refactor(build): generate revision via build.rs

components/compositing/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.0.1"
 authors = ["The Servo Project Developers"]
 license = "MPL-2.0"
 publish = false
+build = "build.rs"
 
 [lib]
 name = "compositing"
@@ -29,3 +30,6 @@ style_traits = {path = "../style_traits"}
 time = "0.1.17"
 webrender = {git = "https://github.com/servo/webrender", features = ["capture"]}
 webrender_api = {git = "https://github.com/servo/webrender", features = ["ipc"]}
+
+[build-dependencies]
+toml = "0.4.5"

components/compositing/build.rs

@@ -0,0 +1,65 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+
+extern crate toml;
+
+use std::env;
+use std::fs::File;
+use std::io::{Read, Write};
+
+const WEBRENDER_REVISION_TEMPLATE: &'static str =
+"/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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/. */
+
+/// auto-generated by cargo. do not manually modify.
+pub const REVISION: &'static str = ";
+
+fn main() {
+    let current_path = env::current_dir().expect("Failed to access path to lockfile");
+    let lockfile_path = current_path.join("..").join("..").join("Cargo.lock");
+    let revision_file_path = current_path.join("webrender_revision.rs");
+
+    let mut existing_revision_exported = String::new();
+    match File::open(&revision_file_path) {
+        Ok(mut f) => {
+        f.read_to_string(&mut existing_revision_exported).unwrap_or_default();
+        },
+        Err(_) => ()
+    }
+
+    let mut lockfile = String::new();
+    File::open(lockfile_path).expect("Cannot open lockfile")
+        .read_to_string(&mut lockfile)
+        .expect("Failed to read lockfile");
+
+    match toml::from_str::<toml::value::Table>(&lockfile) {
+        Ok(result) => {
+            let packages = result.get("package").expect("Cargo lockfile should contain package list");
+
+            match *packages {
+                toml::Value::Array(ref arr) => {
+                    let source = arr
+                        .iter()
+                        .find(|pkg| pkg.get("name").and_then(|name| name.as_str()).unwrap_or("") == "webrender")
+                        .and_then(|pkg| pkg.get("source").and_then(|source| source.as_str()))
+                        .unwrap_or("unknown");
+
+                    let parsed: Vec<&str> = source.split("#").collect();
+                    let revision = if parsed.len() > 1 { parsed[1] } else { source };
+
+                    if let Some(_) = existing_revision_exported.find(revision) {
+                        return
+                    }
+
+                    let revision_contents = format!("{}\"{}\";", WEBRENDER_REVISION_TEMPLATE, revision);
+                    let mut revision_module_file = File::create(&revision_file_path).unwrap();
+                    write!(&mut revision_module_file, "{}", revision_contents).unwrap();
+                },
+                _ => panic!("Cannot find package definitions in lockfile")
+            }
+        },
+        Err(e) => panic!(e)
+    }
+}