[clang-format][NFC] Clean up IndentForLevel in LevelIndentTracker

[HazardyKnusperkeks]

clang/lib/Format/UnwrappedLineFormatter.cpp

82–83

Could we do this with with resize similar to my proposal in D129064?

[owenpan]

Use resize() instead of insert().

[owenpan]

clang/lib/Format/UnwrappedLineFormatter.cpp

82–83

Good idea!

clang/lib/Format/UnwrappedLineFormatter.cpp

public:
   unsigned getIndent() const { return Indent; }
 
   /// Update the indent state given that \p Line is going to be formatted
   /// next.
   void nextLine(const AnnotatedLine &Line) {
     Offset = getIndentOffset(*Line.First);
     // Update the indent level cache size so that we can rely on it
     // having the right size in adjustToUnmodifiedline.
-    while (IndentForLevel.size() <= Line.Level)
-      IndentForLevel.push_back(-1);
+    skipLine(Line, /*UnknownIndent=*/true);
     if (Line.InPPDirective) {
       unsigned IndentWidth =
           (Style.PPIndentWidth >= 0) ? Style.PPIndentWidth : Style.IndentWidth;
       Indent = Line.Level * IndentWidth + AdditionalIndent;
     } else {
       IndentForLevel.resize(Line.Level + 1);
       Indent = getIndent(Line.Level);
     }
     if (static_cast<int>(Indent) + Offset >= 0)
       Indent += Offset;
     if (Line.First->is(TT_CSharpGenericTypeConstraint))
       Indent = Line.Level * Style.IndentWidth + Style.ContinuationIndentWidth;
   }
 
   /// Update the indent state given that \p Line indent should be
   /// skipped.
-  void skipLine(const AnnotatedLine &Line) {
-    while (IndentForLevel.size() <= Line.Level)
-      IndentForLevel.push_back(Indent);
+  void skipLine(const AnnotatedLine &Line, bool UnknownIndent = false) {
+    const auto Size = IndentForLevel.size();
+    if (Size <= Line.Level)
+      IndentForLevel.insert(IndentForLevel.end(), Line.Level - Size + 1,
+                            UnknownIndent ? -1 : Indent);
   }
 
   /// Update the level indent to adapt to the given \p Line.
   ///
   /// When a line is not formatted, we move the subsequent lines on the same
   /// level to the same indent.
   /// Note that \c nextLine must have been called before this method.
   void adjustToUnmodifiedLine(const AnnotatedLine &Line) {
unsigned getIndent(unsigned Level) const {
     return getIndent(Level - 1) + Style.IndentWidth;
   }
 
   const FormatStyle &Style;
   const AdditionalKeywords &Keywords;
   const unsigned AdditionalIndent;
 
   /// The indent in characters for each level.
-  std::vector<int> IndentForLevel;
+  SmallVector<int> IndentForLevel;
 
   /// Offset of the current line relative to the indent level.
   ///
   /// For example, the 'public' keywords is often indented with a negative
   /// offset.
   int Offset = 0;
 
   /// The current line's indent.