replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

[clang-format] tweaked another case of lambda formatting 

Summary:
This is done in order to improve cases where the lambda's body is moved too far to the right. Consider the following snippet with column limit set to 79:

```
void f() {
  leader::MakeThisCallHere(&leader_service_,
                           cq_.get(),
                           [this, liveness](const leader::ReadRecordReq& req,
                                            std::function<void()> done) {
                             logger_->HandleReadRecord(
                                 req, resp, std::move(done));
                           });

  leader::MakeAnother(&leader_service_,
                      cq_.get(),
                      [this, liveness](const leader::ReadRecordReq& req,
                                       std::function<void()> done) {
                        logger_->HandleReadRecord(
                            req, resp, std::move(done), a);
                      });
}
```

The tool favors extra indentation for the lambda body and so the code incurs extra wrapping and adjacent calls are indented to a different level. I find this behavior annoying and I'd like the tool to favor new lines and, thus, use the extra width.

The fix, reduced, brings the following formatting.

Before:

    function(1,
             [] {
               DoStuff();
               //
             },
             1);

After:

    function(
        1,
        [] {
          DoStuff();
          //
        },
        1);

Refer to the new tests in FormatTest.cpp

Contributed by oleg.smolsky!

Reviewers: djasper, klimek, krasimir

Subscribers: cfe-commits, owenpan

Tags: #clang

Differential Revision: https://reviews.llvm.org/D52676

llvm-svn: 345753
This commit is contained in:
Krasimir Georgiev 2018-10-31 17:56:57 +00:00
parent 5bcec66c55
commit 5528cace04
5 changed files with 122 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
clang/lib/Format/ContinuationIndenter.cpp
View File

@ -1135,7 +1135,8 @@ unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
// }, a, b, c);
if (Current.isNot(tok::comment) && Previous &&
Previous->isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) &&
!Previous->is(TT_DictLiteral) && State.Stack.size() > 1) {
!Previous->is(TT_DictLiteral) && State.Stack.size() > 1 &&
!State.Stack.back().HasMultipleNestedBlocks) {
if (State.Stack[State.Stack.size() - 2].NestedBlockInlined && Newline)
for (unsigned i = 0, e = State.Stack.size() - 1; i != e; ++i)
State.Stack[i].NoLineBreak = true;

8
clang/lib/Format/FormatToken.h
View File

@ -599,6 +599,8 @@ public:
/// Notifies the \c Role that a comma was found.
virtual void CommaFound(const FormatToken *Token) {}
virtual const FormatToken *lastComma() { return nullptr; }
protected:
const FormatStyle &Style;
};
@ -621,6 +623,12 @@ public:
Commas.push_back(Token);
}
const FormatToken *lastComma() override {
if (Commas.empty())
return nullptr;
return Commas.back();
}
private:
/// A struct that holds information on how to format a given list with
/// a specific number of columns.

24
clang/lib/Format/TokenAnnotator.cpp
View File

@ -3049,6 +3049,30 @@ bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
return true;
}
// Deal with lambda arguments in C++ - we want consistent line breaks whether
// they happen to be at arg0, arg1 or argN. The selection is a bit nuanced
// as aggressive line breaks are placed when the lambda is not the last arg.
if ((Style.Language == FormatStyle::LK_Cpp ||
Style.Language == FormatStyle::LK_ObjC) &&
Left.is(tok::l_paren) && Left.BlockParameterCount > 0 &&
!Right.isOneOf(tok::l_paren, TT_LambdaLSquare)) {
// Multiple lambdas in the same function call force line breaks.
if (Left.BlockParameterCount > 1)
return true;
// A lambda followed by another arg forces a line break.
if (!Left.Role)
return false;
auto Comma = Left.Role->lastComma();
if (!Comma)
return false;
auto Next = Comma->getNextNonComment();
if (!Next)
return false;
if (!Next->isOneOf(TT_LambdaLSquare, tok::l_brace, tok::caret))
return true;
}
return false;
}

7
clang/lib/Format/UnwrappedLineFormatter.cpp
View File

@ -988,8 +988,7 @@ private:
Path.push_front(Best);
Best = Best->Previous;
}
for (std::deque<StateNode *>::iterator I = Path.begin(), E = Path.end();
I != E; ++I) {
for (auto I = Path.begin(), E = Path.end(); I != E; ++I) {
unsigned Penalty = 0;
formatChildren(State, (*I)->NewLine, /*DryRun=*/false, Penalty);
Penalty += Indenter->addTokenToState(State, (*I)->NewLine, false);
@ -998,8 +997,8 @@ private:
printLineState((*I)->Previous->State);
if ((*I)->NewLine) {
llvm::dbgs() << "Penalty for placing "
<< (*I)->Previous->State.NextToken->Tok.getName() << ": "
<< Penalty << "\n";
<< (*I)->Previous->State.NextToken->Tok.getName()
<< " on a new line: " << Penalty << "\n";
}
});
}

