| 1 | //===--- HeaderMap.h - A file that acts like dir of symlinks ----*- 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 | // This file defines the HeaderMap interface. |
| 10 | // |
| 11 | //===----------------------------------------------------------------------===// |
| 12 | |
| 13 | #ifndef LLVM_CLANG_LEX_HEADERMAP_H |
| 14 | #define LLVM_CLANG_LEX_HEADERMAP_H |
| 15 | |
| 16 | #include "clang/Basic/LLVM.h" |
| 17 | #include "llvm/ADT/Optional.h" |
| 18 | #include "llvm/Support/Compiler.h" |
| 19 | #include "llvm/Support/MemoryBuffer.h" |
| 20 | #include <memory> |
| 21 | |
| 22 | namespace clang { |
| 23 | |
| 24 | class FileEntry; |
| 25 | class FileManager; |
| 26 | struct HMapBucket; |
| 27 | struct HMapHeader; |
| 28 | |
| 29 | /// Implementation for \a HeaderMap that doesn't depend on \a FileManager. |
| 30 | class HeaderMapImpl { |
| 31 | std::unique_ptr<const llvm::MemoryBuffer> FileBuffer; |
| 32 | bool NeedsBSwap; |
| 33 | |
| 34 | public: |
| 35 | HeaderMapImpl(std::unique_ptr<const llvm::MemoryBuffer> File, bool NeedsBSwap) |
| 36 | : FileBuffer(std::move(File)), NeedsBSwap(NeedsBSwap) {} |
| 37 | |
| 38 | // Check for a valid header and extract the byte swap. |
| 39 | static bool checkHeader(const llvm::MemoryBuffer &File, bool &NeedsByteSwap); |
| 40 | |
| 41 | /// If the specified relative filename is located in this HeaderMap return |
| 42 | /// the filename it is mapped to, otherwise return an empty StringRef. |
| 43 | StringRef lookupFilename(StringRef Filename, |
| 44 | SmallVectorImpl<char> &DestPath) const; |
| 45 | |
| 46 | /// Return the filename of the headermap. |
| 47 | StringRef getFileName() const; |
| 48 | |
| 49 | /// Print the contents of this headermap to stderr. |
| 50 | void dump() const; |
| 51 | |
| 52 | private: |
| 53 | unsigned getEndianAdjustedWord(unsigned X) const; |
| 54 | const HMapHeader &getHeader() const; |
| 55 | HMapBucket getBucket(unsigned BucketNo) const; |
| 56 | |
| 57 | /// Look up the specified string in the string table. If the string index is |
| 58 | /// not valid, return None. |
| 59 | Optional<StringRef> getString(unsigned StrTabIdx) const; |
| 60 | }; |
| 61 | |
| 62 | /// This class represents an Apple concept known as a 'header map'. To the |
| 63 | /// \#include file resolution process, it basically acts like a directory of |
| 64 | /// symlinks to files. Its advantages are that it is dense and more efficient |
| 65 | /// to create and process than a directory of symlinks. |
| 66 | class HeaderMap : private HeaderMapImpl { |
| 67 | HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File, bool BSwap) |
| 68 | : HeaderMapImpl(std::move(File), BSwap) {} |
| 69 | |
| 70 | public: |
| 71 | /// This attempts to load the specified file as a header map. If it doesn't |
| 72 | /// look like a HeaderMap, it gives up and returns null. |
| 73 | static std::unique_ptr<HeaderMap> Create(const FileEntry *FE, |
| 74 | FileManager &FM); |
| 75 | |
| 76 | /// Check to see if the specified relative filename is located in this |
| 77 | /// HeaderMap. If so, open it and return its FileEntry. If RawPath is not |
| 78 | /// NULL and the file is found, RawPath will be set to the raw path at which |
| 79 | /// the file was found in the file system. For example, for a search path |
| 80 | /// ".." and a filename "../file.h" this would be "../../file.h". |
| 81 | const FileEntry *LookupFile(StringRef Filename, FileManager &FM) const; |
| 82 | |
| 83 | using HeaderMapImpl::lookupFilename; |
| 84 | using HeaderMapImpl::getFileName; |
| 85 | using HeaderMapImpl::dump; |
| 86 | }; |
| 87 | |
| 88 | } // end namespace clang. |
| 89 | |
| 90 | #endif |
| 91 |