Restore .h files after clearing the cache.

Author: cmtice

lldb/include/lldb/ValueObject/DILLexer.h

@@ -0,0 +1,127 @@
+//===-- DILLexer.h ----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_VALUEOBJECT_DILLEXER_H
+#define LLDB_VALUEOBJECT_DILLEXER_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+#include <cstdint>
+#include <limits.h>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace lldb_private::dil {
+
+/// Class defining the tokens generated by the DIL lexer and used by the
+/// DIL parser.
+class Token {
+public:
+  enum Kind {
+    coloncolon,
+    eof,
+    identifier,
+    l_paren,
+    r_paren,
+  };
+
+  Token(Kind kind, std::string spelling, uint32_t start)
+      : m_kind(kind), m_spelling(std::move(spelling)), m_start_pos(start) {}
+
+  Kind GetKind() const { return m_kind; }
+
+  std::string GetSpelling() const { return m_spelling; }
+
+  bool Is(Kind kind) const { return m_kind == kind; }
+
+  bool IsNot(Kind kind) const { return m_kind != kind; }
+
+  bool IsOneOf(Kind kind1, Kind kind2) const { return Is(kind1) || Is(kind2); }
+
+  template <typename... Ts> bool IsOneOf(Kind kind, Ts... Ks) const {
+    return Is(kind) || IsOneOf(Ks...);
+  }
+
+  uint32_t GetLocation() const { return m_start_pos; }
+
+  static llvm::StringRef GetTokenName(Kind kind);
+
+private:
+  Kind m_kind;
+  std::string m_spelling;
+  uint32_t m_start_pos; // within entire expression string
+};
+
+/// Class for doing the simple lexing required by DIL.
+class DILLexer {
+public:
+  /// Lexes all the tokens in expr and calls the private constructor
+  /// with the lexed tokens.
+  static llvm::Expected<DILLexer> Create(llvm::StringRef expr);
+
+  /// Return the current token to be handled by the DIL parser.
+  const Token &GetCurrentToken() { return m_lexed_tokens[m_tokens_idx]; }
+
+  /// Advance the current token position by N.
+  void Advance(uint32_t N = 1) {
+    if (m_tokens_idx + N >= m_lexed_tokens.size())
+      // N is too large; advance to the end of the lexed tokens.
+      m_tokens_idx = m_lexed_tokens.size() - 1;
+    else
+      m_tokens_idx += N;
+  }
+
+  /// Return the lexed token N positions ahead of the 'current' token
+  /// being handled by the DIL parser.
+  const Token &LookAhead(uint32_t N) {
+    if (m_tokens_idx + N < m_lexed_tokens.size())
+      return m_lexed_tokens[m_tokens_idx + N];
+
+    // Last token should be an 'eof' token.
+    return m_lexed_tokens.back();
+  }
+
+  /// Return the index for the 'current' token being handled by the DIL parser.
+  uint32_t GetCurrentTokenIdx() { return m_tokens_idx; }
+
+  /// Set the index for the 'current' token (to be handled by the parser)
+  /// to a particular position. Used for either committing 'look ahead' parsing
+  /// or rolling back tentative parsing.
+  void ResetTokenIdx(uint32_t new_value) {
+    assert(new_value < m_lexed_tokens.size());
+    m_tokens_idx = new_value;
+  }
+
+  uint32_t NumLexedTokens() { return m_lexed_tokens.size(); }
+
+private:
+  DILLexer(llvm::StringRef dil_expr, std::vector<Token> lexed_tokens)
+      : m_expr(dil_expr), m_lexed_tokens(std::move(lexed_tokens)),
+        m_tokens_idx(0), m_eof_token(Token(Token::eof, "", 0)) {}
+
+  static llvm::Expected<Token> Lex(llvm::StringRef expr,
+                                   llvm::StringRef &remainder);
+
+  // The input string we are lexing & parsing.
+  llvm::StringRef m_expr;
+
+  // Holds all of the tokens lexed so far.
+  std::vector<Token> m_lexed_tokens;
+
+  // Index into m_lexed_tokens; indicates which token the DIL parser is
+  // currently trying to parse/handle.
+  uint32_t m_tokens_idx;
+
+  // "eof" token; to be returned by lexer when 'look ahead' fails.
+  Token m_eof_token;
+};
+
+} // namespace lldb_private::dil
+
+#endif // LLDB_VALUEOBJECT_DILLEXER_H