[clangd] Index API and implementations for relations

Summary:
This builds on the relations support added in D59407, D62459,
and D62471 to expose relations in SymbolIndex and its
implementations.

Reviewers: kadircet

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D62839

llvm-svn: 363481

1 files changed, 26 insertions, 4 deletions

diff --git a/clang-tools-extra/clangd/index/MemIndex.cpp b/clang-tools-extra/clangd/index/MemIndex.cpp
index 582091f07ab..2f3ff684531 100644
--- a/clang-tools-extra/clangd/index/MemIndex.cpp
+++ b/clang-tools-extra/clangd/index/MemIndex.cpp
@@ -16,12 +16,13 @@
 namespace clang {
 namespace clangd {
 
-std::unique_ptr<SymbolIndex> MemIndex::build(SymbolSlab Slab, RefSlab Refs) {
+std::unique_ptr<SymbolIndex> MemIndex::build(SymbolSlab Slab, RefSlab Refs,
+                                             RelationSlab Relations) {
   // Store Slab size before it is moved.
   const auto BackingDataSize = Slab.bytes() + Refs.bytes();
   auto Data = std::make_pair(std::move(Slab), std::move(Refs));
-  return llvm::make_unique<MemIndex>(Data.first, Data.second, std::move(Data),
-                                     BackingDataSize);
+  return llvm::make_unique<MemIndex>(Data.first, Data.second, Relations,
+                                     std::move(Data), BackingDataSize);
 }
 
 bool MemIndex::fuzzyFind(
@@ -84,8 +85,29 @@ void MemIndex::refs(const RefsRequest &Req,
   }
 }
 
+void MemIndex::relations(
+    const RelationsRequest &Req,
+    llvm::function_ref<void(const SymbolID &, const Symbol &)> Callback) const {
+  uint32_t Remaining =
+      Req.Limit.getValueOr(std::numeric_limits<uint32_t>::max());
+  for (const SymbolID &Subject : Req.Subjects) {
+    LookupRequest LookupReq;
+    auto It = Relations.find(std::make_pair(Subject, Req.Predicate));
+    if (It != Relations.end()) {
+      for (const auto &Obj : It->second) {
+        if (Remaining > 0) {
+          --Remaining;
+          LookupReq.IDs.insert(Obj);
+        }
+      }
+    }
+    lookup(LookupReq, [&](const Symbol &Object) { Callback(Subject, Object); });
+  }
+}
+
 size_t MemIndex::estimateMemoryUsage() const {
-  return Index.getMemorySize() + Refs.getMemorySize() + BackingDataSize;
+  return Index.getMemorySize() + Refs.getMemorySize() +
+         Relations.getMemorySize() + BackingDataSize;
 }
 
 } // namespace clangd