clang-tools-extra/clang-tidy/readability/ContainerSizeEmptyCheck.h

   1 //===--- ContainerSizeEmptyCheck.h - clang-tidy -----------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_CONTAINERSIZEEMPTYCHECK_H
  10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_CONTAINERSIZEEMPTYCHECK_H
  11
  12 #include "../ClangTidyCheck.h"
  13 #include <vector>
  14
  15 namespace clang::tidy::readability {
  16
  17 /// Checks whether a call to the `size()`/`length()` method can be replaced with
  18 /// a call to `empty()`.
  19 ///
  20 /// The emptiness of a container should be checked using the `empty()` method
  21 /// instead of the `size()` method. It is not guaranteed that `size()` is a
  22 /// constant-time function, and it is generally more efficient and also shows
  23 /// clearer intent to use `empty()`. Furthermore some containers may implement
  24 /// the `empty()` method but not implement the `size()` method. Using `empty()`
  25 /// whenever possible makes it easier to switch to another container in the
  26 /// future.
  27 class ContainerSizeEmptyCheck : public ClangTidyCheck {
  28 public:
  29   ContainerSizeEmptyCheck(StringRef Name, ClangTidyContext *Context);
  30   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
  31     return LangOpts.CPlusPlus;
  32   }
  33   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
  34   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
  35   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
  36   std::optional<TraversalKind> getCheckTraversalKind() const override {
  37     return TK_IgnoreUnlessSpelledInSource;
  38   }
  39
  40 private:
  41   std::vector<llvm::StringRef> ExcludedComparisonTypes;
  42 };
  43
  44 } // namespace clang::tidy::readability
  45
  46 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_READABILITY_CONTAINERSIZEEMPTYCHECK_H