Implement TextEncoder

Fixes #4768.

components/script/dom/textencoder.rs

@@ -0,0 +1,94 @@
+/* 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 dom::bindings::codegen::Bindings::TextEncoderBinding;
+use dom::bindings::codegen::Bindings::TextEncoderBinding::TextEncoderMethods;
+use dom::bindings::global::GlobalRef;
+use dom::bindings::error::Fallible;
+use dom::bindings::error::Error::IndexSize;
+use dom::bindings::js::{JSRef, Temporary};
+use dom::bindings::str::USVString;
+use dom::bindings::utils::{Reflector, reflect_dom_object};
+
+use util::str::DOMString;
+
+use std::borrow::ToOwned;
+use std::ascii::AsciiExt;
+use std::ptr;
+
+use encoding::types::EncodingRef;
+use encoding::{Encoding, EncoderTrap};
+use encoding::label::encoding_from_whatwg_label;
+
+use libc::uint8_t;
+use js::jsapi::{JSContext, JSObject};
+use js::jsfriendapi::bindgen::{JS_NewUint8Array, JS_GetUint8ArrayData};
+
+#[dom_struct]
+pub struct TextEncoder {
+    reflector_: Reflector,
+    encoding: DOMString,
+    encoder: EncodingRef,
+}
+
+impl TextEncoder {
+    fn new_inherited(encoding: DOMString, encoder: EncodingRef) -> TextEncoder {
+        TextEncoder {
+            reflector_: Reflector::new(),
+            encoding: encoding,
+            encoder: encoder,
+        }
+    }
+
+    pub fn new(global: GlobalRef, encoding: DOMString, encoder: EncodingRef) -> Temporary<TextEncoder> {
+        reflect_dom_object(box TextEncoder::new_inherited(encoding, encoder),
+                           global,
+                           TextEncoderBinding::Wrap)
+    }
+
+    // https://encoding.spec.whatwg.org/#dom-textencoder
+    pub fn Constructor(global: GlobalRef,
+                       label: DOMString) -> Fallible<Temporary<TextEncoder>> {
+        let encoding = match encoding_from_whatwg_label(label.trim().as_slice().to_ascii_lowercase().as_slice()) {
+            Some(enc) => enc,
+            None => {
+                debug!("Encoding Label Not Supported");
+                // TODO: should throw RangeError
+                return Err(IndexSize)
+            }
+        };
+
+        match encoding.name() {
+            "utf-8" | "utf-16be" | "utf-16le" => {
+                Ok(TextEncoder::new(global, encoding.name().to_owned(), encoding))
+            }
+            _ => {
+                debug!("Encoding Not UTF");
+                // TODO: should throw RangeError
+                Err(IndexSize)
+            }
+        }
+    }
+}
+
+impl<'a> TextEncoderMethods for JSRef<'a, TextEncoder> {
+    // https://encoding.spec.whatwg.org/#dom-textencoder-encoding
+    fn Encoding(self) -> DOMString {
+        self.encoding.clone()
+    }
+
+    // https://encoding.spec.whatwg.org/#dom-textencoder-encode
+    #[allow(unsafe_code)]
+    fn Encode(self, cx: *mut JSContext, input: USVString) -> *mut JSObject {
+        unsafe {
+            let output = self.encoder.encode(input.0.as_slice(), EncoderTrap::Strict).unwrap();
+            let length = output.len() as u32;
+            let js_object: *mut JSObject = JS_NewUint8Array(cx, length);
+
+            let js_object_data: *mut uint8_t = JS_GetUint8ArrayData(js_object, cx);
+            ptr::copy_nonoverlapping(js_object_data, output.as_ptr(), length as usize);
+            return js_object;
+        }
+    }
+}