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#615 Force output of text rather than throw upon infinite loop.
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Also move sanity checks for LineBreakContext to class and make them asserts.
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@danfickle
danfickle committed Dec 11, 2020
1 parent d7fdf63 commit 7400d52
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Showing 5 changed files with 149 additions and 111 deletions.
36 changes: 25 additions & 11 deletions openhtmltopdf-core/src/main/java/com/openhtmltopdf/layout/Breaker.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -122,7 +122,8 @@ public static BreakTextResult breakText(
int avail,
CalculatedStyle style,
boolean tryToBreakAnywhere,
int lineWidth) {
int lineWidth,
boolean forceOutput) {

FSFont font = style.getFSFont(c);
IdentValue whitespace = style.getWhitespace();
Expand All @@ -132,21 +133,24 @@ public static BreakTextResult breakText(
// ====== handle nowrap
if (whitespace == IdentValue.NOWRAP) {
int width = Breaker.getTextWidthWithLetterSpacing(c, font, context.getMaster(), letterSpacing);
if (width <= avail) {
if (width <= avail || forceOutput) {
c.setLineBreakedBecauseOfNoWrap(false);
context.setEnd(context.getLast());
context.setWidth(width);
context.setNeedsNewLine(false);
return BreakTextResult.FINISHED;
} else if (!c.isLineBreakedBecauseOfNoWrap()) {
c.setLineBreakedBecauseOfNoWrap(true);
context.setEnd(context.getStart());
context.setWidth(0);
context.setNeedsNewLine(true);
context.setUnbreakable(true);
return BreakTextResult.DANGER_RECONSUME_WORD_ON_NL;
} else {
c.setLineBreakedBecauseOfNoWrap(false);
context.setEnd(context.getLast());
context.setWidth(width);
context.setNeedsNewLine(false);
return BreakTextResult.FINISHED;
}
}
Expand All @@ -164,6 +168,7 @@ public static BreakTextResult breakText(
} else if (whitespace == IdentValue.PRE) {
context.setEnd(context.getLast());
context.setWidth(Breaker.getTextWidthWithLetterSpacing(c, font, context.getCalculatedSubstring(), letterSpacing));
context.setNeedsNewLine(false);
}
}

Expand Down Expand Up @@ -208,8 +213,8 @@ public static BreakTextResult breakText(
break LOOP;

case CHAR_BREAKING_UNBREAKABLE:
if (totalWidth == 0 &&
avail == lineWidth) {
if ((totalWidth == 0 && avail == lineWidth) ||
forceOutput) {
// We are at the start of the line but could not fit a single character!
totalWidth += context.getWidth();
breakResult = BreakTextResult.CHAR_UNBREAKABLE_BUT_CONSUMED;
Expand All @@ -219,6 +224,7 @@ public static BreakTextResult breakText(
// FIXME: This is very dangerous and has led to infinite
// loops. Needs review.
context.setEnd(savedEnd);
context.setNeedsNewLine(true);
breakResult = BreakTextResult.DANGER_RECONSUME_CHAR_ON_NL;
break LOOP;
}
Expand All @@ -243,7 +249,8 @@ public static BreakTextResult breakText(
}
case WORD_BREAKING_UNBREAKABLE: {
if (context.getWidth() >= lineWidth ||
context.isFirstCharInLine()) {
context.isFirstCharInLine() ||
forceOutput) {
// If the word is too long to fit on a line by itself or
// if we are at the start of a line,
// retry in character breaking mode.
Expand Down Expand Up @@ -295,7 +302,7 @@ private static BreakTextResult toBreakTextResult(LineBreakResult res) {
case CHAR_BREAKING_NEED_NEW_LINE: // Fall-thru
case CHAR_BREAKING_UNBREAKABLE: // Fall-thru
default:
throw new RuntimeException(); // TODO: Log
throw new RuntimeException("PROGRAMMER ERROR: Unexpected LineBreakResult from word wrap");
}
}

