YAML parameter parser (ros2#235)

* Implement a basic YAML based parameter parser for ros2 nodes

* Add README file

* Fix the issues after moving from rcutils_yaml_param_parser to rcl_yaml_param_parser

  - rename folders from rcutils_yaml_param_parser to rcl_yaml_param_parser
  - rename project, header guards and include statements from rcutils_yaml_param_parser to rcl_yaml_param_parser
  - move type declaration in separat file and namespace new structures
  - Fix the code review comments from Mikael

* Few minor changes

   - Changed "params" string to "ros__parameters"
   - Add -Wall, -Wextra and -Wpedantic falgs
   - Fix the compile warning with the new flags

* Fix the changes made in the design of C structure

  - Remove the node_namespaces entry in rcl_params_t
  - Change the type of num_nodes and num_params to size_t

* depend on libyaml_vendor (ros2#236)

* Fix cmake setting standard(C and C++) and add byte_array in C struct

*   Remove C11 so that it defaults to C99

* [rcl_yaml_param_parser] fix export symbols (ros2#237)

* add visibility macros

* remove unused macro

* Support for multi level node and parameter name spaces

* Additional fixes and cleanups

  - Support for string namespace seperator
  - Provide parameter structure init function API
  - name cleanups

* off by 1

* Call yaml_parser_delete()

* fclose(yaml_file)

* free() allocated paths

* Call yaml_event_delete()

* completely deallcoate string array

* Few cleanup changes

  - Add install command into CMakelists.txt
  - Replace one of the zero_allocate with reallocate
  - Pass allocator state
  - Fix int32_t -> rcl_ret_t return value

* Don't include unistd.h

* Use size_t for array indices

* Just pass the allocator in the init function

rcl_yaml_param_parser/CMakeLists.txt

@@ -0,0 +1,62 @@
+cmake_minimum_required(VERSION 3.5)
+
+project(rcl_yaml_param_parser)
+
+find_package(ament_cmake_ros REQUIRED)
+find_package(rcutils REQUIRED)
+find_package(rcl REQUIRED)
+find_package(libyaml_vendor REQUIRED)
+find_package(yaml REQUIRED)
+
+# Default to C++14
+if(NOT CMAKE_CXX_STANDARD)
+  set(CMAKE_CXX_STANDARD 14)
+endif()
+
+if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang")
+  add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
+
+include_directories(include ${yaml_INCLUDE_DIRS} ${rcutils_INCLUDE_DIRS} ${rcl_INCLUDE_DIRS})
+
+set(rcl_yaml_parser_sources
+  src/parser.c
+)
+
+add_library(
+  ${PROJECT_NAME}
+  ${rcl_yaml_parser_sources})
+ament_target_dependencies(${PROJECT_NAME} "yaml" "rcutils" "rcl")
+
+# 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 "RCL_YAML_PARAM_PARSER_BUILDING_DLL")
+
+install(TARGETS ${PROJECT_NAME}
+  ARCHIVE DESTINATION lib
+  LIBRARY DESTINATION lib
+  RUNTIME DESTINATION bin)
+
+if(BUILD_TESTING)
+  find_package(ament_cmake_gtest REQUIRED)
+  find_package(ament_lint_auto REQUIRED)
+  ament_lint_auto_find_test_dependencies()
+
+  # Gtests
+  ament_add_gtest(test_parse_yaml
+    test/test_parse_yaml.cpp
+  )
+  if(TARGET test_parse_yaml)
+    target_link_libraries(test_parse_yaml ${PROJECT_NAME})
+  endif()
+
+endif()
+
+ament_export_dependencies(ament_cmake)
+ament_export_include_directories(include)
+install(
+  DIRECTORY include/
+  DESTINATION include
+)
+ament_export_libraries(${PROJECT_NAME})
+ament_package()

