Cwtch Autobindings

Automatically generate Cwtch C-Bindings from a high-level specification.

Note for the Flutter-based Cwtch UI Application see: https://git.openprivacy.ca/cwtch.im/cwtch-ui

Building

go mod download
go run generate/generate_bindings.go
make linux  // alternatively windows, android, macos

NOTE: Autobindings currently depends on an unreleased version of Cwtch (cwtch.im/cwtch v0.18.10-0.20230221235514-49e0d849fa3e).

Experiments

Autobindings allow for comile time selection of experiments. Default selections for each target platform are supplied in Makefile but can be overridden with:

env EXPERIMENTS="serverExperiment otherExperiment" make android

Spec File Format

The current Cwtch Bindings Specification is defined in spec

Supported function prototypes:

• app <Function Name> <Args> - an application-level function, called on global Application
• profile <Function Name> <Args> - a profile-level function, takes profile as an implicit first argument
• json(profile) <Function Name> <Args> - a profile-level function, takes profile as an implicit first argument and returns a json blob that must be freed by the calling library (see MEMORY)
• @profile-experiment <Function Name> <Experiment> <Args>- an experimental profile-level function, takes profile as an implicit first argument, experiment must implement cwtch Functionality interface
• @(json)profile-experiment <Function Name> <Experiment> <Args> - am experimental profile-level function, takes profile as an implicit first argument and returns a json blob that must be freed by the calling (see MEMORY) library, , experiment must implement cwtch Functionality interface

Supported argument prototypes:

• profile - a cwtch profile identifier
• conversation - a cwtch conversation identifier
• message - a cwtch message identifier
• int:<name> - a generic integer argument (with optional name)
• bool:<name> - a generic boolean argument (with optional name)
• string:<name> - a generic string argument (with optional name)

All arguments must be defined in the order they are specified by the underlying Cwtch library function.

Other directives:

• import <go pkg> - includes an additional go importin the compiled lib.go (needed for experiments)
• Functions that start with Enhanced are automatically stripped of that prefix for their binding names e.g. EnhancedGetMessage generated a binding c_GetMessage - for certain functions Cwtch has two potential calling options <Function> and Enhanced<Function>. "Enhanced" in this case means that the response is optimised for calling by a user-facing application by e.g. directly making a number of calls under the hood and returning a json blob of the results.

Using

General Environment Variables

• LOG_FILE if defined will mean all go logging will go to a file instead of stdout
• LOG_LEVEL if set to debug will cause debug logging to be included in log output
• CWTCH_PROFILE if set to 1 will cause a memory profile to be written to mem.prof and all active goroutines written to stdout when DebugInfo() is called.
• CWTCH_TAILS if set to true will override the Tor configuration to allow Cwtch to work in a Tail-like environment.

Linux Desktop:

• LD_LIBRARY_PATH set to point to libCwtch.so
• or drop a symlink into /usr/lib

Android

• copy cwtch.aar into flutter_app/android/cwtch

Windows

• copy libCwtch.dll into the directory of the .exe using it

MacOS

• copy libCwtch.x64.dylib and libCwtch.arm.dylib into the directory you are executing from

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