98
clang/unittests/Format/FormatTest.cpp
View File

@ -3277,11 +3277,12 @@ TEST_F(FormatTest, LayoutNestedBlocks) {
"});");
FormatStyle Style = getGoogleStyle();
Style.ColumnLimit = 45;
verifyFormat("Debug(aaaaa,\n"
" {\n"
" if (aaaaaaaaaaaaaaaaaaaaaaaa) return;\n"
" },\n"
" a);",
verifyFormat("Debug(\n"
" aaaaa,\n"
" {\n"
" if (aaaaaaaaaaaaaaaaaaaaaaaa) return;\n"
" },\n"
" a);",
Style);
verifyFormat("SomeFunction({MACRO({ return output; }), b});");
@ -11739,6 +11740,18 @@ TEST_F(FormatTest, FormatsLambdas) {
" x.end(), //\n"
" [&](int, int) { return 1; });\n"
"}\n");
verifyFormat("void f() {\n"
" other.other.other.other.other(\n"
" x.begin(), x.end(),\n"
" [something, rather](int, int, int, int, int, int, int) { return 1; });\n"
"}\n");
verifyFormat("void f() {\n"
" other.other.other.other.other(\n"
" x.begin(), x.end(),\n"
" [something, rather](int, int, int, int, int, int, int) {\n"
" //\n"
" });\n"
"}\n");
verifyFormat("SomeFunction([]() { // A cool function...\n"
" return 43;\n"
"});");
@ -11790,9 +11803,9 @@ TEST_F(FormatTest, FormatsLambdas) {
verifyFormat("SomeFunction({[&] {\n"
" // comment\n"
"}});");
verifyFormat("virtual aaaaaaaaaaaaaaaa(std::function<bool()> bbbbbbbbbbbb =\n"
" [&]() { return true; },\n"
" aaaaa aaaaaaaaa);");
verifyFormat("virtual aaaaaaaaaaaaaaaa(\n"
" std::function<bool()> bbbbbbbbbbbb = [&]() { return true; },\n"
" aaaaa aaaaaaaaa);");
// Lambdas with return types.
verifyFormat("int c = []() -> int { return 2; }();\n");
@ -11819,17 +11832,76 @@ TEST_F(FormatTest, FormatsLambdas) {
" return 1; //\n"
"};");
// Multiple lambdas in the same parentheses change indentation rules.
// Multiple lambdas in the same parentheses change indentation rules. These
// lambdas are forced to start on new lines.
verifyFormat("SomeFunction(\n"
" []() {\n"
" int i = 42;\n"
" return i;\n"
" //\n"
" },\n"
" []() {\n"
" int j = 43;\n"
" return j;\n"
" //\n"
" });");
// A lambda passed as arg0 is always pushed to the next line.
verifyFormat("SomeFunction(\n"
" [this] {\n"
" //\n"
" },\n"
" 1);\n");
// A multi-line lambda passed as arg1 forces arg0 to be pushed out, just like the arg0
// case above.
auto Style = getGoogleStyle();
Style.BinPackArguments = false;
verifyFormat("SomeFunction(\n"
" a,\n"
" [this] {\n"
" //\n"
" },\n"
" b);\n",
Style);
verifyFormat("SomeFunction(\n"
" a,\n"
" [this] {\n"
" //\n"
" },\n"
" b);\n");
// A lambda with a very long line forces arg0 to be pushed out irrespective of
// the BinPackArguments value (as long as the code is wide enough).
verifyFormat("something->SomeFunction(\n"
" a,\n"
" [this] {\n"
" D0000000000000000000000000000000000000000000000000000000000001();\n"
" },\n"
" b);\n");
// A multi-line lambda is pulled up as long as the introducer fits on the previous
// line and there are no further args.
verifyFormat("function(1, [this, that] {\n"
" //\n"
"});\n");
verifyFormat("function([this, that] {\n"
" //\n"
"});\n");
// FIXME: this format is not ideal and we should consider forcing the first arg
// onto its own line.
verifyFormat("function(a, b, c, //\n"
" d, [this, that] {\n"
" //\n"
" });\n");
// Multiple lambdas are treated correctly even when there is a short arg0.
verifyFormat("SomeFunction(\n"
" 1,\n"
" [this] {\n"
" //\n"
" },\n"
" [this] {\n"
" //\n"
" },\n"
" 1);\n");
// More complex introducers.
verifyFormat("return [i, args...] {};");