libcamera: base: log: Fix LogCategory creation issues

Each declaration of a LogCategory will create a new LogCategory, and
will be stored in an unordered_set Logger::categories_. This means that
when a plugin .so is unloaded and loaded, as happens when destructing
and creating a CamereManager, we'll get duplicate categories.

The Logger::registerCategory docs say "Log categories must have unique
names. If a category with the same name already exists this function
performs no operation.". The code does not comply with this.

We solve the issue with two changes:

Change the unordered_set to a vector for simplicity, as there's no need
for an unordered_set.

Instead of using the LogCategory constructor to create new categories in
_LOG_CATEGORY() macro, use a factory method. The factory method will
return either an existing LogCategory if one exists with the given name,
or a newly created one.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 4 insertions, 2 deletions

diff --git a/include/libcamera/base/log.h b/include/libcamera/base/log.h
index 8b462767..dcaacbe0 100644
--- a/include/libcamera/base/log.h
+++ b/include/libcamera/base/log.h
@@ -29,7 +29,7 @@ enum LogSeverity {
 class LogCategory
 {
 public:
-	explicit LogCategory(const char *name);
+	static LogCategory *create(const char *name);
 
 	const std::string &name() const { return name_; }
 	LogSeverity severity() const { return severity_; }
@@ -38,6 +38,8 @@ public:
 	static const LogCategory &defaultCategory();
 
 private:
+	explicit LogCategory(const char *name);
+
 	const std::string name_;
 	LogSeverity severity_;
 };
@@ -49,7 +51,7 @@ extern const LogCategory &_LOG_CATEGORY(name)();
 const LogCategory &_LOG_CATEGORY(name)()				\
 {									\
 	/* The instance will be deleted by the Logger destructor. */	\
-	static LogCategory *category = new LogCategory(#name);		\
+	static LogCategory *category = LogCategory::create(#name);	\
 	return *category;						\
 }