Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 524 insertions, 0 deletions

diff --git a/xpcom/ds/Tokenizer.h b/xpcom/ds/Tokenizer.h
new file mode 100644
index 0000000000..713b63f269
--- /dev/null
+++ b/xpcom/ds/Tokenizer.h
@@ -0,0 +1,524 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef Tokenizer_h__
+#define Tokenizer_h__
+
+#include <type_traits>
+
+#include "nsString.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/ScopeExit.h"
+#include "mozilla/UniquePtr.h"
+#include "nsTArray.h"
+
+namespace mozilla {
+
+template <typename TChar>
+class TokenizerBase {
+ public:
+  typedef nsTSubstring<TChar> TAString;
+  typedef nsTString<TChar> TString;
+  typedef nsTDependentString<TChar> TDependentString;
+  typedef nsTDependentSubstring<TChar> TDependentSubstring;
+
+  static TChar const sWhitespaces[];
+
+  /**
+   * The analyzer works with elements in the input cut to a sequence of token
+   * where each token has an elementary type
+   */
+  enum TokenType : uint32_t {
+    TOKEN_UNKNOWN,
+    TOKEN_RAW,
+    TOKEN_ERROR,
+    TOKEN_INTEGER,
+    TOKEN_WORD,
+    TOKEN_CHAR,
+    TOKEN_WS,
+    TOKEN_EOL,
+    TOKEN_EOF,
+    TOKEN_CUSTOM0 = 1000
+  };
+
+  enum ECaseSensitivity { CASE_SENSITIVE, CASE_INSENSITIVE };
+
+  /**
+   * Class holding the type and the value of a token.  It can be manually
+   * created to allow checks against it via methods of TTokenizer or are results
+   * of some of the TTokenizer's methods.
+   */
+  class Token {
+    TokenType mType;
+    TDependentSubstring mWord;
+    TString mCustom;
+    TChar mChar;
+    uint64_t mInteger;
+    ECaseSensitivity mCustomCaseInsensitivity;
+    bool mCustomEnabled;
+
+    // If this token is a result of the parsing process, this member is
+    // referencing a sub-string in the input buffer.  If this is externally
+    // created Token this member is left an empty string.
+    TDependentSubstring mFragment;
+
+    friend class TokenizerBase<TChar>;
+    void AssignFragment(typename TAString::const_char_iterator begin,
+                        typename TAString::const_char_iterator end);
+
+    static Token Raw();
+
+   public:
+    Token();
+    Token(const Token& aOther);
+    Token& operator=(const Token& aOther);
+
+    // Static constructors of tokens by type and value
+    static Token Word(TAString const& aWord);
+    static Token Char(TChar const aChar);
+    static Token Number(uint64_t const aNumber);
+    static Token Whitespace();
+    static Token NewLine();
+    static Token EndOfFile();
+    static Token Error();
+
+    // Compares the two tokens, type must be identical and value
+    // of one of the tokens must be 'any' or equal.
+    bool Equals(const Token& aOther) const;
+
+    TokenType Type() const { return mType; }
+    TChar AsChar() const;
+    TDependentSubstring AsString() const;
+    uint64_t AsInteger() const;
+
+    TDependentSubstring Fragment() const { return mFragment; }
+  };
+
+  /**
+   * Consumers may register a custom string that, when found in the input, is
+   * considered a token and returned by Next*() and accepted by Check*()
+   * methods. AddCustomToken() returns a reference to a token that can then be
+   * comapred using Token::Equals() againts the output from Next*() or be passed
+   * to Check*().
+   */
+  Token AddCustomToken(const TAString& aValue,
+                       ECaseSensitivity aCaseInsensitivity,
+                       bool aEnabled = true);
+  template <uint32_t N>
+  Token AddCustomToken(const TChar (&aValue)[N],
+                       ECaseSensitivity aCaseInsensitivity,
+                       bool aEnabled = true) {
+    return AddCustomToken(TDependentSubstring(aValue, N - 1),
+                          aCaseInsensitivity, aEnabled);
+  }
+  void RemoveCustomToken(Token& aToken);
+  /**
+   * Only applies to a custom type of a Token (see AddCustomToken above.)
