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| //===--- CodeCompletionStrings.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 "CodeCompletionStrings.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/RawCommentList.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Sema/CodeCompleteConsumer.h"
#include <limits>
#include <utility>
namespace clang {
namespace clangd {
namespace {
bool isInformativeQualifierChunk(CodeCompletionString::Chunk const &Chunk) {
return Chunk.Kind == CodeCompletionString::CK_Informative &&
llvm::StringRef(Chunk.Text).endswith("::");
}
void appendEscapeSnippet(const llvm::StringRef Text, std::string *Out) {
for (const auto Character : Text) {
if (Character == '$' || Character == '}' || Character == '\\')
Out->push_back('\\');
Out->push_back(Character);
}
}
void appendOptionalChunk(const CodeCompletionString &CCS, std::string *Out) {
for (const CodeCompletionString::Chunk &C : CCS) {
switch (C.Kind) {
case CodeCompletionString::CK_Optional:
assert(C.Optional &&
"Expected the optional code completion string to be non-null.");
appendOptionalChunk(*C.Optional, Out);
break;
default:
*Out += C.Text;
break;
}
}
}
bool looksLikeDocComment(llvm::StringRef CommentText) {
// We don't report comments that only contain "special" chars.
// This avoids reporting various delimiters, like:
// =================
// -----------------
// *****************
return CommentText.find_first_not_of("/*-= \t\r\n") != llvm::StringRef::npos;
}
} // namespace
std::string getDocComment(const ASTContext &Ctx,
const CodeCompletionResult &Result,
bool CommentsFromHeaders) {
// FIXME: clang's completion also returns documentation for RK_Pattern if they
// contain a pattern for ObjC properties. Unfortunately, there is no API to
// get this declaration, so we don't show documentation in that case.
if (Result.Kind != CodeCompletionResult::RK_Declaration)
return "";
return Result.getDeclaration() ? getDeclComment(Ctx, *Result.getDeclaration())
: "";
}
std::string getDeclComment(const ASTContext &Ctx, const NamedDecl &Decl) {
if (isa<NamespaceDecl>(Decl)) {
// Namespaces often have too many redecls for any particular redecl comment
// to be useful. Moreover, we often confuse file headers or generated
// comments with namespace comments. Therefore we choose to just ignore
// the comments for namespaces.
return "";
}
const RawComment *RC = getCompletionComment(Ctx, &Decl);
if (!RC)
return "";
// Sanity check that the comment does not come from the PCH. We choose to not
// write them into PCH, because they are racy and slow to load.
assert(!Ctx.getSourceManager().isLoadedSourceLocation(RC->getBeginLoc()));
std::string Doc =
RC->getFormattedText(Ctx.getSourceManager(), Ctx.getDiagnostics());
return looksLikeDocComment(Doc) ? Doc : "";
}
void getSignature(const CodeCompletionString &CCS, std::string *Signature,
std::string *Snippet, std::string *RequiredQualifiers,
bool CompletingPattern) {
// Placeholder with this index will be ${0:…} to mark final cursor position.
// Usually we do not add $0, so the cursor is placed at end of completed text.
unsigned CursorSnippetArg = std::numeric_limits<unsigned>::max();
if (CompletingPattern) {
// In patterns, it's best to place the cursor at the last placeholder, to
// handle cases like
// namespace ${1:name} {
// ${0:decls}
// }
CursorSnippetArg =
llvm::count_if(CCS, [](const CodeCompletionString::Chunk &C) {
return C.Kind == CodeCompletionString::CK_Placeholder;
});
}
unsigned SnippetArg = 0;
bool HadObjCArguments = false;
for (const auto &Chunk : CCS) {
// Informative qualifier chunks only clutter completion results, skip
// them.
if (isInformativeQualifierChunk(Chunk))
continue;
switch (Chunk.Kind) {
case CodeCompletionString::CK_TypedText:
// The typed-text chunk is the actual name. We don't record this chunk.
// C++:
// In general our string looks like <qualifiers><name><signature>.
// So once we see the name, any text we recorded so far should be
// reclassified as qualifiers.
