1 #include "Python.h"
2 #include "pycore_ast.h" // _PyAST_GetDocString()
3 #include "pycore_symtable.h" // _PyFutureFeatures
4 #include "pycore_unicodeobject.h" // _PyUnicode_EqualToASCIIString()
5
6 #define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
7
8 static int
future_check_features(_PyFutureFeatures * ff,stmt_ty s,PyObject * filename)9 future_check_features(_PyFutureFeatures *ff, stmt_ty s, PyObject *filename)
10 {
11 int i;
12
13 assert(s->kind == ImportFrom_kind);
14
15 asdl_alias_seq *names = s->v.ImportFrom.names;
16 for (i = 0; i < asdl_seq_LEN(names); i++) {
17 alias_ty name = (alias_ty)asdl_seq_GET(names, i);
18 const char *feature = PyUnicode_AsUTF8(name->name);
19 if (!feature)
20 return 0;
21 if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
22 continue;
23 } else if (strcmp(feature, FUTURE_GENERATORS) == 0) {
24 continue;
25 } else if (strcmp(feature, FUTURE_DIVISION) == 0) {
26 continue;
27 } else if (strcmp(feature, FUTURE_ABSOLUTE_IMPORT) == 0) {
28 continue;
29 } else if (strcmp(feature, FUTURE_WITH_STATEMENT) == 0) {
30 continue;
31 } else if (strcmp(feature, FUTURE_PRINT_FUNCTION) == 0) {
32 continue;
33 } else if (strcmp(feature, FUTURE_UNICODE_LITERALS) == 0) {
34 continue;
35 } else if (strcmp(feature, FUTURE_BARRY_AS_BDFL) == 0) {
36 ff->ff_features |= CO_FUTURE_BARRY_AS_BDFL;
37 } else if (strcmp(feature, FUTURE_GENERATOR_STOP) == 0) {
38 continue;
39 } else if (strcmp(feature, FUTURE_ANNOTATIONS) == 0) {
40 ff->ff_features |= CO_FUTURE_ANNOTATIONS;
41 } else if (strcmp(feature, "braces") == 0) {
42 PyErr_SetString(PyExc_SyntaxError,
43 "not a chance");
44 PyErr_RangedSyntaxLocationObject(filename,
45 name->lineno,
46 name->col_offset + 1,
47 name->end_lineno,
48 name->end_col_offset + 1);
49 return 0;
50 } else {
51 PyErr_Format(PyExc_SyntaxError,
52 UNDEFINED_FUTURE_FEATURE, feature);
53 PyErr_RangedSyntaxLocationObject(filename,
54 name->lineno,
55 name->col_offset + 1,
56 name->end_lineno,
57 name->end_col_offset + 1);
58 return 0;
59 }
60 }
61 return 1;
62 }
63
64 static int
future_parse(_PyFutureFeatures * ff,mod_ty mod,PyObject * filename)65 future_parse(_PyFutureFeatures *ff, mod_ty mod, PyObject *filename)
66 {
67 if (!(mod->kind == Module_kind || mod->kind == Interactive_kind)) {
68 return 1;
69 }
70
71 Py_ssize_t n = asdl_seq_LEN(mod->v.Module.body);
72 if (n == 0) {
73 return 1;
74 }
75
76 Py_ssize_t i = 0;
77 if (_PyAST_GetDocString(mod->v.Module.body) != NULL) {
78 i++;
79 }
80
81 for (; i < n; i++) {
82 stmt_ty s = (stmt_ty)asdl_seq_GET(mod->v.Module.body, i);
83
84 /* The only things that can precede a future statement
85 * are another future statement and a doc string.
86 */
87
88 if (s->kind == ImportFrom_kind && s->v.ImportFrom.level == 0) {
89 identifier modname = s->v.ImportFrom.module;
90 if (modname &&
91 _PyUnicode_EqualToASCIIString(modname, "__future__")) {
92 if (!future_check_features(ff, s, filename)) {
93 return 0;
94 }
95 ff->ff_location = SRC_LOCATION_FROM_AST(s);
96 }
97 else {
98 return 1;
99 }
100 }
101 else {
102 return 1;
103 }
104 }
105 return 1;
106 }
107
108
109 int
_PyFuture_FromAST(mod_ty mod,PyObject * filename,_PyFutureFeatures * ff)110 _PyFuture_FromAST(mod_ty mod, PyObject *filename, _PyFutureFeatures *ff)
111 {
112 ff->ff_features = 0;
113 ff->ff_location = (_Py_SourceLocation){-1, -1, -1, -1};
114
115 if (!future_parse(ff, mod, filename)) {
116 return 0;
117 }
118 return 1;
119 }
120