+   * This turns on and off token recognition.  When a custom token is disabled,
+   * it's ignored as never added as a custom token.
+   */
+  void EnableCustomToken(Token const& aToken, bool aEnable);
+
+  /**
+   * Mode of tokenization.
+   * FULL tokenization, the default, recognizes built-in tokens and any custom
+   * tokens, if added. CUSTOM_ONLY will only recognize custom tokens, the rest
+   * is seen as 'raw'. This mode can be understood as a 'binary' mode.
+   */
+  enum class Mode { FULL, CUSTOM_ONLY };
+  void SetTokenizingMode(Mode aMode);
+
+  /**
+   * Return false iff the last Check*() call has returned false or when we've
+   * read past the end of the input string.
+   */
+  [[nodiscard]] bool HasFailed() const;
+
+ protected:
+  explicit TokenizerBase(const TChar* aWhitespaces = nullptr,
+                         const TChar* aAdditionalWordChars = nullptr);
+
+  // false if we have already read the EOF token.
+  bool HasInput() const;
+  // Main parsing function, it doesn't shift the read cursor, just returns the
+  // next token position.
+  typename TAString::const_char_iterator Parse(Token& aToken) const;
+  // Is read cursor at the end?
+  bool IsEnd(const typename TAString::const_char_iterator& caret) const;
+  // True, when we are at the end of the input data, but it has not been marked
+  // as complete yet.  In that case we cannot proceed with providing a
+  // multi-TChar token.
+  bool IsPending(const typename TAString::const_char_iterator& caret) const;
+  // Is read cursor on a character that is a word start?
+  bool IsWordFirst(const TChar aInput) const;
+  // Is read cursor on a character that is an in-word letter?
+  bool IsWord(const TChar aInput) const;
+  // Is read cursor on a character that is a valid number?
+  // TODO - support multiple radix
+  bool IsNumber(const TChar aInput) const;
+  // Is equal to the given custom token?
+  bool IsCustom(const typename TAString::const_char_iterator& caret,
+                const Token& aCustomToken, uint32_t* aLongest = nullptr) const;
+
+  // Friendly helper to assign a fragment on a Token
+  static void AssignFragment(Token& aToken,
+                             typename TAString::const_char_iterator begin,
+                             typename TAString::const_char_iterator end);
+
+#ifdef DEBUG
+  // This is called from inside Tokenizer methods to make sure the token is
+  // valid.
+  void Validate(Token const& aToken);
+#endif
+
+  // true iff we have already read the EOF token
+  bool mPastEof;
+  // true iff the last Check*() call has returned false, reverts to true on
+  // Rollback() call
+  bool mHasFailed;
+  // true if the input string is final (finished), false when we expect more
+  // data yet to be fed to the tokenizer (see IncrementalTokenizer derived
+  // class).
+  bool mInputFinished;
+  // custom only vs full tokenizing mode, see the Parse() method
+  Mode mMode;
+  // minimal raw data chunked delivery during incremental feed
+  uint32_t mMinRawDelivery;
+
+  // Customizable list of whitespaces
+  const TChar* mWhitespaces;
+  // Additinal custom word characters
+  const TChar* mAdditionalWordChars;
+
+  // All these point to the original buffer passed to the constructor or to the
+  // incremental buffer after FeedInput.
+  typename TAString::const_char_iterator
+      mCursor;  // Position of the current (actually next to read) token start
+  typename TAString::const_char_iterator mEnd;  // End of the input position
+
+  // This is the list of tokens user has registered with AddCustomToken()
+  nsTArray<UniquePtr<Token>> mCustomTokens;
+  uint32_t mNextCustomTokenID;
+
+ private:
+  TokenizerBase() = delete;
+  TokenizerBase(const TokenizerBase&) = delete;
+  TokenizerBase(TokenizerBase&&) = delete;
+  TokenizerBase(const TokenizerBase&&) = delete;
+  TokenizerBase& operator=(const TokenizerBase&) = delete;
+};
+
+/**
+ * This is a simple implementation of a lexical analyzer or maybe better
+ * called a tokenizer.
