1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
5 // This file implements utility functions for eliding and formatting UI text.
7 // Note that several of the functions declared in text_elider.h are implemented
8 // in this file using helper classes in an unnamed namespace.
10 #include "ui/gfx/text_elider.h"
15 #include "base/files/file_path.h"
16 #include "base/i18n/break_iterator.h"
17 #include "base/i18n/char_iterator.h"
18 #include "base/i18n/rtl.h"
19 #include "base/memory/scoped_ptr.h"
20 #include "base/strings/string_split.h"
21 #include "base/strings/string_util.h"
22 #include "base/strings/sys_string_conversions.h"
23 #include "base/strings/utf_string_conversions.h"
24 #include "third_party/icu/source/common/unicode/rbbi.h"
25 #include "third_party/icu/source/common/unicode/uloc.h"
26 #include "ui/gfx/font_list.h"
27 #include "ui/gfx/text_utils.h"
29 using base::ASCIIToUTF16;
30 using base::UTF8ToUTF16;
31 using base::WideToUTF16;
36 const char kEllipsis[] = "\xE2\x80\xA6";
37 const base::char16 kEllipsisUTF16[] = { 0x2026, 0 };
38 const base::char16 kForwardSlash = '/';
40 StringSlicer::StringSlicer(const base::string16& text,
41 const base::string16& ellipsis,
43 bool elide_at_beginning)
46 elide_in_middle_(elide_in_middle),
47 elide_at_beginning_(elide_at_beginning) {
50 base::string16 StringSlicer::CutString(size_t length, bool insert_ellipsis) {
51 const base::string16 ellipsis_text = insert_ellipsis ? ellipsis_
54 if (elide_at_beginning_)
55 return ellipsis_text +
56 text_.substr(FindValidBoundaryBefore(text_.length() - length));
58 if (!elide_in_middle_)
59 return text_.substr(0, FindValidBoundaryBefore(length)) + ellipsis_text;
61 // We put the extra character, if any, before the cut.
62 const size_t half_length = length / 2;
63 const size_t prefix_length = FindValidBoundaryBefore(length - half_length);
64 const size_t suffix_start_guess = text_.length() - half_length;
65 const size_t suffix_start = FindValidBoundaryAfter(suffix_start_guess);
66 const size_t suffix_length =
67 half_length - (suffix_start_guess - suffix_start);
68 return text_.substr(0, prefix_length) + ellipsis_text +
69 text_.substr(suffix_start, suffix_length);
72 size_t StringSlicer::FindValidBoundaryBefore(size_t index) const {
73 DCHECK_LE(index, text_.length());
74 if (index != text_.length())
75 U16_SET_CP_START(text_.data(), 0, index);
79 size_t StringSlicer::FindValidBoundaryAfter(size_t index) const {
80 DCHECK_LE(index, text_.length());
81 if (index != text_.length())
82 U16_SET_CP_LIMIT(text_.data(), 0, index, text_.length());
86 base::string16 ElideEmail(const base::string16& email,
87 const FontList& font_list,
88 float available_pixel_width) {
89 if (GetStringWidthF(email, font_list) <= available_pixel_width)
92 // Split the email into its local-part (username) and domain-part. The email
93 // spec technically allows for @ symbols in the local-part (username) of the
94 // email under some special requirements. It is guaranteed that there is no @
95 // symbol in the domain part of the email however so splitting at the last @
97 const size_t split_index = email.find_last_of('@');
98 DCHECK_NE(split_index, base::string16::npos);
99 base::string16 username = email.substr(0, split_index);
100 base::string16 domain = email.substr(split_index + 1);
101 DCHECK(!username.empty());
102 DCHECK(!domain.empty());
104 // Subtract the @ symbol from the available width as it is mandatory.
105 const base::string16 kAtSignUTF16 = ASCIIToUTF16("@");
106 available_pixel_width -= GetStringWidthF(kAtSignUTF16, font_list);
108 // Check whether eliding the domain is necessary: if eliding the username
109 // is sufficient, the domain will not be elided.
110 const float full_username_width = GetStringWidthF(username, font_list);
111 const float available_domain_width =
112 available_pixel_width -
113 std::min(full_username_width,
114 GetStringWidthF(username.substr(0, 1) + kEllipsisUTF16,
116 if (GetStringWidthF(domain, font_list) > available_domain_width) {
117 // Elide the domain so that it only takes half of the available width.
