README.md

@@ -11,7 +11,7 @@
  * No other dependencies except STL.
  * Only lock-free or lightweight spin-lock is used.
  * Circular array is used as the underline data structure.
- * `ipc::route` supports single read and multiple write. `ipc::channel` supports multiple read and write. (**Note: currently, a channel supports up to 32 receivers, but there is no such a limit for the sender.**) 
+ * `ipc::route` supports single write and multiple read. `ipc::channel` supports multiple read and write. (**Note: currently, a channel supports up to 32 receivers, but there is no such a limit for the sender.**) 
  * Broadcasting is used by default, but user can choose any read/ write combinations.
  * No long time blind wait. (Semaphore will be used after a certain number of retries.) 
  * [Vcpkg](https://github.com/microsoft/vcpkg/blob/master/README.md) way of installation is supported. E.g. `vcpkg install cpp-ipc`

include/libipc/condition.h

@@ -26,6 +26,9 @@ class IPC_EXPORT condition {
     bool open(char const *name) noexcept;
     void close() noexcept;
 
+    void clear() noexcept;
+    static void clear_storage(char const * name) noexcept;
+
     bool wait(ipc::sync::mutex &mtx, std::uint64_t tm = ipc::invalid_value) noexcept;
     bool notify(ipc::sync::mutex &mtx) noexcept;
     bool broadcast(ipc::sync::mutex &mtx) noexcept;

include/libipc/ipc.h

@@ -19,7 +19,7 @@ enum : unsigned {
 
 template <typename Flag>
 struct IPC_EXPORT chan_impl {
-    static ipc::handle_t inited();
+    static ipc::handle_t init_first();
 
     static bool connect   (ipc::handle_t * ph, char const * name, unsigned mode);
     static bool connect   (ipc::handle_t * ph, prefix, char const * name, unsigned mode);
@@ -29,8 +29,16 @@ struct IPC_EXPORT chan_impl {
 
     static char const * name(ipc::handle_t h);
 
-    static std::size_t recv_count(ipc::handle_t h);
-    static bool wait_for_recv(ipc::handle_t h, std::size_t r_count, std::uint64_t tm);
+    // Release memory without waiting for the connection to disconnect.
+    static void release(ipc::handle_t h) noexcept;
+
+    // Force cleanup of all shared memory storage that handles depend on.
+    static void clear(ipc::handle_t h) noexcept;
+    static void clear_storage(char const * name) noexcept;
+    static void clear_storage(prefix, char const * name) noexcept;
+
+    static std::size_t recv_count   (ipc::handle_t h);
+    static bool        wait_for_recv(ipc::handle_t h, std::size_t r_count, std::uint64_t tm);
 
     static bool   send(ipc::handle_t h, void const * data, std::size_t size, std::uint64_t tm);
     static buff_t recv(ipc::handle_t h, std::uint64_t tm);
@@ -44,7 +52,7 @@ class chan_wrapper {
 private:
     using detail_t = chan_impl<Flag>;
 
-    ipc::handle_t h_ = detail_t::inited();
+    ipc::handle_t h_ = detail_t::init_first();
     unsigned mode_   = ipc::sender;
     bool connected_  = false;
 
@@ -83,6 +91,28 @@ class chan_wrapper {
         return detail_t::name(h_);
     }
 
+    // Release memory without waiting for the connection to disconnect.
+    void release() noexcept {
+        detail_t::release(h_);
+        h_ = nullptr;
+    }
+
+    // Clear shared memory files under opened handle.
+    void clear() noexcept {
+        detail_t::clear(h_);
+        h_ = nullptr;
+    }
+
+    // Clear shared memory files under a specific name.
+    static void clear_storage(char const * name) noexcept {
+        detail_t::clear_storage(name);
+    }
+
+    // Clear shared memory files under a specific name with a prefix.
+    static void clear_storage(prefix pref, char const * name) noexcept {
+        detail_t::clear_storage(pref, name);
+    }
+
     ipc::handle_t handle() const noexcept {
         return h_;
     }

include/libipc/mutex.h

@@ -26,6 +26,9 @@ class IPC_EXPORT mutex {
     bool open(char const *name) noexcept;
     void close() noexcept;
 
