[build] MVP for building with bazel (#6994)

shared/bazel/rules/gen/BUILD.bazel

@@ -0,0 +1,8 @@
+load("@rules_python//python:defs.bzl", "py_binary")
+
+py_binary(
+    name = "gen_resources",
+    srcs = ["gen_resources.py"],
+    tags = ["manual"],
+    visibility = ["//visibility:public"],
+)

shared/bazel/rules/gen/gen-resources.bzl

@@ -0,0 +1,10 @@
+def generate_resources(name, resource_files, prefix, namespace, visibility = None):
+    cmd = "$(locations //shared/bazel/rules/gen:gen_resources) --prefix={} --namespace={} --resources $(SRCS) --output_files $(OUTS)".format(prefix, namespace, resource_files)
+    native.genrule(
+        name = name,
+        srcs = resource_files,
+        outs = ["{}.cpp".format(input_file) for input_file in resource_files],
+        cmd = cmd,
+        tools = ["//shared/bazel/rules/gen:gen_resources"],
+        visibility = visibility,
+    )

shared/bazel/rules/gen/gen-version-file.bzl

@@ -0,0 +1,19 @@
+def _generate_version_file_impl(ctx):
+    out = ctx.actions.declare_file(ctx.attr.output_file)
+    ctx.actions.expand_template(
+        output = out,
+        template = ctx.file.template,
+        substitutions = {"${wpilib_version}": "TODO - Built with bazel"},
+    )
+    return [DefaultInfo(files = depset([out]))]
+
+generate_version_file = rule(
+    implementation = _generate_version_file_impl,
+    attrs = {
+        "output_file": attr.string(mandatory = True),
+        "template": attr.label(
+            allow_single_file = True,
+            mandatory = True,
+        ),
+    },
+)

shared/bazel/rules/gen/gen_resources.py

@@ -0,0 +1,58 @@
+import os
+import argparse
+import binascii
+
+
+def generate_file(resource_file, output_file, prefix, namespace):
+    func_name = "GetResource_" + os.path.basename(resource_file).replace(
+        "-", "_"
+    ).replace(".", "_")
+
+    with open(resource_file, "rb") as f:
+        raw_data = f.read()
+        hex = str(binascii.hexlify(raw_data), "ascii")
+        data = ", ".join("0x" + hex[i : i + 2] for i in range(0, len(hex), 2))
+        data_size = len(raw_data)
+
+    output = """#include <stddef.h>
+#include <string_view>
+extern "C" {{
+static const unsigned char contents[] = {{ {data} }};
+const unsigned char* {prefix}_{func_name}(size_t* len) {{
+  *len = {data_size};
+  return contents;
+}}
+}}
+namespace {namespace} {{
+std::string_view {func_name}() {{
+  return std::string_view(reinterpret_cast<const char*>(contents), {data_size});
+}}
+}}
+""".format(
+        func_name=func_name,
+        data_size=data_size,
+        prefix=prefix,
+        data=data,
+        namespace=namespace,
+    )
+
+    with open(output_file, "w") as f:
+        f.write(output)
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--namespace")
+    parser.add_argument("--prefix")
+    parser.add_argument("--resources", nargs="+")
+    parser.add_argument("--output_files", nargs="+")
+
+    args = parser.parse_args()
+    assert len(args.resources) == len(args.output_files)
+
+    for i, resource in enumerate(args.resources):
+        generate_file(resource, args.output_files[i], args.prefix, args.namespace)
+
+
+if __name__ == "__main__":
+    main()