118 // Should the username not need all the width available in its half, the
119 // domain will occupy the leftover width.
120 // If |desired_domain_width| is greater than |available_domain_width|: the
121 // minimal username elision allowed by the specifications will not fit; thus
122 // |desired_domain_width| must be <= |available_domain_width| at all cost.
123 const float desired_domain_width =
124 std::min(available_domain_width,
125 std::max(available_pixel_width - full_username_width,
126 available_pixel_width / 2));
127 domain = ElideText(domain, font_list, desired_domain_width,
129 // Failing to elide the domain such that at least one character remains
130 // (other than the ellipsis itself) remains: return a single ellipsis.
131 if (domain.length() <= 1U)
132 return base::string16(kEllipsisUTF16);
135 // Fit the username in the remaining width (at this point the elided username
136 // is guaranteed to fit with at least one character remaining given all the
137 // precautions taken earlier).
138 available_pixel_width -= GetStringWidthF(domain, font_list);
139 username = ElideText(username, font_list, available_pixel_width,
142 return username + kAtSignUTF16 + domain;
145 base::string16 ElideFilename(const base::FilePath& filename,
146 const FontList& font_list,
147 float available_pixel_width) {
149 base::string16 filename_utf16 = filename.value();
150 base::string16 extension = filename.Extension();
151 base::string16 rootname = filename.BaseName().RemoveExtension().value();
152 #elif defined(OS_POSIX)
153 base::string16 filename_utf16 = WideToUTF16(base::SysNativeMBToWide(
155 base::string16 extension = WideToUTF16(base::SysNativeMBToWide(
156 filename.Extension()));
157 base::string16 rootname = WideToUTF16(base::SysNativeMBToWide(
158 filename.BaseName().RemoveExtension().value()));
161 const float full_width = GetStringWidthF(filename_utf16, font_list);
162 if (full_width <= available_pixel_width)
163 return base::i18n::GetDisplayStringInLTRDirectionality(filename_utf16);
165 if (rootname.empty() || extension.empty()) {
166 const base::string16 elided_name = ElideText(filename_utf16, font_list,
167 available_pixel_width, ELIDE_AT_END);
168 return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
171 const float ext_width = GetStringWidthF(extension, font_list);
172 const float root_width = GetStringWidthF(rootname, font_list);
174 // We may have trimmed the path.
175 if (root_width + ext_width <= available_pixel_width) {
176 const base::string16 elided_name = rootname + extension;
177 return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
180 if (ext_width >= available_pixel_width) {
181 const base::string16 elided_name = ElideText(
182 rootname + extension, font_list, available_pixel_width,
184 return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
187 float available_root_width = available_pixel_width - ext_width;
188 base::string16 elided_name =
189 ElideText(rootname, font_list, available_root_width, ELIDE_AT_END);
190 elided_name += extension;
191 return base::i18n::GetDisplayStringInLTRDirectionality(elided_name);
194 base::string16 ElideText(const base::string16& text,
195 const FontList& font_list,
196 float available_pixel_width,
197 ElideBehavior elide_behavior) {
201 const float current_text_pixel_width = GetStringWidthF(text, font_list);
202 const bool elide_in_middle = (elide_behavior == ELIDE_IN_MIDDLE);
203 const bool elide_at_beginning = (elide_behavior == ELIDE_AT_BEGINNING);
204 const bool insert_ellipsis = (elide_behavior != TRUNCATE_AT_END);
206 const base::string16 ellipsis = base::string16(kEllipsisUTF16);
207 StringSlicer slicer(text, ellipsis, elide_in_middle, elide_at_beginning);
209 // Pango will return 0 width for absurdly long strings. Cut the string in
210 // half and try again.
211 // This is caused by an int overflow in Pango (specifically, in
212 // pango_glyph_string_extents_range). It's actually more subtle than just
213 // returning 0, since on super absurdly long strings, the int can wrap and
214 // return positive numbers again. Detecting that is probably not worth it
215 // (eliding way too much from a ridiculous string is probably still
216 // ridiculous), but we should check other widths for bogus values as well.
