clang 19.0.0git
HeaderMap.h
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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
17#include "clang/Basic/LLVM.h"
19#include "llvm/ADT/StringMap.h"
20#include "llvm/Support/Compiler.h"
21#include "llvm/Support/MemoryBuffer.h"
22#include <memory>
23#include <optional>
24
25namespace clang {
26
27struct HMapBucket;
28struct HMapHeader;
29
30/// Implementation for \a HeaderMap that doesn't depend on \a FileManager.
32 std::unique_ptr<const llvm::MemoryBuffer> FileBuffer;
33 bool NeedsBSwap;
34 mutable llvm::StringMap<StringRef> ReverseMap;
35
36public:
37 HeaderMapImpl(std::unique_ptr<const llvm::MemoryBuffer> File, bool NeedsBSwap)
38 : FileBuffer(std::move(File)), NeedsBSwap(NeedsBSwap) {}
39
40 // Check for a valid header and extract the byte swap.
41 static bool checkHeader(const llvm::MemoryBuffer &File, bool &NeedsByteSwap);
42
43 // Make a call for every Key in the map.
44 template <typename Func> void forEachKey(Func Callback) const {
45 const HMapHeader &Hdr = getHeader();
46 unsigned NumBuckets = getEndianAdjustedWord(Hdr.NumBuckets);
47
48 for (unsigned Bucket = 0; Bucket < NumBuckets; ++Bucket) {
49 HMapBucket B = getBucket(Bucket);
50 if (B.Key != HMAP_EmptyBucketKey)
51 if (std::optional<StringRef> Key = getString(B.Key))
52 Callback(*Key);
53 }
54 }
55
56 /// If the specified relative filename is located in this HeaderMap return
57 /// the filename it is mapped to, otherwise return an empty StringRef.
58 StringRef lookupFilename(StringRef Filename,
59 SmallVectorImpl<char> &DestPath) const;
60
61 /// Return the filename of the headermap.
62 StringRef getFileName() const;
63
64 /// Print the contents of this headermap to stderr.
65 void dump() const;
66
67 /// Return key for specifed path.
68 StringRef reverseLookupFilename(StringRef DestPath) const;
69
70private:
71 unsigned getEndianAdjustedWord(unsigned X) const;
72 const HMapHeader &getHeader() const;
73 HMapBucket getBucket(unsigned BucketNo) const;
74
75 /// Look up the specified string in the string table. If the string index is
76 /// not valid, return std::nullopt.
77 std::optional<StringRef> getString(unsigned StrTabIdx) const;
78};
79
80/// This class represents an Apple concept known as a 'header map'. To the
81/// \#include file resolution process, it basically acts like a directory of
82/// symlinks to files. Its advantages are that it is dense and more efficient
83/// to create and process than a directory of symlinks.
84class HeaderMap : private HeaderMapImpl {
85 HeaderMap(std::unique_ptr<const llvm::MemoryBuffer> File, bool BSwap)
86 : HeaderMapImpl(std::move(File), BSwap) {}
87
88public:
89 /// This attempts to load the specified file as a header map. If it doesn't
90 /// look like a HeaderMap, it gives up and returns null.
91 static std::unique_ptr<HeaderMap> Create(FileEntryRef FE, FileManager &FM);
92
98};
99
100} // end namespace clang.
101
102#endif
Defines the clang::FileManager interface and associated types.
StringRef Filename
Definition: Format.cpp:2989
#define X(type, name)
Definition: Value.h:143
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified.
A reference to a FileEntry that includes the name of the file as it was accessed by the FileManager's...
Definition: FileEntry.h:57
Implements support for file system lookup, file system caching, and directory search management.
Definition: FileManager.h:53
Implementation for HeaderMap that doesn't depend on FileManager.
Definition: HeaderMap.h:31
StringRef getFileName() const
Return the filename of the headermap.
Definition: HeaderMap.cpp:109
HeaderMapImpl(std::unique_ptr< const llvm::MemoryBuffer > File, bool NeedsBSwap)
Definition: HeaderMap.h:37
void forEachKey(Func Callback) const
Definition: HeaderMap.h:44
StringRef reverseLookupFilename(StringRef DestPath) const
Return key for specifed path.
Definition: HeaderMap.cpp:231
void dump() const
Print the contents of this headermap to stderr.
Definition: HeaderMap.cpp:172
StringRef lookupFilename(StringRef Filename, SmallVectorImpl< char > &DestPath) const
If the specified relative filename is located in this HeaderMap return the filename it is mapped to,...
Definition: HeaderMap.cpp:197
static bool checkHeader(const llvm::MemoryBuffer &File, bool &NeedsByteSwap)
Definition: HeaderMap.cpp:66
This class represents an Apple concept known as a 'header map'.
Definition: HeaderMap.h:84
The JSON file list parser is used to communicate input to InstallAPI.
@ Create
'create' clause, allowed on Compute and Combined constructs, plus 'data', 'enter data',...
@ HMAP_EmptyBucketKey