feat: add greet-rs

.gitignore

@@ -6,6 +6,7 @@ target/
 wasm/pkg/
 node_modules/
 *.o
+*.so
 
 # These are backup files generated by rustfmt
 **/*.rs.bk

live-reload-rust/greet-rs/Cargo.lock

@@ -0,0 +1,5 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "greet-rs"
+version = "0.1.0"

live-reload-rust/greet-rs/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "greet-rs"
+version = "0.1.0"
+authors = ["Hatter Jiang <jht5945@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

live-reload-rust/greet-rs/README.md

@@ -0,0 +1,11 @@
+build libgreet.so
+
+
+direct build or use build.rs:
+RUSTFLAGS="-L ${PWD}/.." cargo build
+
+
+run:
+LD_LIBRARY_PATH="${PWD}/.." ./target/debug/greet-rs
+
+

live-reload-rust/greet-rs/build.rs

@@ -0,0 +1,10 @@
+use std::path::PathBuf;
+
+fn main() {
+    let manifest_dir =
+        PathBuf::from(std::env::var_os("CARGO_MANIFEST_DIR").expect("manifest dir should be set"));
+    let lib_dir = manifest_dir
+        .parent()
+        .expect("manifest dir should have a parent");
+    println!("cargo:rustc-link-search={}", lib_dir.display());
+}

live-reload-rust/greet-rs/src/main.rs

@@ -0,0 +1,14 @@
+use std::{ffi::CString, os::raw::c_char};
+
+#[link(name = "greet")]
+extern "C" {
+    fn greet(name: *const c_char);
+}
+
+fn main() {
+    let name = CString::new("fresh coffee").unwrap();
+    unsafe {
+        greet(name.as_ptr());
+    }
+}
+

live-reload-rust/greet.c-compile-shared.sh

@@ -0,0 +1 @@
+gcc -Wall -shared greet.c -o libgreet.so

live-reload-rust/load-shared.c

@@ -0,0 +1,21 @@
+#include <dlfcn.h>
+#include <stdio.h>
+
+typedef void (*greet_t)(const char *name);
+
+int main(void) {
+    // this was `./libmain.so`
+    void *lib = dlopen("./libgreet.so", RTLD_LAZY);
+    if (!lib) {
+        fprintf(stderr, "failed to load library\n");
+        return 1;
+    }
+    greet_t greet = (greet_t) dlsym(lib, "greet");
+    if (!lib) {
+        fprintf(stderr, "could not look up symbol 'greet'\n");
+        return 1;
+    }
+    greet("venus");
+    dlclose(lib);
+    return 0;
+}