2019-05-26 09:30:33 -05:00

885 lines
31 KiB
Rust

use crate::descriptor::{Descriptor, Function};
use crate::js::Context;
use failure::{bail, Error};
pub struct JsArgument {
pub optional: bool,
pub name: String,
pub type_: String,
}
impl JsArgument {
fn required(name: String, type_: String) -> Self {
Self { optional: false, name, type_ }
}
fn optional(name: String, type_: String) -> Self {
Self { optional: true, name, type_ }
}
}
/// Helper struct for manufacturing a shim in JS used to translate JS types to
/// Rust, aka pass from JS back into Rust
pub struct Js2Rust<'a, 'b: 'a> {
cx: &'a mut Context<'b>,
/// Arguments passed to the invocation of the wasm function, aka things that
/// are only numbers.
rust_arguments: Vec<String>,
/// Arguments and their types to the JS shim.
pub js_arguments: Vec<JsArgument>,
/// Conversions that happen before we invoke the wasm function, such as
/// converting a string to a ptr/length pair.
prelude: String,
/// "Destructors" or cleanup that must happen after the wasm function
/// finishes. This is scheduled in a `finally` block.
finally: String,
/// Index of the next argument for unique name generation purposes.
arg_idx: usize,
/// Typescript expression representing the type of the return value of this
/// function.
ret_ty: String,
/// Expression used to generate the return value. The string "RET" in this
/// expression is replaced with the actual wasm invocation eventually.
ret_expr: String,
/// Name of the JS shim/function that we're generating, primarily for
/// TypeScript right now.
js_name: String,
/// whether or not this generated function body will act like a constructor,
/// meaning it doesn't actually return something but rather assigns to
/// `this`
///
/// The string value here is the class that this should be a constructor
/// for.
constructor: Option<String>,
/// metadata for anyref transformations
anyref_args: Vec<(usize, bool)>,
ret_anyref: bool,
}
pub enum ExportedShim<'a> {
Named(&'a str),
TableElement(&'a mut u32),
}
impl<'a, 'b> Js2Rust<'a, 'b> {
pub fn new(js_name: &str, cx: &'a mut Context<'b>) -> Js2Rust<'a, 'b> {
Js2Rust {
cx,
js_name: js_name.to_string(),
rust_arguments: Vec::new(),
js_arguments: Vec::new(),
prelude: String::new(),
finally: String::new(),
arg_idx: 0,
ret_ty: String::new(),
ret_expr: String::new(),
constructor: None,
anyref_args: Vec::new(),
ret_anyref: false,
}
}
/// Generates all bindings necessary for the signature in `Function`,
/// creating necessary argument conversions and return value processing.
pub fn process<'c, I>(
&mut self,
function: &Function,
opt_arg_names: I,
) -> Result<&mut Self, Error>
where
I: Into<Option<&'c Vec<String>>>,
{
if let Some(arg_names) = opt_arg_names.into() {
for (arg, arg_name) in function.arguments.iter().zip(arg_names) {
self.argument(arg, arg_name.as_str())?;
}
} else {
for arg in function.arguments.iter() {
self.argument(arg, None)?;
}
}
self.ret(&function.ret)?;
Ok(self)
}
pub fn constructor(&mut self, class: Option<&str>) -> &mut Self {
self.constructor = class.map(|s| s.to_string());
self
}
/// Flag this shim as a method call into Rust, so the first Rust argument
/// passed should be `this.ptr`.
pub fn method(&mut self, consumed: bool) -> &mut Self {
if self.cx.config.debug {
self.prelude(
"if (this.ptr === 0) {
throw new Error('Attempt to use a moved value');
}",
);
}
if consumed {
self.prelude(
"\
const ptr = this.ptr;\n\
this.ptr = 0;\n\
",
);
self.rust_arguments.insert(0, "ptr".to_string());
} else {
self.rust_arguments.insert(0, "this.ptr".to_string());
}
self
}
/// Add extra processing to the prelude of this shim.
pub fn prelude(&mut self, s: &str) -> &mut Self {
for line in s.lines() {
self.prelude.push_str(line);
self.prelude.push_str("\n");
}
self
}
/// Add extra processing to the finally block of this shim.
