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fable: Add CustomDeserializer schema type
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5 files changed

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‎fable/CMakeLists.txt

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@@ -50,6 +50,7 @@ if(BuildTests)
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# find src -type f -name "*_test.cpp"
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src/fable/environment_test.cpp
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src/fable/schema/const_test.cpp
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src/fable/schema/custom_test.cpp
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src/fable/schema/enum_test.cpp
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src/fable/schema/factory_test.cpp
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src/fable/schema/factory_advanced_test.cpp

‎fable/include/fable/schema/array.hpp

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@@ -104,7 +104,7 @@ class Array : public Base<Array<T, P>> {
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j["minItems"] = min_items_;
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}
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if (max_items_ != std::numeric_limits<size_t>::max()) {
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j["maxitems"] = max_items_;
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j["maxItems"] = max_items_;
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}
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this->augment_schema(j);
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return j;

‎fable/include/fable/schema/custom.hpp

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@@ -0,0 +1,97 @@
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/*
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* Copyright 2021 Robert Bosch GmbH
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* \file fable/schema/custom.hpp
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* \see fable/schema/custom_test.cpp
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* \see fable/schema/variant.hpp
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*/
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#pragma once
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#ifndef FABLE_SCHEMA_CUSTOM_HPP_
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#define FABLE_SCHEMA_CUSTOM_HPP_
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#include <functional> // for function<>
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#include <fable/schema/interface.hpp> // for Interface, Box
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namespace fable {
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namespace schema {
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/**
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* The CustomDeserializer allows the user to replace the deserialization of a
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* Schema with a custom function.
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*
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* This is especially useful for schema types such as Variants.
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*
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* Note that if you use this, you may have to define to_json yourself.
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*/
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class CustomDeserializer : public schema::Interface {
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public: // Constructors
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CustomDeserializer(Box&& s) : impl_(std::move(s).reset_pointer().get()) {}
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CustomDeserializer(Box&& s, std::function<void(CustomDeserializer*, const Conf&)> f)
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: impl_(std::move(s).reset_pointer().get()), from_conf_fn_(f) {}
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public: // Special
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operator Box() const { return Box{this->clone()}; }
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void set_from_conf(std::function<void(CustomDeserializer*, const Conf&)> f) { from_conf_fn_ = f; }
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CustomDeserializer with_from_conf(std::function<void(CustomDeserializer*, const Conf&)> f) && {
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set_from_conf(f);
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return std::move(*this);
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}
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public: // Overrides
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Interface* clone() const override { return new CustomDeserializer(*this); }
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using Interface::to_json;
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JsonType type() const override { return impl_->type(); }
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std::string type_string() const override { return impl_->type_string(); }
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bool is_required() const override { return impl_->is_required(); }
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const std::string& description() const override { return impl_->description(); }
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void set_description(const std::string& s) override { return impl_->set_description(s); }
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Json usage() const override { return impl_->usage(); }
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Json json_schema() const override { return impl_->json_schema(); };
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void validate(const Conf& c) const override { impl_->validate(c); }
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void to_json(Json& j) const override { impl_->to_json(j); }
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void from_conf(const Conf& c) override {
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if (!from_conf_fn_) {
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throw Error("no deserializer configured");
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}
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from_conf_fn_(this, c);
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}
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void reset_ptr() override {
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impl_->reset_ptr();
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from_conf_fn_ = [](CustomDeserializer*, const Conf&) {
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throw Error("cannot deserialize after reset_ptr is called");
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};
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}
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friend void to_json(Json& j, const CustomDeserializer& b) { b.impl_->to_json(j); }
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private:
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std::shared_ptr<schema::Interface> impl_{nullptr};
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std::function<void(CustomDeserializer*, const Conf&)> from_conf_fn_{};
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};
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} // namespace schema
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} // namespace fable
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#endif // FABLE_SCHEMA_CUSTOM_HPP_