217 if (current_text_pixel_width <= 0 && !text.empty()) {
218 const base::string16 cut =
219 slicer.CutString(text.length() / 2, insert_ellipsis);
220 return ElideText(cut, font_list, available_pixel_width, elide_behavior);
223 if (current_text_pixel_width <= available_pixel_width)
226 if (insert_ellipsis &&
227 GetStringWidthF(ellipsis, font_list) > available_pixel_width)
228 return base::string16();
230 // Use binary search to compute the elided text.
232 size_t hi = text.length() - 1;
234 for (guess = (lo + hi) / 2; lo <= hi; guess = (lo + hi) / 2) {
235 // We check the width of the whole desired string at once to ensure we
236 // handle kerning/ligatures/etc. correctly.
237 // TODO(skanuj) : Handle directionality of ellipsis based on adjacent
238 // characters. See crbug.com/327963.
239 const base::string16 cut = slicer.CutString(guess, insert_ellipsis);
240 const float guess_width = GetStringWidthF(cut, font_list);
241 if (guess_width == available_pixel_width)
243 if (guess_width > available_pixel_width) {
245 // Move back if we are on loop terminating condition, and guess is wider
254 return slicer.CutString(guess, insert_ellipsis);
257 bool ElideString(const base::string16& input, int max_len,
258 base::string16* output) {
259 DCHECK_GE(max_len, 0);
260 if (static_cast<int>(input.length()) <= max_len) {
261 output->assign(input);
270 output->assign(input.substr(0, 1));
273 output->assign(input.substr(0, 2));
276 output->assign(input.substr(0, 1) + ASCIIToUTF16(".") +
277 input.substr(input.length() - 1));
280 output->assign(input.substr(0, 1) + ASCIIToUTF16("..") +
281 input.substr(input.length() - 1));
284 int rstr_len = (max_len - 3) / 2;
285 int lstr_len = rstr_len + ((max_len - 3) % 2);
286 output->assign(input.substr(0, lstr_len) + ASCIIToUTF16("...") +
287 input.substr(input.length() - rstr_len));
297 // Internal class used to track progress of a rectangular string elide
298 // operation. Exists so the top-level ElideRectangleString() function
299 // can be broken into smaller methods sharing this state.
300 class RectangleString {
302 RectangleString(size_t max_rows, size_t max_cols,
303 bool strict, base::string16 *output)
304 : max_rows_(max_rows),
312 // Perform deferred initializations following creation. Must be called
313 // before any input can be added via AddString().
314 void Init() { output_->clear(); }
316 // Add an input string, reformatting to fit the desired dimensions.
317 // AddString() may be called multiple times to concatenate together
318 // multiple strings into the region (the current caller doesn't do
320 void AddString(const base::string16& input);
322 // Perform any deferred output processing. Must be called after the
323 // last AddString() call has occurred.
327 // Add a line to the rectangular region at the current position,
328 // either by itself or by breaking it into words.
329 void AddLine(const base::string16& line);
331 // Add a word to the rectangular region at the current position,
332 // either by itself or by breaking it into characters.
333 void AddWord(const base::string16& word);
335 // Add text to the output string if the rectangular boundaries
336 // have not been exceeded, advancing the current position.
337 void Append(const base::string16& string);
339 // Set the current position to the beginning of the next line. If
340 // |output| is true, add a newline to the output string if the rectangular
341 // boundaries have not been exceeded. If |output| is false, we assume
342 // some other mechanism will (likely) do similar breaking after the fact.
343 void NewLine(bool output);
345 // Maximum number of rows allowed in the output string.
348 // Maximum number of characters allowed in the output string.
351 // Current row position, always incremented and may exceed max_rows_
352 // when the input can not fit in the region. We stop appending to
353 // the output string, however, when this condition occurs. In the
354 // future, we may want to expose this value to allow the caller to
355 // determine how many rows would actually be required to hold the
359 // Current character position, should never exceed max_cols_.
362 // True when we do whitespace to newline conversions ourselves.
365 // True when some of the input has been truncated.
368 // String onto which the output is accumulated.
