commit dfbd181: [Project] Css: Tidy up lambdas

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2021-03-29 14:43:14 +0100
URL: https://github.com/rspamd/rspamd/commit/dfbd181e9cc0dc13eba0d00b0fa77b133ee364f3

[Project] Css: Tidy up lambdas

---
 CMakeLists.txt                     |  2 +-
 src/libserver/css/css_parser.cxx   | 21 +++++++++++++--------
 src/libserver/css/css_parser.hxx   |  3 ++-
 src/libserver/css/css_rule.cxx     |  2 +-
 src/libserver/css/css_rule.hxx     |  2 +-
 src/libserver/css/css_selector.cxx |  2 +-
 src/libserver/css/css_selector.hxx |  4 ++--
 7 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2a42d1886..b53793008 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -119,7 +119,7 @@ INCLUDE_DIRECTORIES("${CMAKE_SOURCE_DIR}/"
 		"${CMAKE_SOURCE_DIR}/contrib/frozen/include"
 		"${CMAKE_SOURCE_DIR}/contrib/fmt/include"
 		"${CMAKE_SOURCE_DIR}/contrib/doctest"
-		"${CMAKE_BINARY_DIR}/contrib/fu2/include"
+		"${CMAKE_SOURCE_DIR}/contrib/fu2/include"
 		"${CMAKE_BINARY_DIR}/src" #Stored in the binary dir
 		"${CMAKE_BINARY_DIR}/src/libcryptobox")
 
diff --git a/src/libserver/css/css_parser.cxx b/src/libserver/css/css_parser.cxx
index d828ffa46..104792693 100644
--- a/src/libserver/css/css_parser.cxx
+++ b/src/libserver/css/css_parser.cxx
@@ -650,13 +650,7 @@ get_selectors_parser_functor(rspamd_mempool_t *pool,
 {
 	css_parser parser(pool);
 
-	/*
-	 * We use shared ptr here to avoid std::function limitation around
-	 * unique_ptr due to copyable of std::function
-	 * Hence, to elongate consumed_blocks lifetime we need to copy them
-	 * inside lambda.
-	 */
-	std::shared_ptr<css_consumed_block> consumed_blocks = parser.consume_css_blocks(st);
+	auto &&consumed_blocks = parser.consume_css_blocks(st);
 	const auto &rules = consumed_blocks->get_blocks_or_empty();
 
 	auto rules_it = rules.begin();
@@ -664,7 +658,18 @@ get_selectors_parser_functor(rspamd_mempool_t *pool,
 	auto cur = children.begin();
 	auto last = children.end();
 
-	return [cur, consumed_blocks, last](void) mutable -> const css_consumed_block & {
+	/*
+	 * We use move only wrapper to state the fact that the cosumed blocks
+	 * are moved into the closure, not copied.
+	 * It prevents us from thinking about copies of the blocks and
+	 * functors.
+	 * Mutable lambda is required to copy iterators inside of the closure,
+	 * as, again, it is C++ where lifetime of the objects must be explicitly
+	 * transferred. On the other hand, we could move all stuff inside and remove
+	 * mutable.
+	 */
+	return [cur, consumed_blocks = std::move(consumed_blocks), last](void) mutable
+		-> const css_consumed_block & {
 		if (cur != last) {
 			const auto &ret = (*cur);
 
diff --git a/src/libserver/css/css_parser.hxx b/src/libserver/css/css_parser.hxx
index 845031618..4b5598fa9 100644
--- a/src/libserver/css/css_parser.hxx
+++ b/src/libserver/css/css_parser.hxx
@@ -24,6 +24,7 @@
 #include <memory>
 #include <string>
 
+#include "function2/function2.hpp"
 #include "css_tokeniser.hxx"
 #include "parse_error.hxx"
 #include "contrib/expected/expected.hpp"
@@ -181,7 +182,7 @@ private:
 
 extern const css_consumed_block css_parser_eof_block;
 
-using blocks_gen_functor = std::function<const css_consumed_block &(void)>;
+using blocks_gen_functor = fu2::unique_function<const css_consumed_block &(void)>;
 
 class css_style_sheet;
 auto parse_css(rspamd_mempool_t *pool, const std::string_view &st) ->
diff --git a/src/libserver/css/css_rule.cxx b/src/libserver/css/css_rule.cxx
index cf04eb689..c301ebdca 100644
--- a/src/libserver/css/css_rule.cxx
+++ b/src/libserver/css/css_rule.cxx
@@ -169,7 +169,7 @@ allowed_property_value(const css_property &prop, const css_consumed_block &parse
 }
 
 auto process_declaration_tokens(rspamd_mempool_t *pool,
-								const blocks_gen_functor &next_block_functor)
+								blocks_gen_functor &&next_block_functor)
 	-> css_declarations_block_ptr
 {
 	css_declarations_block_ptr ret;
diff --git a/src/libserver/css/css_rule.hxx b/src/libserver/css/css_rule.hxx
index c7cbae45d..ec9ccde42 100644
--- a/src/libserver/css/css_rule.hxx
+++ b/src/libserver/css/css_rule.hxx
@@ -105,7 +105,7 @@ private:
 using css_declarations_block_ptr = std::shared_ptr<css_declarations_block>;
 
 auto process_declaration_tokens(rspamd_mempool_t *pool,
-							 const blocks_gen_functor &next_token_functor)
+								blocks_gen_functor &&next_token_functor)
 	-> css_declarations_block_ptr;
 
 }
diff --git a/src/libserver/css/css_selector.cxx b/src/libserver/css/css_selector.cxx
index b198b8553..de7b9afac 100644
--- a/src/libserver/css/css_selector.cxx
+++ b/src/libserver/css/css_selector.cxx
@@ -23,7 +23,7 @@
 namespace rspamd::css {
 
 auto process_selector_tokens(rspamd_mempool_t *pool,
-							 const blocks_gen_functor &next_token_functor)
+							 blocks_gen_functor &&next_token_functor)
 	-> selectors_vec
 {
 	selectors_vec ret;
diff --git a/src/libserver/css/css_selector.hxx b/src/libserver/css/css_selector.hxx
index 5ed4d54b8..7a211c11c 100644
--- a/src/libserver/css/css_selector.hxx
+++ b/src/libserver/css/css_selector.hxx
@@ -23,9 +23,9 @@
 #include <string>
 #include <optional>
 #include <vector>
-#include <functional>
 #include <memory>
 
+#include "function2/function2.hpp"
 #include "parse_error.hxx"
 #include "css_parser.hxx"
 #include "html_tags.h"
@@ -85,7 +85,7 @@ using selectors_vec = std::vector<std::unique_ptr<css_selector>>;
  * Consume selectors token and split them to the list of selectors
  */
 auto process_selector_tokens(rspamd_mempool_t *pool,
-							 const blocks_gen_functor &next_token_functor)
+							 blocks_gen_functor &&next_token_functor)
 	-> selectors_vec;
 
 }