clang  6.0.0svn
FileMatchTrie.h
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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 
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.
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
DominatorTree GraphTraits specialization so the DominatorTree can be iterable by generic graph iterat...
Definition: Dominators.h:26
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
A trie to efficiently match against the entries of the compilation database in order of matching suff...
Definition: FileMatchTrie.h:58
Dataflow Directional Tag Classes.
A node of the FileMatchTrie.