From 7ad7e3861822131e494d270170eb36cb006c26e1 Mon Sep 17 00:00:00 2001
From: Andrei Avram <6795248+andreiavrammsd@users.noreply.github.com>
Date: Sun, 11 Aug 2024 09:21:21 +0300
Subject: [PATCH] Return reference from iterator (#40)

Fixes blocking iterator by returning (const) reference type from the dereference operator.
---
 .vscode/settings.json                 |  2 +-
 CMakeLists.txt                        |  2 +-
 examples/cmake-project/CMakeLists.txt |  2 +-
 include/msd/blocking_iterator.hpp     | 24 ++++++++++++------------
 tests/blocking_iterator_test.cpp      |  2 +-
 5 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/.vscode/settings.json b/.vscode/settings.json
index f5f323b..29e6e34 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -4,7 +4,7 @@
         "-Dcpp_channel_build_tests=ON"
     ],
     "editor.codeActionsOnSave": {
-        "source.fixAll": true
+        "source.fixAll": "explicit"
     },
     "editor.formatOnSave": true,
     "clang-format.executable": "clang-format",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ee9854..b1be169 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.12)
 project(cpp_channel)
-set(PROJECT_VERSION 0.8.2)
+set(PROJECT_VERSION 0.8.3)
 
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED YES)
diff --git a/examples/cmake-project/CMakeLists.txt b/examples/cmake-project/CMakeLists.txt
index 52de5b1..44d6b94 100644
--- a/examples/cmake-project/CMakeLists.txt
+++ b/examples/cmake-project/CMakeLists.txt
@@ -14,7 +14,7 @@ target_link_libraries(cmake_project)
 
 include(FetchContent)
 if (NOT channel_POPULATED)
-    FetchContent_Declare(channel URL https://github.com/andreiavrammsd/cpp-channel/archive/v0.8.1.zip)
+    FetchContent_Declare(channel URL https://github.com/andreiavrammsd/cpp-channel/archive/v0.8.3.zip)
     FetchContent_Populate(channel)
     include_directories(${channel_SOURCE_DIR}/include)
     # OR
diff --git a/include/msd/blocking_iterator.hpp b/include/msd/blocking_iterator.hpp
index 9e5c79b..251f189 100644
--- a/include/msd/blocking_iterator.hpp
+++ b/include/msd/blocking_iterator.hpp
@@ -20,9 +20,9 @@ template <typename Channel>
 class blocking_iterator {
    public:
     using value_type = typename Channel::value_type;
-    using reference = typename Channel::value_type&;
+    using reference = const typename Channel::value_type&;
 
-    explicit blocking_iterator(Channel& ch) : ch_{ch} {}
+    explicit blocking_iterator(Channel& chan) : chan_{chan} {}
 
     /**
      * Advances to next element in the channel.
@@ -32,12 +32,11 @@ class blocking_iterator {
     /**
      * Returns an element from the channel.
      */
-    value_type operator*() const
+    reference operator*()
     {
-        value_type value{};
-        ch_ >> value;
+        chan_ >> value_;
 
-        return value;
+        return value_;
     }
 
     /**
@@ -45,26 +44,27 @@ class blocking_iterator {
      */
     bool operator!=(blocking_iterator<Channel>) const
     {
-        std::unique_lock<std::mutex> lock{ch_.mtx_};
-        ch_.waitBeforeRead(lock);
+        std::unique_lock<std::mutex> lock{chan_.mtx_};
+        chan_.waitBeforeRead(lock);
 
-        return !(ch_.closed() && ch_.empty());
+        return !(chan_.closed() && chan_.empty());
     }
 
    private:
-    Channel& ch_;
+    Channel& chan_;
+    value_type value_{};
 };
 
 }  // namespace msd
 
 /**
- * @brief Output iterator specialization
+ * @brief Input iterator specialization
  */
 template <typename T>
 struct std::iterator_traits<msd::blocking_iterator<T>> {
     using value_type = typename msd::blocking_iterator<T>::value_type;
     using reference = typename msd::blocking_iterator<T>::reference;
-    using iterator_category = std::output_iterator_tag;
+    using iterator_category = std::input_iterator_tag;
 };
 
 #endif  // MSD_CHANNEL_BLOCKING_ITERATOR_HPP_
diff --git a/tests/blocking_iterator_test.cpp b/tests/blocking_iterator_test.cpp
index 19bb92c..674db82 100644
--- a/tests/blocking_iterator_test.cpp
+++ b/tests/blocking_iterator_test.cpp
@@ -12,7 +12,7 @@ TEST(ChannelIteratorTest, Traits)
 
     using iterator_traits = std::iterator_traits<iterator>;
     EXPECT_TRUE((std::is_same<iterator_traits::value_type, type>::value));
-    EXPECT_TRUE((std::is_same<iterator_traits::iterator_category, std::output_iterator_tag>::value));
+    EXPECT_TRUE((std::is_same<iterator_traits::iterator_category, std::input_iterator_tag>::value));
 }
 
 TEST(ChannelIteratorTest, Dereference)