/indra/llui/lltextbase.cpp

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/** 
 * @file lltextbase.cpp
 * @author Martin Reddy
 * @brief The base class of text box/editor, providing Url handling support
 *
 * $LicenseInfo:firstyear=2009&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2009-2010, Linden Research, Inc.
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 * 
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "linden_common.h"

#include "lltextbase.h"

#include "lllocalcliprect.h"
#include "llmenugl.h"
#include "llscrollcontainer.h"
#include "llstl.h"
#include "lltextparser.h"
#include "lltextutil.h"
#include "lltooltip.h"
#include "lluictrl.h"
#include "llurlaction.h"
#include "llurlregistry.h"
#include "llview.h"
#include "llwindow.h"
#include <boost/bind.hpp>

const F32	CURSOR_FLASH_DELAY = 1.0f;  // in seconds
const S32	CURSOR_THICKNESS = 2;

LLTextBase::line_info::line_info(S32 index_start, S32 index_end, LLRect rect, S32 line_num) 
:	mDocIndexStart(index_start), 
	mDocIndexEnd(index_end),
	mRect(rect),
	mLineNum(line_num)
{}

bool LLTextBase::compare_segment_end::operator()(const LLTextSegmentPtr& a, const LLTextSegmentPtr& b) const
{
	// sort empty spans (e.g. 11-11) after previous non-empty spans (e.g. 5-11)
	if (a->getEnd() == b->getEnd())
	{
		return a->getStart() < b->getStart();
	}
	else
	{
		return a->getEnd() < b->getEnd();
	}
}


// helper functors
struct LLTextBase::compare_bottom
{
	bool operator()(const S32& a, const LLTextBase::line_info& b) const
	{
		return a > b.mRect.mBottom; // bottom of a is higher than bottom of b
	}

	bool operator()(const LLTextBase::line_info& a, const S32& b) const
	{
		return a.mRect.mBottom > b; // bottom of a is higher than bottom of b
	}

	bool operator()(const LLTextBase::line_info& a, const LLTextBase::line_info& b) const
	{
		return a.mRect.mBottom > b.mRect.mBottom; // bottom of a is higher than bottom of b
	}

};

// helper functors
struct LLTextBase::compare_top
{
	bool operator()(const S32& a, const LLTextBase::line_info& b) const
	{
		return a > b.mRect.mTop; // top of a is higher than top of b
	}

	bool operator()(const LLTextBase::line_info& a, const S32& b) const
	{
		return a.mRect.mTop > b; // top of a is higher than top of b
	}

	bool operator()(const LLTextBase::line_info& a, const LLTextBase::line_info& b) const
	{
		return a.mRect.mTop > b.mRect.mTop; // top of a is higher than top of b
	}
};

struct LLTextBase::line_end_compare
{
	bool operator()(const S32& pos, const LLTextBase::line_info& info) const
	{
		return (pos < info.mDocIndexEnd);
	}

	bool operator()(const LLTextBase::line_info& info, const S32& pos) const
	{
		return (info.mDocIndexEnd < pos);
	}

	bool operator()(const LLTextBase::line_info& a, const LLTextBase::line_info& b) const
	{
		return (a.mDocIndexEnd < b.mDocIndexEnd);
	}

};

//////////////////////////////////////////////////////////////////////////
//
// LLTextBase
//

// register LLTextBase::Params under name "textbase"
static LLWidgetNameRegistry::StaticRegistrar sRegisterTextBaseParams(&typeid(LLTextBase::Params), "textbase");

LLTextBase::LineSpacingParams::LineSpacingParams()
:	multiple("multiple", 1.f),
	pixels("pixels", 0)
{
}


LLTextBase::Params::Params()
:	cursor_color("cursor_color"),
	text_color("text_color"),
	text_readonly_color("text_readonly_color"),
	bg_visible("bg_visible", false),
	border_visible("border_visible", false),
	bg_readonly_color("bg_readonly_color"),
	bg_writeable_color("bg_writeable_color"),
	bg_focus_color("bg_focus_color"),
	text_selected_color("text_selected_color"),
	bg_selected_color("bg_selected_color"),
	allow_scroll("allow_scroll", true),
	plain_text("plain_text",false),
	track_end("track_end", false),
	read_only("read_only", false),
	v_pad("v_pad", 0),
	h_pad("h_pad", 0),
	clip("clip", true),
	clip_partial("clip_partial", true),
	line_spacing("line_spacing"),
	max_text_length("max_length", 255),
	font_shadow("font_shadow"),
	wrap("wrap"),
	use_ellipses("use_ellipses", false),
	parse_urls("parse_urls", false),
	parse_highlights("parse_highlights", false)
{
	addSynonym(track_end, "track_bottom");
	addSynonym(wrap, "word_wrap");
	addSynonym(parse_urls, "allow_html");
}


LLTextBase::LLTextBase(const LLTextBase::Params &p) 
:	LLUICtrl(p, LLTextViewModelPtr(new LLTextViewModel)),
	mURLClickSignal(NULL),
	mMaxTextByteLength( p.max_text_length ),
	mDefaultFont(p.font),
	mFontShadow(p.font_shadow),
	mPopupMenu(NULL),
	mReadOnly(p.read_only),
	mCursorColor(p.cursor_color),
	mFgColor(p.text_color),
	mBorderVisible( p.border_visible ),
	mReadOnlyFgColor(p.text_readonly_color),
	mWriteableBgColor(p.bg_writeable_color),
	mReadOnlyBgColor(p.bg_readonly_color),
	mFocusBgColor(p.bg_focus_color),
	mTextSelectedColor(p.text_selected_color),
	mSelectedBGColor(p.bg_selected_color),
	mReflowIndex(S32_MAX),
	mCursorPos( 0 ),
	mScrollNeeded(FALSE),
	mDesiredXPixel(-1),
	mHPad(p.h_pad),
	mVPad(p.v_pad),
	mHAlign(p.font_halign),
	mVAlign(p.font_valign),
	mLineSpacingMult(p.line_spacing.multiple),
	mLineSpacingPixels(p.line_spacing.pixels),
	mClip(p.clip),
	mClipPartial(p.clip_partial && !p.allow_scroll),
	mTrackEnd( p.track_end ),
	mScrollIndex(-1),
	mSelectionStart( 0 ),
	mSelectionEnd( 0 ),
	mIsSelecting( FALSE ),
	mPlainText ( p.plain_text ),
	mWordWrap(p.wrap),
	mUseEllipses( p.use_ellipses ),
	mParseHTML(p.parse_urls),
	mParseHighlights(p.parse_highlights),
	mBGVisible(p.bg_visible),
	mScroller(NULL),
	mStyleDirty(true)
{
	if(p.allow_scroll)
	{
		LLScrollContainer::Params scroll_params;
		scroll_params.name = "text scroller";
		scroll_params.rect = getLocalRect();
		scroll_params.follows.flags = FOLLOWS_ALL;
		scroll_params.is_opaque = false;
		scroll_params.mouse_opaque = false;
		scroll_params.min_auto_scroll_rate = 200;
		scroll_params.max_auto_scroll_rate = 800;
		scroll_params.border_visible = p.border_visible;
		mScroller = LLUICtrlFactory::create<LLScrollContainer>(scroll_params);
		addChild(mScroller);
	}

