[vcpkg] Add keyword Supports to Feature in CONTROL file and manifest

ports/hunspell/vcpkg.json

@@ -0,0 +1,13 @@
+{
+  "name": "hunspell",
+  "version-string": "1.7.0",
+  "port-version": 3,
+  "description": "The most popular spellchecking library.",
+  "homepage": "https://github.com/hunspell/hunspell",
+  "features": {
+    "tools": {
+      "description": "Build hunspell tools",
+      "supports": "windows"
+    }
+  }
+}

ports/ixwebsocket/CONTROL

@@ -1,5 +1,6 @@
 Source: ixwebsocket
 Version: 9.6.2
+Port-Version: 1
 Build-Depends: zlib
 Homepage: https://github.com/machinezone/IXWebSocket
 Description: Lightweight WebSocket Client and Server + HTTP Client and Server
@@ -20,3 +21,4 @@ Description: SSL support (mbedTLS)
 
 Feature: sectransp
 Description: SSL support (sectransp)
+Supports: osx

ports/libtorrent/CONTROL

@@ -19,10 +19,11 @@ Description: build with libiconv on Windows
 Feature: python
 Build-Depends: boost-python, libtorrent[deprfun]
 Description: build the python bindings in bindings/python directory
+Supports: !windows
 
 Feature: test
 Build-Depends: libtorrent[deprfun]
 Description: build the libtorrent tests
 
 Feature: tools
-Description: build the tools in the tools directory
+Description: build the tools in the tools directory

toolsrc/include/vcpkg/sourceparagraph.h

@@ -42,6 +42,7 @@ namespace vcpkg
         std::string name;
         std::vector<std::string> description;
         std::vector<Dependency> dependencies;
+        PlatformExpression::Expr supports_expression;
 
         Json::Object extra_info;
 

toolsrc/src/vcpkg/sourceparagraph.cpp

@@ -340,6 +340,21 @@ namespace vcpkg
         fpgh->description = Strings::split(parser.required_field(SourceParagraphFields::DESCRIPTION), '\n');
         trim_all(fpgh->description);
 
+        auto supports_expr = parser.optional_field(SourceParagraphFields::SUPPORTS);
+        if (!supports_expr.empty())
+        {
+            auto maybe_expr = PlatformExpression::parse_platform_expression(
+                supports_expr, PlatformExpression::MultipleBinaryOperators::Allow);
+            if (auto expr = maybe_expr.get())
+            {
+                fpgh->supports_expression = std::move(*expr);
+            }
+            else
+            {
+                parser.add_type_error(SourceParagraphFields::SUPPORTS, "a platform expression");
+            }
+        }
+
         auto maybe_dependencies =
             parse_dependencies_list(parser.optional_field(SourceParagraphFields::BUILD_DEPENDS), origin);
         if (maybe_dependencies.has_value())
@@ -517,10 +532,11 @@ namespace vcpkg
         constexpr static StringLiteral NAME = "name";
         constexpr static StringLiteral DESCRIPTION = "description";
         constexpr static StringLiteral DEPENDENCIES = "dependencies";
+        constexpr static StringLiteral SUPPORTS = "supports";
 
         virtual Span<const StringView> valid_fields() const override
         {
-            static const StringView t[] = {DESCRIPTION, DEPENDENCIES};
+            static const StringView t[] = {DESCRIPTION, DEPENDENCIES, SUPPORTS};
             return t;
         }
 
@@ -539,6 +555,7 @@ namespace vcpkg
             r.required_object_field(
                 type_name(), obj, DESCRIPTION, feature->description, Json::ParagraphDeserializer::instance);
             r.optional_object_field(obj, DEPENDENCIES, feature->dependencies, DependencyArrayDeserializer::instance);
+            r.optional_object_field(obj, SUPPORTS, feature->supports_expression, PlatformExprDeserializer{});
 
             return std::move(feature);
         }
@@ -559,6 +576,7 @@ namespace vcpkg
                 FeatureDeserializer::NAME,
                 FeatureDeserializer::DESCRIPTION,
                 FeatureDeserializer::DEPENDENCIES,
+                FeatureDeserializer::SUPPORTS,
             };
             return t;
         }
@@ -1204,6 +1222,8 @@ namespace vcpkg
                 }
 
                 serialize_paragraph(feature_obj, FeatureDeserializer::DESCRIPTION, feature->description, true);
+                serialize_optional_string(
+                    feature_obj, FeatureDeserializer::SUPPORTS, to_string(feature->supports_expression));
 
                 if (!feature->dependencies.empty() || debug)
                 {