pub fn finally(&mut self, s: &str) -> &mut Self {
for line in s.lines() {
self.finally.push_str(line);
self.finally.push_str("\n");
}
self
}
/// Add an Rust argument to be passed manually.
pub fn rust_argument(&mut self, s: &str) -> &mut Self {
self.rust_arguments.push(s.to_string());
self
}
fn abi_arg(&mut self, opt_arg_name: Option<&str>) -> String {
let ret = if let Some(x) = opt_arg_name {
x.into()
} else {
format!("arg{}", self.arg_idx)
};
self.arg_idx += 1;
ret
}
pub fn argument<'c, I>(&mut self, arg: &Descriptor, opt_arg_name: I) -> Result<&mut Self, Error>
where
I: Into<Option<&'c str>>,
{
let i = self.arg_idx;
let name = self.abi_arg(opt_arg_name.into());
let (arg, optional) = match arg {
Descriptor::Option(t) => (&**t, true),
_ => (arg, false),
};
if let Some(kind) = arg.vector_kind() {
self.js_arguments
.push(JsArgument::required(name.clone(), kind.js_ty().to_string()));
let func = self.cx.pass_to_wasm_function(kind)?;
let val = if optional {
self.cx.expose_is_like_none();
format!("isLikeNone({}) ? [0, 0] : {}({})", name, func, name)
} else {
format!("{}({})", func, name)
};
self.prelude(&format!(
"const ptr{i} = {val};\nconst len{i} = WASM_VECTOR_LEN;",
i = i,
val = val,
));
if arg.is_by_ref() || arg.is_clamped_by_ref() {
if optional {
bail!("optional slices aren't currently supported");
}
if arg.is_mut_ref() {
let get = self.cx.memview_function(kind);
self.finally(&format!(
"\
{arg}.set({get}().subarray(\
ptr{i} / {size}, \
ptr{i} / {size} + len{i}\
));\n\
",
i = i,
arg = name,
get = get,
size = kind.size()
));
}
self.finally(&format!(
"\
wasm.__wbindgen_free(ptr{i}, len{i} * {size});\n\
",
i = i,
size = kind.size()
));
self.cx.require_internal_export("__wbindgen_free")?;
}
self.rust_arguments.push(format!("ptr{}", i));
self.rust_arguments.push(format!("len{}", i));
return Ok(self);
}
if arg.is_anyref() {
self.js_arguments.push(JsArgument::required(name.clone(), "any".to_string()));
if self.cx.config.anyref {
if optional {
self.cx.expose_add_to_anyref_table()?;
self.cx.expose_is_like_none();
self.rust_arguments
.push(format!("isLikeNone({0}) ? 0 : addToAnyrefTable({0})", name));
} else {
self.anyref_args.push((self.rust_arguments.len(), true));
self.rust_arguments.push(name);
}
} else {
self.cx.expose_add_heap_object();
if optional {
self.cx.expose_is_like_none();
self.rust_arguments
.push(format!("isLikeNone({0}) ? 0 : addHeapObject({0})", name));
} else {
self.rust_arguments.push(format!("addHeapObject({})", name));
}
}
return Ok(self);
}
if optional {
self.cx.expose_is_like_none();
if arg.is_wasm_native() {
self.js_arguments
.push(JsArgument::optional(name.clone(), "number".to_string()));
if self.cx.config.debug {
self.cx.expose_assert_num();
self.prelude(&format!(
"
if (!isLikeNone({0})) {{
_assertNum({0});
}}
",
name
));
}
self.rust_arguments.push(format!("!isLikeNone({0})", name));
self.rust_arguments
.push(format!("isLikeNone({0}) ? 0 : {0}", name));
return Ok(self);
}
if arg.is_abi_as_u32() {
self.js_arguments
.push(JsArgument::optional(name.clone(), "number".to_string()));
if self.cx.config.debug {
self.cx.expose_assert_num();
self.prelude(&format!(
"