	LLView::Params view_params;
	view_params.name = "text_contents";
	view_params.rect =  LLRect(0, 500, 500, 0);
	view_params.mouse_opaque = false;

	mDocumentView = LLUICtrlFactory::create<LLView>(view_params);
	if (mScroller)
	{
		mScroller->addChild(mDocumentView);
	}
	else
	{
		addChild(mDocumentView);
	}

	createDefaultSegment();

	updateRects();
}

LLTextBase::~LLTextBase()
{
	mSegments.clear();
	delete mURLClickSignal;
}

void LLTextBase::initFromParams(const LLTextBase::Params& p)
{
	LLUICtrl::initFromParams(p);
	resetDirty();		// Update saved text state
	updateSegments();

	// HACK: work around enabled == readonly design bug -- RN
	// setEnabled will modify our read only status, so do this after
	// LLTextBase::initFromParams
	if (p.read_only.isProvided())
	{
		mReadOnly = p.read_only;
	}
}

bool LLTextBase::truncate()
{
	BOOL did_truncate = FALSE;

	// First rough check - if we're less than 1/4th the size, we're OK
	if (getLength() >= S32(mMaxTextByteLength / 4))
	{	
		// Have to check actual byte size
		LLWString text(getWText());
		S32 utf8_byte_size = wstring_utf8_length(text);
		if ( utf8_byte_size > mMaxTextByteLength )
		{
			// Truncate safely in UTF-8
			std::string temp_utf8_text = wstring_to_utf8str(text);
			temp_utf8_text = utf8str_truncate( temp_utf8_text, mMaxTextByteLength );
			LLWString text = utf8str_to_wstring( temp_utf8_text );
			// remove extra bit of current string, to preserve formatting, etc.
			removeStringNoUndo(text.size(), getWText().size() - text.size());
			did_truncate = TRUE;
		}
	}

	return did_truncate;
}

const LLStyle::Params& LLTextBase::getDefaultStyleParams()
{
	//FIXME: convert mDefaultStyle to a flyweight http://www.boost.org/doc/libs/1_40_0/libs/flyweight/doc/index.html
	//and eliminate color member values
	if (mStyleDirty)
	{
		  mDefaultStyle
				  .color(LLUIColor(&mFgColor))						// pass linked color instead of copy of mFGColor
				  .readonly_color(LLUIColor(&mReadOnlyFgColor))
				  .selected_color(LLUIColor(&mTextSelectedColor))
				  .font(mDefaultFont)
				  .drop_shadow(mFontShadow);
		  mStyleDirty = false;
	}
	return mDefaultStyle;
}

void LLTextBase::onValueChange(S32 start, S32 end)
{
}


// Draws the black box behind the selected text
void LLTextBase::drawSelectionBackground()
{
	// Draw selection even if we don't have keyboard focus for search/replace
	if( hasSelection() && !mLineInfoList.empty())
	{
		std::vector<LLRect> selection_rects;

		S32 selection_left		= llmin( mSelectionStart, mSelectionEnd );
		S32 selection_right		= llmax( mSelectionStart, mSelectionEnd );
		LLRect selection_rect = mVisibleTextRect;

		// Skip through the lines we aren't drawing.
		LLRect content_display_rect = getVisibleDocumentRect();

		// binary search for line that starts before top of visible buffer
		line_list_t::const_iterator line_iter = std::lower_bound(mLineInfoList.begin(), mLineInfoList.end(), content_display_rect.mTop, compare_bottom());
		line_list_t::const_iterator end_iter = std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), content_display_rect.mBottom, compare_top());

		bool done = false;

		// Find the coordinates of the selected area
		for (;line_iter != end_iter && !done; ++line_iter)
		{
			// is selection visible on this line?
			if (line_iter->mDocIndexEnd > selection_left && line_iter->mDocIndexStart < selection_right)
			{
				segment_set_t::iterator segment_iter;
				S32 segment_offset;
				getSegmentAndOffset(line_iter->mDocIndexStart, &segment_iter, &segment_offset);
				
				LLRect selection_rect;
				selection_rect.mLeft = line_iter->mRect.mLeft;
				selection_rect.mRight = line_iter->mRect.mLeft;
				selection_rect.mBottom = line_iter->mRect.mBottom;
				selection_rect.mTop = line_iter->mRect.mTop;
					
				for(;segment_iter != mSegments.end(); ++segment_iter, segment_offset = 0)
				{
					LLTextSegmentPtr segmentp = *segment_iter;

					S32 segment_line_start = segmentp->getStart() + segment_offset;
					S32 segment_line_end = llmin(segmentp->getEnd(), line_iter->mDocIndexEnd);

					if (segment_line_start > segment_line_end) break;

					S32 segment_width = 0;
					S32 segment_height = 0;

					// if selection after beginning of segment
					if(selection_left >= segment_line_start)
					{
						S32 num_chars = llmin(selection_left, segment_line_end) - segment_line_start;
						segmentp->getDimensions(segment_offset, num_chars, segment_width, segment_height);
						selection_rect.mLeft += segment_width;
					}

					// if selection_right == segment_line_end then that means we are the first character of the next segment
					// or first character of the next line, in either case we want to add the length of the current segment
					// to the selection rectangle and continue.
					// if selection right > segment_line_end then selection spans end of current segment...
					if (selection_right >= segment_line_end)
					{
						// extend selection slightly beyond end of line
						// to indicate selection of newline character (use "n" character to determine width)
						S32 num_chars = segment_line_end - segment_line_start;
						segmentp->getDimensions(segment_offset, num_chars, segment_width, segment_height);
						selection_rect.mRight += segment_width;
					}
					// else if selection ends on current segment...
					else
					{
						S32 num_chars = selection_right - segment_line_start;
						segmentp->getDimensions(segment_offset, num_chars, segment_width, segment_height);
						selection_rect.mRight += segment_width;

						break;
					}
				}
				selection_rects.push_back(selection_rect);
			}
		}
		
		// Draw the selection box (we're using a box instead of reversing the colors on the selected text).
		gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);
		const LLColor4& color = mSelectedBGColor;
		F32 alpha = hasFocus() ? 0.7f : 0.3f;
		alpha *= getDrawContext().mAlpha;
		LLColor4 selection_color(color.mV[VRED], color.mV[VGREEN], color.mV[VBLUE], alpha);

		for (std::vector<LLRect>::iterator rect_it = selection_rects.begin();
			rect_it != selection_rects.end();
			++rect_it)
		{
			LLRect selection_rect = *rect_it;
			selection_rect.translate(mVisibleTextRect.mLeft - content_display_rect.mLeft, mVisibleTextRect.mBottom - content_display_rect.mBottom);
			gl_rect_2d(selection_rect, selection_color);
		}
	}
}

void LLTextBase::drawCursor()
{
	F32 alpha = getDrawContext().mAlpha;

	if( hasFocus()
		&& gFocusMgr.getAppHasFocus()
		&& !mReadOnly)
	{
		const LLWString &wtext = getWText();
		const llwchar* text = wtext.c_str();

