webgl: Refactor implementation to move logic inside the DOM interfaces

This improves the encapsulation and consistency in our WebGL
implementation.

Also allows to implement new methods such as `getShaderSource()`.

It will also allow us to use `delete()` in the destructors of them (note
that we will want to keep track of them from the context).

components/script/dom/webglshader.rs

@@ -9,32 +9,120 @@ use dom::bindings::js::Root;
 use dom::bindings::utils::reflect_dom_object;
 use dom::webglobject::WebGLObject;
 
+use dom::bindings::codegen::Bindings::WebGLRenderingContextBinding::WebGLRenderingContextConstants as constants;
+
+use canvas_traits::{CanvasMsg, CanvasWebGLMsg, WebGLResult, WebGLError, WebGLShaderParameter};
+use std::sync::mpsc::{channel, Sender};
+use std::cell::Cell;
+use std::cell::RefCell;
+
 #[dom_struct]
 pub struct WebGLShader {
     webgl_object: WebGLObject,
     id: u32,
+    gl_type: u32,
+    // TODO(ecoal95): is RefCell ok?
+    source: RefCell<Option<String>>,
+    is_deleted: Cell<bool>,
+    // TODO(ecoal95): Valorate moving this to `WebGLObject`
+    renderer: Sender<CanvasMsg>,
 }
 
 impl WebGLShader {
-    fn new_inherited(id: u32) -> WebGLShader {
+    fn new_inherited(renderer: Sender<CanvasMsg>, id: u32, shader_type: u32) -> WebGLShader {
         WebGLShader {
             webgl_object: WebGLObject::new_inherited(),
             id: id,
+            gl_type: shader_type,
+            source: RefCell::new(None),
+            is_deleted: Cell::new(false),
+            renderer: renderer,
         }
     }
 
-    pub fn new(global: GlobalRef, id: u32) -> Root<WebGLShader> {
-        reflect_dom_object(box WebGLShader::new_inherited(id), global, WebGLShaderBinding::Wrap)
+    pub fn maybe_new(global: GlobalRef,
+                     renderer: Sender<CanvasMsg>,
+                     shader_type: u32) -> Option<Root<WebGLShader>> {
+        let (sender, receiver) = channel();
+        renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CreateShader(shader_type, sender))).unwrap();
+        receiver.recv().unwrap()
+            .map(|shader_id| WebGLShader::new(global, renderer, *shader_id, shader_type))
+    }
+
+    pub fn new(global: GlobalRef,
+               renderer: Sender<CanvasMsg>,
+               id: u32,
+               shader_type: u32) -> Root<WebGLShader> {
+        reflect_dom_object(
+            box WebGLShader::new_inherited(renderer, id, shader_type), global, WebGLShaderBinding::Wrap)
     }
 }
 
 pub trait WebGLShaderHelpers {
-    fn get_id(self) -> u32;
+    fn id(self) -> u32;
+    fn gl_type(self) -> u32;
+    fn compile(self);
+    fn delete(self);
+    fn info_log(self) -> Option<String>;
+    fn parameter(self, param_id: u32) -> WebGLResult<WebGLShaderParameter>;
+    fn source(self) -> Option<String>;
+    fn set_source(self, src: String);
 }
 
-impl<'a> WebGLShaderHelpers for &'a WebGLShader {
-    fn get_id(self) -> u32 {
+impl<'a> WebGLShaderHelpers for JSRef<'a, WebGLShader> {
+    fn id(self) -> u32 {
         self.id
     }
+
+    fn gl_type(self) -> u32 {
+        self.gl_type
+    }
+
+    // TODO(ecoal95): Validate shaders to be conforming to the WebGL spec
+    /// glCompileShader
+    fn compile(self) {
+        // NB(ecoal95): We intentionally don't check for source, we don't wan't
+        // to change gl error behavior
+        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::CompileShader(self.id))).unwrap()
+    }
+
+    /// Mark this shader as deleted (if it wasn't previously)
+    /// and delete it as if calling tr glDeleteShader.
+    fn delete(self) {
+        if !self.is_deleted.get() {
+            self.is_deleted.set(true);
+            self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::DeleteShader(self.id))).unwrap()
+        }
+    }
+
+    /// glGetShaderInfoLog
+    fn info_log(self) -> Option<String> {
+        let (sender, receiver) = channel();
+        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetShaderInfoLog(self.id, sender))).unwrap();
+        receiver.recv().unwrap()
+    }
+
+    /// glGetShaderParameter
+    fn parameter(self, param_id: u32) -> WebGLResult<WebGLShaderParameter> {
+        match param_id {
+            constants::SHADER_TYPE | constants::DELETE_STATUS | constants::COMPILE_STATUS => {},
+            _ => return Err(WebGLError::InvalidEnum),
+        }
+
+        let (sender, receiver) = channel();
+        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::GetShaderParameter(self.id, param_id, sender))).unwrap();
+        Ok(receiver.recv().unwrap())
+    }
+
+    /// Get the shader source
+    fn source(self) -> Option<String> {
+        (*self.source.borrow()).clone()
+    }
+
+    /// glShaderSource
+    fn set_source(self, source: String) {
+        *self.source.borrow_mut() = Some(source.clone());
+        self.renderer.send(CanvasMsg::WebGL(CanvasWebGLMsg::ShaderSource(self.id, source))).unwrap()
+    }
 }