Add file backend support for Blob and related

Changes include:
- Add BlobImpl to Blob, and related caching mechanism
- Expose ResourceThreads to document_loader, workerglobalscope, worker, and global
- Fix encode_multipart_form_data
- Other small fixes to accommodate the above changes

1 files changed, 10 insertions, 4 deletions

diff --git a/components/script/dom/htmlformelement.rs b/components/script/dom/htmlformelement.rs
index 50490ec879f..7f54fc7842b 100644
--- a/components/script/dom/htmlformelement.rs
+++ b/components/script/dom/htmlformelement.rs
@@ -40,6 +40,7 @@ use dom::window::Window;
 use encoding::EncodingRef;
 use encoding::all::UTF_8;
 use encoding::label::encoding_from_whatwg_label;
+use encoding::types::DecoderTrap;
 use hyper::header::{Charset, ContentDisposition, ContentType, DispositionParam, DispositionType};
 use hyper::method::Method;
 use msg::constellation_msg::{LoadData, PipelineId};
@@ -47,7 +48,6 @@ use rand::random;
 use script_thread::{MainThreadScriptMsg, Runnable};
 use std::borrow::ToOwned;
 use std::cell::Cell;
-use std::str::from_utf8;
 use std::sync::mpsc::Sender;
 use string_cache::Atom;
 use task_source::dom_manipulation::DOMManipulationTask;
@@ -281,7 +281,7 @@ impl HTMLFormElement {
         let encoding = encoding.unwrap_or(self.pick_encoding());
 
         //  Step 3
-        let charset = &*encoding.whatwg_name().unwrap();
+        let charset = &*encoding.whatwg_name().unwrap_or("UTF-8");
 
         // Step 4
         for entry in form_data.iter_mut() {
@@ -309,12 +309,18 @@ impl HTMLFormElement {
                         DispositionParam::Filename(Charset::Ext(String::from(charset.clone())),
                                                    None,
                                                    f.name().clone().into()));
-                    let content_type = ContentType(f.upcast::<Blob>().Type().parse().unwrap());
+                    // https://tools.ietf.org/html/rfc7578#section-4.4
+                    let content_type = ContentType(f.upcast::<Blob>().Type()
+                                                    .parse().unwrap_or(mime!(Text / Plain)));
                     result.push_str(&*format!("Content-Disposition: {}\r\n{}\r\n\r\n",
                         content_disposition,
                         content_type));
 
-                    result.push_str(from_utf8(&f.upcast::<Blob>().get_data().get_bytes()).unwrap());
+                    let slice = f.upcast::<Blob>().get_slice_or_empty();
+
+                    let decoded = encoding.decode(&slice.get_bytes(), DecoderTrap::Replace)
+                                          .expect("Invalid encoding in file");
+                    result.push_str(&decoded);
                 }
             }
         }