README.md

C++ --> WASM particles

Setup

Our C++ code is built by Bazel. You will need to install Bazel, and use it to build and run the wasm code/tests (everything under src/wasm/).

1. Installing Bazel: Follow project install instructions.

Build

See here for a working example.

• Add a BUILD file in the relevant directory
• Generate a C++ header file from your particle spec using the arcs_cc_schema build rule:

  arcs_cc_schema(
      # Name of the BUILD rule (tell Bazel to build this schema using this name).
      name = "example_schema",
      # Input source.
      src = "example.arcs",
      # Optional output filename.
      out = "example.h",
  )
  

• Write your C++ particle(s)
  • Include the Arcs C++ header: #include "src/wasm/cpp/arcs.h".
  • Include your generated schema header(s): #include "particles/Native/Wasm/example.h".
  • Particles inherit from arcs::Particle and use arcs::Singleton and arcs::Collection
• Add a wasm_cc_binary build rule for your C++ particle(s) to your BUILD file:

  cc_wasm_binary(
      # Name of the BUILD rule (tell Bazel to build this particle using this name).
      name = "example_particle",
      # Input C++ particle source files to compile.
      srcs = ["example.cc"],
      # Input C++ header files (example.h was generated by the example_schema rule above).
      hdrs = ["example.h"],
      # Other C++ dependencies this binary depends on (just the Arcs library).
      deps = ["//src/wasm/cpp:arcs"],
  )
  

• Build your particle using Bazel: ./tools/bazelisk build //particles/Native/Wasm:example_particle.

Execute

• tools/sigh devServer
• Visit localhost:8786/shells/dev-shell/?m=https://$arcs/particles/Native/Wasm/example.arcs (TODO(csilvestrini): update this path)

Test

./tools/bazelisk test //src/wasm/tests:wasm-api-test