Add m-esr52 at 52.6.0

1 files changed, 1596 insertions, 0 deletions

diff --git a/xpcom/glue/nsStringAPI.h b/xpcom/glue/nsStringAPI.h
new file mode 100644
index 000000000..d5e368695
--- /dev/null
+++ b/xpcom/glue/nsStringAPI.h
@@ -0,0 +1,1596 @@
+/* -*- 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/. */
+
+/**
+ * This header provides wrapper classes around the frozen string API
+ * which are roughly equivalent to the internal string classes.
+ */
+
+#ifdef MOZILLA_INTERNAL_API
+#error nsStringAPI.h is only usable from non-MOZILLA_INTERNAL_API code!
+#endif
+
+#ifndef nsStringAPI_h__
+#define nsStringAPI_h__
+
+#include "mozilla/Attributes.h"
+#include "mozilla/Char16.h"
+
+#include "nsXPCOMStrings.h"
+#include "nsISupportsImpl.h"
+#include "mozilla/Logging.h"
+#include "nsTArray.h"
+
+/**
+ * Comparison function for use with nsACString::Equals
+ */
+NS_HIDDEN_(int32_t) CaseInsensitiveCompare(const char* aStrA, const char* aStrB,
+                                           uint32_t aLength);
+
+class nsAString
+{
+public:
+  typedef char16_t  char_type;
+  typedef nsAString self_type;
+  typedef uint32_t  size_type;
+  typedef uint32_t  index_type;
+
+  /**
+   * Returns the length, beginning, and end of a string in one operation.
+   */
+  NS_HIDDEN_(uint32_t) BeginReading(const char_type** aBegin,
+                                    const char_type** aEnd = nullptr) const;
+
+  NS_HIDDEN_(const char_type*) BeginReading() const;
+  NS_HIDDEN_(const char_type*) EndReading() const;
+
+  NS_HIDDEN_(char_type) CharAt(uint32_t aPos) const
+  {
+    NS_ASSERTION(aPos < Length(), "Out of bounds");
+    return BeginReading()[aPos];
+  }
+  NS_HIDDEN_(char_type) operator [](uint32_t aPos) const
+  {
+    return CharAt(aPos);
+  }
+  NS_HIDDEN_(char_type) First() const
+  {
+    return CharAt(0);
+  }
+  NS_HIDDEN_(char_type) Last() const
+  {
+    const char_type* data;
+    uint32_t dataLen = NS_StringGetData(*this, &data);
+    return data[dataLen - 1];
+  }
+
+  /**
+   * Get the length, begin writing, and optionally set the length of a
+   * string all in one operation.
+   *
+   * @param   newSize Size the string to this length. Pass UINT32_MAX
+   *                  to leave the length unchanged.
+   * @return  The new length of the string, or 0 if resizing failed.
+   */
+  NS_HIDDEN_(uint32_t) BeginWriting(char_type** aBegin,
+                                    char_type** aEnd = nullptr,
+                                    uint32_t aNewSize = UINT32_MAX);
+
+  NS_HIDDEN_(char_type*) BeginWriting(uint32_t = UINT32_MAX);
+  NS_HIDDEN_(char_type*) EndWriting();
+
+  NS_HIDDEN_(bool) SetLength(uint32_t aLen);
+
+  NS_HIDDEN_(size_type) Length() const
+  {
+    const char_type* data;
+    return NS_StringGetData(*this, &data);
+  }
+
+  NS_HIDDEN_(bool) IsEmpty() const { return Length() == 0; }
+
+  NS_HIDDEN_(void) SetIsVoid(bool aVal) { NS_StringSetIsVoid(*this, aVal); }
+  NS_HIDDEN_(bool) IsVoid() const { return NS_StringGetIsVoid(*this); }
+
+  NS_HIDDEN_(void) Assign(const self_type& aString)
+  {
+    NS_StringCopy(*this, aString);
+  }
+  NS_HIDDEN_(void) Assign(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_StringSetData(*this, aData, aLength);
+  }
+  NS_HIDDEN_(void) Assign(char_type aChar)
+  {
+    NS_StringSetData(*this, &aChar, 1);
+  }
+#ifdef MOZ_USE_CHAR16_WRAPPER
+  NS_HIDDEN_(void) Assign(char16ptr_t aData, size_type aLength = UINT32_MAX)
+  {
+    NS_StringSetData(*this, aData, aLength);
+  }
+#endif
+
+  NS_HIDDEN_(void) AssignLiteral(const char* aStr);
+  NS_HIDDEN_(void) AssignASCII(const char* aStr)
+  {
+    AssignLiteral(aStr);
+  }
+
+  NS_HIDDEN_(self_type&) operator=(const self_type& aString)
+  {
+    Assign(aString);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator=(const char_type* aPtr)
+  {
+    Assign(aPtr);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator=(char_type aChar)
+  {
+    Assign(aChar);
+    return *this;
+  }
+#ifdef MOZ_USE_CHAR16_WRAPPER
+  NS_HIDDEN_(self_type&) operator=(char16ptr_t aPtr)
+  {
+    Assign(aPtr);
+    return *this;
+  }
+#endif
+
+  NS_HIDDEN_(void) Replace(index_type aCutStart, size_type aCutLength,
+                           const char_type* aData,
+                           size_type aLength = size_type(-1))
+  {
+    NS_StringSetDataRange(*this, aCutStart, aCutLength, aData, aLength);
+  }
+  NS_HIDDEN_(void) Replace(index_type aCutStart, size_type aCutLength,
+                           char_type aChar)
+  {
+    Replace(aCutStart, aCutLength, &aChar, 1);
+  }
+  NS_HIDDEN_(void) Replace(index_type aCutStart, size_type aCutLength,
+                           const self_type& aReadable)
+  {
+    const char_type* data;
+    uint32_t dataLen = NS_StringGetData(aReadable, &data);
+    NS_StringSetDataRange(*this, aCutStart, aCutLength, data, dataLen);
+  }
+  NS_HIDDEN_(void) SetCharAt(char_type aChar, index_type aPos)
+  {
+    Replace(aPos, 1, &aChar, 1);
+  }
+
+  NS_HIDDEN_(void) Append(char_type aChar)
+  {
+    Replace(size_type(-1), 0, aChar);
+  }
+  NS_HIDDEN_(void) Append(const char_type* aData,
+                          size_type aLength = size_type(-1))
+  {
+    Replace(size_type(-1), 0, aData, aLength);
+  }
+#ifdef MOZ_USE_CHAR16_WRAPPER
+  NS_HIDDEN_(void) Append(char16ptr_t aData, size_type aLength = size_type(-1))
+  {
+    Append(static_cast<const char16_t*>(aData), aLength);
+  }
+#endif
