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- /*
- * Copyright 2011-present Facebook, 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 <folly/json_patch.h>
- namespace {
- using folly::StringPiece;
- // JSON patch operation names
- constexpr StringPiece kOperationTest = "test";
- constexpr StringPiece kOperationRemove = "remove";
- constexpr StringPiece kOperationAdd = "add";
- constexpr StringPiece kOperationReplace = "replace";
- constexpr StringPiece kOperationMove = "move";
- constexpr StringPiece kOperationCopy = "copy";
- // field tags in JSON patch
- constexpr StringPiece kOpTag = "op";
- constexpr StringPiece kValueTag = "value";
- constexpr StringPiece kPathTag = "path";
- constexpr StringPiece kFromTag = "from";
- } // namespace
- namespace folly {
- // static
- Expected<json_patch, json_patch::parse_error> json_patch::try_parse(
- dynamic const& obj) noexcept {
- using err_code = parse_error_code;
- json_patch patch;
- if (!obj.isArray()) {
- return makeUnexpected(parse_error{err_code::invalid_shape, &obj});
- }
- for (auto const& elem : obj) {
- if (!elem.isObject()) {
- return makeUnexpected(parse_error{err_code::invalid_shape, &elem});
- }
- auto const* op_ptr = elem.get_ptr(kOpTag);
- if (!op_ptr) {
- return makeUnexpected(parse_error{err_code::missing_op, &elem});
- }
- if (!op_ptr->isString()) {
- return makeUnexpected(parse_error{err_code::malformed_op, &elem});
- }
- auto const op_str = op_ptr->asString();
- patch_operation op;
- // extract 'from' attribute
- {
- auto const* from_ptr = elem.get_ptr(kFromTag);
- if (from_ptr) {
- if (!from_ptr->isString()) {
- return makeUnexpected(parse_error{err_code::invalid_shape, &elem});
- }
- auto json_ptr = json_pointer::try_parse(from_ptr->asString());
- if (!json_ptr.hasValue()) {
- return makeUnexpected(
- parse_error{err_code::malformed_from_attr, &elem});
- }
- op.from = json_ptr.value();
- }
- }
- // extract 'path' attribute
- {
- auto const* path_ptr = elem.get_ptr(kPathTag);
- if (!path_ptr) {
- return makeUnexpected(parse_error{err_code::missing_path_attr, &elem});
- }
- if (!path_ptr->isString()) {
- return makeUnexpected(
- parse_error{err_code::malformed_path_attr, &elem});
- }
- auto const json_ptr = json_pointer::try_parse(path_ptr->asString());
- if (!json_ptr.hasValue()) {
- return makeUnexpected(
- parse_error{err_code::malformed_path_attr, &elem});
- }
- op.path = json_ptr.value();
- }
- // extract 'value' attribute
- {
- auto const* val_ptr = elem.get_ptr(kValueTag);
- if (val_ptr) {
- op.value = *val_ptr;
- }
- }
- // check mandatory attributes - different per operation
- // NOTE: per RFC, the surplus attributes (e.g. 'from' with 'add')
- // should be simply ignored
- using op_code = patch_operation_code;
- if (op_str == kOperationTest) {
- if (!op.value) {
- return makeUnexpected(parse_error{err_code::missing_value_attr, &elem});
- }
- op.op_code = op_code::test;
- } else if (op_str == kOperationRemove) {
- op.op_code = op_code::remove;
- } else if (op_str == kOperationAdd) {
- if (!op.value) {
- return makeUnexpected(parse_error{err_code::missing_value_attr, &elem});
- }
- op.op_code = op_code::add;
- } else if (op_str == kOperationReplace) {
- if (!op.value) {
- return makeUnexpected(parse_error{err_code::missing_value_attr, &elem});
- }
- op.op_code = op_code::replace;
- } else if (op_str == kOperationMove) {
- if (!op.from) {
- return makeUnexpected(parse_error{err_code::missing_from_attr, &elem});
- }
- // is from a proper prefix to path?
- if (op.from->is_prefix_of(op.path)) {
- return makeUnexpected(
- parse_error{err_code::overlapping_pointers, &elem});
- }
- op.op_code = op_code::move;
- } else if (op_str == kOperationCopy) {
- if (!op.from) {
- return makeUnexpected(parse_error{err_code::missing_from_attr, &elem});
- }
- op.op_code = op_code::copy;
- }
- if (op.op_code != op_code::invalid) {
- patch.ops_.emplace_back(std::move(op));
- } else {
- return makeUnexpected(parse_error{err_code::unknown_op, &elem});
- }
- }
- return patch;
- }
- std::vector<json_patch::patch_operation> const& json_patch::ops() const {
- return ops_;
- }
- } // namespace folly
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