Document common changes needed during a 0.x -> 1.x upgrade

README.md

@@ -6,3 +6,5 @@ rust-url
 URL library for Rust, based on the [URL Standard](https://url.spec.whatwg.org/).
 
 [Documentation](https://servo.github.io/rust-url/url/index.html)
+
+Please see [UPGRADING.md](https://github.com/servo/rust-url/blob/master/UPGRADING.md) if you are upgrading from 0.x to 1.x.

UPGRADING.md

@@ -0,0 +1,177 @@
+# Guide to upgrading from url 0.x to 1.x
+
+* The fields of `Url` are now private because the `Url` constructor, parser, and setters maintain invariants that could be violated if you were to set the fields directly. Instead of accessing, for example, `url.scheme`, use the getter method, such as `url.scheme()`. Instead of assigning directly to a field, for example `url.scheme = "https".to_string()`, use the setter method, such as `url.set_scheme("https").unwrap()` (the setters return a `Result` that must be used).
+
+* The methods of `Url` now return `&str` instead of `String`, thus reducing allocations and making serialization cheap.
+
+* The `path()` method on `url::Url` instances used to return `Option<&[String]>`; now it returns `&str`. If you would like functionality more similar to the old behavior of `path()`, use `path_segments()` that returns `Option<str::Split<char>>`.
+
+    Before upgrading:
+
+        let issue_list_url = Url::parse(
+             "https://github.com/rust-lang/rust/issues?labels=E-easy&state=open"
+        ).unwrap();
+        assert_eq!(issue_list_url.path(), Some(&["rust-lang".to_string(),
+                                                 "rust".to_string(),
+                                                 "issues".to_string()][..]));
+
+    After upgrading:
+
+        let issue_list_url = Url::parse(
+             "https://github.com/rust-lang/rust/issues?labels=E-easy&state=open"
+        ).unwrap();
+        assert_eq!(issue_list_url.path(), "/rust-lang/rust/issues");
+        assert_eq!(issue_list_url.path_segments().map(|c| c.collect::<Vec<_>>()),
+                   Some(vec!["rust-lang", "rust", "issues"]));
+
+* The `path_mut()` method on `url::Url` instances that allowed modification of a URL's path has been replaced by `path_segments_mut()`.
+
+    Before upgrading:
+
+        let mut url = Url::parse("https://github.com/rust-lang/rust").unwrap();
+        url.path_mut().unwrap().push("issues");
+
+    After upgrading:
+
+        let mut url = Url::parse("https://github.com/rust-lang/rust").unwrap();
+        url.path_segments_mut().unwrap().push("issues");
+
+* The `domain_mut()` method on `url::Url` instances that allowed modification of a URL's domain has been replaced by `set_host()` and `set_ip_host()`.
+
+* The `host()` method on `url::Url` instances used to return `Option<&Host>`; now it returns `Option<Host<&str>>`. The `serialize_host()` method that returned `Option<String>` has been replaced by the `host_str()` method that returns `Option<&str>`.
+
+* The `serialize()` method on `url::Url` instances that returned `String` has been replaced by an `as_str()` method that returns `&str`.
+
+    Before upgrading:
+
+        let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
+        assert_eq!(this_document.serialize(), "http://servo.github.io/rust-url/url/index.html".to_string());
+
+    After upgrading:
+
+        let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
+        assert_eq!(this_document.as_str(), "http://servo.github.io/rust-url/url/index.html");
+
+* `url::UrlParser` has been replaced by `url::Url::parse()` and `url::Url::join()`.
+
+    Before upgrading:
+
+        let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
+        let css_url = UrlParser::new().base_url(&this_document).parse("../main.css").unwrap();
+        assert_eq!(css_url.serialize(), "http://servo.github.io/rust-url/main.css".to_string());
+
+    After upgrading:
+
+        let this_document = Url::parse("http://servo.github.io/rust-url/url/index.html").unwrap();
+        let css_url = this_document.join("../main.css").unwrap();
+        assert_eq!(css_url.as_str(), "http://servo.github.io/rust-url/main.css");
+
+* `url::parse_path()` and `url::UrlParser::parse_path()` have been removed without replacement. As a workaround, you can give a base URL that you then ignore too `url::Url::parse()`.
+
+    Before upgrading:
+
+        let (path, query, fragment) = url::parse_path("/foo/bar/../baz?q=42").unwrap();
+        assert_eq!(path, vec!["foo".to_string(), "baz".to_string()]);
+        assert_eq!(query, Some("q=42".to_string()));
+        assert_eq!(fragment, None);
+
+    After upgrading:
+
+        let base = Url::parse("http://example.com").unwrap();
+        let with_path = base.join("/foo/bar/../baz?q=42").unwrap();
+        assert_eq!(with_path.path(), "/foo/baz");
+        assert_eq!(with_path.query(), Some("q=42"));
+        assert_eq!(with_path.fragment(), None);
+
+* The `url::form_urlencoded::serialize()` method has been replaced with the `url::form_urlencoded::Serializer` struct. Instead of calling `serialize()` with key/value pairs, create a new `Serializer` with a new string, call the `extend_pairs()` method on the `Serializer` instance with the key/value pairs as the argument, then call `finish()`.
+
+    Before upgrading:
+
