internal: simplify handling of the build scripts

crates/project_model/src/build_scripts.rs

@@ -0,0 +1,207 @@
+//! Workspace information we get from cargo consists of two pieces. The first is
+//! the output of `cargo metadata`. The second is the output of running
+//! `build.rs` files (`OUT_DIR` env var, extra cfg flags) and compiling proc
+//! macro.
+//!
+//! This module implements this second part. We use "build script" terminology
+//! here, but it covers procedural macros as well.
+
+use std::{
+    path::PathBuf,
+    process::{Command, Stdio},
+};
+
+use anyhow::Result;
+use cargo_metadata::{camino::Utf8Path, Message};
+use la_arena::ArenaMap;
+use paths::AbsPathBuf;
+use rustc_hash::FxHashMap;
+use serde::Deserialize;
+
+use crate::{cfg_flag::CfgFlag, CargoConfig, CargoWorkspace, Package};
+
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
+pub struct WorkspaceBuildScripts {
+    pub(crate) outputs: ArenaMap<Package, BuildScriptOutput>,
+    error: Option<String>,
+}
+
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub(crate) struct BuildScriptOutput {
+    /// List of config flags defined by this package's build script.
+    pub(crate) cfgs: Vec<CfgFlag>,
+    /// List of cargo-related environment variables with their value.
+    ///
+    /// If the package has a build script which defines environment variables,
+    /// they can also be found here.
+    pub(crate) envs: Vec<(String, String)>,
+    /// Directory where a build script might place its output.
+    pub(crate) out_dir: Option<AbsPathBuf>,
+    /// Path to the proc-macro library file if this package exposes proc-macros.
+    pub(crate) proc_macro_dylib_path: Option<AbsPathBuf>,
+}
+
+impl WorkspaceBuildScripts {
+    pub fn run(
+        config: &CargoConfig,
+        workspace: &CargoWorkspace,
+        progress: &dyn Fn(String),
+    ) -> Result<WorkspaceBuildScripts> {
+        let mut cmd = Command::new(toolchain::cargo());
+
+        if config.wrap_rustc_in_build_scripts {
+            // Setup RUSTC_WRAPPER to point to `rust-analyzer` binary itself. We use
+            // that to compile only proc macros and build scripts during the initial
+            // `cargo check`.
+            let myself = std::env::current_exe()?;
+            cmd.env("RUSTC_WRAPPER", myself);
+            cmd.env("RA_RUSTC_WRAPPER", "1");
+        }
+        cmd.current_dir(workspace.workspace_root());
+        cmd.args(&["check", "--quiet", "--workspace", "--message-format=json"]);
+
+        // --all-targets includes tests, benches and examples in addition to the
+        // default lib and bins. This is an independent concept from the --targets
+        // flag below.
+        cmd.arg("--all-targets");
+
+        if let Some(target) = &config.target {
+            cmd.args(&["--target", target]);
+        }
+
+        if config.all_features {
+            cmd.arg("--all-features");
+        } else {
+            if config.no_default_features {
+                cmd.arg("--no-default-features");
+            }
+            if !config.features.is_empty() {
+                cmd.arg("--features");
+                cmd.arg(config.features.join(" "));
+            }
+        }
+
+        cmd.stdout(Stdio::piped()).stderr(Stdio::piped()).stdin(Stdio::null());
+
+        let mut res = WorkspaceBuildScripts::default();
+        // NB: Cargo.toml could have been modified between `cargo metadata` and
+        // `cargo check`. We shouldn't assume that package ids we see here are
+        // exactly those from `config`.
+        let mut by_id: FxHashMap<String, Package> = FxHashMap::default();
+
+        for package in workspace.packages() {
+            res.outputs.insert(package, BuildScriptOutput::default());
+            by_id.insert(workspace[package].id.clone(), package);
+        }
+
+        let mut callback_err = None;
+        let mut stderr = String::new();
+        let output = stdx::process::streaming_output(
+            cmd,
+            &mut |line| {
+                if callback_err.is_some() {
+                    return;
+                }
+
+                // Copy-pasted from existing cargo_metadata. It seems like we
+                // should be using sered_stacker here?
+                let mut deserializer = serde_json::Deserializer::from_str(line);
+                deserializer.disable_recursion_limit();
+                let message = Message::deserialize(&mut deserializer)
+                    .unwrap_or_else(|_| Message::TextLine(line.to_string()));
+
+                match message {
+                    Message::BuildScriptExecuted(message) => {
+                        let package = match by_id.get(&message.package_id.repr) {
+                            Some(it) => *it,
+                            None => return,
+                        };
+                        let cfgs = {
+                            let mut acc = Vec::new();
+                            for cfg in message.cfgs {
+                                match cfg.parse::<CfgFlag>() {
+                                    Ok(it) => acc.push(it),
+                                    Err(err) => {
+                                        callback_err = Some(anyhow::format_err!(
+                                            "invalid cfg from cargo-metadata: {}",
+                                            err
+                                        ));
+                                        return;
+                                    }
+                                };
+                            }
+                            acc
+                        };
+                        let package_build_data = &mut res.outputs[package];
+                        // cargo_metadata crate returns default (empty) path for
+                        // older cargos, which is not absolute, so work around that.
+                        if !message.out_dir.as_str().is_empty() {
+                            let out_dir =
+                                AbsPathBuf::assert(PathBuf::from(message.out_dir.into_os_string()));
+                            package_build_data.out_dir = Some(out_dir);
+                            package_build_data.cfgs = cfgs;
+                        }
+
+                        package_build_data.envs = message.env;
+                    }
+                    Message::CompilerArtifact(message) => {
+                        let package = match by_id.get(&message.package_id.repr) {
+                            Some(it) => *it,
+                            None => return,
+                        };
+
+                        progress(format!("metadata {}", message.target.name));
+
+                        if message.target.kind.iter().any(|k| k == "proc-macro") {
+                            // Skip rmeta file
+                            if let Some(filename) =
+                                message.filenames.iter().find(|name| is_dylib(name))
+                            {
+                                let filename = AbsPathBuf::assert(PathBuf::from(&filename));
+                                res.outputs[package].proc_macro_dylib_path = Some(filename);
+                            }
+                        }
+                    }
+                    Message::CompilerMessage(message) => {
+                        progress(message.target.name);
+                    }
+                    Message::BuildFinished(_) => {}
+                    Message::TextLine(_) => {}
+                    _ => {}
+                }
+            },
+            &mut |line| {
+                stderr.push_str(line);
+                stderr.push('\n');
+            },
+        )?;
+
+        for package in workspace.packages() {
+            let package_build_data = &mut res.outputs[package];
+            // inject_cargo_env(package, package_build_data);
+            if let Some(out_dir) = &package_build_data.out_dir {
+                // NOTE: cargo and rustc seem to hide non-UTF-8 strings from env! and option_env!()
+                if let Some(out_dir) = out_dir.as_os_str().to_str().map(|s| s.to_owned()) {
+                    package_build_data.envs.push(("OUT_DIR".to_string(), out_dir));
+                }
+            }
+        }
+
+        if !output.status.success() {
+            if stderr.is_empty() {
+                stderr = "cargo check failed".to_string();
+            }
+            res.error = Some(stderr)
+        }
+
+        Ok(res)
+    }
+}
+
+// FIXME: File a better way to know if it is a dylib.
+fn is_dylib(path: &Utf8Path) -> bool {
+    match path.extension().map(|e| e.to_string().to_lowercase()) {
+        None => false,
+        Some(ext) => matches!(ext.as_str(), "dll" | "dylib" | "so"),
+    }
+}