quick-js-datepatch/src/bindings/mod.rs

736 lines
23 KiB
Rust

mod compile;
mod convert;
mod droppable_value;
mod value;
use std::{
ffi::CString,
os::raw::{c_int, c_void},
sync::Mutex,
};
use libquickjs_sys as q;
use crate::{
callback::{Arguments, Callback},
console::ConsoleBackend,
ContextError, ExecutionError, JsValue, ValueError,
};
use value::{JsFunction, OwnedJsObject};
#[allow(unused_imports)]
pub use value::{JsCompiledFunction, OwnedJsValue};
// JS_TAG_* constants from quickjs.
// For some reason bindgen does not pick them up.
#[cfg(feature = "bigint")]
const TAG_BIG_INT: i64 = -10;
const TAG_STRING: i64 = -7;
const TAG_FUNCTION_BYTECODE: i64 = -2;
const TAG_OBJECT: i64 = -1;
const TAG_INT: i64 = 0;
const TAG_BOOL: i64 = 1;
const TAG_NULL: i64 = 2;
const TAG_UNDEFINED: i64 = 3;
const TAG_EXCEPTION: i64 = 6;
const TAG_FLOAT64: i64 = 7;
/// Helper for creating CStrings.
fn make_cstring(value: impl Into<Vec<u8>>) -> Result<CString, ValueError> {
CString::new(value).map_err(ValueError::StringWithZeroBytes)
}
type WrappedCallback = dyn Fn(c_int, *mut q::JSValue) -> q::JSValue;
/// Taken from: https://s3.amazonaws.com/temp.michaelfbryan.com/callbacks/index.html
///
/// Create a C wrapper function for a Rust closure to enable using it as a
/// callback function in the Quickjs runtime.
///
/// Both the boxed closure and the boxed data are returned and must be stored
/// by the caller to guarantee they stay alive.
unsafe fn build_closure_trampoline<F>(
closure: F,
) -> ((Box<WrappedCallback>, Box<q::JSValue>), q::JSCFunctionData)
where
F: Fn(c_int, *mut q::JSValue) -> q::JSValue + 'static,
{
unsafe extern "C" fn trampoline<F>(
_ctx: *mut q::JSContext,
_this: q::JSValue,
argc: c_int,
argv: *mut q::JSValue,
_magic: c_int,
data: *mut q::JSValue,
) -> q::JSValue
where
F: Fn(c_int, *mut q::JSValue) -> q::JSValue,
{
let closure_ptr = (*data).u.ptr;
let closure: &mut F = &mut *(closure_ptr as *mut F);
(*closure)(argc, argv)
}
let boxed_f = Box::new(closure);
let data = Box::new(q::JSValue {
u: q::JSValueUnion {
ptr: (&*boxed_f) as *const F as *mut c_void,
},
tag: TAG_NULL,
});
((boxed_f, data), Some(trampoline::<F>))
}
/// OwnedValueRef wraps a Javascript value from the quickjs runtime.
/// It prevents leaks by ensuring that the inner value is deallocated on drop.
pub struct OwnedValueRef<'a> {
context: &'a ContextWrapper,
value: q::JSValue,
}
impl<'a> Drop for OwnedValueRef<'a> {
fn drop(&mut self) {
unsafe {
q::JS_FreeValue(self.context.context, self.value);
}
}
}
impl<'a> Clone for OwnedValueRef<'a> {
fn clone(&self) -> Self {
Self::new_dup(self.context, self.value)
}
}
impl<'a> std::fmt::Debug for OwnedValueRef<'a> {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
match self.value.tag {
TAG_EXCEPTION => write!(f, "Exception(?)"),
TAG_NULL => write!(f, "NULL"),
TAG_UNDEFINED => write!(f, "UNDEFINED"),
TAG_BOOL => write!(f, "Bool(?)",),
TAG_INT => write!(f, "Int(?)"),
TAG_FLOAT64 => write!(f, "Float(?)"),
TAG_STRING => write!(f, "String(?)"),
TAG_OBJECT => write!(f, "Object(?)"),
TAG_FUNCTION_BYTECODE => write!(f, "Bytecode(?)"),
_ => write!(f, "?"),
}
}
}
impl<'a> OwnedValueRef<'a> {
pub fn new(context: &'a ContextWrapper, value: q::JSValue) -> Self {
Self { context, value }
}
pub fn new_dup(context: &'a ContextWrapper, value: q::JSValue) -> Self {
let ret = Self::new(context, value);
unsafe { q::JS_DupValue(ret.context.context, ret.value) };
ret
}
/// Get the inner JSValue without freeing in drop.
