The Tor Browser / file revision

 /* -*- Mode: C++; tab-width: 2; 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/. */

 /*

  * nsIContentSerializer implementation that can be used with an

  * nsIDocumentEncoder to convert a DOM into plaintext in a nice way

  * (eg for copy/paste as plaintext).

  */

 #include "nsPlainTextSerializer.h"

 #include "nsLWBrkCIID.h"

 #include "nsIServiceManager.h"

 #include "nsGkAtoms.h"

 #include "nsNameSpaceManager.h"

 #include "nsTextFragment.h"

 #include "nsContentUtils.h"

 #include "nsReadableUtils.h"

 #include "nsUnicharUtils.h"

 #include "nsCRT.h"

 #include "mozilla/dom/Element.h"

 #include "mozilla/Preferences.h"

 using namespace mozilla;

 using namespace mozilla::dom;

 #define PREF_STRUCTS "converter.html2txt.structs"

 #define PREF_HEADER_STRATEGY "converter.html2txt.header_strategy"

 static const  int32_t kTabSize=4;

 static const  int32_t kIndentSizeHeaders = 2;  /* Indention of h1, if

                                                 mHeaderStrategy = 1 or = 2.

                                                 Indention of other headers

                                                 is derived from that.

                                                 XXX center h1? */

 static const  int32_t kIndentIncrementHeaders = 2;  /* If mHeaderStrategy = 1,

                                                 indent h(x+1) this many

                                                 columns more than h(x) */

 static const  int32_t kIndentSizeList = kTabSize;

                                // Indention of non-first lines of ul and ol

 static const  int32_t kIndentSizeDD = kTabSize;  // Indention of <dd>

 static const  char16_t  kNBSP = 160;

 static const  char16_t kSPACE = ' ';

 static int32_t HeaderLevel(nsIAtom* aTag);

 static int32_t GetUnicharWidth(char16_t ucs);

 static int32_t GetUnicharStringWidth(const char16_t* pwcs, int32_t n);

 // Someday may want to make this non-const:

 static const uint32_t TagStackSize = 500;

 static const uint32_t OLStackSize = 100;

 nsresult NS_NewPlainTextSerializer(nsIContentSerializer** aSerializer)

 {

   nsPlainTextSerializer* it = new nsPlainTextSerializer();

   if (!it) {

     return NS_ERROR_OUT_OF_MEMORY;

   }

   return CallQueryInterface(it, aSerializer);

 }

 nsPlainTextSerializer::nsPlainTextSerializer()

   : kSpace(NS_LITERAL_STRING(" ")) // Init of "constant"

 {

   mOutputString = nullptr;

   mHeadLevel = 0;

   mAtFirstColumn = true;

   mIndent = 0;

   mCiteQuoteLevel = 0;

   mStructs = true;       // will be read from prefs later

   mHeaderStrategy = 1 /*indent increasingly*/;   // ditto

   mDontWrapAnyQuotes = false;                 // ditto

   mHasWrittenCiteBlockquote = false;

   mSpanLevel = 0;

   for (int32_t i = 0; i <= 6; i++) {

     mHeaderCounter[i] = 0;

   }

   // Line breaker

   mWrapColumn = 72;     // XXX magic number, we expect someone to reset this

   mCurrentLineWidth = 0;

   // Flow

   mEmptyLines = 1; // The start of the document is an "empty line" in itself,

   mInWhitespace = false;

   mPreFormatted = false;

   mStartedOutput = false;

   // initialize the tag stack to zero:

   // The stack only ever contains pointers to static atoms, so they don't

   // need refcounting.

   mTagStack = new nsIAtom*[TagStackSize];

   mTagStackIndex = 0;

   mIgnoreAboveIndex = (uint32_t)kNotFound;

   // initialize the OL stack, where numbers for ordered lists are kept

   mOLStack = new int32_t[OLStackSize];

   mOLStackIndex = 0;

   mULCount = 0;

   mIgnoredChildNodeLevel = 0;

 }

 nsPlainTextSerializer::~nsPlainTextSerializer()

 {

   delete[] mTagStack;

   delete[] mOLStack;

   NS_WARN_IF_FALSE(mHeadLevel == 0, "Wrong head level!");

 }

 NS_IMPL_ISUPPORTS(nsPlainTextSerializer,

                   nsIContentSerializer)

 NS_IMETHODIMP 

 nsPlainTextSerializer::Init(uint32_t aFlags, uint32_t aWrapColumn,

                             const char* aCharSet, bool aIsCopying,

                             bool aIsWholeDocument)

 {

 #ifdef DEBUG

   // Check if the major control flags are set correctly.

   if (aFlags & nsIDocumentEncoder::OutputFormatFlowed) {

     NS_ASSERTION(aFlags & nsIDocumentEncoder::OutputFormatted,

                  "If you want format=flowed, you must combine it with "

                  "nsIDocumentEncoder::OutputFormatted");

   }

   if (aFlags & nsIDocumentEncoder::OutputFormatted) {

     NS_ASSERTION(!(aFlags & nsIDocumentEncoder::OutputPreformatted),

                  "Can't do formatted and preformatted output at the same time!");

   }

 #endif

   mFlags = aFlags;

   mWrapColumn = aWrapColumn;

   // Only create a linebreaker if we will handle wrapping.

   if (MayWrap()) {

     mLineBreaker = nsContentUtils::LineBreaker();

   }

   // Set the line break character:

   if ((mFlags & nsIDocumentEncoder::OutputCRLineBreak)

       && (mFlags & nsIDocumentEncoder::OutputLFLineBreak)) {

     // Windows

     mLineBreak.AssignLiteral("\r\n");

   }

   else if (mFlags & nsIDocumentEncoder::OutputCRLineBreak) {

     // Mac

     mLineBreak.Assign(char16_t('\r'));

   }

   else if (mFlags & nsIDocumentEncoder::OutputLFLineBreak) {

     // Unix/DOM

     mLineBreak.Assign(char16_t('\n'));

   }

   else {

     // Platform/default

     mLineBreak.AssignLiteral(NS_LINEBREAK);

   }

   mLineBreakDue = false;

   mFloatingLines = -1;

   if (mFlags & nsIDocumentEncoder::OutputFormatted) {

     // Get some prefs that controls how we do formatted output

     mStructs = Preferences::GetBool(PREF_STRUCTS, mStructs);

     mHeaderStrategy =

       Preferences::GetInt(PREF_HEADER_STRATEGY, mHeaderStrategy);

     // DontWrapAnyQuotes is set according to whether plaintext mail

     // is wrapping to window width -- see bug 134439.

     // We'll only want this if we're wrapping and formatted.

     if (mFlags & nsIDocumentEncoder::OutputWrap || mWrapColumn > 0) {

       mDontWrapAnyQuotes =

         Preferences::GetBool("mail.compose.wrap_to_window_width",

                              mDontWrapAnyQuotes);

     }

   }

   // XXX We should let the caller pass this in.

   if (Preferences::GetBool("browser.frames.enabled")) {

     mFlags &= ~nsIDocumentEncoder::OutputNoFramesContent;

   }

   else {

     mFlags |= nsIDocumentEncoder::OutputNoFramesContent;

   }

   return NS_OK;

 }

 bool

 nsPlainTextSerializer::GetLastBool(const nsTArray<bool>& aStack)

 {

   uint32_t size = aStack.Length();

   if (size == 0) {

     return false;

   }

   return aStack.ElementAt(size-1);

 }

 void

 nsPlainTextSerializer::SetLastBool(nsTArray<bool>& aStack, bool aValue)

 {

   uint32_t size = aStack.Length();

   if (size > 0) {

     aStack.ElementAt(size-1) = aValue;

   }

   else {

     NS_ERROR("There is no \"Last\" value");

   }

 }

 void

 nsPlainTextSerializer::PushBool(nsTArray<bool>& aStack, bool aValue)

 {

     aStack.AppendElement(bool(aValue));

 }

 bool

 nsPlainTextSerializer::PopBool(nsTArray<bool>& aStack)

 {

   bool returnValue = false;

   uint32_t size = aStack.Length();

   if (size > 0) {

     returnValue = aStack.ElementAt(size-1);

     aStack.RemoveElementAt(size-1);

   }

   return returnValue;

 }

 bool

 nsPlainTextSerializer::ShouldReplaceContainerWithPlaceholder(nsIAtom* aTag)

 {

   // If nsIDocumentEncoder::OutputNonTextContentAsPlaceholder is set,

   // non-textual container element should be serialized as placeholder

   // character and its child nodes should be ignored. See bug 895239.

   if (!(mFlags & nsIDocumentEncoder::OutputNonTextContentAsPlaceholder)) {

     return false;

