Merge #379: type: Accept any comparator, hash, and allocator in container fields

9a42d00 type: Accept any comparator, hash, and allocator in container fields (Ryan Ofsky)

Pull request description:

  **Problem:** `std::vector`, `std::set`, `std::map` and `std::unordered_set` fields and parameters only work when they use the default comparator, hash and allocator types. Anything else, like Bitcoin Core's `GCSFilter::ElementSet` (`std::unordered_set<Element, ByteVectorHash>`), fails to compile with "no matching function for call to CustomBuildField". Bitcoin Core currently works around this by copying the `std::unordered_set` read and build functions into its own code (bitcoin/bitcoin#29409).

  **Solution:** Make the container overloads in `type-vector.h`, `type-set.h`, `type-map.h` and `type-unordered-set.h` templates over the containers' comparator, hash and allocator types. Small change to the four headers, plus a `FooStruct` round-trip test with a descending `std::set` and `std::map`, an `std::unordered_set` with a custom hash, and a `std::pmr::vector`.

ACKs for top commit:
  xyzconstant:
    ACK 9a42d00

Tree-SHA512: 53f791f3aa0d70a29d89be1335fb68d088c6f59d90cd6f2c18a2a01eeab968bb77615a6a81699b0202bedad49bb427acdfbe743cc75b6a4ed517db5eae2c9a7a

Author: ryanofsky

include/mp/type-map.h

@@ -12,8 +12,8 @@
 #include <map>
 
 namespace mp {
-template <typename KeyLocalType, typename ValueLocalType, typename Value, typename Output>
-void CustomBuildField(TypeList<std::map<KeyLocalType, ValueLocalType>>,
+template <typename KeyLocalType, typename ValueLocalType, typename Compare, typename Allocator, typename Value, typename Output>
+void CustomBuildField(TypeList<std::map<KeyLocalType, ValueLocalType, Compare, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Value&& value,
@@ -51,8 +51,8 @@ auto EmplacePiecewiseSafe(
     }
 }
 
-template <typename KeyLocalType, typename ValueLocalType, typename Input, typename ReadDest>
-decltype(auto) CustomReadField(TypeList<std::map<KeyLocalType, ValueLocalType>>,
+template <typename KeyLocalType, typename ValueLocalType, typename Compare, typename Allocator, typename Input, typename ReadDest>
+decltype(auto) CustomReadField(TypeList<std::map<KeyLocalType, ValueLocalType, Compare, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Input&& input,

include/mp/type-set.h

@@ -9,8 +9,8 @@
 #include <mp/util.h>
 
 namespace mp {
-template <typename LocalType, typename Value, typename Output>
-void CustomBuildField(TypeList<std::set<LocalType>>,
+template <typename LocalType, typename Compare, typename Allocator, typename Value, typename Output>
+void CustomBuildField(TypeList<std::set<LocalType, Compare, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Value&& value,
@@ -19,8 +19,8 @@ void CustomBuildField(TypeList<std::set<LocalType>>,
     BuildList(TypeList<LocalType>(), invoke_context, output, value);
 }
 
-template <typename LocalType, typename Input, typename ReadDest>
-decltype(auto) CustomReadField(TypeList<std::set<LocalType>>,
+template <typename LocalType, typename Compare, typename Allocator, typename Input, typename ReadDest>
+decltype(auto) CustomReadField(TypeList<std::set<LocalType, Compare, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Input&& input,

include/mp/type-unordered-set.h

@@ -10,8 +10,8 @@
 #include <unordered_set>
 
 namespace mp {
-template <typename LocalType, typename Value, typename Output>
-void CustomBuildField(TypeList<std::unordered_set<LocalType>>,
+template <typename LocalType, typename Hash, typename KeyEqual, typename Allocator, typename Value, typename Output>
+void CustomBuildField(TypeList<std::unordered_set<LocalType, Hash, KeyEqual, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Value&& value,
@@ -20,8 +20,8 @@ void CustomBuildField(TypeList<std::unordered_set<LocalType>>,
     BuildList(TypeList<LocalType>(), invoke_context, output, value);
 }
 