‎fable/include/fable/schema/interface.hpp

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@@ -271,6 +271,11 @@ class Box : public Interface {
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Box(std::shared_ptr<Interface> i) : impl_(std::move(i)) { assert(impl_); } // NOLINT
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public: // Special
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/**
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* Return the underlying Interface.
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*/
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std::shared_ptr<Interface> get() { return impl_; }
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/**
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* Return this type as a pointer to T.
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*
@@ -317,6 +322,11 @@ class Box : public Interface {
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return std::dynamic_pointer_cast<T>(impl_);
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}
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Box reset_pointer() && {
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reset_ptr();
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return std::move(*this);
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}
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public: // Overrides
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using Interface::to_json;
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Interface* clone() const override { return impl_->clone(); }

‎fable/src/fable/schema/custom_test.cpp

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/*
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* Copyright 2021 Robert Bosch GmbH
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* \file fable/schema/custom_test.cpp
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* \see fable/schema/custom.hpp
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*/
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#include <string> // for string
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#include <vector> // for vector<>
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#include <gtest/gtest.h> // for TEST
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#include <fable/confable.hpp> // for Confable
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#include <fable/schema.hpp> // for Schema, Variant, Conf, Json
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#include <fable/schema/custom.hpp> // for CustomDeserializer
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#include <fable/utility/gtest.hpp> // for assert_from_conf
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namespace {
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/**
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* MyCustomStruct models a command that can take either a string which it
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* passes to a shell to run, or an array, which it runs directly.
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*
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* It needs to make use of CustomDeserializer for this to work.
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* We dispense with the error checking that would be required in production
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* code, since this is just a unit test.
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*/
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struct MyCustomStruct : public fable::Confable {
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std::string executable;
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std::vector<std::string> args;
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CONFABLE_SCHEMA(MyCustomStruct) {
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// clang-format off
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using namespace fable;
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using namespace fable::schema; // NOLINT(build/namespaces)
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return Struct{
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{"command", Variant{
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"system command to execute",
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// Variant #1: system command to pass to a shell
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{
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CustomDeserializer(
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make_prototype<std::string>(),
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[this](CustomDeserializer*, const Conf& c) {
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this->executable = "/bin/bash";
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this->args = {"-c", c.get<std::string>()};
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}
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),
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// Variant #2: an array with the first element the command to run
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// and the rest of the items the arguments to the command.
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CustomDeserializer(
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make_prototype<std::vector<std::string>>().min_items(1),
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[this](CustomDeserializer*, const Conf& c) {
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auto args = c.get<std::vector<std::string>>();
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this->executable = args[0];
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for (size_t i = 1; i < args.size(); ++i) {
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this->args.push_back(args[i]);
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}
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}
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),
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},
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}.require()}
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};
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// clang-format on
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}
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void to_json(fable::Json& j) const override {
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j = fable::Json{
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{"executable", executable},
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{"args", args},
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};
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}
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};
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} // anonymous namespace
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TEST(fable_schema_custom, schema) {
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MyCustomStruct tmp;
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fable::assert_schema_eq(tmp, R"({
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"type": "object",
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"properties": {
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"command": {
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"description": "system command to execute",
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"anyOf": [
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{
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"type": "string"
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},
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{
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"type": "array",
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"items": {
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"type": "string"
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},
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"minItems": 1
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}
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]
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}
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},
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"required": ["command"],
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"additionalProperties": false
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})");
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}
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TEST(fable_schema_custom, from_conf) {
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MyCustomStruct tmp;
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fable::assert_from_conf(tmp, R"({
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"command": "echo 'Hello World'"
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})");
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ASSERT_EQ(tmp.executable, "/bin/bash");
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fable::assert_from_conf(tmp, R"({
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"command": ["echo", "Hello World!"]
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})");
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ASSERT_EQ(tmp.executable, "echo");
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fable::assert_invalidate(tmp, R"({
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"command": []
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})");
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ASSERT_EQ(tmp.executable, "echo");
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}
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TEST(fable_schema_custom, to_json) {
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MyCustomStruct tmp;
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tmp.executable = "echo";
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tmp.args = {"Hello World"};
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fable::assert_to_json(tmp, R"({
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"executable": "echo",
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"args": ["Hello World"]
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})");
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}

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