palemoon27/dom/base/nsXMLContentSerializer.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/. */

/*
 * nsIContentSerializer implementation that can be used with an
 * nsIDocumentEncoder to convert an XML DOM to an XML string that
 * could be parsed into more or less the original DOM.
 */

#ifndef nsXMLContentSerializer_h__
#define nsXMLContentSerializer_h__

#include "mozilla/Attributes.h"
#include "nsIContentSerializer.h"
#include "nsISupportsUtils.h"
#include "nsCOMPtr.h"
#include "nsTArray.h"
#include "nsString.h"

#define kIndentStr NS_LITERAL_STRING("  ")
#define kEndTag NS_LITERAL_STRING("</")

class nsIAtom;
class nsINode;

class nsXMLContentSerializer : public nsIContentSerializer {
 public:
  nsXMLContentSerializer();

  NS_DECL_ISUPPORTS

  NS_IMETHOD Init(uint32_t flags, uint32_t aWrapColumn,
                  const char* aCharSet, bool aIsCopying,
                  bool aRewriteEncodingDeclaration) override;

  NS_IMETHOD AppendText(nsIContent* aText, int32_t aStartOffset,
                        int32_t aEndOffset, nsAString& aStr) override;

  NS_IMETHOD AppendCDATASection(nsIContent* aCDATASection,
                                int32_t aStartOffset, int32_t aEndOffset,
                                nsAString& aStr) override;

  NS_IMETHOD AppendProcessingInstruction(nsIContent* aPI,
                                         int32_t aStartOffset,
                                         int32_t aEndOffset,
                                         nsAString& aStr) override;

  NS_IMETHOD AppendComment(nsIContent* aComment, int32_t aStartOffset,
                           int32_t aEndOffset, nsAString& aStr) override;
  
  NS_IMETHOD AppendDoctype(nsIContent *aDoctype,
                           nsAString& aStr) override;

  NS_IMETHOD AppendElementStart(mozilla::dom::Element* aElement,
                                mozilla::dom::Element* aOriginalElement,
                                nsAString& aStr) override;

  NS_IMETHOD AppendElementEnd(mozilla::dom::Element* aElement,
                              nsAString& aStr) override;

  NS_IMETHOD Flush(nsAString& aStr) override { return NS_OK; }

  NS_IMETHOD AppendDocumentStart(nsIDocument *aDocument,
                                 nsAString& aStr) override;

 protected:
  virtual ~nsXMLContentSerializer();

  /**
   * Appends a char16_t character and increments the column position
   */
  MOZ_MUST_USE
  bool AppendToString(const char16_t aChar,
                      nsAString& aOutputStr);

  /**
   * Appends a nsAString string and increments the column position
   */
  MOZ_MUST_USE
  bool AppendToString(const nsAString& aStr,
                      nsAString& aOutputStr);

  /**
   * Appends a string by replacing all line-endings
   * by mLineBreak, except in the case of raw output.
   * It increments the column position.
   */
  MOZ_MUST_USE
  bool AppendToStringConvertLF(const nsAString& aStr,
                               nsAString& aOutputStr);

  /**
   * Appends a string by wrapping it when necessary.
   * It updates the column position.
   */
  MOZ_MUST_USE
  bool AppendToStringWrapped(const nsASingleFragmentString& aStr,
                             nsAString& aOutputStr);

  /**
   * Appends a string by formating and wrapping it when necessary
   * It updates the column position.
   */
  MOZ_MUST_USE
  bool AppendToStringFormatedWrapped(const nsASingleFragmentString& aStr,
                                     nsAString& aOutputStr);

  // used by AppendToStringWrapped
  MOZ_MUST_USE
  bool AppendWrapped_WhitespaceSequence(
          nsASingleFragmentString::const_char_iterator &aPos,
          const nsASingleFragmentString::const_char_iterator aEnd,
          const nsASingleFragmentString::const_char_iterator aSequenceStart,
          nsAString &aOutputStr);

  // used by AppendToStringFormatedWrapped
  MOZ_MUST_USE
  bool AppendFormatedWrapped_WhitespaceSequence(
          nsASingleFragmentString::const_char_iterator &aPos,
          const nsASingleFragmentString::const_char_iterator aEnd,
          const nsASingleFragmentString::const_char_iterator aSequenceStart,
          bool &aMayIgnoreStartOfLineWhitespaceSequence,
          nsAString &aOutputStr);

  // used by AppendToStringWrapped and AppendToStringFormatedWrapped
  MOZ_MUST_USE
  bool AppendWrapped_NonWhitespaceSequence(
          nsASingleFragmentString::const_char_iterator &aPos,
          const nsASingleFragmentString::const_char_iterator aEnd,
          const nsASingleFragmentString::const_char_iterator aSequenceStart,
          bool &aMayIgnoreStartOfLineWhitespaceSequence,
          bool &aSequenceStartAfterAWhiteSpace,
          nsAString &aOutputStr);

