From 2dde3d5ed9bc434c557c3128319dcdcd65facc23 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 25 Nov 2015 04:30:24 -0500
Subject: [PATCH 01/19] Initial function draft; note the comments!

Getting late.
---
 pysass.cpp | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)

diff --git a/pysass.cpp b/pysass.cpp
index 89484b75..69697e1e 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -404,6 +404,73 @@ static void _add_custom_functions(
     sass_option_set_c_functions(options, fn_list);
 }
 
+Sass_Import_List _call_py_importer_f(
+        const char* path,
+        Sass_Importer_Entry cb,
+        struct Sass_Compiler* comp
+) {
+    PyObject* pyfunc = (PyObject*)sass_importer_get_cookie(cb);
+    PyObject* py_path = PyUnicode_FromString(path);
+    PyObject* py_args = PyTuple_New(1);
+    PyObject* py_result = NULL;
+    Sass_Import_List sass_imports = NULL;
+    
+    PyTuple_SetItem(py_args, 0, py_path);
+    
+    if (!(py_result = PyObject_CallObject(pyfunc, py_args))) {
+        sass_imports = sass_make_import_list(1);
+        sass_imports[0] = sass_make_import_entry(path, 0, 0);
+        
+        
+        sass_import_set_error(list[0], strdup(message), 0, 0);
+        
+        Py_XDECREF(py_result);
+        return sass_imports;
+    }
+    
+    Py_XDECREF(py_args);
+        
+    if ( py_result == Py_None ) {
+        Py_XDECREF(py_result);
+        return 0;
+    }
+    
+    sass_imports = sass_make_import_list(PyList_Size(py_result));
+    
+    /* TODO: Iterator instead of literal list? Memory savings Python-side! */
+    for (i = 0; i < PyList_GET_SIZE(py_result); i += 1) {
+        PyObject* import_item = PyList_GET_ITEM(py_result, i);
+        char* path_str = NULL;  /* XXX: Memory leak? */
+        char* source_str = NULL;
+        char* sourcemap_str = NULL;
+        
+        /* TODO: Switch statement and error handling for default case. Better way? */
+        if ( PyTuple_GET_SIZE() == 1 ) {
+            PyArg_ParseTuple(import_item,
+                             PySass_IF_PY3("y", "s"),
+                             &path_str);
+        } else if ( PyTuple_GET_SIZE() == 2 ) {
+            PyArg_ParseTuple(import_item,
+                             PySass_IF_PY3("yy", "ss"),
+                             &path_str, &source_str);
+        } else if ( PyTuple_GET_SIZE() == 3 ) {
+            PyArg_ParseTuple(import_item,
+                             PySass_IF_PY3("yyy", "sss"),
+                             &path_str, &source_str, &sourcemap_str);
+        }
+        
+        /* POSSIBLE LEAK: owns arg source_str, sourcemap_str, but NOT path_str, ownership given @XXX?,
+           ref: https://github.com/sass/libsass/blob/master/docs/api-importer.md#return-imports */
+        sass_imports[i] = sass_make_import_entry(path_str, source_str, sourcemap_str)
+        
+        Py_XDECREF(import_item);
+    }
+    
+    Py_XDECREF(py_result);
+    
+    return sass_imports;
+}
+
 static PyObject *
 PySass_compile_string(PyObject *self, PyObject *args) {
     struct Sass_Context *ctx;

From 7981dd5943e35a4253f2dbedf5e524b0c0612666 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 25 Nov 2015 04:30:45 -0500
Subject: [PATCH 02/19] Documentation.

---
 sass.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/sass.py b/sass.py
index bf2498fd..1c6db3b4 100644
--- a/sass.py
+++ b/sass.py
@@ -209,6 +209,10 @@ def compile(**kwargs):
                      formatted. :const:`False` by default
     :type indented: :class:`bool`
     :returns: the compiled CSS string
+    :param importer: optional callback function.
+                     see also below `importer callbacks
+                     <importer-callbacks>`_ description
+    :type importer: :class:`collections.Callable`
     :rtype: :class:`str`
     :raises sass.CompileError: when it fails for any reason
                                (for example the given SASS has broken syntax)
@@ -336,6 +340,25 @@ def func_name(a, b):
               ...,
               custom_functions={func_name}
           )
+    
+    .. _importer-callbacks:
+
+    Newer versions of ``libsass`` allow developers to define a callback to be
+    called to be given a chance to process ``@import`` directives. You can
+    define yours by passing in a callable via the ``importer`` parameter.
+    
+    This callback must accept a single string argument representing the path
+    passed to the ``@import`` directive, and either return ``None`` to
+    indicate the path should be handled internally by ``libsass``, or a list
+    of one or more tuples, each in one of three forms:
+    
+    * A 1-tuple representing an alternate path to handle internally; or,
+    * A 2-tuple representing an alternate path and the content that path
+      represents; or,
+    * A 3-tuple representing the same as the 2-tuple with the addition of a
+      "sourcemap".
+    
+    All tuple values must be strings.
 
