From aa73023bee1aebc745188e54039d3bf567be97e3 Mon Sep 17 00:00:00 2001
From: Steven Le Rouzic <steven.lerouzic@gmail.com>
Date: Thu, 20 Feb 2025 23:47:02 +0100
Subject: Use intrusive list in logging, and add defer

---
 asl/base/BUILD.bazel     |  2 ++
 asl/base/defer.hpp       | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
 asl/base/defer_tests.cpp | 32 +++++++++++++++++++++++++++++++
 asl/base/utility.hpp     |  3 +++
 4 files changed, 87 insertions(+)
 create mode 100644 asl/base/defer.hpp
 create mode 100644 asl/base/defer_tests.cpp

(limited to 'asl/base')

diff --git a/asl/base/BUILD.bazel b/asl/base/BUILD.bazel
index 317c20b..3dc715b 100644
--- a/asl/base/BUILD.bazel
+++ b/asl/base/BUILD.bazel
@@ -4,6 +4,7 @@ cc_library(
         "annotations.hpp",
         "assert.hpp",
         "config.hpp",
+        "defer.hpp",
         "float.hpp",
         "functional.hpp",
         "integers.hpp",
@@ -28,6 +29,7 @@ cc_library(
         "//asl/types:box",
     ],
 ) for name in [
+    "defer",
     "float",
     "functional",
     "integers",
diff --git a/asl/base/defer.hpp b/asl/base/defer.hpp
new file mode 100644
index 0000000..b6d52af
--- /dev/null
+++ b/asl/base/defer.hpp
@@ -0,0 +1,50 @@
+#pragma once
+
+#include "asl/base/utility.hpp"
+#include "asl/base/functional.hpp"
+
+namespace asl
+{
+
+// @Todo Add invokable check
+template<typename Callback>
+class DeferCallback
+{
+    Callback m_callback;
+    bool     m_moved = false;
+
+public:
+    template<typename T>
+    explicit DeferCallback(T&& callback) : m_callback(ASL_FWD(callback))
+    {
+    }
+
+    ASL_DELETE_COPY(DeferCallback);
+
+    DeferCallback(DeferCallback&& other) :
+        m_callback(ASL_MOVE(other.m_callback)), m_moved(exchange(other.m_moved, true))
+    {
+    }
+
+    DeferCallback& operator=(DeferCallback&&) = delete;
+
+    ~DeferCallback()
+    {
+        if (!m_moved) { invoke(m_callback); }
+    }
+};
+
+struct DeferFactory
+{
+    // @Todo Add invokable check
+    template<typename Callback>
+    DeferCallback<Callback> operator<<(Callback&& callback) const
+    {
+        return DeferCallback<Callback>(ASL_FWD(callback));
+    }
+};
+
+} // namespace asl
+
+#define ASL_DEFER auto ASL_CONCAT(_defer_, __COUNTER__) = ::asl::DeferFactory{} <<
+
diff --git a/asl/base/defer_tests.cpp b/asl/base/defer_tests.cpp
new file mode 100644
index 0000000..b5139d5
--- /dev/null
+++ b/asl/base/defer_tests.cpp
@@ -0,0 +1,32 @@
+#include "asl/base/defer.hpp"
+#include "asl/testing/testing.hpp"
+
+ASL_TEST(defer)
+{
+    uint32_t a = 0;
+
+    {
+        ASL_DEFER [&a]() { a |= 1; };
+        ASL_TEST_EXPECT(a == 0);
+
+        {
+            ASL_DEFER [&a]() { a |= 2; };
+            ASL_DEFER [&a]() { a |= 4; };
+            ASL_TEST_EXPECT(a == 0);
+        }
+        
+        ASL_TEST_EXPECT(a == 6);
+
+        {
+            ASL_DEFER [&a]() { a |= 8; };
+            ASL_TEST_EXPECT(a == 6);
+        }
+
+        ASL_TEST_EXPECT(a == 14);
+        
+        ASL_DEFER [&a]() { a |= 16; };
+        ASL_TEST_EXPECT(a == 14);
+    }
+    
+    ASL_TEST_EXPECT(a == 31);
+}
diff --git a/asl/base/utility.hpp b/asl/base/utility.hpp
index c03554f..b3fb36b 100644
--- a/asl/base/utility.hpp
+++ b/asl/base/utility.hpp
@@ -92,4 +92,7 @@ constexpr bool is_pow2(isize_t v)
     ASL_DEFAULT_COPY(T)                             \
     ASL_DEFAULT_MOVE(T)
 
+#define ASL_CONCAT2(A, B) A##B
+#define ASL_CONCAT(A, B) ASL_CONCAT2(A, B)
+
 } // namespace asl
-- 
cgit