Initial version of formatting library.

This formatting library will be used by a stand-alone clang-format tool
and can also be used when writing other refactorings.

Manuel's original design document:
https://docs.google.com/a/google.com/document/d/1gpckL2U_6QuU9YW2L1ABsc4Fcogn5UngKk7fE5dDOoA/edit

The library can already successfully format itself.

Review: http://llvm-reviews.chandlerc.com/D80

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169137 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 119 insertions, 0 deletions

diff --git a/lib/Format/UnwrappedLineParser.h b/lib/Format/UnwrappedLineParser.h
new file mode 100644
index 0000000000..1e6899e092
--- /dev/null
+++ b/lib/Format/UnwrappedLineParser.h
@@ -0,0 +1,119 @@
+//===--- UnwrappedLineParser.cpp - Format C++ code ------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file contains the declaration of the UnwrappedLineParser,
+/// which turns a stream of tokens into UnwrappedLines.
+///
+/// This is EXPERIMENTAL code under heavy development. It is not in a state yet,
+/// where it can be used to format real code.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
+#define LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H
+
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/IdentifierTable.h"
+#include "clang/Lex/Lexer.h"
+
+namespace clang {
+namespace format {
+
+/// \brief A wrapper around a \c Token storing information about the
+/// whitespace characters preceeding it.
+struct FormatToken {
+  FormatToken() : NewlinesBefore(0), WhiteSpaceLength(0) {
+  }
+
+  /// \brief The \c Token.
+  Token Tok;
+
+  /// \brief The number of newlines immediately before the \c Token.
+  ///
+  /// This can be used to determine what the user wrote in the original code
+  /// and thereby e.g. leave an empty line between two function definitions.
+  unsigned NewlinesBefore;
+
+  /// \brief The location of the start of the whitespace immediately preceeding
+  /// the \c Token.
+  ///
+  /// Used together with \c WhiteSpaceLength to create a \c Replacement.
+  SourceLocation WhiteSpaceStart;
+
+  /// \brief The length in characters of the whitespace immediately preceeding
+  /// the \c Token.
+  unsigned WhiteSpaceLength;
+};
+
+/// \brief An unwrapped line is a sequence of \c Token, that we would like to
+/// put on a single line if there was no column limit.
+///
+/// This is used as a main interface between the \c UnwrappedLineParser and the
+/// \c UnwrappedLineFormatter. The key property is that changing the formatting
+/// within an unwrapped line does not affect any other unwrapped lines.
+struct UnwrappedLine {
+  UnwrappedLine() : Level(0) {
+  }
+
+  /// \brief The \c Token comprising this \c UnwrappedLine.
+  SmallVector<FormatToken, 16> Tokens;
+
+  /// \brief The indent level of the \c UnwrappedLine.
+  unsigned Level;
+};
+
+class UnwrappedLineConsumer {
+public:
+  virtual void formatUnwrappedLine(const UnwrappedLine &Line) = 0;
+};
+
+class UnwrappedLineParser {
+public:
+  UnwrappedLineParser(Lexer &Lex, SourceManager &SourceMgr,
+                      UnwrappedLineConsumer &Callback);
+
+  void parse();
+
+private:
+  void parseLevel();
+  void parseBlock();
+  void parsePPDirective();
+  void parseComment();
+  void parseStatement();
+  void parseParens();
+  void parseIfThenElse();
+  void parseDoWhile();
+  void parseLabel();
+  void parseCaseLabel();
+  void parseSwitch();
+  void parseAccessSpecifier();
+  void parseEnum();
+  void addUnwrappedLine();
+  bool eof() const;
+  void nextToken();
+  void parseToken();
+
+  /// Returns the text of \c FormatTok.
+  StringRef tokenText();
+
+  UnwrappedLine Line;
+  FormatToken FormatTok;
+  bool GreaterStashed;
+
+  Lexer &Lex;
+  SourceManager &SourceMgr;
+  IdentifierTable IdentTable;
+  UnwrappedLineConsumer &Callback;
+};
+
+}  // end namespace format
+}  // end namespace clang
+
+#endif // LLVM_CLANG_FORMAT_UNWRAPPED_LINE_PARSER_H