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//===--- SemanticSelection.cpp -----------------------------------*- C++-*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "SemanticSelection.h"
#include "FindSymbols.h"
#include "ParsedAST.h"
#include "Protocol.h"
#include "Selection.h"
#include "SourceCode.h"
#include "clang/AST/DeclBase.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Tooling/Syntax/BuildTree.h"
#include "clang/Tooling/Syntax/Nodes.h"
#include "clang/Tooling/Syntax/Tree.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Error.h"
#include <queue>
#include <vector>
namespace clang {
namespace clangd {
namespace {
// Adds Range \p R to the Result if it is distinct from the last added Range.
// Assumes that only consecutive ranges can coincide.
void addIfDistinct(const Range &R, std::vector<Range> &Result) {
if (Result.empty() || Result.back() != R) {
Result.push_back(R);
}
}
llvm::Optional<FoldingRange> toFoldingRange(SourceRange SR,
const SourceManager &SM) {
const auto Begin = SM.getDecomposedLoc(SR.getBegin()),
End = SM.getDecomposedLoc(SR.getEnd());
// Do not produce folding ranges if either range ends is not within the main
// file. Macros have their own FileID so this also checks if locations are not
// within the macros.
if ((Begin.first != SM.getMainFileID()) || (End.first != SM.getMainFileID()))
return llvm::None;
FoldingRange Range;
Range.startCharacter = SM.getColumnNumber(Begin.first, Begin.second) - 1;
Range.startLine = SM.getLineNumber(Begin.first, Begin.second) - 1;
Range.endCharacter = SM.getColumnNumber(End.first, End.second) - 1;
Range.endLine = SM.getLineNumber(End.first, End.second) - 1;
return Range;
}
llvm::Optional<FoldingRange> extractFoldingRange(const syntax::Node *Node,
const SourceManager &SM) {
if (const auto *Stmt = dyn_cast<syntax::CompoundStatement>(Node)) {
const auto *LBrace = cast_or_null<syntax::Leaf>(
Stmt->findChild(syntax::NodeRole::OpenParen));
// FIXME(kirillbobyrev): This should find the last child. Compound
// statements have only one pair of braces so this is valid but for other
// node kinds it might not be correct.
const auto *RBrace = cast_or_null<syntax::Leaf>(
Stmt->findChild(syntax::NodeRole::CloseParen));
if (!LBrace || !RBrace)
return llvm::None;
// Fold the entire range within braces, including whitespace.
const SourceLocation LBraceLocInfo = LBrace->getToken()->endLocation(),
RBraceLocInfo = RBrace->getToken()->location();
auto Range = toFoldingRange(SourceRange(LBraceLocInfo, RBraceLocInfo), SM);
// Do not generate folding range for compound statements without any
// nodes and newlines.
if (Range && Range->startLine != Range->endLine)
return Range;
}
return llvm::None;
}
// Traverse the tree and collect folding ranges along the way.
std::vector<FoldingRange> collectFoldingRanges(const syntax::Node *Root,
const SourceManager &SM) {
std::queue<const syntax::Node *> Nodes;
Nodes.push(Root);
std::vector<FoldingRange> Result;
while (!Nodes.empty()) {
const syntax::Node *Node = Nodes.front();
Nodes.pop();
const auto Range = extractFoldingRange(Node, SM);
if (Range)
Result.push_back(*Range);
if (const auto *T = dyn_cast<syntax::Tree>(Node))
for (const auto *NextNode = T->getFirstChild(); NextNode;
NextNode = NextNode->getNextSibling())
Nodes.push(NextNode);
}
return Result;
}
} // namespace
llvm::Expected<SelectionRange> getSemanticRanges(ParsedAST &AST, Position Pos) {
std::vector<Range> Ranges;
const auto &SM = AST.getSourceManager();
const auto &LangOpts = AST.getLangOpts();
auto FID = SM.getMainFileID();
auto Offset = positionToOffset(SM.getBufferData(FID), Pos);
if (!Offset) {
return Offset.takeError();
}
// Get node under the cursor.
SelectionTree ST = SelectionTree::createRight(
AST.getASTContext(), AST.getTokens(), *Offset, *Offset);
for (const auto *Node = ST.commonAncestor(); Node != nullptr;
Node = Node->Parent) {
if (const Decl *D = Node->ASTNode.get<Decl>()) {
if (llvm::isa<TranslationUnitDecl>(D)) {
break;
}
}
auto SR = toHalfOpenFileRange(SM, LangOpts, Node->ASTNode.getSourceRange());
if (!SR.hasValue() || SM.getFileID(SR->getBegin()) != SM.getMainFileID()) {
continue;
}
Range R;
R.start = sourceLocToPosition(SM, SR->getBegin());
R.end = sourceLocToPosition(SM, SR->getEnd());
addIfDistinct(R, Ranges);
}
if (Ranges.empty()) {
// LSP provides no way to signal "the point is not within a semantic range".
// Return an empty range at the point.
SelectionRange Empty;
Empty.range.start = Empty.range.end = Pos;
return std::move(Empty);
}
// Convert to the LSP linked-list representation.
SelectionRange Head;
Head.range = std::move(Ranges.front());
SelectionRange *Tail = &Head;
for (auto &Range :
llvm::makeMutableArrayRef(Ranges.data(), Ranges.size()).drop_front()) {
Tail->parent = std::make_unique<SelectionRange>();
Tail = Tail->parent.get();
Tail->range = std::move(Range);
}
return std::move(Head);
}
// FIXME(kirillbobyrev): Collect comments, PP conditional regions, includes and
// other code regions (e.g. public/private/protected sections of classes,
// control flow statement bodies).
// Related issue: https://github.com/clangd/clangd/issues/310
llvm::Expected<std::vector<FoldingRange>> getFoldingRanges(ParsedAST &AST) {
syntax::Arena A(AST.getSourceManager(), AST.getLangOpts(), AST.getTokens());
const auto *SyntaxTree = syntax::buildSyntaxTree(A, AST.getASTContext());
return collectFoldingRanges(SyntaxTree, AST.getSourceManager());
}
} // namespace clangd
} // namespace clang
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