1 files changed, 95 insertions, 0 deletions
diff --git a/src/corelib/kernel/qcore_mac.cpp b/src/corelib/kernel/qcore_mac.cpp
index bfb3b2ff07..b5df0db232 100644
--- a/src/corelib/kernel/qcore_mac.cpp
+++ b/src/corelib/kernel/qcore_mac.cpp
@@ -39,6 +39,9 @@
 
 #include <private/qcore_mac_p.h>
 #include <new>
+
+#include "qhash.h"
+#include "qpair.h"
 #include "qvarlengtharray.h"
 
 QT_BEGIN_NAMESPACE
@@ -57,4 +60,96 @@ QCFString::operator CFStringRef() const
     return value;
 }
 
+// --------------------------------------------------------------------------
+
+#if defined(QT_USE_APPLE_UNIFIED_LOGGING)
+
+bool AppleUnifiedLogger::messageHandler(QtMsgType msgType, const QMessageLogContext &context,
+                                        const QString &message, const QString &optionalSubsystem)
+{
+    QString subsystem = optionalSubsystem;
+    if (subsystem.isNull()) {
+        static QString bundleIdentifier = []() {
+            if (CFBundleRef bundle = CFBundleGetMainBundle()) {
+                if (CFStringRef identifier = CFBundleGetIdentifier(bundle))
+                    return QString::fromCFString(identifier);
+            }
+            return QString();
+        }();
+        subsystem = bundleIdentifier;
+    }
+
+    const bool isDefault = !context.category || !strcmp(context.category, "default");
+    os_log_t log = isDefault ? OS_LOG_DEFAULT :
+        cachedLog(subsystem, QString::fromLatin1(context.category));
+    os_log_type_t logType = logTypeForMessageType(msgType);
+
+    if (!os_log_type_enabled(log, logType))
+        return false;
+
+    // Logging best practices says we should not include symbolication
+    // information or source file line numbers in messages, as the system
+    // will automatically captures this information. In our case, what
+    // the system captures is the call to os_log_with_type below, which
+    // isn't really useful, but we still don't want to include the context's
+    // info, as that would clutter the logging output. See rdar://35958308.
+
+    // The format must be a string constant, so we can't pass on the
+    // message. This means we won't be able to take advantage of the
+    // unified logging's custom format specifiers such as %{BOOL}d.
+    // We use the 'public' format specifier to prevent the logging
+    // system from redacting our log message.
+    os_log_with_type(log, logType, "%{public}s", qPrintable(message));
+
+    // When running under Xcode or LLDB, one or more of these variables will
+    // be set, which triggers libsystem_trace.dyld to log messages to stderr
+    // as well, via_os_log_impl_mirror_to_stderr. Un-setting these variables
+    // is not an option, as that would silence normal NSLog or os_log calls,
+    // so instead we skip our own stderr output. See rdar://36919139.
+    static bool mirroredToStderr = qEnvironmentVariableIsSet("OS_ACTIVITY_DT_MODE")
+                                 || qEnvironmentVariableIsSet("ACTIVITY_LOG_STDERR")
+                                 || qEnvironmentVariableIsSet("CFLOG_FORCE_STDERR");
+    return mirroredToStderr;
+}
+
+os_log_type_t AppleUnifiedLogger::logTypeForMessageType(QtMsgType msgType)
+{
+    switch (msgType) {
+    case QtDebugMsg: return OS_LOG_TYPE_DEBUG;
+    case QtInfoMsg: return OS_LOG_TYPE_INFO;
+    case QtWarningMsg: return OS_LOG_TYPE_DEFAULT;
+    case QtCriticalMsg: return OS_LOG_TYPE_ERROR;
+    case QtFatalMsg: return OS_LOG_TYPE_FAULT;
+    }
+
+    return OS_LOG_TYPE_DEFAULT;
+}
+
+os_log_t AppleUnifiedLogger::cachedLog(const QString &subsystem, const QString &category)
+{
+    static QBasicMutex mutex;
+    QMutexLocker locker(&mutex);
+
+    static QHash<QPair<QString, QString>, os_log_t> logs;
+    const auto cacheKey = qMakePair(subsystem, category);
+    os_log_t log = logs.value(cacheKey);
+
+    if (!log) {
+        log = os_log_create(subsystem.toLatin1().constData(),
+            category.toLatin1().constData());
+        logs.insert(cacheKey, log);
+
+        // Technically we should release the os_log_t resource when done
+        // with it, but since we don't know when a category is disabled
+        // we keep all cached os_log_t instances until shutdown, where
+        // the OS will clean them up for us.
+    }
+
+    return log;
+}
+
+#endif // QT_USE_APPLE_UNIFIED_LOGGING
+
+// --------------------------------------------------------------------------
+
 QT_END_NAMESPACE