gecko-dev/xpcom/string/nsTString.h

/* -*- 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/. */
// IWYU pragma: private, include "nsString.h"

/**
 * This is the canonical null-terminated string class.  All subclasses
 * promise null-terminated storage.  Instances of this class allocate
 * strings on the heap.
 *
 * NAMES:
 *   nsString for wide characters
 *   nsCString for narrow characters
 *
 * This class is also known as nsAFlat[C]String, where "flat" is used
 * to denote a null-terminated string.
 */
class nsTString_CharT : public nsTSubstring_CharT
{
public:

  typedef nsTString_CharT self_type;

public:

  /**
   * constructors
   */

  nsTString_CharT()
    : substring_type(ClassFlags::NULL_TERMINATED)
  {
  }

  explicit
  nsTString_CharT(const char_type* aData, size_type aLength = size_type(-1))
    : substring_type(ClassFlags::NULL_TERMINATED)
  {
    Assign(aData, aLength);
  }

#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
  explicit
  nsTString_CharT(char16ptr_t aStr, size_type aLength = size_type(-1))
    : substring_type(ClassFlags::NULL_TERMINATED)
  {
    Assign(static_cast<const char16_t*>(aStr), aLength);
  }
#endif

  nsTString_CharT(const self_type& aStr)
    : substring_type(ClassFlags::NULL_TERMINATED)
  {
    Assign(aStr);
  }

  MOZ_IMPLICIT nsTString_CharT(const substring_tuple_type& aTuple)
    : substring_type(ClassFlags::NULL_TERMINATED)
  {
    Assign(aTuple);
  }

  explicit
  nsTString_CharT(const substring_type& aReadable)
    : substring_type(ClassFlags::NULL_TERMINATED)
  {
    Assign(aReadable);
  }


  // |operator=| does not inherit, so we must define our own
  self_type& operator=(char_type aChar)
  {
    Assign(aChar);
    return *this;
  }
  self_type& operator=(const char_type* aData)
  {
    Assign(aData);
    return *this;
  }
  self_type& operator=(const self_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
  self_type& operator=(const char16ptr_t aStr)
  {
    Assign(static_cast<const char16_t*>(aStr));
    return *this;
  }
#endif
  self_type& operator=(const substring_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const substring_tuple_type& aTuple)
  {
    Assign(aTuple);
    return *this;
  }

  /**
   * returns the null-terminated string
   */

#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
  MOZ_NO_DANGLING_ON_TEMPORARIES char16ptr_t get() const
#else
  MOZ_NO_DANGLING_ON_TEMPORARIES const char_type* get() const
#endif
  {
    return mData;
  }


  /**
   * returns character at specified index.
   *
   * NOTE: unlike nsTSubstring::CharAt, this function allows you to index
   *       the null terminator character.
   */

  char_type CharAt(index_type aIndex) const
  {
    NS_ASSERTION(aIndex <= mLength, "index exceeds allowable range");
    return mData[aIndex];
  }

  char_type operator[](index_type aIndex) const
  {
    return CharAt(aIndex);
  }


#if MOZ_STRING_WITH_OBSOLETE_API


  /**
   *  Search for the given substring within this string.
   *
   *  @param   aString is substring to be sought in this
   *  @param   aIgnoreCase selects case sensitivity
   *  @param   aOffset tells us where in this string to start searching
   *  @param   aCount tells us how far from the offset we are to search. Use
   *           -1 to search the whole string.
   *  @return  offset in string, or kNotFound
   */

  int32_t Find(const nsCString& aString, bool aIgnoreCase = false,
               int32_t aOffset = 0, int32_t aCount = -1) const;
  int32_t Find(const char* aString, bool aIgnoreCase = false,
               int32_t aOffset = 0, int32_t aCount = -1) const;