if (!isLikeNone({0})) {{
_assertNum({0});
}}
",
name
));
}
self.rust_arguments
.push(format!("isLikeNone({0}) ? 0xFFFFFF : {0}", name));
return Ok(self);
}
if let Some(signed) = arg.get_64() {
let f = if signed {
self.cx.expose_int64_cvt_shim()
} else {
self.cx.expose_uint64_cvt_shim()
};
self.cx.expose_uint32_memory();
self.js_arguments
.push(JsArgument::optional(name.clone(), "BigInt".to_string()));
self.prelude(&format!(
"
{f}[0] = isLikeNone({name}) ? BigInt(0) : {name};
const low{i} = isLikeNone({name}) ? 0 : u32CvtShim[0];
const high{i} = isLikeNone({name}) ? 0 : u32CvtShim[1];
",
i = i,
f = f,
name = name,
));
self.rust_arguments.push(format!("!isLikeNone({})", name));
self.rust_arguments.push(format!("0"));
self.rust_arguments.push(format!("low{}", i));
self.rust_arguments.push(format!("high{}", i));
return Ok(self);
}
match *arg {
Descriptor::Boolean => {
self.js_arguments
.push(JsArgument::optional(name.clone(), "boolean".to_string()));
if self.cx.config.debug {
self.cx.expose_assert_bool();
self.prelude(&format!(
"
if (!isLikeNone({0})) {{
_assertBoolean({0});
}}
",
name,
));
}
self.rust_arguments
.push(format!("isLikeNone({0}) ? 0xFFFFFF : {0} ? 1 : 0", name));
}
Descriptor::Char => {
self.js_arguments
.push(JsArgument::optional(name.clone(), "string".to_string()));
self.rust_arguments.push(format!(
"isLikeNone({0}) ? 0xFFFFFF : {0}.codePointAt(0)",
name
));
}
Descriptor::Enum { hole } => {
self.js_arguments
.push(JsArgument::optional(name.clone(), "number".to_string()));
self.rust_arguments
.push(format!("isLikeNone({0}) ? {1} : {0}", name, hole));
}
Descriptor::RustStruct(ref s) => {
self.js_arguments
.push(JsArgument::optional(name.clone(), s.to_string()));
self.prelude(&format!("let ptr{} = 0;", i));
self.prelude(&format!("if (!isLikeNone({0})) {{", name));
self.assert_class(&name, s);
self.assert_not_moved(&name);
self.prelude(&format!("ptr{} = {}.ptr;", i, name));
self.prelude(&format!("{}.ptr = 0;", name));
self.prelude("}");
self.rust_arguments.push(format!("ptr{}", i));
}
_ => bail!(
"unsupported optional argument type for calling Rust function from JS: {:?}",
arg
),
}
return Ok(self);
}
if let Some(s) = arg.rust_struct() {
self.js_arguments.push(JsArgument::required(name.clone(), s.to_string()));
self.assert_class(&name, s);
self.assert_not_moved(&name);
if arg.is_by_ref() {
self.rust_arguments.push(format!("{}.ptr", name));
} else {
self.prelude(&format!("const ptr{} = {}.ptr;", i, name));
self.prelude(&format!("{}.ptr = 0;", name));
self.rust_arguments.push(format!("ptr{}", i));
}
return Ok(self);
}
if arg.number().is_some() {
self.js_arguments.push(JsArgument::required(name.clone(), "number".to_string()));
if self.cx.config.debug {
self.cx.expose_assert_num();
self.prelude(&format!("_assertNum({});", name));
}
self.rust_arguments.push(name);
return Ok(self);
}
if let Some(signed) = arg.get_64() {
let f = if signed {
self.cx.expose_int64_cvt_shim()
} else {
self.cx.expose_uint64_cvt_shim()
};
self.cx.expose_uint32_memory();
self.js_arguments.push(JsArgument::required(name.clone(), "BigInt".to_string()));
self.prelude(&format!(
"
{f}[0] = {name};
const low{i} = u32CvtShim[0];