+    void clear() noexcept;
+    static void clear_storage(char const * name) noexcept;
+
     bool lock(std::uint64_t tm = ipc::invalid_value) noexcept;
     bool try_lock() noexcept(false); // std::system_error
     bool unlock() noexcept;

include/libipc/pool_alloc.h

@@ -11,8 +11,8 @@ namespace mem {
 
 class IPC_EXPORT pool_alloc {
 public:
-    static void* alloc(std::size_t size);
-    static void  free (void* p, std::size_t size);
+    static void* alloc(std::size_t size) noexcept;
+    static void  free (void* p, std::size_t size) noexcept;
 };
 
 ////////////////////////////////////////////////////////////////

include/libipc/rw_lock.h

@@ -6,6 +6,7 @@
 #include <limits>
 #include <type_traits>
 #include <utility>
+#include <cstdint>
 
 ////////////////////////////////////////////////////////////////
 /// Gives hint to processor that improves performance of spin-wait loops.
@@ -98,7 +99,7 @@ inline void sleep(K& k) {
 namespace ipc {
 
 class spin_lock {
-    std::atomic<unsigned> lc_ { 0 };
+    std::atomic<std::uint32_t> lc_ { 0 };
 
 public:
     void lock(void) noexcept {
@@ -113,13 +114,13 @@ class spin_lock {
 };
 
 class rw_lock {
-    using lc_ui_t = unsigned;
+    using lc_ui_t = std::uint32_t;
 
     std::atomic<lc_ui_t> lc_ { 0 };
 
     enum : lc_ui_t {
-        w_mask = (std::numeric_limits<std::make_signed_t<lc_ui_t>>::max)(), // b 0111 1111
-        w_flag = w_mask + 1                                                 // b 1000 0000
+        w_mask = (std::numeric_limits<std::make_signed_t<lc_ui_t>>::max)(), // b 0111 1111 ...
+        w_flag = w_mask + 1                                                 // b 1000 0000 ...
     };
 
 public:

include/libipc/semaphore.h

@@ -25,6 +25,9 @@ class IPC_EXPORT semaphore {
     bool open(char const *name, std::uint32_t count = 0) noexcept;
     void close() noexcept;
 
+    void clear() noexcept;
+    static void clear_storage(char const * name) noexcept;
+
     bool wait(std::uint64_t tm = ipc::invalid_value) noexcept;
     bool post(std::uint32_t count = 1) noexcept;
 

include/libipc/shm.h

@@ -17,9 +17,9 @@ enum : unsigned {
 
 IPC_EXPORT id_t         acquire(char const * name, std::size_t size, unsigned mode = create | open);
 IPC_EXPORT void *       get_mem(id_t id, std::size_t * size);
-IPC_EXPORT std::int32_t release(id_t id);
-IPC_EXPORT void         remove (id_t id);
-IPC_EXPORT void         remove (char const * name);
+IPC_EXPORT std::int32_t release(id_t id) noexcept;
+IPC_EXPORT void         remove (id_t id) noexcept;
+IPC_EXPORT void         remove (char const * name) noexcept;
 
 IPC_EXPORT std::int32_t get_ref(id_t id);
 IPC_EXPORT void sub_ref(id_t id);
@@ -45,6 +45,10 @@ class IPC_EXPORT handle {
     bool acquire(char const * name, std::size_t size, unsigned mode = create | open);
     std::int32_t release();
 
+    // Clean the handle file.
+    void clear() noexcept;
+    static void clear_storage(char const * name) noexcept;
+
     void* get() const;
 
     void attach(id_t);

src/CMakeLists.txt

@@ -1,5 +1,7 @@
 project(ipc)
 
+set (PACKAGE_VERSION 1.3.0)
+
 aux_source_directory(${LIBIPC_PROJECT_DIR}/src/libipc SRC_FILES)
 aux_source_directory(${LIBIPC_PROJECT_DIR}/src/libipc/sync SRC_FILES)
 aux_source_directory(${LIBIPC_PROJECT_DIR}/src/libipc/platform SRC_FILES)
@@ -34,11 +36,13 @@ set_target_properties(${PROJECT_NAME}
 # set version
 set_target_properties(${PROJECT_NAME}
     PROPERTIES
-    VERSION 1.2.0
+    VERSION ${PACKAGE_VERSION}
     SOVERSION 3)
 
 target_include_directories(${PROJECT_NAME}
-  PUBLIC  ${LIBIPC_PROJECT_DIR}/include
+  PUBLIC  
+    "$<BUILD_INTERFACE:${LIBIPC_PROJECT_DIR}/include>"
+    "$<INSTALL_INTERFACE:include>"
   PRIVATE ${LIBIPC_PROJECT_DIR}/src
           $<$<BOOL:UNIX>:${LIBIPC_PROJECT_DIR}/src/libipc/platform/linux>)
 