+ *
+ * Please use Tokenizer or Tokenizer16 classes, that are specializations
+ * of this template class.  Tokenizer is for ASCII input, Tokenizer16 may
+ * handle char16_t input, but doesn't recognize whitespaces or numbers
+ * other than standard `char` specialized Tokenizer class.
+ */
+template <typename TChar>
+class TTokenizer : public TokenizerBase<TChar> {
+ public:
+  typedef TokenizerBase<TChar> base;
+
+  /**
+   * @param aSource
+   *    The string to parse.
+   *    IMPORTANT NOTE: TTokenizer doesn't ensure the input string buffer
+   * lifetime. It's up to the consumer to make sure the string's buffer outlives
+   * the TTokenizer!
+   * @param aWhitespaces
+   *    If non-null TTokenizer will use this custom set of whitespaces for
+   * CheckWhite() and SkipWhites() calls. By default the list consists of space
+   * and tab.
+   * @param aAdditionalWordChars
+   *    If non-null it will be added to the list of characters that consist a
+   * word. This is useful when you want to accept e.g. '-' in HTTP headers. By
+   * default a word character is consider any character for which upper case
+   *    is different from lower case.
+   *
+   * If there is an overlap between aWhitespaces and aAdditionalWordChars, the
+   * check for word characters is made first.
+   */
+  explicit TTokenizer(const typename base::TAString& aSource,
+                      const TChar* aWhitespaces = nullptr,
+                      const TChar* aAdditionalWordChars = nullptr);
+  explicit TTokenizer(const TChar* aSource, const TChar* aWhitespaces = nullptr,
+                      const TChar* aAdditionalWordChars = nullptr);
+
+  /**
+   * When there is still anything to read from the input, tokenize it, store the
+   * token type and value to aToken result and shift the cursor past this just
+   * parsed token.  Each call to Next() reads another token from the input and
+   * shifts the cursor. Returns false if we have passed the end of the input.
+   */
+  [[nodiscard]] bool Next(typename base::Token& aToken);
+
+  /**
+   * Parse the token on the input read cursor position, check its type is equal
+   * to aTokenType and if so, put it into aResult, shift the cursor and return
+   * true.  Otherwise, leave the input read cursor position intact and return
+   * false.
+   */
+  [[nodiscard]] bool Check(const typename base::TokenType aTokenType,
+                           typename base::Token& aResult);
+  /**
+   * Same as above method, just compares both token type and token value passed
+   * in aToken. When both the type and the value equals, shift the cursor and
+   * return true.  Otherwise return false.
+   */
+  [[nodiscard]] bool Check(const typename base::Token& aToken);
+
+  /**
+   * SkipWhites method (below) may also skip new line characters automatically.
+   */
+  enum WhiteSkipping {
+    /**
+     * SkipWhites will only skip what is defined as a white space (default).
+     */
+    DONT_INCLUDE_NEW_LINE = 0,
+    /**
+     * SkipWhites will skip definited white spaces as well as new lines
+     * automatically.
+     */
+    INCLUDE_NEW_LINE = 1
+  };
+
+  /**
+   * Skips any occurence of whitespaces specified in mWhitespaces member,
+   * optionally skip also new lines.
+   */
+  void SkipWhites(WhiteSkipping aIncludeNewLines = DONT_INCLUDE_NEW_LINE);
+
+  /**
+   * Skips all tokens until the given one is found or EOF is hit.  The token
+   * or EOF are next to read.
+   */
+  void SkipUntil(typename base::Token const& aToken);
+
+  // These are mostly shortcuts for the Check() methods above.
+
+  /**
+   * Check whitespace character is present.
+   */
+  [[nodiscard]] bool CheckWhite() { return Check(base::Token::Whitespace()); }
+  /**
+   * Check there is a single character on the read cursor position.  If so,
+   * shift the read cursor position and return true.  Otherwise false.