		LLRect cursor_rect = getLocalRectFromDocIndex(mCursorPos);
		cursor_rect.translate(-1, 0);
		segment_set_t::iterator seg_it = getSegIterContaining(mCursorPos);

		// take style from last segment
		LLTextSegmentPtr segmentp;

		if (seg_it != mSegments.end())
		{
			segmentp = *seg_it;
		}
		else
		{
			return;
		}

		// Draw the cursor
		// (Flash the cursor every half second starting a fixed time after the last keystroke)
		F32 elapsed = mCursorBlinkTimer.getElapsedTimeF32();
		if( (elapsed < CURSOR_FLASH_DELAY ) || (S32(elapsed * 2) & 1) )
		{

			if (LL_KIM_OVERWRITE == gKeyboard->getInsertMode() && !hasSelection())
			{
				S32 segment_width = 0;
				S32 segment_height = 0;
				segmentp->getDimensions(mCursorPos - segmentp->getStart(), 1, segment_width, segment_height);
				S32 width = llmax(CURSOR_THICKNESS, segment_width);
				cursor_rect.mRight = cursor_rect.mLeft + width;
			}
			else
			{
				cursor_rect.mRight = cursor_rect.mLeft + CURSOR_THICKNESS;
			}
			
			gGL.getTexUnit(0)->unbind(LLTexUnit::TT_TEXTURE);

			LLColor4 cursor_color = mCursorColor.get() % alpha;
			gGL.color4fv( cursor_color.mV );
			
			gl_rect_2d(cursor_rect);

			if (LL_KIM_OVERWRITE == gKeyboard->getInsertMode() && !hasSelection() && text[mCursorPos] != '\n')
			{
				LLColor4 text_color;
				const LLFontGL* fontp;
				text_color = segmentp->getColor();
				fontp = segmentp->getStyle()->getFont();
				fontp->render(text, mCursorPos, cursor_rect, 
					LLColor4(1.f - text_color.mV[VRED], 1.f - text_color.mV[VGREEN], 1.f - text_color.mV[VBLUE], alpha),
					LLFontGL::LEFT, mVAlign,
					LLFontGL::NORMAL,
					LLFontGL::NO_SHADOW,
					1);
			}

			// Make sure the IME is in the right place
			LLRect screen_pos = calcScreenRect();
			LLCoordGL ime_pos( screen_pos.mLeft + llfloor(cursor_rect.mLeft), screen_pos.mBottom + llfloor(cursor_rect.mTop) );

			ime_pos.mX = (S32) (ime_pos.mX * LLUI::sGLScaleFactor.mV[VX]);
			ime_pos.mY = (S32) (ime_pos.mY * LLUI::sGLScaleFactor.mV[VY]);
			getWindow()->setLanguageTextInput( ime_pos );
		}
	}
}

void LLTextBase::drawText()
{
	const S32 text_len = getLength();
	if( text_len <= 0 )
	{
		return;
	}
	S32 selection_left = -1;
	S32 selection_right = -1;
	// Draw selection even if we don't have keyboard focus for search/replace
	if( hasSelection())
	{
		selection_left = llmin( mSelectionStart, mSelectionEnd );
		selection_right = llmax( mSelectionStart, mSelectionEnd );
	}

	std::pair<S32, S32> line_range = getVisibleLines(mClipPartial);
	S32 first_line = line_range.first;
	S32 last_line = line_range.second;
	if (first_line >= last_line)
	{
		return;
	}
	
	S32 line_start = getLineStart(first_line);
	// find first text segment that spans top of visible portion of text buffer
	segment_set_t::iterator seg_iter = getSegIterContaining(line_start);
	if (seg_iter == mSegments.end()) 
	{
		return;
	}

	LLTextSegmentPtr cur_segment = *seg_iter;

	for (S32 cur_line = first_line; cur_line < last_line; cur_line++)
	{
		S32 next_line = cur_line + 1;
		line_info& line = mLineInfoList[cur_line];

		S32 next_start = -1;
		S32 line_end = text_len;

		if (next_line < getLineCount())
		{
			next_start = getLineStart(next_line);
			line_end = next_start;
		}

		LLRect text_rect(line.mRect);
		text_rect.mRight = mDocumentView->getRect().getWidth(); // clamp right edge to document extents
		text_rect.translate(mDocumentView->getRect().mLeft, mDocumentView->getRect().mBottom); // adjust by scroll position

		// draw a single line of text
		S32 seg_start = line_start;
		while( seg_start < line_end )
		{
			while( cur_segment->getEnd() <= seg_start )
			{
				seg_iter++;
				if (seg_iter == mSegments.end())
				{
					llwarns << "Ran off the segmentation end!" << llendl;

					return;
				}
				cur_segment = *seg_iter;
			}
			
			S32 clipped_end	=	llmin( line_end, cur_segment->getEnd() )  - cur_segment->getStart();

			if (mUseEllipses								// using ellipses
				&& clipped_end == line_end					// last segment on line
				&& next_line == last_line					// this is the last visible line
				&& last_line < (S32)mLineInfoList.size())	// and there is more text to display
			{
				// more lines of text to go, but we can't fit them
				// so shrink text rect to force ellipses
				text_rect.mRight -= 2;
			}

			text_rect.mLeft = (S32)(cur_segment->draw(seg_start - cur_segment->getStart(), clipped_end, selection_left, selection_right, text_rect));

			seg_start = clipped_end + cur_segment->getStart();
		}

		line_start = next_start;
	}
}

///////////////////////////////////////////////////////////////////
// Returns change in number of characters in mWText

S32 LLTextBase::insertStringNoUndo(S32 pos, const LLWString &wstr, LLTextBase::segment_vec_t* segments )
{
	LLWString text(getWText());
	S32 old_len = text.length();		// length() returns character length
	S32 insert_len = wstr.length();

	pos = getEditableIndex(pos, true);

	segment_set_t::iterator seg_iter = getEditableSegIterContaining(pos);

	LLTextSegmentPtr default_segment;

	LLTextSegmentPtr segmentp;
	if (seg_iter != mSegments.end())
	{
		segmentp = *seg_iter;
	}
	else
	{
		//segmentp = mSegments.back();
		return pos;
	}

	if (segmentp->canEdit())
	{
		segmentp->setEnd(segmentp->getEnd() + insert_len);
		if (seg_iter != mSegments.end())
		{
			++seg_iter;
		}
	}
	else
	{
		// create default editable segment to hold new text
		LLStyleConstSP sp(new LLStyle(getDefaultStyleParams()));
		default_segment = new LLNormalTextSegment( sp, pos, pos + insert_len, *this);
	}

