From 4556d3935340f19c3b9ce8dc6cd3d0290441a447 Mon Sep 17 00:00:00 2001
From: Marshall Pierce <marshallpierce@google.com>
Date: Wed, 30 Aug 2023 11:14:49 -0600
Subject: [PATCH] Use pdl-compiler directly

If the `pdlc` binary is not available, use `pdl_compiler` as a library
instead.

Also do some misc tidying of the build script, since it looks like the
output path was being derived in different ways with the same result.
---
 .github/workflows/build.yml |  8 +++--
 .gitignore                  |  1 +
 rust/Cargo.toml             |  3 ++
 rust/build.rs               | 65 ++++++++++++++++++++-----------------
 4 files changed, 45 insertions(+), 32 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 51a2059..6214247 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -26,9 +26,13 @@ jobs:
         with:
           submodules: recursive
 
+      - name: Check Cargo build
+        run: |
+          cargo test
+
       - name: Install dependencies
         run: |
-          cargo install pdl-compiler --version 0.2.2
+          cargo install pdl-compiler --version 0.2.3
 
       - name: Build
         run: |
@@ -65,7 +69,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          cargo install pdl-compiler --version 0.2.2
+          cargo install pdl-compiler --version 0.2.3
           python3 -m pip install hatch
 
       - name: Set VERSION
diff --git a/.gitignore b/.gitignore
index fd2305f..8e2a49f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 Cargo.lock
 target/
 bazel-*
+/.idea
diff --git a/rust/Cargo.toml b/rust/Cargo.toml
index 1510574..ad004de 100644
--- a/rust/Cargo.toml
+++ b/rust/Cargo.toml
@@ -31,6 +31,9 @@ pin-utils = "0.1.0"
 rand = "0.8.3"
 thiserror = "1.0.23"
 
+[build-dependencies]
+pdl-compiler = "0.2.3"
+
 [lib]
 path="src/lib.rs"
 crate-type = ["staticlib"]
diff --git a/rust/build.rs b/rust/build.rs
index 793e1f9..e6518dd 100644
--- a/rust/build.rs
+++ b/rust/build.rs
@@ -16,6 +16,7 @@ use std::env;
 use std::fs::File;
 use std::path::{Path, PathBuf};
 use std::process::{Command, Stdio};
+use std::io::Write;
 
 fn main() {
     install_generated_module(
@@ -41,47 +42,51 @@ fn install_generated_module(module_name: &str, prebuilt_var: &str, pdl_name: &Pa
         Err(_) => PathBuf::from(module_name),
     };
 
-    if Path::new(module_prebuilt.as_os_str()).exists() {
-        let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-        std::fs::copy(
-            module_prebuilt.as_os_str().to_str().unwrap(),
-            out_dir.join(module_name).as_os_str().to_str().unwrap(),
-        )
-        .unwrap();
+    let out_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join(module_name);
+
+    if module_prebuilt.exists() {
+        std::fs::copy(module_prebuilt, &out_path).unwrap();
     } else {
-        generate_module(pdl_name);
+        generate_module(pdl_name, &out_path);
     }
+
+    // set var for use in `include!`
+    println!("cargo:rustc-env={}={}", prebuilt_var, out_path.to_str().unwrap());
 }
 
-fn generate_module(in_file: &PathBuf) {
-    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
-    let out_file =
-        File::create(out_dir.join(in_file.file_name().unwrap()).with_extension("rs")).unwrap();
+fn generate_module(in_file: &Path, out_path: &Path) {
+    let mut out_file = File::create(out_path).unwrap();
 
     // Find the pdl tool. Expecting it at CARGO_HOME/bin
-    let pdl = match env::var("CARGO_HOME") {
+    let pdlc = match env::var("CARGO_HOME") {
         Ok(dir) => PathBuf::from(dir).join("bin").join("pdlc"),
         Err(_) => PathBuf::from("pdlc"),
     };
 
-    if !Path::new(pdl.as_os_str()).exists() {
-        panic!("pdl not found in the current environment: {:?}", pdl.as_os_str().to_str().unwrap());
-    }
+    if pdlc.exists() {
+        let output = Command::new(pdlc.as_os_str().to_str().unwrap())
+            .arg("--output-format")
+            .arg("rust")
+            .arg(in_file)
+            .stdout(Stdio::from(out_file))
+            .output()
+            .unwrap();
 
-    println!("cargo:rerun-if-changed={}", in_file.display());
-    let output = Command::new(pdl.as_os_str().to_str().unwrap())
-        .arg("--output-format")
-        .arg("rust")
-        .arg(in_file)
-        .stdout(Stdio::from(out_file))
-        .output()
-        .unwrap();
+        println!(
+            "Status: {}, stderr: {}",
+            output.status,
+            String::from_utf8_lossy(output.stderr.as_slice())
+        );
 
-    println!(
-        "Status: {}, stderr: {}",
-        output.status,
-        String::from_utf8_lossy(output.stderr.as_slice())
-    );
+        assert!(output.status.success());
+    } else {
+        // use pdl_compiler as a library
+        let mut sources = pdl_compiler::ast::SourceDatabase::new();
+        let parsed_file = pdl_compiler::parser::parse_file(&mut sources, &in_file.to_str().expect("Filename is not UTF-8").to_string()).expect("PDL parse failed");
+        let analyzed_file = pdl_compiler::analyzer::analyze(&parsed_file).expect("PDL analysis failed");
+        let rust_source = pdl_compiler::backends::rust::generate(&sources, &analyzed_file);
+        out_file.write_all(rust_source.as_bytes()).expect("Could not write to output file");
+    }
 
-    assert!(output.status.success());
+    println!("cargo:rerun-if-changed={}", in_file.display());
 }