Improve formatting of chained calls.

clang-format already prevented sequences like:
  ...
  SomeParameter).someFunction(
  ...

as those are quite confusing. This failed on:
  ...
  SomeParameter).someFunction(otherFunction(
  ...

Fixed in this patch.

llvm-svn: 177157

clang/lib/Format/Format.cpp

@@ -985,14 +985,6 @@ private:
         !(State.NextToken->is(tok::r_brace) &&
           State.Stack.back().BreakBeforeClosingBrace))
       return false;
-    // This prevents breaks like:
-    //   ...
-    //   SomeParameter, OtherParameter).DoSomething(
-    //   ...
-    // As they hide "DoSomething" and generally bad for readability.
-    if (State.NextToken->Parent->is(tok::l_paren) &&
-        State.ParenLevel <= State.StartOfLineLevel)
-      return false;
     // Trying to insert a parameter on a new line if there are already more than
     // one parameter on the current line is bin packing.
     if (State.Stack.back().HasMultiParameterLine &&
@@ -1031,9 +1023,25 @@ private:
       return true;
     if (State.NextToken->Type == TT_InlineASMColon)
       return true;
+    // This prevents breaks like:
+    //   ...
+    //   SomeParameter, OtherParameter).DoSomething(
+    //   ...
+    // As they hide "DoSomething" and generally bad for readability.
+    if (State.NextToken->isOneOf(tok::period, tok::arrow) &&
+        getRemainingLength(State) + State.Column > getColumnLimit() &&
+        State.ParenLevel < State.StartOfLineLevel)
+      return true;
     return false;
   }
 
+  // Returns the total number of columns required for the remaining tokens.
+  unsigned getRemainingLength(const LineState &State) {
+    if (State.NextToken && State.NextToken->Parent)
+      return Line.Last->TotalLength - State.NextToken->Parent->TotalLength;
+    return 0;
+  }
+
   FormatStyle Style;
   SourceManager &SourceMgr;
   const AnnotatedLine &Line;

clang/unittests/Format/FormatTest.cpp

@@ -1720,6 +1720,12 @@ TEST_F(FormatTest, WrapsAtFunctionCallsIfNecessary) {
                "    .WillRepeatedly(Return(SomeValue));");
   verifyFormat("SomeMap[std::pair(aaaaaaaaaaaa, bbbbbbbbbbbbbbb)]\n"
                "    .insert(ccccccccccccccccccccccc);");
+  verifyFormat(
+      "aaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+      "      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa)\n"
+      "    .aaaaaaaaaaaaaaa(\n"
+      "        aa(aaaaaaaaaaaaaaaaaaaaaaaaaaa, aaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+      "           aaaaaaaaaaaaaaaaaaaaaaaaaaa));");
 
   // Here, it is not necessary to wrap at "." or "->".
   verifyFormat("if (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaa) ||\n"
@@ -1737,6 +1743,10 @@ TEST_F(FormatTest, WrapsAtFunctionCallsIfNecessary) {
   verifyFormat("a->aaaaaa()->aaaaaaaaaaa(aaaaaaaa()->aaaaaa()->aaaaa() ||\n"
                "                         aaaaaaaaa()->aaaaaa()->aaaaa());");
 
+  // FIXME: Should we break before .a()?
+  verifyFormat("aaaaa(aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa,\n"
+               "      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa).a();");
+
   FormatStyle NoBinPacking = getLLVMStyle();
   NoBinPacking.BinPackParameters = false;
   verifyFormat("aaaaaaaaaaaaaaaaaaaaaa(aaaaaaaaaaaaaaaaaaaaa)\n"