	// shift remaining segments to right
	for(;seg_iter != mSegments.end(); ++seg_iter)
	{
		LLTextSegmentPtr segmentp = *seg_iter;
		segmentp->setStart(segmentp->getStart() + insert_len);
		segmentp->setEnd(segmentp->getEnd() + insert_len);
	}

	// insert new segments
	if (segments)
	{
		if (default_segment.notNull())
		{
			// potentially overwritten by segments passed in
			insertSegment(default_segment);
		}
		for (segment_vec_t::iterator seg_iter = segments->begin();
			seg_iter != segments->end();
			++seg_iter)
		{
			LLTextSegment* segmentp = *seg_iter;
			insertSegment(segmentp);
		}
	}

	text.insert(pos, wstr);
	getViewModel()->setDisplay(text);

	if ( truncate() )
	{
		insert_len = getLength() - old_len;
	}

	onValueChange(pos, pos + insert_len);
	needsReflow(pos);

	return insert_len;
}

S32 LLTextBase::removeStringNoUndo(S32 pos, S32 length)
{
	LLWString text(getWText());
	segment_set_t::iterator seg_iter = getSegIterContaining(pos);
	while(seg_iter != mSegments.end())
	{
		LLTextSegmentPtr segmentp = *seg_iter;
		S32 end = pos + length;
		if (segmentp->getStart() < pos)
		{
			// deleting from middle of segment
			if (segmentp->getEnd() > end)
			{
				segmentp->setEnd(segmentp->getEnd() - length);
			}
			// truncating segment
			else
			{
				segmentp->setEnd(pos);
			}
		}
		else if (segmentp->getStart() < end)
		{
			// deleting entire segment
			if (segmentp->getEnd() <= end)
			{
				// remove segment
				segmentp->unlinkFromDocument(this);
				segment_set_t::iterator seg_to_erase(seg_iter++);
				mSegments.erase(seg_to_erase);
				continue;
			}
			// deleting head of segment
			else
			{
				segmentp->setStart(pos);
				segmentp->setEnd(segmentp->getEnd() - length);
			}
		}
		else
		{
			// shifting segments backward to fill deleted portion
			segmentp->setStart(segmentp->getStart() - length);
			segmentp->setEnd(segmentp->getEnd() - length);
		}
		++seg_iter;
	}

	text.erase(pos, length);
	getViewModel()->setDisplay(text);

	// recreate default segment in case we erased everything
	createDefaultSegment();

	onValueChange(pos, pos);
	needsReflow(pos);

	return -length;	// This will be wrong if someone calls removeStringNoUndo with an excessive length
}

S32 LLTextBase::overwriteCharNoUndo(S32 pos, llwchar wc)
{
	if (pos > (S32)getLength())
	{
		return 0;
	}
	LLWString text(getWText());
	text[pos] = wc;
	getViewModel()->setDisplay(text);

	onValueChange(pos, pos + 1);
	needsReflow(pos);

	return 1;
}


void LLTextBase::createDefaultSegment()
{
	// ensures that there is always at least one segment
	if (mSegments.empty())
	{
		LLStyleConstSP sp(new LLStyle(getDefaultStyleParams()));
		LLTextSegmentPtr default_segment = new LLNormalTextSegment( sp, 0, getLength() + 1, *this);
		mSegments.insert(default_segment);
		default_segment->linkToDocument(this);
	}
}

void LLTextBase::insertSegment(LLTextSegmentPtr segment_to_insert)
{
	if (segment_to_insert.isNull()) 
	{
		return;
	}

	segment_set_t::iterator cur_seg_iter = getSegIterContaining(segment_to_insert->getStart());
	S32 reflow_start_index = 0;

	if (cur_seg_iter == mSegments.end())
	{
		mSegments.insert(segment_to_insert);
		segment_to_insert->linkToDocument(this);
		reflow_start_index = segment_to_insert->getStart();
	}
	else
	{
		LLTextSegmentPtr cur_segmentp = *cur_seg_iter;
		reflow_start_index = cur_segmentp->getStart();
		if (cur_segmentp->getStart() < segment_to_insert->getStart())
		{
			S32 old_segment_end = cur_segmentp->getEnd();
			// split old at start point for new segment
			cur_segmentp->setEnd(segment_to_insert->getStart());
			// advance to next segment
			// insert remainder of old segment
			LLStyleConstSP sp = cur_segmentp->getStyle();
			LLTextSegmentPtr remainder_segment = new LLNormalTextSegment( sp, segment_to_insert->getStart(), old_segment_end, *this);
			mSegments.insert(cur_seg_iter, remainder_segment);
			remainder_segment->linkToDocument(this);
			// insert new segment before remainder of old segment
			mSegments.insert(cur_seg_iter, segment_to_insert);

			segment_to_insert->linkToDocument(this);
			// at this point, there will be two overlapping segments owning the text
			// associated with the incoming segment
		}
		else
		{
			mSegments.insert(cur_seg_iter, segment_to_insert);
			segment_to_insert->linkToDocument(this);
		}

		// now delete/truncate remaining segments as necessary
		// cur_seg_iter points to segment before incoming segment
		while(cur_seg_iter != mSegments.end())
		{
			cur_segmentp = *cur_seg_iter;
			if (cur_segmentp == segment_to_insert) 
			{
				++cur_seg_iter;
				continue;
			}

			if (cur_segmentp->getStart() >= segment_to_insert->getStart())
			{
				if(cur_segmentp->getEnd() <= segment_to_insert->getEnd())
				{
					cur_segmentp->unlinkFromDocument(this);
					// grab copy of iterator to erase, and bump it
					segment_set_t::iterator seg_to_erase(cur_seg_iter++);
					mSegments.erase(seg_to_erase);
					continue;
				}
				else
				{
					// last overlapping segment, clip to end of incoming segment
					// and stop traversal
					cur_segmentp->setStart(segment_to_insert->getEnd());
					break;
				}
			}
			++cur_seg_iter;
		}
	}

	// layout potentially changed
	needsReflow(reflow_start_index);
}

BOOL LLTextBase::handleMouseDown(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleMouseDown(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleMouseDown(x, y, mask);
}

BOOL LLTextBase::handleMouseUp(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleMouseUp(x, y, mask))
	{
		// Did we just click on a link?
		if (mURLClickSignal
			&& cur_segment->getStyle()
			&& cur_segment->getStyle()->isLink())
		{
			// *TODO: send URL here?
			(*mURLClickSignal)(this, LLSD() );
		}
		return TRUE;
	}

	return LLUICtrl::handleMouseUp(x, y, mask);
}

BOOL LLTextBase::handleMiddleMouseDown(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleMiddleMouseDown(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleMiddleMouseDown(x, y, mask);
}

BOOL LLTextBase::handleMiddleMouseUp(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleMiddleMouseUp(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleMiddleMouseUp(x, y, mask);
}

