Adds experimental csharp support

Author: pcj

bzl/classes.bzl

@@ -1,5 +1,6 @@
 load("//bzl:base/class.bzl", BASE = "CLASS")
 load("//bzl:cpp/class.bzl", CPP = "CLASS")
+load("//bzl:csharp/class.bzl", CSHARP = "CLASS")
 load("//bzl:go/class.bzl", GO = "CLASS")
 load("//bzl:python/class.bzl", PYTHON = "CLASS")
 load("//bzl:ruby/class.bzl", RUBY = "CLASS")
@@ -10,6 +11,7 @@ load("//bzl:grpc_gateway/class.bzl", GATEWAY = "CLASS")
 CLASSES = {
     BASE.name: BASE,
     CPP.name: CPP,
+    CSHARP.name: CSHARP,
     GATEWAY.name: GATEWAY,
     JAVA.name: JAVA,
     JAVANANO.name: JAVANANO,

bzl/csharp/README.md

@@ -5,5 +5,5 @@
 | ---  | --- |
 | `csharp_proto_library` | Generates and compiles protobuf source files. |
 
-Support for C# is limited to the proto_compile rule.  Semantics are
-identical to `cc_proto_compile`.
+**Experimental*.  Support for C# is limited to the proto_compile rule.
+Semantics are identical to `cc_proto_compile`.

bzl/csharp/class.bzl

@@ -0,0 +1,18 @@
+load("//bzl:base/class.bzl", BASE = "CLASS")
+
+def csharp_library(**kwargs):
+    """Dummy implementation."""
+    pass
+
+
+CLASS = struct(
+    parent = BASE,
+    name = "csharp",
+
+    protobuf = struct(
+        file_extensions = ["_pb.rb"],
+        compile_deps = [],
+    ),
+
+    library = csharp_library,
+)

bzl/csharp/rules.bzl

@@ -0,0 +1,13 @@
+load("//bzl:base/rules.bzl", "proto_library")
+load("//bzl:protoc.bzl", "implement")
+load("//bzl:csharp/class.bzl", CSHARP = "CLASS")
+
+SPEC = [CSHARP]
+
+csharp_proto_compile = implement(SPEC)
+
+def csharp_proto_library(name, **kwargs):
+  proto_library(name,
+                proto_compile = csharp_proto_compile,
+                spec = SPEC,
+                **kwargs)

bzl/rules.bzl

@@ -8,6 +8,7 @@ def protobuf_repositories(
     overrides = {},
     verbose = 0,
     with_cpp=False,
+    with_csharp=False,
     with_go=False,
     with_java=False,
     with_javanano=False,
@@ -48,6 +49,8 @@ def protobuf_repositories(
 
   if with_cpp:
     classes += ["cpp"]
+  if with_csharp:
+    classes += ["csharp"]
   if with_python:
     classes += ["python"]
   if with_go:

examples/proto/BUILD

@@ -3,6 +3,7 @@ package(default_visibility = ["//visibility:public"])
 load("//bzl:cpp/rules.bzl", "cc_proto_library")
 load("//bzl:go/rules.bzl", "go_proto_library")
 load("//bzl:ruby/rules.bzl", "ruby_proto_library")
+load("//bzl:csharp/rules.bzl", "csharp_proto_library")
 
 filegroup(
     name = "protos",
@@ -23,10 +24,21 @@ cc_proto_library(
     verbose = 1,
 )
 
-# This must be called with ':rb.pb' due to lack of implementing library rule for the moment.
+# Work-in-progress.  This must be called with ':rb.pb' due to lack of
+# implementing library rule for the moment.
 #
 ruby_proto_library(
     name = "rb",
     protos = [":protos"],
     verbose = 1,
 )
+
+# Work-in-progress. This must be called with ':cs.pb' due to lack of
+# implementing library rule for the moment.  It also gets placed in
+# the outdir directly rather than the package dir.
+#
+# csharp_proto_library(
+#     name = "csharp",
+#     protos = [":protos"],
+#     verbose = 1,
+# )