1 //===--- DraftStore.cpp - File contents container ---------------*- 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 #include "DraftStore.h"
10 #include "SourceCode.h"
11 #include "support/Logger.h"
12 #include "llvm/ADT/StringExtras.h"
13 #include "llvm/Support/Errc.h"
14 #include "llvm/Support/VirtualFileSystem.h"
15 #include <memory>
16 
17 namespace clang {
18 namespace clangd {
19 
20 llvm::Optional<DraftStore::Draft> DraftStore::getDraft(PathRef File) const {
21   std::lock_guard<std::mutex> Lock(Mutex);
22 
23   auto It = Drafts.find(File);
24   if (It == Drafts.end())
25     return None;
26 
27   return It->second.D;
28 }
29 
30 std::vector<Path> DraftStore::getActiveFiles() const {
31   std::lock_guard<std::mutex> Lock(Mutex);
32   std::vector<Path> ResultVector;
33 
34   for (auto DraftIt = Drafts.begin(); DraftIt != Drafts.end(); DraftIt++)
35     ResultVector.push_back(std::string(DraftIt->getKey()));
36 
37   return ResultVector;
38 }
39 
40 static void increment(std::string &S) {
41   // Ensure there is a numeric suffix.
42   if (S.empty() || !llvm::isDigit(S.back())) {
43     S.push_back('0');
44     return;
45   }
46   // Increment the numeric suffix.
47   auto I = S.rbegin(), E = S.rend();
48   for (;;) {
49     if (I == E || !llvm::isDigit(*I)) {
50       // Reached start of numeric section, it was all 9s.
51       S.insert(I.base(), '1');
52       break;
53     }
54     if (*I != '9') {
55       // Found a digit we can increment, we're done.
56       ++*I;
57       break;
58     }
59     *I = '0'; // and keep incrementing to the left.
60   }
61 }
62 
63 static void updateVersion(DraftStore::Draft &D,
64                           llvm::StringRef SpecifiedVersion) {
65   if (!SpecifiedVersion.empty()) {
66     // We treat versions as opaque, but the protocol says they increase.
67     if (SpecifiedVersion.compare_numeric(D.Version) <= 0)
68       log("File version went from {0} to {1}", D.Version, SpecifiedVersion);
69     D.Version = SpecifiedVersion.str();
70   } else {
71     // Note that if D was newly-created, this will bump D.Version from "" to 1.
72     increment(D.Version);
73   }
74 }
75 
76 std::string DraftStore::addDraft(PathRef File, llvm::StringRef Version,
77                                  llvm::StringRef Contents) {
78   std::lock_guard<std::mutex> Lock(Mutex);
79 
80   auto &D = Drafts[File];
81   updateVersion(D.D, Version);
82   std::time(&D.MTime);
83   D.D.Contents = std::make_shared<std::string>(Contents);
84   return D.D.Version;
85 }
86 
87 void DraftStore::removeDraft(PathRef File) {
88   std::lock_guard<std::mutex> Lock(Mutex);
89 
90   Drafts.erase(File);
91 }
92 
93 namespace {
94 
95 /// A read only MemoryBuffer shares ownership of a ref counted string. The
96 /// shared string object must not be modified while an owned by this buffer.
97 class SharedStringBuffer : public llvm::MemoryBuffer {
98   const std::shared_ptr<const std::string> BufferContents;
99   const std::string Name;
100 
101 public:
102   BufferKind getBufferKind() const override {
103     return MemoryBuffer::MemoryBuffer_Malloc;
104   }
105 
106   StringRef getBufferIdentifier() const override { return Name; }
107 
108   SharedStringBuffer(std::shared_ptr<const std::string> Data, StringRef Name)
109       : BufferContents(std::move(Data)), Name(Name) {
110     assert(BufferContents && "Can't create from empty shared_ptr");
111     MemoryBuffer::init(BufferContents->c_str(),
112                        BufferContents->c_str() + BufferContents->size(),
113                        /*RequiresNullTerminator=*/true);
114   }
115 };
116 } // namespace
117 
118 llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> DraftStore::asVFS() const {
119   auto MemFS = llvm::makeIntrusiveRefCnt<llvm::vfs::InMemoryFileSystem>();
120   std::lock_guard<std::mutex> Guard(Mutex);
121   for (const auto &Draft : Drafts)
122     MemFS->addFile(Draft.getKey(), Draft.getValue().MTime,
123                    std::make_unique<SharedStringBuffer>(
124                        Draft.getValue().D.Contents, Draft.getKey()));
125   return MemFS;
126 }
127 } // namespace clangd
128 } // namespace clang
129