BOOL LLTextBase::handleRightMouseDown(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleRightMouseDown(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleRightMouseDown(x, y, mask);
}

BOOL LLTextBase::handleRightMouseUp(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleRightMouseUp(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleRightMouseUp(x, y, mask);
}

BOOL LLTextBase::handleDoubleClick(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleDoubleClick(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleDoubleClick(x, y, mask);
}

BOOL LLTextBase::handleHover(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleHover(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleHover(x, y, mask);
}

BOOL LLTextBase::handleScrollWheel(S32 x, S32 y, S32 clicks)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleScrollWheel(x, y, clicks))
	{
		return TRUE;
	}

	return LLUICtrl::handleScrollWheel(x, y, clicks);
}

BOOL LLTextBase::handleToolTip(S32 x, S32 y, MASK mask)
{
	LLTextSegmentPtr cur_segment = getSegmentAtLocalPos(x, y);
	if (cur_segment && cur_segment->handleToolTip(x, y, mask))
	{
		return TRUE;
	}

	return LLUICtrl::handleToolTip(x, y, mask);
}


void LLTextBase::reshape(S32 width, S32 height, BOOL called_from_parent)
{
	if (width != getRect().getWidth() || height != getRect().getHeight())
	{
		bool scrolled_to_bottom = mScroller ? mScroller->isAtBottom() : false;

		LLUICtrl::reshape( width, height, called_from_parent );

		if (mScroller && scrolled_to_bottom && mTrackEnd)
		{
			// keep bottom of text buffer visible
			// do this here as well as in reflow to handle case
			// where shrinking from top, which causes buffer to temporarily 
			// not be scrolled to the bottom, since the scroll index
			// specified the _top_ of the visible document region
			mScroller->goToBottom();
		}

		// do this first after reshape, because other things depend on
		// up-to-date mVisibleTextRect
		updateRects();
		
		needsReflow();
	}
}

void LLTextBase::draw()
{
	// reflow if needed, on demand
	reflow();

	// then update scroll position, as cursor may have moved
	if (!mReadOnly)
	{
		updateScrollFromCursor();
	}

	LLRect text_rect;
	if (mScroller)
	{
		mScroller->localRectToOtherView(mScroller->getContentWindowRect(), &text_rect, this);
	}
	else
	{
		LLRect visible_lines_rect;
		std::pair<S32, S32> line_range = getVisibleLines(mClipPartial);
		for (S32 i = line_range.first; i < line_range.second; i++)
		{
			if (visible_lines_rect.isEmpty())
			{
				visible_lines_rect = mLineInfoList[i].mRect;
			}
			else
			{
				visible_lines_rect.unionWith(mLineInfoList[i].mRect);
			}
		}
		text_rect = visible_lines_rect;
		text_rect.translate(mDocumentView->getRect().mLeft, mDocumentView->getRect().mBottom);
	}

	if (mBGVisible)
	{
		F32 alpha = getCurrentTransparency();
		// clip background rect against extents, if we support scrolling
		LLRect bg_rect = mVisibleTextRect;
		if (mScroller)
		{
			bg_rect.intersectWith(text_rect);
		}
		LLColor4 bg_color = mReadOnly 
							? mReadOnlyBgColor.get()
							: hasFocus() 
								? mFocusBgColor.get() 
								: mWriteableBgColor.get();
		gl_rect_2d(text_rect, bg_color % alpha, TRUE);
	}

	bool should_clip = mClip || mScroller != NULL;
	{ LLLocalClipRect clip(text_rect, should_clip);
 
		// draw document view
		if (mScroller)
		{
			drawChild(mScroller);
		}
		else
		{
			drawChild(mDocumentView);
		}
 
		drawSelectionBackground();
		drawText();
		drawCursor();
	}
 
	mDocumentView->setVisible(FALSE);
	LLUICtrl::draw();
	mDocumentView->setVisible(TRUE);
}


//virtual
void LLTextBase::setColor( const LLColor4& c )
{
	mFgColor = c;
	mStyleDirty = true;
}

//virtual 
void LLTextBase::setReadOnlyColor(const LLColor4 &c)
{
	mReadOnlyFgColor = c;
	mStyleDirty = true;
}

//virtual
void LLTextBase::handleVisibilityChange( BOOL new_visibility )
{
	if(!new_visibility && mPopupMenu)
	{
		mPopupMenu->hide();
	}
	LLUICtrl::handleVisibilityChange(new_visibility);
}

//virtual
void LLTextBase::setValue(const LLSD& value )
{
	setText(value.asString());
}

//virtual
BOOL LLTextBase::canDeselect() const 
{ 
	return hasSelection(); 
}


//virtual
void LLTextBase::deselect()
{
	mSelectionStart = 0;
	mSelectionEnd = 0;
	mIsSelecting = FALSE;
}


// Sets the scrollbar from the cursor position
void LLTextBase::updateScrollFromCursor()
{
	// Update scroll position even in read-only mode (when there's no cursor displayed)
	// because startOfDoc()/endOfDoc() modify cursor position. See EXT-736.

	if (!mScrollNeeded || !mScroller)
	{
		return;
	}
	mScrollNeeded = FALSE; 

	// scroll so that the cursor is at the top of the page
	LLRect scroller_doc_window = getVisibleDocumentRect();
	LLRect cursor_rect_doc = getDocRectFromDocIndex(mCursorPos);
	mScroller->scrollToShowRect(cursor_rect_doc, LLRect(0, scroller_doc_window.getHeight() - 5, scroller_doc_window.getWidth(), 5));
}

S32 LLTextBase::getLeftOffset(S32 width)
{
	switch (mHAlign)
	{
	case LLFontGL::LEFT:
		return mHPad;
	case LLFontGL::HCENTER:
		return mHPad + llmax(0, (mVisibleTextRect.getWidth() - width - mHPad) / 2);
	case LLFontGL::RIGHT:
		return mVisibleTextRect.getWidth() - width;
	default:
		return mHPad;
	}
}


static LLFastTimer::DeclareTimer FTM_TEXT_REFLOW ("Text Reflow");
void LLTextBase::reflow()
{
	LLFastTimer ft(FTM_TEXT_REFLOW);

	updateSegments();

	if (mReflowIndex == S32_MAX)
	{
		return;
	}

	bool scrolled_to_bottom = mScroller ? mScroller->isAtBottom() : false;

	LLRect cursor_rect = getLocalRectFromDocIndex(mCursorPos);
	bool follow_selection = getLocalRect().overlaps(cursor_rect); // cursor is (potentially) visible

	// store in top-left relative coordinates to avoid issues with horizontal scrollbar appearing and disappearing
	cursor_rect.mTop = mVisibleTextRect.mTop - cursor_rect.mTop;
	cursor_rect.mBottom = mVisibleTextRect.mTop - cursor_rect.mBottom;

	S32 first_line = getFirstVisibleLine();

