commit 29bf4e44f6392e402f15512e80295750691d436a
author Andrew McNamara <andrewm@object-craft.com.au> Tue Jan 11 04:49:53 2005 +0000
committer Andrew McNamara <andrewm@object-craft.com.au> Tue Jan 11 04:49:53 2005 +0000
tree b3c99d024c2e646ba8b0cd6a50c586d78c95f86e
parent a422c34b705cad292cc0c30998ae0e45006de0d6

Now that internal dialect type is immutable, and the dialect registry
only contains instances of the dialect type, we can refer directly to the
dialect instances rather than creating new ones. In other words, if the
dialect comes from the registry, and we apply no further modifications,
the reader/writer can use the dialect object directly.

Modules/_csv.c

diff --git a/Modules/_csv.c b/Modules/_csv.c
index 34870fc..e70e001 100644
--- a/Modules/_csv.c
+++ b/Modules/_csv.c
@@ -301,11 +301,12 @@
 	NULL
 };
 
-static int
-dialect_init(DialectObj * self, PyObject * args, PyObject * kwargs)
+static PyObject *
+dialect_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 {
-	int ret = -1;
-        PyObject *dialect = NULL;
+	DialectObj *self;
+	PyObject *ret = NULL;
+	PyObject *dialect = NULL;
 	PyObject *delimiter = NULL;
 	PyObject *doublequote = NULL;
 	PyObject *escapechar = NULL;
@@ -326,7 +327,35 @@
 					 &quoting,
 					 &skipinitialspace,
 					 &strict))
-                return -1;
+		return NULL;
+
+	if (dialect != NULL) {
+		if (IS_BASESTRING(dialect)) {
+			dialect = get_dialect_from_registry(dialect);
+			if (dialect == NULL)
+				return NULL;
+		}
+		else
+			Py_INCREF(dialect);
+		/* Can we reuse this instance? */
+		if (PyObject_TypeCheck(dialect, &Dialect_Type) &&
+		    delimiter == 0 &&
+		    doublequote == 0 &&
+		    escapechar == 0 &&
+		    lineterminator == 0 &&
+		    quotechar == 0 &&
+		    quoting == 0 &&
+		    skipinitialspace == 0 &&
+		    strict == 0)
+			return dialect;
+	}
+
+	self = (DialectObj *)type->tp_alloc(type, 0);
+	if (self == NULL) {
+		Py_XDECREF(dialect);
+		return NULL;
+	}
+	self->lineterminator = NULL;
 
 	Py_XINCREF(delimiter);
 	Py_XINCREF(doublequote);
@@ -337,16 +366,9 @@
 	Py_XINCREF(skipinitialspace);
 	Py_XINCREF(strict);
 	if (dialect != NULL) {
-		if (IS_BASESTRING(dialect)) {
-			dialect = get_dialect_from_registry(dialect);
-			if (dialect == NULL)
-				goto err;
-		} else
-			Py_INCREF(dialect);
 #define DIALECT_GETATTR(v, n) \
 		if (v == NULL) \
 			v = PyObject_GetAttrString(dialect, n)
-
 		DIALECT_GETATTR(delimiter, "delimiter");
 		DIALECT_GETATTR(doublequote, "doublequote");
 		DIALECT_GETATTR(escapechar, "escapechar");
@@ -356,7 +378,6 @@
 		DIALECT_GETATTR(skipinitialspace, "skipinitialspace");
 		DIALECT_GETATTR(strict, "strict");
 		PyErr_Clear();
-		Py_DECREF(dialect);
 	}
 
 	/* check types and convert to C values */
@@ -387,12 +408,13 @@
 		goto err;
 	}
 	if (self->lineterminator == 0) {
-                PyErr_SetString(PyExc_TypeError, "lineterminator must be set");
+		PyErr_SetString(PyExc_TypeError, "lineterminator must be set");
 		goto err;
 	}
 
-	ret = 0;
+	ret = (PyObject *)self;
 err:
+	Py_XDECREF(dialect);
 	Py_XDECREF(delimiter);
 	Py_XDECREF(doublequote);
 	Py_XDECREF(escapechar);
@@ -401,18 +423,7 @@
 	Py_XDECREF(quoting);
 	Py_XDECREF(skipinitialspace);
 	Py_XDECREF(strict);
-        return ret;
-}
-
-static PyObject *
-dialect_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
-{
-        DialectObj *self;
-        self = (DialectObj *)type->tp_alloc(type, 0);
-        if (self != NULL) {
-                self->lineterminator = NULL;
-        }
-        return (PyObject *)self;
+	return ret;
 }
 
 
@@ -459,8 +470,8 @@
 	0,					/* tp_descr_get */
 	0,					/* tp_descr_set */
 	0,					/* tp_dictoffset */
-	(initproc)dialect_init,			/* tp_init */
-	PyType_GenericAlloc,	                /* tp_alloc */
+	0,					/* tp_init */
+	0,					/* tp_alloc */
 	dialect_new,			        /* tp_new */
 	0,                           		/* tp_free */
 };