Files
media_cas_packager_sdk/util/error_space.h
Widevine Buildbot 770fdbd1cc Adds 'virtual' and 'const' modifiers to methods in wv_cas_ecm.
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Expose header files under export/exported_root/util in media_cas_packager_sdk because util::Status is used in wv_cas_ecm.h

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=218632176
2018-10-25 05:20:40 +00:00

84 lines
2.5 KiB
C++

////////////////////////////////////////////////////////////////////////////////
// Copyright 2017 Google LLC.
//
// This software is licensed under the terms defined in the Widevine Master
// License Agreement. For a copy of this agreement, please contact
// widevine-licensing@google.com.
////////////////////////////////////////////////////////////////////////////////
#ifndef UTIL_ERROR_SPACE_H_
#define UTIL_ERROR_SPACE_H_
#include <string>
namespace widevine {
namespace util {
class ErrorSpace {
public:
std::string SpaceName() const { return space_name_func_(this); }
std::string String(int code) const { return code_to_string_func_(this, code); }
protected:
// typedef instead of using statements for SWIG compatibility.
typedef std::string (*SpaceNameFunc)(const ErrorSpace* space);
typedef std::string (*CodeToStringFunc)(const ErrorSpace* space, int code);
constexpr ErrorSpace(SpaceNameFunc space_name_func,
CodeToStringFunc code_to_string_func)
: space_name_func_(space_name_func),
code_to_string_func_(code_to_string_func) {}
private:
const SpaceNameFunc space_name_func_;
const CodeToStringFunc code_to_string_func_;
};
// Manages creation of error space subclasses.
template <typename T>
class ErrorSpaceImpl : public ErrorSpace {
public:
constexpr ErrorSpaceImpl()
: ErrorSpace(&ErrorSpaceImpl::SpaceNameImpl,
&ErrorSpaceImpl::CodeToStringImpl) {}
// Returns the canonical instance of the `T` error space.
static constexpr const T* Get();
private:
// These functions adapt the stateful implementation that takes a space
// pointer to stateless static methods, so that clients of ErrorSpaceImpl are
// safe to have constexpr global instances.
static std::string SpaceNameImpl(const ErrorSpace* /*space*/) {
return T::SpaceName();
}
static std::string CodeToStringImpl(const ErrorSpace* /*space*/, int code) {
return T::CodeToString(code);
}
};
namespace internal {
// Provides a global constexpr instance of the error space `T`.
// We need the indirection because ErrorSpaceImpl can't declare constexpr
// instances of T since it is not yet fully declared.
template <typename T>
struct ErrorSpaceInstance {
static constexpr T value = {};
};
template <typename T>
constexpr T ErrorSpaceInstance<T>::value;
} // namespace internal
template <typename T>
constexpr const T* ErrorSpaceImpl<T>::Get() {
return &internal::ErrorSpaceInstance<T>::value;
}
} // namespace util
} // namespace widevine
#endif // UTIL_ERROR_SPACE_H_