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//===--- Dex.h - Dex Symbol Index Implementation ----------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
/// \file
/// This defines Dex - a symbol index implementation based on query iterators
/// over symbol tokens, such as fuzzy matching trigrams, scopes, types, etc.
/// While consuming more memory and having longer build stage due to
/// preprocessing, Dex will have substantially lower latency. It will also allow
/// efficient symbol searching which is crucial for operations like code
/// completion, and can be very important for a number of different code
/// transformations which will be eventually supported by Clangd.
#include "Iterator.h"
#include "PostingList.h"
#include "Token.h"
#include "Trigram.h"
#include "index/Index.h"
#include "index/MemIndex.h"
#include "index/Relation.h"
#include "index/SymbolCollector.h"
namespace clang {
namespace clangd {
namespace dex {
/// In-memory Dex trigram-based index implementation.
// FIXME(kbobyrev): Introduce serialization and deserialization of the symbol
// index so that it can be loaded from the disk. Since static index is not
// changed frequently, it's safe to assume that it has to be built only once
// (when the clangd process starts). Therefore, it can be easier to store built
// index on disk and then load it if available.
class Dex : public SymbolIndex {
// All data must outlive this index.
template <typename SymbolRange, typename RefsRange, typename RelationsRange>
Dex(SymbolRange &&Symbols, RefsRange &&Refs, RelationsRange &&Relations)
: Corpus(0) {
for (auto &&Sym : Symbols)
for (auto &&Ref : Refs)
this->Refs.try_emplace(Ref.first, Ref.second);
for (auto &&Rel : Relations)
// Symbols and Refs are owned by BackingData, Index takes ownership.
template <typename SymbolRange, typename RefsRange, typename RelationsRange,
typename Payload>
Dex(SymbolRange &&Symbols, RefsRange &&Refs, RelationsRange &&Relations,
Payload &&BackingData, size_t BackingDataSize)
: Dex(std::forward<SymbolRange>(Symbols), std::forward<RefsRange>(Refs),
std::forward<RelationsRange>(Relations)) {
KeepAlive = std::shared_ptr<void>(
std::make_shared<Payload>(std::move(BackingData)), nullptr);
this->BackingDataSize = BackingDataSize;
/// Builds an index from slabs. The index takes ownership of the slab.
static std::unique_ptr<SymbolIndex> build(SymbolSlab, RefSlab, RelationSlab);
fuzzyFind(const FuzzyFindRequest &Req,
llvm::function_ref<void(const Symbol &)> Callback) const override;
void lookup(const LookupRequest &Req,
llvm::function_ref<void(const Symbol &)> Callback) const override;
void refs(const RefsRequest &Req,
llvm::function_ref<void(const Ref &)> Callback) const override;
void relations(const RelationsRequest &Req,
llvm::function_ref<void(const SymbolID &, const Symbol &)>
Callback) const override;
size_t estimateMemoryUsage() const override;
void buildIndex();
std::unique_ptr<Iterator> iterator(const Token &Tok) const;
createFileProximityIterator(llvm::ArrayRef<std::string> ProximityPaths) const;
createTypeBoostingIterator(llvm::ArrayRef<std::string> Types) const;
/// Stores symbols sorted in the descending order of symbol quality..
std::vector<const Symbol *> Symbols;
/// SymbolQuality[I] is the quality of Symbols[I].
std::vector<float> SymbolQuality;
llvm::DenseMap<SymbolID, const Symbol *> LookupTable;
/// Inverted index is a mapping from the search token to the posting list,
/// which contains all items which can be characterized by such search token.
/// For example, if the search token is scope "std::", the corresponding
/// posting list would contain all indices of symbols defined in namespace
/// std. Inverted index is used to retrieve posting lists which are processed
/// during the fuzzyFind process.
llvm::DenseMap<Token, PostingList> InvertedIndex;
dex::Corpus Corpus;
llvm::DenseMap<SymbolID, llvm::ArrayRef<Ref>> Refs;
static_assert(sizeof(RelationKind) == sizeof(uint8_t),
"RelationKind should be of same size as a uint8_t");
llvm::DenseMap<std::pair<SymbolID, uint8_t>, std::vector<SymbolID>> Relations;
std::shared_ptr<void> KeepAlive; // poor man's move-only std::any
// Size of memory retained by KeepAlive.
size_t BackingDataSize = 0;
/// Returns Search Token for a number of parent directories of given Path.
/// Should be used within the index build process.
/// This function is exposed for testing only.
std::vector<std::string> generateProximityURIs(llvm::StringRef URIPath);
} // namespace dex
} // namespace clangd
} // namespace clang