Files
quickjs-rs/src/bindings.rs
2020-11-28 13:27:17 +08:00

1188 lines
38 KiB
Rust

use std::{
collections::HashMap,
ffi::CString,
os::raw::{c_char, c_int, c_void},
sync::Mutex,
};
use libquickjs_sys as q;
#[cfg(feature = "bigint")]
use crate::value::{bigint::BigIntOrI64, BigInt};
use crate::{
callback::{Arguments, Callback},
console::ConsoleBackend,
droppable_value::DroppableValue,
ContextError, ExecutionError, JsValue, ValueError,
};
// 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_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;
/// Free a JSValue.
/// This function is the equivalent of JS_FreeValue from quickjs, which can not
/// be used due to being `static inline`.
unsafe fn free_value(context: *mut q::JSContext, value: q::JSValue) {
// All tags < 0 are garbage collected and need to be freed.
if value.tag < 0 {
// This transmute is OK since if tag < 0, the union will be a refcount
// pointer.
let ptr = value.u.ptr as *mut q::JSRefCountHeader;
let pref: &mut q::JSRefCountHeader = &mut *ptr;
pref.ref_count -= 1;
if pref.ref_count <= 0 {
q::__JS_FreeValue(context, value);
}
}
}
#[cfg(feature = "chrono")]
fn js_date_constructor(context: *mut q::JSContext) -> q::JSValue {
let global = unsafe { q::JS_GetGlobalObject(context) };
assert_eq!(global.tag, TAG_OBJECT);
let date_constructor = unsafe {
q::JS_GetPropertyStr(
context,
global,
std::ffi::CStr::from_bytes_with_nul(b"Date\0")
.unwrap()
.as_ptr(),
)
};
assert_eq!(date_constructor.tag, TAG_OBJECT);
unsafe { free_value(context, global) };
date_constructor
}
#[cfg(feature = "bigint")]
fn js_create_bigint_function(context: *mut q::JSContext) -> q::JSValue {
let global = unsafe { q::JS_GetGlobalObject(context) };
assert_eq!(global.tag, TAG_OBJECT);
let bigint_function = unsafe {
q::JS_GetPropertyStr(
context,
global,
std::ffi::CStr::from_bytes_with_nul(b"BigInt\0")
.unwrap()
.as_ptr(),
)
};
assert_eq!(bigint_function.tag, TAG_OBJECT);
unsafe { free_value(context, global) };
bigint_function
}
/// Serialize a Rust value into a quickjs runtime value.
fn serialize_value(context: *mut q::JSContext, value: JsValue) -> Result<q::JSValue, ValueError> {
let v = match value {
JsValue::Null => q::JSValue {
u: q::JSValueUnion { int32: 0 },
tag: TAG_NULL,
},
JsValue::Bool(flag) => q::JSValue {
u: q::JSValueUnion {
int32: if flag { 1 } else { 0 },
},
tag: TAG_BOOL,
},
JsValue::Int(val) => q::JSValue {
u: q::JSValueUnion { int32: val },
tag: TAG_INT,
},
JsValue::Float(val) => q::JSValue {
u: q::JSValueUnion { float64: val },
tag: TAG_FLOAT64,
},
JsValue::String(val) => {
let qval = unsafe {
q::JS_NewStringLen(context, val.as_ptr() as *const c_char, val.len() as _)
};
if qval.tag == TAG_EXCEPTION {
return Err(ValueError::Internal(
"Could not create string in runtime".into(),
));
}
qval
}
JsValue::Array(values) => {
// Allocate a new array in the runtime.
let arr = unsafe { q::JS_NewArray(context) };
if arr.tag == TAG_EXCEPTION {
return Err(ValueError::Internal(
"Could not create array in runtime".into(),
));
}
for (index, value) in values.into_iter().enumerate() {
let qvalue = match serialize_value(context, value) {
Ok(qval) => qval,
Err(e) => {
// Make sure to free the array if a individual element
// fails.
unsafe {
free_value(context, arr);
}
return Err(e);
}
};
let ret = unsafe {
q::JS_DefinePropertyValueUint32(
context,
arr,
index as u32,
qvalue,
q::JS_PROP_C_W_E as i32,
)
};
if ret < 0 {
// Make sure to free the array if a individual
// element fails.
unsafe {
free_value(context, arr);
}
return Err(ValueError::Internal(
"Could not append element to array".into(),
));
}
}
arr
}
JsValue::Object(map) => {
let obj = unsafe { q::JS_NewObject(context) };
if obj.tag == TAG_EXCEPTION {
return Err(ValueError::Internal("Could not create object".into()));
}
for (key, value) in map {
let ckey = make_cstring(key)?;
let qvalue = serialize_value(context, value).map_err(|e| {
// Free the object if a property failed.