#ifdef CharT_is_PRUnichar
  int32_t Find(const nsString& aString, int32_t aOffset = 0,
               int32_t aCount = -1) const;
  int32_t Find(const char16_t* aString, int32_t aOffset = 0,
               int32_t aCount = -1) const;
#ifdef MOZ_USE_CHAR16_WRAPPER
  int32_t Find(char16ptr_t aString, int32_t aOffset = 0,
               int32_t aCount = -1) const
  {
    return Find(static_cast<const char16_t*>(aString), aOffset, aCount);
  }
#endif
#endif


  /**
   * This methods scans the string backwards, looking for the given string
   *
   * @param   aString is substring to be sought in this
   * @param   aIgnoreCase tells us whether or not to do caseless compare
   * @param   aOffset tells us where in this string to start searching.
   *          Use -1 to search from the end of the string.
   * @param   aCount tells us how many iterations to make starting at the
   *          given offset.
   * @return  offset in string, or kNotFound
   */

  int32_t RFind(const nsCString& aString, bool aIgnoreCase = false,
                int32_t aOffset = -1, int32_t aCount = -1) const;
  int32_t RFind(const char* aCString, bool aIgnoreCase = false,
                int32_t aOffset = -1, int32_t aCount = -1) const;

#ifdef CharT_is_PRUnichar
  int32_t RFind(const nsString& aString, int32_t aOffset = -1,
                int32_t aCount = -1) const;
  int32_t RFind(const char16_t* aString, int32_t aOffset = -1,
                int32_t aCount = -1) const;
#endif


  /**
   *  Search for given char within this string
   *
   *  @param   aChar is the character to search for
   *  @param   aOffset tells us where in this string to start searching
   *  @param   aCount tells us how far from the offset we are to search.
   *           Use -1 to search the whole string.
   *  @return  offset in string, or kNotFound
   */

  // int32_t FindChar( char16_t aChar, int32_t aOffset=0, int32_t aCount=-1 ) const;
  int32_t RFindChar(char16_t aChar, int32_t aOffset = -1,
                    int32_t aCount = -1) const;


  /**
   * This method searches this string for the first character found in
   * the given string.
   *
   * @param aString contains set of chars to be found
   * @param aOffset tells us where in this string to start searching
   *        (counting from left)
   * @return offset in string, or kNotFound
   */

  int32_t FindCharInSet(const char* aString, int32_t aOffset = 0) const;
  int32_t FindCharInSet(const self_type& aString, int32_t aOffset = 0) const
  {
    return FindCharInSet(aString.get(), aOffset);
  }

#ifdef CharT_is_PRUnichar
  int32_t FindCharInSet(const char16_t* aString, int32_t aOffset = 0) const;
#endif


  /**
   * This method searches this string for the last character found in
   * the given string.
   *
   * @param aString contains set of chars to be found
   * @param aOffset tells us where in this string to start searching
   *        (counting from left)
   * @return offset in string, or kNotFound
   */

  int32_t RFindCharInSet(const char_type* aString, int32_t aOffset = -1) const;
  int32_t RFindCharInSet(const self_type& aString, int32_t aOffset = -1) const
  {
    return RFindCharInSet(aString.get(), aOffset);
  }


  /**
   * Compares a given string to this string.
   *
   * @param   aString is the string to be compared
   * @param   aIgnoreCase tells us how to treat case
   * @param   aCount tells us how many chars to compare
   * @return  -1,0,1
   */

#ifdef CharT_is_char
  int32_t Compare(const char* aString, bool aIgnoreCase = false,
                  int32_t aCount = -1) const;
#endif


  /**
   * Equality check between given string and this string.
   *
   * @param   aString is the string to check
   * @param   aIgnoreCase tells us how to treat case
   * @param   aCount tells us how many chars to compare
   * @return  boolean
   */
#ifdef CharT_is_char
  bool EqualsIgnoreCase(const char* aString, int32_t aCount = -1) const
  {
    return Compare(aString, true, aCount) == 0;
  }
#else
  bool EqualsIgnoreCase(const char* aString, int32_t aCount = -1) const;


