Synchronize with SHM branch

.gitignore

@@ -0,0 +1,5 @@
+build
+install
+.cache
+log
+.vscode

rmw_zenoh_cpp/CMakeLists.txt

@@ -7,6 +7,8 @@ if(NOT CMAKE_CXX_STANDARD)
   set(CMAKE_CXX_STANDARD_REQUIRED ON)
 endif()
 
+set(RMW_ZENOH_BUILD_WITH_SHARED_MEMORY OFF CACHE BOOL "Compile Zenoh RMW with Shared Memory support")
+
 if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
   add_compile_options(-Wall -Wextra -Wpedantic)
 endif()
@@ -74,6 +76,14 @@ target_compile_definitions(rmw_zenoh_cpp
     RMW_VERSION_PATCH=${rmw_VERSION_PATCH}
 )
 
+if(${RMW_ZENOH_BUILD_WITH_SHARED_MEMORY})
+  target_compile_definitions(rmw_zenoh_cpp
+    PRIVATE
+      RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+  )
+endif()
+
+
 ament_export_targets(export_rmw_zenoh_cpp)
 
 register_rmw_implementation(

rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_ROUTER_CONFIG.json5

@@ -236,7 +236,7 @@
     },
     /// Shared memory configuration
     shared_memory: {
-      enabled: false,
+      enabled: true,
     },
     /// Access control configuration
     auth: {

rmw_zenoh_cpp/config/DEFAULT_RMW_ZENOH_SESSION_CONFIG.json5

@@ -239,7 +239,7 @@
     },
     /// Shared memory configuration
     shared_memory: {
-      enabled: false,
+      enabled: true,
     },
     /// Access control configuration
     auth: {

rmw_zenoh_cpp/src/detail/zenoh_config.cpp

@@ -42,6 +42,12 @@ static const std::unordered_map<ConfigurableEntity,
 };
 
 static const char * router_check_attempts_envar = "ZENOH_ROUTER_CHECK_ATTEMPTS";
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+static const char * zenoh_shm_alloc_size_envar = "ZENOH_SHM_ALLOC_SIZE";
+static const size_t zenoh_shm_alloc_size_default = 1 * 1024 * 1024;
+static const char * zenoh_shm_message_size_threshold_envar = "ZENOH_SHM_MESSAGE_SIZE_THRESHOLD";
+static const size_t zenoh_shm_message_size_threshold_default = 2 * 1024;
+#endif
 
 rmw_ret_t _get_z_config(
   const char * envar_name,
@@ -123,4 +129,64 @@ std::optional<uint64_t> zenoh_router_check_attempts()
   // If unset, check indefinitely.
   return default_value;
 }
+
+
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+///=============================================================================
+size_t zenoh_shm_alloc_size()
+{
+  const char * envar_value;
+
+  if (NULL != rcutils_get_env(zenoh_shm_alloc_size_envar, &envar_value)) {
+    RMW_ZENOH_LOG_ERROR_NAMED(
+      "rmw_zenoh_cpp", "Envar %s cannot be read. Report this bug.",
+      zenoh_shm_alloc_size_envar);
+    return zenoh_shm_alloc_size_default;
+  }
+
+  // If the environment variable contains a value, handle it accordingly.
+  if (envar_value[0] != '\0') {
+    const auto read_value = std::strtoull(envar_value, nullptr, 10);
+    if (read_value > 0) {
+      if (read_value > std::numeric_limits<size_t>::max()) {
+        RMW_ZENOH_LOG_ERROR_NAMED(
+          "rmw_zenoh_cpp", "Envar %s: value is too large!",
+          zenoh_shm_alloc_size_envar);
+      } else {
+        return read_value;
+      }
+    }
+  }
+
+  return zenoh_shm_alloc_size_default;
+}
+///=============================================================================
+size_t zenoh_shm_message_size_threshold()
+{
+  const char * envar_value;
+
+  if (NULL != rcutils_get_env(zenoh_shm_message_size_threshold_envar, &envar_value)) {
+    RMW_ZENOH_LOG_ERROR_NAMED(
+      "rmw_zenoh_cpp", "Envar %s cannot be read. Report this bug.",
+      zenoh_shm_message_size_threshold_envar);
+    return zenoh_shm_message_size_threshold_default;
+  }
+
+  // If the environment variable contains a value, handle it accordingly.
+  if (envar_value[0] != '\0') {
+    const auto read_value = std::strtoull(envar_value, nullptr, 10);
+    if (read_value > 0) {
+      if (read_value > std::numeric_limits<size_t>::max()) {
+        RMW_ZENOH_LOG_ERROR_NAMED(
+          "rmw_zenoh_cpp", "Envar %s: value is too large!",
+          zenoh_shm_message_size_threshold_envar);
+      } else {
+        return read_value;
+      }
+    }
+  }
+
+  return zenoh_shm_message_size_threshold_default;
+}
+#endif
 }  // namespace rmw_zenoh_cpp

rmw_zenoh_cpp/src/detail/zenoh_config.hpp

@@ -57,6 +57,26 @@ rmw_ret_t get_z_config(const ConfigurableEntity & entity, z_owned_config_t * con
 /// @return The number of times to try connecting to a zenoh router and
 ///   std::nullopt if establishing a connection to a router is not required.
 std::optional<uint64_t> zenoh_router_check_attempts();
+
+#ifdef RMW_ZENOH_BUILD_WITH_SHARED_MEMORY
+///=============================================================================
+/// Get the amount of shared memory to be pre-allocated for Zenoh SHM operation
+/// based on the environment variable ZENOH_SHM_ALLOC_SIZE.
+/// @details The behavior is as follows:
+///   - If not set or <= 0, the default value of 1MB is returned.
+///   - Else value of environemnt variable is returned.
+/// @return The amount of shared memory to be pre-allocated for Zenoh SHM operation
+size_t zenoh_shm_alloc_size();
+///=============================================================================
+/// Message size threshold for implicit SHM optimization based on the environment
+/// variable ZENOH_SHM_ALLOC_SIZE.
+/// Messages smaller than this threshold will not be forwarded through Zenoh SHM
+/// @details The behavior is as follows:
+///   - If not set or <= 0, the default value of 2KB is returned.
+///   - Else value of environemnt variable is returned.
+/// @return The amount of shared memory to be pre-allocated for Zenoh SHM operation
+size_t zenoh_shm_message_size_threshold();
+#endif
 }  // namespace rmw_zenoh_cpp
 
 #endif  // DETAIL__ZENOH_CONFIG_HPP_