unsafe {
free_value(context, obj);
}
e
})?;
let ret = unsafe {
q::JS_DefinePropertyValueStr(
context,
obj,
ckey.as_ptr(),
qvalue,
q::JS_PROP_C_W_E as i32,
)
};
if ret < 0 {
// Free the object if a property failed.
unsafe {
free_value(context, obj);
}
return Err(ValueError::Internal(
"Could not add add property to object".into(),
));
}
}
obj
}
#[cfg(feature = "chrono")]
JsValue::Date(datetime) => {
let date_constructor = js_date_constructor(context);
let f = datetime.timestamp_millis() as f64;
let timestamp = q::JSValue {
u: q::JSValueUnion { float64: f },
tag: TAG_FLOAT64,
};
let mut args = vec![timestamp];
let value = unsafe {
q::JS_CallConstructor(
context,
date_constructor,
args.len() as i32,
args.as_mut_ptr(),
)
};
unsafe {
free_value(context, date_constructor);
}
if value.tag != TAG_OBJECT {
return Err(ValueError::Internal(
"Could not construct Date object".into(),
));
}
value
}
#[cfg(feature = "bigint")]
JsValue::BigInt(int) => match int.inner {
BigIntOrI64::Int(int) => unsafe { q::JS_NewBigInt64(context, int) },
BigIntOrI64::BigInt(bigint) => {
let bigint_string = bigint.to_str_radix(10);
let s = unsafe {
q::JS_NewStringLen(
context,
bigint_string.as_ptr() as *const c_char,
bigint_string.len() as q::size_t,
)
};
let s = DroppableValue::new(s, |&mut s| unsafe {
free_value(context, s);
});
if (*s).tag != TAG_STRING {
return Err(ValueError::Internal(
"Could not construct String object needed to create BigInt object".into(),
));
}
let mut args = vec![*s];
let bigint_function = js_create_bigint_function(context);
let bigint_function =
DroppableValue::new(bigint_function, |&mut bigint_function| unsafe {
free_value(context, bigint_function);
});
let js_bigint = unsafe {
q::JS_Call(
context,
*bigint_function,
js_null_value(),
1,
args.as_mut_ptr(),
)
};
if js_bigint.tag != TAG_BIG_INT {
return Err(ValueError::Internal(
"Could not construct BigInt object".into(),
));
}
js_bigint
}
},
JsValue::__NonExhaustive => unreachable!(),
};
Ok(v)
}
fn deserialize_array(
context: *mut q::JSContext,
raw_value: &q::JSValue,
) -> Result<JsValue, ValueError> {
assert_eq!(raw_value.tag, TAG_OBJECT);
let length_name = make_cstring("length")?;
let len_raw = unsafe { q::JS_GetPropertyStr(context, *raw_value, length_name.as_ptr()) };
let len_res = deserialize_value(context, &len_raw);
unsafe { free_value(context, len_raw) };
let len = match len_res? {
JsValue::Int(x) => x,
_ => {
return Err(ValueError::Internal(
"Could not determine array length".into(),
));
}
};
let mut values = Vec::new();
for index in 0..(len as usize) {
let value_raw = unsafe { q::JS_GetPropertyUint32(context, *raw_value, index as u32) };
if value_raw.tag == TAG_EXCEPTION {
return Err(ValueError::Internal("Could not build array".into()));
}
let value_res = deserialize_value(context, &value_raw);
unsafe { free_value(context, value_raw) };
let value = value_res?;
values.push(value);
}
Ok(JsValue::Array(values))
}
fn deserialize_object(context: *mut q::JSContext, obj: &q::JSValue) -> Result<JsValue, ValueError> {
assert_eq!(obj.tag, TAG_OBJECT);
let mut properties: *mut q::JSPropertyEnum = std::ptr::null_mut();
let mut count: u32 = 0;
let flags = (q::JS_GPN_STRING_MASK | q::JS_GPN_SYMBOL_MASK | q::JS_GPN_ENUM_ONLY) as i32;
let ret =
unsafe { q::JS_GetOwnPropertyNames(context, &mut properties, &mut count, *obj, flags) };
if ret != 0 {
return Err(ValueError::Internal(
"Could not get object properties".into(),
));
}
// TODO: refactor into a more Rust-idiomatic iterator wrapper.