-template <typename LocalType, typename Input, typename ReadDest>
-decltype(auto) CustomReadField(TypeList<std::unordered_set<LocalType>>,
+template <typename LocalType, typename Hash, typename KeyEqual, typename Allocator, typename Input, typename ReadDest>
+decltype(auto) CustomReadField(TypeList<std::unordered_set<LocalType, Hash, KeyEqual, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Input&& input,

include/mp/type-vector.h

@@ -9,8 +9,8 @@
 #include <mp/util.h>
 
 namespace mp {
-template <typename LocalType, typename Value, typename Output>
-void CustomBuildField(TypeList<std::vector<LocalType>>,
+template <typename LocalType, typename Allocator, typename Value, typename Output>
+void CustomBuildField(TypeList<std::vector<LocalType, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Value&& value,
@@ -24,8 +24,8 @@ inline static bool BuildPrimitive(InvokeContext&, std::vector<bool>::const_refer
     return value;
 }
 
-template <typename LocalType, typename Input, typename ReadDest>
-decltype(auto) CustomReadField(TypeList<std::vector<LocalType>>,
+template <typename LocalType, typename Allocator, typename Input, typename ReadDest>
+decltype(auto) CustomReadField(TypeList<std::vector<LocalType, Allocator>>,
     Priority<1>,
     InvokeContext& invoke_context,
     Input&& input,

test/mp/test/foo.capnp

@@ -72,6 +72,10 @@ struct FooStruct $Proxy.wrap("mp::test::FooStruct") {
     hasOptionalInt @4 :Bool;
     unorderedSetInt @5 :List(Int32) $Proxy.name("unordered_set_int");
     mapStringInt @6 :List(StringIntPair) $Proxy.name("map_string_int");
+    setIntDesc @7 :List(Int32) $Proxy.name("set_int_desc");
+    pmrVectorInt @8 :List(Int32) $Proxy.name("pmr_vector_int");
+    unorderedSetStringHash @9 :List(Text) $Proxy.name("unordered_set_string_hash");
+    mapStringIntDesc @10 :List(StringIntPair) $Proxy.name("map_string_int_desc");
 }
 
 struct FooCustom $Proxy.wrap("mp::test::FooCustom") {

test/mp/test/foo.h

@@ -6,9 +6,11 @@
 #define MP_TEST_FOO_H
 
 #include <cassert>
+#include <cstddef>
 #include <functional>
 #include <map>
 #include <memory>
+#include <memory_resource>
 #include <optional>
 #include <string>
 #include <set>
@@ -18,6 +20,12 @@
 namespace mp {
 namespace test {
 
+//! Hash function used to test std::unordered_set with a custom hash.
+struct FooHash
+{
+    size_t operator()(const std::string& str) const { return str.size(); }
+};
+
 struct FooStruct
 {
     std::string name;
@@ -26,6 +34,11 @@ struct FooStruct
     std::optional<int> optional_int;
     std::unordered_set<int> unordered_set_int;
     std::map<std::string, int> map_string_int;
+    // Containers with non-default comparator, allocator, and hash types.
+    std::set<int, std::greater<>> set_int_desc;
+    std::pmr::vector<int> pmr_vector_int;
+    std::unordered_set<std::string, FooHash> unordered_set_string_hash;
+    std::map<std::string, int, std::greater<>> map_string_int_desc;
 };
 
 enum class FooEnum : uint8_t { ONE = 1, TWO = 2, };

test/mp/test/test.cpp

@@ -174,6 +174,10 @@ KJ_TEST("Call FooInterface methods")
     in.optional_int = 3;
     in.map_string_int.emplace("a", 1);
     in.map_string_int.emplace("b", 2);
+    in.set_int_desc = {1, 2, 3};
+    in.pmr_vector_int = {3, 1, 2};
+    in.unordered_set_string_hash = {"a", "bb"};
+    in.map_string_int_desc = {{"a", 1}, {"b", 2}};
     FooStruct out = foo->pass(in);
     KJ_EXPECT(in.name == out.name);
     KJ_EXPECT(in.set_int.size() == out.set_int.size());
@@ -194,6 +198,10 @@ KJ_TEST("Call FooInterface methods")
         KJ_EXPECT(init->first == outit->first);
         KJ_EXPECT(init->second == outit->second);
     }
+    KJ_EXPECT(in.set_int_desc == out.set_int_desc);
+    KJ_EXPECT(in.pmr_vector_int == out.pmr_vector_int);
+    KJ_EXPECT(in.unordered_set_string_hash == out.unordered_set_string_hash);
+    KJ_EXPECT(in.map_string_int_desc == out.map_string_int_desc);
 
     // Additional checks for std::optional member
     KJ_EXPECT(foo->pass(in).optional_int == 3);