     .. versionadded:: 0.4.0
        Added ``source_comments`` and ``source_map_filename`` parameters.

From 2c1e233c9342cdddb884526a2c17d68a42b2500e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 25 Nov 2015 04:30:57 -0500
Subject: [PATCH 03/19] Initial test draft.

---
 sasstests.py | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/sasstests.py b/sasstests.py
index 3829e618..c1fd25de 100644
--- a/sasstests.py
+++ b/sasstests.py
@@ -260,7 +260,23 @@ def test_compile_string_sass_style(self):
         actual = sass.compile(string='a\n\tb\n\t\tcolor: blue;',
                               indented=True)
         assert actual == 'a b {\n  color: blue; }\n'
-
+    
+    # TODO: Test "nop" (return None) handling. Pseudo-code.
+    def test_compile_string_with_importer_callback(self):
+        def importer_callback(path):
+            return [
+                (path, '#' + path + ' { color: blue; }')
+                (path, '.' + path + ' { color: red; }')
+            ]
+        
+        source = '''@import('button')
+        a { color: green; }'''
+        
+        actual = sass.compile(string=source, importer=importer_callback)
+        assert actual == "#button { color: blue; }\n"
+                         ".button { color: red; }\n"
+                         "a { color: green; }"
+    
     def test_compile_string_deprecated_source_comments_line_numbers(self):
         source = '''a {
             b { color: blue; }

From bb75194d091097b59a2b0be649d49d8ca9a33e82 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 11:04:31 -0500
Subject: [PATCH 04/19] Memory management tweaks.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Now increments the reference count for the current list item, as it
isn’t auto-retained by `PyList_GET_ITEM`.

Additionally, corrected missing DECREF to prevent leak on early exit
due to error.
---
 pysass.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pysass.cpp b/pysass.cpp
index 69697e1e..19df1e0c 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -424,6 +424,7 @@ Sass_Import_List _call_py_importer_f(
         
         sass_import_set_error(list[0], strdup(message), 0, 0);
         
+        Py_XDECREF(py_args);
         Py_XDECREF(py_result);
         return sass_imports;
     }
@@ -444,6 +445,8 @@ Sass_Import_List _call_py_importer_f(
         char* source_str = NULL;
         char* sourcemap_str = NULL;
         
+        Py_INCREF(import_item);  /* GET_ITEM doesn't auto-retain. */
+        
         /* TODO: Switch statement and error handling for default case. Better way? */
         if ( PyTuple_GET_SIZE() == 1 ) {
             PyArg_ParseTuple(import_item,

From f65a640f5ccafbad121e96aadf56f1170b7ff2e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 11:04:50 -0500
Subject: [PATCH 05/19] Verified argument ownership, added missing strdup.

---
 pysass.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index 19df1e0c..ce613eba 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -462,8 +462,9 @@ Sass_Import_List _call_py_importer_f(
                              &path_str, &source_str, &sourcemap_str);
         }
         
-        /* POSSIBLE LEAK: owns arg source_str, sourcemap_str, but NOT path_str, ownership given @XXX?,
-           ref: https://github.com/sass/libsass/blob/master/docs/api-importer.md#return-imports */
+        if ( source_str ) source_str = strdup(source_str);
+        if ( sourcemap_str ) sourcemap_str = strdup(sourcemap_str);
+        
         sass_imports[i] = sass_make_import_entry(path_str, source_str, sourcemap_str)
         
         Py_XDECREF(import_item);

From 0f733a934b80ca96f1377f9024c1ed6f4de7d76f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 14:41:27 -0500
Subject: [PATCH 06/19] Updated C extension with wired-in importer callbacks.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Remarkably, this actually compiles.  I’m almost guaranteed missing
post-compile cleanup involving releasing the function reference
“cookies”.
---
 pysass.cpp | 67 ++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 53 insertions(+), 14 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index ce613eba..ef556413 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -414,6 +414,7 @@ Sass_Import_List _call_py_importer_f(
     PyObject* py_args = PyTuple_New(1);
     PyObject* py_result = NULL;
     Sass_Import_List sass_imports = NULL;
+    Py_ssize_t i;
     
     PyTuple_SetItem(py_args, 0, py_path);
     
@@ -421,8 +422,9 @@ Sass_Import_List _call_py_importer_f(
         sass_imports = sass_make_import_list(1);
         sass_imports[0] = sass_make_import_entry(path, 0, 0);
         
-        
-        sass_import_set_error(list[0], strdup(message), 0, 0);
+        sass_import_set_error(sass_imports[0],
+                              strdup("Error calling importer callback."),
+                              0, 0);
         
         Py_XDECREF(py_args);
         Py_XDECREF(py_result);
@@ -445,27 +447,32 @@ Sass_Import_List _call_py_importer_f(
         char* source_str = NULL;
         char* sourcemap_str = NULL;
         
-        Py_INCREF(import_item);  /* GET_ITEM doesn't auto-retain. */
+        /* GET_ITEM doesn't auto-retain. Future armoring relating to above
+           TODO, where iteration may return to the Python code context. */
+        Py_INCREF(import_item);
         