@@ -50,6 +54,28 @@ endif()
 
 install(
   TARGETS ${PROJECT_NAME}
+  EXPORT cpp-ipc-targets
   RUNTIME DESTINATION bin
   LIBRARY DESTINATION lib
   ARCHIVE DESTINATION lib)
+
+install(EXPORT cpp-ipc-targets
+	FILE cpp-ipc-targets.cmake
+	NAMESPACE cpp-ipc::
+	DESTINATION share/cpp-ipc
+)
+
+file(WRITE "${CMAKE_CURRENT_BINARY_DIR}/cpp-ipc-config.cmake.in"
+[[include(CMakeFindDependencyMacro)
+include("${CMAKE_CURRENT_LIST_DIR}/cpp-ipc-targets.cmake")
+]])
+configure_file("${CMAKE_CURRENT_BINARY_DIR}/cpp-ipc-config.cmake.in" "${CMAKE_CURRENT_BINARY_DIR}/cpp-ipc-config.cmake" @ONLY)
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/cpp-ipc-config.cmake DESTINATION share/cpp-ipc)
+
+include(CMakePackageConfigHelpers)
+write_basic_package_version_file(
+	cppIpcConfigVersion.cmake
+	VERSION ${PACKAGE_VERSION}
+	COMPATIBILITY AnyNewerVersion
+)
+install(FILES ${CMAKE_CURRENT_BINARY_DIR}/cppIpcConfigVersion.cmake DESTINATION share/cpp-ipc)

src/libipc/circ/elem_def.h

@@ -60,7 +60,7 @@ class conn_head<P, true> : public conn_head_base {
         for (unsigned k = 0;; ipc::yield(k)) {
             cc_t curr = this->cc_.load(std::memory_order_acquire);
             cc_t next = curr | (curr + 1); // find the first 0, and set it to 1.
-            if (next == 0) {
+            if (next == curr) {
                 // connection-slot is full.
                 return 0;
             }
@@ -74,6 +74,10 @@ class conn_head<P, true> : public conn_head_base {
         return this->cc_.fetch_and(~cc_id, std::memory_order_acq_rel) & ~cc_id;
     }
 
+    bool connected(cc_t cc_id) const noexcept {
+        return (this->connections() & cc_id) != 0;
+    }
+
     std::size_t conn_count(std::memory_order order = std::memory_order_acquire) const noexcept {
         cc_t cur = this->cc_.load(order);
         cc_t cnt; // accumulates the total bits set in cc
@@ -100,6 +104,11 @@ class conn_head<P, false> : public conn_head_base {
         }
     }
 
+    bool connected(cc_t cc_id) const noexcept {
+        // In non-broadcast mode, connection tags are only used for counting.
+        return (this->connections() != 0) && (cc_id != 0);
+    }
+
     std::size_t conn_count(std::memory_order order = std::memory_order_acquire) const noexcept {
         return this->connections(order);
     }

src/libipc/ipc.cpp

@@ -136,6 +136,22 @@ struct conn_info_head {
         }
     }
 
+    void clear() noexcept {
+        cc_waiter_.clear();
+        wt_waiter_.clear();
+        rd_waiter_.clear();
+        acc_h_.clear();
+    }
+
+    static void clear_storage(char const * prefix, char const * name) noexcept {
+        auto p = ipc::make_string(prefix);
+        auto n = ipc::make_string(name);
+        ipc::detail::waiter::clear_storage(ipc::make_prefix(p, {"CC_CONN__", n}).c_str());
+        ipc::detail::waiter::clear_storage(ipc::make_prefix(p, {"WT_CONN__", n}).c_str());
+        ipc::detail::waiter::clear_storage(ipc::make_prefix(p, {"RD_CONN__", n}).c_str());
+        ipc::shm::handle::clear_storage(ipc::make_prefix(p, {"AC_CONN__", n}).c_str());
+    }
+
     void quit_waiting() {
         cc_waiter_.quit_waiting();
         wt_waiter_.quit_waiting();
@@ -379,13 +395,27 @@ struct queue_generator {
             conn_info_head::init();
             if (!que_.valid()) {
                 que_.open(ipc::make_prefix(prefix_, {
-                          "QU_CONN__",
-                          ipc::to_string(DataSize), "__",
-                          ipc::to_string(AlignSize), "__", 
-                          this->name_}).c_str());
+                          "QU_CONN__", 
+                          this->name_, 
+                          "__", ipc::to_string(DataSize), 
+                          "__", ipc::to_string(AlignSize)}).c_str());
             }
         }
 
