core/log: add read-log --filter

src/core/logging_qtprivate.cpp

@@ -0,0 +1,159 @@
+// The logging rule parser from qloggingregistry_p.h and qloggingregistry.cpp.
+
+// Was unable to properly link the functions when directly using the headers (which we depend
+// on anyway), so below is a slightly stripped down copy. Making the originals link would
+// be preferable.
+
+#include <utility>
+
+#include <qbytearrayview.h>
+#include <qchar.h>
+#include <qflags.h>
+#include <qlist.h>
+#include <qlogging.h>
+#include <qloggingcategory.h>
+#include <qstringtokenizer.h>
+#include <qstringview.h>
+#include <qtypes.h>
+
+namespace qs::log {
+Q_DECLARE_LOGGING_CATEGORY(logLogging);
+
+namespace qt_logging_registry {
+
+class QLoggingRule {
+public:
+	QLoggingRule();
+	QLoggingRule(QStringView pattern, bool enabled);
+	[[nodiscard]] int pass(QLatin1StringView categoryName, QtMsgType type) const;
+
+	enum PatternFlag {
+		FullText = 0x1,
+		LeftFilter = 0x2,
+		RightFilter = 0x4,
+		MidFilter = LeftFilter | RightFilter
+	};
+	Q_DECLARE_FLAGS(PatternFlags, PatternFlag)
+
+	QString category;
+	int messageType;
+	PatternFlags flags;
+	bool enabled;
+
+private:
+	void parse(QStringView pattern);
+};
+
+class QLoggingSettingsParser {
+public:
+	void setContent(QStringView content);
+
+	[[nodiscard]] QList<QLoggingRule> rules() const { return this->mRules; }
+
+private:
+	void parseNextLine(QStringView line);
+
+private:
+	QList<QLoggingRule> mRules;
+};
+
+void QLoggingSettingsParser::setContent(QStringView content) {
+	this->mRules.clear();
+	for (auto line: qTokenize(content, u';')) this->parseNextLine(line);
+}
+
+void QLoggingSettingsParser::parseNextLine(QStringView line) {
+	// Remove whitespace at start and end of line:
+	line = line.trimmed();
+
+	const qsizetype equalPos = line.indexOf(u'=');
+	if (equalPos != -1) {
+		if (line.lastIndexOf(u'=') == equalPos) {
+			const auto key = line.left(equalPos).trimmed();
+			const QStringView pattern = key;
+			const auto valueStr = line.mid(equalPos + 1).trimmed();
+			int value = -1;
+			if (valueStr == QString("true")) value = 1;
+			else if (valueStr == QString("false")) value = 0;
+			QLoggingRule rule(pattern, (value == 1));
+			if (rule.flags != 0 && (value != -1)) this->mRules.append(std::move(rule));
+			else
+				qCWarning(logLogging, "Ignoring malformed logging rule: '%s'", line.toUtf8().constData());
+		} else {
+			qCWarning(logLogging, "Ignoring malformed logging rule: '%s'", line.toUtf8().constData());
+		}
+	}
+}
+
+QLoggingRule::QLoggingRule(QStringView pattern, bool enabled): messageType(-1), enabled(enabled) {
+	this->parse(pattern);
+}
+
+void QLoggingRule::parse(QStringView pattern) {
+	QStringView p;
+
+	// strip trailing ".messagetype"
+	if (pattern.endsWith(QString(".debug"))) {
+		p = pattern.chopped(6); // strlen(".debug")
+		this->messageType = QtDebugMsg;
+	} else if (pattern.endsWith(QString(".info"))) {
+		p = pattern.chopped(5); // strlen(".info")
+		this->messageType = QtInfoMsg;
+	} else if (pattern.endsWith(QString(".warning"))) {
+		p = pattern.chopped(8); // strlen(".warning")
+		this->messageType = QtWarningMsg;
+	} else if (pattern.endsWith(QString(".critical"))) {
+		p = pattern.chopped(9); // strlen(".critical")
+		this->messageType = QtCriticalMsg;
+	} else {
+		p = pattern;
+	}
+
+	const QChar asterisk = u'*';
+	if (!p.contains(asterisk)) {
+		this->flags = FullText;
+	} else {
+		if (p.endsWith(asterisk)) {
+			this->flags |= LeftFilter;
+			p = p.chopped(1);
+		}
+		if (p.startsWith(asterisk)) {
+			this->flags |= RightFilter;
+			p = p.mid(1);
+		}
+		if (p.contains(asterisk)) // '*' only supported at start/end
+			this->flags = PatternFlags();
+	}
+
+	this->category = p.toString();
+}
+
+int QLoggingRule::pass(QLatin1StringView cat, QtMsgType msgType) const {
+	// check message type
+	if (this->messageType > -1 && this->messageType != msgType) return 0;
+
+	if (this->flags == FullText) {
+		// full match
+		if (this->category == cat) return (this->enabled ? 1 : -1);
+		else return 0;
+	}
+
+	const qsizetype idx = cat.indexOf(this->category);
+	if (idx >= 0) {
+		if (this->flags == MidFilter) {
+			// matches somewhere
+			return (this->enabled ? 1 : -1);
+		} else if (this->flags == LeftFilter) {
+			// matches left
+			if (idx == 0) return (this->enabled ? 1 : -1);
+		} else if (this->flags == RightFilter) {
+			// matches right
+			if (idx == (cat.size() - this->category.size())) return (this->enabled ? 1 : -1);
+		}
+	}
+	return 0;
+}
+
+} // namespace qt_logging_registry
+
+} // namespace qs::log