3.0 KiB
LogManagerProvider
The LogManagerProvider class supplies instances of ILogManager. It is used by the static Initialize() methods in LogManagerBase<> to set the private pointer to its singleton implementation (and this includes the default LogManager class derived from LogManagerBase<>). It can be used without LogManagerBase<> to get an instance pointer directly.
ILogConfiguration host and name
LogManagerProvider uses two parameters from ILogConfiguration for its method CreateLogManager(ILogConfiguration &, status_t), the host and name parameters (both strings). The name parameter is accessed as config[CFG_STR_FACTORY_NAME]. The host parameter is at config[CFG_MAP_FACTORY_CONFIG][CFG_STR_FACTORY_HOST]. These combine to determine which log manager instance you get when you call CreateLogManager.
Exclusive Log Manager
When the host value is empty, you will get an exclusive instance. Which instance you get is determined by name. CreateLogManager will return the same instance for a given name whenever it is called with an empty host. The default configuration does not define name, so all instances of LogManagerBase<> will by default be the same log manager (with a name of "").
Shared Log Manager
When the host value is not empty, you will get a shared instance. host may either be "*" (any host, the wildcard host) or an arbitrary host name.
Any Host
When host is "*", if there are already any shared instances, CreateLogManager returns the first shared instance in its map (and this name is added to that instances list of names).
Otherwise, CreateLogManager creates a new shared instance for the wildcard "*" host and returns it.
Specific Host
When host is not a wildcard "*", and a shared instance for that host exists, CreateLogManager returns it. Otherwise, if there is a log manager for the wildcard "*" host, CreateLogManager repurposes it to be the instance for this named host and the existing wildcard hosts, and returns that. If neither of those conditions is true, we don't need to repurpose a wildcard instance and we don't have a specified-host instance, so CreateLogManager creates the new instance and returns it.
Exclusive and Shared
Exclusive log managers don't have a host identifier. No shared log manager will ever get a pointer to an exclusive manager instance. All exclusive log managers with the same name (including the default blank name) are the same log manager (so they are, so to speak, shared). Shared log managers are differentiated by host rather than name, and can either be wildcard (use any log manager) or specific-host. One shared specific-host log manager serves all the wildcard log manager requests. In the absence of a shared specific-host log manager, all wildcard-host log managers share one instance (which will be converted to specific-host as soon as the first shared specific-host manager is requested).