ProceduralStructGenerator's genRecord and genEnum were package-private, and only extractClassStruct was made public.
However, this package private visibility rendered them unable to be used by the rest of wpilib(and advanced users).
Here, ProceduralStructGenerator is split into 2 classes: StructGenerator(which generates structs) and StructFetcher(the new namespace for extractClassStruct). In addition, genRecord and genEnum have been made public methods.
Due to how submessages are encoded (with a length prefix), nanopb currently does the encoding twice. It encodes once to get the length to write, then writes the length, then reencodes the entire message a 2nd time.
This results in a requirement that each encode always encodes the same. Generally, this is fine, but it'd be nice to not make this a requirement.
The double encode also requires going through the entire set of fields again, which has the possibility to be slow.
Instead of doing this, write to a temporary SmallVector. Then we can just encode the length of that buffer, and do a memcpy into primary stream. Theoretically in most cases, this should be much faster.
The Google C++ protobuf implementation has issues with dynamic linkage across DLL boundaries because it uses global variables. It also has a compile-time dependency because the protoc version must exactly match the libprotobuf version. Using nanopb with a customized generator fixes both of these issues.
Co-authored-by: Gold856 <117957790+Gold856@users.noreply.github.com>
This refactors Alert in both c++ and java to fix the issues with the current c++ implementation and improve performance.
Currently, constructing an Alert adds it to a list of Alerts with the same group and type. Activating an alert sets a flag on the alert. When the SendableAlerts is polled (GetStrings), the entire list is iterated over, filtered, and the filtered list is sorted by timestamp. This leads to a worst case O(m + nlog(n)) time complexity for GetStrings, where m and n are the count of total constructed alerts active alerts respectively. It also allocates intermediate data structures to hold the active alert strings for sorting.
This changes the implementation to improve the performance of GetStrings, by shifting the sorting overhead to Alert.Set
Constructing the Alert only initializes the alert's initial state, and initializes the SendableAlerts for the group if it is not already initialized.
Activating or deactivating an alert sets an internal flag for state tracking, and inserts or removes a structure containing the timestamp and text into a self-sorting data structure (std::set, TreeSet) containing other active alerts with the same group and type. (worst case O(log(n))
Now, SendableAlerts.GetStrings only has to iterate over the structure and copy the strings to the returned array. (amortized O(n))
This also fixes the c++ implementation by removing the need for SendableAlerts to directly access the Alert.
This also adds a helper method to SendableRegistry to force initialization of the instance to prevent static initialization ordering issues.
After a struct-type field descriptor had offsets calculated more than once, IsBitField would return true, causing the second call to CalculateOffsets to calculate incorrect offsets.
As string_view operations on std::map<std::string> won't be integrated
until C++26, placeholder implementations are used which are less efficient
in a couple of situations (e.g. insert with hint).