+  NS_HIDDEN_(void) Append(const self_type& aReadable)
+  {
+    Replace(size_type(-1), 0, aReadable);
+  }
+  NS_HIDDEN_(void) AppendLiteral(const char* aASCIIStr);
+  NS_HIDDEN_(void) AppendASCII(const char* aASCIIStr)
+  {
+    AppendLiteral(aASCIIStr);
+  }
+
+  NS_HIDDEN_(self_type&) operator+=(char_type aChar)
+  {
+    Append(aChar);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator+=(const char_type* aData)
+  {
+    Append(aData);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator+=(const self_type& aReadable)
+  {
+    Append(aReadable);
+    return *this;
+  }
+
+  NS_HIDDEN_(void) Insert(char_type aChar, index_type aPos)
+  {
+    Replace(aPos, 0, aChar);
+  }
+  NS_HIDDEN_(void) Insert(const char_type* aData, index_type aPos,
+                          size_type aLength = size_type(-1))
+  {
+    Replace(aPos, 0, aData, aLength);
+  }
+  NS_HIDDEN_(void) Insert(const self_type& aReadable, index_type aPos)
+  {
+    Replace(aPos, 0, aReadable);
+  }
+
+  NS_HIDDEN_(void) Cut(index_type aCutStart, size_type aCutLength)
+  {
+    Replace(aCutStart, aCutLength, nullptr, 0);
+  }
+
+  NS_HIDDEN_(void) Truncate(size_type aNewLength = 0)
+  {
+    NS_ASSERTION(aNewLength <= Length(), "Truncate cannot make string longer");
+    SetLength(aNewLength);
+  }
+
+  /**
+   * Remove all occurences of characters in aSet from the string.
+   */
+  NS_HIDDEN_(void) StripChars(const char* aSet);
+
+  /**
+   * Strip whitespace characters from the string.
+   */
+  NS_HIDDEN_(void) StripWhitespace() { StripChars("\b\t\r\n "); }
+
+  NS_HIDDEN_(void) Trim(const char* aSet, bool aLeading = true,
+                        bool aTrailing = true);
+
+  /**
+   * Compare strings of characters. Return 0 if the characters are equal,
+   */
+  typedef int32_t (*ComparatorFunc)(const char_type* aStrA,
+                                    const char_type* aStrB,
+                                    uint32_t aLength);
+
+  static NS_HIDDEN_(int32_t) DefaultComparator(const char_type* aStrA,
+                                               const char_type* aStrB,
+                                               uint32_t aLength);
+
+  NS_HIDDEN_(int32_t) Compare(const char_type* aOther,
+                              ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(int32_t) Compare(const self_type& aOther,
+                              ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(bool) Equals(const char_type* aOther,
+                          ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(bool) Equals(const self_type& aOther,
+                          ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(bool) operator<(const self_type& aOther) const
+  {
+    return Compare(aOther) < 0;
+  }
+  NS_HIDDEN_(bool) operator<(const char_type* aOther) const
+  {
+    return Compare(aOther) < 0;
+  }
+
+  NS_HIDDEN_(bool) operator<=(const self_type& aOther) const
+  {
+    return Compare(aOther) <= 0;
+  }
+  NS_HIDDEN_(bool) operator<=(const char_type* aOther) const
+  {
+    return Compare(aOther) <= 0;
+  }
+
+  NS_HIDDEN_(bool) operator==(const self_type& aOther) const
+  {
+    return Equals(aOther);
+  }
+  NS_HIDDEN_(bool) operator==(const char_type* aOther) const
+  {
+    return Equals(aOther);
+  }
+#ifdef MOZ_USE_CHAR16_WRAPPER
+  NS_HIDDEN_(bool) operator==(char16ptr_t aOther) const
+  {
+    return Equals(aOther);
+  }
+#endif
+
+  NS_HIDDEN_(bool) operator>=(const self_type& aOther) const
+  {
+    return Compare(aOther) >= 0;
+  }
+  NS_HIDDEN_(bool) operator>=(const char_type* aOther) const
+  {
+    return Compare(aOther) >= 0;
+  }
+
+  NS_HIDDEN_(bool) operator>(const self_type& aOther) const
+  {
+    return Compare(aOther) > 0;
+  }
+  NS_HIDDEN_(bool) operator>(const char_type* aOther) const
+  {
+    return Compare(aOther) > 0;
+  }
+
+  NS_HIDDEN_(bool) operator!=(const self_type& aOther) const
+  {
+    return !Equals(aOther);
+  }
+  NS_HIDDEN_(bool) operator!=(const char_type* aOther) const
+  {
+    return !Equals(aOther);
+  }
+
+  NS_HIDDEN_(bool) EqualsLiteral(const char* aASCIIString) const;
+  NS_HIDDEN_(bool) EqualsASCII(const char* aASCIIString) const
+  {
+    return EqualsLiteral(aASCIIString);
+  }
+
+  /**
+   * Case-insensitive match this string to a lowercase ASCII string.
+   */
+  NS_HIDDEN_(bool) LowerCaseEqualsLiteral(const char* aASCIIString) const;
+
+  /**
+   * Find the first occurrence of aStr in this string.
+   *
+   * @return the offset of aStr, or -1 if not found
+   */
+  NS_HIDDEN_(int32_t) Find(const self_type& aStr,
+                           ComparatorFunc aComparator = DefaultComparator) const
+  {
+    return Find(aStr, 0, aComparator);
+  }
+
+  /**
+   * Find the first occurrence of aStr in this string, beginning at aOffset.
+   *
+   * @return the offset of aStr, or -1 if not found
+   */
+  NS_HIDDEN_(int32_t) Find(const self_type& aStr, uint32_t aOffset,
+                           ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Find an ASCII string within this string.
+   *
+   * @return the offset of aStr, or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) Find(const char* aStr, bool aIgnoreCase = false) const
+  {
+    return Find(aStr, 0, aIgnoreCase);
+  }
+
+  NS_HIDDEN_(int32_t) Find(const char* aStr, uint32_t aOffset,
+                           bool aIgnoreCase = false) const;
+
+  /**
+   * Find the last occurrence of aStr in this string.