   }

   return

     (aTag == nsGkAtoms::audio) ||

     (aTag == nsGkAtoms::canvas) ||

     (aTag == nsGkAtoms::iframe) ||

     (aTag == nsGkAtoms::meter) ||

     (aTag == nsGkAtoms::progress) ||

     (aTag == nsGkAtoms::object) ||

     (aTag == nsGkAtoms::svg) ||

     (aTag == nsGkAtoms::video);

 }

 NS_IMETHODIMP 

 nsPlainTextSerializer::AppendText(nsIContent* aText,

                                   int32_t aStartOffset,

                                   int32_t aEndOffset, 

                                   nsAString& aStr)

 {

   if (mIgnoreAboveIndex != (uint32_t)kNotFound) {

     return NS_OK;

   }

   NS_ASSERTION(aStartOffset >= 0, "Negative start offset for text fragment!");

   if ( aStartOffset < 0 )

     return NS_ERROR_INVALID_ARG;

   NS_ENSURE_ARG(aText);

   nsresult rv = NS_OK;

   nsIContent* content = aText;

   const nsTextFragment* frag;

   if (!content || !(frag = content->GetText())) {

     return NS_ERROR_FAILURE;

   }

   int32_t fragLength = frag->GetLength();

   int32_t endoffset = (aEndOffset == -1) ? fragLength : std::min(aEndOffset, fragLength);

   NS_ASSERTION(aStartOffset <= endoffset, "A start offset is beyond the end of the text fragment!");

   int32_t length = endoffset - aStartOffset;

   if (length <= 0) {

     return NS_OK;

   }

   nsAutoString textstr;

   if (frag->Is2b()) {

     textstr.Assign(frag->Get2b() + aStartOffset, length);

   }

   else {

     // AssignASCII is for 7-bit character only, so don't use it

     const char *data = frag->Get1b();

     CopyASCIItoUTF16(Substring(data + aStartOffset, data + endoffset), textstr);

   }

   mOutputString = &aStr;

   // We have to split the string across newlines

   // to match parser behavior

   int32_t start = 0;

   int32_t offset = textstr.FindCharInSet("\n\r");

   while (offset != kNotFound) {

     if (offset>start) {

       // Pass in the line

       DoAddText(false,

                 Substring(textstr, start, offset-start));

     }

     // Pass in a newline

     DoAddText(true, mLineBreak);

     start = offset+1;

     offset = textstr.FindCharInSet("\n\r", start);

   }

   // Consume the last bit of the string if there's any left

   if (start < length) {

     if (start) {

       DoAddText(false, Substring(textstr, start, length - start));

     }

     else {

       DoAddText(false, textstr);

     }

   }

   mOutputString = nullptr;

   return rv;

 }

 NS_IMETHODIMP

 nsPlainTextSerializer::AppendCDATASection(nsIContent* aCDATASection,

                                           int32_t aStartOffset,

                                           int32_t aEndOffset,

                                           nsAString& aStr)

 {

   return AppendText(aCDATASection, aStartOffset, aEndOffset, aStr);

 }

 NS_IMETHODIMP

 nsPlainTextSerializer::AppendElementStart(Element* aElement,

                                           Element* aOriginalElement,

                                           nsAString& aStr)

 {

   NS_ENSURE_ARG(aElement);

   mElement = aElement;

   nsresult rv;

   nsIAtom* id = GetIdForContent(mElement);

   bool isContainer = !nsContentUtils::IsHTMLVoid(id);

   mOutputString = &aStr;

   if (isContainer) {

     rv = DoOpenContainer(id);

   }

   else {

     rv = DoAddLeaf(id);

   }

   mElement = nullptr;

   mOutputString = nullptr;

   if (id == nsGkAtoms::head) {

     ++mHeadLevel;

   }

   return rv;

 } 

 NS_IMETHODIMP 

 nsPlainTextSerializer::AppendElementEnd(Element* aElement,

                                         nsAString& aStr)

 {

   NS_ENSURE_ARG(aElement);

   mElement = aElement;

   nsresult rv;

   nsIAtom* id = GetIdForContent(mElement);

   bool isContainer = !nsContentUtils::IsHTMLVoid(id);

   mOutputString = &aStr;

   rv = NS_OK;

   if (isContainer) {

     rv = DoCloseContainer(id);

   }

   mElement = nullptr;

   mOutputString = nullptr;

   if (id == nsGkAtoms::head) {

     NS_ASSERTION(mHeadLevel != 0,

                  "mHeadLevel being decremented below 0");

     --mHeadLevel;

   }

   return rv;

 }

 NS_IMETHODIMP 

 nsPlainTextSerializer::Flush(nsAString& aStr)

 {

   mOutputString = &aStr;

   FlushLine();

   mOutputString = nullptr;

   return NS_OK;

 }

 NS_IMETHODIMP

 nsPlainTextSerializer::AppendDocumentStart(nsIDocument *aDocument,

                                            nsAString& aStr)

 {

   return NS_OK;

 }

 nsresult

 nsPlainTextSerializer::DoOpenContainer(nsIAtom* aTag)

 {

   // Check if we need output current node as placeholder character and ignore

   // child nodes.

   if (ShouldReplaceContainerWithPlaceholder(mElement->Tag())) {

     if (mIgnoredChildNodeLevel == 0) {

       // Serialize current node as placeholder character

       Write(NS_LITERAL_STRING("\xFFFC"));

     }

     // Ignore child nodes.

     mIgnoredChildNodeLevel++;

     return NS_OK;

   }

   if (mFlags & nsIDocumentEncoder::OutputRaw) {

     // Raw means raw.  Don't even think about doing anything fancy

     // here like indenting, adding line breaks or any other

     // characters such as list item bullets, quote characters

     // around <q>, etc.  I mean it!  Don't make me smack you!

     return NS_OK;

   }

   if (mTagStackIndex < TagStackSize) {

     mTagStack[mTagStackIndex++] = aTag;

   }

   if (mIgnoreAboveIndex != (uint32_t)kNotFound) {

     return NS_OK;

   }

   // Reset this so that <blockquote type=cite> doesn't affect the whitespace

   // above random <pre>s below it.

   mHasWrittenCiteBlockquote = mHasWrittenCiteBlockquote &&

                               aTag == nsGkAtoms::pre;

   bool isInCiteBlockquote = false;

   // XXX special-case <blockquote type=cite> so that we don't add additional

   // newlines before the text.

   if (aTag == nsGkAtoms::blockquote) {

     nsAutoString value;

     nsresult rv = GetAttributeValue(nsGkAtoms::type, value);

     isInCiteBlockquote = NS_SUCCEEDED(rv) && value.EqualsIgnoreCase("cite");

   }

   if (mLineBreakDue && !isInCiteBlockquote)

     EnsureVerticalSpace(mFloatingLines);

   // Check if this tag's content that should not be output

   if ((aTag == nsGkAtoms::noscript &&

        !(mFlags & nsIDocumentEncoder::OutputNoScriptContent)) ||

       ((aTag == nsGkAtoms::iframe || aTag == nsGkAtoms::noframes) &&

        !(mFlags & nsIDocumentEncoder::OutputNoFramesContent))) {

     // Ignore everything that follows the current tag in 

     // question until a matching end tag is encountered.

     mIgnoreAboveIndex = mTagStackIndex - 1;

     return NS_OK;

   }

   if (aTag == nsGkAtoms::body) {

     // Try to figure out here whether we have a

     // preformatted style attribute.

     //

     // Trigger on the presence of a "pre-wrap" in the

     // style attribute. That's a very simplistic way to do

     // it, but better than nothing.

