1 files changed, 302 insertions, 0 deletions
diff --git a/toolkit/components/uniffi-bindgen-gecko-js/src/render/js.rs b/toolkit/components/uniffi-bindgen-gecko-js/src/render/js.rs
new file mode 100644
index 0000000000..728be7db96
--- /dev/null
+++ b/toolkit/components/uniffi-bindgen-gecko-js/src/render/js.rs
@@ -0,0 +1,302 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+License, v. 2.0. If a copy of the MPL was not distributed with this
+* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use super::shared::*;
+use crate::{CallbackIds, Config, FunctionIds, ObjectIds};
+use askama::Template;
+use extend::ext;
+use heck::{ToLowerCamelCase, ToShoutySnakeCase, ToUpperCamelCase};
+use uniffi_bindgen::interface::{
+    Argument, CallbackInterface, ComponentInterface, Constructor, Enum, Error, Field, Function,
+    Literal, Method, Object, Radix, Record, Type,
+};
+
+fn arg_names(args: &[&Argument]) -> String {
+    args.iter()
+        .map(|arg| {
+            if let Some(default_value) = arg.default_value() {
+                format!("{} = {}", arg.nm(), default_value.render())
+            } else {
+                arg.nm()
+            }
+        })
+        .collect::<Vec<String>>()
+        .join(",")
+}
+
+fn render_enum_literal(typ: &Type, variant_name: &str) -> String {
+    if let Type::Enum(enum_name) = typ {
+        // TODO: This does not support complex enum literals yet.
+        return format!(
+            "{}.{}",
+            enum_name.to_upper_camel_case(),
+            variant_name.to_shouty_snake_case()
+        );
+    } else {
+        panic!("Rendering an enum literal on a type that is not an enum")
+    }
+}
+
+#[derive(Template)]
+#[template(path = "js/wrapper.sys.mjs", escape = "none")]
+pub struct JSBindingsTemplate<'a> {
+    pub ci: &'a ComponentInterface,
+    pub config: &'a Config,
+    pub function_ids: &'a FunctionIds<'a>,
+    pub object_ids: &'a ObjectIds<'a>,
+    pub callback_ids: &'a CallbackIds<'a>,
+}
+
+impl<'a> JSBindingsTemplate<'a> {
+    pub fn js_module_name(&self) -> String {
+        self.js_module_name_for_ci_namespace(self.ci.namespace())
+    }
+
+    fn external_type_module(&self, crate_name: &str) -> String {
+        format!(
+            "resource://gre/modules/{}",
+            self.js_module_name_for_crate_name(crate_name),
+        )
+    }
+
+    // TODO: Once https://phabricator.services.mozilla.com/D156116 is merged maybe the next two
+    // functions should use a map from the config file
+
+    fn js_module_name_for_ci_namespace(&self, namespace: &str) -> String {
+        // The plain namespace name is a bit too generic as a module name for m-c, so we
+        // prefix it with "Rust". Later we'll probably allow this to be customized.
+        format!("Rust{}.sys.mjs", namespace.to_upper_camel_case())
+    }
+
+    fn js_module_name_for_crate_name(&self, crate_name: &str) -> String {
+        let namespace = match crate_name {
+            "uniffi_geometry" => "geometry",
+            s => s,
+        };
+        self.js_module_name_for_ci_namespace(namespace)
+    }
+}
+
+// Define extension traits with methods used in our template code
+
+#[ext(name=LiteralJSExt)]
+pub impl Literal {
+    fn render(&self) -> String {
+        match self {
+            Literal::Boolean(inner) => inner.to_string(),
+            Literal::String(inner) => format!("\"{}\"", inner),
+            Literal::UInt(num, radix, _) => format!("{}", radix.render_num(num)),
+            Literal::Int(num, radix, _) => format!("{}", radix.render_num(num)),
+            Literal::Float(num, _) => num.clone(),
+            Literal::Enum(name, typ) => render_enum_literal(typ, name),
+            Literal::EmptyMap => "{}".to_string(),
+            Literal::EmptySequence => "[]".to_string(),
+            Literal::Null => "null".to_string(),
+        }
+    }
+}
+
+#[ext(name=RadixJSExt)]
+pub impl Radix {
+    fn render_num(
+        &self,
+        num: impl std::fmt::Display + std::fmt::LowerHex + std::fmt::Octal,
+    ) -> String {
+        match self {
+            Radix::Decimal => format!("{}", num),
+            Radix::Hexadecimal => format!("{:#x}", num),
+            Radix::Octal => format!("{:#o}", num),
+        }
+    }
+}
+
+#[ext(name=RecordJSExt)]
+pub impl Record {