+   *
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const self_type& aStr,
+                            ComparatorFunc aComparator = DefaultComparator) const
+  {
+    return RFind(aStr, -1, aComparator);
+  }
+
+  /**
+   * Find the last occurrence of aStr in this string, beginning at aOffset.
+   *
+   * @param aOffset the offset from the beginning of the string to begin
+   *        searching. If aOffset < 0, search from end of this string.
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const self_type& aStr, int32_t aOffset,
+                            ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Find the last occurrence of an ASCII string within this string.
+   *
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const char* aStr, bool aIgnoreCase = false) const
+  {
+    return RFind(aStr, -1, aIgnoreCase);
+  }
+
+  /**
+   * Find the last occurrence of an ASCII string beginning at aOffset.
+   *
+   * @param aOffset the offset from the beginning of the string to begin
+   *        searching. If aOffset < 0, search from end of this string.
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const char* aStr, int32_t aOffset,
+                            bool aIgnoreCase) const;
+
+  /**
+   * Search for the offset of the first occurrence of a character in a
+   * string.
+   *
+   * @param aOffset the offset from the beginning of the string to begin
+   *        searching
+   * @return The offset of the character from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) FindChar(char_type aChar, uint32_t aOffset = 0) const;
+
+  /**
+   * Search for the offset of the last occurrence of a character in a
+   * string.
+   *
+   * @return The offset of the character from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFindChar(char_type aChar) const;
+
+  /**
+   * Append a string representation of a number.
+   */
+  NS_HIDDEN_(void) AppendInt(int aInt, int32_t aRadix = 10);
+
+#ifndef XPCOM_GLUE_AVOID_NSPR
+  /**
+   * Convert this string to an integer.
+   *
+   * @param aErrorCode pointer to contain result code.
+   * @param aRadix must be 10 or 16
+   */
+  NS_HIDDEN_(int32_t) ToInteger(nsresult* aErrorCode,
+                                uint32_t aRadix = 10) const;
+  /**
+   * Convert this string to a 64-bit integer.
+   *
+   * @param aErrorCode pointer to contain result code.
+   * @param aRadix must be 10 or 16
+   */
+  NS_HIDDEN_(int64_t) ToInteger64(nsresult* aErrorCode,
+                                  uint32_t aRadix = 10) const;
+#endif // XPCOM_GLUE_AVOID_NSPR
+
+protected:
+  // Prevent people from allocating a nsAString directly.
+  ~nsAString() {}
+};
+
+class nsACString
+{
+public:
+  typedef char       char_type;
+  typedef nsACString self_type;
+  typedef uint32_t   size_type;
+  typedef uint32_t   index_type;
+
+  /**
+   * Returns the length, beginning, and end of a string in one operation.
+   */
+  NS_HIDDEN_(uint32_t) BeginReading(const char_type** aBegin,
+                                    const char_type** aEnd = nullptr) const;
+
+  NS_HIDDEN_(const char_type*) BeginReading() const;
+  NS_HIDDEN_(const char_type*) EndReading() const;
+
+  NS_HIDDEN_(char_type) CharAt(uint32_t aPos) const
+  {
+    NS_ASSERTION(aPos < Length(), "Out of bounds");
+    return BeginReading()[aPos];
+  }
+  NS_HIDDEN_(char_type) operator [](uint32_t aPos) const
+  {
+    return CharAt(aPos);
+  }
+  NS_HIDDEN_(char_type) First() const
+  {
+    return CharAt(0);
+  }
+  NS_HIDDEN_(char_type) Last() const
+  {
+    const char_type* data;
+    uint32_t dataLen = NS_CStringGetData(*this, &data);
+    return data[dataLen - 1];
+  }
+
+  /**
+   * Get the length, begin writing, and optionally set the length of a
+   * string all in one operation.
+   *
+   * @param   newSize Size the string to this length. Pass UINT32_MAX
+   *                  to leave the length unchanged.
+   * @return  The new length of the string, or 0 if resizing failed.
+   */
+  NS_HIDDEN_(uint32_t) BeginWriting(char_type** aBegin,
+                                    char_type** aEnd = nullptr,
+                                    uint32_t aNewSize = UINT32_MAX);
+
+  NS_HIDDEN_(char_type*) BeginWriting(uint32_t aLen = UINT32_MAX);
+  NS_HIDDEN_(char_type*) EndWriting();
+
+  NS_HIDDEN_(bool) SetLength(uint32_t aLen);
+
+  NS_HIDDEN_(size_type) Length() const
+  {
+    const char_type* data;
+    return NS_CStringGetData(*this, &data);
+  }
+
+  NS_HIDDEN_(bool) IsEmpty() const { return Length() == 0; }
+
+  NS_HIDDEN_(void) SetIsVoid(bool aVal) { NS_CStringSetIsVoid(*this, aVal); }
+  NS_HIDDEN_(bool) IsVoid() const { return NS_CStringGetIsVoid(*this); }
+
+  NS_HIDDEN_(void) Assign(const self_type& aString)
+  {
+    NS_CStringCopy(*this, aString);
+  }
+  NS_HIDDEN_(void) Assign(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_CStringSetData(*this, aData, aLength);
+  }
+  NS_HIDDEN_(void) Assign(char_type aChar)
+  {
+    NS_CStringSetData(*this, &aChar, 1);
+  }
+  NS_HIDDEN_(void) AssignLiteral(const char_type* aData)
+  {
+    Assign(aData);
+  }
+  NS_HIDDEN_(void) AssignASCII(const char_type* aData)
+  {
+    Assign(aData);
+  }
+
+  NS_HIDDEN_(self_type&) operator=(const self_type& aString)
+  {
+    Assign(aString);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator=(const char_type* aPtr)
+  {
+    Assign(aPtr);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator=(char_type aChar)
+  {
+    Assign(aChar);
+    return *this;
+  }
+
+  NS_HIDDEN_(void) Replace(index_type aCutStart, size_type aCutLength,
+                           const char_type* aData,
+                           size_type aLength = size_type(-1))
+  {
