Serde support

Cargo.toml

@@ -11,23 +11,30 @@ authors = ["Christoph Herzog <[email protected]>"]
 keywords = ["quickjs", "javascript", "js", "engine", "interpreter"]
 
 [package.metadata.docs.rs]
-features = [ "chrono", "bigint", "log" ]
+features = ["chrono", "bigint", "log"]
 
 [features]
 default = ["chrono"]
 patched = ["libquickjs-sys/patched"]
 bigint = ["num-bigint", "num-traits", "libquickjs-sys/patched"]
+serde = ["dep:quick-js-serde", "dep:serde"]
 
 [dependencies]
 libquickjs-sys = { version = ">= 0.9.0, < 0.10.0", path = "./libquickjs-sys" }
+quick-js-serde = { path = "./serde", optional = true }
+serde = { version = "1", optional = true }
 chrono = { version = "0.4.7", optional = true }
 num-bigint = { version = "0.2.2", optional = true }
 num-traits = { version = "0.2.0", optional = true }
 log = { version = "0.4.8", optional = true }
 once_cell = "1.2.0"
 
+[dev-dependencies]
+serde = { version = "1.0.176", features = ['derive'] }
+
 [workspace]
 members = [
     "libquickjs-sys",
+    "serde"
 ]
 

examples/serde.rs

@@ -0,0 +1,41 @@
+use quick_js::Context;
+use serde::Serialize;
+
+#[derive(Debug, Serialize)]
+pub struct Inner {
+    b: u8,
+}
+
+#[derive(Debug, Serialize)]
+pub struct Example {
+    a: Vec<Inner>,
+}
+
+fn main() {
+    let context = Context::new().unwrap();
+
+    let value = context.eval("1 + 2").unwrap();
+    println!("js: 1 + 2 = {:?}", value);
+
+    context
+        .add_callback("myCallback", |a: i32, b: i32| a + b * b)
+        .unwrap();
+
+    context
+        .set_global_serde(
+            "example",
+            &Example {
+                a: vec![Inner { b: 5 }, Inner { b: 6 }],
+            },
+        )
+        .unwrap();
+
+    let value = context
+        .eval(
+            r#"
+       JSON.stringify(example)
+"#,
+        )
+        .unwrap();
+    println!("js: JSON.stringify(example) = {:?}", value);
+}

libquickjs-sys/src/static-functions.rs

@@ -1,4 +1,3 @@
-
 extern "C" {
     fn JS_ValueGetTag_real(v: JSValue) -> i32;
     fn JS_DupValue_real(ctx: *mut JSContext, v: JSValue);
@@ -24,9 +23,26 @@ extern "C" {
     fn JS_IsSymbol_real(v: JSValue) -> bool;
     fn JS_IsObject_real(v: JSValue) -> bool;
     fn JS_ToUint32_real(ctx: *mut JSContext, pres: u32, val: JSValue) -> u32;
-    fn JS_SetProperty_real(ctx: *mut JSContext, this_obj: JSValue, prop: JSAtom, val: JSValue) -> ::std::os::raw::c_int;
-    fn JS_NewCFunction_real(ctx: *mut JSContext, func: *mut JSCFunction, name: *const ::std::os::raw::c_char,length: ::std::os::raw::c_int) -> JSValue;
-    fn JS_NewCFunctionMagic_real(ctx: *mut JSContext, func: *mut JSCFunctionMagic, name: *const ::std::os::raw::c_char, length: ::std::os::raw::c_int, cproto: JSCFunctionEnum, magic: ::std::os::raw::c_int) -> JSValue;
+    fn JS_SetProperty_real(
+        ctx: *mut JSContext,
+        this_obj: JSValue,
+        prop: JSAtom,
+        val: JSValue,
+    ) -> ::std::os::raw::c_int;
+    fn JS_NewCFunction_real(
+        ctx: *mut JSContext,
+        func: *mut JSCFunction,
+        name: *const ::std::os::raw::c_char,
+        length: ::std::os::raw::c_int,
+    ) -> JSValue;
+    fn JS_NewCFunctionMagic_real(
+        ctx: *mut JSContext,
+        func: *mut JSCFunctionMagic,
+        name: *const ::std::os::raw::c_char,
+        length: ::std::os::raw::c_int,
+        cproto: JSCFunctionEnum,
+        magic: ::std::os::raw::c_int,
+    ) -> JSValue;
 }
 
 pub unsafe fn JS_ValueGetTag(v: JSValue) -> i32 {
@@ -63,7 +79,8 @@ pub unsafe fn JS_NewInt32(ctx: *mut JSContext, v: i32) -> JSValue {
     JS_NewInt32_real(ctx, v)
 }
 