  /**
   * add mLineBreak to the string
   * It updates the column position and other flags.
   */
  MOZ_MUST_USE
  bool AppendNewLineToString(nsAString& aOutputStr);


  /**
   * Appends a string by translating entities
   * It doesn't increment the column position
   */
  MOZ_MUST_USE
  virtual bool AppendAndTranslateEntities(const nsAString& aStr,
                                          nsAString& aOutputStr);

  /**
   * retrieve the text content of the node and append it to the given string
   * It doesn't increment the column position
   */
  nsresult AppendTextData(nsIContent* aNode,
                          int32_t aStartOffset,
                          int32_t aEndOffset,
                          nsAString& aStr,
                          bool aTranslateEntities);

  virtual nsresult PushNameSpaceDecl(const nsAString& aPrefix,
                                     const nsAString& aURI,
                                     nsIContent* aOwner);
  void PopNameSpaceDeclsFor(nsIContent* aOwner);

  /**
   * The problem that ConfirmPrefix fixes is that anyone can insert nodes
   * through the DOM that have a namespace URI and a random or empty or
   * previously existing prefix that's totally unrelated to the prefixes
   * declared at that point through xmlns attributes.  So what ConfirmPrefix
   * does is ensure that we can map aPrefix to the namespace URI aURI (for
   * example, that the prefix is not already mapped to some other namespace).
   * aPrefix will be adjusted, if necessary, so the value of the prefix
   * _after_ this call is what should be serialized.
   * @param aPrefix the prefix that may need adjusting
   * @param aURI the namespace URI we want aPrefix to point to
   * @param aElement the element we're working with (needed for proper default
   *                 namespace handling)
   * @param aIsAttribute true if we're confirming a prefix for an attribute.
   * @return true if we need to push the (prefix, uri) pair on the namespace
   *                 stack (note that this can happen even if the prefix is
   *                 empty).
   */
  bool ConfirmPrefix(nsAString& aPrefix,
                       const nsAString& aURI,
                       nsIContent* aElement,
                       bool aIsAttribute);
  /**
   * GenerateNewPrefix generates a new prefix and writes it to aPrefix
   */
  void GenerateNewPrefix(nsAString& aPrefix);

  uint32_t ScanNamespaceDeclarations(nsIContent* aContent,
                                     nsIContent *aOriginalElement,
                                     const nsAString& aTagNamespaceURI);

  MOZ_MUST_USE
  virtual bool SerializeAttributes(nsIContent* aContent,
                                   nsIContent *aOriginalElement,
                                   nsAString& aTagPrefix,
                                   const nsAString& aTagNamespaceURI,
                                   nsIAtom* aTagName,
                                   nsAString& aStr,
                                   uint32_t aSkipAttr,
                                   bool aAddNSAttr);

  MOZ_MUST_USE
  bool SerializeAttr(const nsAString& aPrefix,
                     const nsAString& aName,
                     const nsAString& aValue,
                     nsAString& aStr,
                     bool aDoEscapeEntities);

  bool IsJavaScript(nsIContent * aContent,
                      nsIAtom* aAttrNameAtom,
                      int32_t aAttrNamespaceID,
                      const nsAString& aValueString);

  /**
   * This method can be redefined to check if the element can be serialized.
   * It is called when the serialization of the start tag is asked 
   * (AppendElementStart)
   * In this method you can also force the formating
   * by setting aForceFormat to true.
   * @return boolean  true if the element can be output
   */
  virtual bool CheckElementStart(nsIContent * aContent,
                                   bool & aForceFormat,
                                   nsAString& aStr,
                                   nsresult& aResult);

  /**
   * This method is responsible for appending the '>' at the end of the start
   * tag, possibly preceded by '/' and maybe a ' ' before that too.
   *
   * aElement and aOriginalElement are the same as the corresponding arguments
   * to AppendElementStart.
   */
  MOZ_MUST_USE
  bool AppendEndOfElementStart(mozilla::dom::Element* aEleemnt,
                               mozilla::dom::Element* aOriginalElement,
                               nsAString& aStr);

  /**
   * This method can be redefine to serialize additional things just after
   * after the serialization ot the start tag.
   * (called at the end of AppendElementStart)
   */
  MOZ_MUST_USE
  virtual bool AfterElementStart(nsIContent* aContent,
                                 nsIContent* aOriginalElement,
                                 nsAString& aStr) { return true; };

