feat(performance): Add benchmarks

These are based on Tera and Handlebars. shopify/liquid's are a bit more
work to port over.

The process for running this has been documented in `CONTRIBUTING.md`,
along with a lot of other things.

CONTRIBUTING.md

@@ -1,18 +1,43 @@
-Thanks for contributing! :snowman:
+Thanks for wanting to contribute! :snowman:
 
-Feel free to create issues and make pull requests, we'll try to quickly review them.
+Feel free to create issues or make pull requests, we'll try to quickly review them.
+
+If you need assistance, you can join the `#cobalt` channel on `irc.mozilla.org` or the Gitter chat [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/cobalt-org/cobalt.rs)
+
+We want you to feel safe and welcome and will enforce the **[The Rust Code of Conduct](https://www.rust-lang.org/conduct.html)** on all communication platforms of this project.
+Please contact [@johannhof](https://github.com/johannhof) for questions or in cases of violation.
+
+# Issues
+
+This project aims to be a Rust implementation of [https://shopify.github.io/liquid/](Liquid).
+- Notice that we deviate from shopify/liquid? Please, open an issue if there isn't an [existing one](https://github.com/cobalt-org/liquid-rust/labels/shopify-compatibility)
+- Want a new tag or filter? Check for an [https://github.com/cobalt-org/liquid-rust/labels/enhancement](existing issue) and open one if needed.
+
+# Pull Requests
+
+## Project Ideas
 
 If you're looking for things to do check out the [open issues](https://github.com/cobalt-org/cobalt.rs/issues), especially those with the
 [easy](https://github.com/cobalt-org/liquid-rust/issues?q=is%3Aissue+is%3Aopen+label%3Aeasy) and [help wanted](https://github.com/cobalt-org/liquid-rust/issues?q=is%3Aissue+is%3Aopen+label%3A%22help+wanted%22) flags.
 Or take a grep through [all TODO comments](https://github.com/cobalt-org/liquid-rust/search?q=TODO) in the code and feel free to help us out there!
 
+## Best Practices
+
+We appreciate your help as-is.  We'd love to help you through the process for contributing.  We have some suggestions to help make things go more smoothly.
+
 🌈 **Here's a checklist for the perfect pull request:**
 - [ ] Make sure existing tests still work by running `cargo test` locally.
 - [ ] Add new tests for any new feature or regression tests for bugfixes.
 - [ ] Install [Clippy](https://github.com/Manishearth/rust-clippy) and run `rustup run nightly cargo clippy` to catch common mistakes (will be checked by Travis)
 - [ ] Install [Rustfmt](https://github.com/rust-lang-nursery/rustfmt) and run `cargo fmt` to format your code (will also be checked by Travis)
 
-If you need assistance, you can join the `#cobalt` channel on `irc.mozilla.org` or the Gitter chat [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/cobalt-org/cobalt.rs)
+For new tags or filters, we recommend
+- Open an RFC Issue for discussing what the API should be.  We'd like to avoid disrupting people once they start using a feature.
+- Consider incubating it in your code first to so it can be iterated on to find what works well.
+- Checkout prior art with [https://help.shopify.com/themes/liquid](Shopify's proprietary extensions) or [https://jekyllrb.com/docs/templates/](Jekyll's extensions).
 
-We want you to feel safe and welcome and will enforce the **[The Rust Code of Conduct](https://www.rust-lang.org/conduct.html)** on all communication platforms of this project.
-Please contact [@johannhof](https://github.com/johannhof) for questions or in cases of violation.
+If you're interested in benchmarking your changes
+- Be sure to get some before and afters on the same machine
+- Rust nightly is required.  You'll need to run `rustup run nightly -- cargo bench`
+
+Hopefully we get this integrated into your CI process.

benches/liquid.rs

@@ -0,0 +1,117 @@
+#![feature(test)]
+
+extern crate test;
+extern crate serde;
+extern crate serde_yaml;
+
+extern crate liquid;
+
+use liquid::Renderable;
+
+static TEXT_ONLY: &'static str = "Hello World";
+
+#[bench]
+fn bench_parse_text(b: &mut test::Bencher) {
+    b.iter(|| {
+               let options = liquid::LiquidOptions::with_known_blocks();
+               liquid::parse(TEXT_ONLY, options)
+           });
+}
+
+#[bench]
+fn bench_render_text(b: &mut test::Bencher) {
+    let options = liquid::LiquidOptions::with_known_blocks();
+    let template = liquid::parse(TEXT_ONLY, options).expect("Benchmark template parsing failed");
+
+    let data = liquid::Object::new();
+
+    b.iter(|| {
+               let mut context = liquid::Context::with_values(data.clone());
+               template.render(&mut context)
+           });
+}
+
+// Mirrors tera's VARIABLE_ONLY benchmark
+static VARIABLE_ONLY: &'static str = "{{product.name}}";
+static VARIABLE_ONLY_OBJECT: &'static str = "
+username: bob
+product:
+  - name: Moto G
+  - manufacturer: Motorola
+  - summary: A phone
+  - price: 100
+";
+
+#[bench]
+fn bench_parse_variable(b: &mut test::Bencher) {
+    b.iter(|| {
+               let options = liquid::LiquidOptions::with_known_blocks();
+               liquid::parse(VARIABLE_ONLY, options)
+           });
+}
+
+#[bench]
+fn bench_render_variable(b: &mut test::Bencher) {
+    let options = liquid::LiquidOptions::with_known_blocks();
+    let template =
+        liquid::parse(VARIABLE_ONLY, options).expect("Benchmark template parsing failed");
+
+    let data: liquid::Object =
+        serde_yaml::from_str(VARIABLE_ONLY_OBJECT).expect("Benchmark object parsing failed");
+
+    b.iter(|| {
+               let mut context = liquid::Context::with_values(data.clone());
+               template.render(&mut context)
+           });
+}
+
+// Mirrors handlebars' benchmark
+static ITERATE: &'static str = "<html>
+  <head>
+    <title>{{year}}</title>
+  </head>
+  <body>
+    <h1>CSL {{year}}</h1>
+    <ul>
+    {% for team in teams %}
+      <li class=\"champion\">
+      <b>{{team.name}}</b>: {{team.score}}
+      </li>
+    {{/each}}
+    </ul>
+  </body>
+</html>";
+static ITERATE_OBJECT: &'static str = "
+year: 2015
+teams:
+  - name: Jiangsu
+    score: 43
+  - name: Beijing
+    score: 27
+  - name: Guangzhou
+    score: 22
+  - name: Shandong
+    score: 12
+";
+
+#[bench]
+fn bench_parse_template(b: &mut test::Bencher) {
+    b.iter(|| {
+               let options = liquid::LiquidOptions::with_known_blocks();
+               liquid::parse(ITERATE, options)
+           });
+}
+
+#[bench]
+fn bench_render_template(b: &mut test::Bencher) {
+    let options = liquid::LiquidOptions::with_known_blocks();
+    let template = liquid::parse(ITERATE, options).expect("Benchmark template parsing failed");
+
+    let data: liquid::Object =
+        serde_yaml::from_str(ITERATE_OBJECT).expect("Benchmark object parsing failed");
+
+    b.iter(|| {
+               let mut context = liquid::Context::with_values(data.clone());
+               template.render(&mut context)
+           });
+}