         /* TODO: Switch statement and error handling for default case. Better way? */
-        if ( PyTuple_GET_SIZE() == 1 ) {
+        if ( PyTuple_GET_SIZE(import_item) == 1 ) {
             PyArg_ParseTuple(import_item,
                              PySass_IF_PY3("y", "s"),
                              &path_str);
-        } else if ( PyTuple_GET_SIZE() == 2 ) {
+        } else if ( PyTuple_GET_SIZE(import_item) == 2 ) {
             PyArg_ParseTuple(import_item,
                              PySass_IF_PY3("yy", "ss"),
                              &path_str, &source_str);
-        } else if ( PyTuple_GET_SIZE() == 3 ) {
+        } else if ( PyTuple_GET_SIZE(import_item) == 3 ) {
             PyArg_ParseTuple(import_item,
                              PySass_IF_PY3("yyy", "sss"),
                              &path_str, &source_str, &sourcemap_str);
         }
         
+        /* We need to give copies of these arguments; libsass handles
+           deallocation of them later, whereas path_str is left flapping
+           in the breeze -- it's treated const, so that's okay. */
         if ( source_str ) source_str = strdup(source_str);
         if ( sourcemap_str ) sourcemap_str = strdup(sourcemap_str);
         
-        sass_imports[i] = sass_make_import_entry(path_str, source_str, sourcemap_str)
+        sass_imports[i] = sass_make_import_entry(path_str, source_str, sourcemap_str);
         
         Py_XDECREF(import_item);
     }
@@ -475,6 +482,31 @@ Sass_Import_List _call_py_importer_f(
     return sass_imports;
 }
 
+static void _add_custom_importers(
+        struct Sass_Options* options, PyObject* custom_importers
+) {
+    Py_ssize_t i;
+    Sass_Importer_List importer_list;
+   
+    importer_list = sass_make_importer_list(PyList_Size(custom_importers));
+    
+    for (i = 0; i < PyList_GET_SIZE(custom_importers); i += 1) {
+        PyObject* item = PyList_GET_ITEM(custom_importers, i);
+        int priority = 0;
+        PyObject* import_function = NULL;
+        
+        PyArg_ParseTuple(item,
+                         PySass_IF_PY3("iO", "iO"),
+                         &priority, &import_function);
+        
+        importer_list[i] = sass_make_importer(_call_py_importer_f,
+                                              priority,
+                                              import_function);
+    }
+    
+    sass_option_set_c_importers(options, importer_list);
+}
+
 static PyObject *
 PySass_compile_string(PyObject *self, PyObject *args) {
     struct Sass_Context *ctx;
@@ -485,13 +517,14 @@ PySass_compile_string(PyObject *self, PyObject *args) {
     Sass_Output_Style output_style;
     int source_comments, error_status, precision, indented;
     PyObject *custom_functions;
+    PyObject *custom_importers;
     PyObject *result;
-
+    
     if (!PyArg_ParseTuple(args,
-                          PySass_IF_PY3("yiiyiOi", "siisiOi"),
+                          PySass_IF_PY3("yiiyiOiO", "siisiOiO"),
                           &string, &output_style, &source_comments,
                           &include_paths, &precision,
-                          &custom_functions, &indented)) {
+                          &custom_functions, &indented, &custom_importers)) {
         return NULL;
     }
 
@@ -503,7 +536,8 @@ PySass_compile_string(PyObject *self, PyObject *args) {
     sass_option_set_precision(options, precision);
     sass_option_set_is_indented_syntax_src(options, indented);
     _add_custom_functions(options, custom_functions);
-
+    _add_custom_importers(options, custom_importers);
+    
     sass_compile_data_context(context);
 
     ctx = sass_data_context_get_context(context);
@@ -515,6 +549,7 @@ PySass_compile_string(PyObject *self, PyObject *args) {
         (short int) !error_status,
         error_status ? error_message : output_string
     );
+    
     sass_delete_data_context(context);
     return result;
 }
@@ -528,13 +563,16 @@ PySass_compile_filename(PyObject *self, PyObject *args) {
     const char *error_message, *output_string, *source_map_string;
     Sass_Output_Style output_style;
     int source_comments, error_status, precision;
-    PyObject *source_map_filename, *custom_functions, *result;
+    PyObject *source_map_filename, *custom_functions, *custom_importers,
+             *result;
+    
 
     if (!PyArg_ParseTuple(args,
-                          PySass_IF_PY3("yiiyiOO", "siisiOO"),
+                          PySass_IF_PY3("yiiyiOOiO", "siisiOOiO"),
                           &filename, &output_style, &source_comments,
                           &include_paths, &precision,
-                          &source_map_filename, &custom_functions)) {
+                          &source_map_filename, &custom_functions,
+                          &custom_importers)) {
         return NULL;
     }
 
@@ -558,6 +596,7 @@ PySass_compile_filename(PyObject *self, PyObject *args) {
     sass_option_set_include_path(options, include_paths);
     sass_option_set_precision(options, precision);
     _add_custom_functions(options, custom_functions);
+    _add_custom_importers(options, custom_importers);
 
     sass_compile_file_context(context);
 

From d504dc261f51efe9202baa32b5cde9125ef1f92e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 15:04:43 -0500
Subject: [PATCH 07/19] Updated documentation.