#endif // !CharT_is_PRUnichar

  /**
   * Perform string to double-precision float conversion.
   *
   * @param   aErrorCode will contain error if one occurs
   * @return  double-precision float rep of string value
   */
  double ToDouble(nsresult* aErrorCode) const;

  /**
   * Perform string to single-precision float conversion.
   *
   * @param   aErrorCode will contain error if one occurs
   * @return  single-precision float rep of string value
   */
  float ToFloat(nsresult* aErrorCode) const
  {
    return (float)ToDouble(aErrorCode);
  }


  /**
   * Perform string to int conversion.
   * @param   aErrorCode will contain error if one occurs
   * @param   aRadix tells us which radix to assume; kAutoDetect tells us to determine the radix for you.
   * @return  int rep of string value, and possible (out) error code
   */
  int32_t ToInteger(nsresult* aErrorCode, uint32_t aRadix = kRadix10) const;

  /**
   * Perform string to 64-bit int conversion.
   * @param   aErrorCode will contain error if one occurs
   * @param   aRadix tells us which radix to assume; kAutoDetect tells us to determine the radix for you.
   * @return  64-bit int rep of string value, and possible (out) error code
   */
  int64_t ToInteger64(nsresult* aErrorCode, uint32_t aRadix = kRadix10) const;


  /**
   * |Left|, |Mid|, and |Right| are annoying signatures that seem better almost
   * any _other_ way than they are now.  Consider these alternatives
   *
   * aWritable = aReadable.Left(17);   // ...a member function that returns a |Substring|
   * aWritable = Left(aReadable, 17);  // ...a global function that returns a |Substring|
   * Left(aReadable, 17, aWritable);   // ...a global function that does the assignment
   *
   * as opposed to the current signature
   *
   * aReadable.Left(aWritable, 17);    // ...a member function that does the assignment
   *
   * or maybe just stamping them out in favor of |Substring|, they are just duplicate functionality
   *
   * aWritable = Substring(aReadable, 0, 17);
   */

  size_type Mid(self_type& aResult, uint32_t aStartPos, uint32_t aCount) const;

  size_type Left(self_type& aResult, size_type aCount) const
  {
    return Mid(aResult, 0, aCount);
  }

  size_type Right(self_type& aResult, size_type aCount) const
  {
    aCount = XPCOM_MIN(mLength, aCount);
    return Mid(aResult, mLength - aCount, aCount);
  }


  /**
   * Set a char inside this string at given index
   *
   * @param aChar is the char you want to write into this string
   * @param anIndex is the ofs where you want to write the given char
   * @return TRUE if successful
   */

  bool SetCharAt(char16_t aChar, uint32_t aIndex);


  /**
   *  These methods are used to remove all occurrences of the
   *  characters found in aSet from this string.
   *
   *  @param  aSet -- characters to be cut from this
   */
#ifdef CharT_is_PRUnichar
  using nsTSubstring_CharT::StripChars;
#endif
  void StripChars(const char* aSet);
  bool StripChars(const char* aSet, const fallible_t&);


  /**
   *  This method strips whitespace throughout the string.
   */
  void StripWhitespace();
  bool StripWhitespace(const fallible_t&);


  /**
   *  swaps occurence of 1 string for another
   */

  void ReplaceChar(char_type aOldChar, char_type aNewChar);
  void ReplaceChar(const char* aSet, char_type aNewChar);
#ifdef CharT_is_PRUnichar
  void ReplaceChar(const char16_t* aSet, char16_t aNewChar);
#endif
  /**
   * Replace all occurrences of aTarget with aNewValue.
   * The complexity of this function is O(n+m), n being the length of the string
   * and m being the length of aNewValue.
   */
  void ReplaceSubstring(const self_type& aTarget, const self_type& aNewValue);
  void ReplaceSubstring(const char_type* aTarget, const char_type* aNewValue);
  MOZ_MUST_USE bool ReplaceSubstring(const self_type& aTarget,
                                     const self_type& aNewValue,
                                     const fallible_t&);
  MOZ_MUST_USE bool ReplaceSubstring(const char_type* aTarget,
                                     const char_type* aNewValue,
                                     const fallible_t&);