+   */
+  [[nodiscard]] bool CheckChar(const TChar aChar) {
+    return Check(base::Token::Char(aChar));
+  }
+  /**
+   * This is a customizable version of CheckChar.  aClassifier is a function
+   * called with value of the character on the current input read position.  If
+   * this user function returns true, read cursor is shifted and true returned.
+   * Otherwise false. The user classifiction function is not called when we are
+   * at or past the end and false is immediately returned.
+   */
+  [[nodiscard]] bool CheckChar(bool (*aClassifier)(const TChar aChar));
+  /**
+   * Check for a whole expected word.
+   */
+  [[nodiscard]] bool CheckWord(const typename base::TAString& aWord) {
+    return Check(base::Token::Word(aWord));
+  }
+  /**
+   * Shortcut for literal const word check with compile time length calculation.
+   */
+  template <uint32_t N>
+  [[nodiscard]] bool CheckWord(const TChar (&aWord)[N]) {
+    return Check(
+        base::Token::Word(typename base::TDependentString(aWord, N - 1)));
+  }
+  /**
+   * Helper to check for a string compound of multiple tokens like "foo bar".
+   * The match is binary-exact, a white space or a delimiter character in the
+   * phrase must match exactly the characters in the input.
+   */
+  [[nodiscard]] bool CheckPhrase(const typename base::TAString& aPhrase);
+  template <uint32_t N>
+  [[nodiscard]] bool CheckPhrase(const TChar (&aPhrase)[N]) {
+    return CheckPhrase(typename base::TDependentString(aPhrase, N - 1));
+  }
+  /**
+   * Checks \r, \n or \r\n.
+   */
+  [[nodiscard]] bool CheckEOL() { return Check(base::Token::NewLine()); }
+  /**
+   * Checks we are at the end of the input string reading.  If so, shift past
+   * the end and returns true.  Otherwise does nothing and returns false.
+   */
+  [[nodiscard]] bool CheckEOF() { return Check(base::Token::EndOfFile()); }
+
+  /**
+   * These are shortcuts to obtain the value immediately when the token type
+   * matches.
+   */
+  [[nodiscard]] bool ReadChar(TChar* aValue);
+  [[nodiscard]] bool ReadChar(bool (*aClassifier)(const TChar aChar),
+                              TChar* aValue);
+  [[nodiscard]] bool ReadWord(typename base::TAString& aValue);
+  [[nodiscard]] bool ReadWord(typename base::TDependentSubstring& aValue);
+
+  /**
+   * This is an integer read helper.  It returns false and doesn't move the read
+   * cursor when any of the following happens:
+   *  - the token at the read cursor is not an integer
+   *  - the final number doesn't fit the T type
+   * Otherwise true is returned, aValue is filled with the integral number
+   * and the cursor is moved forward.
+   */
+  template <typename T>
+  [[nodiscard]] bool ReadInteger(T* aValue) {
+    MOZ_RELEASE_ASSERT(aValue);
+
+    typename base::TAString::const_char_iterator rollback = mRollback;
+    typename base::TAString::const_char_iterator cursor = base::mCursor;
+    typename base::Token t;
+    if (!Check(base::TOKEN_INTEGER, t)) {
+      return false;
+    }
+
+    mozilla::CheckedInt<T> checked(t.AsInteger());
+    if (!checked.isValid()) {
+      // Move to a state as if Check() call has failed
+      mRollback = rollback;
+      base::mCursor = cursor;
+      base::mHasFailed = true;
+      return false;
+    }
+
+    *aValue = checked.value();
+    return true;
+  }
+
+  /**
+   * Same as above, but accepts an integer with an optional minus sign.
+   */
+  template <typename T, typename V = std::enable_if_t<
+                            std::is_signed_v<std::remove_pointer_t<T>>,
+                            std::remove_pointer_t<T>>>
+  [[nodiscard]] bool ReadSignedInteger(T* aValue) {
+    MOZ_RELEASE_ASSERT(aValue);
+
+    typename base::TAString::const_char_iterator rollback = mRollback;
+    typename base::TAString::const_char_iterator cursor = base::mCursor;
+    auto revert = MakeScopeExit([&] {
+      // Move to a state as if Check() call has failed
+      mRollback = rollback;
+      base::mCursor = cursor;
+      base::mHasFailed = true;
+    });
+
+    // Using functional raw access because '-' could be part of the word set
+    // making CheckChar('-') not work.