---
 sass.py | 46 +++++++++++++++++++++++++++++++++++++---------
 1 file changed, 37 insertions(+), 9 deletions(-)

diff --git a/sass.py b/sass.py
index 1c6db3b4..2bb64ad7 100644
--- a/sass.py
+++ b/sass.py
@@ -209,10 +209,10 @@ def compile(**kwargs):
                      formatted. :const:`False` by default
     :type indented: :class:`bool`
     :returns: the compiled CSS string
-    :param importer: optional callback function.
+    :param importers: optional callback functions.
                      see also below `importer callbacks
                      <importer-callbacks>`_ description
-    :type importer: :class:`collections.Callable`
+    :type importers: :class:`collections.Callable`
     :rtype: :class:`str`
     :raises sass.CompileError: when it fails for any reason
                                (for example the given SASS has broken syntax)
@@ -247,6 +247,10 @@ def compile(**kwargs):
     :type custom_functions: :class:`collections.Set`,
                             :class:`collections.Sequence`,
                             :class:`collections.Mapping`
+    :param importers: optional callback functions.
+                     see also below `importer callbacks
+                     <importer-callbacks>`_ description
+    :type importers: :class:`collections.Callable`
     :returns: the compiled CSS string, or a pair of the compiled CSS string
               and the source map string if ``source_comments='map'``
     :rtype: :class:`str`, :class:`tuple`
@@ -343,14 +347,23 @@ def func_name(a, b):
     
     .. _importer-callbacks:
 
-    Newer versions of ``libsass`` allow developers to define a callback to be
-    called to be given a chance to process ``@import`` directives. You can
-    define yours by passing in a callable via the ``importer`` parameter.
+    Newer versions of ``libsass`` allow developers to define callbacks to be
+    called and given a chance to process ``@import`` directives. You can
+    define yours by passing in a list of callables via the ``importers``
+    parameter. The callables must be passed as 2-tuples in the form:
+    
+    .. code-block:: python
+    
+        (priority_int, callback_fn)
+    
+    A priority of zero is acceptable; priority determines the order callbacks
+    are attempted.
     
-    This callback must accept a single string argument representing the path
+    These callbacks must accept a single string argument representing the path
     passed to the ``@import`` directive, and either return ``None`` to
-    indicate the path should be handled internally by ``libsass``, or a list
-    of one or more tuples, each in one of three forms:
+    indicate the path wasn't handled by that callback (to continue with others
+    or fall back on internal ``libsass`` filesystem behaviour) or a list of
+    one or more tuples, each in one of three forms:
     
     * A 1-tuple representing an alternate path to handle internally; or,
     * A 2-tuple representing an alternate path and the content that path
@@ -358,7 +371,22 @@ def func_name(a, b):
     * A 3-tuple representing the same as the 2-tuple with the addition of a
       "sourcemap".
     
-    All tuple values must be strings.
+    All tuple return values must be strings. As a not overly realistic
+    example:
+    
+    .. code-block:: python
+    
+        def my_importer(path):
+            return [(path, '#' + path + ' { color: red; }')]
+        
+        sass.compile(
+                ...,
+                importers=[(0, my_importer)]
+            )
+    
+    Now, within the style source, attempting to ``@import 'button';`` will
+    instead attach ``color: red`` as a property of an element with the
+    imported name.
 
     .. versionadded:: 0.4.0
        Added ``source_comments`` and ``source_map_filename`` parameters.

From 164951ba6833b11cb7e2417a965f26f85b422a87 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 15:07:30 -0500
Subject: [PATCH 08/19] Handle the case of no passed importers.

---
 pysass.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pysass.cpp b/pysass.cpp
index ef556413..f2f8ab14 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -487,6 +487,10 @@ static void _add_custom_importers(
 ) {
     Py_ssize_t i;
     Sass_Importer_List importer_list;
+    
+    if ( custom_importers == Py_None ) {
+        return;
+    }
    
     importer_list = sass_make_importer_list(PyList_Size(custom_importers));
     

From c8f1fea187cde629a226f8717a44b4e77bf21d01 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 17:39:20 -0500
Subject: [PATCH 09/19] Wire in the importer callback option.

