cargo: add support for [package]:links

Author: dcbaker

mesonbuild/cargo/cargo.py

@@ -361,7 +361,7 @@ def __parse_lib(self, builder: NodeBuilder) -> None:
                     # We always call the list of dependencies "dependencies",
                     # if there are dependencies we can add them. There could
                     # be an empty dependencies section, so account for that
-                    if self.manifest.get('dependencies') or self.manifest.get('target'):
+                    if self.manifest.get('dependencies') or self.manifest.get('target') or self.manifest['package'].get('links'):
                         fbuilder.keyword('dependencies', builder.id('dependencies'))
 
                     # Always mark everything as build by default false, that way meson will
@@ -586,6 +586,18 @@ def __emit_dependencies(self, builder: NodeBuilder) -> None:
                     if isinstance(dep, str) or not dep.get('optional', False):
                         arbuilder.positional(self.__get_dependency(builder, name))
 
+        # If we need to link with a system library, we'll first try a
+        # dependency
+        #
+        # TODO: if that doesn't work, we need to fall back to adding a C
+        # compiler and running c.find_library()
+        if self.manifest['package'].get('links'):
+            with builder.assignment_builder('link_library') as abuilder:
+                with abuilder.function_builder('dependency') as argbuilder:
+                    argbuilder.positional(self.manifest['package']['links'])
+            with builder.plus_assignment_builder('dependencies') as pabuilder:
+                pabuilder.reference('link_library')
+
         # If it's optional, then we need to check that the feature that
         # it depends on is available, then add it to the dependency array.
         for name, requires in self.features_to_deps.items():
@@ -691,7 +703,7 @@ def parse(self) -> T.Tuple['mparser.CodeBlockNode', 'mparser.CodeBlockNode']:
 
         # Create a list of dependencies which will be added to the library (if
         # there is one).
-        if self.manifest.get('dependencies') or self.manifest.get('target'):
+        if self.manifest.get('dependencies') or self.manifest.get('target') or self.manifest['package'].get('links'):
             self.__emit_dependencies(builder)
         if self.manifest.get('dev-dependencies'):
             self.__emit_dev_dependencies(builder)

mesonbuild/cargo/nodebuilder.py

@@ -215,6 +215,9 @@ def array_builder(self) -> T.Iterator[ArgumentBuilder]:
         array = mparser.ArrayNode(b.finalize(), 0, 0, 0, 0) # _builder.array expects raw arguments
         self._node = self._builder.plus_assign(self.name, array)
 
+    def reference(self, name: str) -> None:
+        self._node = self._builder.plus_assign(self.name, self._builder.id(name))
+
     def finalize(self) -> mparser.PlusAssignmentNode:
         assert self._node is not None, 'You need to build an assignment before finalizing'
         return self._node