369 base::string16* output_;
371 DISALLOW_COPY_AND_ASSIGN(RectangleString);
374 void RectangleString::AddString(const base::string16& input) {
375 base::i18n::BreakIterator lines(input,
376 base::i18n::BreakIterator::BREAK_NEWLINE);
378 while (lines.Advance())
379 AddLine(lines.GetString());
381 NOTREACHED() << "BreakIterator (lines) init failed";
385 bool RectangleString::Finalize() {
387 output_->append(ASCIIToUTF16("..."));
393 void RectangleString::AddLine(const base::string16& line) {
394 if (line.length() < max_cols_) {
397 base::i18n::BreakIterator words(line,
398 base::i18n::BreakIterator::BREAK_SPACE);
400 while (words.Advance())
401 AddWord(words.GetString());
403 NOTREACHED() << "BreakIterator (words) init failed";
406 // Account for naturally-occuring newlines.
411 void RectangleString::AddWord(const base::string16& word) {
412 if (word.length() < max_cols_) {
413 // Word can be made to fit, no need to fragment it.
414 if (current_col_ + word.length() >= max_cols_)
418 // Word is so big that it must be fragmented.
421 base::i18n::UTF16CharIterator chars(&word);
422 while (!chars.end()) {
423 // When boundary is hit, add as much as will fit on this line.
424 if (current_col_ + (chars.char_pos() - char_start) >= max_cols_) {
425 Append(word.substr(array_start, chars.array_pos() - array_start));
427 array_start = chars.array_pos();
428 char_start = chars.char_pos();
432 // Add the last remaining fragment, if any.
433 if (array_start != chars.array_pos())
434 Append(word.substr(array_start, chars.array_pos() - array_start));
438 void RectangleString::Append(const base::string16& string) {
439 if (current_row_ < max_rows_)
440 output_->append(string);
443 current_col_ += string.length();
446 void RectangleString::NewLine(bool output) {
447 if (current_row_ < max_rows_) {
449 output_->append(ASCIIToUTF16("\n"));
457 // Internal class used to track progress of a rectangular text elide
458 // operation. Exists so the top-level ElideRectangleText() function
459 // can be broken into smaller methods sharing this state.
460 class RectangleText {
462 RectangleText(const FontList& font_list,
463 float available_pixel_width,
464 int available_pixel_height,
465 WordWrapBehavior wrap_behavior,
466 std::vector<base::string16>* lines)
467 : font_list_(font_list),
468 line_height_(font_list.GetHeight()),
469 available_pixel_width_(available_pixel_width),
470 available_pixel_height_(available_pixel_height),
471 wrap_behavior_(wrap_behavior),
474 last_line_ended_in_lf_(false),
476 insufficient_width_(false),
477 insufficient_height_(false) {}
479 // Perform deferred initializions following creation. Must be called
480 // before any input can be added via AddString().
481 void Init() { lines_->clear(); }
483 // Add an input string, reformatting to fit the desired dimensions.
484 // AddString() may be called multiple times to concatenate together
485 // multiple strings into the region (the current caller doesn't do
487 void AddString(const base::string16& input);
489 // Perform any deferred output processing. Must be called after the last
490 // AddString() call has occured. Returns a combination of
491 // |ReformattingResultFlags| indicating whether the given width or height was
492 // insufficient, leading to elision or truncation.
496 // Add a line to the rectangular region at the current position,
497 // either by itself or by breaking it into words.
498 void AddLine(const base::string16& line);
500 // Wrap the specified word across multiple lines.
501 int WrapWord(const base::string16& word);
503 // Add a long word - wrapping, eliding or truncating per the wrap behavior.
504 int AddWordOverflow(const base::string16& word);
506 // Add a word to the rectangluar region at the current position.
507 int AddWord(const base::string16& word);
509 // Append the specified |text| to the current output line, incrementing the
510 // running width by the specified amount. This is an optimization over
511 // |AddToCurrentLine()| when |text_width| is already known.
512 void AddToCurrentLineWithWidth(const base::string16& text, float text_width);
514 // Append the specified |text| to the current output line.
515 void AddToCurrentLine(const base::string16& text);
517 // Set the current position to the beginning of the next line.
520 // The font list used for measuring text width.
521 const FontList& font_list_;
523 // The height of each line of text.
524 const int line_height_;
526 // The number of pixels of available width in the rectangle.
527 const float available_pixel_width_;
529 // The number of pixels of available height in the rectangle.
530 const int available_pixel_height_;
532 // The wrap behavior for words that are too long to fit on a single line.