---
 pysass.cpp |  3 +--
 sass.py    | 12 +++++++-----
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index f2f8ab14..2a5839a0 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -570,9 +570,8 @@ PySass_compile_filename(PyObject *self, PyObject *args) {
     PyObject *source_map_filename, *custom_functions, *custom_importers,
              *result;
     
-
     if (!PyArg_ParseTuple(args,
-                          PySass_IF_PY3("yiiyiOOiO", "siisiOOiO"),
+                          PySass_IF_PY3("yiiyiOOO", "siisiOOO"),
                           &filename, &output_style, &source_comments,
                           &include_paths, &precision,
                           &source_map_filename, &custom_functions,
diff --git a/sass.py b/sass.py
index 2bb64ad7..9890ba00 100644
--- a/sass.py
+++ b/sass.py
@@ -146,7 +146,7 @@ def __str__(self):
 
 def compile_dirname(
     search_path, output_path, output_style, source_comments, include_paths,
-    precision, custom_functions,
+    precision, custom_functions, importers
 ):
     fs_encoding = sys.getfilesystemencoding() or sys.getdefaultencoding()
     for dirpath, _, filenames in os.walk(search_path):
@@ -163,7 +163,7 @@ def compile_dirname(
             input_filename = input_filename.encode(fs_encoding)
             s, v, _ = compile_filename(
                 input_filename, output_style, source_comments, include_paths,
-                precision, None, custom_functions,
+                precision, None, custom_functions, importers
             )
             if s:
                 v = v.decode('UTF-8')
@@ -498,6 +498,8 @@ def my_importer(path):
             '- a set/sequence of named functions,\n'
             'not {1!r}'.format(SassFunction, custom_functions)
         )
+    
+    importers = kwargs.pop('importers', None)
 
     if 'string' in modes:
         string = kwargs.pop('string')
@@ -509,7 +511,7 @@ def my_importer(path):
                             repr(source_comments))
         s, v = compile_string(
             string, output_style, source_comments, include_paths, precision,
-            custom_functions, indented
+            custom_functions, indented, importers
         )
         if s:
             return v.decode('utf-8')
@@ -523,7 +525,7 @@ def my_importer(path):
             filename = filename.encode(fs_encoding)
         s, v, source_map = compile_filename(
             filename, output_style, source_comments, include_paths, precision,
-            source_map_filename, custom_functions,
+            source_map_filename, custom_functions, importers
         )
         if s:
             v = v.decode('utf-8')
@@ -568,7 +570,7 @@ def my_importer(path):
                              'output_dir)')
         s, v = compile_dirname(
             search_path, output_path, output_style, source_comments,
-            include_paths, precision, custom_functions,
+            include_paths, precision, custom_functions, importers
         )
         if s:
             return

From c032269c4885ad596fa5027724956a8ddea589d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 17:40:07 -0500
Subject: [PATCH 10/19] Capture errors during callback execution.

---
 pysass.cpp | 37 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 36 insertions(+), 1 deletion(-)

diff --git a/pysass.cpp b/pysass.cpp
index 2a5839a0..c71e345e 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -303,6 +303,37 @@ static union Sass_Value* _exception_to_sass_error() {
     return retv;
 }
 
+static PyObject* _exception_to_bytes() {
+    /* Grabs a Bytes instance for you to PySass_Bytes_AS_STRING.
+       Remember to Py_DECREF the object later!
+       TODO: This is a terrible violation of DRY, see above.
+    */
+    PyObject* retv = NULL;
+    PyObject* etype = NULL;
+    PyObject* evalue = NULL;
+    PyObject* etb = NULL;
+    PyErr_Fetch(&etype, &evalue, &etb);
+    PyErr_NormalizeException(&etype, &evalue, &etb);
+    {
+        PyObject* traceback_mod = PyImport_ImportModule("traceback");
+        PyObject* traceback_parts = PyObject_CallMethod(
+            traceback_mod, "format_exception", "OOO", etype, evalue, etb
+        );
+        PyList_Insert(traceback_parts, 0, PyUnicode_FromString("\n"));
+        PyObject* joinstr = PyUnicode_FromString("");
+        PyObject* result = PyUnicode_Join(joinstr, traceback_parts);
+        retv = PyUnicode_AsEncodedString(result, "UTF-8", "strict");
+        Py_DECREF(traceback_mod);
+        Py_DECREF(traceback_parts);
+        Py_DECREF(joinstr);
+        Py_DECREF(result);
+    }
+    Py_DECREF(etype);
+    Py_DECREF(evalue);
+    Py_DECREF(etb);
+    return retv;
+}
+
 static union Sass_Value* _to_sass_value(PyObject* value) {
     union Sass_Value* retv = NULL;
     PyObject* types_mod = PyImport_ImportModule("sass");
@@ -422,10 +453,14 @@ Sass_Import_List _call_py_importer_f(
         sass_imports = sass_make_import_list(1);
         sass_imports[0] = sass_make_import_entry(path, 0, 0);
         
+        PyObject* exc = _exception_to_bytes();
+        char* err = PySass_Bytes_AS_STRING(exc);
+        
         sass_import_set_error(sass_imports[0],
-                              strdup("Error calling importer callback."),
+                              err,
                               0, 0);
         
+        Py_XDECREF(exc);
         Py_XDECREF(py_args);
         Py_XDECREF(py_result);
         return sass_imports;

From 1d895a0f4e6a4bc6a6fef0a69380439e80060b35 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Thu, 26 Nov 2015 17:40:42 -0500
Subject: [PATCH 11/19] Test updates for real syntax.

