Copy irregexp related code from V8.

runtime/vm/regexp_parser.h

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_REGEXP_PARSER_H_
+#define VM_REGEXP_PARSER_H_
+
+// SNIP
+
+namespace dart {
+
+// SNIP
+
+// Accumulates RegExp atoms and assertions into lists of terms and alternatives.
+class RegExpBuilder: public ZoneObject {
+ public:
+  explicit RegExpBuilder(Zone* zone);
+  void AddCharacter(uc16 character);
+  // "Adds" an empty expression. Does nothing except consume a
+  // following quantifier
+  void AddEmpty();
+  void AddAtom(RegExpTree* tree);
+  void AddAssertion(RegExpTree* tree);
+  void NewAlternative();  // '|'
+  void AddQuantifierToAtom(
+      int min, int max, RegExpQuantifier::QuantifierType type);
+  RegExpTree* ToRegExp();
+
+ private:
+  void FlushCharacters();
+  void FlushText();
+  void FlushTerms();
+  Zone* zone() const { return zone_; }
+
+  Zone* zone_;
+  bool pending_empty_;
+  ZoneList<uc16>* characters_;
+  BufferedZoneList<RegExpTree, 2> terms_;
+  BufferedZoneList<RegExpTree, 2> text_;
+  BufferedZoneList<RegExpTree, 2> alternatives_;
+#ifdef DEBUG
+  enum {ADD_NONE, ADD_CHAR, ADD_TERM, ADD_ASSERT, ADD_ATOM} last_added_;
+#define LAST(x) last_added_ = x;
+#else
+#define LAST(x)
+#endif
+};
+
+
+class RegExpParser BASE_EMBEDDED {
+ public:
+  RegExpParser(FlatStringReader* in,
+               Handle<String>* error,
+               bool multiline_mode,
+               Zone* zone);
+
+  static bool ParseRegExp(FlatStringReader* input,
+                          bool multiline,
+                          RegExpCompileData* result,
+                          Zone* zone);
+
+  RegExpTree* ParsePattern();
+  RegExpTree* ParseDisjunction();
+  RegExpTree* ParseGroup();
+  RegExpTree* ParseCharacterClass();
+
+  // Parses a {...,...} quantifier and stores the range in the given
+  // out parameters.
+  bool ParseIntervalQuantifier(int* min_out, int* max_out);
+
+  // Parses and returns a single escaped character.  The character
+  // must not be 'b' or 'B' since they are usually handle specially.
+  uc32 ParseClassCharacterEscape();
+
+  // Checks whether the following is a length-digit hexadecimal number,
+  // and sets the value if it is.
+  bool ParseHexEscape(int length, uc32* value);
+
+  uc32 ParseOctalLiteral();
+
+  // Tries to parse the input as a back reference.  If successful it
+  // stores the result in the output parameter and returns true.  If
+  // it fails it will push back the characters read so the same characters
+  // can be reparsed.
+  bool ParseBackReferenceIndex(int* index_out);
+
+  CharacterRange ParseClassAtom(uc16* char_class);
+  RegExpTree* ReportError(Vector<const char> message);
+  void Advance();
+  void Advance(int dist);
+  void Reset(int pos);
+
+  // Reports whether the pattern might be used as a literal search string.
+  // Only use if the result of the parse is a single atom node.
+  bool simple();
+  bool contains_anchor() { return contains_anchor_; }
+  void set_contains_anchor() { contains_anchor_ = true; }
+  int captures_started() { return captures_ == NULL ? 0 : captures_->length(); }
+  int position() { return next_pos_ - 1; }
+  bool failed() { return failed_; }
+
+  static const int kMaxCaptures = 1 << 16;
+  static const uc32 kEndMarker = (1 << 21);
+
+ private:
+  enum SubexpressionType {
+    INITIAL,
+    CAPTURE,  // All positive values represent captures.
+    POSITIVE_LOOKAHEAD,
+    NEGATIVE_LOOKAHEAD,
+    GROUPING
+  };
+
+  class RegExpParserState : public ZoneObject {
+   public:
+    RegExpParserState(RegExpParserState* previous_state,
+                      SubexpressionType group_type,
+                      int disjunction_capture_index,
+                      Zone* zone)
+        : previous_state_(previous_state),
+          builder_(new(zone) RegExpBuilder(zone)),
+          group_type_(group_type),
+          disjunction_capture_index_(disjunction_capture_index) {}
+    // Parser state of containing expression, if any.
+    RegExpParserState* previous_state() { return previous_state_; }
+    bool IsSubexpression() { return previous_state_ != NULL; }
+    // RegExpBuilder building this regexp's AST.
+    RegExpBuilder* builder() { return builder_; }
+    // Type of regexp being parsed (parenthesized group or entire regexp).
+    SubexpressionType group_type() { return group_type_; }
+    // Index in captures array of first capture in this sub-expression, if any.
+    // Also the capture index of this sub-expression itself, if group_type
+    // is CAPTURE.
+    int capture_index() { return disjunction_capture_index_; }
+
+   private:
+    // Linked list implementation of stack of states.
+    RegExpParserState* previous_state_;
+    // Builder for the stored disjunction.
+    RegExpBuilder* builder_;
+    // Stored disjunction type (capture, look-ahead or grouping), if any.
+    SubexpressionType group_type_;
+    // Stored disjunction's capture index (if any).
+    int disjunction_capture_index_;
+  };
+
+  Isolate* isolate() { return isolate_; }
+  Zone* zone() const { return zone_; }
+
+  uc32 current() { return current_; }
+  bool has_more() { return has_more_; }
+  bool has_next() { return next_pos_ < in()->length(); }
+  uc32 Next();
+  FlatStringReader* in() { return in_; }
+  void ScanForCaptures();
+
+  Isolate* isolate_;
+  Zone* zone_;
+  Handle<String>* error_;
+  ZoneList<RegExpCapture*>* captures_;
+  FlatStringReader* in_;
+  uc32 current_;
+  int next_pos_;
+  // The capture count is only valid after we have scanned for captures.
+  int capture_count_;
+  bool has_more_;
+  bool multiline_;
+  bool simple_;
+  bool contains_anchor_;
+  bool is_scanned_for_captures_;
+  bool failed_;
+};
+
+// SNIP
+
+}  // namespace dart
+
+#endif  // VM_REGEXP_PARSER_H_