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