///
/// Unsafe because the caller is responsible for freeing the returned value.
unsafe fn into_inner(self) -> q::JSValue {
let v = self.value;
std::mem::forget(self);
v
}
/// Get the inner JSValue without increasing ref count
pub(crate) fn as_inner(&self) -> &q::JSValue {
&self.value
}
/// Get the inner JSValue while increasing ref count, this is handy when you pass a JSValue to a new owner like e.g. setProperty
#[allow(dead_code)]
pub(crate) fn as_inner_dup(&self) -> &q::JSValue {
unsafe { q::JS_DupValue(self.context.context, self.value) };
&self.value
}
pub fn is_null(&self) -> bool {
self.value.tag == TAG_NULL
}
pub fn is_bool(&self) -> bool {
self.value.tag == TAG_BOOL
}
pub fn is_exception(&self) -> bool {
self.value.tag == TAG_EXCEPTION
}
pub fn is_object(&self) -> bool {
self.value.tag == TAG_OBJECT
}
pub fn is_string(&self) -> bool {
self.value.tag == TAG_STRING
}
pub fn is_compiled_function(&self) -> bool {
self.value.tag == TAG_FUNCTION_BYTECODE
}
pub fn to_string(&self) -> Result<String, ExecutionError> {
let value = if self.is_string() {
self.to_value()?
} else {
let raw = unsafe { q::JS_ToString(self.context.context, self.value) };
let value = OwnedValueRef::new(self.context, raw);
if value.value.tag != TAG_STRING {
return Err(ExecutionError::Exception(
"Could not convert value to string".into(),
));
}
value.to_value()?
};
Ok(value.as_str().unwrap().to_string())
}
pub fn to_value(&self) -> Result<JsValue, ValueError> {
self.context.to_value(&self.value)
}
pub fn to_bool(&self) -> Result<bool, ValueError> {
match self.to_value()? {
JsValue::Bool(b) => Ok(b),
_ => Err(ValueError::UnexpectedType),
}
}
#[cfg(test)]
pub fn get_ref_count(&self) -> i32 {
if self.value.tag < 0 {
// This transmute is OK since if tag < 0, the union will be a refcount
// pointer.
let ptr = unsafe { self.value.u.ptr as *mut q::JSRefCountHeader };
let pref: &mut q::JSRefCountHeader = &mut unsafe { *ptr };
pref.ref_count
} else {
-1
}
}
}
/// Wraps an object from the quickjs runtime.
/// Provides convenience property accessors.
pub struct OwnedObjectRef<'a> {
value: OwnedValueRef<'a>,
}
impl<'a> OwnedObjectRef<'a> {
pub fn new(value: OwnedValueRef<'a>) -> Result<Self, ValueError> {
if value.value.tag != TAG_OBJECT {
Err(ValueError::Internal("Expected an object".into()))
} else {
Ok(Self { value })
}
}
fn into_value(self) -> OwnedValueRef<'a> {
self.value
}
/// Get the tag of a property.
fn property_tag(&self, name: &str) -> Result<i64, ValueError> {
let cname = make_cstring(name)?;
let raw = unsafe {
q::JS_GetPropertyStr(self.value.context.context, self.value.value, cname.as_ptr())
};
let t = raw.tag;
unsafe {
q::JS_FreeValue(self.value.context.context, raw);
}
Ok(t)
}
/// Determine if the object is a promise by checking the presence of
/// a 'then' and a 'catch' property.
fn is_promise(&self) -> Result<bool, ValueError> {
if self.property_tag("then")? == TAG_OBJECT && self.property_tag("catch")? == TAG_OBJECT {
Ok(true)
} else {
Ok(false)
}
}
pub fn property(&self, name: &str) -> Result<OwnedValueRef<'a>, ExecutionError> {
let cname = make_cstring(name)?;
let raw = unsafe {
q::JS_GetPropertyStr(self.value.context.context, self.value.value, cname.as_ptr())
};
if raw.tag == TAG_EXCEPTION {
Err(ExecutionError::Internal(format!(
"Exception while getting property '{name}'"
)))
} else if raw.tag == TAG_UNDEFINED {
Err(ExecutionError::Internal(format!(
"Property '{name}' not found"
)))
} else {
Ok(OwnedValueRef::new(self.value.context, raw))
}
}
// Set a property on an object.