//
// Objective-C:
// Objective-C methods may have multiple typed-text chunks, so we must
// treat them carefully. For Objective-C methods, all typed-text chunks
// will end in ':' (unless there are no arguments, in which case we
// can safely treat them as C++).
if (!llvm::StringRef(Chunk.Text).endswith(":")) { // Treat as C++.
if (RequiredQualifiers)
*RequiredQualifiers = std::move(*Signature);
Signature->clear();
Snippet->clear();
} else { // Objective-C method with args.
// If this is the first TypedText to the Objective-C method, discard any
// text that we've previously seen (such as previous parameter selector,
// which will be marked as Informative text).
//
// TODO: Make previous parameters part of the signature for Objective-C
// methods.
if (!HadObjCArguments) {
HadObjCArguments = true;
Signature->clear();
} else { // Subsequent argument, considered part of snippet/signature.
*Signature += Chunk.Text;
*Snippet += Chunk.Text;
}
}
break;
case CodeCompletionString::CK_Text:
*Signature += Chunk.Text;
*Snippet += Chunk.Text;
break;
case CodeCompletionString::CK_Optional:
assert(Chunk.Optional);
// No need to create placeholders for default arguments in Snippet.
appendOptionalChunk(*Chunk.Optional, Signature);
break;
case CodeCompletionString::CK_Placeholder:
*Signature += Chunk.Text;
++SnippetArg;
*Snippet +=
"${" +
std::to_string(SnippetArg == CursorSnippetArg ? 0 : SnippetArg) + ':';
appendEscapeSnippet(Chunk.Text, Snippet);
*Snippet += '}';
break;
case CodeCompletionString::CK_Informative:
// For example, the word "const" for a const method, or the name of
// the base class for methods that are part of the base class.
*Signature += Chunk.Text;
// Don't put the informative chunks in the snippet.
break;
case CodeCompletionString::CK_ResultType:
// This is not part of the signature.
break;
case CodeCompletionString::CK_CurrentParameter:
// This should never be present while collecting completion items,
// only while collecting overload candidates.
llvm_unreachable("Unexpected CK_CurrentParameter while collecting "
"CompletionItems");
break;
case CodeCompletionString::CK_LeftParen:
case CodeCompletionString::CK_RightParen:
case CodeCompletionString::CK_LeftBracket:
case CodeCompletionString::CK_RightBracket:
case CodeCompletionString::CK_LeftBrace:
case CodeCompletionString::CK_RightBrace:
case CodeCompletionString::CK_LeftAngle:
case CodeCompletionString::CK_RightAngle:
case CodeCompletionString::CK_Comma:
case CodeCompletionString::CK_Colon:
case CodeCompletionString::CK_SemiColon:
case CodeCompletionString::CK_Equal:
case CodeCompletionString::CK_HorizontalSpace:
*Signature += Chunk.Text;
*Snippet += Chunk.Text;
break;
case CodeCompletionString::CK_VerticalSpace:
*Snippet += Chunk.Text;
// Don't even add a space to the signature.
break;
}
}
}
std::string formatDocumentation(const CodeCompletionString &CCS,
llvm::StringRef DocComment) {
// Things like __attribute__((nonnull(1,3))) and [[noreturn]]. Present this
// information in the documentation field.
std::string Result;
const unsigned AnnotationCount = CCS.getAnnotationCount();
if (AnnotationCount > 0) {
Result += "Annotation";
if (AnnotationCount == 1) {
Result += ": ";
} else /* AnnotationCount > 1 */ {
Result += "s: ";
}
for (unsigned I = 0; I < AnnotationCount; ++I) {
Result += CCS.getAnnotation(I);
Result.push_back(I == AnnotationCount - 1 ? '\n' : ' ');
}
}
// Add brief documentation (if there is any).
if (!DocComment.empty()) {
if (!Result.empty()) {
// This means we previously added annotations. Add an extra newline
// character to make the annotations stand out.
Result.push_back('\n');
}
Result += DocComment;
}
return Result;
}
std::string getReturnType(const CodeCompletionString &CCS) {
for (const auto &Chunk : CCS)
if (Chunk.Kind == CodeCompletionString::CK_ResultType)
return Chunk.Text;
return "";
}
} // namespace clangd
} // namespace clang
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