Coverage Report

Created: 2020-09-22 08:39

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Tooling/Transformer/MatchConsumer.h
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//===--- MatchConsumer.h - MatchConsumer abstraction ------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file This file defines the *MatchConsumer* abstraction: a computation over
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/// match results, specifically the `ast_matchers::MatchFinder::MatchResult`
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/// class.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_TOOLING_TRANSFORMER_MATCH_CONSUMER_H_
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#define LLVM_CLANG_TOOLING_TRANSFORMER_MATCH_CONSUMER_H_
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#include "clang/AST/ASTTypeTraits.h"
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#include "clang/ASTMatchers/ASTMatchFinder.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/Errc.h"
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#include "llvm/Support/Error.h"
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namespace clang {
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namespace transformer {
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/// A failable computation over nodes bound by AST matchers.
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///
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/// The computation should report any errors though its return value (rather
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/// than terminating the program) to enable usage in interactive scenarios like
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/// clang-query.
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///
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/// This is a central abstraction of the Transformer framework.
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template <typename T>
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using MatchConsumer =
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    std::function<Expected<T>(const ast_matchers::MatchFinder::MatchResult &)>;
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/// Creates an error that signals that a `MatchConsumer` expected a certain node
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/// to be bound by AST matchers, but it was not actually bound.
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inline llvm::Error notBoundError(llvm::StringRef Id) {
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  return llvm::make_error<llvm::StringError>(llvm::errc::invalid_argument,
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                                             "Id not bound: " + Id);
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}
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/// Chooses between the two consumers, based on whether \p ID is bound in the
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/// match.
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template <typename T>
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MatchConsumer<T> ifBound(std::string ID, MatchConsumer<T> TrueC,
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                         MatchConsumer<T> FalseC) {
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  return [=](const ast_matchers::MatchFinder::MatchResult &Result) {
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    auto &Map = Result.Nodes.getMap();
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    return (Map.find(ID) != Map.end() ? TrueC : FalseC)(Result);
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  };
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}
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/// A failable computation over nodes bound by AST matchers, with (limited)
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/// reflection via the `toString` method.
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///
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/// The computation should report any errors though its return value (rather
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/// than terminating the program) to enable usage in interactive scenarios like
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/// clang-query.
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///
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/// This is a central abstraction of the Transformer framework. It is a
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/// generalization of `MatchConsumer` and intended to replace it.
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template <typename T> class MatchComputation {
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public:
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  virtual ~MatchComputation() = default;
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  /// Evaluates the computation and (potentially) updates the accumulator \c
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  /// Result.  \c Result is undefined in the case of an error. `Result` is an
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  /// out parameter to optimize case where the computation involves composing
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  /// the result of sub-computation evaluations.
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  virtual llvm::Error eval(const ast_matchers::MatchFinder::MatchResult &Match,
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                           T *Result) const = 0;
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  /// Convenience version of `eval`, for the case where the computation is being
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  /// evaluated on its own.
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  llvm::Expected<T> eval(const ast_matchers::MatchFinder::MatchResult &R) const;
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  /// Constructs a string representation of the computation, for informational
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  /// purposes. The representation must be deterministic, but is not required to
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  /// be unique.
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  virtual std::string toString() const = 0;
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protected:
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  MatchComputation() = default;
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  // Since this is an abstract class, copying/assigning only make sense for
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  // derived classes implementing `clone()`.
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  MatchComputation(const MatchComputation &) = default;
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  MatchComputation &operator=(const MatchComputation &) = default;
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};
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template <typename T>
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llvm::Expected<T> MatchComputation<T>::eval(
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    const ast_matchers::MatchFinder::MatchResult &R) const {
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  T Output;
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  if (auto Err = eval(R, &Output))
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    return std::move(Err);
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  return Output;
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}
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} // namespace transformer
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} // namespace clang
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#endif // LLVM_CLANG_TOOLING_TRANSFORMER_MATCH_CONSUMER_H_