604d5f5bca
For example, consider cases where we want to propagate errors only in
specific instances:
auto result = read_data(); // something like ErrorOr<ByteBuffer>
if (result.is_error() && result.error().code() != EINTR)
continue;
auto bytes = TRY(result);
The TRY invocation will currently copy the byte buffer when the
expression (in this case, just a local variable) is stored into
_temporary_result.
This patch binds the expression to a reference to prevent such copies.
In less trival invocations (such as TRY(some_function()), this will
incur only temporary lifetime extensions, i.e. no functional change.
95 lines
3.6 KiB
C++
95 lines
3.6 KiB
C++
/*
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* Copyright (c) 2022, Gregory Bertilson <zaggy1024@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/DeprecatedString.h>
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#include <AK/Error.h>
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#include <AK/Format.h>
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#include <AK/SourceLocation.h>
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#include <errno.h>
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namespace Video {
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struct DecoderError;
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template<typename T>
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using DecoderErrorOr = ErrorOr<T, DecoderError>;
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enum class DecoderErrorCategory : u32 {
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Unknown,
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IO,
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NeedsMoreInput,
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EndOfStream,
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Memory,
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// The input is corrupted.
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Corrupted,
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// Invalid call.
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Invalid,
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// The input uses features that are not yet implemented.
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NotImplemented,
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};
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struct DecoderError {
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public:
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static DecoderError with_description(DecoderErrorCategory category, StringView description)
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{
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return DecoderError(category, description);
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}
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template<typename... Parameters>
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static DecoderError format(DecoderErrorCategory category, CheckedFormatString<Parameters...>&& format_string, Parameters const&... parameters)
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{
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AK::VariadicFormatParams<AK::AllowDebugOnlyFormatters::No, Parameters...> variadic_format_params { parameters... };
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return DecoderError::with_description(category, DeprecatedString::vformatted(format_string.view(), variadic_format_params));
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}
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static DecoderError from_source_location(DecoderErrorCategory category, StringView description, SourceLocation location = SourceLocation::current())
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{
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return DecoderError::format(category, "[{} @ {}:{}]: {}", location.function_name(), location.filename(), location.line_number(), description);
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}
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static DecoderError corrupted(StringView description, SourceLocation location = SourceLocation::current())
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{
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return DecoderError::from_source_location(DecoderErrorCategory::Corrupted, description, location);
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}
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static DecoderError not_implemented(SourceLocation location = SourceLocation::current())
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{
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return DecoderError::format(DecoderErrorCategory::NotImplemented, "{} is not implemented", location.function_name());
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}
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DecoderErrorCategory category() const { return m_category; }
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StringView description() const { return m_description; }
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StringView string_literal() const { return m_description; }
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private:
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DecoderError(DecoderErrorCategory category, DeprecatedString description)
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: m_category(category)
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, m_description(move(description))
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{
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}
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DecoderErrorCategory m_category { DecoderErrorCategory::Unknown };
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DeprecatedString m_description;
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};
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#define DECODER_TRY(category, expression) \
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({ \
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auto&& _result = ((expression)); \
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if (_result.is_error()) [[unlikely]] { \
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auto _error_string = _result.release_error().string_literal(); \
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return DecoderError::from_source_location( \
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((category)), _error_string, SourceLocation::current()); \
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} \
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static_assert(!::AK::Detail::IsLvalueReference<decltype(_result.release_value())>, \
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"Do not return a reference from a fallible expression"); \
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_result.release_value(); \
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})
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#define DECODER_TRY_ALLOC(expression) DECODER_TRY(DecoderErrorCategory::Memory, expression)
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}
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