Ext2FS: Free Ext2FSInodes when the last user releases them.

The inode cache was keeping these alive forever. Added a cute little magic
trick to Retainable that calls T::one_retain_left() when the retain count
is decremented to 1.

1 files changed, 16 insertions, 1 deletions

diff --git a/AK/Retainable.h b/AK/Retainable.h
index 05757bea7e..b14ca56a24 100644
--- a/AK/Retainable.h
+++ b/AK/Retainable.h
@@ -17,6 +17,18 @@ constexpr auto call_will_be_destroyed_if_present(...) -> FalseType
     return { };
 }
 
+template<class T>
+constexpr auto call_one_retain_left_if_present(T* object) -> decltype(object->one_retain_left(), TrueType { })
+{
+    object->one_retain_left();
+    return { };
+}
+
+constexpr auto call_one_retain_left_if_present(...) -> FalseType
+{
+    return { };
+}
+
 template<typename T>
 class Retainable {
 public:
@@ -29,9 +41,12 @@ public:
     void release()
     {
         ASSERT(m_retain_count);
-        if (!--m_retain_count) {
+        --m_retain_count;
+        if (m_retain_count == 0) {
             call_will_be_destroyed_if_present(static_cast<T*>(this));
             delete static_cast<T*>(this);
+        } else if (m_retain_count == 1) {
+            call_one_retain_left_if_present(static_cast<T*>(this));
         }
     }