+    NS_CStringSetDataRange(*this, aCutStart, aCutLength, aData, aLength);
+  }
+  NS_HIDDEN_(void) Replace(index_type aCutStart, size_type aCutLength,
+                           char_type aChar)
+  {
+    Replace(aCutStart, aCutLength, &aChar, 1);
+  }
+  NS_HIDDEN_(void) Replace(index_type aCutStart, size_type aCutLength,
+                           const self_type& aReadable)
+  {
+    const char_type* data;
+    uint32_t dataLen = NS_CStringGetData(aReadable, &data);
+    NS_CStringSetDataRange(*this, aCutStart, aCutLength, data, dataLen);
+  }
+  NS_HIDDEN_(void) SetCharAt(char_type aChar, index_type aPos)
+  {
+    Replace(aPos, 1, &aChar, 1);
+  }
+
+  NS_HIDDEN_(void) Append(char_type aChar)
+  {
+    Replace(size_type(-1), 0, aChar);
+  }
+  NS_HIDDEN_(void) Append(const char_type* aData,
+                          size_type aLength = size_type(-1))
+  {
+    Replace(size_type(-1), 0, aData, aLength);
+  }
+  NS_HIDDEN_(void) Append(const self_type& aReadable)
+  {
+    Replace(size_type(-1), 0, aReadable);
+  }
+  NS_HIDDEN_(void) AppendLiteral(const char* aASCIIStr)
+  {
+    Append(aASCIIStr);
+  }
+  NS_HIDDEN_(void) AppendASCII(const char* aASCIIStr)
+  {
+    Append(aASCIIStr);
+  }
+
+  NS_HIDDEN_(self_type&) operator+=(char_type aChar)
+  {
+    Append(aChar);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator+=(const char_type* aData)
+  {
+    Append(aData);
+    return *this;
+  }
+  NS_HIDDEN_(self_type&) operator+=(const self_type& aReadable)
+  {
+    Append(aReadable);
+    return *this;
+  }
+
+  NS_HIDDEN_(void) Insert(char_type aChar, index_type aPos)
+  {
+    Replace(aPos, 0, aChar);
+  }
+  NS_HIDDEN_(void) Insert(const char_type* aData, index_type aPos,
+                          size_type aLength = size_type(-1))
+  {
+    Replace(aPos, 0, aData, aLength);
+  }
+  NS_HIDDEN_(void) Insert(const self_type& aReadable, index_type aPos)
+  {
+    Replace(aPos, 0, aReadable);
+  }
+
+  NS_HIDDEN_(void) Cut(index_type aCutStart, size_type aCutLength)
+  {
+    Replace(aCutStart, aCutLength, nullptr, 0);
+  }
+
+  NS_HIDDEN_(void) Truncate(size_type aNewLength = 0)
+  {
+    NS_ASSERTION(aNewLength <= Length(), "Truncate cannot make string longer");
+    SetLength(aNewLength);
+  }
+
+  /**
+   * Remove all occurences of characters in aSet from the string.
+   */
+  NS_HIDDEN_(void) StripChars(const char* aSet);
+
+  /**
+   * Strip whitespace characters from the string.
+   */
+  NS_HIDDEN_(void) StripWhitespace() { StripChars("\b\t\r\n "); }
+
+  NS_HIDDEN_(void) Trim(const char* aSet, bool aLeading = true,
+                        bool aTrailing = true);
+
+  /**
+   * Compare strings of characters. Return 0 if the characters are equal,
+   */
+  typedef int32_t (*ComparatorFunc)(const char_type* a,
+                                    const char_type* b,
+                                    uint32_t length);
+
+  static NS_HIDDEN_(int32_t) DefaultComparator(const char_type* aStrA,
+                                               const char_type* aStrB,
+                                               uint32_t aLength);
+
+  NS_HIDDEN_(int32_t) Compare(const char_type* aOther,
+                              ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(int32_t) Compare(const self_type& aOther,
+                              ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(bool) Equals(const char_type* aOther,
+                          ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(bool) Equals(const self_type& aOther,
+                          ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(bool) operator<(const self_type& aOther) const
+  {
+    return Compare(aOther) < 0;
+  }
+  NS_HIDDEN_(bool) operator<(const char_type* aOther) const
+  {
+    return Compare(aOther) < 0;
+  }
+
+  NS_HIDDEN_(bool) operator<=(const self_type& aOther) const
+  {
+    return Compare(aOther) <= 0;
+  }
+  NS_HIDDEN_(bool) operator<=(const char_type* aOther) const
+  {
+    return Compare(aOther) <= 0;
+  }
+
+  NS_HIDDEN_(bool) operator==(const self_type& aOther) const
+  {
+    return Equals(aOther);
+  }
+  NS_HIDDEN_(bool) operator==(const char_type* aOther) const
+  {
+    return Equals(aOther);
+  }
+
+  NS_HIDDEN_(bool) operator>=(const self_type& aOther) const
+  {
+    return Compare(aOther) >= 0;
+  }
+  NS_HIDDEN_(bool) operator>=(const char_type* aOther) const
+  {
+    return Compare(aOther) >= 0;
+  }
+
+  NS_HIDDEN_(bool) operator>(const self_type& aOther) const
+  {
+    return Compare(aOther) > 0;
+  }
+  NS_HIDDEN_(bool) operator>(const char_type* aOther) const
+  {
+    return Compare(aOther) > 0;
+  }
+
+  NS_HIDDEN_(bool) operator!=(const self_type& aOther) const
+  {
+    return !Equals(aOther);
+  }
+  NS_HIDDEN_(bool) operator!=(const char_type* aOther) const
+  {
+    return !Equals(aOther);
+  }
+
+  NS_HIDDEN_(bool) EqualsLiteral(const char_type* aOther) const
+  {
+    return Equals(aOther);
+  }
+  NS_HIDDEN_(bool) EqualsASCII(const char_type* aOther) const
+  {
+    return Equals(aOther);
+  }
+
+  /**
+   * Case-insensitive match this string to a lowercase ASCII string.
+   */
+  NS_HIDDEN_(bool) LowerCaseEqualsLiteral(const char* aASCIIString) const
+  {
+    return Equals(aASCIIString, CaseInsensitiveCompare);
+  }
+
+  /**
+   * Find the first occurrence of aStr in this string.
+   *
+   * @return the offset of aStr, or -1 if not found
+   */
+  NS_HIDDEN_(int32_t) Find(const self_type& aStr,
+                           ComparatorFunc aComparator = DefaultComparator) const
+  {
+    return Find(aStr, 0, aComparator);
+  }
+
+  /**
+   * Find the first occurrence of aStr in this string, beginning at aOffset.
