From be80c57b3c65ab8dd074e8a1487b8830843a7ac9 Mon Sep 17 00:00:00 2001 From: Divy Srivastava Date: Fri, 7 Oct 2022 00:26:36 -0700 Subject: chore(napi): Add README explainer for cli/napi_sym and cli/napi (#16187) --- cli/napi_sym/README.md | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 cli/napi_sym/README.md (limited to 'cli/napi_sym') diff --git a/cli/napi_sym/README.md b/cli/napi_sym/README.md new file mode 100644 index 000000000..80bb2be0f --- /dev/null +++ b/cli/napi_sym/README.md @@ -0,0 +1,34 @@ +# napi_sym + +A proc_macro for Deno's Node-API implementation. It does the following things: + +- Marks the symbol as `#[no_mangle]` and rewrites it as `pub extern "C" $name`. +- Asserts that the function symbol is present in + [`symbol_exports.json`](./symbol_exports.json). +- Maps `deno_napi::Result` to raw `napi_result`. + +```rust +use deno_napi::{napi_value, Env, Error, Result}; + +#[napi_sym::napi_sym] +fn napi_get_boolean( + env: *mut Env, + value: bool, + result: *mut napi_value, +) -> Result { + let _env: &mut Env = env.as_mut().ok_or(Error::InvalidArg)?; + // *result = ... + Ok(()) +} +``` + +### `symbol_exports.json` + +A file containing the symbols that need to be put into the exectable's dynamic +symbol table at link-time. + +This is done using `/DEF:` on Windows, `-exported_symbol,_` on macOS and +`--export-dynamic-symbol=` on Linux. See [`cli/build.rs`](../build.rs). + +On Windows, you need to generate the `.def` file by running +[`tools/napi/generate_link_win.js`](../../tools/napi/generate_link_win.js). -- cgit v1.2.3