1 //! RA Proc Macro Server 2 //! 3 //! This library is able to call compiled Rust custom derive dynamic libraries on arbitrary code. 4 //! The general idea here is based on <https://github.com/fedochet/rust-proc-macro-expander>. 5 //! 6 //! But we adapt it to better fit RA needs: 7 //! 8 //! * We use `tt` for proc-macro `TokenStream` server, it is easier to manipulate and interact with 9 //! RA than `proc-macro2` token stream. 10 //! * By **copying** the whole rustc `lib_proc_macro` code, we are able to build this with `stable` 11 //! rustc rather than `unstable`. (Although in general ABI compatibility is still an issue)… 12 #![allow(unreachable_pub)] 13 14 mod dylib; 15 mod abis; 16 17 use std::{ 18 collections::{hash_map::Entry, HashMap}, 19 env, fs, 20 path::{Path, PathBuf}, 21 time::SystemTime, 22 }; 23 24 use proc_macro_api::{ 25 msg::{ExpandMacro, FlatTree, PanicMessage}, 26 ProcMacroKind, 27 }; 28 29 #[derive(Default)] 30 pub(crate) struct ProcMacroSrv { 31 expanders: HashMap<(PathBuf, SystemTime), dylib::Expander>, 32 } 33 34 impl ProcMacroSrv { expand(&mut self, task: ExpandMacro) -> Result<FlatTree, PanicMessage>35 pub fn expand(&mut self, task: ExpandMacro) -> Result<FlatTree, PanicMessage> { 36 let expander = self.expander(task.lib.as_ref()).map_err(|err| { 37 debug_assert!(false, "should list macros before asking to expand"); 38 PanicMessage(format!("failed to load macro: {}", err)) 39 })?; 40 41 let mut prev_env = HashMap::new(); 42 for (k, v) in &task.env { 43 prev_env.insert(k.as_str(), env::var_os(k)); 44 env::set_var(k, v); 45 } 46 47 let macro_body = task.macro_body.to_subtree(); 48 let attributes = task.attributes.map(|it| it.to_subtree()); 49 let result = expander 50 .expand(&task.macro_name, ¯o_body, attributes.as_ref()) 51 .map(|it| FlatTree::new(&it)); 52 53 for (k, _) in &task.env { 54 match &prev_env[k.as_str()] { 55 Some(v) => env::set_var(k, v), 56 None => env::remove_var(k), 57 } 58 } 59 60 result.map_err(PanicMessage) 61 } 62 list_macros( &mut self, dylib_path: &Path, ) -> Result<Vec<(String, ProcMacroKind)>, String>63 pub(crate) fn list_macros( 64 &mut self, 65 dylib_path: &Path, 66 ) -> Result<Vec<(String, ProcMacroKind)>, String> { 67 let expander = self.expander(dylib_path)?; 68 Ok(expander.list_macros()) 69 } 70 expander(&mut self, path: &Path) -> Result<&dylib::Expander, String>71 fn expander(&mut self, path: &Path) -> Result<&dylib::Expander, String> { 72 let time = fs::metadata(path).and_then(|it| it.modified()).map_err(|err| { 73 format!("Failed to get file metadata for {}: {:?}", path.display(), err) 74 })?; 75 76 Ok(match self.expanders.entry((path.to_path_buf(), time)) { 77 Entry::Vacant(v) => v.insert(dylib::Expander::new(path).map_err(|err| { 78 format!("Cannot create expander for {}: {:?}", path.display(), err) 79 })?), 80 Entry::Occupied(e) => e.into_mut(), 81 }) 82 } 83 } 84 85 pub mod cli; 86 87 #[cfg(test)] 88 mod tests; 89