533 const WordWrapBehavior wrap_behavior_;
535 // The current running width.
536 float current_width_;
538 // The current running height.
541 // The current line of text.
542 base::string16 current_line_;
544 // Indicates whether the last line ended with \n.
545 bool last_line_ended_in_lf_;
547 // The output vector of lines.
548 std::vector<base::string16>* lines_;
550 // Indicates whether a word was so long that it had to be truncated or elided
551 // to fit the available width.
552 bool insufficient_width_;
554 // Indicates whether there were too many lines for the available height.
555 bool insufficient_height_;
557 DISALLOW_COPY_AND_ASSIGN(RectangleText);
560 void RectangleText::AddString(const base::string16& input) {
561 base::i18n::BreakIterator lines(input,
562 base::i18n::BreakIterator::BREAK_NEWLINE);
564 while (!insufficient_height_ && lines.Advance()) {
565 base::string16 line = lines.GetString();
566 // The BREAK_NEWLINE iterator will keep the trailing newline character,
567 // except in the case of the last line, which may not have one. Remove
568 // the newline character, if it exists.
569 last_line_ended_in_lf_ = !line.empty() && line[line.length() - 1] == '\n';
570 if (last_line_ended_in_lf_)
571 line.resize(line.length() - 1);
575 NOTREACHED() << "BreakIterator (lines) init failed";
579 int RectangleText::Finalize() {
580 // Remove trailing whitespace from the last line or remove the last line
581 // completely, if it's just whitespace.
582 if (!insufficient_height_ && !lines_->empty()) {
583 TrimWhitespace(lines_->back(), TRIM_TRAILING, &lines_->back());
584 if (lines_->back().empty() && !last_line_ended_in_lf_)
587 if (last_line_ended_in_lf_)
588 lines_->push_back(base::string16());
589 return (insufficient_width_ ? INSUFFICIENT_SPACE_HORIZONTAL : 0) |
590 (insufficient_height_ ? INSUFFICIENT_SPACE_VERTICAL : 0);
593 void RectangleText::AddLine(const base::string16& line) {
594 const float line_width = GetStringWidthF(line, font_list_);
595 if (line_width <= available_pixel_width_) {
596 AddToCurrentLineWithWidth(line, line_width);
598 // Iterate over positions that are valid to break the line at. In general,
599 // these are word boundaries but after any punctuation following the word.
600 base::i18n::BreakIterator words(line,
601 base::i18n::BreakIterator::BREAK_LINE);
603 while (words.Advance()) {
604 const bool truncate = !current_line_.empty();
605 const base::string16& word = words.GetString();
606 const int lines_added = AddWord(word);
609 // Trim trailing whitespace from the line that was added.
610 const int line = lines_->size() - lines_added;
611 TrimWhitespace(lines_->at(line), TRIM_TRAILING, &lines_->at(line));
613 if (ContainsOnlyWhitespace(word)) {
614 // Skip the first space if the previous line was carried over.
616 current_line_.clear();
621 NOTREACHED() << "BreakIterator (words) init failed";
624 // Account for naturally-occuring newlines.
628 int RectangleText::WrapWord(const base::string16& word) {
629 // Word is so wide that it must be fragmented.
630 base::string16 text = word;
632 bool first_fragment = true;
633 while (!insufficient_height_ && !text.empty()) {
634 base::string16 fragment =
635 ElideText(text, font_list_, available_pixel_width_,
637 // At least one character has to be added at every line, even if the
638 // available space is too small.
640 fragment = text.substr(0, 1);
641 if (!first_fragment && NewLine())
643 AddToCurrentLine(fragment);
644 text = text.substr(fragment.length());
645 first_fragment = false;
650 int RectangleText::AddWordOverflow(const base::string16& word) {
653 // Unless this is the very first word, put it on a new line.