Expand All @@ -320,12 +327,12 @@ private static LineBreakResult doBreakText(

String currentString = context.getStartSubstring();
FSTextBreaker lineIterator = STANDARD_LINE_BREAKER.getBreaker(currentString, c.getSharedContext());
FSTextBreaker charIterator = STANDARD_CHARACTER_BREAKER.getBreaker(currentString, c.getSharedContext());
FSTextBreaker charIterator = STANDARD_CHARACTER_BREAKER.getBreaker(currentString, c.getSharedContext());

return doBreakCharacters(currentString, lineIterator, charIterator, context, avail, letterSpacing, measurer);
}
}

/**
* Breaks at most one word (until the next word break) going character by character to see
* what will fit in.
Expand Down Expand Up @@ -393,11 +400,12 @@ static LineBreakResult doBreakCharacters(
graphicsLength > 0) {
// Exact fit..
boolean needNewLine = currentString.length() > left;

context.setNeedsNewLine(needNewLine);
context.setEnd(left + context.getStart());
context.setWidth(graphicsLength);

context.setUnbreakable(false);

if (left >= currentString.length()) {
return LineBreakResult.CHAR_BREAKING_FINISHED;
} else if (left >= nextWordBreak) {
Expand Down Expand Up @@ -430,6 +438,7 @@ static LineBreakResult doBreakCharacters(
context.setWidth(graphicsLength);
context.setEnd(nextCharBreak + context.getStart());
context.setEndsOnWordBreak(nextCharBreak == nextWordBreak);
context.setUnbreakable(false);

if (nextCharBreak >= currentString.length()) {
return LineBreakResult.CHAR_BREAKING_FINISHED;
Expand All @@ -448,8 +457,10 @@ static LineBreakResult doBreakCharacters(
context.setWidth(lastGoodGraphicsLength);
context.setEnd(lastGoodWrap + context.getStart());
context.setEndsOnWordBreak(lastGoodWrap == nextWordBreak);
context.setUnbreakable(false);

if (lastGoodWrap >= currentString.length()) {
context.setNeedsNewLine(false);
return LineBreakResult.CHAR_BREAKING_FINISHED;
} else if (lastGoodWrap >= nextWordBreak) {
return LineBreakResult.CHAR_BREAKING_FOUND_WORD_BREAK;
Expand All @@ -466,13 +477,15 @@ static LineBreakResult doBreakCharacters(
context.setEnd(end + context.getStart());
context.setEndsOnWordBreak(end == nextWordBreak);
context.setWidth(splitWidth);

context.setNeedsNewLine(end < currentString.length());

return LineBreakResult.CHAR_BREAKING_UNBREAKABLE;
} else {
// Empty string.
context.setEnd(context.getStart());
context.setWidth(0);
context.setNeedsNewLine(false);
context.setUnbreakable(false);

return LineBreakResult.CHAR_BREAKING_FINISHED;
}
Expand Down Expand Up @@ -588,6 +601,7 @@ static LineBreakResult doBreakTextWords(
if (current.graphicsLength <= avail) {
context.setWidth(current.graphicsLength);
context.setEnd(context.getMaster().length());
context.setNeedsNewLine(false);
// It all fit!
return LineBreakResult.WORD_BREAKING_FINISHED;
}
Expand Down
126 changes: 35 additions & 91 deletions openhtmltopdf-core/src/main/java/com/openhtmltopdf/layout/InlineBoxing.java
View file
Original file line number Diff line number Diff line change
Expand Up @@ -159,8 +159,6 @@ public static void layoutContent(LayoutContext c, BlockBox box, int initialY, in
}

boolean inCharBreakingMode = false;
int troublesomeStartPosition = -1;
int troublesomeAttemptCount = 0;