     // Also set mWrapColumn to the value given there

     // (which arguably we should only do if told to do so).

     nsAutoString style;

     int32_t whitespace;

     if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::style, style)) &&

        (kNotFound != (whitespace = style.Find("white-space:")))) {

       if (kNotFound != style.Find("pre-wrap", true, whitespace)) {

 #ifdef DEBUG_preformatted

         printf("Set mPreFormatted based on style pre-wrap\n");

 #endif

         mPreFormatted = true;

         int32_t widthOffset = style.Find("width:");

         if (widthOffset >= 0) {

           // We have to search for the ch before the semicolon,

           // not for the semicolon itself, because nsString::ToInteger()

           // considers 'c' to be a valid numeric char (even if radix=10)

           // but then gets confused if it sees it next to the number

           // when the radix specified was 10, and returns an error code.

           int32_t semiOffset = style.Find("ch", false, widthOffset+6);

           int32_t length = (semiOffset > 0 ? semiOffset - widthOffset - 6

                             : style.Length() - widthOffset);

           nsAutoString widthstr;

           style.Mid(widthstr, widthOffset+6, length);

           nsresult err;

           int32_t col = widthstr.ToInteger(&err);

           if (NS_SUCCEEDED(err)) {

             mWrapColumn = (uint32_t)col;

 #ifdef DEBUG_preformatted

             printf("Set wrap column to %d based on style\n", mWrapColumn);

 #endif

           }

         }

       }

       else if (kNotFound != style.Find("pre", true, whitespace)) {

 #ifdef DEBUG_preformatted

         printf("Set mPreFormatted based on style pre\n");

 #endif

         mPreFormatted = true;

         mWrapColumn = 0;

       }

     } 

     else {

       /* See comment at end of function. */

       mInWhitespace = true;

       mPreFormatted = false;

     }

     return NS_OK;

   }

   // Keep this in sync with DoCloseContainer!

   if (!DoOutput()) {

     return NS_OK;

   }

   if (aTag == nsGkAtoms::p)

     EnsureVerticalSpace(1);

   else if (aTag == nsGkAtoms::pre) {

     if (GetLastBool(mIsInCiteBlockquote))

       EnsureVerticalSpace(0);

     else if (mHasWrittenCiteBlockquote) {

       EnsureVerticalSpace(0);

       mHasWrittenCiteBlockquote = false;

     }

     else

       EnsureVerticalSpace(1);

   }

   else if (aTag == nsGkAtoms::tr) {

     PushBool(mHasWrittenCellsForRow, false);

   }

   else if (aTag == nsGkAtoms::td || aTag == nsGkAtoms::th) {

     // We must make sure that the content of two table cells get a

     // space between them.

     // To make the separation between cells most obvious and

     // importable, we use a TAB.

     if (GetLastBool(mHasWrittenCellsForRow)) {

       // Bypass |Write| so that the TAB isn't compressed away.

       AddToLine(MOZ_UTF16("\t"), 1);

       mInWhitespace = true;

     }

     else if (mHasWrittenCellsForRow.IsEmpty()) {

       // We don't always see a <tr> (nor a <table>) before the <td> if we're

       // copying part of a table

       PushBool(mHasWrittenCellsForRow, true); // will never be popped

     }

     else {

       SetLastBool(mHasWrittenCellsForRow, true);

     }

   }

   else if (aTag == nsGkAtoms::ul) {

     // Indent here to support nested lists, which aren't included in li :-(

     EnsureVerticalSpace(mULCount + mOLStackIndex == 0 ? 1 : 0);

          // Must end the current line before we change indention

     mIndent += kIndentSizeList;

     mULCount++;

   }

   else if (aTag == nsGkAtoms::ol) {

     EnsureVerticalSpace(mULCount + mOLStackIndex == 0 ? 1 : 0);

     if (mFlags & nsIDocumentEncoder::OutputFormatted) {

       // Must end the current line before we change indention

       if (mOLStackIndex < OLStackSize) {

         nsAutoString startAttr;

         int32_t startVal = 1;

         if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::start, startAttr))) {

           nsresult rv = NS_OK;

           startVal = startAttr.ToInteger(&rv);

           if (NS_FAILED(rv))

             startVal = 1;

         }

         mOLStack[mOLStackIndex++] = startVal;

       }

     } else {

       mOLStackIndex++;

     }

     mIndent += kIndentSizeList;  // see ul

   }

   else if (aTag == nsGkAtoms::li &&

            (mFlags & nsIDocumentEncoder::OutputFormatted)) {

     if (mTagStackIndex > 1 && IsInOL()) {

       if (mOLStackIndex > 0) {

         nsAutoString valueAttr;

         if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::value, valueAttr))) {

           nsresult rv = NS_OK;

           int32_t valueAttrVal = valueAttr.ToInteger(&rv);

           if (NS_SUCCEEDED(rv))

             mOLStack[mOLStackIndex-1] = valueAttrVal;

         }

         // This is what nsBulletFrame does for OLs:

         mInIndentString.AppendInt(mOLStack[mOLStackIndex-1]++, 10);

       }

       else {

         mInIndentString.Append(char16_t('#'));

       }

       mInIndentString.Append(char16_t('.'));

     }

     else {

       static char bulletCharArray[] = "*o+#";

       uint32_t index = mULCount > 0 ? (mULCount - 1) : 3;

       char bulletChar = bulletCharArray[index % 4];

       mInIndentString.Append(char16_t(bulletChar));

     }

     mInIndentString.Append(char16_t(' '));

   }

   else if (aTag == nsGkAtoms::dl) {

     EnsureVerticalSpace(1);

   }

   else if (aTag == nsGkAtoms::dt) {

     EnsureVerticalSpace(0);

   }

   else if (aTag == nsGkAtoms::dd) {

     EnsureVerticalSpace(0);

     mIndent += kIndentSizeDD;

   }

   else if (aTag == nsGkAtoms::span) {

     ++mSpanLevel;

   }

   else if (aTag == nsGkAtoms::blockquote) {

     // Push

     PushBool(mIsInCiteBlockquote, isInCiteBlockquote);

     if (isInCiteBlockquote) {

       EnsureVerticalSpace(0);

       mCiteQuoteLevel++;

     }

     else {

       EnsureVerticalSpace(1);

       mIndent += kTabSize; // Check for some maximum value?

     }

   }

   else if (aTag == nsGkAtoms::q) {

     Write(NS_LITERAL_STRING("\""));

   }

   // Else make sure we'll separate block level tags,

   // even if we're about to leave, before doing any other formatting.

   else if (nsContentUtils::IsHTMLBlock(aTag)) {

     EnsureVerticalSpace(0);

   }

   //////////////////////////////////////////////////////////////

   if (!(mFlags & nsIDocumentEncoder::OutputFormatted)) {

     return NS_OK;

   }

   //////////////////////////////////////////////////////////////

   // The rest of this routine is formatted output stuff,

   // which we should skip if we're not formatted:

   //////////////////////////////////////////////////////////////

   // Push on stack

   bool currentNodeIsConverted = IsCurrentNodeConverted();

   if (aTag == nsGkAtoms::h1 || aTag == nsGkAtoms::h2 ||

       aTag == nsGkAtoms::h3 || aTag == nsGkAtoms::h4 ||

       aTag == nsGkAtoms::h5 || aTag == nsGkAtoms::h6)

   {

     EnsureVerticalSpace(2);

     if (mHeaderStrategy == 2) {  // numbered

       mIndent += kIndentSizeHeaders;

       // Caching

       int32_t level = HeaderLevel(aTag);

       // Increase counter for current level

       mHeaderCounter[level]++;

       // Reset all lower levels

       int32_t i;

       for (i = level + 1; i <= 6; i++) {

         mHeaderCounter[i] = 0;

       }

       // Construct numbers

       nsAutoString leadup;

       for (i = 1; i <= level; i++) {

         leadup.AppendInt(mHeaderCounter[i]);

         leadup.Append(char16_t('.'));

       }

       leadup.Append(char16_t(' '));

       Write(leadup);

     }

     else if (mHeaderStrategy == 1) { // indent increasingly

       mIndent += kIndentSizeHeaders;

       for (int32_t i = HeaderLevel(aTag); i > 1; i--) {

            // for h(x), run x-1 times

         mIndent += kIndentIncrementHeaders;

       }

     }

   }

   else if (aTag == nsGkAtoms::a && !currentNodeIsConverted) {

     nsAutoString url;

     if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::href, url))

         && !url.IsEmpty()) {

       mURL = url;

     }

   }

   else if (aTag == nsGkAtoms::sup && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("^"));

   }

   else if (aTag == nsGkAtoms::sub && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("_"));

   }

   else if (aTag == nsGkAtoms::code && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("|"));

   }

   else if ((aTag == nsGkAtoms::strong || aTag == nsGkAtoms::b)

            && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("*"));

   }

   else if ((aTag == nsGkAtoms::em || aTag == nsGkAtoms::i)

            && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("/"));

   }

   else if (aTag == nsGkAtoms::u && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("_"));

   }

   /* Container elements are always block elements, so we shouldn't

      output any whitespace immediately after the container tag even if

      there's extra whitespace there because the HTML is pretty-printed

      or something. To ensure that happens, tell the serializer we're

      already in whitespace so it won't output more. */

   mInWhitespace = true;

   return NS_OK;

 }

 nsresult

 nsPlainTextSerializer::DoCloseContainer(nsIAtom* aTag)

 {

   if (ShouldReplaceContainerWithPlaceholder(mElement->Tag())) {

     mIgnoredChildNodeLevel--;

     return NS_OK;

   }

   if (mFlags & nsIDocumentEncoder::OutputRaw) {

     // Raw means raw.  Don't even think about doing anything fancy

     // here like indenting, adding line breaks or any other

     // characters such as list item bullets, quote characters

     // around <q>, etc.  I mean it!  Don't make me smack you!

     return NS_OK;

   }

   if (mTagStackIndex > 0) {

     --mTagStackIndex;

   }

   if (mTagStackIndex >= mIgnoreAboveIndex) {

     if (mTagStackIndex == mIgnoreAboveIndex) {

       // We're dealing with the close tag whose matching

       // open tag had set the mIgnoreAboveIndex value.

