ssl: use a common helper to generate new ex data indexes, switch NPN to a lazyref

Rather than having the verification data idx generation and NPN use
there own (similar) impls to generate indexes with destructors, unify
them.

Make NPNs use of indexes more idomatic by storing the index in a
lazyref rather than having a function with static data members.

1 files changed, 17 insertions, 33 deletions

diff --git a/openssl/src/ssl/mod.rs b/openssl/src/ssl/mod.rs
index 2163891d..1123b3d0 100644
--- a/openssl/src/ssl/mod.rs
+++ b/openssl/src/ssl/mod.rs
@@ -170,49 +170,33 @@ lazy_static! {
 // Registers a destructor for the data which will be called
 // when context is freed
 fn get_verify_data_idx<T: Any + 'static>() -> c_int {
-    extern fn free_data_box<T>(_parent: *mut c_void, ptr: *mut c_void,
-                               _ad: *mut ffi::CRYPTO_EX_DATA, _idx: c_int,
-                               _argl: c_long, _argp: *mut c_void) {
-        if ptr != 0 as *mut _ {
-            let _: Box<T> = unsafe { mem::transmute(ptr) };
-        }
-    }
-
     *INDEXES.lock().unwrap().entry(TypeId::of::<T>()).or_insert_with(|| {
-        unsafe {
-            let f: ffi::CRYPTO_EX_free = free_data_box::<T>;
-            let idx = ffi::SSL_CTX_get_ex_new_index(0, ptr::null(), None, None, Some(f));
-            assert!(idx >= 0);
-            idx
-        }
+        get_new_idx::<T>()
     })
 }
 
-/// Creates a static index for the list of NPN protocols.
-/// Registers a destructor for the data which will be called
-/// when the context is freed.
 #[cfg(feature = "npn")]
-fn get_npn_protos_idx() -> c_int {
-    static mut NPN_PROTOS_IDX: c_int = -1;
-    static mut INIT: Once = ONCE_INIT;
+lazy_static! {
+    static ref NPN_PROTOS_IDX: c_int = get_new_idx::<Vec<u8>>();
+}
 
-    extern fn free_data_box(_parent: *mut c_void, ptr: *mut c_void,
+/// Determine a new index to use for SSL CTX ex data.
+/// Registers a destruct for the data which will be called by openssl when the context is freed.
+fn get_new_idx<T>() -> c_int {
+    extern fn free_data_box<T>(_parent: *mut c_void, ptr: *mut c_void,
                             _ad: *mut ffi::CRYPTO_EX_DATA, _idx: c_int,
                             _argl: c_long, _argp: *mut c_void) {
         if !ptr.is_null() {
-            let _: Box<Vec<u8>> = unsafe { mem::transmute(ptr) };
+            let _: Box<T> = unsafe { mem::transmute(ptr) };
         }
     }
 
     unsafe {
-        INIT.call_once(|| {
-            let f: ffi::CRYPTO_EX_free = free_data_box;
-            let idx = ffi::SSL_CTX_get_ex_new_index(0, ptr::null(), None,
-                                                    None, Some(f));
-            assert!(idx >= 0);
-            NPN_PROTOS_IDX = idx;
-        });
-        NPN_PROTOS_IDX
+        let f: ffi::CRYPTO_EX_free = free_data_box::<T>;
+        let idx = ffi::SSL_CTX_get_ex_new_index(0, ptr::null(), None,
+                                                None, Some(f));
+        assert!(idx >= 0);
+        idx
     }
 }
 
@@ -279,7 +263,7 @@ extern fn raw_next_proto_select_cb(ssl: *mut ffi::SSL,
         // First, get the list of protocols (that the client should support) saved in the context
         // extra data.
         let ssl_ctx = ffi::SSL_get_SSL_CTX(ssl);
-        let protocols = ffi::SSL_CTX_get_ex_data(ssl_ctx, get_npn_protos_idx());
+        let protocols = ffi::SSL_CTX_get_ex_data(ssl_ctx, *NPN_PROTOS_IDX);
         let protocols: &Vec<u8> = mem::transmute(protocols);
         // Prepare the client list parameters to be passed to the OpenSSL function...
         let client = protocols.as_ptr();
@@ -306,7 +290,7 @@ extern fn raw_next_protos_advertise_cb(ssl: *mut ffi::SSL,
     unsafe {
         // First, get the list of (supported) protocols saved in the context extra data.
         let ssl_ctx = ffi::SSL_get_SSL_CTX(ssl);
-        let protocols = ffi::SSL_CTX_get_ex_data(ssl_ctx, get_npn_protos_idx());
+        let protocols = ffi::SSL_CTX_get_ex_data(ssl_ctx, *NPN_PROTOS_IDX);
         if protocols.is_null() {
             *out = b"".as_ptr();
             *outlen = 0;
@@ -543,7 +527,7 @@ impl SslContext {
         unsafe {
             // Attach the protocol list to the OpenSSL context structure,
             // so that we can refer to it within the callback.
-            ffi::SSL_CTX_set_ex_data(self.ctx, get_npn_protos_idx(),
+            ffi::SSL_CTX_set_ex_data(self.ctx, *NPN_PROTOS_IDX,
                                      mem::transmute(protocols));
             // Now register the callback that performs the default protocol
             // matching based on the client-supported list of protocols that