+   *
+   * @return the offset of aStr, or -1 if not found
+   */
+  NS_HIDDEN_(int32_t) Find(const self_type& aStr, uint32_t aOffset,
+                           ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Find the first occurrence of aStr in this string.
+   *
+   * @return the offset of aStr, or -1 if not found
+   */
+  NS_HIDDEN_(int32_t) Find(const char_type* aStr,
+                           ComparatorFunc aComparator = DefaultComparator) const;
+
+  NS_HIDDEN_(int32_t) Find(const char_type* aStr, uint32_t aLen,
+                           ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Find the last occurrence of aStr in this string.
+   *
+   * @return The offset of the character from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const self_type& aStr,
+                            ComparatorFunc aComparator = DefaultComparator) const
+  {
+    return RFind(aStr, -1, aComparator);
+  }
+
+  /**
+   * Find the last occurrence of aStr in this string, beginning at aOffset.
+   *
+   * @param aOffset the offset from the beginning of the string to begin
+   *        searching. If aOffset < 0, search from end of this string.
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const self_type& aStr, int32_t aOffset,
+                            ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Find the last occurrence of aStr in this string.
+   *
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const char_type* aStr,
+                            ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Find the last occurrence of an ASCII string in this string,
+   * beginning at aOffset.
+   *
+   * @param aLen is the length of aStr
+   * @return The offset of aStr from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFind(const char_type* aStr, int32_t aLen,
+                            ComparatorFunc aComparator = DefaultComparator) const;
+
+  /**
+   * Search for the offset of the first occurrence of a character in a
+   * string.
+   *
+   * @param aOffset the offset from the beginning of the string to begin
+   *        searching
+   * @return The offset of the character from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) FindChar(char_type aChar, uint32_t aOffset = 0) const;
+
+  /**
+   * Search for the offset of the last occurrence of a character in a
+   * string.
+   *
+   * @return The offset of the character from the beginning of the string,
+   *         or -1 if not found.
+   */
+  NS_HIDDEN_(int32_t) RFindChar(char_type aChar) const;
+
+  /**
+   * Append a string representation of a number.
+   */
+  NS_HIDDEN_(void) AppendInt(int aInt, int32_t aRadix = 10);
+
+#ifndef XPCOM_GLUE_AVOID_NSPR
+  /**
+   * Convert this string to an integer.
+   *
+   * @param aErrorCode pointer to contain result code.
+   * @param aRadix must be 10 or 16
+   */
+  NS_HIDDEN_(int32_t) ToInteger(nsresult* aErrorCode,
+                                uint32_t aRadix = 10) const;
+  /**
+   * Convert this string to a 64-bit integer.
+   *
+   * @param aErrorCode pointer to contain result code.
+   * @param aRadix must be 10 or 16
+   */
+  NS_HIDDEN_(int64_t) ToInteger64(nsresult* aErrorCode,
+                                  uint32_t aRadix = 10) const;
+#endif // XPCOM_GLUE_AVOID_NSPR
+
+protected:
+  // Prevent people from allocating a nsAString directly.
+  ~nsACString() {}
+};
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Below we define nsStringContainer and nsCStringContainer.  These classes
+ * have unspecified structure.  In most cases, your code should use
+ * nsString/nsCString instead of these classes; if you prefer C-style
+ * programming, then look no further.
+ */
+
+class nsStringContainer
+  : public nsAString
+  , private nsStringContainer_base
+{
+};
+
+class nsCStringContainer
+  : public nsACString
+  , private nsStringContainer_base
+{
+};
+
+/**
+ * The following classes are C++ helper classes that make the frozen string
+ * API easier to use.
+ */
+
+/**
+ * Rename symbols to avoid conflicting with internal versions.
+ */
+#define nsString                       nsString_external
+#define nsCString                      nsCString_external
+#define nsDependentString              nsDependentString_external
+#define nsDependentCString             nsDependentCString_external
+#define NS_ConvertASCIItoUTF16         NS_ConvertASCIItoUTF16_external
+#define NS_ConvertUTF8toUTF16          NS_ConvertUTF8toUTF16_external
+#define NS_ConvertUTF16toUTF8          NS_ConvertUTF16toUTF8_external
+#define NS_LossyConvertUTF16toASCII    NS_LossyConvertUTF16toASCII_external
+#define nsGetterCopies                 nsGetterCopies_external
+#define nsCGetterCopies                nsCGetterCopies_external
+#define nsDependentSubstring           nsDependentSubstring_external
+#define nsDependentCSubstring          nsDependentCSubstring_external
+
+/**
+ * basic strings
+ */
+
+class nsString : public nsStringContainer
+{
+public:
+  typedef nsString         self_type;
+  typedef nsAString        abstract_string_type;
+
+  nsString()
+  {
+    NS_StringContainerInit(*this);
+  }
+
+  nsString(const self_type& aString)
+  {
+    NS_StringContainerInit(*this);
+    NS_StringCopy(*this, aString);
+  }
+
+  explicit nsString(const abstract_string_type& aReadable)
+  {
+    NS_StringContainerInit(*this);
+    NS_StringCopy(*this, aReadable);
+  }
+
+  explicit nsString(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_StringContainerInit2(*this, aData, aLength, 0);
+  }
+
