gecko-dev/dom/xslt/xml/txXMLUtils.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

/*
 * XML utility classes
 */

#include "txXMLUtils.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "nsGkAtoms.h"
#include "txStringUtils.h"
#include "txNamespaceMap.h"
#include "txXPathTreeWalker.h"
#include "nsContentUtils.h"

//------------------------------/
//- Implementation of XMLUtils -/
//------------------------------/

// static
nsresult XMLUtils::splitExpatName(const char16_t* aExpatName, nsAtom** aPrefix,
                                  nsAtom** aLocalName, int32_t* aNameSpaceID) {
  /**
   *  Expat can send the following:
   *    localName
   *    namespaceURI<separator>localName
   *    namespaceURI<separator>localName<separator>prefix
   */

  const char16_t* uriEnd = nullptr;
  const char16_t* nameEnd = nullptr;
  const char16_t* pos;
  for (pos = aExpatName; *pos; ++pos) {
    if (*pos == kExpatSeparatorChar) {
      if (uriEnd) {
        nameEnd = pos;
      } else {
        uriEnd = pos;
      }
    }
  }

  const char16_t* nameStart;
  if (uriEnd) {
    *aNameSpaceID = txNamespaceManager::getNamespaceID(
        nsDependentSubstring(aExpatName, uriEnd));
    if (*aNameSpaceID == kNameSpaceID_Unknown) {
      return NS_ERROR_FAILURE;
    }

    nameStart = (uriEnd + 1);
    if (nameEnd) {
      const char16_t* prefixStart = nameEnd + 1;
      *aPrefix = NS_Atomize(Substring(prefixStart, pos)).take();
      if (!*aPrefix) {
        return NS_ERROR_OUT_OF_MEMORY;
      }
    } else {
      nameEnd = pos;
      *aPrefix = nullptr;
    }
  } else {
    *aNameSpaceID = kNameSpaceID_None;
    nameStart = aExpatName;
    nameEnd = pos;
    *aPrefix = nullptr;
  }

  *aLocalName = NS_Atomize(Substring(nameStart, nameEnd)).take();

  return *aLocalName ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
}

nsresult XMLUtils::splitQName(const nsAString& aName, nsAtom** aPrefix,
                              nsAtom** aLocalName) {
  const char16_t* colon;
  bool valid = XMLUtils::isValidQName(aName, &colon);
  if (!valid) {
    return NS_ERROR_FAILURE;
  }

  if (colon) {
    const char16_t* end;
    aName.EndReading(end);

    *aPrefix = NS_Atomize(Substring(aName.BeginReading(), colon)).take();
    *aLocalName = NS_Atomize(Substring(colon + 1, end)).take();
  } else {
    *aPrefix = nullptr;
    *aLocalName = NS_Atomize(aName).take();
  }

  return NS_OK;
}

/**
 * Returns true if the given string has only whitespace characters
 */
bool XMLUtils::isWhitespace(const nsAString& aText) {
  nsString::const_char_iterator start, end;
  aText.BeginReading(start);
  aText.EndReading(end);
  for (; start != end; ++start) {
    if (!isWhitespace(*start)) {
      return false;
    }
  }
  return true;
}

/**
 * Normalizes the value of a XML processing instruction
 **/
void XMLUtils::normalizePIValue(nsAString& piValue) {
  nsAutoString origValue(piValue);
  uint32_t origLength = origValue.Length();
  uint32_t conversionLoop = 0;
  char16_t prevCh = 0;
  piValue.Truncate();

  while (conversionLoop < origLength) {
    char16_t ch = origValue.CharAt(conversionLoop);
    switch (ch) {
      case '>': {
        if (prevCh == '?') {
          piValue.Append(char16_t(' '));
        }
        break;
      }
      default: {
        break;
      }
    }
    piValue.Append(ch);
    prevCh = ch;
    ++conversionLoop;
  }
}

// static
bool XMLUtils::isValidQName(const nsAString& aQName, const char16_t** aColon) {
  return NS_SUCCEEDED(nsContentUtils::CheckQName(aQName, true, aColon));
}

// static
bool XMLUtils::getXMLSpacePreserve(const txXPathNode& aNode) {
  nsAutoString value;
  txXPathTreeWalker walker(aNode);
  do {
    if (walker.getAttr(nsGkAtoms::space, kNameSpaceID_XML, value)) {
      if (TX_StringEqualsAtom(value, nsGkAtoms::preserve)) {
        return true;
      }
      if (TX_StringEqualsAtom(value, nsGkAtoms::_default)) {
        return false;
      }
    }
  } while (walker.moveToParent());

  return false;
}