Test that Servo_* functions have the right signatures

Fixes #12992

tests/unit/stylo/Cargo.toml

@@ -4,6 +4,8 @@ version = "0.0.1"
 authors = ["The Servo Project Developers"]
 license = "MPL-2.0"
 
+build = "build.rs"
+
 [lib]
 name = "stylo_tests"
 path = "lib.rs"
@@ -11,6 +13,15 @@ doctest = false
 
 [dependencies]
 app_units = "0.3"
-cssparser = {version = "0.7", features = ["heap_size"]}
-style = {path = "../../../components/style", features = ["gecko"]}
+env_logger = "0.3"
+euclid = "0.10.1"
+lazy_static = "0.2"
+libc = "0.2"
+log = {version = "0.3.5", features = ["release_max_level_info"]}
+num_cpus = "0.2.2"
+parking_lot = "0.3"
+selectors = "0.13"
+url = "1.2"
 style_traits = {path = "../../../components/style_traits"}
+geckoservo = {path = "../../../ports/geckolib"}
+style = {path = "../../../components/style", features = ["gecko"]}

tests/unit/stylo/build.rs

@@ -0,0 +1,13 @@
+/* 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/. */
+
+use std::process::Command;
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=check_bindings.py");
+    println!("cargo:rerun-if-changed=../../../ports/geckolib/glue.rs");
+    assert!(Command::new("python").arg("./check_bindings.py")
+                                  .spawn().unwrap().wait().unwrap().success());
+}

tests/unit/stylo/check_bindings.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+
+# 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/.
+
+import os
+import re
+
+ROOT_PATH = os.path.join("..", "..", "..")
+INPUT_FILE = os.path.join(ROOT_PATH, "components", "style", "gecko_bindings", "bindings.rs")
+OUTPUT_FILE = os.path.join(os.environ["OUT_DIR"], "check_bindings.rs")
+GLUE_FILE = os.path.join(ROOT_PATH, "ports", "geckolib", "glue.rs")
+GLUE_OUTPUT_FILE = os.path.join(os.environ["OUT_DIR"], "glue.rs")
+
+TEMPLATE = """\
+    [ Servo_{name}, bindings::Servo_{name} ];
+"""
+
+with open(INPUT_FILE, "r") as bindings, open(OUTPUT_FILE, "w+") as tests:
+    tests.write("fn assert_types() {\n")
+
+    pattern = re.compile("fn\s*Servo_([a-zA-Z0-9_]+)\s*\(")
+
+    for line in bindings:
+        match = pattern.search(line)
+
+        # GetStyleVariables is a Servo_* function, but temporarily defined on
+        # the gecko side
+        if match and match.group(1) != "GetStyleVariables":
+            tests.write(TEMPLATE.format(name=match.group(1)))
+
+    tests.write("}\n")
+
+with open(GLUE_FILE, "r") as glue, open(GLUE_OUTPUT_FILE, "w+") as glue_output:
+    for line in glue:
+        glue_output.write(line.replace("pub extern \"C\" fn", "pub unsafe extern \"C\" fn"))

tests/unit/stylo/lib.rs

@@ -3,8 +3,16 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 extern crate app_units;
-extern crate cssparser;
+extern crate env_logger;
+extern crate euclid;
+extern crate geckoservo;
+extern crate libc;
+#[macro_use] extern crate log;
+extern crate parking_lot;
 extern crate style;
-extern crate style_traits;
+extern crate url;
 
 mod sanity_checks;
+
+mod servo_function_signatures;
+

tests/unit/stylo/servo_function_signatures.rs

@@ -0,0 +1,20 @@
+/* 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/. */
+
+#![allow(unused)]
+
+use self::glue::*;
+use style::gecko_bindings::bindings;
+use style::gecko_properties::*;
+
+include!(concat!(env!("OUT_DIR"), "/check_bindings.rs"));
+
+#[allow(non_snake_case, unused_unsafe, private_no_mangle_fns)]
+mod glue {
+    // this module pretends to be glue.rs, with the safe functions swapped for unsafe ones. This is
+    // a hack to compensate for the fact that `fn` types cannot coerce to `unsafe fn` types. The
+    // imports are populated with the same things so the type assertion should be equivalent
+    use geckoservo::*;
+    include!(concat!(env!("OUT_DIR"), "/glue.rs"));
+}