+#ifdef MOZ_USE_CHAR16_WRAPPER
+  explicit nsString(char16ptr_t aData, size_type aLength = UINT32_MAX)
+    : nsString(static_cast<const char16_t*>(aData), aLength)
+  {
+  }
+#endif
+
+  ~nsString()
+  {
+    NS_StringContainerFinish(*this);
+  }
+
+  char16ptr_t get() const
+  {
+    return char16ptr_t(BeginReading());
+  }
+
+  self_type& operator=(const self_type& aString)
+  {
+    Assign(aString);
+    return *this;
+  }
+  self_type& operator=(const abstract_string_type& aReadable)
+  {
+    Assign(aReadable);
+    return *this;
+  }
+  self_type& operator=(const char_type* aPtr)
+  {
+    Assign(aPtr);
+    return *this;
+  }
+  self_type& operator=(char_type aChar)
+  {
+    Assign(aChar);
+    return *this;
+  }
+
+  void Adopt(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_StringContainerFinish(*this);
+    NS_StringContainerInit2(*this, aData, aLength,
+                            NS_STRING_CONTAINER_INIT_ADOPT);
+  }
+
+protected:
+  nsString(const char_type* aData, size_type aLength, uint32_t aFlags)
+  {
+    NS_StringContainerInit2(*this, aData, aLength, aFlags);
+  }
+};
+
+class nsCString : public nsCStringContainer
+{
+public:
+  typedef nsCString        self_type;
+  typedef nsACString       abstract_string_type;
+
+  nsCString()
+  {
+    NS_CStringContainerInit(*this);
+  }
+
+  nsCString(const self_type& aString)
+  {
+    NS_CStringContainerInit(*this);
+    NS_CStringCopy(*this, aString);
+  }
+
+  explicit nsCString(const abstract_string_type& aReadable)
+  {
+    NS_CStringContainerInit(*this);
+    NS_CStringCopy(*this, aReadable);
+  }
+
+  explicit nsCString(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_CStringContainerInit(*this);
+    NS_CStringSetData(*this, aData, aLength);
+  }
+
+  ~nsCString()
+  {
+    NS_CStringContainerFinish(*this);
+  }
+
+  const char_type* get() const
+  {
+    return BeginReading();
+  }
+
+  self_type& operator=(const self_type& aString)
+  {
+    Assign(aString);
+    return *this;
+  }
+  self_type& operator=(const abstract_string_type& aReadable)
+  {
+    Assign(aReadable);
+    return *this;
+  }
+  self_type& operator=(const char_type* aPtr)
+  {
+    Assign(aPtr);
+    return *this;
+  }
+  self_type& operator=(char_type aChar)
+  {
+    Assign(aChar);
+    return *this;
+  }
+
+  void Adopt(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_CStringContainerFinish(*this);
+    NS_CStringContainerInit2(*this, aData, aLength,
+                             NS_CSTRING_CONTAINER_INIT_ADOPT);
+  }
+
+protected:
+  nsCString(const char_type* aData, size_type aLength, uint32_t aFlags)
+  {
+    NS_CStringContainerInit2(*this, aData, aLength, aFlags);
+  }
+};
+
+
+/**
+ * dependent strings
+ */
+
+class nsDependentString : public nsString
+{
+public:
+  typedef nsDependentString         self_type;
+
+  nsDependentString() {}
+
+  explicit nsDependentString(const char_type* aData,
+                             size_type aLength = UINT32_MAX)
+    : nsString(aData, aLength, NS_CSTRING_CONTAINER_INIT_DEPEND)
+  {
+  }
+
+#ifdef MOZ_USE_CHAR16_WRAPPER
+  explicit nsDependentString(char16ptr_t aData, size_type aLength = UINT32_MAX)
+    : nsDependentString(static_cast<const char16_t*>(aData), aLength)
+  {
+  }
+#endif
+
+  void Rebind(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_StringContainerFinish(*this);
+    NS_StringContainerInit2(*this, aData, aLength,
+                            NS_STRING_CONTAINER_INIT_DEPEND);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+class nsDependentCString : public nsCString
+{
+public:
+  typedef nsDependentCString        self_type;
+
+  nsDependentCString() {}
+
+  explicit nsDependentCString(const char_type* aData,
+                              size_type aLength = UINT32_MAX)
+    : nsCString(aData, aLength, NS_CSTRING_CONTAINER_INIT_DEPEND)
+  {
+  }
+
+  void Rebind(const char_type* aData, size_type aLength = UINT32_MAX)
+  {
+    NS_CStringContainerFinish(*this);
+    NS_CStringContainerInit2(*this, aData, aLength,
+                             NS_CSTRING_CONTAINER_INIT_DEPEND);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+
+/**
+ * conversion classes
+ */
+
+inline void
+CopyUTF16toUTF8(const nsAString& aSource, nsACString& aDest)
+{
+  NS_UTF16ToCString(aSource, NS_CSTRING_ENCODING_UTF8, aDest);
+}
+
+inline void
+CopyUTF8toUTF16(const nsACString& aSource, nsAString& aDest)
+{
+  NS_CStringToUTF16(aSource, NS_CSTRING_ENCODING_UTF8, aDest);
+}
+
+inline void
+LossyCopyUTF16toASCII(const nsAString& aSource, nsACString& aDest)
+{
+  NS_UTF16ToCString(aSource, NS_CSTRING_ENCODING_ASCII, aDest);
+}
+
+inline void
+CopyASCIItoUTF16(const nsACString& aSource, nsAString& aDest)
+{
+  NS_CStringToUTF16(aSource, NS_CSTRING_ENCODING_ASCII, aDest);
+}
+
+char*
+ToNewUTF8String(const nsAString& aSource);
+
+class NS_ConvertASCIItoUTF16 : public nsString
+{
+public:
+  typedef NS_ConvertASCIItoUTF16    self_type;
+
+  explicit NS_ConvertASCIItoUTF16(const nsACString& aStr)
+  {
+    NS_CStringToUTF16(aStr, NS_CSTRING_ENCODING_ASCII, *this);
+  }
+
+  explicit NS_ConvertASCIItoUTF16(const char* aData,
+                                  uint32_t aLength = UINT32_MAX)
+  {
+    NS_CStringToUTF16(nsDependentCString(aData, aLength),
+                      NS_CSTRING_ENCODING_ASCII, *this);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+class NS_ConvertUTF8toUTF16 : public nsString
+{
+public:
+  typedef NS_ConvertUTF8toUTF16    self_type;
+
+  explicit NS_ConvertUTF8toUTF16(const nsACString& aStr)
