config: make type conversion explicit

The type of a config value depends on the tool that interprets
it. Parsing eagerly can lead to a situation where we return a bool
instead of a string or a number.

Let the user specify the type themselves by passing in a (str, type)
tuple into the mapping interface.

docs/config.rst

@@ -23,3 +23,19 @@ The Config type
    set multiple times in the configuration files.
 
 The :class:`Config` Mapping interface.
+
+Parsing the values
+===================
+
+Instead of a string, a tuple of `(str,type)` can be used to look up a
+key and parse it through the Git rules. E.g.
+
+    config['core.bare',bool]
+
+will return True if 'core.bare' is truthy.
+
+Truty values are: 'true', 1, 'on' or 'yes'. Falsy values are: 'false',
+0, 'off' and 'no'.
+
+Available types are `bool` and `int`. Not specifying a type returns a
+string.

src/config.c

@@ -170,29 +170,56 @@ Config_contains(Config *self, PyObject *py_key) {
 
 
 PyObject *
-Config_getitem(Config *self, PyObject *py_key)
+Config_getitem(Config *self, PyObject *py_input_key)
 {
-    int64_t value_int;
-    int err, value_bool;
+    int err;
     const char *value_str;
     const char *key;
-    PyObject* py_value, *tmp;
+    PyObject *py_key, *py_value, *tkey, *tmp_type = NULL;
+    PyTypeObject *py_type = NULL;
 
-    key = py_str_borrow_c_str(&tmp, py_key, NULL);
+    if (PyTuple_Check(py_input_key) && PyTuple_Size(py_input_key) == 2) {
+	    py_key = PyTuple_GetItem(py_input_key, 0);
+	    tmp_type = PyTuple_GetItem(py_input_key, 1);
+    } else {
+        py_key = py_input_key;
+    }
+
+    /* If passed a tuple, make sure the second item is a type */
+    if (tmp_type) {
+        if (!PyType_Check(tmp_type))
+            return NULL;
+        else
+            py_type = (PyTypeObject *) tmp_type;
+    }
+
+    key = py_str_borrow_c_str(&tkey, py_key, NULL);
     if (key == NULL)
         return NULL;
 
     err = git_config_get_string(&value_str, self->config, key);
-    Py_CLEAR(tmp);
+    Py_CLEAR(tkey);
     if (err < 0)
         goto cleanup;
 
-    if (git_config_parse_int64(&value_int, value_str) == 0)
-        py_value = PyLong_FromLongLong(value_int);
-    else if(git_config_parse_bool(&value_bool, value_str) == 0)
-        py_value = PyBool_FromLong(value_bool);
-    else
+    /* If the user specified a type, let's parse it */
+    if (py_type) {
+	    if (py_type == &PyBool_Type) {
+		    int value;
+            if ((err = git_config_parse_bool(&value, value_str)) < 0)
+                goto cleanup;
+
+            py_value = PyBool_FromLong(value);
+        } else if (py_type == &PyInteger_Type) {
+            int64_t value;
+            if ((err = git_config_parse_int64(&value, value_str)) < 0)
+                goto cleanup;
+
+            py_value = PyLong_FromLongLong(value);
+        }
+    } else {
         py_value = to_unicode(value_str, NULL, NULL);
+    }
 
 cleanup:
     if (err < 0) {

src/utils.h

@@ -47,6 +47,7 @@
   #undef PyLong_Check
   #define PyLong_Check PyInt_Check
   #define PyLong_FromLong PyInt_FromLong
+  #define PyInteger_Type PyInt_Type
   #define PyBytes_AS_STRING PyString_AS_STRING
   #define PyBytes_AsString PyString_AsString
   #define PyBytes_AsStringAndSize PyString_AsStringAndSize
@@ -57,6 +58,7 @@
   #define to_path(x) to_bytes(x)
   #define to_encoding(x) to_bytes(x)
 #else
+  #define PyInteger_Type PyLong_Type
   #define to_path(x) to_unicode(x, Py_FileSystemDefaultEncoding, "strict")
   #define to_encoding(x) PyUnicode_DecodeASCII(x, strlen(x), "strict")
 #endif

test/test_config.py

@@ -74,7 +74,7 @@ class ConfigTest(utils.RepoTestCase):
 
         config_read = Config(CONFIG_FILENAME)
         self.assertTrue('core.bare' in config_read)
-        self.assertFalse(config_read['core.bare'])
+        self.assertFalse(config_read['core.bare',bool])
         self.assertTrue('core.editor' in config_read)
         self.assertEqual(config_read['core.editor'], 'ed')
 
@@ -88,9 +88,9 @@ class ConfigTest(utils.RepoTestCase):
 
         config.add_file(CONFIG_FILENAME, 0)
         self.assertTrue('this.that' in config)
-        self.assertTrue(config['this.that'])
+        self.assertTrue(config['this.that',bool])
         self.assertTrue('something.other.here' in config)
-        self.assertFalse(config['something.other.here'])
+        self.assertFalse(config['something.other.here',bool])
 
     def test_read(self):
         config = self.repo.config
@@ -103,11 +103,11 @@ class ConfigTest(utils.RepoTestCase):
                                  lambda: config['abc.def'])
 
         self.assertTrue('core.bare' in config)
-        self.assertFalse(config['core.bare'])
+        self.assertFalse(config['core.bare',bool])
         self.assertTrue('core.editor' in config)
         self.assertEqual(config['core.editor'], 'ed')
         self.assertTrue('core.repositoryformatversion' in config)
-        self.assertEqual(config['core.repositoryformatversion'], 0)
+        self.assertEqual(config['core.repositoryformatversion',int], 0)
 
         new_file = open(CONFIG_FILENAME, "w")
         new_file.write("[this]\n\tthat = foobar\n\tthat = foobeer\n")
@@ -129,7 +129,7 @@ class ConfigTest(utils.RepoTestCase):
         self.assertFalse('core.dummy1' in config)
         config['core.dummy1'] = 42
         self.assertTrue('core.dummy1' in config)
-        self.assertEqual(config['core.dummy1'], 42)
+        self.assertEqual(config['core.dummy1',int], 42)
 
         self.assertFalse('core.dummy2' in config)
         config['core.dummy2'] = 'foobar'