Test load and lookup functionality. (#135)

Signed-off-by: Michel Hidalgo <michel@ekumenlabs.com>

rmw_implementation/CMakeLists.txt

@@ -58,12 +58,30 @@ else()
     "rmw")
   target_compile_definitions(${PROJECT_NAME}
     PUBLIC "DEFAULT_RMW_IMPLEMENTATION=${RMW_IMPLEMENTATION}")
+
+  # Causes the visibility macros to use dllexport rather than dllimport,
+  # which is appropriate when building the dll but not consuming it.
+  target_compile_definitions(${PROJECT_NAME} PRIVATE "RMW_IMPLEMENTATION_BUILDING_DLL")
+
+  if(BUILD_TESTING)
+    # Causes symbols to be exposed for tests to use.
+    target_compile_definitions(${PROJECT_NAME} PRIVATE
+      "RMW_IMPLEMENTATION_DEFAULT_VISIBILITY=RMW_IMPLEMENTATION_PUBLIC")
+  endif()
+
   configure_rmw_library(${PROJECT_NAME})
 
   ament_export_libraries(${PROJECT_NAME})
   ament_export_targets(${PROJECT_NAME})
   ament_export_dependencies(rcpputils rcutils)
 
+  if(BUILD_TESTING)
+    find_package(ament_cmake_gtest REQUIRED)
+    ament_add_gtest(test_functions test/test_functions.cpp)
+    ament_target_dependencies(test_functions rcutils rmw)
+    target_link_libraries(test_functions ${PROJECT_NAME})
+  endif()
+
   install(
     TARGETS ${PROJECT_NAME} EXPORT ${PROJECT_NAME}
     ARCHIVE DESTINATION lib

rmw_implementation/package.xml

@@ -27,6 +27,7 @@
 
   <depend>rmw_implementation_cmake</depend>
 
+  <test_depend>ament_cmake_gtest</test_depend>
   <test_depend>ament_lint_auto</test_depend>
   <test_depend>ament_lint_common</test_depend>
 

rmw_implementation/src/functions.cpp

@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "./functions.hpp"
+
 #include <cstddef>
 #include <stdexcept>
 
@@ -39,67 +41,92 @@
 #define STRINGIFY_(s) #s
 #define STRINGIFY(s) STRINGIFY_(s)
 
+std::shared_ptr<rcpputils::SharedLibrary>
+load_library()
+{
+  std::string env_var;
+  try {
+    env_var = rcpputils::get_env_var("RMW_IMPLEMENTATION");
+  } catch (const std::exception & e) {
+    RMW_SET_ERROR_MSG_WITH_FORMAT_STRING(
+      "failed to fetch RMW_IMPLEMENTATION "
+      "from environment due to %s", e.what());
+    return nullptr;
+  }
+
+  if (env_var.empty()) {
+    env_var = STRINGIFY(DEFAULT_RMW_IMPLEMENTATION);
+  }
+
+  std::string library_path;
+  try {
+    library_path = rcpputils::find_library_path(env_var);
+  } catch (const std::exception & e) {
+    RMW_SET_ERROR_MSG_WITH_FORMAT_STRING(
+      "failed to find shared library due to %s", e.what());
+    return nullptr;
+  }
+
+  if (library_path.empty()) {
+    RMW_SET_ERROR_MSG_WITH_FORMAT_STRING(
+      "failed to find shared library '%s'",
+      env_var.c_str());
+    return nullptr;
+  }
+
+  try {
+    return std::make_shared<rcpputils::SharedLibrary>(library_path.c_str());
+  } catch (const std::exception & e) {
+    RMW_SET_ERROR_MSG_WITH_FORMAT_STRING(
+      "failed to load shared library '%s' due to %s",
+      library_path.c_str(), e.what());
+    return nullptr;
+  }
+}
+
 std::shared_ptr<rcpputils::SharedLibrary>
 get_library()
 {
   static std::shared_ptr<rcpputils::SharedLibrary> lib;
-
   if (!lib) {
-    std::string env_var = rcpputils::get_env_var("RMW_IMPLEMENTATION");
-    if (env_var.empty()) {
-      env_var = STRINGIFY(DEFAULT_RMW_IMPLEMENTATION);
-    }
-    std::string library_path = rcpputils::find_library_path(env_var);
-    if (library_path.empty()) {
-      RMW_SET_ERROR_MSG(
-        ("failed to find shared library of rmw implementation. Searched " + env_var).c_str());
-      return nullptr;
-    }
-
-    try {
-      lib = std::make_shared<rcpputils::SharedLibrary>(library_path.c_str());
-    } catch (const std::runtime_error & e) {
-      RMW_SET_ERROR_MSG(
-        ("failed to load shared library of rmw implementation: " + library_path +
-        " Exception: " + std::string(e.what())).c_str());
-      return nullptr;
-    } catch (const std::bad_alloc & e) {
-      RMW_SET_ERROR_MSG(
-        ("failed to load shared library of rmw implementation " + library_path + ": " +
-        std::string(e.what())).c_str());
-      return nullptr;
-    }
+    lib = load_library();
   }
   return lib;
 }
 
