auto merge of #3642 : Manishearth/servo/form-submit, r=jdm

This is missing a lot of parts, so it doesn't really make any real-world form submission work yet. It provides a skeleton on which the missing bits can be filled in.

What works:
 - `<input>` elements except for `type=file`
 - GET/POST methods
 - URLencoded `enctype`s (default)
 - Submission via `<form>.submit()` only

Stuff that needs to be done for most simple real-world cases to work: 
 - [Working text input](https://github.com/servo/servo/pull/3585)
 - Click handlers for `<submit>`
 - Possibly `<textarea>` support
 - Support for the other two enctypes (#3649)

Todo:
 - Correctly implement [planned navigation](https://html.spec.whatwg.org/multipage/forms.html#planned-navigation) using `TrustedFormAddress`  (#3648)
 - [Correctly implement form owners.](https://github.com/servo/servo/issues/3553) Requires html5ever and some discussion of the spec.
 - `<input type=file>` support
 - Image submit support
 - Browsing contexts/targets
 - Support for non-`<input>` controls
 - Validation (?)
 - Dirname (?)

1 files changed, 273 insertions, 6 deletions

diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 7b2ee466bab..03bd593cb64 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -2,19 +2,32 @@
  * 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::EventBinding::EventMethods;
+use dom::bindings::codegen::Bindings::EventTargetBinding::EventTargetMethods;
 use dom::bindings::codegen::Bindings::HTMLFormElementBinding;
 use dom::bindings::codegen::Bindings::HTMLFormElementBinding::HTMLFormElementMethods;
-use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLFormElementDerived};
+use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementMethods;
+use dom::bindings::codegen::InheritTypes::{ElementCast, EventTargetCast, HTMLFormElementDerived, NodeCast};
+use dom::bindings::codegen::InheritTypes::HTMLInputElementCast;
+use dom::bindings::global::Window;
 use dom::bindings::js::{JSRef, Temporary};
 use dom::bindings::utils::{Reflectable, Reflector};
-use dom::document::Document;
-use dom::element::{Element, AttributeHandlers, HTMLFormElementTypeId};
+use dom::document::{Document, DocumentHelpers};
+use dom::element::{Element, AttributeHandlers, HTMLFormElementTypeId, HTMLTextAreaElementTypeId, HTMLDataListElementTypeId};
+use dom::element::{HTMLInputElementTypeId, HTMLButtonElementTypeId, HTMLObjectElementTypeId, HTMLSelectElementTypeId};
+use dom::event::Event;
 use dom::eventtarget::{EventTarget, NodeTargetTypeId};
 use dom::htmlelement::HTMLElement;
-use dom::node::{Node, ElementNodeTypeId, window_from_node};
+use dom::htmlinputelement::HTMLInputElement;
+use dom::node::{Node, NodeHelpers, ElementNodeTypeId, document_from_node, window_from_node};
+use http::method::Post;
+use servo_msg::constellation_msg::LoadData;
 use servo_util::str::DOMString;
+use script_task::{ScriptChan, TriggerLoadMsg};
 use std::ascii::OwnedStrAsciiExt;
-
+use std::str::StrSlice;
+use url::UrlParser;
+use url::form_urlencoded::serialize;
 
 #[jstraceable]
 #[must_root]
@@ -52,7 +65,7 @@ impl<'a> HTMLFormElementMethods for JSRef<'a, HTMLFormElement> {
     // https://html.spec.whatwg.org/multipage/forms.html#dom-fs-action
     fn Action(self) -> DOMString {
         let element: JSRef<Element> = ElementCast::from_ref(self);
-        let url = element.get_url_attribute("src");
+        let url = element.get_url_attribute("action");
         match url.as_slice() {
             "" => {
                 let window = window_from_node(self).root();
@@ -135,6 +148,196 @@ impl<'a> HTMLFormElementMethods for JSRef<'a, HTMLFormElement> {
 
