add package resource related utility functions to cpp API (#27)

* add package resource related utility functions to cpp

these already existed in Python, see: #24

* store package name in PackageNotFoundError

ament_index_cpp/CMakeLists.txt

@@ -13,10 +13,14 @@ endif()
 find_package(ament_cmake REQUIRED)
 
 add_library(${PROJECT_NAME} SHARED
+  src/get_package_prefix.cpp
+  src/get_package_share_directory.cpp
+  src/get_packages_with_prefixes.cpp
   src/get_resource.cpp
   src/get_resources.cpp
   src/get_search_paths.cpp
-  src/has_resource.cpp)
+  src/has_resource.cpp
+)
 target_compile_definitions(${PROJECT_NAME} PRIVATE "AMENT_INDEX_CPP_BUILDING_DLL")
 target_include_directories(${PROJECT_NAME} PUBLIC
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>"

ament_index_cpp/include/ament_index_cpp/get_package_prefix.hpp

@@ -0,0 +1,51 @@
+// Copyright 2017 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 AMENT_INDEX_CPP__GET_PACKAGE_PREFIX_HPP_
+#define AMENT_INDEX_CPP__GET_PACKAGE_PREFIX_HPP_
+
+#include <stdexcept>
+#include <string>
+
+#include "ament_index_cpp/visibility_control.h"
+
+namespace ament_index_cpp
+{
+
+/// Thrown when a package is not found.
+class PackageNotFoundError : public std::out_of_range
+{
+public:
+  AMENT_INDEX_CPP_PUBLIC
+  explicit PackageNotFoundError(const std::string & package_name);
+
+  AMENT_INDEX_CPP_PUBLIC
+  virtual ~PackageNotFoundError();
+
+  const std::string package_name;
+};
+
+/// Return the installation prefix of the given package if found.
+/**
+ * \param package_name the name of the package to locate.
+ * \return installation prefix path in which the package was found.
+ * \throws PackageNotFoundError when the given package is not found.
+ */
+AMENT_INDEX_CPP_PUBLIC
+std::string
+get_package_prefix(const std::string & package_name);
+
+}  // namespace ament_index_cpp
+
+#endif  // AMENT_INDEX_CPP__GET_PACKAGE_PREFIX_HPP_

ament_index_cpp/include/ament_index_cpp/get_package_share_directory.hpp

@@ -0,0 +1,37 @@
+// Copyright 2017 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 AMENT_INDEX_CPP__GET_PACKAGE_SHARE_DIRECTORY_HPP_
+#define AMENT_INDEX_CPP__GET_PACKAGE_SHARE_DIRECTORY_HPP_
+
+#include <string>
+
+#include "ament_index_cpp/visibility_control.h"
+
+namespace ament_index_cpp
+{
+
+/// Return the share directory of the given package if found.
+/**
+ * \param package_name the name of the package to locate.
+ * \return share path of the package.
+ * \throws PackageNotFoundError when the given package is not found.
+ */
+AMENT_INDEX_CPP_PUBLIC
+std::string
+get_package_share_directory(const std::string & package_name);
+
+}  // namespace ament_index_cpp
+
+#endif  // AMENT_INDEX_CPP__GET_PACKAGE_SHARE_DIRECTORY_HPP_

ament_index_cpp/include/ament_index_cpp/get_packages_with_prefixes.hpp

@@ -0,0 +1,33 @@
+// Copyright 2017 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 AMENT_INDEX_CPP__GET_PACKAGES_WITH_PREFIXES_HPP_
+#define AMENT_INDEX_CPP__GET_PACKAGES_WITH_PREFIXES_HPP_
+
+#include <map>
+#include <string>
+
+#include "ament_index_cpp/visibility_control.h"
+
+namespace ament_index_cpp
+{
+
+/// Return a map of package names to their installation prefix.
+AMENT_INDEX_CPP_PUBLIC
+std::map<std::string, std::string>
+get_packages_with_prefixes();
+
+}  // namespace ament_index_cpp
+
+#endif  // AMENT_INDEX_CPP__GET_PACKAGES_WITH_PREFIXES_HPP_

ament_index_cpp/src/get_package_prefix.cpp

@@ -0,0 +1,59 @@
+// Copyright 2017 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 "ament_index_cpp/get_package_prefix.hpp"
+
+#include <stdexcept>
+#include <string>
+
+#include "ament_index_cpp/get_resource.hpp"
+#include "ament_index_cpp/get_search_paths.hpp"
+
+namespace ament_index_cpp
+{
+
+static
+std::string
+format_package_not_found_error_message(const std::string & package_name)
+{
+  std::string message = "package '" + package_name + "' not found, searching: [";
+  auto search_paths = get_search_paths();
+  for (const auto & path : search_paths) {
+    message += path + ", ";
+  }
+  if (search_paths.size() > 0) {
+    message = message.substr(0, message.size() - 2);
+  }
+  return message + "]";
+}
+
+PackageNotFoundError::PackageNotFoundError(const std::string & _package_name)
+: std::out_of_range(format_package_not_found_error_message(_package_name)),
+  package_name(_package_name)
+{}
+
+PackageNotFoundError::~PackageNotFoundError() {}
+
+std::string
+get_package_prefix(const std::string & package_name)
+{
+  std::string content;
+  std::string prefix_path;
+  if (!get_resource("packages", package_name, content, &prefix_path)) {
+    throw PackageNotFoundError(package_name);
+  }
+  return prefix_path;
+}
+
+}  // namespace ament_index_cpp