const high{i} = u32CvtShim[1];
",
i = i,
f = f,
name = name,
));
self.rust_arguments.push(format!("low{}", i));
self.rust_arguments.push(format!("high{}", i));
return Ok(self);
}
if arg.is_ref_anyref() {
self.js_arguments.push(JsArgument::required(name.clone(), "any".to_string()));
if self.cx.config.anyref {
self.anyref_args.push((self.rust_arguments.len(), false));
self.rust_arguments.push(name);
} else {
// the "stack-ful" nature means that we're always popping from the
// stack, and make sure that we actually clear our reference to
// allow stale values to get GC'd
self.cx.expose_borrowed_objects();
self.cx.expose_global_stack_pointer();
self.finally("heap[stack_pointer++] = undefined;");
self.rust_arguments
.push(format!("addBorrowedObject({})", name));
}
return Ok(self);
}
match *arg {
Descriptor::Boolean => {
self.js_arguments
.push(JsArgument::required(name.clone(), "boolean".to_string()));
if self.cx.config.debug {
self.cx.expose_assert_bool();
self.prelude(&format!(
"\
_assertBoolean({name});\n\
",
name = name
));
}
self.rust_arguments.push(format!("{}", name));
}
Descriptor::Char => {
self.js_arguments.push(JsArgument::required(name.clone(), "string".to_string()));
self.rust_arguments.push(format!("{}.codePointAt(0)", name))
}
_ => bail!(
"unsupported argument type for calling Rust function from JS: {:?}",
arg
),
}
Ok(self)
}
pub fn ret(&mut self, ty: &Descriptor) -> Result<&mut Self, Error> {
if let Some(name) = ty.rust_struct() {
match &self.constructor {
Some(class) if class == name => {
self.ret_expr = format!("this.ptr = RET;");
if self.cx.config.weak_refs {
self.ret_expr.push_str(&format!(
"\
{}FinalizationGroup.register(this, this.ptr, this.ptr);
",
name
));
}
}
Some(class) => bail!("constructor for `{}` cannot return `{}`", class, name),
None => {
self.ret_ty = name.to_string();
self.cx.require_class_wrap(name);
self.ret_expr = format!("return {name}.__wrap(RET);", name = name);
}
}
return Ok(self);
}
if self.constructor.is_some() {
bail!("constructor functions must return a Rust structure")
}
if let Descriptor::Unit = ty {
self.ret_ty = "void".to_string();
self.ret_expr = format!("return RET;");
return Ok(self);
}
let (ty, optional) = match ty {
Descriptor::Option(t) => (&**t, true),
_ => (ty, false),
};
if let Some(ty) = ty.vector_kind() {
self.ret_ty = ty.js_ty().to_string();
let f = self.cx.expose_get_vector_from_wasm(ty)?;
self.cx.expose_global_argument_ptr()?;
self.cx.expose_uint32_memory();
self.cx.require_internal_export("__wbindgen_free")?;
self.prelude("const retptr = globalArgumentPtr();");
self.rust_arguments.insert(0, "retptr".to_string());
self.ret_expr = format!(
"\
RET;\n\
const mem = getUint32Memory();\n\
const rustptr = mem[retptr / 4];\n\
const rustlen = mem[retptr / 4 + 1];\n\
{guard}
const realRet = {}(rustptr, rustlen).slice();\n\
wasm.__wbindgen_free(rustptr, rustlen * {});\n\
return realRet;\n\
",
f,
ty.size(),
guard = if optional {
"if (rustptr === 0) return;"
} else {
""
},
);
return Ok(self);
}
// No need to worry about `optional` here, the abi representation means
// that `takeObject` will naturally pluck out `undefined`.