     // https://html.spec.whatwg.org/multipage/forms.html#dom-fs-target
     make_setter!(SetTarget, "target")
+
+    // https://html.spec.whatwg.org/multipage/forms.html#the-form-element:concept-form-submit
+    fn Submit(self) {
+        self.submit(true, FormElement(self));
+    }
+}
+
+pub trait HTMLFormElementHelpers {
+    // https://html.spec.whatwg.org/multipage/forms.html#concept-form-submit
+    fn submit(self, from_submit_method: bool, submitter: FormSubmitter);
+    // https://html.spec.whatwg.org/multipage/forms.html#constructing-the-form-data-set
+    fn get_form_dataset(self, submitter: Option<FormSubmitter>) -> Vec<FormDatum>;
+}
+
+impl<'a> HTMLFormElementHelpers for JSRef<'a, HTMLFormElement> {
+    fn submit(self, _from_submit_method: bool, submitter: FormSubmitter) {
+        // Step 1
+        let doc = document_from_node(self).root();
+        let win = window_from_node(self).root();
+        let base = doc.url();
+        // TODO: Handle browsing contexts
+        // TODO: Handle validation
+        let event = Event::new(&Window(*win),
+                               "submit".to_string(),
+                               true, true).root();
+        let target: JSRef<EventTarget> = EventTargetCast::from_ref(self);
+        target.DispatchEvent(*event).ok();
+        if event.DefaultPrevented() {
+            return;
+        }
+        // Step 6
+        let form_data = self.get_form_dataset(Some(submitter));
+        // Step 7-8
+        let mut action = submitter.action();
+        if action.is_empty() {
+            action = base.serialize();
+        }
+        // TODO: Resolve the url relative to the submitter element
+        // Step 10-15
+        let action_components = UrlParser::new().base_url(base).parse(action.as_slice()).unwrap_or(base.clone());
+        let _action = action_components.serialize();
+        let scheme = action_components.scheme.clone();
+        let enctype = submitter.enctype();
+        let method = submitter.method();
+        let _target = submitter.target();
+        // TODO: Handle browsing contexts, partially loaded documents (step 16-17)
+
+        let parsed_data = match enctype {
+            UrlEncoded => serialize(form_data.iter().map(|d| (d.name.as_slice(), d.value.as_slice())), None),
+            _ => "".to_string() // TODO: Add serializers for the other encoding types
+        };
+
+        let mut load_data = LoadData::new(action_components);
+        // Step 18
+        match (scheme.as_slice(), method) {
+            (_, FormDialog) => return, // Unimplemented
+            ("http", FormGet) | ("https", FormGet) => {
+                load_data.url.query = Some(parsed_data);
+            },
+            ("http", FormPost) | ("https", FormPost) => {
+                load_data.method = Post;
+                load_data.data = Some(parsed_data.into_bytes());
+            },
+            // https://html.spec.whatwg.org/multipage/forms.html#submit-get-action
+            ("ftp", _) | ("javascript", _) | ("data", FormGet) => (),
+            _ => return // Unimplemented (data and mailto)
+        }
+
+        // This is wrong. https://html.spec.whatwg.org/multipage/forms.html#planned-navigation
+        let ScriptChan(ref script_chan) = win.script_chan;
+        script_chan.send(TriggerLoadMsg(win.page.id, load_data));
+    }
+
+    fn get_form_dataset(self, _submitter: Option<FormSubmitter>) -> Vec<FormDatum> {
+        fn clean_crlf(s: &str) -> DOMString {
+            // https://html.spec.whatwg.org/multipage/forms.html#constructing-the-form-data-set
+            // Step 4
+            let mut buf = "".to_string();
+            let mut prev = ' ';
+            for ch in s.chars() {
+                match ch {
+                    '\n' if prev != '\r' => {
+                        buf.push_char('\r');
+                        buf.push_char('\n');
+                    },
+                    '\n' => {
+                        buf.push_char('\n');
+                    },
+                    // This character isn't LF but is
+                    // preceded by CR
+                    _ if prev == '\r' => {
+                        buf.push_char('\r');
+                        buf.push_char('\n');
+                        buf.push_char(ch);
+                    },
+                    _ => buf.push_char(ch)
+                };
+                prev = ch;
+            }
+            // In case the last character was CR
+            if prev == '\r' {
+                buf.push_char('\n');
+            }
+            buf
+        }
+
+        let node: JSRef<Node> = NodeCast::from_ref(self);
+        // TODO: This is an incorrect way of getting controls owned
+        //       by the form, but good enough until html5ever lands
+        let mut data_set = node.traverse_preorder().filter_map(|child| {
+            if child.get_disabled_state() {
+                return None;
+            }
+            if child.ancestors().any(|a| a.type_id() == ElementNodeTypeId(HTMLDataListElementTypeId)) {
+                return None;
+            }
+            // XXXManishearth don't include it if it is a button but not the submitter
+            match child.type_id() {
+                ElementNodeTypeId(HTMLInputElementTypeId) => {
+                    let input: JSRef<HTMLInputElement> = HTMLInputElementCast::to_ref(child).unwrap();
+                    let ty = input.Type();
+                    let name = input.Name();
+                    match ty.as_slice() {
+                        "radio" | "checkbox" => {
+                            if !input.Checked() || name.is_empty() {
+                                return None;
+                            }
+                        },
+                        "image" => (),
+                        _ => {
+                            if name.is_empty() {
+                                return None;
+                            }
+                        }
+                    }
+
+                    let mut value = input.Value();
+                    match ty.as_slice() {
+                        "image" => None, // Unimplemented
+                        "radio" | "checkbox" => {
+                            if value.is_empty() {
+                                value = "on".to_string();
+                            }
+                            Some(FormDatum {
+                                ty: ty,
+                                name: name,
+                                value: value
+                            })
+                        },
+                        "file" => None, // Unimplemented
+                        _ => Some(FormDatum {
+                            ty: ty,
+                            name: name,
+                            value: input.Value()
+                        })
+                    }
+                }
+                ElementNodeTypeId(HTMLButtonElementTypeId) => {
+                    // Unimplemented
+                    None
+                }
+                ElementNodeTypeId(HTMLSelectElementTypeId) => {
+                    // Unimplemented
+                    None
+                }
+                ElementNodeTypeId(HTMLObjectElementTypeId) => {
+                    // Unimplemented
+                    None
+                }
+                ElementNodeTypeId(HTMLTextAreaElementTypeId) => {
+                    // Unimplemented
+                    None
+                }
+                _ => None
+            }
+        });
+        // TODO: Handle `dirnames` (needs directionality support)
+        //       https://html.spec.whatwg.org/multipage/dom.html#the-directionality
+        let mut ret: Vec<FormDatum> = data_set.collect();
+        for mut datum in ret.iter_mut() {
+            match datum.ty.as_slice() {
+                "file" | "textarea" => (),
+                _ => {
+                    datum.name = clean_crlf(datum.name.as_slice());
+                    datum.value = clean_crlf(datum.value.as_slice());
+                }
+            }
+        };
+        ret
+    }
 }
 
