1//===--- ConfigProvider.cpp - Loading of user configuration ---------------===//
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#include "ConfigProvider.h"
10#include "Config.h"
11#include "ConfigFragment.h"
12#include "support/FileCache.h"
13#include "support/Path.h"
14#include "support/ThreadsafeFS.h"
15#include "support/Trace.h"
16#include "llvm/ADT/STLExtras.h"
17#include "llvm/ADT/StringMap.h"
18#include "llvm/ADT/StringRef.h"
19#include "llvm/Support/Path.h"
20#include <chrono>
21#include <mutex>
22#include <optional>
23#include <string>
24
25namespace clang {
26namespace clangd {
27namespace config {
28
29// Threadsafe cache around reading a YAML config file from disk.
30class FileConfigCache : public FileCache {
31 mutable llvm::SmallVector<CompiledFragment, 1> CachedValue;
32 std::string Directory;
33
34public:
35 FileConfigCache(llvm::StringRef Path, llvm::StringRef Directory)
36 : FileCache(Path), Directory(Directory) {}
37
38 void get(const ThreadsafeFS &TFS, DiagnosticCallback DC,
39 std::chrono::steady_clock::time_point FreshTime, bool Trusted,
40 std::vector<CompiledFragment> &Out) const {
41 read(
42 TFS, FreshTime,
43 Parse: [&](std::optional<llvm::StringRef> Data) {
44 CachedValue.clear();
45 if (Data)
46 for (auto &Fragment : Fragment::parseYAML(YAML: *Data, BufferName: path(), DC)) {
47 Fragment.Source.Directory = Directory;
48 Fragment.Source.Trusted = Trusted;
49 CachedValue.push_back(Elt: std::move(Fragment).compile(DC));
50 }
51 },
52 Read: [&]() { llvm::copy(Range&: CachedValue, Out: std::back_inserter(x&: Out)); });
53 }
54};
55
56std::unique_ptr<Provider> Provider::fromYAMLFile(llvm::StringRef AbsPath,
57 llvm::StringRef Directory,
58 const ThreadsafeFS &FS,
59 bool Trusted) {
60 class AbsFileProvider : public Provider {
61 mutable FileConfigCache Cache; // threadsafe
62 const ThreadsafeFS &FS;
63 bool Trusted;
64
65 std::vector<CompiledFragment>
66 getFragments(const Params &P, DiagnosticCallback DC) const override {
67 std::vector<CompiledFragment> Result;
68 Cache.get(TFS: FS, DC, FreshTime: P.FreshTime, Trusted, Out&: Result);
69 return Result;
70 };
71
72 public:
73 AbsFileProvider(llvm::StringRef Path, llvm::StringRef Directory,
74 const ThreadsafeFS &FS, bool Trusted)
75 : Cache(Path, Directory), FS(FS), Trusted(Trusted) {
76 assert(llvm::sys::path::is_absolute(Path));
77 }
78 };
79
80 return std::make_unique<AbsFileProvider>(args&: AbsPath, args&: Directory, args: FS, args&: Trusted);
81}
82
83std::unique_ptr<Provider>
84Provider::fromAncestorRelativeYAMLFiles(llvm::StringRef RelPath,
85 const ThreadsafeFS &FS, bool Trusted) {
86 class RelFileProvider : public Provider {
87 std::string RelPath;
88 const ThreadsafeFS &FS;
89 bool Trusted;
90
91 mutable std::mutex Mu;
92 // Keys are the (posix-style) ancestor directory, not the config within it.
93 // We only insert into this map, so pointers to values are stable forever.
94 // Mutex guards the map itself, not the values (which are threadsafe).
95 mutable llvm::StringMap<FileConfigCache> Cache;
96
97 std::vector<CompiledFragment>
98 getFragments(const Params &P, DiagnosticCallback DC) const override {
99 namespace path = llvm::sys::path;
100
101 if (P.Path.empty())
102 return {};
103
104 // Compute absolute paths to all ancestors (substrings of P.Path).
105 llvm::SmallVector<llvm::StringRef, 8> Ancestors;
106 for (auto Ancestor = absoluteParent(Path: P.Path); !Ancestor.empty();
107 Ancestor = absoluteParent(Path: Ancestor)) {
108 Ancestors.emplace_back(Args&: Ancestor);
109 }
110 // Ensure corresponding cache entries exist in the map.
111 llvm::SmallVector<FileConfigCache *, 8> Caches;
112 {
113 std::lock_guard<std::mutex> Lock(Mu);
114 for (llvm::StringRef Ancestor : Ancestors) {
115 auto It = Cache.find(Key: Ancestor);
116 // Assemble the actual config file path only once.
117 if (It == Cache.end()) {
118 llvm::SmallString<256> ConfigPath = Ancestor;
119 path::append(path&: ConfigPath, a: RelPath);
120 // Use native slashes for reading the file, affects diagnostics.
121 llvm::sys::path::native(path&: ConfigPath);
122 It = Cache.try_emplace(Key: Ancestor, Args: ConfigPath.str(), Args&: Ancestor).first;
123 }
124 Caches.push_back(Elt: &It->second);
125 }
126 }
127 // Finally query each individual file.
128 // This will take a (per-file) lock for each file that actually exists.
129 std::vector<CompiledFragment> Result;
130 for (FileConfigCache *Cache : llvm::reverse(C&: Caches))
131 Cache->get(TFS: FS, DC, FreshTime: P.FreshTime, Trusted, Out&: Result);
132 return Result;
133 };
134
135 public:
136 RelFileProvider(llvm::StringRef RelPath, const ThreadsafeFS &FS,
137 bool Trusted)
138 : RelPath(RelPath), FS(FS), Trusted(Trusted) {
139 assert(llvm::sys::path::is_relative(RelPath));
140 }
141 };
142
143 return std::make_unique<RelFileProvider>(args&: RelPath, args: FS, args&: Trusted);
144}
145
146std::unique_ptr<Provider>
147Provider::combine(std::vector<const Provider *> Providers) {
148 class CombinedProvider : public Provider {
149 std::vector<const Provider *> Providers;
150
151 std::vector<CompiledFragment>
152 getFragments(const Params &P, DiagnosticCallback DC) const override {
153 std::vector<CompiledFragment> Result;
154 for (const auto &Provider : Providers) {
155 for (auto &Fragment : Provider->getFragments(P, DC))
156 Result.push_back(x: std::move(Fragment));
157 }
158 return Result;
159 }
160
161 public:
162 CombinedProvider(std::vector<const Provider *> Providers)
163 : Providers(std::move(Providers)) {}
164 };
165
166 return std::make_unique<CombinedProvider>(args: std::move(Providers));
167}
168
169Config Provider::getConfig(const Params &P, DiagnosticCallback DC) const {
170 trace::Span Tracer("getConfig");
171 if (!P.Path.empty())
172 SPAN_ATTACH(Tracer, "path", P.Path);
173 Config C;
174 for (const auto &Fragment : getFragments(P, DC))
175 Fragment(P, C);
176 return C;
177}
178
179} // namespace config
180} // namespace clangd
181} // namespace clang
182

source code of clang-tools-extra/clangd/ConfigProvider.cpp