       // Reset mIgnoreAboveIndex before discarding this tag.

       mIgnoreAboveIndex = (uint32_t)kNotFound;

     }

     return NS_OK;

   }

   // End current line if we're ending a block level tag

   if ((aTag == nsGkAtoms::body) || (aTag == nsGkAtoms::html)) {

     // We want the output to end with a new line,

     // but in preformatted areas like text fields,

     // we can't emit newlines that weren't there.

     // So add the newline only in the case of formatted output.

     if (mFlags & nsIDocumentEncoder::OutputFormatted) {

       EnsureVerticalSpace(0);

     }

     else {

       FlushLine();

     }

     // We won't want to do anything with these in formatted mode either,

     // so just return now:

     return NS_OK;

   }

   // Keep this in sync with DoOpenContainer!

   if (!DoOutput()) {

     return NS_OK;

   }

   if (aTag == nsGkAtoms::tr) {

     PopBool(mHasWrittenCellsForRow);

     // Should always end a line, but get no more whitespace

     if (mFloatingLines < 0)

       mFloatingLines = 0;

     mLineBreakDue = true;

   }

   else if (((aTag == nsGkAtoms::li) ||

             (aTag == nsGkAtoms::dt)) &&

            (mFlags & nsIDocumentEncoder::OutputFormatted)) {

     // Items that should always end a line, but get no more whitespace

     if (mFloatingLines < 0)

       mFloatingLines = 0;

     mLineBreakDue = true;

   }

   else if (aTag == nsGkAtoms::pre) {

     mFloatingLines = GetLastBool(mIsInCiteBlockquote) ? 0 : 1;

     mLineBreakDue = true;

   }

   else if (aTag == nsGkAtoms::ul) {

     FlushLine();

     mIndent -= kIndentSizeList;

     if (--mULCount + mOLStackIndex == 0) {

       mFloatingLines = 1;

       mLineBreakDue = true;

     }

   }

   else if (aTag == nsGkAtoms::ol) {

     FlushLine(); // Doing this after decreasing OLStackIndex would be wrong.

     mIndent -= kIndentSizeList;

     NS_ASSERTION(mOLStackIndex, "Wrong OLStack level!");

     mOLStackIndex--;

     if (mULCount + mOLStackIndex == 0) {

       mFloatingLines = 1;

       mLineBreakDue = true;

     }

   }  

   else if (aTag == nsGkAtoms::dl) {

     mFloatingLines = 1;

     mLineBreakDue = true;

   }

   else if (aTag == nsGkAtoms::dd) {

     FlushLine();

     mIndent -= kIndentSizeDD;

   }

   else if (aTag == nsGkAtoms::span) {

     NS_ASSERTION(mSpanLevel, "Span level will be negative!");

     --mSpanLevel;

   }

   else if (aTag == nsGkAtoms::div) {

     if (mFloatingLines < 0)

       mFloatingLines = 0;

     mLineBreakDue = true;

   }

   else if (aTag == nsGkAtoms::blockquote) {

     FlushLine();    // Is this needed?

     // Pop

     bool isInCiteBlockquote = PopBool(mIsInCiteBlockquote);

     if (isInCiteBlockquote) {

       NS_ASSERTION(mCiteQuoteLevel, "CiteQuote level will be negative!");

       mCiteQuoteLevel--;

       mFloatingLines = 0;

       mHasWrittenCiteBlockquote = true;

     }

     else {

       mIndent -= kTabSize;

       mFloatingLines = 1;

     }

     mLineBreakDue = true;

   }

   else if (aTag == nsGkAtoms::q) {

     Write(NS_LITERAL_STRING("\""));

   }

   else if (nsContentUtils::IsHTMLBlock(aTag)

            && aTag != nsGkAtoms::script) {

     // All other blocks get 1 vertical space after them

     // in formatted mode, otherwise 0.

     // This is hard. Sometimes 0 is a better number, but

     // how to know?

     if (mFlags & nsIDocumentEncoder::OutputFormatted)

       EnsureVerticalSpace(1);

     else {

       if (mFloatingLines < 0)

         mFloatingLines = 0;

       mLineBreakDue = true;

     }

   }

   //////////////////////////////////////////////////////////////

   if (!(mFlags & nsIDocumentEncoder::OutputFormatted)) {

     return NS_OK;

   }

   //////////////////////////////////////////////////////////////

   // The rest of this routine is formatted output stuff,

   // which we should skip if we're not formatted:

   //////////////////////////////////////////////////////////////

   // Pop the currentConverted stack

   bool currentNodeIsConverted = IsCurrentNodeConverted();

   if (aTag == nsGkAtoms::h1 || aTag == nsGkAtoms::h2 ||

       aTag == nsGkAtoms::h3 || aTag == nsGkAtoms::h4 ||

       aTag == nsGkAtoms::h5 || aTag == nsGkAtoms::h6) {

     if (mHeaderStrategy) {  /*numbered or indent increasingly*/ 

       mIndent -= kIndentSizeHeaders;

     }

     if (mHeaderStrategy == 1 /*indent increasingly*/ ) {

       for (int32_t i = HeaderLevel(aTag); i > 1; i--) {

            // for h(x), run x-1 times

         mIndent -= kIndentIncrementHeaders;

       }

     }

     EnsureVerticalSpace(1);

   }

   else if (aTag == nsGkAtoms::a && !currentNodeIsConverted && !mURL.IsEmpty()) {

     nsAutoString temp; 

     temp.AssignLiteral(" <");

     temp += mURL;

     temp.Append(char16_t('>'));

     Write(temp);

     mURL.Truncate();

   }

   else if ((aTag == nsGkAtoms::sup || aTag == nsGkAtoms::sub)

            && mStructs && !currentNodeIsConverted) {

     Write(kSpace);

   }

   else if (aTag == nsGkAtoms::code && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("|"));

   }

   else if ((aTag == nsGkAtoms::strong || aTag == nsGkAtoms::b)

            && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("*"));

   }

   else if ((aTag == nsGkAtoms::em || aTag == nsGkAtoms::i)

            && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("/"));

   }

   else if (aTag == nsGkAtoms::u && mStructs && !currentNodeIsConverted) {

     Write(NS_LITERAL_STRING("_"));

   }

   return NS_OK;

 }

 bool

 nsPlainTextSerializer::MustSuppressLeaf()

 {

   if (mIgnoredChildNodeLevel > 0) {

     return true;

   }

   if ((mTagStackIndex > 1 &&

        mTagStack[mTagStackIndex-2] == nsGkAtoms::select) ||

       (mTagStackIndex > 0 &&

         mTagStack[mTagStackIndex-1] == nsGkAtoms::select)) {

     // Don't output the contents of SELECT elements;

     // Might be nice, eventually, to output just the selected element.

     // Read more in bug 31994.

     return true;

   }

   if (mTagStackIndex > 0 &&

       (mTagStack[mTagStackIndex-1] == nsGkAtoms::script ||

        mTagStack[mTagStackIndex-1] == nsGkAtoms::style)) {

     // Don't output the contents of <script> or <style> tags;

     return true;

   }

   return false;

 }

 void

 nsPlainTextSerializer::DoAddText(bool aIsLineBreak, const nsAString& aText)

 {

   // If we don't want any output, just return

   if (!DoOutput()) {

     return;

   }

   if (!aIsLineBreak) {

     // Make sure to reset this, since it's no longer true.

     mHasWrittenCiteBlockquote = false;

   }

   if (mLineBreakDue)

     EnsureVerticalSpace(mFloatingLines);

   if (MustSuppressLeaf()) {

     return;

   }

   if (aIsLineBreak) {

     // The only times we want to pass along whitespace from the original

     // html source are if we're forced into preformatted mode via flags,

     // or if we're prettyprinting and we're inside a <pre>.