	// if scroll anchor not on first line, update it to first character of first line
	if ((first_line < mLineInfoList.size())
		&&	(mScrollIndex <  mLineInfoList[first_line].mDocIndexStart
			||	mScrollIndex >= mLineInfoList[first_line].mDocIndexEnd))
	{
		mScrollIndex = mLineInfoList[first_line].mDocIndexStart;
	}
	LLRect first_char_rect = getLocalRectFromDocIndex(mScrollIndex);
	// store in top-left relative coordinates to avoid issues with horizontal scrollbar appearing and disappearing
	first_char_rect.mTop = mVisibleTextRect.mTop - first_char_rect.mTop;
	first_char_rect.mBottom = mVisibleTextRect.mTop - first_char_rect.mBottom;

	S32 reflow_count = 0;
	while(mReflowIndex < S32_MAX)
	{
		// we can get into an infinite loop if the document height does not monotonically increase
		// with decreasing width (embedded ui elements with alternate layouts).  In that case, 
		// we want to stop reflowing after 2 iterations.  We use 2, since we need to handle the case
		// of introducing a vertical scrollbar causing a reflow with less width.  We should also always
		// use an even number of iterations to avoid user visible oscillation of the layout
		if(++reflow_count > 2)
		{
			lldebugs << "Breaking out of reflow due to possible infinite loop in " << getName() << llendl;
			break;
		}
	
		S32 start_index = mReflowIndex;
		mReflowIndex = S32_MAX;

		// shrink document to minimum size (visible portion of text widget)
		// to force inlined widgets with follows set to shrink
		mDocumentView->reshape(mVisibleTextRect.getWidth(), mDocumentView->getRect().getHeight());

		S32 cur_top = 0;

		segment_set_t::iterator seg_iter = mSegments.begin();
		S32 seg_offset = 0;
		S32 line_start_index = 0;
		const S32 text_available_width = mVisibleTextRect.getWidth() - mHPad;  // reserve room for margin
		S32 remaining_pixels = text_available_width;
		S32 line_count = 0;

		// find and erase line info structs starting at start_index and going to end of document
		if (!mLineInfoList.empty())
		{
			// find first element whose end comes after start_index
			line_list_t::iterator iter = std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), start_index, line_end_compare());
			line_start_index = iter->mDocIndexStart;
			line_count = iter->mLineNum;
			cur_top = iter->mRect.mTop;
			getSegmentAndOffset(iter->mDocIndexStart, &seg_iter, &seg_offset);
			mLineInfoList.erase(iter, mLineInfoList.end());
		}

		S32 line_height = 0;

		while(seg_iter != mSegments.end())
		{
			LLTextSegmentPtr segment = *seg_iter;

			// track maximum height of any segment on this line
			S32 cur_index = segment->getStart() + seg_offset;

			// ask segment how many character fit in remaining space
			S32 character_count = segment->getNumChars(getWordWrap() ? llmax(0, remaining_pixels) : S32_MAX,
														seg_offset, 
														cur_index - line_start_index, 
														S32_MAX);

			S32 segment_width, segment_height;
			bool force_newline = segment->getDimensions(seg_offset, character_count, segment_width, segment_height);
			// grow line height as necessary based on reported height of this segment
			line_height = llmax(line_height, segment_height);
			remaining_pixels -= segment_width;

			seg_offset += character_count;

			S32 last_segment_char_on_line = segment->getStart() + seg_offset;

			S32 text_actual_width = text_available_width - remaining_pixels;
			S32 text_left = getLeftOffset(text_actual_width);
			LLRect line_rect(text_left, 
							cur_top, 
							text_left + text_actual_width, 
							cur_top - line_height);

			// if we didn't finish the current segment...
			if (last_segment_char_on_line < segment->getEnd())
			{
				// add line info and keep going
				mLineInfoList.push_back(line_info(
											line_start_index, 
											last_segment_char_on_line, 
											line_rect, 
											line_count));

				line_start_index = segment->getStart() + seg_offset;
				cur_top -= llround((F32)line_height * mLineSpacingMult) + mLineSpacingPixels;
				remaining_pixels = text_available_width;
				line_height = 0;
			}
			// ...just consumed last segment..
			else if (++segment_set_t::iterator(seg_iter) == mSegments.end())
			{
				mLineInfoList.push_back(line_info(
											line_start_index, 
											last_segment_char_on_line, 
											line_rect, 
											line_count));
				cur_top -= llround((F32)line_height * mLineSpacingMult) + mLineSpacingPixels;
				break;
			}
			// ...or finished a segment and there are segments remaining on this line
			else
			{
				// subtract pixels used and increment segment
				if (force_newline)
				{
					mLineInfoList.push_back(line_info(
												line_start_index, 
												last_segment_char_on_line, 
												line_rect, 
												line_count));
					line_start_index = segment->getStart() + seg_offset;
					cur_top -= llround((F32)line_height * mLineSpacingMult) + mLineSpacingPixels;
					line_height = 0;
					remaining_pixels = text_available_width;
				}
				++seg_iter;
				seg_offset = 0;
			}
			if (force_newline) 
			{
				line_count++;
			}
		}

		// calculate visible region for diplaying text
		updateRects();

		for (segment_set_t::iterator segment_it = mSegments.begin();
			segment_it != mSegments.end();
			++segment_it)
		{
			LLTextSegmentPtr segmentp = *segment_it;
			segmentp->updateLayout(*this);

		}
	}

	// apply scroll constraints after reflowing text
	if (!hasMouseCapture() && mScroller)
	{
		if (scrolled_to_bottom && mTrackEnd)
		{
			// keep bottom of text buffer visible
			endOfDoc();
		}
		else if (hasSelection() && follow_selection)
		{
			// keep cursor in same vertical position on screen when selecting text
			LLRect new_cursor_rect_doc = getDocRectFromDocIndex(mCursorPos);
			LLRect old_cursor_rect = cursor_rect;
			old_cursor_rect.mTop = mVisibleTextRect.mTop - cursor_rect.mTop;
			old_cursor_rect.mBottom = mVisibleTextRect.mTop - cursor_rect.mBottom;

			mScroller->scrollToShowRect(new_cursor_rect_doc, old_cursor_rect);
		}
		else
		{
			// keep first line of text visible
			LLRect new_first_char_rect = getDocRectFromDocIndex(mScrollIndex);

			// pass in desired rect in the coordinate frame of the document viewport
			LLRect old_first_char_rect = first_char_rect;
			old_first_char_rect.mTop = mVisibleTextRect.mTop - first_char_rect.mTop;
			old_first_char_rect.mBottom = mVisibleTextRect.mTop - first_char_rect.mBottom;

			mScroller->scrollToShowRect(new_first_char_rect, old_first_char_rect);
		}
	}

	// reset desired x cursor position
	updateCursorXPos();
}

LLRect LLTextBase::getTextBoundingRect()
{
	reflow();
	return mTextBoundingRect;
}


void LLTextBase::clearSegments()
{
	mSegments.clear();
	createDefaultSegment();
}

