chore: do TODO so all wkt are available

Author: alexeagle

protoc/private/prebuilt_protoc_toolchain.bzl

@@ -5,6 +5,23 @@ It exposes bin/protoc as a proto_toolchain.
 
 load(":versions.bzl", "PROTOC_PLATFORMS", "PROTOC_VERSIONS")
 
+# TODO: we should read this dynamically by `ls *.proto` and then search for "import" statements
+# inside the files. Currently this assumes the wkt srcs/deps are fixed over time.
+GOOGLE_PROTOBUF_DEP_EDGES = {
+    "any": [],
+    "api": ["source_context", "type"],
+    "compiler/plugin": ["descriptor"],
+    "descriptor": [],
+    "duration": [],
+    "empty": [],
+    "field_mask": [],
+    "source_context": [],
+    "struct": [],
+    "timestamp": [],
+    "type": ["any", "source_context"],
+    "wrappers": [],
+}
+
 def _prebuilt_protoc_repo_impl(rctx):
     release_version = rctx.attr.version
 
@@ -21,7 +38,7 @@ def _prebuilt_protoc_repo_impl(rctx):
         url = url,
         integrity = PROTOC_VERSIONS[release_version][filename],
     )
-    rctx.file("BUILD.bazel", """\
+    build_content = """\
 # Generated by @rules_proto//proto/toolchains:prebuilt_protoc_toolchain.bzl
 load("@rules_proto//proto/private/rules:proto_toolchain_rule.bzl", "proto_toolchain")
 
@@ -32,17 +49,20 @@ proto_toolchain(
     proto_compiler = "{protoc_label}",
     visibility = ["//visibility:public"],
 )
+""".format(
+        protoc_label = ":bin/protoc.exe" if rctx.attr.platform.startswith("win") else ":bin/protoc",
+    )
 
-# TODO: add proto_library for each .proto file
-# and add deps[] in cases where they dep on each other
+    for src, deps in GOOGLE_PROTOBUF_DEP_EDGES.items():
+        build_content += """\
 proto_library(
-    name = "any_proto",
-    srcs = ["include/google/protobuf/any.proto"],
+    name = "{0}_proto",
+    srcs = ["include/google/protobuf/{0}.proto"],
+    deps = [":%s_proto" % dep for dep in {1}],
     strip_import_prefix = "include",
 )
-""".format(
-        protoc_label = ":bin/protoc.exe" if rctx.attr.platform.startswith("win") else ":bin/protoc",
-    ))
+""".format(src, deps)
+    rctx.file("BUILD.bazel", build_content)
 
 prebuilt_protoc_repo = repository_rule(
     doc = "Download a pre-built protoc and create a concrete toolchains for it",