     // Otherwise, either we're collapsing to minimal text, or we're

     // prettyprinting to mimic the html format, and in neither case

     // does the formatting of the html source help us.

     if ((mFlags & nsIDocumentEncoder::OutputPreformatted) ||

         (mPreFormatted && !mWrapColumn) ||

         IsInPre()) {

       EnsureVerticalSpace(mEmptyLines+1);

     }

     else if (!mInWhitespace) {

       Write(kSpace);

       mInWhitespace = true;

     }

     return;

   }

   /* Check, if we are in a link (symbolized with mURL containing the URL)

      and the text is equal to the URL. In that case we don't want to output

      the URL twice so we scrap the text in mURL. */

   if (!mURL.IsEmpty() && mURL.Equals(aText)) {

     mURL.Truncate();

   }

   Write(aText);

 }

 nsresult

 nsPlainTextSerializer::DoAddLeaf(nsIAtom* aTag)

 {

   // If we don't want any output, just return

   if (!DoOutput()) {

     return NS_OK;

   }

   if (mLineBreakDue)

     EnsureVerticalSpace(mFloatingLines);

   if (MustSuppressLeaf()) {

     return NS_OK;

   }

   if (aTag == nsGkAtoms::br) {

     // Another egregious editor workaround, see bug 38194:

     // ignore the bogus br tags that the editor sticks here and there.

     nsAutoString tagAttr;

     if (NS_FAILED(GetAttributeValue(nsGkAtoms::type, tagAttr))

         || !tagAttr.EqualsLiteral("_moz")) {

       EnsureVerticalSpace(mEmptyLines+1);

     }

   }

   else if (aTag == nsGkAtoms::hr &&

            (mFlags & nsIDocumentEncoder::OutputFormatted)) {

     EnsureVerticalSpace(0);

     // Make a line of dashes as wide as the wrap width

     // XXX honoring percentage would be nice

     nsAutoString line;

     uint32_t width = (mWrapColumn > 0 ? mWrapColumn : 25);

     while (line.Length() < width) {

       line.Append(char16_t('-'));

     }

     Write(line);

     EnsureVerticalSpace(0);

   }

   else if (mFlags & nsIDocumentEncoder::OutputNonTextContentAsPlaceholder) {

     Write(NS_LITERAL_STRING("\xFFFC"));

   }

   else if (aTag == nsGkAtoms::img) {

     /* Output (in decreasing order of preference)

        alt, title or nothing */

     // See <http://www.w3.org/TR/REC-html40/struct/objects.html#edef-IMG>

     nsAutoString imageDescription;

     if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::alt,

                                        imageDescription))) {

       // If the alt attribute has an empty value (|alt=""|), output nothing

     }

     else if (NS_SUCCEEDED(GetAttributeValue(nsGkAtoms::title,

                                             imageDescription))

              && !imageDescription.IsEmpty()) {

       imageDescription = NS_LITERAL_STRING(" [") +

                          imageDescription +

                          NS_LITERAL_STRING("] ");

     }

     Write(imageDescription);

   }

   return NS_OK;

 }

 /**

  * Adds as many newline as necessary to get |noOfRows| empty lines

  *

  * noOfRows = -1    :   Being in the middle of some line of text

  * noOfRows =  0    :   Being at the start of a line

  * noOfRows =  n>0  :   Having n empty lines before the current line.

  */

 void

 nsPlainTextSerializer::EnsureVerticalSpace(int32_t noOfRows)

 {

   // If we have something in the indent we probably want to output

   // it and it's not included in the count for empty lines so we don't

   // realize that we should start a new line.

   if (noOfRows >= 0 && !mInIndentString.IsEmpty()) {

     EndLine(false);

     mInWhitespace = true;

   }

   while(mEmptyLines < noOfRows) {

     EndLine(false);

     mInWhitespace = true;

   }

   mLineBreakDue = false;

   mFloatingLines = -1;

 }

 /**

  * This empties the current line cache without adding a NEWLINE.

  * Should not be used if line wrapping is of importance since

  * this function destroys the cache information.

  *

  * It will also write indentation and quotes if we believe us to be

  * at the start of the line.

  */

 void

 nsPlainTextSerializer::FlushLine()

 {

   if (!mCurrentLine.IsEmpty()) {

     if (mAtFirstColumn) {

       OutputQuotesAndIndent(); // XXX: Should we always do this? Bug?

     }

     Output(mCurrentLine);

     mAtFirstColumn = mAtFirstColumn && mCurrentLine.IsEmpty();

     mCurrentLine.Truncate();

     mCurrentLineWidth = 0;

   }

 }

 /**

  * Prints the text to output to our current output device (the string mOutputString).

  * The only logic here is to replace non breaking spaces with a normal space since

  * most (all?) receivers of the result won't understand the nbsp and even be

  * confused by it.

  */

 void 

 nsPlainTextSerializer::Output(nsString& aString)

 {

   if (!aString.IsEmpty()) {

     mStartedOutput = true;

   }

   if (!(mFlags & nsIDocumentEncoder::OutputPersistNBSP)) {

     // First, replace all nbsp characters with spaces,

     // which the unicode encoder won't do for us.

     aString.ReplaceChar(kNBSP, kSPACE);

   }

   mOutputString->Append(aString);

 }

 static bool

 IsSpaceStuffable(const char16_t *s)

 {

   if (s[0] == '>' || s[0] == ' ' || s[0] == kNBSP ||

       nsCRT::strncmp(s, MOZ_UTF16("From "), 5) == 0)

     return true;

   else

     return false;

 }

 /**

  * This function adds a piece of text to the current stored line. If we are

  * wrapping text and the stored line will become too long, a suitable

  * location to wrap will be found and the line that's complete will be

  * output.

  */

 void

 nsPlainTextSerializer::AddToLine(const char16_t * aLineFragment, 

                                  int32_t aLineFragmentLength)

 {

   uint32_t prefixwidth = (mCiteQuoteLevel > 0 ? mCiteQuoteLevel + 1:0)+mIndent;

   if (mLineBreakDue)

     EnsureVerticalSpace(mFloatingLines);

   int32_t linelength = mCurrentLine.Length();

   if (0 == linelength) {

     if (0 == aLineFragmentLength) {

       // Nothing at all. Are you kidding me?

       return;

     }

     if (mFlags & nsIDocumentEncoder::OutputFormatFlowed) {

       if (IsSpaceStuffable(aLineFragment)

          && mCiteQuoteLevel == 0  // We space-stuff quoted lines anyway

          )

         {

           // Space stuffing a la RFC 2646 (format=flowed).

           mCurrentLine.Append(char16_t(' '));

           if (MayWrap()) {

             mCurrentLineWidth += GetUnicharWidth(' ');

 #ifdef DEBUG_wrapping

             NS_ASSERTION(GetUnicharStringWidth(mCurrentLine.get(),

                                                mCurrentLine.Length()) ==

                          (int32_t)mCurrentLineWidth,

                          "mCurrentLineWidth and reality out of sync!");

 #endif

           }

         }

     }

     mEmptyLines=-1;

   }

   mCurrentLine.Append(aLineFragment, aLineFragmentLength);

   if (MayWrap()) {

     mCurrentLineWidth += GetUnicharStringWidth(aLineFragment,

                                                aLineFragmentLength);

 #ifdef DEBUG_wrapping

     NS_ASSERTION(GetUnicharstringWidth(mCurrentLine.get(),

                                        mCurrentLine.Length()) ==

                  (int32_t)mCurrentLineWidth,

                  "mCurrentLineWidth and reality out of sync!");

 #endif

   }

   linelength = mCurrentLine.Length();

   //  Wrap?

   if (MayWrap())

   {

 #ifdef DEBUG_wrapping

     NS_ASSERTION(GetUnicharstringWidth(mCurrentLine.get(),

                                   mCurrentLine.Length()) ==

                  (int32_t)mCurrentLineWidth,

                  "mCurrentLineWidth and reality out of sync!");

 #endif

     // Yes, wrap!

     // The "+4" is to avoid wrap lines that only would be a couple

     // of letters too long. We give this bonus only if the

     // wrapcolumn is more than 20.

     uint32_t bonuswidth = (mWrapColumn > 20) ? 4 : 0;

     // XXX: Should calculate prefixwidth with GetUnicharStringWidth

     while(mCurrentLineWidth+prefixwidth > mWrapColumn+bonuswidth) {      

       // We go from the end removing one letter at a time until

       // we have a reasonable width

       int32_t goodSpace = mCurrentLine.Length();

       uint32_t width = mCurrentLineWidth;

       while(goodSpace > 0 && (width+prefixwidth > mWrapColumn)) {

         goodSpace--;

         width -= GetUnicharWidth(mCurrentLine[goodSpace]);

       }

       goodSpace++;

       if (mLineBreaker) {

         goodSpace = mLineBreaker->Prev(mCurrentLine.get(), 

                                     mCurrentLine.Length(), goodSpace);

         if (goodSpace != NS_LINEBREAKER_NEED_MORE_TEXT &&

             nsCRT::IsAsciiSpace(mCurrentLine.CharAt(goodSpace-1))) {

           --goodSpace;    // adjust the position since line breaker returns a position next to space

         }

       }

       // fallback if the line breaker is unavailable or failed

       if (!mLineBreaker) {

         goodSpace = mWrapColumn-prefixwidth;

         while (goodSpace >= 0 &&

                !nsCRT::IsAsciiSpace(mCurrentLine.CharAt(goodSpace))) {

           goodSpace--;

