bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/proc-macro-srv/src/lib.rs')
-rw-r--r--crates/proc-macro-srv/src/lib.rs130
1 files changed, 130 insertions, 0 deletions
diff --git a/crates/proc-macro-srv/src/lib.rs b/crates/proc-macro-srv/src/lib.rs
new file mode 100644
index 0000000000..52693547e5
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+++ b/crates/proc-macro-srv/src/lib.rs
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+//! RA Proc Macro Server
+//!
+//! This library is able to call compiled Rust custom derive dynamic libraries on arbitrary code.
+//! The general idea here is based on <https://github.com/fedochet/rust-proc-macro-expander>.
+//!
+//! But we adapt it to better fit RA needs:
+//!
+//! * We use `tt` for proc-macro `TokenStream` server, it is easier to manipulate and interact with
+//! RA than `proc-macro2` token stream.
+//! * By **copying** the whole rustc `lib_proc_macro` code, we are able to build this with `stable`
+//! rustc rather than `unstable`. (Although in general ABI compatibility is still an issue)…
+#![allow(unreachable_pub)]
+
+mod dylib;
+mod abis;
+
+use std::{
+ collections::{hash_map::Entry, HashMap},
+ env,
+ ffi::OsString,
+ fs,
+ path::{Path, PathBuf},
+ time::SystemTime,
+};
+
+use proc_macro_api::{
+ msg::{ExpandMacro, FlatTree, PanicMessage},
+ ProcMacroKind,
+};
+
+#[derive(Default)]
+pub(crate) struct ProcMacroSrv {
+ expanders: HashMap<(PathBuf, SystemTime), dylib::Expander>,
+}
+
+impl ProcMacroSrv {
+ pub fn expand(&mut self, task: ExpandMacro) -> Result<FlatTree, PanicMessage> {
+ let expander = self.expander(task.lib.as_ref()).map_err(|err| {
+ debug_assert!(false, "should list macros before asking to expand");
+ PanicMessage(format!("failed to load macro: {}", err))
+ })?;
+
+ let prev_env = EnvSnapshot::new();
+ for (k, v) in &task.env {
+ env::set_var(k, v);
+ }
+ let prev_working_dir = match task.current_dir {
+ Some(dir) => {
+ let prev_working_dir = std::env::current_dir().ok();
+ if let Err(err) = std::env::set_current_dir(&dir) {
+ eprintln!("Failed to set the current working dir to {}. Error: {:?}", dir, err)
+ }
+ prev_working_dir
+ }
+ None => None,
+ };
+
+ let macro_body = task.macro_body.to_subtree();
+ let attributes = task.attributes.map(|it| it.to_subtree());
+ let result = expander
+ .expand(&task.macro_name, &macro_body, attributes.as_ref())
+ .map(|it| FlatTree::new(&it));
+
+ prev_env.rollback();
+
+ if let Some(dir) = prev_working_dir {
+ if let Err(err) = std::env::set_current_dir(&dir) {
+ eprintln!(
+ "Failed to set the current working dir to {}. Error: {:?}",
+ dir.display(),
+ err
+ )
+ }
+ }
+
+ result.map_err(PanicMessage)
+ }
+
+ pub(crate) fn list_macros(
+ &mut self,
+ dylib_path: &Path,
+ ) -> Result<Vec<(String, ProcMacroKind)>, String> {
+ let expander = self.expander(dylib_path)?;
+ Ok(expander.list_macros())
+ }
+
+ fn expander(&mut self, path: &Path) -> Result<&dylib::Expander, String> {
+ let time = fs::metadata(path).and_then(|it| it.modified()).map_err(|err| {
+ format!("Failed to get file metadata for {}: {:?}", path.display(), err)
+ })?;
+
+ Ok(match self.expanders.entry((path.to_path_buf(), time)) {
+ Entry::Vacant(v) => v.insert(dylib::Expander::new(path).map_err(|err| {
+ format!("Cannot create expander for {}: {:?}", path.display(), err)
+ })?),
+ Entry::Occupied(e) => e.into_mut(),
+ })
+ }
+}
+
+struct EnvSnapshot {
+ vars: HashMap<OsString, OsString>,
+}
+
+impl EnvSnapshot {
+ fn new() -> EnvSnapshot {
+ EnvSnapshot { vars: env::vars_os().collect() }
+ }
+
+ fn rollback(self) {
+ let mut old_vars = self.vars;
+ for (name, value) in env::vars_os() {
+ let old_value = old_vars.remove(&name);
+ if old_value != Some(value) {
+ match old_value {
+ None => env::remove_var(name),
+ Some(old_value) => env::set_var(name, old_value),
+ }
+ }
+ }
+ for (name, old_value) in old_vars {
+ env::set_var(name, old_value)
+ }
+ }
+}
+
+pub mod cli;
+
+#[cfg(test)]
+mod tests;