GN file generation

Add logic for writing GN files from descriptions.

Bug: 1291994
Change-Id: Icc243953aa2ac6c18d5ecec854ca9d6ae1d99d76

Cq-Include-Trybots: luci.chromium.try:android-rust-arm-dbg,android-rust-arm-rel,linux-rust-x64-dbg,linux-rust-x64-rel
Change-Id: Icc243953aa2ac6c18d5ecec854ca9d6ae1d99d76
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3820264
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Collin Baker <collinbaker@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Auto-Submit: Collin Baker <collinbaker@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1034727}

tools/crates/gnrt/BUILD.gn

@@ -1,4 +1,4 @@
-# Copyright 2022 The Chromium Authors. All rights reserved.
+# Copyright 2022 The Chromium Authors.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -19,6 +19,7 @@ rust_static_library("gnrt_lib") {
   sources = [
     "crates.rs",
     "deps.rs",
+    "gn.rs",
     "lib.rs",
     "manifest.rs",
     "paths.rs",
@@ -45,6 +46,7 @@ test("gnrt_unittests") {
   rs_sources = [
     "crates_unittest.rs",
     "deps_unittest.rs",
+    "gn_unittest.rs",
     "manifest_unittest.rs",
     "platforms_unittest.rs",
   ]
@@ -61,6 +63,7 @@ test("gnrt_unittests") {
     "//third_party/rust/semver/v1:lib",
     "//third_party/rust/serde/v1:lib",
     "//third_party/rust/serde_json/v1:lib",
+    "//third_party/rust/tempfile/v3:lib",
     "//third_party/rust/toml/v0_5:test_support",
   ]
 

tools/crates/gnrt/crates.rs

@@ -1,4 +1,4 @@
-// Copyright 2022 The Chromium Authors. All rights reserved.
+// Copyright 2022 The Chromium Authors.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -210,12 +210,20 @@ pub struct ThirdPartyCrate {
 }
 
 impl ThirdPartyCrate {
-    /// The location of this crate relative to the third-party Rust crate
-    /// directory. Crates are laid out according to their name and epoch.
-    pub fn crate_path(&self) -> PathBuf {
+    /// The location of this crate's directory, including its source subdir and
+    /// build files, relative to the third-party Rust crate directory. Crates
+    /// are laid out according to their name and epoch.
+    pub fn build_path(&self) -> PathBuf {
         let mut path = PathBuf::new();
         path.push(NormalizedName::from_crate_name(&self.name).0);
         path.push(self.epoch.to_string());
+        path
+    }
+
+    /// The location of this crate's source relative to the third-party Rust
+    /// crate directory.
+    pub fn crate_path(&self) -> PathBuf {
+        let mut path = self.build_path();
         path.push("crate");
         path
     }

tools/crates/gnrt/crates_unittest.rs

@@ -1,4 +1,4 @@
-// Copyright 2022 The Chromium Authors. All rights reserved.
+// Copyright 2022 The Chromium Authors.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 

tools/crates/gnrt/deps.rs

@@ -1,4 +1,4 @@
-// Copyright 2022 The Chromium Authors. All rights reserved.
+// Copyright 2022 The Chromium Authors.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 

tools/crates/gnrt/deps_unittest.rs

@@ -1,4 +1,4 @@
-// Copyright 2022 The Chromium Authors. All rights reserved.
+// Copyright 2022 The Chromium Authors.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.