Also shows what was emitted in the event of a failure.
---
 sasstests.py | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/sasstests.py b/sasstests.py
index c1fd25de..67e93ad4 100644
--- a/sasstests.py
+++ b/sasstests.py
@@ -264,18 +264,20 @@ def test_compile_string_sass_style(self):
     # TODO: Test "nop" (return None) handling. Pseudo-code.
     def test_compile_string_with_importer_callback(self):
         def importer_callback(path):
+            print("HERE")
             return [
-                (path, '#' + path + ' { color: blue; }')
-                (path, '.' + path + ' { color: red; }')
+                (path, '#' + path + ' { color: blue; }\n'),
+                (path, '.' + path + ' { color: red; }\n')
             ]
         
-        source = '''@import('button')
+        source = '''@import 'button';
         a { color: green; }'''
         
-        actual = sass.compile(string=source, importer=importer_callback)
-        assert actual == "#button { color: blue; }\n"
-                         ".button { color: red; }\n"
-                         "a { color: green; }"
+        actual = sass.compile(string=source,
+                              importers=[(0, importer_callback)])
+        assert actual == "#button { color: blue; }\n" \
+                         ".button { color: red; }\n" \
+                         "a { color: green; }", "got: " + actual
     
     def test_compile_string_deprecated_source_comments_line_numbers(self):
         source = '''a {

From b780b23e3e6185dbb96044cd076cdf26d11dc3ca Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Fri, 27 Nov 2015 01:40:58 -0500
Subject: [PATCH 12/19] Corrected test.

---
 sasstests.py | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/sasstests.py b/sasstests.py
index 67e93ad4..da260ca4 100644
--- a/sasstests.py
+++ b/sasstests.py
@@ -264,7 +264,6 @@ def test_compile_string_sass_style(self):
     # TODO: Test "nop" (return None) handling. Pseudo-code.
     def test_compile_string_with_importer_callback(self):
         def importer_callback(path):
-            print("HERE")
             return [
                 (path, '#' + path + ' { color: blue; }\n'),
                 (path, '.' + path + ' { color: red; }\n')
@@ -275,10 +274,16 @@ def importer_callback(path):
         
         actual = sass.compile(string=source,
                               importers=[(0, importer_callback)])
-        assert actual == "#button { color: blue; }\n" \
-                         ".button { color: red; }\n" \
-                         "a { color: green; }", "got: " + actual
-    
+        assert actual == """#button {
+  color: blue; }
+
+#button {
+  color: blue; }
+
+a {
+  color: green; }
+"""
+
     def test_compile_string_deprecated_source_comments_line_numbers(self):
         source = '''a {
             b { color: blue; }

From 78f526c657ad27d000e9b748188cf9fa807fdf98 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Fri, 27 Nov 2015 02:27:39 -0500
Subject: [PATCH 13/19] Cross-compatible `PyArg_ParseTuple` usage.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Turns out, it’s also more flexible this way.
---
 pysass.cpp | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index c71e345e..b5de12f4 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -488,17 +488,17 @@ Sass_Import_List _call_py_importer_f(
         
         /* TODO: Switch statement and error handling for default case. Better way? */
         if ( PyTuple_GET_SIZE(import_item) == 1 ) {
-            PyArg_ParseTuple(import_item,
-                             PySass_IF_PY3("y", "s"),
-                             &path_str);
+            fprintf(stderr, "il cb item 1-tup\n");
+            PyArg_ParseTuple(import_item, "es",
+                             0, &path_str);
         } else if ( PyTuple_GET_SIZE(import_item) == 2 ) {
-            PyArg_ParseTuple(import_item,
-                             PySass_IF_PY3("yy", "ss"),
-                             &path_str, &source_str);
+            fprintf(stderr, "il cb item 2-tup\n");
+            PyArg_ParseTuple(import_item, "eses",
+                             0, &path_str, 0, &source_str);
         } else if ( PyTuple_GET_SIZE(import_item) == 3 ) {
-            PyArg_ParseTuple(import_item,
-                             PySass_IF_PY3("yyy", "sss"),
-                             &path_str, &source_str, &sourcemap_str);
+            fprintf(stderr, "il cb item 3-tup\n");
+            PyArg_ParseTuple(import_item, "eseses",
+                             0, &path_str, 0, &source_str, 0, &sourcemap_str);
         }
         
         /* We need to give copies of these arguments; libsass handles
@@ -534,8 +534,7 @@ static void _add_custom_importers(
         int priority = 0;
         PyObject* import_function = NULL;
         
-        PyArg_ParseTuple(item,
-                         PySass_IF_PY3("iO", "iO"),
+        PyArg_ParseTuple(item, "iO",
                          &priority, &import_function);
         
         importer_list[i] = sass_make_importer(_call_py_importer_f,

From eaac1ef57f3996677a87f72c8d22184a7668f6b9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Fri, 27 Nov 2015 02:28:05 -0500
Subject: [PATCH 14/19] PEP-8 conformance.