 void *
-get_symbol(const char * symbol_name)
+lookup_symbol(std::shared_ptr<rcpputils::SharedLibrary> lib, const char * symbol_name)
 {
-  std::shared_ptr<rcpputils::SharedLibrary> lib = get_library();
-
   if (!lib) {
-    // error message set by get_library()
+    if (!rmw_error_is_set()) {
+      RMW_SET_ERROR_MSG("no shared library to lookup");
+    }  // else assume library loading failed
     return nullptr;
   }
 
   if (!lib->has_symbol(symbol_name)) {
-    rcutils_allocator_t allocator = rcutils_get_default_allocator();
-    char * msg = rcutils_format_string(
-      allocator,
-      "failed to resolve symbol '%s' in shared library '%s'", symbol_name,
-      lib->get_library_path().c_str());
-    if (msg) {
-      RMW_SET_ERROR_MSG(msg);
-      allocator.deallocate(msg, allocator.state);
-    } else {
-      RMW_SET_ERROR_MSG("failed to allocate memory for error message");
+    try {
+      std::string library_path = lib->get_library_path();
+      RMW_SET_ERROR_MSG_WITH_FORMAT_STRING(
+        "failed to resolve symbol '%s' in shared library '%s'",
+        symbol_name, library_path.c_str());
+    } catch (const std::runtime_error &) {
+      RMW_SET_ERROR_MSG_WITH_FORMAT_STRING(
+        "failed to resolve symbol '%s' in shared library",
+        symbol_name);
     }
     return nullptr;
   }
+
   return lib->get_symbol(symbol_name);
 }
 
+void *
+get_symbol(const char * symbol_name)
+{
+  return lookup_symbol(get_library(), symbol_name);
+}
+
 #ifdef __cplusplus
 extern "C"
 {

rmw_implementation/src/functions.hpp

@@ -0,0 +1,30 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef FUNCTIONS_HPP_
+#define FUNCTIONS_HPP_
+
+#include <memory>
+
+#include "rcpputils/shared_library.hpp"
+
+#include "./visibility_control.h"
+
+RMW_IMPLEMENTATION_DEFAULT_VISIBILITY
+std::shared_ptr<rcpputils::SharedLibrary> load_library();
+
+RMW_IMPLEMENTATION_DEFAULT_VISIBILITY
+void * lookup_symbol(std::shared_ptr<rcpputils::SharedLibrary> lib, const char * symbol_name);
+
+#endif  // FUNCTIONS_HPP_