+    fn nm(&self) -> String {
+        self.name().to_upper_camel_case()
+    }
+
+    fn constructor_field_list(&self) -> String {
+        self.fields()
+            .iter()
+            .map(|field| {
+                if let Some(default_value) = field.default_value() {
+                    format!("{} = {}", field.nm(), default_value.render())
+                } else {
+                    field.nm()
+                }
+            })
+            .collect::<Vec<String>>()
+            .join(",")
+    }
+}
+
+#[ext(name=CallbackInterfaceJSExt)]
+pub impl CallbackInterface {
+    fn nm(&self) -> String {
+        self.name().to_upper_camel_case()
+    }
+
+    fn handler(&self) -> String {
+        format!("callbackHandler{}", self.nm())
+    }
+}
+
+#[ext(name=FieldJSExt)]
+pub impl Field {
+    fn nm(&self) -> String {
+        self.name().to_lower_camel_case()
+    }
+
+    fn lower_fn(&self) -> String {
+        self.type_().lower_fn()
+    }
+
+    fn lift_fn(&self) -> String {
+        self.type_().lift_fn()
+    }
+
+    fn write_datastream_fn(&self) -> String {
+        self.type_().write_datastream_fn()
+    }
+
+    fn read_datastream_fn(&self) -> String {
+        self.type_().read_datastream_fn()
+    }
+
+    fn compute_size_fn(&self) -> String {
+        self.type_().compute_size_fn()
+    }
+
+    fn ffi_converter(&self) -> String {
+        self.type_().ffi_converter()
+    }
+}
+
+#[ext(name=ArgumentJSExt)]
+pub impl Argument {
+    fn nm(&self) -> String {
+        self.name().to_lower_camel_case()
+    }
+
+    fn lower_fn(&self) -> String {
+        self.type_().lower_fn()
+    }
+
+    fn lift_fn(&self) -> String {
+        self.type_().lift_fn()
+    }
+
+    fn write_datastream_fn(&self) -> String {
+        self.type_().write_datastream_fn()
+    }
+
+    fn read_datastream_fn(&self) -> String {
+        self.type_().read_datastream_fn()
+    }
+
+    fn compute_size_fn(&self) -> String {
+        self.type_().compute_size_fn()
+    }
+
+    fn ffi_converter(&self) -> String {
+        self.type_().ffi_converter()
+    }
+}
+
+#[ext(name=TypeJSExt)]
+pub impl Type {
+    // Render an expression to check if two instances of this type are equal
+    fn equals(&self, first: &str, second: &str) -> String {
+        match self {
+            Type::Record(_) => format!("{}.equals({})", first, second),
+            _ => format!("{} == {}", first, second),
+        }
+    }
+
+    fn lower_fn(&self) -> String {
+        format!("{}.lower", self.ffi_converter())
+    }
+
+    fn lift_fn(&self) -> String {
+        format!("{}.lift", self.ffi_converter())
+    }
+
+    fn write_datastream_fn(&self) -> String {
+        format!("{}.write", self.ffi_converter())
+    }
+
+    fn read_datastream_fn(&self) -> String {
+        format!("{}.read", self.ffi_converter())
+    }
+
+    fn compute_size_fn(&self) -> String {
+        format!("{}.computeSize", self.ffi_converter())
+    }
+
+    fn ffi_converter(&self) -> String {
+        format!(
+            "FfiConverter{}",
+            self.canonical_name().to_upper_camel_case()
+        )
+    }
+}
+
+#[ext(name=EnumJSExt)]
+pub impl Enum {
+    fn nm(&self) -> String {
+        self.name().to_upper_camel_case()
+    }
+}
+
+#[ext(name=FunctionJSExt)]
+pub impl Function {
+    fn arg_names(&self) -> String {
+        arg_names(self.arguments().as_slice())
+    }
+
+    fn nm(&self) -> String {
+        self.name().to_lower_camel_case()
+    }
+}
+
+#[ext(name=ErrorJSExt)]
+pub impl Error {
+    fn nm(&self) -> String {
+        self.name().to_upper_camel_case()
+    }
+}
+
+#[ext(name=ObjectJSExt)]
+pub impl Object {
+    fn nm(&self) -> String {
+        self.name().to_upper_camel_case()
+    }
+}
+
+#[ext(name=ConstructorJSExt)]
+pub impl Constructor {
+    fn nm(&self) -> String {
+        if self.is_primary_constructor() {
+            "init".to_string()
+        } else {
+            self.name().to_lower_camel_case()
+        }
+    }
+
+    fn arg_names(&self) -> String {
+        arg_names(&self.arguments().as_slice())
+    }
+}
+
+#[ext(name=MethodJSExt)]
+pub impl Method {
+    fn arg_names(&self) -> String {
+        arg_names(self.arguments().as_slice())
+    }
+
+    fn nm(&self) -> String {
+        self.name().to_lower_camel_case()
+    }
+}