---
 sass.py      | 24 ++++++++++++------------
 sasstests.py |  6 +++---
 2 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/sass.py b/sass.py
index 9890ba00..b8c80425 100644
--- a/sass.py
+++ b/sass.py
@@ -344,46 +344,46 @@ def func_name(a, b):
               ...,
               custom_functions={func_name}
           )
-    
+
     .. _importer-callbacks:
 
     Newer versions of ``libsass`` allow developers to define callbacks to be
     called and given a chance to process ``@import`` directives. You can
     define yours by passing in a list of callables via the ``importers``
     parameter. The callables must be passed as 2-tuples in the form:
-    
+
     .. code-block:: python
-    
+
         (priority_int, callback_fn)
-    
+
     A priority of zero is acceptable; priority determines the order callbacks
     are attempted.
-    
+
     These callbacks must accept a single string argument representing the path
     passed to the ``@import`` directive, and either return ``None`` to
     indicate the path wasn't handled by that callback (to continue with others
     or fall back on internal ``libsass`` filesystem behaviour) or a list of
     one or more tuples, each in one of three forms:
-    
+
     * A 1-tuple representing an alternate path to handle internally; or,
     * A 2-tuple representing an alternate path and the content that path
       represents; or,
     * A 3-tuple representing the same as the 2-tuple with the addition of a
       "sourcemap".
-    
+
     All tuple return values must be strings. As a not overly realistic
     example:
-    
+
     .. code-block:: python
-    
+
         def my_importer(path):
             return [(path, '#' + path + ' { color: red; }')]
-        
+
         sass.compile(
                 ...,
                 importers=[(0, my_importer)]
             )
-    
+
     Now, within the style source, attempting to ``@import 'button';`` will
     instead attach ``color: red`` as a property of an element with the
     imported name.
@@ -498,7 +498,7 @@ def my_importer(path):
             '- a set/sequence of named functions,\n'
             'not {1!r}'.format(SassFunction, custom_functions)
         )
-    
+
     importers = kwargs.pop('importers', None)
 
     if 'string' in modes:
diff --git a/sasstests.py b/sasstests.py
index da260ca4..c7b06ee5 100644
--- a/sasstests.py
+++ b/sasstests.py
@@ -260,7 +260,7 @@ def test_compile_string_sass_style(self):
         actual = sass.compile(string='a\n\tb\n\t\tcolor: blue;',
                               indented=True)
         assert actual == 'a b {\n  color: blue; }\n'
-    
+
     # TODO: Test "nop" (return None) handling. Pseudo-code.
     def test_compile_string_with_importer_callback(self):
         def importer_callback(path):
@@ -268,10 +268,10 @@ def importer_callback(path):
                 (path, '#' + path + ' { color: blue; }\n'),
                 (path, '.' + path + ' { color: red; }\n')
             ]
-        
+
         source = '''@import 'button';
         a { color: green; }'''
-        
+
         actual = sass.compile(string=source,
                               importers=[(0, importer_callback)])
         assert actual == """#button {

From 66d5097c5755498d5e33f4752ae83085d60cfcb4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 2 Dec 2015 02:26:17 -0500
Subject: [PATCH 15/19] Switch to PyObject_CallObject.

---
 pysass.cpp | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index b5de12f4..85d63ade 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -442,14 +442,15 @@ Sass_Import_List _call_py_importer_f(
 ) {
     PyObject* pyfunc = (PyObject*)sass_importer_get_cookie(cb);
     PyObject* py_path = PyUnicode_FromString(path);
-    PyObject* py_args = PyTuple_New(1);
     PyObject* py_result = NULL;
+    PyObject *iterator;
+    PyObject *import_item;
     Sass_Import_List sass_imports = NULL;
     Py_ssize_t i;
-    
-    PyTuple_SetItem(py_args, 0, py_path);
-    
-    if (!(py_result = PyObject_CallObject(pyfunc, py_args))) {
+
+    py_result = PyObject_CallObject(pyfunc, PySass_IF_PY3("y", "s"), py_path);
+
+    if (!py_result) {
         sass_imports = sass_make_import_list(1);
         sass_imports[0] = sass_make_import_entry(path, 0, 0);
         

From 3852d217b91cc05cd27d4c31a7919ce7864c12c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 2 Dec 2015 02:26:43 -0500
Subject: [PATCH 16/19] "Trailing whitespace" cleanup.

