From aa46a936f29f219fdff8a87f2d2a3307e1208726 Mon Sep 17 00:00:00 2001
From: "Chris West (Faux)" <git@goeswhere.com>
Date: Thu, 13 Jul 2017 13:38:48 +0100
Subject: [PATCH] give in and lazy_singleton the cache

---
 Cargo.toml    |  1 +
 apt-c/lib.cpp |  2 +-
 src/lib.rs    | 13 ++++++-------
 src/raw.rs    | 34 ++++++++++++++++++++--------------
 src/sane.rs   | 21 +++++----------------
 5 files changed, 33 insertions(+), 38 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index ff6ee38..70f56e0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,4 +4,5 @@ version = "0.1.0"
 authors = ["Chris West (Faux) <git@goeswhere.com>"]
 
 [dependencies]
+lazy_static = "0.2.8"
 libc = "0.2.26"
diff --git a/apt-c/lib.cpp b/apt-c/lib.cpp
index 841874a..5d3e4a3 100644
--- a/apt-c/lib.cpp
+++ b/apt-c/lib.cpp
@@ -26,7 +26,6 @@ extern "C" {
     void init_config_system();
 
     PCache *pkg_cache_create();
-    void pkg_cache_release(PCache *cache);
 
     PPkgIterator *pkg_cache_pkg_iter(PCache *cache);
     PPkgIterator *pkg_cache_find_name(PCache *cache, const char *name);
@@ -88,6 +87,7 @@ PPkgIterator *pkg_cache_find_name_arch(PCache *cache, const char *name, const ch
     return wrapper;
 }
 
+// TODO: we don't expose this so we always leak the wrapper.
 void pkg_iter_release(PPkgIterator *wrapper) {
     delete wrapper;
 }
diff --git a/src/lib.rs b/src/lib.rs
index bdfa34d..3df863f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,4 @@
+#[macro_use] extern crate lazy_static;
 extern crate libc;
 
 mod raw;
@@ -10,17 +11,15 @@ pub use sane::Cache;
 mod tests {
     use super::*;
 
-//    #[test]
-    fn list_all() {
-        let mut cache = Cache::new();
-        for name in cache.iter().map(|item| item.pretty_print()) {
-            println!("{}", name);
-        }
+    #[test]
+    fn pretty_print_all() {
+        let mut cache = Cache::get_singleton();
+        assert!(cache.iter().map(|item| item.pretty_print()).count() > 0);
     }
 
     #[test]
     fn find_a_package() {
-        let mut cache = Cache::new();
+        let mut cache = Cache::get_singleton();
         {
             let iter = cache.find_by_name("apt");
             assert!(!iter.is_empty());
diff --git a/src/raw.rs b/src/raw.rs
index cd382a0..af62516 100644
--- a/src/raw.rs
+++ b/src/raw.rs
@@ -15,10 +15,7 @@ pub type PPkgIterator = *mut c_void;
 extern {
     /// Must be called exactly once, before anything else?
     fn init_config_system();
-
-    /// I'm not convinced you can even call this multiple times.
-    pub fn pkg_cache_create() -> PCache;
-    pub fn pkg_cache_release(cache: PCache);
+    fn pkg_cache_create() -> PCache;
 
     pub fn pkg_cache_pkg_iter(cache: PCache) -> PPkgIterator;
     pub fn pkg_cache_find_name(cache: PCache, name: *const c_char) -> PPkgIterator;
@@ -34,14 +31,23 @@ extern {
     pub fn pkg_iter_pretty(cache: PCache, iterator: PPkgIterator) -> *mut c_char;
 }
 
-static mut INIT_CONFIG_CALLED: bool = false;
-
-pub unsafe fn init_config_system_once() {
-    if INIT_CONFIG_CALLED {
-        return;
-    }
-
-    INIT_CONFIG_CALLED = true;
-
-    init_config_system()
+pub fn pkg_cache_get() -> PCache {
+    CACHE.ptr
+}
+
+struct CacheHolder {
+    ptr: PCache
+}
+
+unsafe impl Sync for CacheHolder {}
+
+lazy_static! {
+    static ref CACHE: CacheHolder = {
+        unsafe {
+            init_config_system();
+            CacheHolder {
+                ptr: pkg_cache_create()
+            }
+        }
+    };
 }
diff --git a/src/sane.rs b/src/sane.rs
index 5db1102..423ff7e 100644
--- a/src/sane.rs
+++ b/src/sane.rs
@@ -3,28 +3,17 @@ use std::ffi;
 use libc;
 use raw;
 
-// Probably not cloneable / copyable.
-/// You might only be able to create one of these per process.
+/// A reference to the package cache singleton.
+/// Basically just a collection of related methods.
 #[derive(Debug)]
 pub struct Cache {
     ptr: raw::PCache
 }
 
-impl Drop for Cache {
-    fn drop(&mut self) {
-        unsafe {
-            raw::pkg_cache_release(self.ptr)
-        }
-    }
-}
-
 impl Cache {
-    pub fn new() -> Cache {
-        unsafe {
-            raw::init_config_system_once();
-            Cache {
-                ptr: raw::pkg_cache_create()
-            }
+    pub fn get_singleton() -> Cache {
+        Cache {
+            ptr: raw::pkg_cache_get()
         }
     }