S32 LLTextBase::getLineStart( S32 line ) const
{
	S32 num_lines = getLineCount();
	if (num_lines == 0)
	{
		return 0;
	}

	line = llclamp(line, 0, num_lines-1);
	return mLineInfoList[line].mDocIndexStart;
}

S32 LLTextBase::getLineEnd( S32 line ) const
{
	S32 num_lines = getLineCount();
	if (num_lines == 0)
	{
		return 0;
	}

	line = llclamp(line, 0, num_lines-1);
	return mLineInfoList[line].mDocIndexEnd;
}



S32 LLTextBase::getLineNumFromDocIndex( S32 doc_index, bool include_wordwrap) const
{
	if (mLineInfoList.empty())
	{
		return 0;
	}
	else
	{
		line_list_t::const_iterator iter = std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), doc_index, line_end_compare());
		if (include_wordwrap)
		{
			return iter - mLineInfoList.begin();
		}
		else
		{
			if (iter == mLineInfoList.end())
			{
				return mLineInfoList.back().mLineNum;
			}
			else
			{
				return iter->mLineNum;
			}
		}
	}
}

// Given an offset into text (pos), find the corresponding line (from the start of the doc) and an offset into the line.
S32 LLTextBase::getLineOffsetFromDocIndex( S32 startpos, bool include_wordwrap) const
{
	if (mLineInfoList.empty())
	{
		return startpos;
	}
	else
	{
		line_list_t::const_iterator iter = std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), startpos, line_end_compare());
		return startpos - iter->mDocIndexStart;
	}
}

S32	LLTextBase::getFirstVisibleLine() const
{
	LLRect visible_region = getVisibleDocumentRect();

	// binary search for line that starts before top of visible buffer
	line_list_t::const_iterator iter = std::lower_bound(mLineInfoList.begin(), mLineInfoList.end(), visible_region.mTop, compare_bottom());

	return iter - mLineInfoList.begin();
}

std::pair<S32, S32>	LLTextBase::getVisibleLines(bool require_fully_visible) 
{
	LLRect visible_region = getVisibleDocumentRect();
	line_list_t::const_iterator first_iter;
	line_list_t::const_iterator last_iter;

	// make sure we have an up-to-date mLineInfoList
	reflow();

	if (require_fully_visible)
	{
		first_iter = std::lower_bound(mLineInfoList.begin(), mLineInfoList.end(), visible_region.mTop, compare_top());
		last_iter = std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), visible_region.mBottom, compare_bottom());
	}
	else
	{
		first_iter = std::upper_bound(mLineInfoList.begin(), mLineInfoList.end(), visible_region.mTop, compare_bottom());
		last_iter = std::lower_bound(mLineInfoList.begin(), mLineInfoList.end(), visible_region.mBottom, compare_top());
	}
	return std::pair<S32, S32>(first_iter - mLineInfoList.begin(), last_iter - mLineInfoList.begin());
}



LLTextViewModel* LLTextBase::getViewModel() const
{
	return (LLTextViewModel*)mViewModel.get();
}

void LLTextBase::addDocumentChild(LLView* view) 
{ 
	mDocumentView->addChild(view); 
}

void LLTextBase::removeDocumentChild(LLView* view) 
{ 
	mDocumentView->removeChild(view); 
}


static LLFastTimer::DeclareTimer FTM_UPDATE_TEXT_SEGMENTS("Update Text Segments");
void LLTextBase::updateSegments()
{
	LLFastTimer ft(FTM_UPDATE_TEXT_SEGMENTS);
	createDefaultSegment();
}

void LLTextBase::getSegmentAndOffset( S32 startpos, segment_set_t::const_iterator* seg_iter, S32* offsetp ) const
{
	*seg_iter = getSegIterContaining(startpos);
	if (*seg_iter == mSegments.end())
	{
		*offsetp = 0;
	}
	else
	{
		*offsetp = startpos - (**seg_iter)->getStart();
	}
}

void LLTextBase::getSegmentAndOffset( S32 startpos, segment_set_t::iterator* seg_iter, S32* offsetp )
{
	*seg_iter = getSegIterContaining(startpos);
	if (*seg_iter == mSegments.end())
	{
		*offsetp = 0;
	}
	else
	{
		*offsetp = startpos - (**seg_iter)->getStart();
	}
}

LLTextBase::segment_set_t::iterator LLTextBase::getEditableSegIterContaining(S32 index)
{
	segment_set_t::iterator it = getSegIterContaining(index);
	segment_set_t::iterator orig_it = it;

	if (it == mSegments.end()) return it;

	if (!(*it)->canEdit() 
		&& index == (*it)->getStart() 
		&& it != mSegments.begin())
	{
		it--;
		if ((*it)->canEdit())
		{
			return it;
		}
	}
	return orig_it;
}

LLTextBase::segment_set_t::const_iterator LLTextBase::getEditableSegIterContaining(S32 index) const
{
	segment_set_t::const_iterator it = getSegIterContaining(index);
	segment_set_t::const_iterator orig_it = it;
	if (it == mSegments.end()) return it;

	if (!(*it)->canEdit() 
		&& index == (*it)->getStart() 
		&& it != mSegments.begin())
	{
		it--;
		if ((*it)->canEdit())
		{
			return it;
		}
	}
	return orig_it;
}

LLTextBase::segment_set_t::iterator LLTextBase::getSegIterContaining(S32 index)
{

	static LLPointer<LLIndexSegment> index_segment = new LLIndexSegment();

	if (index > getLength()) { return mSegments.end(); }

	// when there are no segments, we return the end iterator, which must be checked by caller
	if (mSegments.size() <= 1) { return mSegments.begin(); }

	//FIXME: avoid operator new somehow (without running into refcount problems)
	index_segment->setStart(index);
	index_segment->setEnd(index);
	segment_set_t::iterator it = mSegments.upper_bound(index_segment);
	return it;
}

LLTextBase::segment_set_t::const_iterator LLTextBase::getSegIterContaining(S32 index) const
{
	static LLPointer<LLIndexSegment> index_segment = new LLIndexSegment();

	if (index > getLength()) { return mSegments.end(); }

	// when there are no segments, we return the end iterator, which must be checked by caller
	if (mSegments.size() <= 1) { return mSegments.begin(); }

	index_segment->setStart(index);
	index_segment->setEnd(index);
	LLTextBase::segment_set_t::const_iterator it =  mSegments.upper_bound(index_segment);
	return it;
}

