Coverage Report

Created: 2020-09-19 12:23

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/include/clang/Tooling/FileMatchTrie.h
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//===- FileMatchTrie.h ------------------------------------------*- 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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//  This file implements a match trie to find the matching file in a compilation
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//  database based on a given path in the presence of symlinks.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_TOOLING_FILEMATCHTRIE_H
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#define LLVM_CLANG_TOOLING_FILEMATCHTRIE_H
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#include "clang/Basic/LLVM.h"
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#include "llvm/ADT/StringRef.h"
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#include <memory>
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namespace clang {
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namespace tooling {
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class FileMatchTrieNode;
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struct PathComparator {
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  virtual ~PathComparator() = default;
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  virtual bool equivalent(StringRef FileA, StringRef FileB) const = 0;
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};
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/// A trie to efficiently match against the entries of the compilation
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/// database in order of matching suffix length.
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///
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/// When a clang tool is supposed to operate on a specific file, we have to
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/// find the corresponding file in the compilation database. Although entries
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/// in the compilation database are keyed by filename, a simple string match
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/// is insufficient because of symlinks. Commonly, a project hierarchy looks
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/// like this:
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///   /<project-root>/src/<path>/<somefile>.cc      (used as input for the tool)
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///   /<project-root>/build/<symlink-to-src>/<path>/<somefile>.cc (stored in DB)
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///
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/// Furthermore, there might be symlinks inside the source folder or inside the
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/// database, so that the same source file is translated with different build
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/// options.
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///
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/// For a given input file, the \c FileMatchTrie finds its entries in order
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/// of matching suffix length. For each suffix length, there might be one or
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/// more entries in the database. For each of those entries, it calls
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/// \c llvm::sys::fs::equivalent() (injected as \c PathComparator). There might
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/// be zero or more entries with the same matching suffix length that are
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/// equivalent to the input file. Three cases are distinguished:
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/// 0  equivalent files: Continue with the next suffix length.
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/// 1  equivalent file:  Best match found, return it.
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/// >1 equivalent files: Match is ambiguous, return error.
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class FileMatchTrie {
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public:
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  FileMatchTrie();
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  /// Construct a new \c FileMatchTrie with the given \c PathComparator.
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  ///
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  /// The \c FileMatchTrie takes ownership of 'Comparator'. Used for testing.
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  FileMatchTrie(PathComparator* Comparator);
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  ~FileMatchTrie();
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  /// Insert a new absolute path. Relative paths are ignored.
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  void insert(StringRef NewPath);
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  /// Finds the corresponding file in this trie.
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  ///
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  /// Returns file name stored in this trie that is equivalent to 'FileName'
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  /// according to 'Comparator', if it can be uniquely identified. If there
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  /// are no matches an empty \c StringRef is returned. If there are ambiguous
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  /// matches, an empty \c StringRef is returned and a corresponding message
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  /// written to 'Error'.
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  StringRef findEquivalent(StringRef FileName,
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                           raw_ostream &Error) const;
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private:
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  FileMatchTrieNode *Root;
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  std::unique_ptr<PathComparator> Comparator;
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};
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} // namespace tooling
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} // namespace clang
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#endif // LLVM_CLANG_TOOLING_FILEMATCHTRIE_H