+        let form = url::form_urlencoded::serialize(form.iter().map(|(k, v)| {
+            (&k[..], &v[..])
+        }));
+
+    After upgrading:
+
+        let form = url::form_urlencoded::Serializer::new(String::new()).extend_pairs(
+            form.iter().map(|(k, v)| { (&k[..], &v[..]) })
+        ).finish();
+
+* The `set_query_from_pairs()` method on `url::Url` instances that took key/value pairs has been replaced with `query_pairs_mut()`, which allows you to modify the `url::Url`'s query pairs.
+
+    Before upgrading:
+
+        let mut url = Url::parse("https://duckduckgo.com/").unwrap();
+        let pairs = vec![
+            ("q", "test"),
+            ("ia", "images"),
+        ];
+        url.set_query_from_pairs(pairs.iter().map(|&(k, v)| {
+            (&k[..], &v[..])
+        }));
+
+    After upgrading:
+
+        let mut url = Url::parse("https://duckduckgo.com/").unwrap();
+        let pairs = vec![
+            ("q", "test"),
+            ("ia", "images"),
+        ];
+        url.query_pairs_mut().clear().extend_pairs(
+          pairs.iter().map(|&(k, v)| { (&k[..], &v[..]) })
+        );
+
+* `url::SchemeData`, its variants `Relative` and `NonRelative`, and the struct `url::RelativeSchemeData` have been removed. Instead of matching on these variants to determine if you have a URL in a relative scheme such as HTTP versus a URL in a non-relative scheme as data, use the `cannot_be_a_base()` method to determine which kind you have.
+
+    Before upgrading:
+
+        match url.scheme_data {
+            url::SchemeData::Relative(..) => {}
+            url::SchemeData::NonRelative(..) => {
+                return Err(human(format!("`{}` must have relative scheme \
+                                          data: {}", field, url)))
+            }
+        }
+
+    After upgrading:
+
+        if url.cannot_be_a_base() {
+            return Err(human(format!("`{}` must have relative scheme \
+                                      data: {}", field, url)))
+        }
+
+* The functions `url::whatwg_scheme_type_mapper()`, the `SchemeType` enum, and the `scheme_type_mapper()` method on `url::UrlParser` instances have been removed. `SchemeType` had a method for getting the `default_port()`; to replicate this functionality, use the method `port_or_known_default()` on `url::Url` instances. The `port_or_default()` method on `url::Url` instances has been removed; use `port_or_known_default()` instead.
+
+    Before upgrading:
+
+        let port = match whatwg_scheme_type_mapper(&url.scheme) {
+            SchemeType::Relative(port) => port,
+            _ => return Err(format!("Invalid special scheme: `{}`",
+                                    raw_url.scheme)),
+        };
+
+    After upgrading:
+
+        let port = match url.port_or_known_default() {
+            Some(port) => port,
+            _ => return Err(format!("Invalid special scheme: `{}`",
+                                    url.scheme())),
+        };
+
+* The following formatting utilities have been removed without replacement; look at their linked previous implementations if you would like to replicate the functionality in your code:
+  * [`url::format::PathFormatter`](https://github.com/servo/rust-url/pull/176/commits/9e759f18726c8e1343162922b87163d4dd08fe3c#diff-0bb16ac13b75e9b568fa4aff61b0e71dL24)
+  * [`url::format::UserInfoFormatter`](https://github.com/servo/rust-url/pull/176/commits/9e759f18726c8e1343162922b87163d4dd08fe3c#diff-0bb16ac13b75e9b568fa4aff61b0e71dL50)
+  * [`url::format::UrlNoFragmentFormatter`](https://github.com/servo/rust-url/pull/176/commits/9e759f18726c8e1343162922b87163d4dd08fe3c#diff-0bb16ac13b75e9b568fa4aff61b0e71dL70)
+
+* `url::percent_encoding::percent_decode()` used to have a return type of `Vec<u8>`; now it returns an iterator of decoded `u8` bytes that also implements `Into<Cow<u8>>`.
+
+* The `url::percent_encoding::EncodeSet` struct and constant instances used with `url::percent_encoding::percent_encode()` have been changed to structs that implement the trait `url::percent_encoding::EncodeSet`.
+  * `SIMPLE_ENCODE_SET`, `QUERY_ENCODE_SET`, `DEFAULT_ENCODE_SET`, and `USERINFO_ENCODE_SET` have the same behavior.
+  * `USERNAME_ENCODE_SET` and `PASSWORD_ENCODE_SET` have been removed; use `USERINFO_ENCODE_SET` instead.
+  * `HTTP_VALUE_ENCODE_SET` has been removed; an implementation of it in the new types can be found [in hyper's source](https://github.com/hyperium/hyper/blob/67436c5bf615cf5a55a71e32b788afef5985570e/src/header/parsing.rs#L131-L138) if you need to replicate this functionality in your code.
+  * `FORM_URLENCODED_ENCODE_SET` has been removed; instead, use the functionality in `url::form_urlencoded`.
+  * `PATH_SEGMENT_ENCODE_SET` has been added for use on '/'-separated path segments.
+
+* `url::percent_encoding::percent_decode_to()` has been removed. Use `url::percent_encoding::percent_decode()` and manage pushing the results into a data structure yourself.
+* A number of `ParseError` variants have changed. [See the documentation for the current set](http://servo.github.io/rust-url/url/enum.ParseError.html).
+* `url::OpaqueOrigin::new()` and `url::Origin::UID(OpaqueOrigin)` have been replaced by `url::Origin::new_opaque()` and `url::Origin::Opaque(OpaqueOrigin)`, respectively.