Auto merge of #18676 - gterzian:continue_http_cache_work, r=jdm

Continue http cache work

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Work in progress, and not quite worth a review yet. (Continuation of https://github.com/servo/servo/pull/4117)

TODO

- [ ] cache metadata (find some subset of`net_traits::Metadata` that can be shared across threads, it seems the problem is mainly stuff inside `hyper::header` in the `headers` field)

- [ ] determine which other fields of a `Response` need to be cached, so a full and valid one can be returned upon a cache hit.

- [ ] determine how to best share the cache across fetch threads (inside HttpState like I tried now?)

- [ ] Spend more time reading the spec and make sure the cache follows it where it matters.

- [ ] Make the current wpt tests pass.

- [ ] More...

---
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- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix #12972  (github issue number if applicable).

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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components/script/dom/headers.rs

@@ -234,6 +234,12 @@ impl Headers {
         *self.header_list.borrow_mut() = hyper_headers;
     }
 
+    pub fn get_headers_list(&self) -> HyperHeaders {
+        let mut headers = HyperHeaders::new();
+        headers.extend(self.header_list.borrow_mut().iter());
+        headers
+    }
+
     // https://fetch.spec.whatwg.org/#concept-header-extract-mime-type
     pub fn extract_mime_type(&self) -> Vec<u8> {
         self.header_list.borrow().get_raw("content-type").map_or(vec![], |v| v[0].clone())

components/script/dom/request.rs

@@ -339,6 +339,9 @@ impl Request {
             _ => {},
         }
 
+        // Copy the headers list onto the headers of net_traits::Request
+        r.request.borrow_mut().headers = r.Headers().get_headers_list();
+
         // Step 32
         let mut input_body = if let RequestInfo::Request(ref input_request) = input {
             let input_request_request = input_request.request.borrow();
@@ -459,17 +462,7 @@ fn normalize_method(m: &str) -> HttpMethod {
 
 // https://fetch.spec.whatwg.org/#concept-method
 fn is_method(m: &ByteString) -> bool {
-    match m.to_lower().as_str() {
-        Some("get") => true,
-        Some("head") => true,
-        Some("post") => true,
-        Some("put") => true,
-        Some("delete") => true,
-        Some("connect") => true,
-        Some("options") => true,
-        Some("trace") => true,
-        _ => false,
-    }
+    m.as_str().is_some()
 }
 
 // https://fetch.spec.whatwg.org/#forbidden-method