1 files changed, 110 insertions, 0 deletions
diff --git a/gn.rs b/gn.rs
new file mode 100644
index 000000000..5d27b8bb0
--- /dev/null
+++ b/gn.rs
@@ -0,0 +1,110 @@
+// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
+// This is used in cli/build.rs and core/build.rs to interface with the GN build
+// system (which defines the deno build).
+
+use std::env;
+use std::path::{self, Path, PathBuf};
+use std::process::Command;
+
+pub struct Build {
+  gn_mode: String,
+  pub gn_out_dir: String,
+  pub gn_out_path: PathBuf,
+  pub check_only: bool,
+}
+
+impl Build {
+  pub fn setup() -> Build {
+    let gn_mode = if cfg!(target_os = "windows") {
+      // On Windows, we need to link with a release build of libdeno, because
+      // rust always uses the release CRT.
+      // TODO(piscisaureus): make linking with debug libdeno possible.
+      String::from("release")
+    } else {
+      // Cargo sets PROFILE to either "debug" or "release", which conveniently
+      // matches the build modes we support.
+      env::var("PROFILE").unwrap()
+    };
+
+    // cd into workspace root.
+    assert!(env::set_current_dir("..").is_ok());
+
+    let cwd = env::current_dir().unwrap();
+    // If not using host default target the output folder will change
+    // target/release will become target/$TARGET/release
+    // Gn should also be using this output directory as well
+    // most things will work with gn using the default
+    // output directory but some tests depend on artifacts
+    // being in a specific directory relative to the main build output
+    let gn_out_path = cwd.join(format!("target/{}", gn_mode.clone()));
+    let gn_out_dir = normalize_path(&gn_out_path);
+
+    // Tell Cargo when to re-run this file. We do this first, so these directives
+    // can take effect even if something goes wrong later in the build process.
+    println!("cargo:rerun-if-env-changed=DENO_BUILD_PATH");
+    // TODO: this is obviously not appropriate here.
+    println!("cargo:rerun-if-env-changed=APPVEYOR_REPO_COMMIT");
+
+    // This helps Rust source files locate the snapshot, source map etc.
+    println!("cargo:rustc-env=GN_OUT_DIR={}", gn_out_dir);
+
+    // Detect if we're being invoked by the rust language server (RLS).
+    // Unfortunately we can't detect whether we're being run by `cargo check`.
+    let check_only = env::var_os("CARGO")
+      .map(PathBuf::from)
+      .as_ref()
+      .and_then(|p| p.file_stem())
+      .and_then(|f| f.to_str())
+      .map(|s| s.starts_with("rls"))
+      .unwrap_or(false);
+
+    if check_only {
+      // Enable the 'check_only' feature, which enables some workarounds in the
+      // rust source code to compile successfully without a bundle and snapshot
+      println!("cargo:rustc-cfg=feature=\"check-only\"");
+    }
+
+    Build {
+      gn_out_dir,
+      gn_out_path,
+      check_only,
+      gn_mode,
+    }
+  }
+
+  pub fn run(&self, gn_target: &str) {
+    if !self.gn_out_path.join("build.ninja").exists() {
+      let status = Command::new("python")
+        .env("DENO_BUILD_PATH", &self.gn_out_dir)
+        .env("DENO_BUILD_MODE", &self.gn_mode)
+        .arg("./tools/setup.py")
+        .status()
+        .expect("setup.py failed");
+      assert!(status.success());
+    }
+
+    // TODO(ry) call ninja directly here, not python.
+    let status = Command::new("python")
+      .env("DENO_BUILD_PATH", &self.gn_out_dir)
+      .env("DENO_BUILD_MODE", &self.gn_mode)
+      .arg("./tools/build.py")
+      .arg(gn_target)
+      .arg("-v")
+      .status()
+      .expect("build.py failed");
+    assert!(status.success());
+  }
+}
+
+// Utility function to make a path absolute, normalizing it to use forward
+// slashes only. The returned value is an owned String, otherwise panics.
+fn normalize_path<T: AsRef<Path>>(path: T) -> String {
+  path
+    .as_ref()
+    .to_str()
+    .unwrap()
+    .to_owned()
+    .chars()
+    .map(|c| if path::is_separator(c) { '/' } else { c })
+    .collect()
+}