---
 pysass.cpp | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index 85d63ade..dcb23aac 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -453,14 +453,14 @@ Sass_Import_List _call_py_importer_f(
     if (!py_result) {
         sass_imports = sass_make_import_list(1);
         sass_imports[0] = sass_make_import_entry(path, 0, 0);
-        
+
         PyObject* exc = _exception_to_bytes();
         char* err = PySass_Bytes_AS_STRING(exc);
-        
+
         sass_import_set_error(sass_imports[0],
                               err,
                               0, 0);
-        
+
         Py_XDECREF(exc);
         Py_XDECREF(py_args);
         Py_XDECREF(py_result);
@@ -473,7 +473,7 @@ Sass_Import_List _call_py_importer_f(
         Py_XDECREF(py_result);
         return 0;
     }
-    
+
     sass_imports = sass_make_import_list(PyList_Size(py_result));
     
     /* TODO: Iterator instead of literal list? Memory savings Python-side! */
@@ -501,20 +501,20 @@ Sass_Import_List _call_py_importer_f(
             PyArg_ParseTuple(import_item, "eseses",
                              0, &path_str, 0, &source_str, 0, &sourcemap_str);
         }
-        
+
         /* We need to give copies of these arguments; libsass handles
            deallocation of them later, whereas path_str is left flapping
            in the breeze -- it's treated const, so that's okay. */
         if ( source_str ) source_str = strdup(source_str);
         if ( sourcemap_str ) sourcemap_str = strdup(sourcemap_str);
-        
+
         sass_imports[i] = sass_make_import_entry(path_str, source_str, sourcemap_str);
-        
+
         Py_XDECREF(import_item);
     }
-    
+
     Py_XDECREF(py_result);
-    
+
     return sass_imports;
 }
 

From 5e5172e43c4adbc7bca729d70875e8684d3f2b16 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 2 Dec 2015 02:27:15 -0500
Subject: [PATCH 17/19] Iterator use.

---
 pysass.cpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index dcb23aac..f91d4dad 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -475,10 +475,9 @@ Sass_Import_List _call_py_importer_f(
     }
 
     sass_imports = sass_make_import_list(PyList_Size(py_result));
-    
-    /* TODO: Iterator instead of literal list? Memory savings Python-side! */
-    for (i = 0; i < PyList_GET_SIZE(py_result); i += 1) {
-        PyObject* import_item = PyList_GET_ITEM(py_result, i);
+
+    iterator = PyObject_GetIter(obj);
+    while (import_item = PyIter_Next(iterator)) {
         char* path_str = NULL;  /* XXX: Memory leak? */
         char* source_str = NULL;
         char* sourcemap_str = NULL;
@@ -513,6 +512,7 @@ Sass_Import_List _call_py_importer_f(
         Py_XDECREF(import_item);
     }
 
+    Py_XDECREF(iterator);
     Py_XDECREF(py_result);
 
     return sass_imports;

From 92416a8b61b77f5fd1bd1d20310be02e8b9df15d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Wed, 2 Dec 2015 02:27:35 -0500
Subject: [PATCH 18/19] Clean-up.

---
 pysass.cpp | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/pysass.cpp b/pysass.cpp
index f91d4dad..5707c9a5 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -462,14 +462,11 @@ Sass_Import_List _call_py_importer_f(
                               0, 0);
 
         Py_XDECREF(exc);
-        Py_XDECREF(py_args);
         Py_XDECREF(py_result);
         return sass_imports;
     }
-    
-    Py_XDECREF(py_args);
-        
-    if ( py_result == Py_None ) {
+
+    if (py_result == Py_None) {
         Py_XDECREF(py_result);
         return 0;
     }
@@ -481,22 +478,15 @@ Sass_Import_List _call_py_importer_f(
         char* path_str = NULL;  /* XXX: Memory leak? */
         char* source_str = NULL;
         char* sourcemap_str = NULL;
-        
-        /* GET_ITEM doesn't auto-retain. Future armoring relating to above
-           TODO, where iteration may return to the Python code context. */
-        Py_INCREF(import_item);
-        
+
         /* TODO: Switch statement and error handling for default case. Better way? */
         if ( PyTuple_GET_SIZE(import_item) == 1 ) {
-            fprintf(stderr, "il cb item 1-tup\n");
             PyArg_ParseTuple(import_item, "es",
                              0, &path_str);
         } else if ( PyTuple_GET_SIZE(import_item) == 2 ) {
-            fprintf(stderr, "il cb item 2-tup\n");
             PyArg_ParseTuple(import_item, "eses",
                              0, &path_str, 0, &source_str);
         } else if ( PyTuple_GET_SIZE(import_item) == 3 ) {
-            fprintf(stderr, "il cb item 3-tup\n");
             PyArg_ParseTuple(import_item, "eseses",
                              0, &path_str, 0, &source_str, 0, &sourcemap_str);
         }

From 73a5a8cf56e0f1ecf2c841d9ffe233307871f783 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alice=20Bevan=E2=80=93McGregor?= <alice@gothcandy.com>
Date: Mon, 7 Dec 2015 16:00:28 -0500
Subject: [PATCH 19/19] Reference fix.

---
 pysass.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pysass.cpp b/pysass.cpp
index 5707c9a5..01701182 100644
--- a/pysass.cpp
+++ b/pysass.cpp
@@ -473,7 +473,7 @@ Sass_Import_List _call_py_importer_f(
 
     sass_imports = sass_make_import_list(PyList_Size(py_result));
 
-    iterator = PyObject_GetIter(obj);
+    iterator = PyObject_GetIter(py_result);
     while (import_item = PyIter_Next(iterator)) {
         char* path_str = NULL;  /* XXX: Memory leak? */
         char* source_str = NULL;