+        void clear() noexcept {
+            que_.clear();
+            conn_info_head::clear();
+        }
+
+        static void clear_storage(char const * prefix, char const * name) noexcept {
+            queue_t::clear_storage(ipc::make_prefix(ipc::make_string(prefix), {
+                                   "QU_CONN__", 
+                                   ipc::make_string(name), 
+                                   "__", ipc::to_string(DataSize), 
+                                   "__", ipc::to_string(AlignSize)}).c_str());
+            conn_info_head::clear_storage(prefix, name);
+        }
+
         void disconnect_receiver() {
             bool dis = que_.disconnect();
             this->quit_waiting();
@@ -459,8 +489,7 @@ static bool reconnect(ipc::handle_t * ph, bool start_to_recv) {
     return que->ready_sending();
 }
 
-static void destroy(ipc::handle_t h) {
-    disconnect(h);
+static void destroy(ipc::handle_t h) noexcept {
     ipc::mem::free(info_of(h));
 }
 
@@ -598,7 +627,10 @@ static ipc::buff_t recv(ipc::handle_t h, std::uint64_t tm) {
     for (;;) {
         // pop a new message
         typename queue_t::value_t msg {};
-        if (!wait_for(inf->rd_waiter_, [que, &msg] {
+        if (!wait_for(inf->rd_waiter_, [que, &msg, &h] {
+                if (!que->connected()) {
+                    reconnect(&h, true);
+                }
                 return !que->pop(msg);
             }, tm)) {
             // pop failed, just return.
@@ -703,7 +735,7 @@ using policy_t = ipc::policy::choose<ipc::circ::elem_array, Flag>;
 namespace ipc {
 
 template <typename Flag>
-ipc::handle_t chan_impl<Flag>::inited() {
+ipc::handle_t chan_impl<Flag>::init_first() {
     ipc::detail::waiter::init();
     return nullptr;
 }
@@ -730,6 +762,12 @@ void chan_impl<Flag>::disconnect(ipc::handle_t h) {
 
 template <typename Flag>
 void chan_impl<Flag>::destroy(ipc::handle_t h) {
+    disconnect(h);
+    detail_impl<policy_t<Flag>>::destroy(h);
+}
+
+template <typename Flag>
+void chan_impl<Flag>::release(ipc::handle_t h) noexcept {
     detail_impl<policy_t<Flag>>::destroy(h);
 }
 
@@ -739,6 +777,27 @@ char const * chan_impl<Flag>::name(ipc::handle_t h) {
     return (info == nullptr) ? nullptr : info->name_.c_str();
 }
 
+template <typename Flag>
+void chan_impl<Flag>::clear(ipc::handle_t h) noexcept {
+    disconnect(h);
+    using conn_info_t = typename detail_impl<policy_t<Flag>>::conn_info_t;
+    auto conn_info_p = static_cast<conn_info_t *>(h);
+    if (conn_info_p == nullptr) return;
+    conn_info_p->clear();
+    destroy(h);
+}
+
+template <typename Flag>
+void chan_impl<Flag>::clear_storage(char const * name) noexcept {
+    chan_impl<Flag>::clear_storage({nullptr}, name);
+}
+
+template <typename Flag>
+void chan_impl<Flag>::clear_storage(prefix pref, char const * name) noexcept {
+    using conn_info_t = typename detail_impl<policy_t<Flag>>::conn_info_t;
+    conn_info_t::clear_storage(pref.str, name);
+}
+
 template <typename Flag>
 std::size_t chan_impl<Flag>::recv_count(ipc::handle_t h) {
     return detail_impl<policy_t<Flag>>::recv_count(h);