  /**
   *  This method trims characters found in aTrimSet from
   *  either end of the underlying string.
   *
   *  @param   aSet -- contains chars to be trimmed from both ends
   *  @param   aEliminateLeading
   *  @param   aEliminateTrailing
   *  @param   aIgnoreQuotes -- if true, causes surrounding quotes to be ignored
   *  @return  this
   */
  void Trim(const char* aSet, bool aEliminateLeading = true,
            bool aEliminateTrailing = true, bool aIgnoreQuotes = false);

  /**
   *  This method strips whitespace from string.
   *  You can control whether whitespace is yanked from start and end of
   *  string as well.
   *
   *  @param   aEliminateLeading controls stripping of leading ws
   *  @param   aEliminateTrailing controls stripping of trailing ws
   */
  void CompressWhitespace(bool aEliminateLeading = true,
                          bool aEliminateTrailing = true);

#endif // !MOZ_STRING_WITH_OBSOLETE_API

  /**
   * Allow this string to be bound to a character buffer
   * until the string is rebound or mutated; the caller
   * must ensure that the buffer outlives the string.
   */
  void Rebind(const char_type* aData, size_type aLength);

  /**
   * verify restrictions for dependent strings
   */
  void AssertValidDependentString()
  {
    NS_ASSERTION(mData, "nsTDependentString must wrap a non-NULL buffer");
    NS_ASSERTION(mLength != size_type(-1), "nsTDependentString has bogus length");
    NS_ASSERTION(mData[mLength] == 0,
                 "nsTDependentString must wrap only null-terminated strings. "
                 "You are probably looking for nsTDependentSubstring.");
  }


protected:

  // allow subclasses to initialize fields directly
  nsTString_CharT(char_type* aData, size_type aLength, DataFlags aDataFlags,
                  ClassFlags aClassFlags)
    : substring_type(aData, aLength, aDataFlags,
                     aClassFlags | ClassFlags::NULL_TERMINATED)
  {
  }

  struct Segment {
    uint32_t mBegin, mLength;
    Segment(uint32_t aBegin, uint32_t aLength)
      : mBegin(aBegin)
      , mLength(aLength)
    {}
  };
};


class nsTFixedString_CharT : public nsTString_CharT
{
public:

  typedef nsTFixedString_CharT self_type;
  typedef nsTFixedString_CharT fixed_string_type;

public:

  /**
   * @param aData
   *        fixed-size buffer to be used by the string (the contents of
   *        this buffer may be modified by the string)
   * @param aStorageSize
   *        the size of the fixed buffer
   * @param aLength (optional)
   *        the length of the string already contained in the buffer
   */

  nsTFixedString_CharT(char_type* aData, size_type aStorageSize)
    : string_type(aData, uint32_t(char_traits::length(aData)),
                  DataFlags::TERMINATED | DataFlags::FIXED,
                  ClassFlags::FIXED)
    , mFixedCapacity(aStorageSize - 1)
    , mFixedBuf(aData)
  {
  }

  nsTFixedString_CharT(char_type* aData, size_type aStorageSize,
                       size_type aLength)
    : string_type(aData, aLength, DataFlags::TERMINATED | DataFlags::FIXED,
                  ClassFlags::FIXED)
    , mFixedCapacity(aStorageSize - 1)
    , mFixedBuf(aData)
  {
    // null-terminate
    mFixedBuf[aLength] = char_type(0);
  }