         }

       }

       nsAutoString restOfLine;

       if (goodSpace == NS_LINEBREAKER_NEED_MORE_TEXT) {

         // If we don't found a good place to break, accept long line and

         // try to find another place to break

         goodSpace=(prefixwidth>mWrapColumn+1)?1:mWrapColumn-prefixwidth+1;

         if (mLineBreaker) {

           if ((uint32_t)goodSpace < mCurrentLine.Length())

             goodSpace = mLineBreaker->Next(mCurrentLine.get(), 

                                            mCurrentLine.Length(), goodSpace);

           if (goodSpace == NS_LINEBREAKER_NEED_MORE_TEXT)

             goodSpace = mCurrentLine.Length();

         }

         // fallback if the line breaker is unavailable or failed

         if (!mLineBreaker) {

           goodSpace=(prefixwidth>mWrapColumn)?1:mWrapColumn-prefixwidth;

           while (goodSpace < linelength &&

                  !nsCRT::IsAsciiSpace(mCurrentLine.CharAt(goodSpace))) {

             goodSpace++;

           }

         }

       }

       if ((goodSpace < linelength) && (goodSpace > 0)) {

         // Found a place to break

         // -1 (trim a char at the break position)

         // only if the line break was a space.

         if (nsCRT::IsAsciiSpace(mCurrentLine.CharAt(goodSpace))) {

           mCurrentLine.Right(restOfLine, linelength-goodSpace-1);

         }

         else {

           mCurrentLine.Right(restOfLine, linelength-goodSpace);

         }

         // if breaker was U+0020, it has to consider for delsp=yes support

         bool breakBySpace = mCurrentLine.CharAt(goodSpace) == ' ';

         mCurrentLine.Truncate(goodSpace); 

         EndLine(true, breakBySpace);

         mCurrentLine.Truncate();

         // Space stuff new line?

         if (mFlags & nsIDocumentEncoder::OutputFormatFlowed) {

           if (!restOfLine.IsEmpty() && IsSpaceStuffable(restOfLine.get())

               && mCiteQuoteLevel == 0  // We space-stuff quoted lines anyway

             )

           {

             // Space stuffing a la RFC 2646 (format=flowed).

             mCurrentLine.Append(char16_t(' '));

             //XXX doesn't seem to work correctly for ' '

           }

         }

         mCurrentLine.Append(restOfLine);

         mCurrentLineWidth = GetUnicharStringWidth(mCurrentLine.get(),

                                                   mCurrentLine.Length());

         linelength = mCurrentLine.Length();

         mEmptyLines = -1;

       } 

       else {

         // Nothing to do. Hopefully we get more data later

         // to use for a place to break line

         break;

       }

     }

   } 

   else {

     // No wrapping.

   }

 }

 /**

  * Outputs the contents of mCurrentLine, and resets line specific

  * variables. Also adds an indentation and prefix if there is

  * one specified. Strips ending spaces from the line if it isn't

  * preformatted.

  */

 void

 nsPlainTextSerializer::EndLine(bool aSoftlinebreak, bool aBreakBySpace)

 {

   uint32_t currentlinelength = mCurrentLine.Length();

   if (aSoftlinebreak && 0 == currentlinelength) {

     // No meaning

     return;

   }

   /* In non-preformatted mode, remove spaces from the end of the line for

    * format=flowed compatibility. Don't do this for these special cases:

    * "-- ", the signature separator (RFC 2646) shouldn't be touched and

    * "- -- ", the OpenPGP dash-escaped signature separator in inline

    * signed messages according to the OpenPGP standard (RFC 2440).

    */  

   if (!(mFlags & nsIDocumentEncoder::OutputPreformatted) &&

       !(mFlags & nsIDocumentEncoder::OutputDontRemoveLineEndingSpaces) &&

      (aSoftlinebreak || 

      !(mCurrentLine.EqualsLiteral("-- ") || mCurrentLine.EqualsLiteral("- -- ")))) {

     // Remove spaces from the end of the line.

     while(currentlinelength > 0 &&

           mCurrentLine[currentlinelength-1] == ' ') {

       --currentlinelength;

     }

     mCurrentLine.SetLength(currentlinelength);

   }

   if (aSoftlinebreak &&

      (mFlags & nsIDocumentEncoder::OutputFormatFlowed) &&

      (mIndent == 0)) {

     // Add the soft part of the soft linebreak (RFC 2646 4.1)

     // We only do this when there is no indentation since format=flowed

     // lines and indentation doesn't work well together.

     // If breaker character is ASCII space with RFC 3676 support (delsp=yes),

     // add twice space.

     if ((mFlags & nsIDocumentEncoder::OutputFormatDelSp) && aBreakBySpace)

       mCurrentLine.Append(NS_LITERAL_STRING("  "));

     else

       mCurrentLine.Append(char16_t(' '));

   }

   if (aSoftlinebreak) {

     mEmptyLines=0;

   } 

   else {

     // Hard break

     if (!mCurrentLine.IsEmpty() || !mInIndentString.IsEmpty()) {

       mEmptyLines=-1;

     }

     mEmptyLines++;

   }

   if (mAtFirstColumn) {

     // If we don't have anything "real" to output we have to

     // make sure the indent doesn't end in a space since that

     // would trick a format=flowed-aware receiver.

     bool stripTrailingSpaces = mCurrentLine.IsEmpty();

     OutputQuotesAndIndent(stripTrailingSpaces);

   }

   mCurrentLine.Append(mLineBreak);

   Output(mCurrentLine);

   mCurrentLine.Truncate();

   mCurrentLineWidth = 0;

   mAtFirstColumn=true;

   mInWhitespace=true;

   mLineBreakDue = false;

   mFloatingLines = -1;

 }

 /**

  * Outputs the calculated and stored indent and text in the indentation. That is

  * quote chars and numbers for numbered lists and such. It will also reset any

  * stored text to put in the indentation after using it.

  */

 void

 nsPlainTextSerializer::OutputQuotesAndIndent(bool stripTrailingSpaces /* = false */)

 {

   nsAutoString stringToOutput;

   // Put the mail quote "> " chars in, if appropriate:

   if (mCiteQuoteLevel > 0) {

     nsAutoString quotes;

     for(int i=0; i < mCiteQuoteLevel; i++) {

       quotes.Append(char16_t('>'));

     }

     if (!mCurrentLine.IsEmpty()) {

       /* Better don't output a space here, if the line is empty,

          in case a receiving f=f-aware UA thinks, this were a flowed line,

          which it isn't - it's just empty.

          (Flowed lines may be joined with the following one,

          so the empty line may be lost completely.) */

       quotes.Append(char16_t(' '));

     }

     stringToOutput = quotes;

     mAtFirstColumn = false;

   }

   // Indent if necessary

   int32_t indentwidth = mIndent - mInIndentString.Length();

   if (indentwidth > 0

       && (!mCurrentLine.IsEmpty() || !mInIndentString.IsEmpty())

       // Don't make empty lines look flowed

       ) {

     nsAutoString spaces;

     for (int i=0; i < indentwidth; ++i)

       spaces.Append(char16_t(' '));

     stringToOutput += spaces;

     mAtFirstColumn = false;

   }

   if (!mInIndentString.IsEmpty()) {

     stringToOutput += mInIndentString;

     mAtFirstColumn = false;

     mInIndentString.Truncate();

   }

   if (stripTrailingSpaces) {

     int32_t lineLength = stringToOutput.Length();

     while(lineLength > 0 &&

           ' ' == stringToOutput[lineLength-1]) {

       --lineLength;

     }

     stringToOutput.SetLength(lineLength);

   }

   if (!stringToOutput.IsEmpty()) {

     Output(stringToOutput);

   }

 }

 /**

  * Write a string. This is the highlevel function to use to get text output.

  * By using AddToLine, Output, EndLine and other functions it handles quotation,

  * line wrapping, indentation, whitespace compression and other things.

  */

 void

 nsPlainTextSerializer::Write(const nsAString& aStr)

 {

   // XXX Copy necessary to use nsString methods and gain

   // access to underlying buffer

   nsAutoString str(aStr);

 #ifdef DEBUG_wrapping

   printf("Write(%s): wrap col = %d\n",

          NS_ConvertUTF16toUTF8(str).get(), mWrapColumn);

 #endif

   int32_t bol = 0;

   int32_t newline;

   int32_t totLen = str.Length();

   // If the string is empty, do nothing:

   if (totLen <= 0) return;

   // For Flowed text change nbsp-ses to spaces at end of lines to allow them

   // to be cut off along with usual spaces if required. (bug #125928)

   if (mFlags & nsIDocumentEncoder::OutputFormatFlowed) {

     for (int32_t i = totLen-1; i >= 0; i--) {

       char16_t c = str[i];

       if ('\n' == c || '\r' == c || ' ' == c || '\t' == c)

         continue;

       if (kNBSP == c)

         str.Replace(i, 1, ' ');

       else

         break;

     }

   }

   // We have two major codepaths here. One that does preformatted text and one

   // that does normal formatted text. The one for preformatted text calls

   // Output directly while the other code path goes through AddToLine.

   if ((mPreFormatted && !mWrapColumn) || IsInPre()

       || ((mSpanLevel > 0 || mDontWrapAnyQuotes)

           && mEmptyLines >= 0 && str.First() == char16_t('>'))) {

     // No intelligent wrapping.