// Finds the text segment (if any) at the give local screen position
LLTextSegmentPtr LLTextBase::getSegmentAtLocalPos( S32 x, S32 y, bool hit_past_end_of_line)
{
	// Find the cursor position at the requested local screen position
	S32 offset = getDocIndexFromLocalCoord( x, y, FALSE, hit_past_end_of_line);
	segment_set_t::iterator seg_iter = getSegIterContaining(offset);
	if (seg_iter != mSegments.end())
	{
		return *seg_iter;
	}
	else
	{
		return LLTextSegmentPtr();
	}
}

void LLTextBase::createUrlContextMenu(S32 x, S32 y, const std::string &in_url)
{
	// work out the XUI menu file to use for this url
	LLUrlMatch match;
	std::string url = in_url;
	if (! LLUrlRegistry::instance().findUrl(url, match))
	{
		return;
	}
	
	std::string xui_file = match.getMenuName();
	if (xui_file.empty())
	{
		return;
	}

	// set up the callbacks for all of the potential menu items, N.B. we
	// don't use const ref strings in callbacks in case url goes out of scope
	LLUICtrl::CommitCallbackRegistry::ScopedRegistrar registrar;
	registrar.add("Url.Open", boost::bind(&LLUrlAction::openURL, url));
	registrar.add("Url.OpenInternal", boost::bind(&LLUrlAction::openURLInternal, url));
	registrar.add("Url.OpenExternal", boost::bind(&LLUrlAction::openURLExternal, url));
	registrar.add("Url.Execute", boost::bind(&LLUrlAction::executeSLURL, url));
	registrar.add("Url.Teleport", boost::bind(&LLUrlAction::teleportToLocation, url));
	registrar.add("Url.ShowProfile", boost::bind(&LLUrlAction::showProfile, url));
	registrar.add("Url.ShowOnMap", boost::bind(&LLUrlAction::showLocationOnMap, url));
	registrar.add("Url.CopyLabel", boost::bind(&LLUrlAction::copyLabelToClipboard, url));
	registrar.add("Url.CopyUrl", boost::bind(&LLUrlAction::copyURLToClipboard, url));

	// create and return the context menu from the XUI file
	delete mPopupMenu;
	mPopupMenu = LLUICtrlFactory::getInstance()->createFromFile<LLContextMenu>(xui_file, LLMenuGL::sMenuContainer,
																		 LLMenuHolderGL::child_registry_t::instance());	
	if (mPopupMenu)
	{
		mPopupMenu->show(x, y);
		LLMenuGL::showPopup(this, mPopupMenu, x, y);
	}
}

void LLTextBase::setText(const LLStringExplicit &utf8str, const LLStyle::Params& input_params)
{
	// clear out the existing text and segments
	getViewModel()->setDisplay(LLWStringUtil::null);

	clearSegments();
//	createDefaultSegment();

	deselect();

	// append the new text (supports Url linking)
	std::string text(utf8str);
	LLStringUtil::removeCRLF(text);

	// appendText modifies mCursorPos...
	appendText(text, false, input_params);
	// ...so move cursor to top after appending text
	if (!mTrackEnd)
	{
		startOfDoc();
	}

	onValueChange(0, getLength());
}

//virtual
std::string LLTextBase::getText() const
{
	return getViewModel()->getValue().asString();
}

// IDEVO - icons can be UI image names or UUID sent from
// server with avatar display name
static LLUIImagePtr image_from_icon_name(const std::string& icon_name)
{
	if (LLUUID::validate(icon_name))
	{
		return LLUI::getUIImageByID( LLUUID(icon_name) );
	}
	else
	{
		return LLUI::getUIImage(icon_name);
	}
}

void LLTextBase::appendTextImpl(const std::string &new_text, const LLStyle::Params& input_params)
{
	LLStyle::Params style_params(input_params);
	style_params.fillFrom(getDefaultStyleParams());

	S32 part = (S32)LLTextParser::WHOLE;
	if (mParseHTML && !style_params.is_link) // Don't search for URLs inside a link segment (STORM-358).
	{
		S32 start=0,end=0;
		LLUrlMatch match;
		std::string text = new_text;
		while ( LLUrlRegistry::instance().findUrl(text, match,
				boost::bind(&LLTextBase::replaceUrl, this, _1, _2, _3)) )
		{
			
			LLTextUtil::processUrlMatch(&match,this);

			start = match.getStart();
			end = match.getEnd()+1;

			LLStyle::Params link_params(style_params);
			link_params.overwriteFrom(match.getStyle());

			// output the text before the Url
			if (start > 0)
			{
				if (part == (S32)LLTextParser::WHOLE ||
					part == (S32)LLTextParser::START)
				{
					part = (S32)LLTextParser::START;
				}
				else
				{
					part = (S32)LLTextParser::MIDDLE;
				}
				std::string subtext=text.substr(0,start);
				appendAndHighlightText(subtext, part, style_params); 
			}
			// output the styled Url
			appendAndHighlightTextImpl(match.getLabel(), part, link_params, match.underlineOnHoverOnly());
			
			// set the tooltip for the Url label
			if (! match.getTooltip().empty())
			{
				segment_set_t::iterator it = getSegIterContaining(getLength()-1);
				if (it != mSegments.end())
					{
						LLTextSegmentPtr segment = *it;
						segment->setToolTip(match.getTooltip());
					}
			}

			// move on to the rest of the text after the Url
			if (end < (S32)text.length()) 
			{
				text = text.substr(end,text.length() - end);
				end=0;
				part=(S32)LLTextParser::END;
			}
			else
			{
				break;
			}
		}
		if (part != (S32)LLTextParser::WHOLE) 
			part=(S32)LLTextParser::END;
		if (end < (S32)text.length()) 
			appendAndHighlightText(text, part, style_params);		
	}
	else
	{
		appendAndHighlightText(new_text, part, style_params);
	}
}

void LLTextBase::appendText(const std::string &new_text, bool prepend_newline, const LLStyle::Params& input_params)
{
	if (new_text.empty()) 
		return;

	if(prepend_newline)
		appendLineBreakSegment(input_params);
	appendTextImpl(new_text,input_params);
}

void LLTextBase::needsReflow(S32 index)
{
	lldebugs << "reflow on object " << (void*)this << " index = " << mReflowIndex << ", new index = " << index << llendl;
	mReflowIndex = llmin(mReflowIndex, index);
}

void LLTextBase::appendLineBreakSegment(const LLStyle::Params& style_params)
{
	segment_vec_t segments;
	LLStyleConstSP sp(new LLStyle(style_params));
	segments.push_back(new LLLineBreakTextSegment(sp, getLength()));

	insertStringNoUndo(getLength(), utf8str_to_wstring("\n"), &segments);
}

void LLTextBase::appendImageSegment(const LLStyle::Params& style_params)
{
	if(getPlainText())
	{
		return;
	}
	segment_vec_t segments;
	LLStyleConstSP sp(new LLStyle(style_params));
	segments.push_back(new LLImageTextSegment(sp, getLength(),*this));

	insertStringNoUndo(getLength(), utf8str_to_wstring(" "), &segments);
}

void LLTextBase::appendWidget(const LLInlineViewSegment::Params& params, const std::string& text, bool allow_undo)
{
	segment_vec_t segments;
	LLWString widget_wide_text = utf8str_to_wstring(text);
	segmen…