1 //===--- FileMatchTrie.h - --------------------------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file implements a match trie to find the matching file in a compilation 11 // database based on a given path in the presence of symlinks. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CLANG_TOOLING_FILEMATCHTRIE_H 16 #define LLVM_CLANG_TOOLING_FILEMATCHTRIE_H 17 18 #include "clang/Basic/LLVM.h" 19 #include <memory> 20 21 namespace llvm { 22 class StringRef; 23 } 24 25 namespace clang { 26 namespace tooling { 27 28 struct PathComparator { 29 virtual ~PathComparator() {} 30 virtual bool equivalent(StringRef FileA, StringRef FileB) const = 0; 31 }; 32 class FileMatchTrieNode; 33 34 /// \brief A trie to efficiently match against the entries of the compilation 35 /// database in order of matching suffix length. 36 /// 37 /// When a clang tool is supposed to operate on a specific file, we have to 38 /// find the corresponding file in the compilation database. Although entries 39 /// in the compilation database are keyed by filename, a simple string match 40 /// is insufficient because of symlinks. Commonly, a project hierarchy looks 41 /// like this: 42 /// /<project-root>/src/<path>/<somefile>.cc (used as input for the tool) 43 /// /<project-root>/build/<symlink-to-src>/<path>/<somefile>.cc (stored in DB) 44 /// 45 /// Furthermore, there might be symlinks inside the source folder or inside the 46 /// database, so that the same source file is translated with different build 47 /// options. 48 /// 49 /// For a given input file, the \c FileMatchTrie finds its entries in order 50 /// of matching suffix length. For each suffix length, there might be one or 51 /// more entries in the database. For each of those entries, it calls 52 /// \c llvm::sys::fs::equivalent() (injected as \c PathComparator). There might 53 /// be zero or more entries with the same matching suffix length that are 54 /// equivalent to the input file. Three cases are distinguished: 55 /// 0 equivalent files: Continue with the next suffix length. 56 /// 1 equivalent file: Best match found, return it. 57 /// >1 equivalent files: Match is ambiguous, return error. 58 class FileMatchTrie { 59 public: 60 FileMatchTrie(); 61 62 /// \brief Construct a new \c FileMatchTrie with the given \c PathComparator. 63 /// 64 /// The \c FileMatchTrie takes ownership of 'Comparator'. Used for testing. 65 FileMatchTrie(PathComparator* Comparator); 66 67 ~FileMatchTrie(); 68 69 /// \brief Insert a new absolute path. Relative paths are ignored. 70 void insert(StringRef NewPath); 71 72 /// \brief Finds the corresponding file in this trie. 73 /// 74 /// Returns file name stored in this trie that is equivalent to 'FileName' 75 /// according to 'Comparator', if it can be uniquely identified. If there 76 /// are no matches an empty \c StringRef is returned. If there are ambigious 77 /// matches, an empty \c StringRef is returned and a corresponding message 78 /// written to 'Error'. 79 StringRef findEquivalent(StringRef FileName, 80 raw_ostream &Error) const; 81 private: 82 FileMatchTrieNode *Root; 83 std::unique_ptr<PathComparator> Comparator; 84 }; 85 86 87 } // end namespace tooling 88 } // end namespace clang 89 90 #endif 91
