79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
/* go-can-convert-interface.c -- can we convert to an interface?
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Copyright 2009 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include "runtime.h"
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#include "go-assert.h"
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#include "go-string.h"
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#include "go-type.h"
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#include "interface.h"
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/* Return whether we can convert from the type in FROM_DESCRIPTOR to
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the interface in TO_DESCRIPTOR. This is used for type
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switches. */
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_Bool
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__go_can_convert_to_interface (
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const struct __go_type_descriptor *to_descriptor,
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const struct __go_type_descriptor *from_descriptor)
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{
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const struct __go_interface_type *to_interface;
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int to_method_count;
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const struct __go_interface_method *to_method;
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const struct __go_uncommon_type *from_uncommon;
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int from_method_count;
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const struct __go_method *from_method;
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int i;
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/* In a type switch FROM_DESCRIPTOR can be NULL. */
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if (from_descriptor == NULL)
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return 0;
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__go_assert (to_descriptor->__code == GO_INTERFACE);
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to_interface = (const struct __go_interface_type *) to_descriptor;
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to_method_count = to_interface->__methods.__count;
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to_method = ((const struct __go_interface_method *)
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to_interface->__methods.__values);
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from_uncommon = from_descriptor->__uncommon;
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if (from_uncommon == NULL)
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{
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from_method_count = 0;
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from_method = NULL;
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}
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else
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{
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from_method_count = from_uncommon->__methods.__count;
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from_method = ((const struct __go_method *)
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from_uncommon->__methods.__values);
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}
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for (i = 0; i < to_method_count; ++i)
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{
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while (from_method_count > 0
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&& (!__go_ptr_strings_equal (from_method->__name,
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to_method->__name)
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|| !__go_ptr_strings_equal (from_method->__pkg_path,
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to_method->__pkg_path)))
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{
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++from_method;
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--from_method_count;
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}
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if (from_method_count == 0)
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return 0;
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if (!__go_type_descriptors_equal (from_method->__mtype,
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to_method->__type))
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return 0;
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++to_method;
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++from_method;
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--from_method_count;
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}
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return 1;
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}
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