Merge pull request #179 from hpyproject/feature/raise-value-error-whe…

…n-hpybytes-from-string-and-size-called-with-null-pointer

Raise ValueError when HPyBytes_FromStringAndSize is called with null pointer.

hpy/devel/include/common/implementation.h

@@ -46,3 +46,21 @@ HPyAPI_STORAGE int
 _HPy_IMPL_NAME(Err_Occurred)(HPyContext ctx) {
     return PyErr_Occurred() ? 1 : 0;
 }
+
+/* bytes.h */
+
+HPyAPI_STORAGE HPy
+_HPy_IMPL_NAME(Bytes_FromStringAndSize)(HPyContext ctx, const char *v, HPy_ssize_t len)
+{
+    if (v == NULL) {
+        // The CPython API allows passing a null pointer to
+        // PyBytes_FromStringAndSize and returns uninitialized memory of the
+        // requested size which can then be initialized after the call.
+        // In HPy the underlying memory is opaque and so cannot be initialized
+        // after the call and so we raise an error instead.
+        HPyErr_SetString(ctx, ctx->h_ValueError,
+                         "NULL char * passed to HPyBytes_FromStringAndSize");
+        return HPy_NULL;
+    }
+    return _py2h(PyBytes_FromStringAndSize(v, len));
+}

hpy/tools/autogen/parse.py

@@ -222,6 +222,7 @@ def _visit_hpyslot_slot(self, node):
     '_HPy_Dump': None,
     'HPy_Type': 'PyObject_Type',
     'HPy_TypeCheck': None,
+    'HPyBytes_FromStringAndSize': None,
 }
 
 

test/test_hpybytes.py

@@ -68,3 +68,64 @@ def test_AS_STRING(self):
             @INIT
         """)
         assert mod.f(b'ABC') == 100*ord('A') + 10*ord('B') + ord('C')
+
+    def test_FromString(self):
+        mod = self.make_module("""
+            HPyDef_METH(f, "f", f_impl, HPyFunc_O)
+            static HPy f_impl(HPyContext ctx, HPy self, HPy arg)
+            {
+                char *buf;
+                buf = HPyBytes_AsString(ctx, arg);
+                return HPyBytes_FromString(ctx, buf);
+            }
+
+            @EXPORT(f)
+            @INIT
+        """)
+        assert mod.f(b"aaa") == b"aaa"
+        assert mod.f(b"") == b""
+
+    def test_FromStringAndSize(self):
+        import pytest
+        mod = self.make_module("""
+            HPyDef_METH(f, "f", f_impl, HPyFunc_VARARGS)
+            static HPy f_impl(HPyContext ctx, HPy self, HPy *args,
+                              HPy_ssize_t nargs)
+            {
+                HPy src;
+                long len;
+                char *buf;
+                if (!HPyArg_Parse(ctx, NULL, args, nargs, "Ol", &src, &len)) {
+                    return HPy_NULL;
+                }
+                buf = HPyBytes_AsString(ctx, src);
+                return HPyBytes_FromStringAndSize(ctx, buf, len);
+            }
+
+            HPyDef_METH(f_null, "f_null", f_null_impl, HPyFunc_VARARGS)
+            static HPy f_null_impl(HPyContext ctx, HPy self, HPy *args,
+                                   HPy_ssize_t nargs)
+            {
+                long len;
+                if (!HPyArg_Parse(ctx, NULL, args, nargs, "l", &len)) {
+                    return HPy_NULL;
+                }
+
+                return HPyBytes_FromStringAndSize(ctx, NULL, len);
+            }
+
+            @EXPORT(f)
+            @EXPORT(f_null)
+            @INIT
+        """)
+        assert mod.f(b"aaa", 3) == b"aaa"
+        assert mod.f(b"abc", 2) == b"ab"
+        assert mod.f(b"", 0) == b""
+        with pytest.raises(SystemError):
+            # negative size passed to HPyBytes_FromStringAndSize
+            mod.f(b"abc", -1)
+        for i in (-1, 0, 1):
+            with pytest.raises(ValueError) as err:
+                mod.f_null(i)
+            assert str(err.value) == (
+                "NULL char * passed to HPyBytes_FromStringAndSize")