+    bool minus = CheckChar([](const TChar aChar) { return aChar == '-'; });
+
+    typename base::Token t;
+    if (!Check(base::TOKEN_INTEGER, t)) {
+      return false;
+    }
+
+    mozilla::CheckedInt<T> checked(t.AsInteger());
+    if (minus) {
+      checked *= -1;
+    }
+
+    if (!checked.isValid()) {
+      return false;
+    }
+
+    *aValue = checked.value();
+    revert.release();
+    return true;
+  }
+
+  /**
+   * Returns the read cursor position back as it was before the last call of any
+   * parsing method of TTokenizer (Next, Check*, Skip*, Read*) so that the last
+   * operation can be repeated. Rollback cannot be used multiple times, it only
+   * reverts the last successfull parse operation.  It also cannot be used
+   * before any parsing operation has been called on the TTokenizer.
+   */
+  void Rollback();
+
+  /**
+   * Record() and Claim() are collecting the input as it is being parsed to
+   * obtain a substring between particular syntax bounderies defined by any
+   * recursive descent parser or simple parser the TTokenizer is used to read
+   * the input for. Inlucsion of a token that has just been parsed can be
+   * controlled using an arguemnt.
+   */
+  enum ClaimInclusion {
+    /**
+     * Include resulting (or passed) token of the last lexical analyzer
+     * operation in the result.
+     */
+    INCLUDE_LAST,
+    /**
+     * Do not include it.
+     */
+    EXCLUDE_LAST
+  };
+
+  /**
+   * Start the process of recording.  Based on aInclude value the begining of
+   * the recorded sub-string is at the current position (EXCLUDE_LAST) or at the
+   * position before the last parsed token (INCLUDE_LAST).
+   */
+  void Record(ClaimInclusion aInclude = EXCLUDE_LAST);
+  /**
+   * Claim result of the record started with Record() call before.  Depending on
+   * aInclude the ending of the sub-string result includes or excludes the last
+   * parsed or checked token.
+   */
+  void Claim(typename base::TAString& aResult,
+             ClaimInclusion aInclude = EXCLUDE_LAST);
+  void Claim(typename base::TDependentSubstring& aResult,
+             ClaimInclusion aInclude = EXCLUDE_LAST);
+
+  /**
+   * If aToken is found, aResult is set to the substring between the current
+   * position and the position of aToken, potentially including aToken depending
+   * on aInclude.
+   * If aToken isn't found aResult is set to the substring between the current
+   * position and the end of the string.
+   * If aToken is found, the method returns true. Otherwise it returns false.
+   *
+   * Calling Rollback() after ReadUntil() will return the read cursor to the
+   * position it had before ReadUntil was called.
+   */
+  [[nodiscard]] bool ReadUntil(typename base::Token const& aToken,
+                               typename base::TDependentSubstring& aResult,
+                               ClaimInclusion aInclude = EXCLUDE_LAST);
+  [[nodiscard]] bool ReadUntil(typename base::Token const& aToken,
+                               typename base::TAString& aResult,
+                               ClaimInclusion aInclude = EXCLUDE_LAST);
+
+ protected:
+  // All these point to the original buffer passed to the TTokenizer's
+  // constructor
+  typename base::TAString::const_char_iterator
+      mRecord;  // Position where the recorded sub-string for Claim() is
+  typename base::TAString::const_char_iterator
+      mRollback;  // Position of the previous token start
+
+ private:
+  TTokenizer() = delete;
+  TTokenizer(const TTokenizer&) = delete;
+  TTokenizer(TTokenizer&&) = delete;
+  TTokenizer(const TTokenizer&&) = delete;
+  TTokenizer& operator=(const TTokenizer&) = delete;
+};
+
+typedef TTokenizer<char> Tokenizer;
+typedef TTokenizer<char16_t> Tokenizer16;
+
+}  // namespace mozilla
+
+#endif  // Tokenizer_h__