chore: (cargo serde example)

README.md

@@ -158,9 +158,13 @@ To compile the entire project, run the following commands:
 ```sh
 $ just rust
 $ just php
+$ composer install
 $ php -d extension=wasm examples/simple.php
 ```
-
+Additionally, to compile one of the cargo examples, run the following:
+```bash
+$ just compile-and-run-cargo-example serde
+```
 (Yes, you need [`just`](https://github.com/casey/just/)).
 
 ## Testing

examples/cargo/serde/.gitignore

@@ -0,0 +1,2 @@
+serde.wasm
+target

examples/cargo/serde/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+publish = false
+name = "php-ext-wasm-cargo-serde-example"
+version = "1.0.0"
+edition = "2018"
+
+[lib]
+path = "serde.rs"
+crate-type = ["cdylib"]
+
+[dependencies]
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"

examples/cargo/serde/serde.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types = 1);
+
+require_once __DIR__ . '/../../../vendor/autoload.php';
+
+// Instantiate the module.
+$instance = new Wasm\Instance(__DIR__ . '/serde.wasm');
+
+// Set the subject to greet.
+$subject = 'Hello, this is PHP.';
+$length_of_subject = strlen($subject);
+
+// Allocate memory for the subject, and get a pointer to it.
+$input_pointer = $instance->allocate($length_of_subject);
+
+// Write the subject into the memory.
+$memory_buffer = $instance->getMemoryBuffer();
+$memory = new Wasm\Uint8Array($memory_buffer, $input_pointer);
+
+for ($nth = 0; $nth < $length_of_subject; ++$nth) {
+	$memory[$nth] = ord($subject[$nth]);
+}
+
+// C-string terminates by NULL.
+$memory[$nth] = 0;
+
+// Run the `greet` function. Give the pointer to the subject.
+$output_pointer = $instance->to_subject($input_pointer);
+
+// Read the result of the `greet` function.
+$memory = new Wasm\Uint8Array($memory_buffer, $output_pointer);
+
+$output = '';
+$nth = 0;
+
+while (0 !== $memory[$nth]) {
+	$output .= chr($memory[$nth]);
+	++$nth;
+}
+
+$length_of_output = $nth;
+
+var_dump($output);
+var_dump(json_decode($output));
+
+// Deallocate the subject, and the output.
+$instance->deallocate($input_pointer, $length_of_subject);
+$instance->deallocate($output_pointer, $length_of_output);

examples/cargo/serde/serde.rs

@@ -0,0 +1,35 @@
+use std::ffi::{CStr, CString};
+use std::mem;
+use std::borrow::Cow;
+use std::os::raw::{c_char, c_void};
+use serde::{Serialize, Deserialize};
+
+
+#[derive(Serialize, Deserialize, Debug)]
+struct Subject<'a> {
+    subject: Cow<'a, str>,
+}
+
+#[no_mangle]
+pub extern fn allocate(size: usize) -> *mut c_void {
+    let mut buffer = Vec::with_capacity(size);
+    let pointer = buffer.as_mut_ptr();
+    mem::forget(buffer);
+
+    pointer as *mut c_void
+}
+
+#[no_mangle]
+pub extern fn deallocate(pointer: *mut c_void, capacity: usize) {
+    unsafe {
+        let _ = Vec::from_raw_parts(pointer, 0, capacity);
+    }
+}
+
+#[no_mangle]
+pub extern fn to_subject(subject: *mut c_char) -> *mut c_char {
+    let subject = unsafe { CStr::from_ptr(subject).to_string_lossy() };
+    let point = Subject { subject };
+    let serialized = serde_json::to_string(&point).unwrap();
+    unsafe { CString::from_vec_unchecked(serialized.as_bytes().to_vec()) }.into_raw()
+}

justfile

@@ -8,6 +8,14 @@ compile-wasm FILE='examples/simple':
 	mv {{FILE}}.opt.wasm {{FILE}}.wasm
 	rm {{FILE}}.raw.wasm
 
+compile-and-run-cargo-example FILE='serde':
+	#!/usr/bin/env bash
+	set -euo pipefail
+	cd examples/cargo/{{FILE}}
+	cargo +nightly build --target wasm32-unknown-unknown
+	cp target/wasm32-unknown-unknown/debug/php_ext_wasm_cargo_{{FILE}}_example.wasm {{FILE}}.wasm
+	php -d extension=wasm {{FILE}}.php
+
 # Compile the Rust part.
 rust:
 	cargo build --release