+	PyObject *str = PyString_FromString(enc);
+	if (!str)
+		return 0;
+	Py_DECREF(file->f_encoding);
+	file->f_encoding = str;
+	return 1;
+}
+
 static PyObject *
 err_closed(void)
 {
@@ -323,6 +341,7 @@ file_dealloc(PyFileObject *f)
 	}
 	Py_XDECREF(f->f_name);
 	Py_XDECREF(f->f_mode);
+	Py_XDECREF(f->f_encoding);
 	drop_readahead(f);
 	f->ob_type->tp_free((PyObject *)f);
 }
@@ -1667,6 +1686,8 @@ static PyMemberDef file_memberlist[] = {
 	 "file mode ('r', 'U', 'w', 'a', possibly with 'b' or '+' added)"},
 	{"name",	T_OBJECT,	OFF(f_name),	RO,
 	 "file name"},
+	{"encoding",	T_OBJECT,	OFF(f_encoding),	RO,
+	 "file encoding"},
 	/* getattr(f, "closed") is implemented without this table */
 	{NULL}	/* Sentinel */
 };
@@ -1851,6 +1872,8 @@ file_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 		((PyFileObject *)self)->f_name = not_yet_string;
 		Py_INCREF(not_yet_string);
 		((PyFileObject *)self)->f_mode = not_yet_string;
+		Py_INCREF(Py_None);
+		((PyFileObject *)self)->f_encoding = Py_None;
 	}
 	return self;
 }
@@ -2034,11 +2057,28 @@ PyFile_WriteObject(PyObject *v, PyObject *f, int flags)
 	}
 	else if (PyFile_Check(f)) {
 		FILE *fp = PyFile_AsFile(f);
+		PyObject *enc = ((PyFileObject*)f)->f_encoding;
+		int result;
 		if (fp == NULL) {
 			err_closed();
 			return -1;
 		}
+#ifdef Py_USING_UNICODE
+                if (PyUnicode_Check(v) && enc != Py_None) {
+			char *cenc = PyString_AS_STRING(enc);
+			value = PyUnicode_AsEncodedString(v, cenc, "strict");
+			if (value == NULL)
+				return -1;
+		} else {
+			value = v;
+			Py_INCREF(value);
+		}
+		result = PyObject_Print(value, fp, flags);
+		Py_DECREF(value);
+		return result;
+#else
 		return PyObject_Print(v, fp, flags);
+#endif
 	}
 	writer = PyObject_GetAttrString(f, "write");
 	if (writer == NULL)

Python/sysmodule.c

@@ -36,6 +36,15 @@ extern const char *PyWin_DLLVersionString;
 #include <unixlib.h>
 #endif
 
+#ifdef MS_WINDOWS
+#include <windows.h>
+#endif
+
+#ifdef HAVE_LANGINFO_H
+#include <locale.h>
+#include <langinfo.h>
+#endif
+
 PyObject *
 PySys_GetObject(char *name)
 {
@@ -881,6 +890,12 @@ _PySys_Init(void)
 	PyObject *m, *v, *sysdict;
 	PyObject *sysin, *sysout, *syserr;
 	char *s;
+#ifdef MS_WINDOWS
+	char buf[10];
+#endif
+#if defined(HAVE_LANGINFO_H) && defined(CODESET)
+	char *oldloc, *codeset;
+#endif
 
 	m = Py_InitModule3("sys", sys_methods, sys_doc);
 	sysdict = PyModule_GetDict(m);
@@ -890,6 +905,34 @@ _PySys_Init(void)
 	syserr = PyFile_FromFile(stderr, "<stderr>", "w", NULL);
 	if (PyErr_Occurred())
 		return NULL;
+#ifdef MS_WINDOWS
+	if(isatty(_fileno(stdin))){
+		sprintf(buf, "cp%d", GetConsoleCP());
+		if (!PyFile_SetEncoding(sysin, buf))
+			return NULL;
+	}
+	if(isatty(_fileno(stdout))) {
+		sprintf(buf, "cp%d", GetConsoleOutputCP());
+		if (!PyFile_SetEncoding(sysout, buf))
+			return NULL;
+	}
+#endif
+
+#if defined(HAVE_LANGINFO_H) && defined(CODESET)
+	oldloc = setlocale(LC_CTYPE, 0);
+	setlocale(LC_CTYPE, "");
+	codeset = nl_langinfo(CODESET);
+	setlocale(LC_CTYPE, oldloc);
+	if(codeset && isatty(fileno(stdin))){
+		if (!PyFile_SetEncoding(sysin, codeset))
+			return NULL;
+	}
+	if(codeset && isatty(fileno(stdout))) {
+		if (!PyFile_SetEncoding(sysout, codeset))
+			return NULL;
+	}
+#endif
+	
 	PyDict_SetItemString(sysdict, "stdin", sysin);
 	PyDict_SetItemString(sysdict, "stdout", sysout);
 	PyDict_SetItemString(sysdict, "stderr", syserr);