+  {
+    NS_CStringToUTF16(aStr, NS_CSTRING_ENCODING_UTF8, *this);
+  }
+
+  explicit NS_ConvertUTF8toUTF16(const char* aData,
+                                 uint32_t aLength = UINT32_MAX)
+  {
+    NS_CStringToUTF16(nsDependentCString(aData, aLength),
+                      NS_CSTRING_ENCODING_UTF8, *this);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+class NS_ConvertUTF16toUTF8 : public nsCString
+{
+public:
+  typedef NS_ConvertUTF16toUTF8    self_type;
+
+  explicit NS_ConvertUTF16toUTF8(const nsAString& aStr)
+  {
+    NS_UTF16ToCString(aStr, NS_CSTRING_ENCODING_UTF8, *this);
+  }
+
+  explicit NS_ConvertUTF16toUTF8(const char16ptr_t aData,
+                                 uint32_t aLength = UINT32_MAX)
+  {
+    NS_UTF16ToCString(nsDependentString(aData, aLength),
+                      NS_CSTRING_ENCODING_UTF8, *this);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+class NS_LossyConvertUTF16toASCII : public nsCString
+{
+public:
+  typedef NS_LossyConvertUTF16toASCII    self_type;
+
+  explicit NS_LossyConvertUTF16toASCII(const nsAString& aStr)
+  {
+    NS_UTF16ToCString(aStr, NS_CSTRING_ENCODING_ASCII, *this);
+  }
+
+  explicit NS_LossyConvertUTF16toASCII(const char16ptr_t aData,
+                                       uint32_t aLength = UINT32_MAX)
+  {
+    NS_UTF16ToCString(nsDependentString(aData, aLength),
+                      NS_CSTRING_ENCODING_ASCII, *this);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+
+/**
+ * literal strings
+ */
+static_assert(sizeof(char16_t) == 2, "size of char16_t must be 2");
+static_assert(char16_t(-1) > char16_t(0), "char16_t must be unsigned");
+
+#define NS_MULTILINE_LITERAL_STRING(s) \
+  nsDependentString(reinterpret_cast<const nsAString::char_type*>(s), \
+                    uint32_t((sizeof(s) / 2) - 1))
+#define NS_MULTILINE_LITERAL_STRING_INIT(n, s) \
+  n(reinterpret_cast<const nsAString::char_type*>(s), \
+    uint32_t((sizeof(s) / 2) - 1))
+#define NS_NAMED_MULTILINE_LITERAL_STRING(n,s) \
+  const nsDependentString n(reinterpret_cast<const nsAString::char_type*>(s), \
+                            uint32_t((sizeof(s) / 2) - 1))
+typedef nsDependentString nsLiteralString;
+
+#define NS_LITERAL_STRING(s) \
+  static_cast<const nsString&>(NS_MULTILINE_LITERAL_STRING(u"" s))
+#define NS_LITERAL_STRING_INIT(n, s) \
+  NS_MULTILINE_LITERAL_STRING_INIT(n, (u"" s))
+#define NS_NAMED_LITERAL_STRING(n, s) \
+  NS_NAMED_MULTILINE_LITERAL_STRING(n, (u"" s))
+
+#define NS_LITERAL_CSTRING(s) \
+  static_cast<const nsDependentCString&>(nsDependentCString(s, uint32_t(sizeof(s) - 1)))
+#define NS_LITERAL_CSTRING_INIT(n, s) \
+  n(s, uint32_t(sizeof(s)-1))
+#define NS_NAMED_LITERAL_CSTRING(n, s) \
+  const nsDependentCString n(s, uint32_t(sizeof(s)-1))
+
+typedef nsDependentCString nsLiteralCString;
+
+
+/**
+ * getter_Copies support
+ *
+ *    NS_IMETHOD GetBlah(char16_t**);
+ *
+ *    void some_function()
+ *    {
+ *      nsString blah;
+ *      GetBlah(getter_Copies(blah));
+ *      // ...
+ *    }
+ */
+
+class nsGetterCopies
+{
+public:
+  typedef char16_t char_type;
+
+  explicit nsGetterCopies(nsString& aStr)
+    : mString(aStr)
+    , mData(nullptr)
+  {
+  }
+
+  ~nsGetterCopies() { mString.Adopt(mData); }
+
+  operator char_type**() { return &mData; }
+
+private:
+  nsString&  mString;
+  char_type* mData;
+};
+
+inline nsGetterCopies
+getter_Copies(nsString& aString)
+{
+  return nsGetterCopies(aString);
+}
+
+class nsCGetterCopies
+{
+public:
+  typedef char char_type;
+
+  explicit nsCGetterCopies(nsCString& aStr)
+    : mString(aStr)
+    , mData(nullptr)
+  {
+  }
+
+  ~nsCGetterCopies() { mString.Adopt(mData); }
+
+  operator char_type**() { return &mData; }
+
+private:
+  nsCString& mString;
+  char_type* mData;
+};
+
+inline nsCGetterCopies
+getter_Copies(nsCString& aString)
+{
+  return nsCGetterCopies(aString);
+}
+
+
+/**
+* substrings
+*/
+
+class nsDependentSubstring : public nsStringContainer
+{
+public:
+  typedef nsDependentSubstring self_type;
+  typedef nsAString            abstract_string_type;
+
+  ~nsDependentSubstring() { NS_StringContainerFinish(*this); }
+  nsDependentSubstring() { NS_StringContainerInit(*this); }
+
+  nsDependentSubstring(const char_type* aStart, uint32_t aLength)
+  {
+    NS_StringContainerInit2(*this, aStart, aLength,
+                            NS_STRING_CONTAINER_INIT_DEPEND |
+                            NS_STRING_CONTAINER_INIT_SUBSTRING);
+  }
+
+  nsDependentSubstring(const abstract_string_type& aStr,
+                       uint32_t aStartPos);
+  nsDependentSubstring(const abstract_string_type& aStr,
+                       uint32_t aStartPos, uint32_t aLength);
+
+  void Rebind(const char_type* aStart, uint32_t aLength)
+  {
+    NS_StringContainerFinish(*this);
+    NS_StringContainerInit2(*this, aStart, aLength,
+                            NS_STRING_CONTAINER_INIT_DEPEND |
+                            NS_STRING_CONTAINER_INIT_SUBSTRING);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+class nsDependentCSubstring : public nsCStringContainer
+{
+public:
+  typedef nsDependentCSubstring self_type;
+  typedef nsACString            abstract_string_type;
+
+  ~nsDependentCSubstring() { NS_CStringContainerFinish(*this); }
+  nsDependentCSubstring() { NS_CStringContainerInit(*this); }
+
+  nsDependentCSubstring(const char_type* aStart, uint32_t aLength)
+  {
+    NS_CStringContainerInit2(*this, aStart, aLength,
+                             NS_CSTRING_CONTAINER_INIT_DEPEND |
