[clang] [clang-format] Add BreakBinaryOperations configuration (PR #95013)

[Owen Pan via cfe-commits]

================
@@ -146,6 +147,33 @@ static bool startsNextParameter(const FormatToken &Current,
            Style.BreakInheritanceList != FormatStyle::BILS_BeforeComma));
 }
 
+// Returns \c true if \c Token in an alignable binary operator
+static bool isAlignableBinaryOperator(const FormatToken &Token) {
+  // No need to align binary operators that only have two operands.
+  bool HasTwoOperands = Token.OperatorIndex == 0 && !Token.NextOperator &&
+                        Token.isNot(TT_ConditionalExpr);
+  return Token.is(TT_BinaryOperator) && !HasTwoOperands &&
+         Token.getPrecedence() > prec::Conditional &&
+         Token.getPrecedence() < prec::PointerToMember;
+}
+
+// Returns \c true if \c Current starts the next operand in a binary operation.
+static bool startsNextOperand(const FormatToken &Current) {
+  assert(Current.Previous);
+  const auto &Previous = *Current.Previous;
+  return isAlignableBinaryOperator(Previous) && !Current.isTrailingComment();
+}
+
+// Returns \c true if \c Current is a binary operation that must break.
+static bool mustBreakBinaryOperation(const FormatToken &Current,
+                                     const FormatStyle &Style) {
+  return Style.BreakBinaryOperations != FormatStyle::BBO_Never &&
+         ((isAlignableBinaryOperator(Current) &&
+           Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None) ||
+          (startsNextOperand(Current) &&
+           Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None));
----------------
owenca wrote:

```suggestion
         (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None
              ? startsNextOperand
              : isAlignableBinaryOperator)(Current);
```

https://github.com/llvm/llvm-project/pull/95013