ament_index_cpp/src/get_package_share_directory.cpp

@@ -0,0 +1,30 @@
+// Copyright 2017 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 "ament_index_cpp/get_package_share_directory.hpp"
+
+#include <string>
+
+#include "ament_index_cpp/get_package_prefix.hpp"
+
+namespace ament_index_cpp
+{
+
+std::string
+get_package_share_directory(const std::string & package_name)
+{
+  return get_package_prefix(package_name) + "/share/" + package_name;
+}
+
+}  // namespace ament_index_cpp

ament_index_cpp/src/get_packages_with_prefixes.cpp

@@ -0,0 +1,31 @@
+// Copyright 2017 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 "ament_index_cpp/get_packages_with_prefixes.hpp"
+
+#include <map>
+#include <string>
+
+#include "ament_index_cpp/get_resources.hpp"
+
+namespace ament_index_cpp
+{
+
+std::map<std::string, std::string>
+get_packages_with_prefixes()
+{
+  return get_resources("packages");
+}
+
+}  // namespace ament_index_cpp

ament_index_cpp/test/utest.cpp

@@ -21,6 +21,9 @@
 #include <stdexcept>
 #include <string>
 
+#include "ament_index_cpp/get_package_prefix.hpp"
+#include "ament_index_cpp/get_package_share_directory.hpp"
+#include "ament_index_cpp/get_packages_with_prefixes.hpp"
 #include "ament_index_cpp/get_resource.hpp"
 #include "ament_index_cpp/get_resources.hpp"
 #include "ament_index_cpp/get_search_paths.hpp"
@@ -210,3 +213,56 @@ TEST(AmentIndexCpp, get_resource_underlay_base_path) {
   EXPECT_TRUE(success);
   EXPECT_EQ(base_path, generate_subfolder_path("prefix2"));
 }
+
+TEST(AmentIndexCpp, get_package_prefix) {
+  // Ensure that a known to exist package is found and that a known to not exist package is not.
+  std::list<std::string> subfolders;
+  subfolders.push_back("prefix1");  // only contains foo and bar packages
+  subfolders.push_back("prefix2");  // only contains bar and baz packages
+  set_ament_prefix_path(subfolders);
+  // foo is found in prefix 1
+  EXPECT_EQ(generate_subfolder_path("prefix1"), ament_index_cpp::get_package_prefix("foo"));
+  // bar is in both, but prefix 1 takes precedence
+  EXPECT_EQ(generate_subfolder_path("prefix1"), ament_index_cpp::get_package_prefix("bar"));
+  // baz is found in prefix 2 only
+  EXPECT_EQ(generate_subfolder_path("prefix2"), ament_index_cpp::get_package_prefix("baz"));
+  // exception when package is not found
+  EXPECT_THROW(
+    ament_index_cpp::get_package_prefix("does_not_exist"),
+    ament_index_cpp::PackageNotFoundError);
+  // exception when the package name is empty
+  EXPECT_THROW(
+    ament_index_cpp::get_package_prefix(""),
+    std::runtime_error);
+}
+
+TEST(AmentIndexCpp, get_package_share_directory) {
+  // Ensure that a known to exist package is found and the share directory is correct.
+  std::list<std::string> subfolders;
+  subfolders.push_back("prefix1");  // only contains foo and bar packages
+  subfolders.push_back("prefix2");  // only contains bar and baz packages
+  set_ament_prefix_path(subfolders);
+  // bar is in both, but prefix 1 takes precedence
+  EXPECT_EQ(
+    generate_subfolder_path("prefix1") + "/share/bar",
+    ament_index_cpp::get_package_share_directory("bar"));
+}
+
+TEST(AmentIndexCpp, get_packages_with_prefixes) {
+  // Ensure the list of packages and prefixes matches resource layout.
+  std::list<std::string> subfolders;
+  subfolders.push_back("prefix1");  // only contains foo and bar packages
+  subfolders.push_back("prefix2");  // only contains bar and baz packages
+  set_ament_prefix_path(subfolders);
+
+  std::map<std::string, std::string> packages_with_prefixes =
+    ament_index_cpp::get_packages_with_prefixes();
+  // should be exactly three elements
+  EXPECT_EQ(3UL, packages_with_prefixes.size());
+  // foo is found in prefix 1
+  EXPECT_EQ(generate_subfolder_path("prefix1"), packages_with_prefixes["foo"]);
+  // bar is in both, but prefix 1 takes precedence
+  EXPECT_EQ(generate_subfolder_path("prefix1"), packages_with_prefixes["bar"]);
+  // baz is found in prefix 2 only
+  EXPECT_EQ(generate_subfolder_path("prefix2"), packages_with_prefixes["baz"]);
+}