     // This mustn't be mixed with intelligent wrapping without clearing

     // the mCurrentLine buffer before!!!

     NS_ASSERTION(mCurrentLine.IsEmpty(),

                  "Mixed wrapping data and nonwrapping data on the same line");

     if (!mCurrentLine.IsEmpty()) {

       FlushLine();

     }

     // Put the mail quote "> " chars in, if appropriate.

     // Have to put it in before every line.

     while(bol<totLen) {

       bool outputQuotes = mAtFirstColumn;

       bool atFirstColumn = mAtFirstColumn;

       bool outputLineBreak = false;

       bool spacesOnly = true;

       // Find one of '\n' or '\r' using iterators since nsAString

       // doesn't have the old FindCharInSet function.

       nsAString::const_iterator iter;           str.BeginReading(iter);

       nsAString::const_iterator done_searching; str.EndReading(done_searching);

       iter.advance(bol); 

       int32_t new_newline = bol;

       newline = kNotFound;

       while(iter != done_searching) {

         if ('\n' == *iter || '\r' == *iter) {

           newline = new_newline;

           break;

         }

         if (' ' != *iter)

           spacesOnly = false;

         ++new_newline;

         ++iter;

       }

       // Done searching

       nsAutoString stringpart;

       if (newline == kNotFound) {

         // No new lines.

         stringpart.Assign(Substring(str, bol, totLen - bol));

         if (!stringpart.IsEmpty()) {

           char16_t lastchar = stringpart[stringpart.Length()-1];

           if ((lastchar == '\t') || (lastchar == ' ') ||

              (lastchar == '\r') ||(lastchar == '\n')) {

             mInWhitespace = true;

           } 

           else {

             mInWhitespace = false;

           }

         }

         mEmptyLines=-1;

         atFirstColumn = mAtFirstColumn && (totLen-bol)==0;

         bol = totLen;

       } 

       else {

         // There is a newline

         stringpart.Assign(Substring(str, bol, newline-bol));

         mInWhitespace = true;

         outputLineBreak = true;

         mEmptyLines=0;

         atFirstColumn = true;

         bol = newline+1;

         if ('\r' == *iter && bol < totLen && '\n' == *++iter) {

           // There was a CRLF in the input. This used to be illegal and

           // stripped by the parser. Apparently not anymore. Let's skip

           // over the LF.

           bol++;

         }

       }

       mCurrentLine.AssignLiteral("");

       if (mFlags & nsIDocumentEncoder::OutputFormatFlowed) {

         if ((outputLineBreak || !spacesOnly) && // bugs 261467,125928

             !stringpart.EqualsLiteral("-- ") &&

             !stringpart.EqualsLiteral("- -- "))

           stringpart.Trim(" ", false, true, true);

         if (IsSpaceStuffable(stringpart.get()) && stringpart[0] != '>')

           mCurrentLine.Append(char16_t(' '));

       }

       mCurrentLine.Append(stringpart);

       if (outputQuotes) {

         // Note: this call messes with mAtFirstColumn

         OutputQuotesAndIndent();

       }

       Output(mCurrentLine);

       if (outputLineBreak) {

         Output(mLineBreak);

       }

       mAtFirstColumn = atFirstColumn;

     }

     // Reset mCurrentLine.

     mCurrentLine.Truncate();

 #ifdef DEBUG_wrapping

     printf("No wrapping: newline is %d, totLen is %d\n",

            newline, totLen);

 #endif

     return;

   }

   // Intelligent handling of text

   // If needed, strip out all "end of lines"

   // and multiple whitespace between words

   int32_t nextpos;

   const char16_t * offsetIntoBuffer = nullptr;

   while (bol < totLen) {    // Loop over lines

     // Find a place where we may have to do whitespace compression

     nextpos = str.FindCharInSet(" \t\n\r", bol);

 #ifdef DEBUG_wrapping

     nsAutoString remaining;

     str.Right(remaining, totLen - bol);

     foo = ToNewCString(remaining);

     //    printf("Next line: bol = %d, newlinepos = %d, totLen = %d, string = '%s'\n",

     //           bol, nextpos, totLen, foo);

     nsMemory::Free(foo);

 #endif

     if (nextpos == kNotFound) {

       // The rest of the string

       offsetIntoBuffer = str.get() + bol;

       AddToLine(offsetIntoBuffer, totLen-bol);

       bol=totLen;

       mInWhitespace=false;

     } 

     else {

       // There's still whitespace left in the string

       if (nextpos != 0 && (nextpos + 1) < totLen) {

         offsetIntoBuffer = str.get() + nextpos;

         // skip '\n' if it is between CJ chars

         if (offsetIntoBuffer[0] == '\n' && IS_CJ_CHAR(offsetIntoBuffer[-1]) && IS_CJ_CHAR(offsetIntoBuffer[1])) {

           offsetIntoBuffer = str.get() + bol;

           AddToLine(offsetIntoBuffer, nextpos-bol);

           bol = nextpos + 1;

           continue;

         }

       }

       // If we're already in whitespace and not preformatted, just skip it:

       if (mInWhitespace && (nextpos == bol) && !mPreFormatted &&

           !(mFlags & nsIDocumentEncoder::OutputPreformatted)) {

         // Skip whitespace

         bol++;

         continue;

       }

       if (nextpos == bol) {

         // Note that we are in whitespace.

         mInWhitespace = true;

         offsetIntoBuffer = str.get() + nextpos;

         AddToLine(offsetIntoBuffer, 1);

         bol++;

         continue;

       }

       mInWhitespace = true;

       offsetIntoBuffer = str.get() + bol;

       if (mPreFormatted || (mFlags & nsIDocumentEncoder::OutputPreformatted)) {

         // Preserve the real whitespace character

         nextpos++;

         AddToLine(offsetIntoBuffer, nextpos-bol);

         bol = nextpos;

       } 

       else {

         // Replace the whitespace with a space

         AddToLine(offsetIntoBuffer, nextpos-bol);

         AddToLine(kSpace.get(),1);

         bol = nextpos + 1; // Let's eat the whitespace

       }

     }

   } // Continue looping over the string

 }

 /**

  * Gets the value of an attribute in a string. If the function returns

  * NS_ERROR_NOT_AVAILABLE, there was none such attribute specified.

  */

 nsresult

 nsPlainTextSerializer::GetAttributeValue(nsIAtom* aName,

                                          nsString& aValueRet)

 {

   if (mElement) {

     if (mElement->GetAttr(kNameSpaceID_None, aName, aValueRet)) {

       return NS_OK;

     }

   }

   return NS_ERROR_NOT_AVAILABLE;

 }

 /**

  * Returns true, if the element was inserted by Moz' TXT->HTML converter.

  * In this case, we should ignore it.

  */

 bool 

 nsPlainTextSerializer::IsCurrentNodeConverted()

 {

   nsAutoString value;

   nsresult rv = GetAttributeValue(nsGkAtoms::_class, value);

   return (NS_SUCCEEDED(rv) &&

           (value.EqualsIgnoreCase("moz-txt", 7) ||

            value.EqualsIgnoreCase("\"moz-txt", 8)));

 }

 // static

 nsIAtom*

 nsPlainTextSerializer::GetIdForContent(nsIContent* aContent)

 {

   if (!aContent->IsHTML()) {

     return nullptr;

   }

   nsIAtom* localName = aContent->Tag();

   return localName->IsStaticAtom() ? localName : nullptr;

 }

 /**

  * Returns true if we currently are inside a <pre>. The check is done

  * by traversing the tag stack looking for <pre> until we hit a block

  * level tag which is assumed to override any <pre>:s below it in

  * the stack. To do this correctly to a 100% would require access

  * to style which we don't support in this converter.

  */  

 bool

 nsPlainTextSerializer::IsInPre()

 {

   int32_t i = mTagStackIndex;

   while(i > 0) {

     if (mTagStack[i - 1] == nsGkAtoms::pre)

       return true;

     if (nsContentUtils::IsHTMLBlock(mTagStack[i - 1])) {

       // We assume that every other block overrides a <pre>

       return false;

     }

     --i;

   }

   // Not a <pre> in the whole stack

   return false;

 }

 /**

  * This method is required only to identify LI's inside OL.