// NOTE: this method takes ownership of the `JSValue`, so it must not be
// freed later.
unsafe fn set_property_raw(&self, name: &str, value: q::JSValue) -> Result<(), ExecutionError> {
let cname = make_cstring(name)?;
let ret = q::JS_SetPropertyStr(
self.value.context.context,
self.value.value,
cname.as_ptr(),
value,
);
if ret < 0 {
Err(ExecutionError::Exception("Could not set property".into()))
} else {
Ok(())
}
}
pub fn set_property(&self, name: &str, value: JsValue) -> Result<(), ExecutionError> {
let qval = self.value.context.serialize_value(value)?;
unsafe {
// set_property_raw takes ownership, so we must prevent a free.
self.set_property_raw(name, qval.extract())?;
}
Ok(())
}
}
/*
type ModuleInit = dyn Fn(*mut q::JSContext, *mut q::JSModuleDef);
thread_local! {
static NATIVE_MODULE_INIT: RefCell<Option<Box<ModuleInit>>> = RefCell::new(None);
}
unsafe extern "C" fn native_module_init(
ctx: *mut q::JSContext,
m: *mut q::JSModuleDef,
) -> ::std::os::raw::c_int {
NATIVE_MODULE_INIT.with(|init| {
let init = init.replace(None).unwrap();
init(ctx, m);
});
0
}
*/
/// Wraps a quickjs context.
///
/// Cleanup of the context happens in drop.
pub struct ContextWrapper {
runtime: *mut q::JSRuntime,
pub(crate) context: *mut q::JSContext,
/// Stores callback closures and quickjs data pointers.
/// This array is write-only and only exists to ensure the lifetime of
/// the closure.
// A Mutex is used over a RefCell because it needs to be unwind-safe.
callbacks: Mutex<Vec<(Box<WrappedCallback>, Box<q::JSValue>)>>,
}
impl Drop for ContextWrapper {
fn drop(&mut self) {
unsafe {
q::JS_FreeContext(self.context);
q::JS_FreeRuntime(self.runtime);
}
}
}
impl ContextWrapper {
/// Initialize a wrapper by creating a JSRuntime and JSContext.
pub fn new(memory_limit: Option<usize>) -> Result<Self, ContextError> {
let runtime = unsafe { q::JS_NewRuntime() };
if runtime.is_null() {
return Err(ContextError::RuntimeCreationFailed);
}
// Configure memory limit if specified.
if let Some(limit) = memory_limit {
unsafe {
q::JS_SetMemoryLimit(runtime, limit as _);
}
}
let context = unsafe { q::JS_NewContext(runtime) };
if context.is_null() {
unsafe {
q::JS_FreeRuntime(runtime);
}
return Err(ContextError::ContextCreationFailed);
}
// Initialize the promise resolver helper code.
// This code is needed by Self::resolve_value
let wrapper = Self {
runtime,
context,
callbacks: Mutex::new(Vec::new()),
};
Ok(wrapper)
}
// See console standard: https://console.spec.whatwg.org
pub fn set_console(&self, backend: Box<dyn ConsoleBackend>) -> Result<(), ExecutionError> {
use crate::console::Level;
self.add_callback("__console_write", move |args: Arguments| {
let mut args = args.into_vec();
if args.len() > 1 {
let level_raw = args.remove(0);
let level_opt = level_raw.as_str().and_then(|v| match v {
"trace" => Some(Level::Trace),
"debug" => Some(Level::Debug),
"log" => Some(Level::Log),
"info" => Some(Level::Info),
"warn" => Some(Level::Warn),
"error" => Some(Level::Error),
_ => None,
});
if let Some(level) = level_opt {
backend.log(level, args);
}
}
})?;
self.eval(
r#"
globalThis.console = {
trace: (...args) => {
globalThis.__console_write("trace", ...args);
},
debug: (...args) => {
globalThis.__console_write("debug", ...args);
},
log: (...args) => {
globalThis.__console_write("log", ...args);
},
info: (...args) => {
globalThis.__console_write("info", ...args);
},
warn: (...args) => {
globalThis.__console_write("warn", ...args);
},
error: (...args) => {
globalThis.__console_write("error", ...args);
},
};
"#,
)?;
Ok(())
}
/// Reset the wrapper by creating a new context.