  // |operator=| does not inherit, so we must define our own
  self_type& operator=(char_type aChar)
  {
    Assign(aChar);
    return *this;
  }
  self_type& operator=(const char_type* aData)
  {
    Assign(aData);
    return *this;
  }
  self_type& operator=(const substring_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const substring_tuple_type& aTuple)
  {
    Assign(aTuple);
    return *this;
  }

protected:

  friend class nsTSubstring_CharT;

  size_type  mFixedCapacity;
  char_type* mFixedBuf;
};


/**
 * nsTAutoString_CharT
 *
 * Subclass of nsTString_CharT that adds support for stack-based string
 * allocation.  It is normally not a good idea to use this class on the
 * heap, because it will allocate space which may be wasted if the string
 * it contains is significantly smaller or any larger than 64 characters.
 *
 * NAMES:
 *   nsAutoString for wide characters
 *   nsAutoCString for narrow characters
 */
class MOZ_NON_MEMMOVABLE nsTAutoString_CharT : public nsTFixedString_CharT
{
public:

  typedef nsTAutoString_CharT self_type;

public:

  /**
   * constructors
   */

  nsTAutoString_CharT()
    : fixed_string_type(mStorage, kDefaultStorageSize, 0)
  {
  }

  explicit
  nsTAutoString_CharT(char_type aChar)
    : fixed_string_type(mStorage, kDefaultStorageSize, 0)
  {
    Assign(aChar);
  }

  explicit
  nsTAutoString_CharT(const char_type* aData, size_type aLength = size_type(-1))
    : fixed_string_type(mStorage, kDefaultStorageSize, 0)
  {
    Assign(aData, aLength);
  }

#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
  explicit
  nsTAutoString_CharT(char16ptr_t aData, size_type aLength = size_type(-1))
    : nsTAutoString_CharT(static_cast<const char16_t*>(aData), aLength)
  {
  }
#endif

  nsTAutoString_CharT(const self_type& aStr)
    : fixed_string_type(mStorage, kDefaultStorageSize, 0)
  {
    Assign(aStr);
  }

  explicit
  nsTAutoString_CharT(const substring_type& aStr)
    : fixed_string_type(mStorage, kDefaultStorageSize, 0)
  {
    Assign(aStr);
  }

  MOZ_IMPLICIT nsTAutoString_CharT(const substring_tuple_type& aTuple)
    : fixed_string_type(mStorage, kDefaultStorageSize, 0)
  {
    Assign(aTuple);
  }

  // |operator=| does not inherit, so we must define our own
  self_type& operator=(char_type aChar)
  {
    Assign(aChar);
    return *this;
  }
  self_type& operator=(const char_type* aData)
  {
    Assign(aData);
    return *this;
  }
#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
  self_type& operator=(char16ptr_t aStr)
  {
    Assign(aStr);
    return *this;
  }
#endif
  self_type& operator=(const self_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const substring_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const substring_tuple_type& aTuple)
  {
    Assign(aTuple);
    return *this;
  }

  enum
  {
    kDefaultStorageSize = 64
  };

private:

  char_type mStorage[kDefaultStorageSize];
};


//
// nsAutoString stores pointers into itself which are invalidated when an
// nsTArray is resized, so nsTArray must not be instantiated with nsAutoString
// elements!
//
template<class E> class nsTArrayElementTraits;
template<>
class nsTArrayElementTraits<nsTAutoString_CharT>
{
public:
  template<class A> struct Dont_Instantiate_nsTArray_of;
  template<class A> struct Instead_Use_nsTArray_of;

  static Dont_Instantiate_nsTArray_of<nsTAutoString_CharT>*
  Construct(Instead_Use_nsTArray_of<nsTString_CharT>* aE)
  {
    return 0;
  }
  template<class A>
  static Dont_Instantiate_nsTArray_of<nsTAutoString_CharT>*
  Construct(Instead_Use_nsTArray_of<nsTString_CharT>* aE, const A& aArg)
  {
    return 0;
  }
  static Dont_Instantiate_nsTArray_of<nsTAutoString_CharT>*
  Destruct(Instead_Use_nsTArray_of<nsTString_CharT>* aE)
  {
    return 0;
  }
};