+                             NS_CSTRING_CONTAINER_INIT_SUBSTRING);
+  }
+
+  nsDependentCSubstring(const abstract_string_type& aStr,
+                        uint32_t aStartPos);
+  nsDependentCSubstring(const abstract_string_type& aStr,
+                        uint32_t aStartPos, uint32_t aLength);
+
+  void Rebind(const char_type* aStart, uint32_t aLength)
+  {
+    NS_CStringContainerFinish(*this);
+    NS_CStringContainerInit2(*this, aStart, aLength,
+                             NS_CSTRING_CONTAINER_INIT_DEPEND |
+                             NS_CSTRING_CONTAINER_INIT_SUBSTRING);
+  }
+
+private:
+  self_type& operator=(const self_type& aString) = delete;
+};
+
+
+/**
+ * Various nsDependentC?Substring constructor functions
+ */
+
+// char16_t
+inline const nsDependentSubstring
+Substring(const nsAString& aStr, uint32_t aStartPos)
+{
+  return nsDependentSubstring(aStr, aStartPos);
+}
+
+inline const nsDependentSubstring
+Substring(const nsAString& aStr, uint32_t aStartPos, uint32_t aLength)
+{
+  return nsDependentSubstring(aStr, aStartPos, aLength);
+}
+
+inline const nsDependentSubstring
+Substring(const char16_t* aStart, const char16_t* aEnd)
+{
+  MOZ_ASSERT(uint32_t(aEnd - aStart) == uintptr_t(aEnd - aStart),
+             "string too long");
+  return nsDependentSubstring(aStart, uint32_t(aEnd - aStart));
+}
+
+inline const nsDependentSubstring
+Substring(const char16_t* aStart, uint32_t aLength)
+{
+  return nsDependentSubstring(aStart, aLength);
+}
+
+inline const nsDependentSubstring
+StringHead(const nsAString& aStr, uint32_t aCount)
+{
+  return nsDependentSubstring(aStr, 0, aCount);
+}
+
+inline const nsDependentSubstring
+StringTail(const nsAString& aStr, uint32_t aCount)
+{
+  return nsDependentSubstring(aStr, aStr.Length() - aCount, aCount);
+}
+
+// char
+inline const nsDependentCSubstring
+Substring(const nsACString& aStr, uint32_t aStartPos)
+{
+  return nsDependentCSubstring(aStr, aStartPos);
+}
+
+inline const nsDependentCSubstring
+Substring(const nsACString& aStr, uint32_t aStartPos, uint32_t aLength)
+{
+  return nsDependentCSubstring(aStr, aStartPos, aLength);
+}
+
+inline const nsDependentCSubstring
+Substring(const char* aStart, const char* aEnd)
+{
+  MOZ_ASSERT(uint32_t(aEnd - aStart) == uintptr_t(aEnd - aStart),
+             "string too long");
+  return nsDependentCSubstring(aStart, uint32_t(aEnd - aStart));
+}
+
+inline const nsDependentCSubstring
+Substring(const char* aStart, uint32_t aLength)
+{
+  return nsDependentCSubstring(aStart, aLength);
+}
+
+inline const nsDependentCSubstring
+StringHead(const nsACString& aStr, uint32_t aCount)
+{
+  return nsDependentCSubstring(aStr, 0, aCount);
+}
+
+inline const nsDependentCSubstring
+StringTail(const nsACString& aStr, uint32_t aCount)
+{
+  return nsDependentCSubstring(aStr, aStr.Length() - aCount, aCount);
+}
+
+
+inline bool
+StringBeginsWith(const nsAString& aSource, const nsAString& aSubstring,
+                 nsAString::ComparatorFunc aComparator = nsAString::DefaultComparator)
+{
+  return aSubstring.Length() <= aSource.Length() &&
+    StringHead(aSource, aSubstring.Length()).Equals(aSubstring, aComparator);
+}
+
+inline bool
+StringEndsWith(const nsAString& aSource, const nsAString& aSubstring,
+               nsAString::ComparatorFunc aComparator = nsAString::DefaultComparator)
+{
+  return aSubstring.Length() <= aSource.Length() &&
+    StringTail(aSource, aSubstring.Length()).Equals(aSubstring, aComparator);
+}
+
+inline bool
+StringBeginsWith(const nsACString& aSource, const nsACString& aSubstring,
+                 nsACString::ComparatorFunc aComparator = nsACString::DefaultComparator)
+{
+  return aSubstring.Length() <= aSource.Length() &&
+    StringHead(aSource, aSubstring.Length()).Equals(aSubstring, aComparator);
+}
+
+inline bool
+StringEndsWith(const nsACString& aSource, const nsACString& aSubstring,
+               nsACString::ComparatorFunc aComparator = nsACString::DefaultComparator)
+{
+  return aSubstring.Length() <= aSource.Length() &&
+    StringTail(aSource, aSubstring.Length()).Equals(aSubstring, aComparator);
+}
+
+/**
+ * Trim whitespace from the beginning and end of a string; then compress
+ * remaining runs of whitespace characters to a single space.
+ */
+NS_HIDDEN_(void) CompressWhitespace(nsAString& aString);
+
+#define EmptyCString() nsCString()
+#define EmptyString() nsString()
+
+/**
+ * Convert an ASCII string to all upper/lowercase (a-z,A-Z only). As a bonus,
+ * returns the string length.
+ */
+NS_HIDDEN_(uint32_t) ToLowerCase(nsACString& aStr);
+
+NS_HIDDEN_(uint32_t) ToUpperCase(nsACString& aStr);
+
+NS_HIDDEN_(uint32_t) ToLowerCase(const nsACString& aSrc, nsACString& aDest);
+
+NS_HIDDEN_(uint32_t) ToUpperCase(const nsACString& aSrc, nsACString& aDest);
+
+/**
+ * The following declarations are *deprecated*, and are included here only
+ * to make porting from existing code that doesn't use the frozen string API
+ * easier. They may disappear in the future.
+ */
+
+inline char*
+ToNewCString(const nsACString& aStr)
+{
+  return NS_CStringCloneData(aStr);
+}
+
+inline char16_t*
+ToNewUnicode(const nsAString& aStr)
+{
+  return NS_StringCloneData(aStr);
+}
+
+typedef nsString PromiseFlatString;
+typedef nsCString PromiseFlatCString;
+
+typedef nsCString nsAutoCString;
+typedef nsString nsAutoString;
+
+NS_HIDDEN_(bool) ParseString(const nsACString& aAstring, char aDelimiter,
+                             nsTArray<nsCString>& aArray);
+
+#endif // nsStringAPI_h__