rmw_implementation/src/visibility_control.h

@@ -0,0 +1,62 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef VISIBILITY_CONTROL_H_
+#define VISIBILITY_CONTROL_H_
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+// This logic was borrowed (then namespaced) from the examples on the gcc wiki:
+//     https://gcc.gnu.org/wiki/Visibility
+
+#if defined _WIN32 || defined __CYGWIN__
+  #ifdef __GNUC__
+    #define RMW_IMPLEMENTATION_EXPORT __attribute__ ((dllexport))
+    #define RMW_IMPLEMENTATION_IMPORT __attribute__ ((dllimport))
+  #else
+    #define RMW_IMPLEMENTATION_EXPORT __declspec(dllexport)
+    #define RMW_IMPLEMENTATION_IMPORT __declspec(dllimport)
+  #endif
+  #ifdef RMW_IMPLEMENTATION_BUILDING_DLL
+    #define RMW_IMPLEMENTATION_PUBLIC RMW_IMPLEMENTATION_EXPORT
+  #else
+    #define RMW_IMPLEMENTATION_PUBLIC RMW_IMPLEMENTATION_IMPORT
+  #endif
+  #define RMW_IMPLEMENTATION_PUBLIC_TYPE RMW_IMPLEMENTATION_PUBLIC
+  #define RMW_IMPLEMENTATION_LOCAL
+#else
+  #define RMW_IMPLEMENTATION_EXPORT __attribute__ ((visibility("default")))
+  #define RMW_IMPLEMENTATION_IMPORT
+  #if __GNUC__ >= 4
+    #define RMW_IMPLEMENTATION_PUBLIC __attribute__ ((visibility("default")))
+    #define RMW_IMPLEMENTATION_LOCAL  __attribute__ ((visibility("hidden")))
+  #else
+    #define RMW_IMPLEMENTATION_PUBLIC
+    #define RMW_IMPLEMENTATION_LOCAL
+  #endif
+  #define RMW_IMPLEMENTATION_PUBLIC_TYPE
+#endif
+
+#ifndef RMW_IMPLEMENTATION_DEFAULT_VISIBILITY
+#define RMW_IMPLEMENTATION_DEFAULT_VISIBILITY
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // VISIBILITY_CONTROL_H_

rmw_implementation/test/test_functions.cpp

@@ -0,0 +1,57 @@
+// Copyright 2020 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include <gtest/gtest.h>
+
+#include <memory>
+
+#include "rcutils/env.h"
+#include "rcutils/get_env.h"
+#include "rcutils/testing/fault_injection.h"
+
+#include "rmw/error_handling.h"
+
+#include "../src/functions.hpp"
+
+TEST(Functions, bad_load) {
+  const char * rmw_implementation = nullptr;
+  ASSERT_EQ(nullptr, rcutils_get_env("RMW_IMPLEMENTATION", &rmw_implementation));
+  EXPECT_TRUE(rcutils_set_env("RMW_IMPLEMENTATION", "not_an_rmw_implementation"));
+
+  EXPECT_EQ(nullptr, load_library());
+  EXPECT_TRUE(rmw_error_is_set());
+  rmw_reset_error();
+
+  EXPECT_TRUE(rcutils_set_env("RMW_IMPLEMENTATION", rmw_implementation));
+}
+
+TEST(Functions, nominal_load_and_lookup) {
+  std::shared_ptr<rcpputils::SharedLibrary> lib = load_library();
+  ASSERT_NE(nullptr, lib) << rmw_get_error_string().str;
+  EXPECT_NE(nullptr, lookup_symbol(lib, "rmw_init")) << rmw_get_error_string().str;
+  EXPECT_EQ(nullptr, lookup_symbol(lib, "not_an_rmw_function"));
+  EXPECT_TRUE(rmw_error_is_set());
+  rmw_reset_error();
+}
+
+TEST(Functions, load_and_lookup_with_internal_errors) {
+  RCUTILS_FAULT_INJECTION_TEST(
+  {
+    void * symbol = lookup_symbol(load_library(), "rmw_init");
+    if (!symbol) {
+      EXPECT_TRUE(rmw_error_is_set());
+      rmw_reset_error();
+    }
+  });
+}