llvm-project/clang-tools-extra/clangd/ExpectedTypes.h
Kazu Hirata f71ffd3b73 [clang-tools-extra] Use std::optional instead of llvm::Optional (NFC)
This patch replaces (llvm::|)Optional< with std::optional<.  I'll post
a separate patch to clean up the "using" declarations, #include
"llvm/ADT/Optional.h", etc.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716
2023-01-07 20:19:42 -08:00

66 lines
2.7 KiB
C++

//===--- ExpectedTypes.h - Simplified C++ types -----------------*- C++-*--===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// A simplified model of C++ types that can be used to check whether they are
// convertible between each other for the purposes of code completion ranking
// without looking at the ASTs. Note that we don't aim to fully mimic the C++
// conversion rules, merely try to have a model that gives useful improvements
// to the code completion ranking.
//
// We define an encoding of AST types as opaque strings, which can be stored in
// the index. Similar types (such as `int` and `long`) are folded together,
// forming equivalence classes with the same encoding.
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_EXPECTEDTYPES_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_EXPECTEDTYPES_H
#include "clang/AST/Type.h"
#include "llvm/ADT/StringRef.h"
#include <optional>
namespace clang {
class CodeCompletionResult;
namespace clangd {
/// A representation of a type that can be computed based on clang AST and
/// compared for equality. The encoding is stable between different ASTs, this
/// allows the representation to be stored in the index and compared with types
/// coming from a different AST later.
/// OpaqueType is a strongly-typedefed std::string, you can get the underlying
/// string with raw().
class OpaqueType {
public:
/// Create a type from a code completion result.
static std::optional<OpaqueType>
fromCompletionResult(ASTContext &Ctx, const CodeCompletionResult &R);
/// Construct an instance from a clang::QualType. This is usually a
/// PreferredType from a clang's completion context.
static std::optional<OpaqueType> fromType(ASTContext &Ctx, QualType Type);
/// Get the raw byte representation of the type. You can only rely on the
/// types being equal iff their raw representation is the same. The particular
/// details of the used encoding might change over time and one should not
/// rely on it.
llvm::StringRef raw() const { return Data; }
friend bool operator==(const OpaqueType &L, const OpaqueType &R) {
return L.Data == R.Data;
}
friend bool operator!=(const OpaqueType &L, const OpaqueType &R) {
return !(L == R);
}
private:
static std::optional<OpaqueType> encode(ASTContext &Ctx, QualType Type);
explicit OpaqueType(std::string Data);
std::string Data;
};
} // namespace clangd
} // namespace clang
#endif