1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
//== BackgroundIndexStorage.cpp - Provide caching support to BackgroundIndex ==/
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "Logger.h"
#include "index/Background.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/SHA1.h"
namespace clang {
namespace clangd {
namespace {
using FileDigest = decltype(llvm::SHA1::hash({}));
static FileDigest digest(StringRef Content) {
return llvm::SHA1::hash({(const uint8_t *)Content.data(), Content.size()});
}
std::string getShardPathFromFilePath(llvm::StringRef ShardRoot,
llvm::StringRef FilePath) {
llvm::SmallString<128> ShardRootSS(ShardRoot);
llvm::sys::path::append(ShardRootSS, llvm::sys::path::filename(FilePath) +
"." + llvm::toHex(digest(FilePath)) +
".idx");
return ShardRootSS.str();
}
llvm::Error
writeAtomically(llvm::StringRef OutPath,
llvm::function_ref<void(llvm::raw_ostream &)> Writer) {
// Write to a temporary file first.
llvm::SmallString<128> TempPath;
int FD;
auto EC =
llvm::sys::fs::createUniqueFile(OutPath + ".tmp.%%%%%%%%", FD, TempPath);
if (EC)
return llvm::errorCodeToError(EC);
// Make sure temp file is destroyed on failure.
auto RemoveOnFail =
llvm::make_scope_exit([TempPath] { llvm::sys::fs::remove(TempPath); });
llvm::raw_fd_ostream OS(FD, /*shouldClose=*/true);
Writer(OS);
OS.close();
if (OS.has_error())
return llvm::errorCodeToError(OS.error());
// Then move to real location.
EC = llvm::sys::fs::rename(TempPath, OutPath);
if (EC)
return llvm::errorCodeToError(EC);
// If everything went well, we already moved the file to another name. So
// don't delete the file, as the name might be taken by another file.
RemoveOnFail.release();
return llvm::ErrorSuccess();
}
// Uses disk as a storage for index shards. Creates a directory called
// ".clangd/index/" under the path provided during construction.
class DiskBackedIndexStorage : public BackgroundIndexStorage {
std::string DiskShardRoot;
public:
// Sets DiskShardRoot to (Directory + ".clangd/index/") which is the base
// directory for all shard files.
DiskBackedIndexStorage(llvm::StringRef Directory) {
llvm::SmallString<128> CDBDirectory(Directory);
llvm::sys::path::append(CDBDirectory, ".clangd", "index");
DiskShardRoot = CDBDirectory.str();
std::error_code OK;
std::error_code EC = llvm::sys::fs::create_directories(DiskShardRoot);
if (EC != OK) {
elog("Failed to create directory {0} for index storage: {1}",
DiskShardRoot, EC.message());
}
}
std::unique_ptr<IndexFileIn>
loadShard(llvm::StringRef ShardIdentifier) const override {
const std::string ShardPath =
getShardPathFromFilePath(DiskShardRoot, ShardIdentifier);
auto Buffer = llvm::MemoryBuffer::getFile(ShardPath);
if (!Buffer)
return nullptr;
if (auto I = readIndexFile(Buffer->get()->getBuffer()))
return llvm::make_unique<IndexFileIn>(std::move(*I));
else
elog("Error while reading shard {0}: {1}", ShardIdentifier,
I.takeError());
return nullptr;
}
llvm::Error storeShard(llvm::StringRef ShardIdentifier,
IndexFileOut Shard) const override {
return writeAtomically(
getShardPathFromFilePath(DiskShardRoot, ShardIdentifier),
[&Shard](llvm::raw_ostream &OS) { OS << Shard; });
}
};
// Doesn't persist index shards anywhere (used when the CDB dir is unknown).
// We could consider indexing into ~/.clangd/ or so instead.
class NullStorage : public BackgroundIndexStorage {
public:
std::unique_ptr<IndexFileIn>
loadShard(llvm::StringRef ShardIdentifier) const override {
return nullptr;
}
llvm::Error storeShard(llvm::StringRef ShardIdentifier,
IndexFileOut Shard) const override {
vlog("Couldn't find project for {0}, indexing in-memory only",
ShardIdentifier);
return llvm::Error::success();
}
};
// Creates and owns IndexStorages for multiple CDBs.
class DiskBackedIndexStorageManager {
public:
DiskBackedIndexStorageManager()
: IndexStorageMapMu(llvm::make_unique<std::mutex>()) {}
// Creates or fetches to storage from cache for the specified CDB.
BackgroundIndexStorage *operator()(llvm::StringRef CDBDirectory) {
std::lock_guard<std::mutex> Lock(*IndexStorageMapMu);
auto &IndexStorage = IndexStorageMap[CDBDirectory];
if (!IndexStorage)
IndexStorage = create(CDBDirectory);
return IndexStorage.get();
}
// Creates or fetches to storage from cache for the specified CDB.
BackgroundIndexStorage *createStorage(llvm::StringRef CDBDirectory);
private:
std::unique_ptr<BackgroundIndexStorage> create(llvm::StringRef CDBDirectory) {
if (CDBDirectory.empty())
return llvm::make_unique<NullStorage>();
return llvm::make_unique<DiskBackedIndexStorage>(CDBDirectory);
}
llvm::StringMap<std::unique_ptr<BackgroundIndexStorage>> IndexStorageMap;
std::unique_ptr<std::mutex> IndexStorageMapMu;
};
} // namespace
BackgroundIndexStorage::Factory
BackgroundIndexStorage::createDiskBackedStorageFactory() {
return DiskBackedIndexStorageManager();
}
} // namespace clangd
} // namespace clang
|