pub fn reset(self) -> Result<Self, ContextError> {
unsafe {
q::JS_FreeContext(self.context);
};
self.callbacks.lock().unwrap().clear();
let context = unsafe { q::JS_NewContext(self.runtime) };
if context.is_null() {
return Err(ContextError::ContextCreationFailed);
}
let mut s = self;
s.context = context;
Ok(s)
}
pub fn serialize_value(&self, value: JsValue) -> Result<OwnedJsValue<'_>, ExecutionError> {
let serialized = convert::serialize_value(self.context, value)?;
Ok(OwnedJsValue::new(self, serialized))
}
// Deserialize a quickjs runtime value into a Rust value.
pub(crate) fn to_value(&self, value: &q::JSValue) -> Result<JsValue, ValueError> {
convert::deserialize_value(self.context, value)
}
/// Get the global object.
pub fn global(&self) -> Result<OwnedJsObject<'_>, ExecutionError> {
let global_raw = unsafe { q::JS_GetGlobalObject(self.context) };
let global_ref = OwnedJsValue::new(self, global_raw);
let global = global_ref.try_into_object()?;
Ok(global)
}
/// Get the last exception from the runtime, and if present, convert it to a ExceptionError.
pub(crate) fn get_exception(&self) -> Option<ExecutionError> {
let value = unsafe {
let raw = q::JS_GetException(self.context);
OwnedJsValue::new(self, raw)
};
if value.is_null() {
None
} else if value.is_exception() {
Some(ExecutionError::Internal(
"Could get exception from runtime".into(),
))
} else {
match value.js_to_string() {
Ok(strval) => {
if strval.contains("out of memory") {
Some(ExecutionError::OutOfMemory)
} else {
Some(ExecutionError::Exception(JsValue::String(strval)))
}
}
Err(e) => Some(e),
}
}
}
/// Returns `Result::Err` when an error ocurred.
pub(crate) fn ensure_no_excpetion(&self) -> Result<(), ExecutionError> {
if let Some(e) = self.get_exception() {
Err(e)
} else {
Ok(())
}
}
/// If the given value is a promise, run the event loop until it is
/// resolved, and return the final value.
fn resolve_value<'a>(
&'a self,
value: OwnedJsValue<'a>,
) -> Result<OwnedJsValue<'a>, ExecutionError> {
if value.is_exception() {
let err = self
.get_exception()
.unwrap_or_else(|| ExecutionError::Exception("Unknown exception".into()));
Err(err)
} else if value.is_object() {
let obj = value.try_into_object()?;
if obj.is_promise()? {
self.eval(
r#"
// Values:
// - undefined: promise not finished
// - false: error ocurred, __promiseError is set.
// - true: finished, __promiseSuccess is set.
var __promiseResult = 0;
var __promiseValue = 0;
var __resolvePromise = function(p) {
p
.then(value => {
__promiseResult = true;
__promiseValue = value;
})
.catch(e => {
__promiseResult = false;
__promiseValue = e;
});
}
"#,
)?;
let global = self.global()?;
let resolver = global
.property_require("__resolvePromise")?
.try_into_function()?;
// Call the resolver code that sets the result values once
// the promise resolves.
resolver.call(vec![obj.into_value()])?;
loop {
let flag = unsafe {
let wrapper_mut = self as *const Self as *mut Self;
let ctx_mut = &mut (*wrapper_mut).context;
q::JS_ExecutePendingJob(self.runtime, ctx_mut)
};
if flag < 0 {
let e = self.get_exception().unwrap_or_else(|| {
ExecutionError::Exception("Unknown exception".into())
});
return Err(e);
}
// Check if promise is finished.
let res_val = global.property_require("__promiseResult")?;
if res_val.is_bool() {
let ok = res_val.to_bool()?;
let value = global.property_require("__promiseValue")?;
if ok {
return self.resolve_value(value);
} else {
let err_msg = value.js_to_string()?;
return Err(ExecutionError::Exception(JsValue::String(err_msg)));
}
}
}
} else {
Ok(obj.into_value())
}
} else {
Ok(value)
}
}
/// Evaluate javascript code.