/**
 * nsTXPIDLString extends nsTString such that:
 *
 *   (1) mData can be null
 *   (2) objects of this type can be automatically cast to |const CharT*|
 *   (3) getter_Copies method is supported to adopt data allocated with
 *       moz_xmalloc, such as "out string" parameters in XPIDL.
 *
 * NAMES:
 *   nsXPIDLString for wide characters
 *   nsXPIDLCString for narrow characters
 */
class nsTXPIDLString_CharT : public nsTString_CharT
{
public:

  typedef nsTXPIDLString_CharT self_type;

public:

  nsTXPIDLString_CharT()
    : string_type(char_traits::sEmptyBuffer, 0,
                  DataFlags::TERMINATED | DataFlags::VOIDED, ClassFlags(0))
  {
  }

  // copy-constructor required to avoid default
  nsTXPIDLString_CharT(const self_type& aStr)
    : string_type(char_traits::sEmptyBuffer, 0,
                  DataFlags::TERMINATED | DataFlags::VOIDED, ClassFlags(0))
  {
    Assign(aStr);
  }

  // return nullptr if we are voided
#if defined(CharT_is_PRUnichar) && defined(MOZ_USE_CHAR16_WRAPPER)
  MOZ_NO_DANGLING_ON_TEMPORARIES char16ptr_t get() const
#else
  MOZ_NO_DANGLING_ON_TEMPORARIES const char_type* get() const
#endif
  {
    return (mDataFlags & DataFlags::VOIDED) ? nullptr : mData;
  }

  // this case operator is the reason why this class cannot just be a
  // typedef for nsTString
  operator const char_type*() const
  {
    return get();
  }

  // need this to diambiguous operator[int]
  char_type operator[](int32_t aIndex) const
  {
    return CharAt(index_type(aIndex));
  }

  // |operator=| does not inherit, so we must define our own
  self_type& operator=(char_type aChar)
  {
    Assign(aChar);
    return *this;
  }
  self_type& operator=(const char_type* aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const self_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const substring_type& aStr)
  {
    Assign(aStr);
    return *this;
  }
  self_type& operator=(const substring_tuple_type& aTuple)
  {
    Assign(aTuple);
    return *this;
  }
};


/**
 * getter_Copies support for adopting raw string out params that are
 * heap-allocated, e.g.:
 *
 *    char* gStr;
 *    void GetBlah(char** aStr)
 *    {
 *      *aStr = strdup(gStr);
 *    }
 *
 *    // This works, but is clumsy.
 *    void Inelegant()
 *    {
 *      char* buf;
 *      GetBlah(&buf);
 *      nsCString str;
 *      str.Adopt(buf);
 *      // ...
 *    }
 *
 *    // This is nicer.
 *    void Elegant()
 *    {
 *      nsCString str;
 *      GetBlah(getter_Copies(str));
 *      // ...
 *    }
 */
class MOZ_STACK_CLASS nsTGetterCopies_CharT
{
public:
  typedef CharT char_type;

  explicit nsTGetterCopies_CharT(nsTSubstring_CharT& aStr)
    : mString(aStr)
    , mData(nullptr)
  {
  }

  ~nsTGetterCopies_CharT()
  {
    mString.Adopt(mData); // OK if mData is null
  }

  operator char_type**()
  {
    return &mData;
  }

private:
  nsTSubstring_CharT& mString;
  char_type* mData;
};

// See the comment above nsTGetterCopies_CharT for how to use this.
inline nsTGetterCopies_CharT
getter_Copies(nsTSubstring_CharT& aString)
{
  return nsTGetterCopies_CharT(aString);
}