rcl_yaml_param_parser/README.md

@@ -0,0 +1,27 @@
+**ROS2 rcl YAML paramter parser**
+
+Parse a YAML parameter file and populate the C data structure
+
+The data structure params_st will then be used during node initialization
+
+YAML parameter file should follow the yaml syntax shown below
+
+NOTE: It only supports canonical int and float types
+
+```
+<node_namespace_string>:  # optional
+  <node1_name>:
+    params:
+      <field_name>: <field_value>
+      <parameter_namespace_string>:   # optional
+        <field1_name>: <field1_value>
+        <field2_name>: <field2_value>
+  <node2_name>:
+    params:
+      <field_name>: <field_value>
+      <parameter_namespace_string>:   # optional
+        <field1_name>: <field1_value>
+        <field2_name>: <field2_value>
+```
+
+This package depends on C libyaml

rcl_yaml_param_parser/include/rcl_yaml_param_parser/parser.h

@@ -0,0 +1,60 @@
+// Copyright 2018 Apex.AI, 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 RCL_YAML_PARAM_PARSER__PARSER_H_
+#define RCL_YAML_PARAM_PARSER__PARSER_H_
+
+#include <stdlib.h>
+
+#include "rcl_yaml_param_parser/types.h"
+#include "rcl_yaml_param_parser/visibility_control.h"
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+/// \brief Init param structure
+/// \param[in] allocator memory allocator to be used
+/// \return a pointer to param structure on success or NULL on failure
+RCL_YAML_PARAM_PARSER_PUBLIC
+rcl_params_t * rcl_yaml_node_struct_init(
+  const rcutils_allocator_t allocator);
+
+/// \brief Free param structure
+/// \param[in] params_st points to the populated paramter struct
+RCL_YAML_PARAM_PARSER_PUBLIC
+void rcl_yaml_node_struct_fini(
+  rcl_params_t * params_st);
+
+/// \brief Parse the YAML file, initialize and populate params_st
+/// \param[in] file_path is the path to the YAML file
+/// \param[in/out] params_st points to the populated paramter struct
+/// \return true on success and false on failure
+RCL_YAML_PARAM_PARSER_PUBLIC
+bool rcl_parse_yaml_file(
+  const char * file_path,
+  rcl_params_t * params_st);
+
+/// \brief Print the parameter structure to stdout
+/// \param[in] params_st points to the populated parameter struct
+RCL_YAML_PARAM_PARSER_PUBLIC
+void rcl_yaml_node_struct_print(
+  const rcl_params_t * const params_st);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // RCL_YAML_PARAM_PARSER__PARSER_H_

rcl_yaml_param_parser/include/rcl_yaml_param_parser/types.h

@@ -0,0 +1,87 @@
+// Copyright 2018 Apex.AI, 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 RCL_YAML_PARAM_PARSER__TYPES_H_
+#define RCL_YAML_PARAM_PARSER__TYPES_H_
+
+#include "rcl/allocator.h"
+#include "rcutils/types/string_array.h"
+
+/// \typedef rcl_bool_array_t
+/// \brief Array of bool values
+typedef struct rcl_bool_array_s
+{
+  bool * values;
+  size_t size;
+} rcl_bool_array_t;
+
+/// \typedef rcl_int64_array_t
+/// \brief Array of int64_t values
+typedef struct rcl_int64_array_s
+{
+  int64_t * values;
+  size_t size;
+} rcl_int64_array_t;
+
+/// \typedef rcl_double_array_t
+/// \brief Array of double values
+typedef struct rcl_double_array_s
+{
+  double * values;
+  size_t size;
+} rcl_double_array_t;
+
+/// \typedef rcl_byte_array_t
+/// \brief Array of byte values
+typedef struct rcl_byte_array_s
+{
+  uint8_t * values;
+  size_t size;
+} rcl_byte_array_t;
+
+/// \typedef rcl_variant_t
+/// \brief variant_t stores the value of a parameter
+/// Only one pointer in this struct will store the value
+typedef struct rcl_variant_s
+{
+  bool * bool_value;  ///< If bool, gets stored here
+  int64_t * integer_value;  ///< If integer, gets stored here
+  double * double_value;  ///< If double, gets stored here
+  char * string_value;  ///< If string, gets stored here
+  rcl_byte_array_t * byte_array_value;  ///< If array of bytes
+  rcl_bool_array_t * bool_array_value;  ///< If array of bool's
+  rcl_int64_array_t * integer_array_value;  ///< If array of integers
+  rcl_double_array_t * double_array_value;  ///< If array of doubles
+  rcutils_string_array_t * string_array_value;  ///< If array of strings
+} rcl_variant_t;
+
+/// \typedef rcl_node_params_t
+/// \brief node_params_t stores all the parameters(key:value) of a single node
+typedef struct rcl_node_params_s
+{
+  char ** parameter_names;  ///< Array of parameter names (keys)
+  rcl_variant_t * parameter_values;  ///< Array of coressponding parameter values
+  size_t num_params;  ///< Number of parameters in the node
+} rcl_node_params_t;
+
+/// \typedef rcl_params_t
+/// \brief params_t stores all the parameters of all nodes of a process
+typedef struct rcl_params_s
+{
+  char ** node_names;  ///< List of names of the node
+  rcl_node_params_t * params;  ///<  Array of parameters
+  size_t num_nodes;       ///< Number of nodes
+  rcl_allocator_t allocator;  ///< Allocator used
+} rcl_params_t;
+
+#endif  // RCL_YAML_PARAM_PARSER__TYPES_H_