do {
lbContext.reset();
Expand Down Expand Up @@ -191,34 +189,24 @@ public static void layoutContent(LayoutContext c, BlockBox box, int initialY, in
needFirstLetter = false;
} else {
if (style.getWordWrap() != IdentValue.BREAK_WORD) {
StartInlineTextResult result = startInlineText(c, lbContext, inlineBox, space, current, fit, trimmedLeadingSpace, false);
StartInlineTextResult result = startInlineText(c, lbContext, inlineBox, space, current, fit, trimmedLeadingSpace, false, lbContext.possibleEndlessLoop());
if (result == StartInlineTextResult.RECONSUME_BELOW_FLOATS) {
lbContext.newLine();
continue;
}
} else {
StartInlineTextResult result = startInlineText(c, lbContext, inlineBox, space, current, fit, trimmedLeadingSpace, inCharBreakingMode);
StartInlineTextResult result = startInlineText(c, lbContext, inlineBox, space, current, fit, trimmedLeadingSpace, inCharBreakingMode, lbContext.possibleEndlessLoop());
inCharBreakingMode = lbContext.isFinishedInCharBreakingMode();

if (result == StartInlineTextResult.RECONSUME_BELOW_FLOATS) {
lbContext.newLine();
continue;
} else if (result == StartInlineTextResult.RECONSUME_UNBREAKABLE_ON_NEW_LINE) {
if (troublesomeStartPosition == lbContext.getStart()) {
troublesomeAttemptCount++;
} else {
troublesomeStartPosition = lbContext.getStart();
troublesomeAttemptCount = 1;
}

if (troublesomeAttemptCount > 5) {
XRLog.log(Level.SEVERE, LogMessageId.LogMessageId2Param.GENERAL_FATAL_INFINITE_LOOP_BUG_IN_LINE_BREAKING_ALGO,
lbContext.getStartSubstring(), lbContext.getEnd());
throw new RuntimeException("Infinite loop bug in break-word line breaking algorithm!");
}
}
}
} }
}

if (lbContext.isNeedsNewLine()) {
lbContext.newLine();

startNewInlineLine(c, box, breakAtLine, blockLayoutDirection, space, current, previous,
contentStart, openInlineBoxes, iBMap, minimumLineHeight, markerData, pendingFloats,
hasFirstLinePEs, pendingInlineLayers, lineOffset, inlineBox, lbContext);
Expand Down Expand Up @@ -402,26 +390,34 @@ private enum StartInlineTextResult {
* layout box.
* Otherwise, if there are floats and the current line is otherwise empty, moves below float and trys again.
* Otherwise, trys again on a new line.
* @return true if the line is finished, false if we must continue
*/
private static StartInlineTextResult startInlineText(
LayoutContext c, LineBreakContext lbContext, InlineBox inlineBox,
SpaceVariables space, StateVariables current, int fit,
boolean trimmedLeadingSpace, boolean tryToBreakAnywhere) {
LayoutContext c,
LineBreakContext lbContext,
InlineBox inlineBox,
SpaceVariables space,
StateVariables current,
int fit,
boolean trimmedLeadingSpace,
boolean tryToBreakAnywhere,
boolean forceOutput) {

lbContext.saveEnd();
CalculatedStyle style = inlineBox.getStyle();

// Layout the text into the remaining width on this line. Will only go to the end of the line (at most)
// and will produce one InlineText object.
InlineText inlineText = layoutText(
c, style, space.remainingWidth - fit, lbContext, false, inlineBox.getTextDirection(), tryToBreakAnywhere, space.maxAvailableWidth - fit);
c, style, space.remainingWidth - fit, lbContext, false, inlineBox.getTextDirection(), tryToBreakAnywhere, space.maxAvailableWidth - fit, forceOutput);

if (style.hasLetterSpacing()) {
inlineText.setLetterSpacing(style.getFloatPropertyProportionalWidth(CSSName.LETTER_SPACING, 0, c));
}

if (lbContext.isUnbreakable() && !current.line.isContainsContent()) {

if (lbContext.isUnbreakable() &&
!current.line.isContainsContent() &&
!forceOutput) {

int delta = c.getBlockFormattingContext().getNextLineBoxDelta(c, current.line, space.maxAvailableWidth);

if (delta > 0) {
Expand All @@ -444,7 +440,13 @@ private static StartInlineTextResult startInlineText(
if (!lbContext.isUnbreakable() ||
(lbContext.isUnbreakable() &&
!current.line.isContainsContent() &&
lbContext.getEnd() > lbContext.getStart())) {
lbContext.getEnd() > lbContext.getStart()) ||
forceOutput) {

if (forceOutput) {
XRLog.log(Level.SEVERE, LogMessageId.LogMessageId1Param.GENERAL_FORCED_OUTPUT_TO_AVOID_INFINITE_LOOP, lbContext.getCalculatedSubstring());
}