if ty.is_anyref() {
self.ret_ty = "any".to_string();
self.ret_expr = format!("return {};", self.cx.take_object("RET"));
self.ret_anyref = true;
return Ok(self);
}
if optional {
if ty.is_wasm_native() {
self.ret_ty = "number | undefined".to_string();
self.cx.expose_global_argument_ptr()?;
self.cx.expose_uint32_memory();
match ty {
Descriptor::I32 => self.cx.expose_int32_memory(),
Descriptor::U32 => (),
Descriptor::F32 => self.cx.expose_f32_memory(),
Descriptor::F64 => self.cx.expose_f64_memory(),
_ => (),
};
self.prelude("const retptr = globalArgumentPtr();");
self.rust_arguments.insert(0, "retptr".to_string());
self.ret_expr = format!(
"
RET;
const present = getUint32Memory()[retptr / 4];
const value = {mem}[retptr / {size} + 1];
return present === 0 ? undefined : value;
",
size = match ty {
Descriptor::I32 => 4,
Descriptor::U32 => 4,
Descriptor::F32 => 4,
Descriptor::F64 => 8,
_ => unreachable!(),
},
mem = match ty {
Descriptor::I32 => "getInt32Memory()",
Descriptor::U32 => "getUint32Memory()",
Descriptor::F32 => "getFloat32Memory()",
Descriptor::F64 => "getFloat64Memory()",
_ => unreachable!(),
}
);
return Ok(self);
}
if ty.is_abi_as_u32() {
self.ret_ty = "number | undefined".to_string();
self.ret_expr = "
const ret = RET;
return ret === 0xFFFFFF ? undefined : ret;
"
.to_string();
return Ok(self);
}
if let Some(signed) = ty.get_64() {
self.ret_ty = "BigInt | undefined".to_string();
self.cx.expose_global_argument_ptr()?;
let f = if signed {
self.cx.expose_int64_memory();
"getInt64Memory"
} else {
self.cx.expose_uint64_memory();
"getUint64Memory"
};
self.prelude("const retptr = globalArgumentPtr();");
self.rust_arguments.insert(0, "retptr".to_string());
self.ret_expr = format!(
"
RET;
const present = getUint32Memory()[retptr / 4];
const value = {}()[retptr / 8 + 1];
return present === 0 ? undefined : value;
",
f
);
return Ok(self);
}
match *ty {
Descriptor::Boolean => {
self.ret_ty = "boolean | undefined".to_string();
self.ret_expr = "
const ret = RET;
return ret === 0xFFFFFF ? undefined : ret !== 0;
"
.to_string();
return Ok(self);
}
Descriptor::Char => {
self.ret_ty = "string | undefined".to_string();
self.ret_expr = "
const ret = RET;
return ret === 0xFFFFFF ? undefined : String.fromCodePoint(ret);
"
.to_string();
return Ok(self);
}
Descriptor::Enum { hole } => {
self.ret_ty = "number | undefined".to_string();
self.ret_expr = format!(
"
const ret = RET;
return ret === {} ? undefined : ret;
",
hole
);
return Ok(self);
}
Descriptor::RustStruct(ref name) => {
self.ret_ty = format!("{} | undefined", name);
self.cx.require_class_wrap(name);
self.ret_expr = format!(
"
const ptr = RET;
return ptr === 0 ? undefined : {}.__wrap(ptr);
",
name,
);
return Ok(self);
}
_ => bail!(
"unsupported optional return type for calling Rust function from JS: {:?}",
ty
),
};
}
if ty.is_ref_anyref() {
self.ret_ty = "any".to_string();
self.cx.expose_get_object();
self.ret_expr = format!("return getObject(RET);");
return Ok(self);
}
if ty.is_by_ref() {
bail!("cannot return references from Rust to JS yet")
}
if let Some(name) = ty.rust_struct() {
self.ret_ty = name.to_string();
self.cx.require_class_wrap(name);
self.ret_expr = format!("return {name}.__wrap(RET);", name = name);
return Ok(self);
}
if let Some(num) = ty.number() {
self.ret_ty = "number".to_string();
if num.is_u32() {
self.ret_expr = format!("return RET >>> 0;");
} else {
self.ret_expr = format!("return RET;");
}
return Ok(self);
}
if let Some(signed) = ty.get_64() {
self.ret_ty = "BigInt".to_string();
self.cx.expose_global_argument_ptr()?;
let f = if signed {
self.cx.expose_int64_memory();
"getInt64Memory"
} else {
self.cx.expose_uint64_memory();
"getUint64Memory"
};
self.prelude("const retptr = globalArgumentPtr();");
self.rust_arguments.insert(0, "retptr".to_string());
self.ret_expr = format!(
"\
RET;\n\
return {}()[retptr / 8];\n\
",
f
);
return Ok(self);
}
match *ty {
Descriptor::Boolean => {
self.ret_ty = "boolean".to_string();
self.ret_expr = format!("return (RET) !== 0;");
}
Descriptor::Char => {
self.ret_ty = "string".to_string();
self.ret_expr = format!("return String.fromCodePoint(RET);")
}
_ => bail!(
"unsupported return type for calling Rust function from JS: {:?}",
ty
),
}
Ok(self)
}
pub fn js_doc_comments(&self) -> String {
let mut ret: String = self
.js_arguments
.iter()
.map(|a| if a.optional {
format!("@param {{{} | undefined}} {}\n", a.type_, a.name)
} else {
format!("@param {{{}}} {}\n", a.type_, a.name)
})
.collect();
ret.push_str(&format!("@returns {{{}}}", self.ret_ty));
ret
}
/// Generate the actual function.
