From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Sun, 27 Sep 2020 11:29:06 +0000 (+0100)
Subject: try rental for lib load guard, nice
X-Git-Tag: otter-0.2.0~862
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=7261c3faf0a6607a887b4b5e2d8b2758f8d37ffb;p=otter.git

try rental for lib load guard, nice

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
---

diff --git a/src/global.rs b/src/global.rs
index 341008d6..cee4af1f 100644
--- a/src/global.rs
+++ b/src/global.rs
@@ -178,7 +178,7 @@ pub struct Global {
   config  : RwLock<Arc<ServerConfig>>,
   dirty   : Mutex<VecDeque<InstanceRef>>,
   save_area_lock : Mutex<Option<File>>,
-  pub shapelibs : RwLock<HashMap<String,shapelib::Contents>>,
+  pub shapelibs : RwLock<shapelib::Registry>,
 }
 
 #[derive(Debug)]
diff --git a/src/imports.rs b/src/imports.rs
index 943632e5..f70e8fed 100644
--- a/src/imports.rs
+++ b/src/imports.rs
@@ -10,7 +10,7 @@ pub use std::fmt::Formatter;
 pub use std::fmt::{self,Display,Debug};
 pub use std::thread;
 pub use std::time::Duration;
-pub use std::sync::{Arc,Mutex,MutexGuard,RwLock,Condvar};
+pub use std::sync::{Arc,Mutex,MutexGuard,RwLock,RwLockReadGuard,Condvar};
 pub use std::collections::{HashMap,hash_map,HashSet};
 pub use std::borrow::Borrow;
 pub use std::convert::{TryFrom,TryInto};
diff --git a/src/shapelib.rs b/src/shapelib.rs
index 0d9dd164..73ad3c7b 100644
--- a/src/shapelib.rs
+++ b/src/shapelib.rs
@@ -11,6 +11,8 @@ pub use crate::imports::*;
 //  Item           } once loaded and part of a game,
 //  Outline        }  no Arc's as we serialise/deserialize during save/load
 
+pub type Registry = HashMap<String,shapelib::Contents>;
+
 #[derive(Debug)]
 pub struct Contents {
   libname: String,
@@ -184,11 +186,20 @@ impl Piece for Item {
   fn itemname(&self) -> &str { &self.itemname }
 }
 
+use rental::common::RentRef;
+
+#[throws(SpecError)]
+pub fn libs_lookup(libname: &str) -> RentRef<RwLockReadGuard<'static, Registry>, Contents> {
+  let libs = GLOBAL.shapelibs.read().unwrap();
+  RentRef::try_new(libs,|libs|Ok({
+    libs.get(libname).ok_or(SE::LibraryNotFound)?
+  })).map_err::<SpecError,_>(|e:rental::RentalError<_,_>|e.0)?
+}
+
 impl ItemSpec {
   #[throws(SpecError)]
   pub fn load(&self) -> Box<dyn Piece> {
-    let libs = GLOBAL.shapelibs.read().unwrap(); 
-    let lib = libs.get(&self.lib).ok_or(SE::LibraryNotFound)?;
+    let lib = libs_lookup(&self.lib)?;
     let idata = lib.items.get(&self.item).ok_or(SE::LibraryItemNotFound)?;
     lib.load1(idata, &self.item)?
   }