fractorium/Source/Fractorium/csshighlighter.cpp

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#include "FractoriumPch.h"
#include "csshighlighter.h"

/// <summary>
/// The code in this file did not originate in Fractorium.
/// It was taken either in whole or in part from the source code
/// of Qt Creator. Their license applies.
/// </summary>

CssHighlighter::CssHighlighter(QTextDocument* document)
	: QSyntaxHighlighter(document)
{
}

void CssHighlighter::highlightBlock(const QString& text)
{
	enum Token { ALNUM, LBRACE, RBRACE, COLON, SEMICOLON, COMMA, QUOTE, SLASH, STAR };
	static const int transitions[10][9] =
	{
		{ Selector, Property, Selector, Pseudo,    Property, Selector, Quote, MaybeComment, Selector }, // Selector
		{ Property, Property, Selector, Value,     Property, Property, Quote, MaybeComment, Property }, // Property
		{ Value,    Property, Selector, Value,     Property, Value,    Quote, MaybeComment, Value }, // Value
		{ Pseudo1, Property, Selector, Pseudo2,    Selector, Selector, Quote, MaybeComment, Pseudo }, // Pseudo
		{ Pseudo1, Property, Selector, Pseudo,    Selector, Selector, Quote, MaybeComment, Pseudo1 }, // Pseudo1
		{ Pseudo2, Property, Selector, Pseudo,    Selector, Selector, Quote, MaybeComment, Pseudo2 }, // Pseudo2
		{ Quote,    Quote,    Quote,    Quote,     Quote,    Quote,   -1, Quote, Quote }, // Quote
		{ -1, -1, -1, -1, -1, -1, -1, -1, Comment }, // MaybeComment
		{ Comment, Comment, Comment, Comment, Comment, Comment, Comment, Comment, MaybeCommentEnd }, // Comment
		{ Comment, Comment, Comment, Comment, Comment, Comment, Comment, -1, MaybeCommentEnd } // MaybeCommentEnd
	};
	int lastIndex = 0;
	bool lastWasSlash = false;
	int state = previousBlockState(), save_state = 0;

	if (state == -1)
	{
		// As long as the text is empty, leave the state undetermined
		if (text.isEmpty())
		{
			setCurrentBlockState(-1);
			return;
		}

		// The initial state is based on the precense of a : and the absense of a {.
		// This is because Qt style sheets support both a full stylesheet as well as
		// an inline form with just properties.
		state = save_state = (text.indexOf(QLatin1Char(':')) > -1 &&
							  text.indexOf(QLatin1Char('{')) == -1) ? Property : Selector;
	}
	else
	{
		save_state = state >> 16;
		state &= 0x00ff;
	}

	if (state == MaybeCommentEnd)
	{
		state = Comment;
	}
	else if (state == MaybeComment)
	{
		state = save_state;
	}

	for (int i = 0; i < text.length(); i++)
	{
		int token = ALNUM;
		const QChar c = text.at(i);
		const char a = c.toLatin1();

		if (state == Quote)
		{
			if (a == '\\')
			{
				lastWasSlash = true;
			}
			else
			{
				if (a == '\"' && !lastWasSlash)
				{
					token = QUOTE;
				}

				lastWasSlash = false;
			}
		}
		else
		{
			switch (a)
			{
				case '{': token = LBRACE; break;

				case '}': token = RBRACE; break;

				case ':': token = COLON; break;

				case ';': token = SEMICOLON; break;

				case ',': token = COMMA; break;

				case '\"': token = QUOTE; break;

				case '/': token = SLASH; break;

				case '*': token = STAR; break;

				default: break;
			}
		}

		const auto new_state = transitions[state][token];

		if (new_state != state)
		{
			const auto include_token = new_state == MaybeCommentEnd || (state == MaybeCommentEnd && new_state != Comment)
									   || state == Quote;
			highlight(text, lastIndex, i - lastIndex + (include_token ? 1 : 0), state);

			if (new_state == Comment)
			{
				lastIndex = i - 1; // include the slash and star
			}
			else
			{
				lastIndex = i + ((token == ALNUM || new_state == Quote) ? 0 : 1);
			}
		}

		if (new_state == -1)
		{
			state = save_state;
		}
		else if (state <= Pseudo2)
		{
			save_state = state;
			state = new_state;
		}
		else
		{
			state = new_state;
		}
	}

	highlight(text, lastIndex, text.length() - lastIndex, state);
	setCurrentBlockState(state + (save_state << 16));
}

void CssHighlighter::highlight(const QString& text, int start, int length, int state)
{
	if (start >= text.length() || length <= 0)
		return;

	QTextCharFormat format;

	switch (state)
	{
		case Selector:
			setFormat(start, length, QColor::fromRgb(43, 145, 175));//Teal, like the Visual Studio default for classes in C++ and C#.
			break;

		case Property:
			setFormat(start, length, Qt::darkBlue);
			break;

		case Value:
			setFormat(start, length, Qt::black);
			break;

		case Pseudo1:
			setFormat(start, length, Qt::darkRed);
			break;

		case Pseudo2:
			setFormat(start, length, Qt::black);
			break;

		case Quote:
			setFormat(start, length, Qt::darkMagenta);
			break;

		case Comment:
		case MaybeCommentEnd:
			format.setForeground(Qt::darkGreen);
			setFormat(start, length, format);
			break;

		default:
			break;
	}
}