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Fixes for findVersionDirectivePosition()

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The old code was wrong as it used QString::fromUtf8() to convert the
char * array to a QString. This could lead to wrong positions when trying
to find the #version directive, as any valid utf8 sequence in a comment
before could have lead to wrong offsets compared to the 8 bit data.

Fix this and optimize the code at the same time to avoid creating a copy
of the data and using QRegularExpression.

Also fixes building Qt with -no-feature-regularexpression

Change-Id: I2d84875ef59b3a0fb4d8b069bf56f4372c57ccdc
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>
This commit is contained in:
Lars Knoll 2016-10-27 09:42:56 +02:00
parent 01c3565d3e
commit c442244907
1 changed files with 47 additions and 36 deletions
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83
src/gui/opengl/qopenglshaderprogram.cpp
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@ -432,73 +432,84 @@ static QVersionDirectivePosition findVersionDirectivePosition(const char *source
{
Q_ASSERT(source);
QString working = QString::fromUtf8(source);
// According to the GLSL spec the #version directive must not be
// preceded by anything but whitespace and comments.
// In order to not get confused by #version directives within a
// multiline comment, we need to run a minimal preprocessor first.
// multiline comment, we need to do some minimal comment parsing
// while searching for the directive.
enum {
Normal,
StartOfLine,
PreprocessorDirective,
CommentStarting,
MultiLineComment,
SingleLineComment,
CommentEnding
} state = Normal;
} state = StartOfLine;
for (QChar *c = working.begin(); c != working.end(); ++c) {
const char *c = source;
while (*c) {
switch (state) {
case Normal:
if (*c == QLatin1Char('/'))
case PreprocessorDirective:
if (*c == ' ' || *c == '\t')
break;
if (!strncmp(c, "version", strlen("version"))) {
// Found version directive
c += strlen("version");
while (*c && *c != '\n')
++c;
int splitPosition = c - source + 1;
int linePosition = int(std::count(source, c, '\n')) + 1;
return QVersionDirectivePosition(splitPosition, linePosition);
} else if (*c == '/')
state = CommentStarting;
else if (*c == '\n')
state = StartOfLine;
else
state = Normal;
break;
case StartOfLine:
if (*c == ' ' || *c == '\t')
break;
else if (*c == '#') {
state = PreprocessorDirective;
break;
}
state = Normal;
// fall through
case Normal:
if (*c == '/')
state = CommentStarting;
else if (*c == '\n')
state = StartOfLine;
break;
case CommentStarting:
if (*c == QLatin1Char('*'))
if (*c == '*')
state = MultiLineComment;
else if (*c == QLatin1Char('/'))
else if (*c == '/')
state = SingleLineComment;
else
state = Normal;
break;
case MultiLineComment:
if (*c == QLatin1Char('*'))
if (*c == '*')
state = CommentEnding;
else if (*c == QLatin1Char('#'))
*c = QLatin1Char('_');
break;
case SingleLineComment:
if (*c == QLatin1Char('\n'))
if (*c == '\n')
state = Normal;
else if (*c == QLatin1Char('#'))
*c = QLatin1Char('_');
break;
case CommentEnding:
if (*c == QLatin1Char('/')) {
if (*c == '/')
state = Normal;
} else {
if (*c == QLatin1Char('#'))
*c = QLatin1Char('_');
if (*c != QLatin1Char('*'))
state = MultiLineComment;
}
else if (*c != QLatin1Char('*'))
state = MultiLineComment;
break;
}
++c;
}
// Search for #version directive
int splitPosition = 0;
int linePosition = 1;
static const QRegularExpression pattern(QStringLiteral("^\\s*#\\s*version.*(\\n)?"),
QRegularExpression::MultilineOption
| QRegularExpression::OptimizeOnFirstUsageOption);
QRegularExpressionMatch match = pattern.match(working);
if (match.hasMatch()) {
splitPosition = match.capturedEnd();
linePosition += int(std::count(working.begin(), working.begin() + splitPosition, QLatin1Char('\n')));
}
return QVersionDirectivePosition(splitPosition, linePosition);
return QVersionDirectivePosition(0, 1);
}
/*!