///
/// The `prefix` specified is typically the string "function" but may be
/// different for classes. The `invoc` is the function expression that we're
/// invoking, like `wasm.bar` or `this.f`.
///
/// Returns two strings, the first of which is the JS expression for the
/// generated function shim and the second is a TypeScript signature of the
/// JS expression.
pub fn finish(
&mut self,
prefix: &str,
invoc: &str,
exported_shim: ExportedShim,
) -> (String, String, String) {
let js_args = self
.js_arguments
.iter()
.map(|s| &s.name[..])
.collect::<Vec<_>>()
.join(", ");
let mut js = format!("{}({}) {{\n", prefix, js_args);
js.push_str(&self.prelude);
let rust_args = self.rust_arguments.join(", ");
let invoc = self
.ret_expr
.replace("RET", &format!("{}({})", invoc, rust_args));
let invoc = if self.finally.len() == 0 {
invoc
} else {
format!(
"\
try {{\n\
{}
\n}} finally {{\n\
{}
}}\n\
",
&invoc, &self.finally,
)
};
js.push_str(&invoc);
js.push_str("\n}");
// Determine TS parameter list
let mut omittable = true;
let mut ts_args = Vec::with_capacity(self.js_arguments.len());
for arg in self.js_arguments.iter().rev() {
// In TypeScript, we can mark optional parameters as omittable
// using the `?` suffix, but only if they're not followed by
// non-omittable parameters. Therefore iterate the parameter list
// in reverse and stop using the `?` suffix for optional params as
// soon as a non-optional parameter is encountered.
if arg.optional {
if omittable {
ts_args.push(format!("{}?: {}", arg.name, arg.type_));
} else {
ts_args.push(format!("{}: {} | undefined", arg.name, arg.type_));
}
} else {
omittable = false;
ts_args.push(format!("{}: {}", arg.name, arg.type_));
}
}
ts_args.reverse();
let ts_args = ts_args.join(", ");
let mut ts = if prefix.is_empty() {
format!("{}({})", self.js_name, ts_args)
} else {
format!("{} {}({})", prefix, self.js_name, ts_args)
};
if self.constructor.is_none() {
ts.push_str(": ");
ts.push_str(&self.ret_ty);
}
ts.push(';');
if self.ret_anyref || self.anyref_args.len() > 0 {
match exported_shim {
ExportedShim::Named(name) => {
self.cx
.anyref
.export_xform(name, &self.anyref_args, self.ret_anyref);
}
ExportedShim::TableElement(idx) => {
*idx = self.cx.anyref.table_element_xform(
*idx,
&self.anyref_args,
self.ret_anyref,
);
}
}
}
(js, ts, self.js_doc_comments())
}
fn assert_class(&mut self, arg: &str, class: &str) {
if !self.cx.config.debug {
return;
}
self.cx.expose_assert_class();
self.prelude(&format!("_assertClass({}, {});", arg, class));
}
fn assert_not_moved(&mut self, arg: &str) {
if !self.cx.config.debug {
return;
}
self.prelude(&format!(
"\
if ({0}.ptr === 0) {{
throw new Error('Attempt to use a moved value');
}}
",
arg,
));
}
}