 impl Reflectable for HTMLFormElement {
@@ -142,3 +345,67 @@ impl Reflectable for HTMLFormElement {
         self.htmlelement.reflector()
     }
 }
+
+// TODO: add file support
+pub struct FormDatum {
+    pub ty: DOMString,
+    pub name: DOMString,
+    pub value: DOMString
+}
+
+pub enum FormEncType {
+    TextPlainEncoded,
+    UrlEncoded,
+    FormDataEncoded
+}
+
+pub enum FormMethod {
+    FormGet,
+    FormPost,
+    FormDialog
+}
+
+pub enum FormSubmitter<'a> {
+    FormElement(JSRef<'a, HTMLFormElement>)
+    // TODO: Submit buttons, image submit, etc etc
+}
+
+impl<'a> FormSubmitter<'a> {
+    fn action(&self) -> DOMString {
+        match *self {
+            FormElement(form) => form.Action()
+        }
+    }
+
+    fn enctype(&self) -> FormEncType {
+        match *self {
+            FormElement(form) => {
+                match form.Enctype().as_slice() {
+                    "multipart/form-data" => FormDataEncoded,
+                    "text/plain" => TextPlainEncoded,
+                    // https://html.spec.whatwg.org/multipage/forms.html#attr-fs-enctype
+                    // urlencoded is the default
+                    _ => UrlEncoded
+                }
+            }
+        }
+    }
+
+    fn method(&self) -> FormMethod {
+        match *self {
+            FormElement(form) => {
+                match form.Method().as_slice() {
+                    "dialog" => FormDialog,
+                    "post" => FormPost,
+                    _ => FormGet
+                }
+            }
+        }
+    }
+
+    fn target(&self) -> DOMString {
+        match *self {
+            FormElement(form) => form.Target()
+        }
+    }
+}