let properties = DroppableValue::new(properties, |&mut properties| {
for index in 0..count {
let prop = unsafe { properties.offset(index as isize) };
unsafe {
q::JS_FreeAtom(context, (*prop).atom);
}
}
unsafe {
q::js_free(context, properties as *mut std::ffi::c_void);
}
});
let mut map = HashMap::new();
for index in 0..count {
let prop = unsafe { (*properties).offset(index as isize) };
let raw_value = unsafe { q::JS_GetPropertyInternal(context, *obj, (*prop).atom, *obj, 0) };
if raw_value.tag == TAG_EXCEPTION {
return Err(ValueError::Internal("Could not get object property".into()));
}
let value_res = deserialize_value(context, &raw_value);
unsafe {
free_value(context, raw_value);
}
let value = value_res?;
let key_value = unsafe { q::JS_AtomToString(context, (*prop).atom) };
if key_value.tag == TAG_EXCEPTION {
return Err(ValueError::Internal(
"Could not get object property name".into(),
));
}
let key_res = deserialize_value(context, &key_value);
unsafe {
free_value(context, key_value);
}
let key = match key_res? {
JsValue::String(s) => s,
_ => {
return Err(ValueError::Internal("Could not get property name".into()));
}
};
map.insert(key, value);
}
Ok(JsValue::Object(map))
}
fn deserialize_value(
context: *mut q::JSContext,
value: &q::JSValue,
) -> Result<JsValue, ValueError> {
let r = value;
match r.tag {
// Int.
TAG_INT => {
let val = unsafe { r.u.int32 };
Ok(JsValue::Int(val))
}
// Bool.
TAG_BOOL => {
let raw = unsafe { r.u.int32 };
let val = raw > 0;
Ok(JsValue::Bool(val))
}
// Null.
TAG_NULL => Ok(JsValue::Null),
// Undefined.
TAG_UNDEFINED => Ok(JsValue::Null),
// Float.
TAG_FLOAT64 => {
let val = unsafe { r.u.float64 };
Ok(JsValue::Float(val))
}
// String.
TAG_STRING => {
let ptr = unsafe { q::JS_ToCStringLen2(context, std::ptr::null_mut(), *r, 0) };
if ptr.is_null() {
return Err(ValueError::Internal(
"Could not convert string: got a null pointer".into(),
));
}
let cstr = unsafe { std::ffi::CStr::from_ptr(ptr) };
let s = cstr
.to_str()
.map_err(ValueError::InvalidString)?
.to_string();
// Free the c string.
unsafe { q::JS_FreeCString(context, ptr) };
Ok(JsValue::String(s))
}
// Object.
TAG_OBJECT => {
let is_array = unsafe { q::JS_IsArray(context, *r) } > 0;
if is_array {
deserialize_array(context, r)
} else {
#[cfg(feature = "chrono")]
{
use chrono::offset::TimeZone;
let date_constructor = js_date_constructor(context);
let is_date = unsafe { q::JS_IsInstanceOf(context, *r, date_constructor) > 0 };
if is_date {
let getter = unsafe {
q::JS_GetPropertyStr(
context,
*r,
std::ffi::CStr::from_bytes_with_nul(b"getTime\0")
.unwrap()
.as_ptr(),
)
};
assert_eq!(getter.tag, TAG_OBJECT);
let timestamp_raw =
unsafe { q::JS_Call(context, getter, *r, 0, std::ptr::null_mut()) };
unsafe {
free_value(context, getter);
free_value(context, date_constructor);
};
let res = if timestamp_raw.tag != TAG_FLOAT64 {
Err(ValueError::Internal(
"Could not convert 'Date' instance to timestamp".into(),
))
} else {
let f = unsafe { timestamp_raw.u.float64 } as i64;
let datetime = chrono::Utc.timestamp_millis(f);
Ok(JsValue::Date(datetime))
};
return res;
} else {
unsafe { free_value(context, date_constructor) };
}
}
deserialize_object(context, r)
}
}
// BigInt
#[cfg(feature = "bigint")]
TAG_BIG_INT => {
let mut int: i64 = 0;
let ret = unsafe { q::JS_ToBigInt64(context, &mut int, *r) };
if ret == 0 {
Ok(JsValue::BigInt(BigInt {
inner: BigIntOrI64::Int(int),
}))
} else {
let ptr = unsafe { q::JS_ToCStringLen2(context, std::ptr::null_mut(), *r, 0) };
if ptr.is_null() {
return Err(ValueError::Internal(
"Could not convert BigInt to string: got a null pointer".into(),
));
}
let cstr = unsafe { std::ffi::CStr::from_ptr(ptr) };
let bigint = num_bigint::BigInt::parse_bytes(cstr.to_bytes(), 10).unwrap();
// Free the c string.
unsafe { q::JS_FreeCString(context, ptr) };
Ok(JsValue::BigInt(BigInt {
inner: BigIntOrI64::BigInt(bigint),
}))
}
}
x => Err(ValueError::Internal(format!(
"Unhandled JS_TAG value: {}",
x
))),
}
}
/// Helper for creating CStrings.
fn make_cstring(value: impl Into<Vec<u8>>) -> Result<CString, ValueError> {
CString::new(value).map_err(ValueError::StringWithZeroBytes)
}
/// Helper to construct null JsValue
fn js_null_value() -> q::JSValue {
q::JSValue {
u: q::JSValueUnion { int32: 0 },
tag: TAG_NULL,
}
}
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 {
free_value(self.context.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(?)"),
_ => write!(f, "?"),
}
}
}
impl<'a> OwnedValueRef<'a> {
pub fn new(context: &'a ContextWrapper, value: q::JSValue) -> Self {
Self { context, value }
}
/// Get the inner JSValue without freeing in drop.