  /**
   * This method can be redefined to check if the element can be serialized.
   * It is called when the serialization of the end tag is asked 
   * (AppendElementEnd)
   * In this method you can also force the formating
   * by setting aForceFormat to true.
   * @return boolean  true if the element can be output
   */
  virtual bool CheckElementEnd(mozilla::dom::Element* aElement,
                               bool& aForceFormat,
                               nsAString& aStr);

  /**
   * This method can be redefine to serialize additional things just after
   * after the serialization ot the end tag.
   * (called at the end of AppendElementStart)
   */
  virtual void AfterElementEnd(nsIContent * aContent,
                               nsAString& aStr) { };

  /**
   * Returns true if a line break should be inserted before an element open tag
   */
  virtual bool LineBreakBeforeOpen(int32_t aNamespaceID, nsIAtom* aName);

  /**
   * Returns true if a line break should be inserted after an element open tag
   */
  virtual bool LineBreakAfterOpen(int32_t aNamespaceID, nsIAtom* aName);

  /**
   * Returns true if a line break should be inserted after an element close tag
   */
  virtual bool LineBreakBeforeClose(int32_t aNamespaceID, nsIAtom* aName);

  /**
   * Returns true if a line break should be inserted after an element close tag
   */
  virtual bool LineBreakAfterClose(int32_t aNamespaceID, nsIAtom* aName);

  /**
   * add intendation. Call only in the case of formating and if the current
   * position is at 0. It updates the column position.
   */
  MOZ_MUST_USE
  bool AppendIndentation(nsAString& aStr);

  MOZ_MUST_USE
  bool IncrIndentation(nsIAtom* aName);
  void DecrIndentation(nsIAtom* aName);

  // Functions to check for newlines that needs to be added between nodes in
  // the root of a document. See mAddNewlineForRootNode
  MOZ_MUST_USE
  bool MaybeAddNewlineForRootNode(nsAString& aStr);
  void MaybeFlagNewlineForRootNode(nsINode* aNode);

  // Functions to check if we enter in or leave from a preformated content
  virtual void MaybeEnterInPreContent(nsIContent* aNode);
  virtual void MaybeLeaveFromPreContent(nsIContent* aNode);

  bool ShouldMaintainPreLevel() const;
  int32_t PreLevel() const {
    MOZ_ASSERT(ShouldMaintainPreLevel());
    return mPreLevel;
  }
  int32_t& PreLevel() {
    MOZ_ASSERT(ShouldMaintainPreLevel());
    return mPreLevel;
  }

  int32_t mPrefixIndex;

  struct NameSpaceDecl {
    nsString mPrefix;
    nsString mURI;
    nsIContent* mOwner;
  };

  nsTArray<NameSpaceDecl> mNameSpaceStack;

  // nsIDocumentEncoder flags
  uint32_t  mFlags;

  // characters to use for line break
  nsString  mLineBreak;

  // The charset that was passed to Init()
  nsCString mCharset;
  
  // current column position on the current line
  uint32_t   mColPos;

  // true = pretty formating should be done (OutputFormated flag)
  bool mDoFormat;

  // true = no formatting,(OutputRaw flag)
  // no newline convertion and no rewrap long lines even if OutputWrap is set.
  bool mDoRaw;

  // true = wrapping should be done (OutputWrap flag)
  bool mDoWrap;

  // true = we can break lines (OutputDisallowLineBreaking flag)
  bool mAllowLineBreaking;

  // number of maximum column in a line, in the wrap mode
  uint32_t   mMaxColumn;

  // current indent value
  nsString   mIndent;

  // this is the indentation level after the indentation reached
  // the maximum length of indentation
  int32_t    mIndentOverflow;

  // says if the indentation has been already added on the current line
  bool mIsIndentationAddedOnCurrentLine;

  // the string which is currently added is in an attribute
  bool mInAttribute;

  // true = a newline character should be added. It's only
  // useful when serializing root nodes. see MaybeAddNewlineForRootNode and
  // MaybeFlagNewlineForRootNode
  bool mAddNewlineForRootNode;

  // Indicates that a space will be added if and only if content is
  // continued on the same line while serializing source.  Otherwise,
  // the newline character acts as the whitespace and no space is needed.
  // used when mDoFormat = true
  bool          mAddSpace;

  // says that if the next string to add contains a newline character at the
  // begining, then this newline character should be ignored, because a
  // such character has already been added into the output string
  bool          mMayIgnoreLineBreakSequence;

  bool          mBodyOnly;
  int32_t       mInBody;

private:
  // number of nested elements which have preformated content
  int32_t       mPreLevel;
};

nsresult
NS_NewXMLContentSerializer(nsIContentSerializer** aSerializer);

#endif