// We can use the inline text by adding it to the current inline layout box.
// We also mark the text as consumed by the line break context and reduce the width
// we have remaining on this line.
Expand Down Expand Up @@ -556,8 +558,8 @@ private static InlineLayoutBox addFirstLetterBox(LayoutContext c, LineBox curren
currentIB.addInlineChild(c, iB);
current.setContainsContent(true);

InlineText text = layoutText(c, iB.getStyle(), remainingWidth, lbContext, true, textDirection, true, maxAvailableWidth);
InlineText text = layoutText(c, iB.getStyle(), remainingWidth, lbContext, true, textDirection, true, maxAvailableWidth, false);

if (iB.getStyle().hasLetterSpacing()) {
text.setLetterSpacing(iB.getStyle().getFloatPropertyProportionalWidth(CSSName.LETTER_SPACING, 0, c));
}
Expand Down Expand Up @@ -1109,7 +1111,8 @@ private static InlineText layoutText(
boolean needFirstLetter,
byte textDirection,
boolean tryToBreakAnywhere,
int lineWidth) {
int lineWidth,
boolean forceOutput) {

InlineText result = new InlineText();
String masterText = lbContext.getMaster();
Expand All @@ -1120,8 +1123,8 @@ private static InlineText layoutText(
Breaker.breakFirstLetter(c, lbContext, remainingWidth, style);
} else {
BreakTextResult breakResult =
Breaker.breakText(c, lbContext, remainingWidth, style, tryToBreakAnywhere, lineWidth);
checkBreakResult(breakResult, lbContext, tryToBreakAnywhere);
Breaker.breakText(c, lbContext, remainingWidth, style, tryToBreakAnywhere, lineWidth, forceOutput);
lbContext.checkConsistency(breakResult);
}

result.setMasterText(masterText);
Expand All @@ -1133,65 +1136,6 @@ private static InlineText layoutText(
return result;
}

private static void checkBreakResult(
BreakTextResult breakResult,
LineBreakContext lbContext,
boolean tryToBreakAnywhere) {

switch (breakResult) {
case CONTINUE_CHAR_BREAKING_ON_NL:
if (lbContext.getStart() >= lbContext.getEnd() ||
!lbContext.isNeedsNewLine()) {
fail(breakResult, lbContext);
}
break;
case CONTINUE_WORD_BREAKING_ON_NL:
if (lbContext.getStart() >= lbContext.getEnd() ||
lbContext.isUnbreakable() ||
!lbContext.isNeedsNewLine()) {
fail(breakResult, lbContext);
}
break;
case DANGER_RECONSUME_CHAR_ON_NL:
if (lbContext.getStart() > lbContext.getEnd()) {
fail(breakResult, lbContext);
}
break;
case DANGER_RECONSUME_WORD_ON_NL:
if (lbContext.getStart() > lbContext.getEnd()) {
fail(breakResult, lbContext);
}
break;
case FINISHED:
if (!lbContext.isFinished() ||
lbContext.getStart() >= lbContext.getEnd() ||
lbContext.isUnbreakable() ||
lbContext.isNeedsNewLine()) {
fail(breakResult, lbContext);
}
break;
case WORD_UNBREAKABLE_BUT_CONSUMED:
if (!lbContext.isUnbreakable() ||
lbContext.getStart() >= lbContext.getEnd()) {
fail(breakResult, lbContext);
}
break;
case CHAR_UNBREAKABLE_BUT_CONSUMED:
if (!lbContext.isUnbreakable() ||
lbContext.getStart() >= lbContext.getEnd()) {
fail(breakResult, lbContext);
}
break;
}
}

private static void fail(
BreakTextResult breakResult,
LineBreakContext lbContext) {
// TODO: Log
throw new RuntimeException();
}

private static int processOutOfFlowContent(
LayoutContext c, LineBox current, BlockBox block,
int available, List<FloatLayoutResult> pendingFloats) {
Expand Down
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