-/// create a new f64 value, please note that if the passed f64 fits in a i32 this will return a value with flag 0 (i32)
+/// create a new f64 value, please note that if the passed f64 fits in a i32
+/// this will return a value with flag 0 (i32)
 pub unsafe fn JS_NewFloat64(ctx: *mut JSContext, v: f64) -> JSValue {
     JS_NewFloat64_real(ctx, v)
 }
@@ -90,7 +107,7 @@ pub unsafe fn JS_IsNumber(v: JSValue) -> bool {
 
 /// check if a JSValue is a BigInt
 pub unsafe fn JS_IsBigInt(ctx: *mut JSContext, v: JSValue) -> bool {
-    JS_IsBigInt_real(ctx,v)
+    JS_IsBigInt_real(ctx, v)
 }
 
 /// check if a JSValue is a BigFloat
@@ -119,7 +136,7 @@ pub unsafe fn JS_IsUndefined(v: JSValue) -> bool {
 }
 
 /// check if a JSValue is an Exception
-pub unsafe fn JS_IsException(v: JSValue) -> bool{
+pub unsafe fn JS_IsException(v: JSValue) -> bool {
     JS_IsException_real(v)
 }
 
@@ -149,16 +166,33 @@ pub unsafe fn JS_ToUint32(ctx: *mut JSContext, pres: u32, val: JSValue) -> u32 {
 }
 
 /// set a property of an object identified by a JSAtom
-pub unsafe fn JS_SetProperty(ctx: *mut JSContext, this_obj: JSValue, prop: JSAtom, val: JSValue) -> ::std::os::raw::c_int {
+pub unsafe fn JS_SetProperty(
+    ctx: *mut JSContext,
+    this_obj: JSValue,
+    prop: JSAtom,
+    val: JSValue,
+) -> ::std::os::raw::c_int {
     JS_SetProperty_real(ctx, this_obj, prop, val)
 }
 
 /// create a new Function based on a JSCFunction
-pub unsafe fn JS_NewCFunction(ctx: *mut JSContext, func: *mut JSCFunction, name: *const ::std::os::raw::c_char,length: ::std::os::raw::c_int) -> JSValue {
+pub unsafe fn JS_NewCFunction(
+    ctx: *mut JSContext,
+    func: *mut JSCFunction,
+    name: *const ::std::os::raw::c_char,
+    length: ::std::os::raw::c_int,
+) -> JSValue {
     JS_NewCFunction_real(ctx, func, name, length)
 }
 
 /// create a new Function based on a JSCFunction
-pub unsafe fn JS_NewCFunctionMagic(ctx: *mut JSContext, func: *mut JSCFunctionMagic, name: *const ::std::os::raw::c_char, length: ::std::os::raw::c_int, cproto: JSCFunctionEnum, magic: ::std::os::raw::c_int) -> JSValue {
+pub unsafe fn JS_NewCFunctionMagic(
+    ctx: *mut JSContext,
+    func: *mut JSCFunctionMagic,
+    name: *const ::std::os::raw::c_char,
+    length: ::std::os::raw::c_int,
+    cproto: JSCFunctionEnum,
+    magic: ::std::os::raw::c_int,
+) -> JSValue {
     JS_NewCFunctionMagic_real(ctx, func, name, length, cproto, magic)
 }

serde/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "quick-js-serde"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+libquickjs-sys = { path = "../libquickjs-sys" }
+
+serde = "1"
+thiserror = "1"
+
+[dev-dependencies]
+quick-js = { path = "..", features = ["serde"] }
+serde = { version = "1", features = ["derive"] }

serde/src/context.rs

@@ -0,0 +1,34 @@
+use libquickjs_sys::JSContext;
+
+pub struct Context {
+    context: *const JSContext,
+    should_drop: bool,
+}
+
+impl Context {
+    pub fn new(context: *mut JSContext) -> Self {
+        Self {
+            context,
+            should_drop: true,
+        }
+    }
+
+    pub fn new_without_drop(context: *mut JSContext) -> Self {
+        Self {
+            context,
+            should_drop: false,
+        }
+    }
+
+    pub(crate) fn as_mut_ptr(&mut self) -> *mut JSContext {
+        self.context as *mut _
+    }
+}
+
+impl Drop for Context {
+    fn drop(&mut self) {
+        if self.should_drop {
+            unsafe { libquickjs_sys::JS_FreeContext(self.context as *mut _) };
+        }
+    }
+}