///
/// Unsafe because the caller is responsible for freeing the value.
//unsafe fn into_inner(mut self) -> q::JSValue {
//let v = self.value;
//self.value = q::JSValue {
//u: q::JSValueUnion { int32: 0 },
//tag: TAG_NULL,
//};
//v
//}
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 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),
}
}
}
/// 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 {
free_value(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 '{}' not found",
name
)))
} else {
Ok(OwnedValueRef::new(self.value.context, raw))
}
}
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 { self.set_property_raw(name, qval.value) }
// }
}
/*
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,
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<OwnedValueRef<'_>, ExecutionError> {
let serialized = serialize_value(self.context, value)?;
Ok(OwnedValueRef::new(self, serialized))
}
// Deserialize a quickjs runtime value into a Rust value.
fn to_value(&self, value: &q::JSValue) -> Result<JsValue, ValueError> {
deserialize_value(self.context, value)
}
/// Get the global object.
pub fn global(&self) -> Result<OwnedObjectRef<'_>, ExecutionError> {
let global_raw = unsafe { q::JS_GetGlobalObject(self.context) };
let global_ref = OwnedValueRef::new(self, global_raw);
let global = OwnedObjectRef::new(global_ref)?;
Ok(global)
}
/// Get the last exception from the runtime, and if present, convert it to a ExceptionError.
fn get_exception(&self) -> Option<ExecutionError> {
let raw = unsafe { q::JS_GetException(self.context) };
let value = OwnedValueRef::new(self, raw);
if value.is_null() {
None
} else {
let err = if value.is_exception() {
ExecutionError::Internal("Could get exception from runtime".into())
} else {
match value.to_string() {
Ok(strval) => {
if strval.contains("out of memory") {
ExecutionError::OutOfMemory
} else {
ExecutionError::Exception(JsValue::String(strval))
}
}
Err(_) => ExecutionError::Internal("Unknown exception".into()),
}
};
Some(err)
}
}
/// 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: OwnedValueRef<'a>,
) -> Result<OwnedValueRef<'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 = OwnedObjectRef::new(value)?;
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("__resolvePromise")?;
// Call the resolver code that sets the result values once
// the promise resolves.
self.call_function(resolver, 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("__promiseResult")?;
if res_val.is_bool() {
let ok = res_val.to_bool()?;
let value = global.property("__promiseValue")?;
if ok {
return self.resolve_value(value);
} else {
let err_msg = value.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<OwnedValueRef<'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 = OwnedValueRef::new(self, value_raw);
self.resolve_value(value)
}
/*
/// Call a constructor function.
fn call_constructor<'a>(
&'a self,
function: OwnedValueRef<'a>,
args: Vec<OwnedValueRef<'a>>,
) -> Result<OwnedValueRef<'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 = OwnedValueRef::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: OwnedValueRef<'a>,
args: Vec<OwnedValueRef<'a>>,
) -> Result<OwnedValueRef<'a>, ExecutionError> {
let mut qargs = args.iter().map(|arg| arg.value).collect::<Vec<_>>();
let qres_raw = unsafe {
q::JS_Call(
self.context,
function.value,
js_null_value(),
qargs.len() as i32,
qargs.as_mut_ptr(),
)
};
let qres = OwnedValueRef::new(self, qres_raw);
self.resolve_value(qres)
}
/// 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| deserialize_value(context, raw))
.collect::<Result<Vec<_>, _>>()?;
match callback.call(args) {
Ok(Ok(result)) => {
let serialized = 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<'a, F>(
&'a self,
callback: impl Callback<F> + 'static,
) -> Result<q::JSValue, 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 = 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 cfunc =
unsafe { q::JS_NewCFunctionData(self.context, trampoline, argcount, 0, 1, data) };
if cfunc.tag != TAG_OBJECT {
return Err(ExecutionError::Internal("Could not create callback".into()));
}
Ok(cfunc)
}
pub fn add_callback<'a, F>(
&'a self,
name: &str,
callback: impl Callback<F> + 'static,
) -> Result<(), ExecutionError> {
let cfunc = self.create_callback(callback)?;
let global = self.global()?;
unsafe {
global.set_property_raw(name, cfunc)?;
}
Ok(())
}
}