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 "llvm/Support/Errc.h"
12 
13 namespace clang {
14 namespace clangd {
15 
16 llvm::Optional<std::string> DraftStore::getDraft(PathRef File) const {
17   std::lock_guard<std::mutex> Lock(Mutex);
18 
19   auto It = Drafts.find(File);
20   if (It == Drafts.end())
21     return None;
22 
23   return It->second;
24 }
25 
26 std::vector<Path> DraftStore::getActiveFiles() const {
27   std::lock_guard<std::mutex> Lock(Mutex);
28   std::vector<Path> ResultVector;
29 
30   for (auto DraftIt = Drafts.begin(); DraftIt != Drafts.end(); DraftIt++)
31     ResultVector.push_back(DraftIt->getKey());
32 
33   return ResultVector;
34 }
35 
36 void DraftStore::addDraft(PathRef File, llvm::StringRef Contents) {
37   std::lock_guard<std::mutex> Lock(Mutex);
38 
39   Drafts[File] = Contents;
40 }
41 
42 llvm::Expected<std::string> DraftStore::updateDraft(
43     PathRef File, llvm::ArrayRef<TextDocumentContentChangeEvent> Changes) {
44   std::lock_guard<std::mutex> Lock(Mutex);
45 
46   auto EntryIt = Drafts.find(File);
47   if (EntryIt == Drafts.end()) {
48     return llvm::make_error<llvm::StringError>(
49         "Trying to do incremental update on non-added document: " + File,
50         llvm::errc::invalid_argument);
51   }
52 
53   std::string Contents = EntryIt->second;
54 
55   for (const TextDocumentContentChangeEvent &Change : Changes) {
56     if (!Change.range) {
57       Contents = Change.text;
58       continue;
59     }
60 
61     const Position &Start = Change.range->start;
62     llvm::Expected<size_t> StartIndex =
63         positionToOffset(Contents, Start, false);
64     if (!StartIndex)
65       return StartIndex.takeError();
66 
67     const Position &End = Change.range->end;
68     llvm::Expected<size_t> EndIndex = positionToOffset(Contents, End, false);
69     if (!EndIndex)
70       return EndIndex.takeError();
71 
72     if (*EndIndex < *StartIndex)
73       return llvm::make_error<llvm::StringError>(
74           llvm::formatv(
75               "Range's end position ({0}) is before start position ({1})", End,
76               Start),
77           llvm::errc::invalid_argument);
78 
79     // Since the range length between two LSP positions is dependent on the
80     // contents of the buffer we compute the range length between the start and
81     // end position ourselves and compare it to the range length of the LSP
82     // message to verify the buffers of the client and server are in sync.
83 
84     // EndIndex and StartIndex are in bytes, but Change.rangeLength is in UTF-16
85     // code units.
86     ssize_t ComputedRangeLength =
87         lspLength(Contents.substr(*StartIndex, *EndIndex - *StartIndex));
88 
89     if (Change.rangeLength && ComputedRangeLength != *Change.rangeLength)
90       return llvm::make_error<llvm::StringError>(
91           llvm::formatv("Change's rangeLength ({0}) doesn't match the "
92                         "computed range length ({1}).",
93                         *Change.rangeLength, ComputedRangeLength),
94           llvm::errc::invalid_argument);
95 
96     std::string NewContents;
97     NewContents.reserve(*StartIndex + Change.text.length() +
98                         (Contents.length() - *EndIndex));
99 
100     NewContents = Contents.substr(0, *StartIndex);
101     NewContents += Change.text;
102     NewContents += Contents.substr(*EndIndex);
103 
104     Contents = std::move(NewContents);
105   }
106 
107   EntryIt->second = Contents;
108   return Contents;
109 }
110 
111 void DraftStore::removeDraft(PathRef File) {
112   std::lock_guard<std::mutex> Lock(Mutex);
113 
114   Drafts.erase(File);
115 }
116 
117 } // namespace clangd
118 } // namespace clang
119