serde/src/errors.rs

@@ -0,0 +1,119 @@
+use std::ffi::CStr;
+use std::str::Utf8Error;
+
+use libquickjs_sys::{
+    JSContext, JSValue, JS_FreeCString, JS_FreeValue, JS_GetException, JS_IsException, JS_IsNull,
+    JS_IsString, JS_ToCStringLen2, JS_ToString,
+};
+use thiserror::Error;
+
+#[derive(Debug, Clone, Error)]
+pub enum Internal {
+    #[error("Unexpected null pointer")]
+    UnexpectedNullPointer,
+    #[error("Unexpected null value")]
+    UnexpectedNullValue,
+    #[error("Expected string")]
+    ExpectedString,
+    #[error("Invalid UTF-8")]
+    InvalidUtf8(#[from] Utf8Error),
+    #[error("Nul byte found in string")]
+    NulError(#[from] std::ffi::NulError),
+}
+
+unsafe fn get_string(context: *mut JSContext, value: JSValue) -> Result<String, Internal> {
+    if !JS_IsString(value) {
+        return Err(Internal::ExpectedString);
+    }
+
+    // convert to a rust string
+    let ptr = JS_ToCStringLen2(context, std::ptr::null_mut(), value, 0);
+
+    if ptr.is_null() {
+        return Err(Internal::UnexpectedNullPointer);
+    }
+
+    let c_str = CStr::from_ptr(ptr);
+
+    let string = c_str.to_str()?.to_string();
+
+    // Free the C string
+    JS_FreeCString(context, ptr);
+
+    Ok(string)
+}
+
+unsafe fn exception_to_string(
+    context: *mut JSContext,
+    exception: JSValue,
+) -> Result<String, Internal> {
+    if JS_IsNull(exception) {
+        return Err(Internal::UnexpectedNullValue);
+    }
+
+    let exception = if JS_IsString(exception) {
+        exception
+    } else {
+        JS_ToString(context, exception)
+    };
+
+    get_string(context, exception)
+}
+
+#[derive(Debug, Clone, Error)]
+pub enum SerializationError {
+    #[error("Out of memory")]
+    OutOfMemory,
+    #[error("Internal error: {0}")]
+    Internal(#[from] Internal),
+    #[error("Unknown error: {0}")]
+    Unknown(String),
+    #[error("Expected call to `serialize_key` before `serialize_value`")]
+    MissingKey,
+    #[error("Expected call times of calls to `serialize_key` and `serialize_value` to be equal")]
+    MissingValue,
+    #[error("Expected either a string or a number as a key")]
+    InvalidKey,
+    #[error("The serializer is in an invalid state")]
+    InvalidState,
+    #[error("The number is too large to be represented")]
+    IntTooLarge,
+}
+
+impl SerializationError {
+    pub fn from_exception(context: *mut JSContext) -> Self {
+        // https://bellard.org/quickjs/quickjs.html#Exceptions 3.4.4
+        let exception = unsafe { JS_GetException(context) };
+
+        let value = unsafe { exception_to_string(context, exception) };
+
+        match value {
+            Ok(value) => {
+                if value.contains("out of memory") {
+                    Self::OutOfMemory
+                } else {
+                    Self::Unknown(value)
+                }
+            }
+            Err(err) => err.into(),
+        }
+    }
+
+    pub fn try_from_value(context: *mut JSContext, value: JSValue) -> Result<JSValue, Self> {
+        if unsafe { JS_IsException(value) } {
+            // we're for sure an error, we just don't know which one
+            // TODO: do we need to free here?
+            unsafe { JS_FreeValue(context, value) }
+
+            Err(Self::from_exception(context))
+        } else {
+            Ok(value)
+        }
+    }
+}
+
+impl serde::ser::Error for SerializationError {
+    fn custom<T: std::fmt::Display>(msg: T) -> Self {
+        Self::Unknown(msg.to_string())
+    }
+}

serde/src/lib.rs

@@ -0,0 +1,19 @@
+mod context;
+mod errors;
+mod ser;
+
+pub use context::Context;
+use libquickjs_sys::JSValue;
+use serde::Serialize;
+
+pub fn serialize<T: ?Sized>(
+    value: &T,
+    context: &mut Context,
+) -> Result<JSValue, errors::SerializationError>
+where
+    T: Serialize,
+{
+    let serializer = ser::Serializer::new(context);
+
+    value.serialize(serializer)
+}