From 6bbc603b22b9a91b748fcdf22cc82650e44d1a91 Mon Sep 17 00:00:00 2001 From: Nicolas Le Scouarnec Date: Sat, 4 Nov 2023 09:22:05 +0100 Subject: [PATCH] Adding support for handling YAML Merge Key (#41) Support for YAML Merge keys ( <<: [*dict1, *dict2] ) is added. The merge key is a specific scalar with value << (and tag !!merge) that implies that during node construction, the map (or sequence of maps) are merged into the current map. The priority rules are that each key from maps within the value associated with << are added iff the key is not yet present in the current map (and first map gets higher priority). Test cases have been added accordingly. --- include/yaml-cpp/exceptions.h | 2 ++ src/nodebuilder.cpp | 48 +++++++++++++++++++++++++++-- src/nodebuilder.h | 1 + test/integration/load_node_test.cpp | 37 ++++++++++++++++++++++ 4 files changed, 85 insertions(+), 3 deletions(-) diff --git a/include/yaml-cpp/exceptions.h b/include/yaml-cpp/exceptions.h index f6b2602..9c8da4c 100644 --- a/include/yaml-cpp/exceptions.h +++ b/include/yaml-cpp/exceptions.h @@ -87,6 +87,8 @@ const char* const INVALID_ANCHOR = "invalid anchor"; const char* const INVALID_ALIAS = "invalid alias"; const char* const INVALID_TAG = "invalid tag"; const char* const BAD_FILE = "bad file"; +const char* const MERGE_KEY_NEEDS_SINGLE_OR_SEQUENCE_OF_MAPS = + "merge key needs either single map or sequence of maps"; template inline const std::string KEY_NOT_FOUND_WITH_KEY( diff --git a/src/nodebuilder.cpp b/src/nodebuilder.cpp index bbaefac..dcddd05 100644 --- a/src/nodebuilder.cpp +++ b/src/nodebuilder.cpp @@ -15,6 +15,7 @@ NodeBuilder::NodeBuilder() m_stack{}, m_anchors{}, m_keys{}, + m_mergeDicts{}, m_mapDepth(0) { m_anchors.push_back(nullptr); // since the anchors start at 1 } @@ -71,8 +72,24 @@ void NodeBuilder::OnMapStart(const Mark& mark, const std::string& tag, m_mapDepth++; } +void MergeMapCollection(detail::node& map_to, detail::node& map_from, + detail::shared_memory_holder& pMemory) { + const detail::node& const_map_to = map_to; + for (auto j = map_from.begin(); j != map_from.end(); j++) { + detail::node* s = const_map_to.get(*j->first, pMemory); + if (s == nullptr) { + map_to.insert(*j->first, *j->second, pMemory); + } + } +} + void NodeBuilder::OnMapEnd() { assert(m_mapDepth > 0); + detail::node& collection = *m_stack.back(); + for (detail::node* n : m_mergeDicts) { + MergeMapCollection(collection, *n, m_pMemory); + } + m_mergeDicts.clear(); m_mapDepth--; Pop(); } @@ -107,15 +124,40 @@ void NodeBuilder::Pop() { m_stack.pop_back(); detail::node& collection = *m_stack.back(); - if (collection.type() == NodeType::Sequence) { collection.push_back(node, m_pMemory); } else if (collection.type() == NodeType::Map) { assert(!m_keys.empty()); PushedKey& key = m_keys.back(); if (key.second) { - collection.insert(*key.first, node, m_pMemory); - m_keys.pop_back(); + detail::node& nk = *key.first; + if (nk.type() == NodeType::Scalar && + ((nk.tag() == "tag:yaml.org,2002:merge" && nk.scalar() == "<<") || + (nk.tag() == "?" && nk.scalar() == "<<"))) { + if (node.type() == NodeType::Map) { + m_mergeDicts.emplace_back(&node); + m_keys.pop_back(); + } else if (node.type() == NodeType::Sequence) { + for (auto i = node.begin(); i != node.end(); i++) { + auto v = *i; + if ((*v).type() == NodeType::Map) { + m_mergeDicts.emplace_back(&(*v)); + } else { + throw ParserException( + node.mark(), + ErrorMsg::MERGE_KEY_NEEDS_SINGLE_OR_SEQUENCE_OF_MAPS); + } + } + m_keys.pop_back(); + } else { + throw ParserException( + node.mark(), + ErrorMsg::MERGE_KEY_NEEDS_SINGLE_OR_SEQUENCE_OF_MAPS); + } + } else { + collection.insert(*key.first, node, m_pMemory); + m_keys.pop_back(); + } } else { key.second = true; } diff --git a/src/nodebuilder.h b/src/nodebuilder.h index c580d40..c8f2804 100644 --- a/src/nodebuilder.h +++ b/src/nodebuilder.h @@ -67,6 +67,7 @@ class NodeBuilder : public EventHandler { using PushedKey = std::pair; std::vector m_keys; + Nodes m_mergeDicts; std::size_t m_mapDepth; }; } // namespace YAML diff --git a/test/integration/load_node_test.cpp b/test/integration/load_node_test.cpp index 9d0c790..b670b64 100644 --- a/test/integration/load_node_test.cpp +++ b/test/integration/load_node_test.cpp @@ -173,6 +173,43 @@ TEST(LoadNodeTest, CloneAlias) { EXPECT_EQ(clone[0], clone); } +TEST(LoadNodeTest, MergeKeyA) { + Node node = Load( + "{x: &foo {a : 1,b : 1,c : 1}, y: &bar {d: 2, e : 2, f : 2, a : 2}, z: " + "&stuff { << : *foo, b : 3} }"); + EXPECT_EQ(NodeType::Map, node["z"].Type()); + EXPECT_FALSE(node["z"]["<<"]); + EXPECT_EQ(1, node["z"]["a"].as()); + EXPECT_EQ(3, node["z"]["b"].as()); + EXPECT_EQ(1, node["z"]["c"].as()); +} + +TEST(LoadNodeTest, MergeKeyB) { + Node node = Load( + "{x: &foo {a : 1,b : 1,c : 1}, y: &bar {d: 2, e : 2, f : 2, a : 2}, z: " + "&stuff { << : *foo, b : 3}, w: { << : [*stuff, *bar], c: 4 }, v: { '<<' " + ": *foo } , u : {!!merge << : *bar} }"); + EXPECT_EQ(NodeType::Map, node["z"].Type()); + EXPECT_EQ(NodeType::Map, node["w"].Type()); + EXPECT_FALSE(node["z"]["<<"]); + EXPECT_EQ(1, node["z"]["a"].as()); + EXPECT_EQ(3, node["z"]["b"].as()); + EXPECT_EQ(1, node["z"]["c"].as()); + + EXPECT_EQ(1, node["w"]["a"].as()); + EXPECT_EQ(3, node["w"]["b"].as()); + EXPECT_EQ(4, node["w"]["c"].as()); + EXPECT_EQ(2, node["w"]["d"].as()); + EXPECT_EQ(2, node["w"]["e"].as()); + EXPECT_EQ(2, node["w"]["f"].as()); + + EXPECT_TRUE(node["v"]["<<"]); + EXPECT_EQ(1, node["v"]["<<"]["a"].as()); + + EXPECT_FALSE(node["u"]["<<"]); + EXPECT_EQ(2, node["u"]["d"].as()); +} + TEST(LoadNodeTest, ForceInsertIntoMap) { Node node; node["a"] = "b";