  * Returns TRUE if we are inside an OL tag and FALSE otherwise.

  */

 bool

 nsPlainTextSerializer::IsInOL()

 {

   int32_t i = mTagStackIndex;

   while(--i >= 0) {

     if (mTagStack[i] == nsGkAtoms::ol)

       return true;

     if (mTagStack[i] == nsGkAtoms::ul) {

       // If a UL is reached first, LI belongs the UL nested in OL.

       return false;

     }

   }

   // We may reach here for orphan LI's.

   return false;

 }

 /*

   @return 0 = no header, 1 = h1, ..., 6 = h6

 */

 int32_t HeaderLevel(nsIAtom* aTag)

 {

   if (aTag == nsGkAtoms::h1) {

     return 1;

   }

   if (aTag == nsGkAtoms::h2) {

     return 2;

   }

   if (aTag == nsGkAtoms::h3) {

     return 3;

   }

   if (aTag == nsGkAtoms::h4) {

     return 4;

   }

   if (aTag == nsGkAtoms::h5) {

     return 5;

   }

   if (aTag == nsGkAtoms::h6) {

     return 6;

   }

   return 0;

 }

 /*

  * This is an implementation of GetUnicharWidth() and

  * GetUnicharStringWidth() as defined in

  * "The Single UNIX Specification, Version 2, The Open Group, 1997"

  * <http://www.UNIX-systems.org/online.html>

  *

  * Markus Kuhn -- 2000-02-08 -- public domain

  *

  * Minor alterations to fit Mozilla's data types by Daniel Bratell

  */

 /* These functions define the column width of an ISO 10646 character

  * as follows:

  *

  *    - The null character (U+0000) has a column width of 0.

  *

  *    - Other C0/C1 control characters and DEL will lead to a return

  *      value of -1.

  *

  *    - Non-spacing and enclosing combining characters (general

  *      category code Mn or Me in the Unicode database) have a

  *      column width of 0.

  *

  *    - Spacing characters in the East Asian Wide (W) or East Asian

  *      FullWidth (F) category as defined in Unicode Technical

  *      Report #11 have a column width of 2.

  *

  *    - All remaining characters (including all printable

  *      ISO 8859-1 and WGL4 characters, Unicode control characters,

  *      etc.) have a column width of 1.

  *

  * This implementation assumes that wchar_t characters are encoded

  * in ISO 10646.

  */

 int32_t GetUnicharWidth(char16_t ucs)

 {

   /* sorted list of non-overlapping intervals of non-spacing characters */

   static const struct interval {

     uint16_t first;

     uint16_t last;

   } combining[] = {

     { 0x0300, 0x034E }, { 0x0360, 0x0362 }, { 0x0483, 0x0486 },

     { 0x0488, 0x0489 }, { 0x0591, 0x05A1 }, { 0x05A3, 0x05B9 },

     { 0x05BB, 0x05BD }, { 0x05BF, 0x05BF }, { 0x05C1, 0x05C2 },

     { 0x05C4, 0x05C4 }, { 0x064B, 0x0655 }, { 0x0670, 0x0670 },

     { 0x06D6, 0x06E4 }, { 0x06E7, 0x06E8 }, { 0x06EA, 0x06ED },

     { 0x0711, 0x0711 }, { 0x0730, 0x074A }, { 0x07A6, 0x07B0 },

     { 0x0901, 0x0902 }, { 0x093C, 0x093C }, { 0x0941, 0x0948 },

     { 0x094D, 0x094D }, { 0x0951, 0x0954 }, { 0x0962, 0x0963 },

     { 0x0981, 0x0981 }, { 0x09BC, 0x09BC }, { 0x09C1, 0x09C4 },

     { 0x09CD, 0x09CD }, { 0x09E2, 0x09E3 }, { 0x0A02, 0x0A02 },

     { 0x0A3C, 0x0A3C }, { 0x0A41, 0x0A42 }, { 0x0A47, 0x0A48 },

     { 0x0A4B, 0x0A4D }, { 0x0A70, 0x0A71 }, { 0x0A81, 0x0A82 },

     { 0x0ABC, 0x0ABC }, { 0x0AC1, 0x0AC5 }, { 0x0AC7, 0x0AC8 },

     { 0x0ACD, 0x0ACD }, { 0x0B01, 0x0B01 }, { 0x0B3C, 0x0B3C },

     { 0x0B3F, 0x0B3F }, { 0x0B41, 0x0B43 }, { 0x0B4D, 0x0B4D },

     { 0x0B56, 0x0B56 }, { 0x0B82, 0x0B82 }, { 0x0BC0, 0x0BC0 },

     { 0x0BCD, 0x0BCD }, { 0x0C3E, 0x0C40 }, { 0x0C46, 0x0C48 },

     { 0x0C4A, 0x0C4D }, { 0x0C55, 0x0C56 }, { 0x0CBF, 0x0CBF },

     { 0x0CC6, 0x0CC6 }, { 0x0CCC, 0x0CCD }, { 0x0D41, 0x0D43 },

     { 0x0D4D, 0x0D4D }, { 0x0DCA, 0x0DCA }, { 0x0DD2, 0x0DD4 },

     { 0x0DD6, 0x0DD6 }, { 0x0E31, 0x0E31 }, { 0x0E34, 0x0E3A },

     { 0x0E47, 0x0E4E }, { 0x0EB1, 0x0EB1 }, { 0x0EB4, 0x0EB9 },

     { 0x0EBB, 0x0EBC }, { 0x0EC8, 0x0ECD }, { 0x0F18, 0x0F19 },

     { 0x0F35, 0x0F35 }, { 0x0F37, 0x0F37 }, { 0x0F39, 0x0F39 },

     { 0x0F71, 0x0F7E }, { 0x0F80, 0x0F84 }, { 0x0F86, 0x0F87 },

     { 0x0F90, 0x0F97 }, { 0x0F99, 0x0FBC }, { 0x0FC6, 0x0FC6 },

     { 0x102D, 0x1030 }, { 0x1032, 0x1032 }, { 0x1036, 0x1037 },

     { 0x1039, 0x1039 }, { 0x1058, 0x1059 }, { 0x17B7, 0x17BD },

     { 0x17C6, 0x17C6 }, { 0x17C9, 0x17D3 }, { 0x18A9, 0x18A9 },

     { 0x20D0, 0x20E3 }, { 0x302A, 0x302F }, { 0x3099, 0x309A },

     { 0xFB1E, 0xFB1E }, { 0xFE20, 0xFE23 }

   };

   int32_t min = 0;

   int32_t max = sizeof(combining) / sizeof(struct interval) - 1;

   int32_t mid;

   /* test for 8-bit control characters */

   if (ucs == 0)

     return 0;

   if (ucs < 32 || (ucs >= 0x7f && ucs < 0xa0))

     return -1;

   /* first quick check for Latin-1 etc. characters */

   if (ucs < combining[0].first)

     return 1;

   /* binary search in table of non-spacing characters */

   while (max >= min) {

     mid = (min + max) / 2;

     if (combining[mid].last < ucs)

       min = mid + 1;

     else if (combining[mid].first > ucs)

       max = mid - 1;

     else if (combining[mid].first <= ucs && combining[mid].last >= ucs)

       return 0;

   }

   /* if we arrive here, ucs is not a combining or C0/C1 control character */

   /* fast test for majority of non-wide scripts */

   if (ucs < 0x1100)

     return 1;

   return 1 +

     ((ucs >= 0x1100 && ucs <= 0x115f) || /* Hangul Jamo */

      (ucs >= 0x2e80 && ucs <= 0xa4cf && (ucs & ~0x0011) != 0x300a &&

       ucs != 0x303f) ||                  /* CJK ... Yi */

      (ucs >= 0xac00 && ucs <= 0xd7a3) || /* Hangul Syllables */

      (ucs >= 0xf900 && ucs <= 0xfaff) || /* CJK Compatibility Ideographs */

      (ucs >= 0xfe30 && ucs <= 0xfe6f) || /* CJK Compatibility Forms */

      (ucs >= 0xff00 && ucs <= 0xff5f) || /* Fullwidth Forms */

      (ucs >= 0xffe0 && ucs <= 0xffe6));

 }

 int32_t GetUnicharStringWidth(const char16_t* pwcs, int32_t n)

 {

   int32_t w, width = 0;

   for (;*pwcs && n-- > 0; pwcs++)

     if ((w = GetUnicharWidth(*pwcs)) < 0)

       ++width; // Taking 1 as the width of non-printable character, for bug# 94475.

     else

       width += w;

   return width;

 }