pub fn eval<'a>(&'a self, code: &str) -> Result<OwnedJsValue<'a>, ExecutionError> {
let filename = "script.js";
let filename_c = make_cstring(filename)?;
let code_c = make_cstring(code)?;
let value_raw = unsafe {
q::JS_Eval(
self.context,
code_c.as_ptr(),
code.len() as _,
filename_c.as_ptr(),
q::JS_EVAL_TYPE_GLOBAL as i32,
)
};
let value = OwnedJsValue::new(self, value_raw);
self.resolve_value(value)
}
/*
/// Call a constructor function.
fn call_constructor<'a>(
&'a self,
function: OwnedJsValue<'a>,
args: Vec<OwnedJsValue<'a>>,
) -> Result<OwnedJsValue<'a>, ExecutionError> {
let mut qargs = args.iter().map(|arg| arg.value).collect::<Vec<_>>();
let value_raw = unsafe {
q::JS_CallConstructor(
self.context,
function.value,
qargs.len() as i32,
qargs.as_mut_ptr(),
)
};
let value = OwnedJsValue::new(self, value_raw);
if value.is_exception() {
let err = self
.get_exception()
.unwrap_or_else(|| ExecutionError::Exception("Unknown exception".into()));
Err(err)
} else {
Ok(value)
}
}
*/
/// Call a JS function with the given arguments.
pub fn call_function<'a>(
&'a self,
function: JsFunction<'a>,
args: Vec<OwnedJsValue<'a>>,
) -> Result<OwnedJsValue<'a>, ExecutionError> {
let ret = function.call(args)?;
self.resolve_value(ret)
}
/// Helper for executing a callback closure.
fn exec_callback<F>(
context: *mut q::JSContext,
argc: c_int,
argv: *mut q::JSValue,
callback: &impl Callback<F>,
) -> Result<q::JSValue, ExecutionError> {
let result = std::panic::catch_unwind(|| {
let arg_slice = unsafe { std::slice::from_raw_parts(argv, argc as usize) };
let args = arg_slice
.iter()
.map(|raw| convert::deserialize_value(context, raw))
.collect::<Result<Vec<_>, _>>()?;
match callback.call(args) {
Ok(Ok(result)) => {
let serialized = convert::serialize_value(context, result)?;
Ok(serialized)
}
// TODO: better error reporting.
Ok(Err(e)) => Err(ExecutionError::Exception(JsValue::String(e))),
Err(e) => Err(e.into()),
}
});
match result {
Ok(r) => r,
Err(_e) => Err(ExecutionError::Internal("Callback panicked!".to_string())),
}
}
/// Add a global JS function that is backed by a Rust function or closure.
pub fn create_callback<F>(
&self,
callback: impl Callback<F> + 'static,
) -> Result<JsFunction, ExecutionError> {
let argcount = callback.argument_count() as i32;
let context = self.context;
let wrapper = move |argc: c_int, argv: *mut q::JSValue| -> q::JSValue {
match Self::exec_callback(context, argc, argv, &callback) {
Ok(value) => value,
// TODO: better error reporting.
Err(e) => {
let js_exception_value = match e {
ExecutionError::Exception(e) => e,
other => other.to_string().into(),
};
let js_exception =
convert::serialize_value(context, js_exception_value).unwrap();
unsafe {
q::JS_Throw(context, js_exception);
}
q::JSValue {
u: q::JSValueUnion { int32: 0 },
tag: TAG_EXCEPTION,
}
}
}
};
let (pair, trampoline) = unsafe { build_closure_trampoline(wrapper) };
let data = (&*pair.1) as *const q::JSValue as *mut q::JSValue;
self.callbacks.lock().unwrap().push(pair);
let obj = unsafe {
let f = q::JS_NewCFunctionData(self.context, trampoline, argcount, 0, 1, data);
OwnedJsValue::new(self, f)
};
let f = obj.try_into_function()?;
Ok(f)
}
pub fn add_callback<F>(
&self,
name: &str,
callback: impl Callback<F> + 'static,
) -> Result<(), ExecutionError> {
let cfunc = self.create_callback(callback)?;
let global = self.global()?;
global.set_property(name, cfunc.into_value())?;
Ok(())
}
}