654 if (!current_line_.empty()) {
660 if (wrap_behavior_ == IGNORE_LONG_WORDS) {
661 current_line_ = word;
662 current_width_ = available_pixel_width_;
663 } else if (wrap_behavior_ == WRAP_LONG_WORDS) {
664 lines_added += WrapWord(word);
666 const ElideBehavior elide_behavior =
667 (wrap_behavior_ == ELIDE_LONG_WORDS ? ELIDE_AT_END : TRUNCATE_AT_END);
668 const base::string16 elided_word =
669 ElideText(word, font_list_, available_pixel_width_, elide_behavior);
670 AddToCurrentLine(elided_word);
671 insufficient_width_ = true;
677 int RectangleText::AddWord(const base::string16& word) {
679 base::string16 trimmed;
680 TrimWhitespace(word, TRIM_TRAILING, &trimmed);
681 const float trimmed_width = GetStringWidthF(trimmed, font_list_);
682 if (trimmed_width <= available_pixel_width_) {
683 // Word can be made to fit, no need to fragment it.
684 if ((current_width_ + trimmed_width > available_pixel_width_) && NewLine())
686 // Append the non-trimmed word, in case more words are added after.
687 AddToCurrentLine(word);
689 lines_added = AddWordOverflow(wrap_behavior_ == IGNORE_LONG_WORDS ?
695 void RectangleText::AddToCurrentLine(const base::string16& text) {
696 AddToCurrentLineWithWidth(text, GetStringWidthF(text, font_list_));
699 void RectangleText::AddToCurrentLineWithWidth(const base::string16& text,
701 if (current_height_ >= available_pixel_height_) {
702 insufficient_height_ = true;
705 current_line_.append(text);
706 current_width_ += text_width;
709 bool RectangleText::NewLine() {
710 bool line_added = false;
711 if (current_height_ < available_pixel_height_) {
712 lines_->push_back(current_line_);
713 current_line_.clear();
716 insufficient_height_ = true;
718 current_height_ += line_height_;
725 bool ElideRectangleString(const base::string16& input, size_t max_rows,
726 size_t max_cols, bool strict,
727 base::string16* output) {
728 RectangleString rect(max_rows, max_cols, strict, output);
730 rect.AddString(input);
731 return rect.Finalize();
734 int ElideRectangleText(const base::string16& input,
735 const FontList& font_list,
736 float available_pixel_width,
737 int available_pixel_height,
738 WordWrapBehavior wrap_behavior,
739 std::vector<base::string16>* lines) {
740 RectangleText rect(font_list,
741 available_pixel_width,
742 available_pixel_height,
746 rect.AddString(input);
747 return rect.Finalize();
750 base::string16 TruncateString(const base::string16& string, size_t length) {
751 if (string.size() <= length)
752 // String fits, return it.
756 // No room for the elide string, return an empty string.
757 return base::string16();
759 size_t max = length - 1;
761 // Added to the end of strings that are too big.
762 static const base::char16 kElideString[] = { 0x2026, 0 };
765 // Just enough room for the elide string.
768 // Use a line iterator to find the first boundary.
769 UErrorCode status = U_ZERO_ERROR;
770 scoped_ptr<icu::RuleBasedBreakIterator> bi(
771 static_cast<icu::RuleBasedBreakIterator*>(
772 icu::RuleBasedBreakIterator::createLineInstance(
773 icu::Locale::getDefault(), status)));
774 if (U_FAILURE(status))
775 return string.substr(0, max) + kElideString;
776 bi->setText(string.c_str());
777 int32_t index = bi->preceding(static_cast<int32_t>(max));
778 if (index == icu::BreakIterator::DONE) {
779 index = static_cast<int32_t>(max);
781 // Found a valid break (may be the beginning of the string). Now use
782 // a character iterator to find the previous non-whitespace character.
783 icu::StringCharacterIterator char_iterator(string.c_str());
785 // No valid line breaks. Start at the end again. This ensures we break
786 // on a valid character boundary.
787 index = static_cast<int32_t>(max);
789 char_iterator.setIndex(index);
790 while (char_iterator.hasPrevious()) {
791 char_iterator.previous();
792 if (!(u_isspace(char_iterator.current()) ||
793 u_charType(char_iterator.current()) == U_CONTROL_CHAR ||
794 u_charType(char_iterator.current()) == U_NON_SPACING_MARK)) {
795 // Not a whitespace character. Advance the iterator so that we
796 // include the current character in the truncated string.
797 char_iterator.next();
801 if (char_iterator.hasPrevious()) {
802 // Found a valid break point.
803 index = char_iterator.getIndex();
805 // String has leading whitespace, return the elide string.
809 return string.substr(0, index) + kElideString;