rcl_yaml_param_parser/include/rcl_yaml_param_parser/visibility_control.h

@@ -0,0 +1,58 @@
+// Copyright 2015 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 RCL_YAML_PARAM_PARSER__VISIBILITY_CONTROL_H_
+#define RCL_YAML_PARAM_PARSER__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 RCL_YAML_PARAM_PARSER_EXPORT __attribute__ ((dllexport))
+    #define RCL_YAML_PARAM_PARSER_IMPORT __attribute__ ((dllimport))
+  #else
+    #define RCL_YAML_PARAM_PARSER_EXPORT __declspec(dllexport)
+    #define RCL_YAML_PARAM_PARSER_IMPORT __declspec(dllimport)
+  #endif
+  #ifdef RCL_YAML_PARAM_PARSER_BUILDING_DLL
+    #define RCL_YAML_PARAM_PARSER_PUBLIC RCL_YAML_PARAM_PARSER_EXPORT
+  #else
+    #define RCL_YAML_PARAM_PARSER_PUBLIC RCL_YAML_PARAM_PARSER_IMPORT
+  #endif
+  #define RCL_YAML_PARAM_PARSER_PUBLIC_TYPE RCL_YAML_PARAM_PARSER_PUBLIC
+  #define RCL_YAML_PARAM_PARSER_LOCAL
+#else
+  #define RCL_YAML_PARAM_PARSER_EXPORT __attribute__ ((visibility("default")))
+  #define RCL_YAML_PARAM_PARSER_IMPORT
+  #if __GNUC__ >= 4
+    #define RCL_YAML_PARAM_PARSER_PUBLIC __attribute__ ((visibility("default")))
+    #define RCL_YAML_PARAM_PARSER_LOCAL  __attribute__ ((visibility("hidden")))
+  #else
+    #define RCL_YAML_PARAM_PARSER_PUBLIC
+    #define RCL_YAML_PARAM_PARSER_LOCAL
+  #endif
+  #define RCL_YAML_PARAM_PARSER_PUBLIC_TYPE
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // RCL_YAML_PARAM_PARSER__VISIBILITY_CONTROL_H_

rcl_yaml_param_parser/package.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0"?>
+<?xml-model href="http://download.ros.org/schema/package_format2.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
+<package format="2">
+  <name>rcl_yaml_param_parser</name>
+  <version>0.1.0</version>
+  <description>Package containing various utility types and functions for C</description>
+  <maintainer email="anup.pemmaiah@apex.ai">Anup Pemmaiah</maintainer>
+  <license>Apache License 2.0</license>
+
+  <buildtool_depend>ament_cmake_ros</buildtool_depend>
+
+  <depend>libyaml_vendor</depend>
+  <depend>yaml</depend>
+  <build_depend>rcutils</build_depend>
+  <build_depend>rcl</build_depend>
+
+  <test_depend>ament_cmake_gtest</test_depend>
+  <test_depend>ament_lint_common</test_depend>
+  <test_depend>ament_lint_auto</test_depend>
+  <test_depend>launch_testing</test_depend>
+
+  <export>
+    <build_type>ament_cmake</build_type>
+  </export>
+</package>